Note: Descriptions are shown in the official language in which they were submitted.
..z .1~,-ii,-a~ ~_ '~'o_t~ _: i'lLi ~'..'.;3 147t;-.r +49 89 2:3994465:#/ 4.
VV111. V~. L1'1~I VI ~1~lYVLaa'a~ aLl I V/ V-/ I V.Tf-, ~17L/CA jtT1 f ~I
V11~,V TI IT
f CA 02314243 2000-06-13
.
43397
HYDR4XY-FUNCTtQNAt- P~l_YETHER t_AMiNATES
This invention relates to metal-polymer laminates useful for fabricating
articles, such as beverage containers and aerosol containers.
Metal-p~alymer laminates are known and ate described, for example, in
U.S. Patents 4.62&,157; 4,423;823; 4,034,132; 4,686,952; 4,734,303 and
4,361,020. The
polymers employed in preparing the laminates include polyesters,
polypropylene,
polyethylene, poiycarbonate, polyimide and blends thereof. Films prepared from
these
polymers suffer from their inadequate adhesion to the metal, their inability
to elongate
during metal forming due to the highly oriented nature of the polymer film,
and their
n0 tendency to delaminate during forming andlor end-use application. Thin
palyolefin-based
films with polar comonomer adhesive layers, while offering good adhesion
characteristics
to metal, and good elongation during metal laminate forming, can suffer from
inadequate
IaminGte cuttabitity (resulting in coating "stringing"), and inadequate
scratch resistance and
end-use toughness.
It would be desirable to provide polymer films with such characteristics
as adequate toughness, abrasion resistance, thermal stability, ductility,
formability, good
barrier properties and chemical resistance to many chemicals.
In a first aspect, the present invention is a laminate structure comprising
one or more layers of a metal and one or more layers of a hydroxy-functional
polyether
.?0 and, optionally, one or more layers of an organic polymer which is not
hydroxy-functional
polyether.
In a second aspect, the present invention is a container comprising a
laminate structure having one or more layers of a metal and one or more layers
of a
hydroxy-functional pol;rather and, optionally, one or more layers of an
organic polymer
:25 which is net hydroxy-functional polyether.
Preferably, the hydroxy-functional polyetherhydroxy-functional polyethers
employed in the practice of the present invention for preparing the polymer
iayer(s) are:
(1 ) hydroxy-functional polyethers having'repeating units represented by the
formula:
OH
OCH2CCHzDA~ z
R
n
~I~~li~lED SHEET
CA 02314243 2000-06-13
WO 99/32281 PCT/US98/12430
(2) amide- and hydroxymethyl-functional polyethers having repeating units
represented by
the formula:
OH OH
OCH2CCHZOArI OCHzCCH20Ar2 II
I R x ~ R
1-x
n
(3) hydroxy-functional poiy(ether sulfonamides) having repeating units
represented by the
formula:
OH R2 O O R2 OH
OCHZCCHZN-IS-R~ SI-NCH2CCH20Ar IIIa
I
R O O R
n
or
OH
OCHzCCH2-N-CH2 i CH20Ar I IIb
O-SAO R
a n
(4) poly(hydroxy amide ethers) having repeating units represented
independently by any one
of the following formulas:
OH O O
OCH2CCH20Ar-NHC-R1 CINHAr IVa
I
R
n
OH 0 O
OCH2CCH20Ar-CNH-R1 NHCAr I~
I
R
n
or
-2-
CA 02314243 2000-06-13
WO 99/32281 PCT/US98/22430
OH O
OCH2CCH20ArCNHAr IVc
I
R
n
(5) poly(hydroxy ester ethers) having repeating units represented by the
formula:
O OH O O CHZOH
Rl-C~O CHzCCH20R1 OCI-Rl-CIOC-CH
R R
~l-(x+y) y x
(6) poly(hydroxy amide ethers) having repeating units represented by any one
of the
following formulas:
off o 0 off
OCH2CCH20Ar-NHC-R1 CNH-Ar-OCH2~CH20Ar2 VIa
R R
n
OH O O OH
OCH2CCHZOAr-CNH-R1 NHC-Ar-OCH2~CH20Ar2 VIb
R R
n
or
OH 0 OH
OCH2CCH20Ar-CNH-Ar--OCH2~CH20Ar2 VIc
R R
n
(7) poly(hydroxyamino ethers) having repeating units represented by the
formula:
OH OH
OCH2 i CH2-A-CH2 i CH20Ar VI I
R R
n
-3-
CA 02314243 2000-06-13
WO 99/32281 PCT/US98/Z2430
and
(8) hydroxy-functional polyethers having repeating units represented by the
formula:
OH OH
OCH2CCHz-X-CH2CCH20-Ar3 VIII
I
R R
n
wherein each Ar individually represents a divalent aromatic moiety,
substituted divalent
aromatic moiety or heteroaromatic moiety, or a combination of different
divalent aromatic
moieties, substituted aromatic moieties or heteroaromatic moieties; R is
individually
hydrogen or a monovalent hydrocarbyl moiety; each Ar' is a divalent aromatic
moiety or
combination of divalent aromatic moieties bearing amide or hydroxymethyl
groups; each Arz
is the same or different than Ar and is individually a divalent aromatic
moiety, substituted
aromatic moiety or heteroaromatic moiety or a combination of different
divalent aromatic
moieties, substituted aromatic moieties or heteroaromatic moieties; R' is
individually a
predominantly hydrocarbylene moiety, such as a divalent aromatic moiety,
substituted
divalent aromatic moiety, divalent heteroaromatic moiety, divalent alkylene
moiety, divalent
substituted alkylene moiety or divalent heteroalkylene moiety or a combination
of such
moieties; R2 is individually a monovalent hydrocarbyl moiety; A is an amine
moiety or a
combination of different amine moieties; X is an amine, an arylenedioxy, an
arylenedisulfonamido or an arylenedicarboxy moiety or combination of such
moieties; and
Are is a "cardo" moiety represented by any one of the following formulas:
R2 v ~ R1
-4-
R2 R2
CA 02314243 2000-06-13
WO 99/32281 PCTNS98/22430
R2
or
R2 ~ ~~Rz
wherein Y is nil, a covalent bond, or a linking group, wherein suitable
linking groups include,
for example, an oxygen atom, a sulfur atom, a carbonyl atom, a sulfonyl group,
or a
methylene group or similar linkage; n is an integer from 10 to 1000; x is 0.01
to 1.0; and y is
0 to 0.5.
The term "predominantly hydrocarbylene" means a divalent radical that is
predominantly hydrocarbon, but which optionally contains a minor amount of
heteroatomic
moiety such as oxygen, sulfur, imino, sulfonyl, or sulfoxyl.
The hydroxy-functional polyethers represented by Formula I can be prepared,
for example, by allowing a diglycidyl ether or combination of diglycidyl
ethers to react with a
dihydric phenol or a combination of dihydric phenols using the process
described in
U.S. Patent 5,164,472. Alternatively, the hydroxy-functional polyethers are
obtained by
allowing a dihydric phenol or combination of dihydric phenols to react with an
epihalohydrin
by the process described by Reinking, Barnabeo and Hale in the Journal of
Applied Polymer
Science, Volume 7, page 2135 (1963).
The amide- and hydroxymethyl-functional polyethers represented by Formula
II can be prepared, for example, by reacting the diglycidyl ethers, such as
the diglycidyl ether
of bisphenol A, with a dihydric phenol having pendant amido, N-substituted
amido and/or
hydroxyalkyi moieties, such as 2,2-bis(4-hydroxyphenyl)acetamide and
-5-
R2 R2
R2 R2
CA 02314243 2000-06-13
WO 99/32281 PCT/US98/22430
3,5-dihydroxybenzamide. These polyethers and their preparation are described
in
U.S. Patents 5,115,075 and 5,218,075.
The hydroxy-functional poly(ether sulfonamides) represented by Formula III
are prepared, for example, by polymerizing an N,N'-diaikyl or N,N'-
diaryldisulfonamide with a
diglycidyl ether as described in U.S. Patent 5,149,768.
The poly(hydroxy amide ethers) represented by Formula IV are prepared by
contacting a bis(hydroxyphenylamido)alkane or arena, or a combination of 2 or
more of
these compounds, such as N,N'-bis(3-hydroxyphenyl) adipamide or
N,N'-bis(3-hydroxyphenyl)glutaramide, with an epihalohydrin as described in
U.S. Patent 5,134,218.
The poly(hydroxy ester ethers) represented by Formula V are prepared by
reacting diglycidyl ethers of aliphatic or aromatic diacids, such as
diglycidyl terephthalate, or
diglycidyl ethers of dihydric phenols with, aliphatic or aromatic diacids such
as adipic acid or
isophthalic acid. These polyesters are described in U.S. Patent 5,171,820.
The poly(hydroxy amide ethers) represented by Formula VI are preferably
prepared by contacting an N,N'-bis(hydroxyphenylamido)alkane or arena with a
diglycidyl
ether as described in U.S. Patents 5,089,588 and 5,143,998.
The polyetheramines represented by Formula VII are prepared by contacting
one or more of the diglycidyl ethers of a dihydric phenol with an amine having
two amine
hydrogens under conditions sufficient to cause the amine moieties to react
with epoxy
moieties to form a polymer backbone having amine linkages, ether linkages and
pendant
hydroxyl moieties. These polyetheramines are described in U.S.
Patent5,275,853.
The hydroxy-functional polyethers represented by Formula VIII are prepared,
for example, by contacting at least one dinucleophilic monomer with at least
one diglycidyl
ether of a cardo bisphenol, such as 9,9-bis(4-hydroxyphenyl)fluorene,
phenolphthalein, or
phenolphthalimidine or a substituted cardo bisphenol, such as a substituted
bis(hydroxyphenyl)fluorene, a substituted phenolphthalein or a substituted
phenolphthalimidine under conditions sufficient to cause the nucleophilic
moieties of the
dinucleophilic monomer to react with epoxy moieties to farm a polymer backbone
containing
pendant hydroxy moieties and ether, imino, amino, sulfonamido or ester
linkages. These
hydroxy-functional polyethers are described in U.S. Application Serial No.
131,110, filed
October 1, 1993.
-6-
CA 02314243 2000-06-13
WO 99/32281 PCT/US98/22430
The hydroxy-functional polyethers commercially available from
Phenoxy Associates, Inc. are suitable for use in the present invention. These
hydroxy-
functional polyethers are the condensation reaction products of a dihydric
polynuclear
phenol, such as bisphenol A, and an epihalohydrin and have the repeating units
represented
by Formula I wherein Ar is an isopropylidene diphenylene moiety. The process
for preparing
them are described in U.S. Patent 3,305,528.
Most preferably, the hydroxy-functional polyethers employed in the practice of
the present invention are the polyetheramines represented by Formula VII.
Preferably, the hydroxy-functional polyethers exhibit a molecular weight of at
least 20,000 but less than 100,000, and preferably at least 30,000 and less
than 80,000.
Hydroxy-functional polyethers having low molecular weight or exceedingly high
molecular
weight are difficult to process and exhibit insufficient physical properties
to form into flexible
films or adequately wet-out and adhere to a metal substrate.
To improve the chemical resistance, hardness, thermal resistance or other
performance characteristics of the hydroxy-functional polyethers, the
polyethers can be
modified by known copolymerization or graft copolymerization techniques or by
cross-linking
with ethylenically unsaturated dicarboxylic acid anhydride or anhydride
precursor such as
succinic or malefic anhydride; diisocyanates, or formaldehydes, such as phenol-
, urea- or
melamine formaldehyde. Such reactions (copolymerization, cross-linking) can be
performed
by a reactive extrusion process wherein the reactants are fed into and reacted
in an extruder
using the conditions described in
U.S. Patent 4,612,156. Such reactions can also take place after the films or
laminates are
formed by thermal, moisture or UV-induced reactions.
Monolayer and multilayer films can be prepared from the hydroxy-functional
poiyethers by using conventional extrusion techniques such as feedblock
extrusion,
multimanifold or die coextrusion or combinations of the two, or by slot-die
casting or annular
blown film extrusion; extrusion coating onto another substrate layer; or by
solvent spraying
or solution casting. Solution casting is a well known process and is
described, for example,
in the Plastics Engineering Handbook of the Society of the Plastics Industry,
Inc, 4th Edition,
page 448. Additionally, multiple plies of hydroxy-functional polyethers and/or
other organic
polymers can be adhered together via a conventional process such as hot-roll
thermal
lamination in order to produce a multi-ply structure. This lamination of
multiple separate
layers or plies is especially beneficial when significant melt viscosity
differences between the
_7_
. i v- is-~~ ._ -ys : ;s r : / 13 '?:z3 1476- +49 89 223994465 : # 5
,..~. ;.~: .....~ ~,'; y;;.:""~,~ CA p2314243~ 2000-06-13'~~ ~,.".~ .~.t~~
~~~..., "~.. ~. u~., ,., ...
4335?
various layers prevent uniform coextrusion of the layers. The films can
be subsequently oriented monoaxially, in the machine or transverse direction,
or biaxially,
in both machine and transverse directions, to further improve their physical
properties,
such as increased tensile strength and secant modulus and reduced elongation.
These
fi property changes can be beneficial when stamping or cutting a polymer-metal
laminate. In
general, multilayer films can be formed from the hydroxy-functional polyethers
of the
present invention by coe:xtruding one or more layers of the hydroxy-functional
pofyethers
and one or more layers .of an organic polymer which is not a hydroxy-
functional polyether.
Such multilayered structures, whether formed via coextrusidn, extncsion
coating, liquid
1 (i coating or multl-ply lamination, can be beneficially used to achieve
composite properties
not attainable by monolayer film or multicomponent blends. One such example
involves
the use of coextrusion to add an organic adhesive layer to an otherwise poorly
adhering
hydroxy-functional polyether to bond the phenoxyether polymer to a metal
substrate. In
preparing the monolayer and multllayer films, thermoplastic poiyurethanes
(TPU),
1 °i thermoplastic elastomer {TPE), polyester (PET), glyol-modified
copolyester {PETG),
polyolefins or other therrnoplastic resins can be blended with the hydroxy-
functional
polyether at levels of less than 50 weight percent end, preferably less than
30 weight
percent, based on the weight of the hydroxy-functional polyether layer. These
other
polymers can be bJendes~ into the hydroxy-functional palyether in order to
reduce
2C~ composition cast, to modify physical properties, barrier or permeability
properties, or
adhesion characteristics.
additives such as fillers, pigments, stabilizers, impact modifiers,
plasticizers, carbon black, conductive metal particles, abrasives and
lubricating polymers
may be incorporated into the hydroxy-functional poiyether films. The method of
25 incorporating the additives is not critical. The additives can conveniently
be added to the
hydroxy-functional polyether prior to preparing the films. if the polymer is
prepared in solid
form, the additives can be added to th~ melt prior to preparing the films.
Preferably, the hydroxy-functional polyether films exhibit an ultimate
tensile strength of at least 48.3 M Nlm~ (7,000 psi), a yield elongation of 4
to 1Q percent, an
34 ultimate elongation of SO to 400 percent arid a 2 percent secant modulus of
at least 137x.0
M nilmZ (200,000 psi.) The relatively high tensile strength, high rnodulus and
low
elongation of the film allows the film laminate to be cut and stamped in a
high speed die
cutting operation without undesirable f:lm elongation and stringing over t#ie
edge of the cut
mete; laminate in an open-anon used to produce aerosol valve mounting cups. As
used
35 herein, the term "stringing" refers to a partially attached polymeric
coating fiber or "hair"
caused by the incomplete cutting of the metal
_g_
~;f~EC~L~~~ Se-~~ T
CA 02314243 2000-06-13
WO 99/32281 PCTNS98/22430
laminate coating. The tough, elongatable polymeric coating is stretched over
the cut edge of
the metal where it is partially cut off; leaving either a ragged edge of
polymer or a thin
partially detached polymer strip, hair, string or fiber. It is also desirable
that the hydroxy-
functional polyether film exhibits a minimum of 2.0 Ib/inch adhesion to a
metal substrate,
preferably a minimum of at least 3.0 Ib/inch.
The monolayer film comprises the hydroxy-functional polyether.
Organic polymers which are not hydroxy-functional polyethers can be
adhered to one or both sides of the hydroxy-functional polyether film layer to
produce a
multilayer film. Thus, the multilayer film can be in the form of the following
structures:
(1 ) a two-layer film comprising a first layer of the hydroxy-functional
polyether
and a second layer comprising an organic polymer which is not a hydroxy-
functional
polyether.
(2) a three-layer film comprising a first outer layer of an organic polymer, a
core layer of the hydroxy-functional polyether and a second outer layer of an
organic
polymer which is the same as or different from the organic polymer of the
first outer layer;
(3) a three-layer film comprising a first outer layer of the hydroxy-
functional
polyether, a core layer of an organic polymer which is not a hydroxy-
functional polyether and
a second outer layer of an arganic polymer which is the same as or different
from the
organic polymer of the core layer; or
(4) a three-layer film comprising a first outer layer of the hydroxy-
functional
polyether, a core layer of an organic polymer which is not a hydroxy-
functional polyether and
a second outer layer of a hydroxy-functional polyether which is the same as or
different from
the hydroxy-functional polyether of the first outer layer.
Organic polymers which are not hydroxy-functional polyethers which can be
employed in the practice of the present invention for preparing the multilayer
film include
crystalline thermoplastic polyesters, such as polyethylene terephthalate
(PET), amorphous
thermoplastic polyesters such as glycol modified polyester (PETG); polyamides,
polyolefins,
and [polyolefins] styrenics based on monovinyl aromatic monomers; carboxylic
acid modified
olefin copolymers, such as ethylene-acrylic acid and ethylene-methacrylic acid
copolymers,
and anhydride-modffied polymers, such as polyethylene grafted with malefic
anhydride,
ethylene-vinyl acetate-graffed with malefic anhydride and ethylene-
butylacrylate-malefic
anhydride terpolymer.
_g_
. _ _., ..~- .. s..., - au ~ lad :GG:3 14 !b--~ t~~ ~5 23994'465 : ~f E
VV111. Yr. LI711 VI 1 iVL.'_.. Vf 1~u LLV! 111'J, lit 1V/J.I .V.1V~ Js a.oa
A~TII,I 411~.V Vf .t
CA 02314243 2000-06-13
433E37
Polyssters and methods for their preparation are well known in the ark
and referencr~ is made thereto for the purposes of this invention. For
purposes of
illustration and not limitation, reference is particularly made to pages 1-B2
of Volume 12 of
the EncyGopedia of Polymer Science and Engineering, 1988 revision, Jahn Wiley
8~ Sons.
Polyamides which can be employed in the practice of the present
invention include the various grades of nylon, such as nylon 6, nylon 6& and
nylon 12.
Also included era lower rnQlecular weight and lower viscosity polyantide
copolymers which
are used as hot-melt adhesives and which are well known in the art and are
commercially
available from numerous suppliers.
Polyolefins which can ba employed in the practice of the present
invention for preparing the multilayer laminate structure include
polypropylene,
polyethylene, anti oapolymers and blends thereof, as well as ethylene-
propylenediene
terpolymer$. Preferred poiyolefiins are polypropylene, linear high density
polyethylene
(Hf3PE), heterogeneously branched linear low density polyethylene (LLDPE) such
as
DOWLF~CzM polyethylene resin (a Trademark of The Dow Chemical Company)
heterogeneously-branched ultra low linear density polyethylene (ULDPE) such as
ATTANE'"' ULDPE (a xradsmark of The Dow Chemical Company); homogeneously-
branched, linear ethylersela-olefin copolymers such as TAFMERTM (a trademark
of Mitsui
Petrochemicals Company Limited) and EXACTT"' (a trademark of Exxon Chemical
Company); hornogenecrusly-branched, substantially linear ethylenela-olefin
polymers such
as AFFlNIT'YT'" (a Trademark of The Dow Chemical Company} and ENGAGE'" (a
Trad6mark of du Pont Dow Elastomers l..L.G.) polyoletin elastomers, which can
be
prepared as disclosed in U.S. Patents 5,272,236 and 6,278,272; and high
pressure, free
radical polymerized ethylene polymers and copolymers such as low density
polyethylene
(LDPE), ethylene-acrylic acid (EAA) copolymers such as PRiMAGdRT"" (Trademark
of The
Dow Chemical Company), and ethylene-vinyl acetate (EVA) copolymers such as
ESCORENET'" polymers (a Trademark of F~ocon Chemical Company}, and ELVAX'~" (a
Trademark of E.I. du Pont de Nemours & Co.). The mare preferred pofyolefins
are the
homogeneously-branched linear and substantially linear ethylene copolymers
with a
density (measured in alccordance with ASTM D-792) of 0.85 to O.JtiS glcc, a
weight
average molecular weight to number average molecular weight ratio (M~JM~) from
1.5 to
3.0, a measured melt index (measured in acGOrdance with ASTM D-1239
(19012.1fi)) of
0.01 to 100 g11~ min, and alt I,~llz of 6 to 20 (measured in accordance with
ASTM D-1238
( 190/10)).
-10-
i~' = ..
_ _ .LT f v--~ ~~t:J 0.7 ~c7.7aJ'YtOL7 ~ 3f l
v '. t l v V ~ ~ L P1 ~ 1 V I I 1 V V ~ I V L L V 1 1 1 V ~ ~ IyL. l I V I V J
I V . T V , l C L t l~ T/ T l f ~ l V y lr 1 1 I t
CA 02314243 2000-06-13
43357
In general, high density polyethylene (HDPE) has a density of at least
about 0.94 grams per cubic centimetar (glcc) (ASTM Test Method p-1505). HD PE
is
commonly
-t 014-
AMEfdDtD S~~'
. . o ._t.s 1't IU-~ t&'J~ Li:l :f:~:1~J44s5: ~ a
VV111. Vr. VflY1 V11 iVL _-~ -- V'~ ' LLV ~J~.Vn .L/ IV/VV IV.TT, JCLffA
j,Tlf,1 Vl~.r Vl .1
. CA 02314243 2000-06-13
i . 4:~3t~7
produced using techniques similar to the preparation of linear low density
polyethylenes. Such techniques are described in U.S. Patents 2,825,721;
2,993,876; 3.250,825
and 4.204,050. The preferred HDP~ employed in the practice of the present
invention has a
density of from 0.94 to 0.99 glcc and a mail index of from 0.01 io 35 grams
per 10 minutes as
determined by ASTM Test Method D-1238.
Styrenics based on monovinyl aromatic monomers which can be employed in
the practice of the present invention include polystyrene, poiymethylstyrene,
styrene-acrylonitrile,
styrene-malefic anhydride copolymers, styrenelmethyistyrene or
styrene/chlorostyrene copoly-
mars.
Other organic polymErs which can be employed in the practice of the present
invention for preparing the multilayer film inGude polyhexamethylene
adipamide,
polycaprolactone, polyhexamethylene sebacamide, polyethylene 2,fi-naphthalate
and
polyethylene 1,5-naphthalate, poiytetramethylene 9 ,2-dioxybEnzoate and
copolymers of ethylene
terephthalate and ethylene isophthalate.
The thicknes$ of the monolayer or multilayer fllm is dependent on a number of
factors, including the intended use, materials stared in the container, the
length of storage prior to
use and the specific composition employed in each layer of the laminate
structure.
In general, the monoiayer film will have a thickness of from 2.5 to 250 Nm
(0.1 to
10.0 mils), preferably from 5.08 to 121 Nm (0.2 to 5.0 mils) and most
preferably. 10.2 to 25.1 Nm
(0.4 to 1.0 mils). The muitifayer ~Im will have a total thickness of from 2.5
to 260 Nm (0.1 to
10.0 mils), preferably from 5.08 to 127 pm (0.2 to 5.0 mils); with the
thickness of the hydroxy-
functional polyether iayer~;s) aeing from 10 percent to 90 percent, and
preferably 20 percent to 80
percent of the total film thickness.
The metals which can be employed in the practice of the present invention for
preparing the polymer-metal or polymer-metal-polymer laminate include tin
plate steel (TPS), tin-
free steel (TFS), electrochrame-coated steel (~CruS), galvanised steel, high
strength low alloy
steel, stainless steel, copper-plated steel, copper and alurninurri. The
preferred metals are tin
plate steal and tin-free steel. Preferably, the metal is in the form of a flat
sheet having two major
surfaces.
3~J Far most metal packaging appiicatlans, the metal typically ranges from
76.2 to
508 um (3 to 20 mils) in thickness, although the hydroxy-functional polyether
film can be adhered
to any gauge metal. it is within the scope of this present invention to
laminate the hydroxy-
functional polyether film to thin metal foil such as 5.08 to 50.8 Nm (0.2 to 2
mil) aluminum foil
used in flexible packaging.
-11-
A~~Ef~~E~ SI'~~~'~
CA 02314243 2000-06-13
WO 99/32281 PCT/US98/22430
The polymer-metal or polymer-metal-polymer laminates of the present
invention can be prepared by conventional lamination techniques. As is known
in the art,
specific laminating techniques include thermal lamination, that is, whereby an
inherently melt
activated adhesive film is heated and melt-bonded to a metal substrate by
means of heat
and pressure; or liquid coating and laminating, that is, whereby a separate
adhesive such as
a solvent-borne or aqueous-based adhesive is applied to the polymeric film or
metal
substrate at a desired thickness, the liquid driven off by a drying oven, and
combining the
film and the metal with heat and pressure to bond the two layers together. In
a similar
fashion to liquid coating, a hot-melt adhesive can be melted and applied by
means of slot die
coating or roll coating onto either the film or the metal and joining the hero
plies of film and
metal together with pressure using the molten hot-melt adhesive to intimately
bond the
structure together, followed by cooling.
In general, a two-ply laminate comprising a polymer film layer and a metal
layer can be prepared in accordance with the present invention by contacting
one of the
major surfaces of the metal layer with the polymer film at an elevated
temperature with
concurrent application of pressure. Similarly, a three-ply laminate comprising
a polymer film
layer, a metal layer and a palymer film layer is formed by applying to the
remaining major
surface of the metal layer another polymer film layer which is the same as or
different from
the other polymer film layer,.
The polymer-metal or polymer-metal-polymer laminates can have any one of
the following structures:
(a) a two-ply laminate comprising a first layer of a hydroxy-functional
polyether (hydroxy-functional polyether) and a second layer of a metal;
(b) a three-ply laminate comprising a first outer layer of an organic polymer
which is not hydroxy-functianal polyether, a core layer of HPEE and a second
outer layer of
a metal;
(c) a three-ply laminate comprising a first outer layer of hydroxy-functional
polyether, a core layer of an organic polymer which is not hydroxy-functional
polyether and a
second outer layer of a metal;
-12-
CA 02314243 2000-06-13
WO 99/32281 PCT/US98/22430
(d) a three-ply laminate comprising a first outer layer of a hydroxy-
functional
polyether, a core layer of a metal and a second outer layer of an organic
polymer which is
not a hydroxy-functional polyether; and
(e) a three-ply laminate comprising a first outer layer of a co-extruded
hydroxy-functional polyether/PETG film, a core layer of a metal and a second
outer layer of
an organic polymer which is not a hydroxy-functional polyether.
Preferably, the organic polymer which is not a hydroxy-functional polyether is
polypropylene.
In the above structures, the organic polymer which is not a hydroxy-functional
polyether (hydroxy-functional polyether) can be a blend of two or more
different organic
polymers.
The polymer-metal or polymer-metal-polymer laminates of the present
invention are suitable for use in the manufacture of three-dimensional metal
structures, such
as, for example, aerosol containers and its various parts, where pressure
sealing is obtained
by forming a crimped edge with the polymeric layer tightly engaged between two
layers of a
steel sheet. Typically, an aerosol container comprises a can body or wall,
which may be
formed in one piece, or which may comprise a can body cylinder closed at its
bottom end by
an end member and at its top end by a domed cover member. The one-piece
aerosol can
body, or the domed cover member, has a mouth which is itself closed by a valve
cup,
carrying the aerosol dispensing valve. The valve cup is usually swaged or1 to
the body. The
polymer-metal or polymer-metal-polymer laminates of the present invention are
particularly
suitable for use in the manufacture of aerosol valve mounting cups, aerosol
can domes and
bottoms and can wall or body assembly.
In addition, the polymer-metal or polymer-metal-polymer laminates of the
present invention may be employed in the preparation of other containers where
a chemical,
corrosion and pressure resistant seal is desired. Furthermore, in the
manufacture of metal
paint cans, the bottom of such cans may be stamped and formed from metal-
polymer
laminates and joined to the cylindrical sides of the can by formation of a
crimped seal. The
resulting seam is impervious to solvents and other chemicals shipped in the
container and
maintains a teak-proof seal. Formation of such metal cans using the components
formed
from the present metal-polymer laminate eliminates the need for separate
application of a
gasketing material such as an isoprene rubber around the perimeter of a
circular-shaped
blank and the curing thereof with its concomitant solvent emissions. Utilizing
coated metals
-13-
.. .. . ~ >.~_,- i.:.-as . ca ~ a~ : /~/~ ! 1:.3 a!'.r3 1476-. +49 89 ?3994465
: øt 9
yVIpL Vr. LI~.t VI~1 1~VL' I CA 02314243 2000-VV- L/ 1 V/ J.J 1 V.TT, ~LLtCI.
71'Tt ( ~p yyV J/ IT
433!7
according to the present invention strsamllnes the metal paint can
manufacturing process" resulting in improved efficiency.
The polymer-metal laminates of the present invention can be desp-
drawn into formed containers such as beverage containers or food packaging
container; or
metal bulk packaging containers. The thermoplastic nature of the hydroxy-
functional
polyethsr film allows the polymeric coating to sufficiently elongate and draw
as the can
structure is mechanically formed. Conventional thermoset coatings such as
cured epoxy
coatings are fairly brittle and will fracture upon significant elongation of
the metal substrate,
such as occurs during deep drawing of 1-piece can bodies.
Additionally, large metal structures such as domestic appliance shells
can be fabricated from the polymer-metal laminates of the present invention.
Domestic
appliances, which include refrigerator, washing maci~ine, clothes dryer, and
dishwasher,
require exterior and interior surface finishes that are adherable tn metal,
and are forrnable,
durable, scratch and abrasion resistant, solvent resistant, and aesthetically
pleasing. A
18 hydroxy-functional poiyather (hydroxy-functional polyethar) film laminate
can replace the
cured solvent-based primer andlor paint finish typically used with preformed
postpainted
appliance shells. The ductility and formability of pigmented hydroxy-
functional poiyether
film-metal laminate permits the precoated coiled steel to be formed into the
appliance shell
without needing to be painted after forming."
The following Examples are for illustrative purposes only and are not
intended to limit the scope of this invention. Unless otherwise indicated, all
parts and
percentages are by weight.
Exam~~te 1
A monolayer 0.8 mil (20 micron) hydroxy-phenoxyether (phenoxy~ film
2~ was producEd via conventional cast film extrusion using a phenoxy resin
having a Tg of
100°C and a molecular weight of 50,000, available from Phenoxy
Associates as Pa Phen
PKFE. The film was extruded at a melt temperature of 228°C, quenched on
a chill roll at
E5°C, further cooled to 30°C, and wound into a film soil. The 20
micron film was then
separately thermally larninated onto pre-heated 2fi7 micron (90.5 mil) tin
plate steel at a
3~3 temperature of 204°C using a continuous cola metal lamination
process and then quenched
to room temperature using forced air cooling, followed by water-cooled chill
rolls. The
phenoxy film exhibits excellent adhesion to the metal and could not be
delaminated from
the m$tal without cohesive failure (tearing of the film at peel levels greater
than 5.25 Nlcm
(3.0 Ibllnch).
-14'
~tE~d~~D ~~~~~
w.ii~ uy. ,.n.. v. ~ yvi=-.. __ ..... ice. .r ~ .:y.uu . W~ ,'-
~'v~.r.i~~Vu.T.r~ i+4J 89 2399~4~5~#10
CAV02314243 2.000-06-13
43.397
a le
A two-layer coextrudad 15 micron (0.6 mil) film was produced from a
glycol-modified copolyester (PETG), available from Eastman Chemical Company as
PETG
fi783 resin and a phenoxy resin (PaPhen PKFE). A conventional multifayered
cast film line
was used. the PETG resin was extruded at a melt temperature of 225°C in
one layer,
while the phenoxy resin was extruded at 225°C In a second adjacent
layer. The 15 miaon
f~Jm comprises a fi0 percent PETG layer and 40 percent phenoxy layer, based on
the film
thickness. The coextruded iwo-layer frlrn was quenched on a chill roll at
85°C, further
cooled to 30°G, and wound into a film roll. The 15 rrticron was then
Thermally laminated
onto pre-heated 267 micron (10.5 mil) tin plate steel at a temperature of
204°C (400°F)
f with the phenoxy layer bonded to the metal and then quenched to room
temperature using
forced-air cooling followed by water-cooled shill rolls. The phenoxyIPETG film
could not be
delaminated from the metal without destructive tearing of the fclm.
t5 Physical Properties of Films of Example 1 8 2:
Film MDUW ~Ui6
niate MD% TD MD
lo lo Ultimate
Tensile Tensile Yield Yi6ld Elongation
(%)
M t~;mZ M Wma ElongationElor~on(~)
%
Ex. 69.0 55.2 9 fi 1 TO
1
10000 SOOD
si si
Ex. S0, 0 37.2 $ _ ~ 170
2
8700 si 5400
si
?.0 Physical Properties of Films of Example 1 & 2 (continued):
f
Film Tt?/ UIGrnateMD 2~ TD 2J MD Elm. TD Elm. Spencer
~Ongaton Secant Secant Tear Tear impact
(%)
ModuiusModules StrengthStrength (glNm)
M Nlmz M Nlm2 ( I m ! m
Ex 200 1909.9 18$,2.3 305 330 7't93
7
(ZT~r700p~i(273000 (12 9lmiJ)(13glmfl)(295
psi) g/mii
2A.0 1813.3 1703.6 1651 254 5$58
I
p~3oo0psi)(25~ooppsi)(65 Imil1d /rnil 270 mil
-t 5-
~~Ef~~lct~ S~c~'~
_ __ . sv~:~I _. f1J L.tJ 1'tWb-~ -r~~ ts~ :1:3J:j44fi5:~#~.1
V V . W V't . W ~1 V 1 1 i V L _~ ~ _ - a w 1... V V " V . L 1 1 V 1 J .J . V
. ~ J ~ ~tSL. tlr, ,j 1 1 f ~ 1 V 1j '- . I ! . t
CA~02314243~2000-06-13
43397
x r IP
The iwo-fayer phenoxyIPETG film of Example 2 was thermally laminated
to a 7E~ micron (10.5 milt' tin plate steel at a temperature of 204°C
(40Q°F) with the PETG
layer contacting the preheated metal. The film exhibited excellent adhesion to
the metal
.5 and could not be delaminated.
~, a
A monclayer film of a poly(hydroxy amino ether) (PNAE) resin was made
on a conventional cast ~1rn line. The PHAE resin was prxluced from the
reaction of the
diglycidyl ether of bisphenol A (DGEBA) and monoethanolamlne (MEA) following
the
i0 procedure described in U.S. Patent 5,275.853, and had a Tg of 70°C
and a molecular
weight of 60,000. The 12.7 micron (0.5 mil) film was ea~truded at a melt
temperature of
210°C and quenched t~.n a cooled casting roll at 85°C, prior to
being further quenched to
30°C and wound into a roll. The film was thermally laminated to a 2C7
micron (10.5 mil) tin
plate steel, a s mil alurrdnum and a 6 mil ECCS at a temperature of
204°C. In ail three
15 cases, the PHAE film exhibits excellent adhesion to metal and could not be
peeled from
the metal.
xa a 5
d~tv~~o-layer coextrudad film of PHAE and ethylene-acrylic acid (9 percent
AA) was made via conventional cast film coextrusian. Both resins were extruded
at 21D°C
20 and quenches at 65°C prior to being further cooled to 30°C
and rolled into a film roll. The
25.4 micron (1.0 mil) film was produced with a layer ratio of 5t) percent of
PHAE and 50
percent of ethylene-acrylic gad (AAA). The rtlm was then thermally laminated
to a
preheatEd tin plate steel at a04°C, with the EAA layer of the
coextruded film contacting
and adhering to the steel. The film exhibited tn excess of 5.25 Nlcm (3.0
Iblinch) adhesion
25 io the metal and could not be~ peeled without destruction of the film.
~.xample 6 .
A 15 micron (0.6 mi!) biaxially oriented polyester (OPET) ftlm was coated
with a solvent-basal phenoxy solution (40 percent phenoxy solids in methyl-
ethyl ketone,
available from Phenoxy Associates as UCAR PKHS-a0). A conventional liquid
water was
30 used to apply the wet liquid ;gating tv one site of the aPET film. The wet-
coated film was
than transported through 2 multizone hot air impingement drying oven (zone
temperatures:
9a°i= to 150°F, 32°C to 55°C) to dry off the
solvent, leaving a 5.08 pm (0.2 mil) solid
phenoxy layer on the
-16-
~i:~t:ar7 ~t-t':.~ (
n av ~.-:~, 1~t tC~-~ t~J 23J :lii.~.y~~(jJ ~ # 1~
....., r ..~ . .~r~n u. . rv' . . _- _ _~ . v r.sy.... -iv . v, 1.1 . vI ....r
. v.-wr, lvm pm . ,. .r.'y.. W
CA 023142432000-06-13
43397
i
15 Nm (t3.6 mil) OPET film. The 20.3 Nm (0.8 mil) coated OPET film was
' then wound into a roll. The film was later thermally laminated onto pre-
heated fin plate
steel at 2p4°C using a coil metal lamination line, with the phenoxy
layer adhEred to the
metal surtace. The hot laminate was then quenched to room temperature using
forced-air
coolJng and water-cooled chill rolls.
xmle7
The metal laminates of Examples 1, 2, 3, 4, 5 and 6 were drawn and
formed into a 33 mm diameter by 12 mrn deep cup using a Tinius Olsen
Ductomatic BUP
200 metal forming press. Cups with the laminae thin film on the outside of the
cup and
with the laminate thin f.lm on the inside of the cup were produced. The thin
films
exhibitedexcellent adhesion to the formed metal with no film delamJnation
observed.
Example 8
Multilayered metal laminates using the same phenoxy-based films of
Examples 1,2,3 and 4 were produced with a eoextruded 183 Nm (7.2 mil)
polypropylene
(PP)-ultra linear low density polyethylene (ULLOPE) blend film simultaneously
laminated
onto the opposite side of the metal from the phenoxy-based film. The
polypropylene film
was a two-Layer coextrusion with a 50 percent PP and 54 percent ULLDPE main
layer
(85 percent of filrn gauge) and a malefic anhydride grafted polyethylene
adhesive layer
(15 percent of film gauge), which was made in accordance with the teachings of
2~~ U.S. Patent 5, 006,383. The 183Nm PP flm was laminated to the top side of
a preheated
267 pm (10.5 mil) tin plate steel and the respective Example 1, 2, 3 or 4
phenoxy-based
flrn of O.a to O.B mil gauge was laminated to the bottom bide of the steel.
Thermal
lamination was conducted at 204°C on a continuous coil steel lamination
coating process.
I~fter lamination, the two-sided coated steel was cooled, wound into a roll,
and later slit to
2:5 desired widths. The slit narrow web arils were later stamped into
intricately shaped 25 mm
diameter aerosol valve mounting cups t~VMC) using a commercial continuous 14-
station
multidie press. Each of the laminated structures exhibited good formability
and drawability
and no signs of film delarnination. The aerosol valve mounting cups were then
further
converted into aerosol valve assemblies by the addition of a valve, actuator
and stem
30 assembly using a ~rnmercial valve assembly operation.
-17-
tfl~f~~-~~.L..1 AS's~ILS-.~
