Note: Descriptions are shown in the official language in which they were submitted.
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POLYMERS DERIVED FROM ISOBUTYLENE AND FLUORO MONOMER
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present .invention relates generally to
fluoropolymers and thermosetting compositions containing
fluoropolymers. More specifically, the present invention is
directed to fluoropolymers containing functional groups, and
thermosetting compositions that contain functional
fluoropolymers.
2. Description of Related Art
[0003] Coatings.derived from compositions containing
fluoropolymers typically provide good chemical resistance,
weather resistance, and heat resistance. Due to these
properties, interest in using fluoropolymer-based paints has
increased in various areas. For example,
fluoropolymer-containing paints are used as weather resistant
paints in the areas of architecture, automobile, and chemical
engineering. The fluoropolymers used in such paints typically
include a~fluorocarbon monomer, such as
chlorotrifluoroethylene, tetrafluoroethylene,.or vinylidene
fluoride, and another monomer, such as a vinyl ester or a
vinyl ether; usually added to increase the solubility of the
resulting fluoropolymer. w
[0004] As an example, U:S. Patent No. 4,345,057.to Yamabe
et al. discloses a fluoropolymer..having improved curing
~properties..r Coatings using the fluoropolymer reportedly.have
r t
P~'~ritsed ~ 1 x'06' 200. ( . ' DESC ' US0304~9'1
~.,~
k~a~,'s' 'f...,.,..t->,..~~,t..,.:.~k,.". r ~.l ~ . a.
t ' CA 02476099 2004-08-12
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a'glossy finish, good chemical resistance, and good
weatherabi.lity. Also. ATP fl4 004246 discloses a fluoz~.ne-
coiit'aining random copol~er containing (A) 3o-6omol,~., of a .
fluoroolefin monomer, (B) 20-50 rnol~ of a a.l~-e~stituted
olefixl, and (C) 1-S0~ mold of a monomex contair_ing, a
hydrolyzable silyl group. GB 1,121,614 discloses random
copolymers derived from tetrafluoroethylene and essentially
50:5Q molar mixtures~of isobutylene and a second olefinic
monomer. GB 3.,213,17- discloses random copolymer3 coxitai.ning
53-67 wt.~ tetrafluoroethylene, 32-44 wt.~ isobutylene and
0-14 wt.~ of a further copolymerizable.monomer. U.S. Fatent
.No..3,3eo,9~4 to St~.lmar discloses random copolymers of
tetra~fluoroethylene, isobutylene and ethylenically unsaturated
aoids or acid derivatives. U.S. Patent No. 2,4,68,664~to
lIanford et al. discloses random copolymers contairiing 55-BO%
tetrafluoroethy~.ene and i.eobutylene
[OOpS~ In many cases, the durability of a coating, such as
ita weatherability and~or chemical resistance, will depend on
obtaining'an optimum balance~of physical properties, such as
the hardness and flexibility of a Coating film. Generally .
speaking,. obtaining this optimum balance has~been an elusive
goal .
[0006] Moreover, the use of fluoropolymer-aonta~.ning
coating compositions has been limited due to the high cost of
such coatings, due in part to the cost of the fluorocarbon
mOnomerS.
[OpO~~ functional fluoropolymera are typically random
copolymers that indlude functional group-containing aerylic
and/or rnethacxylic monomers. Such a functional fluorogolymer
w~.ll contain a m~.xture of polymer mol ecule~s~having varYin9
individual functional equivalent weight-s and polymer chain
St.ructuxes. In such a copolymer, the functional.groups are
.located randomly along the polymer chain_ Moreover, the
number of functional.groups is not divided equally among the
polymer molecules, such that some polymer molecules may
actually be free of functionality. '
a ~ ~- ~ ~ Emp~fangsZe~it 2,Marz 21.61
0~ 03 X004.
W.
t : a = s' a r '"'a . i t
'rin~~d ' ~ ~ 06, 200'; DErSG;v= . '~S0,30429.1"
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[00081 . Zn a,thermosetting composition, the formation of a .,
~thxee-dimensional crosslinked network is deQendent on the
f~nctional.equivalent weight~as well as the architecture of,
the individual- polYTnex molecules that comprise ~.t ,. Polymer
molecules having,little ox no reactive funCtior~.ality for
-haring functional groups that are unlikely to participate a.n
csogsli~ing reactions due to their locations along the
po~,ymex chain) will contribute little or nothing to the
formation of the three-dimex~.sional crosslinked network _,
resulting in decreased crosslink density and less than optimum
physical properties o~ the finally formed therrnose.t coating.
[00091 It would be desirable to develop fluoropolymer
based thermosetting compositions that are low cost, have a
AiliiEf~l~e~fl ~~~'
Empfa~~szeit 2.Marz 21:51
. . ..
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predictable polymer architecture and provide an optimum
balance of film hardness and~flexibility in~a~durable coating.
SUMMARY OF THE INVENTION
[0010] The present invention,is directed to.a composition .
that imcludes a fluorine-containing copolymer containing at~
least.30 mot 0 of residues having the following alternating
structural unit:
- [ DM-AM ] -
where DM represents a residue from a donor monomer having the
following structure (I):
Rl
( I ) CH2 C\~
~R~
where Rl is linear or branched Cl to C4 alkyl; RZ is selected
from methyl; linear, cyclic or branched Ci to Czo alkyl,
alkenyl, aryl, alkaryl, and aralkyl; and AM represents an
acceptor monomer. The copolymer contains, at least 5 wt.o
fluorine.
[0021] The present invention is also directed to a
composition that includes the copolymer described above, where
the composition contains co-reactive functional groups. . A.
non-limiting example of such a composition is a thermosetting
composition. The present invention is also directed to a~
substrate,~where at least a portion of the substrate is coated
with the thermosetting composition.
[0012]. The present invention is.further directed to a
thermosetting composition that. includes the copolymer
described above,. containing reactive functional groups and at
least one other component-that.contains functional. groups that
are reactive with the functional groups of the copolymer. The
present invention is additionally directed to a.substrate,
where at least a portion of. the substrate is coated with the
thermosetting composition.
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[0013] The present invention is still further directed to
a multi-component composite' coating composition that includes
a base coat deposited from a pigmented film-forming
composition and a substantially pigment free top coat applied
over~at least a portion of the base coat. The base coat
and/or the top coat include one of the~thermosetting
compositions described above. The present invention is~also
directed to substrates where at least a portion of the
substrate is coated with the multi-component composite coating
composition.
DETAINED DESCRIPTION OF THE INVENTION
[0014] Other than in the operating examples, or where
otherwise indicated, all numbers or expressions referring to .
quantities of ingredients, reaction conditions, etc., used in
the specification and claims are to be understood as modified'
in all instances by the term "about." Various numerical ranges
are disclosed in this patent application. Because these
ranges are continuous, they include every value between the
minimum and maximum values: Unless expressly indicated
otherwise; the various numerical ranges specified in this
application are approximations.
[0015] As.used herein, the term "copolymer composition" is
meant to include a synthesized copolymer, as well as residues
from initiators, catalysts, and other elements attendant to
the synthesis of the. copolymer, but not covalenthy
incorporated thereto. Such residues and other elements
considered as part of~the copolymer composition are typically
mixed or co-mingled with the copolymer such that they tend to
remain with the copolymer when it is transferred' between..
vessels or between solvent or dispersion media.
[0016] As used herein, the term "substantially free" is
meant to indicate that a material is present as an incidental
impurity. In, other words, the. material ~ is not interit'ionally .
added to an indicated composition, but may be present at minor
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or inconsequential levels because it was carried over as an
impurity as, part of an intended composition component.
[0017]. The terms "donor monomer" and "acceptor monomer"
are used throughout this application. With regard to the
present iriver~tion, the term "donor monomer" refers to monomers
that have a polymerizable, ethylenically unsaturated group
that has relatively high electron density in the. ethylenic
double.bond, and the term "acceptor monomer" refers to
monomers,that have a polymerizable, ethylenically unsaturated
group that has. relatively low, electron density in the.
ethylenic double,bond.~ This concept has beemquantified to ari
extent by the Alfrey-Price Q-a scheme (Robert Z. Greenley,
Polymer Handbook, Fourth Edition,.Brandrup, Immergut and
Gulke, editors, Wiley & Sons, New York, NY, pp. 309-319
(1999).). All a values recited herein are those appearing in
the Polymer Handbookwnless otherwise indicated.
[00.18] In 'the Q-a scheme, Q reflects the reactivity of a
monomer and a represents the polarity of a monomer, which
indicates the electron density of a given' monomer's
polymerizable; ethylenically unsaturated group. A positive
value for a indicates that a.monomer has a relatively low
electron, density and is an acceptor monomer, as is the case
for malefi c anhydride, which has an,e.value of 3.69. A low or
negative value for a .indicates that.a monomer has a relatively
high. electron density and is a.donor monomer, as is the case
for vinyl ethyl ether, which has an a value of 1.80.
[0019] As referred to herein, a strong acceptor monomer is
meant .tow include those monomers with an,e value greater than
2Ø The term "mild acceptor monomer" is meant to include
thosemonomers with an e.value greater than 0.5 up to and
including those. monomers with an a value of 2.0: Conversely,
the term "strong donor monomer" is meant to include those
monomers with an a value of less than -1.5, and the term "mild
donor monomer" is meant to include those monomers with an a
value of less than 0.5 to those with an a value of -1.5.
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[0020] As used herein and imthe claims, the term
','fluorinated" is used~to describe a material, typically a .
polymer or copolymer, that~contains fluorine atoms.
(0021] The present invention is directed to a composition
that includes a fluorine-containing copolymer. The copolymers
includes at least 30 mol.o,.in many cases at least 40 mol o,
typically at least 50 mol o, in some cases at least 60 mol.fl,
and in other cases at least 75 mol % of residues of the
copolymer derived from alternating sequences of
° donor monomer - acceptor monomer pairs having the.alternating,
monomer residue units of structure: '
- ( DM-~ ~ -
where DM represents a residue from a donor monomer. and AM .
represents a residue from an acceptor monomer. The copolymer
may be a 100% alternating copolymer of DM and AM. .More
particularly,. at least 15 mol o of the copolymer comprises a
donor monomer, which is an isobutylene-type monomer, having .
the.following structure (I):
R1
( I ) CHI C
'R2
where Rl is linear or branched C1 to C9 alkyl;.R~ is one or more
of methyl, linear, cyclic, or, branched C1 to CZO alkyl,
alkenyl, aryl, ahkaryl, and aralkyl. Further, at least
15 mol o of the copolymer includes am acceptor monomer.' The
group Ra may. include one or more functional groups selected
from epoxy, carboxylic acid, hydroxy, thiol, isocyanate,~
capped isocyanate,, amide, amine, aceto acetate, methylol,
methylol ether, oxazoline carbamate, and
beta-hydroxyalkylamide..
[0022] Of note in the present invention, the copolymer
contains at least 5 wt.o fluorine, in some cases at least 10
wt.o fluorine. and in other cases .at least l5 wt.% fluorine,
and up. to 50 wt.o fluorine, in some. cases. up to 40 wt.o
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fluorine,.iw other cases up.to 35 wt.o fluorine and in some
situations up to 30 iat.o fluorine. The copolymer may contain
fluorine in any range of values:inclusive of those~stated
above.' Further,~the copolymer incorporates a substantial
portiowof alternating residues of a mild~donor monomer as.
described by structure I and a mild acceptor monomer.. The.
acceptor monomer will include vinyl monomers having.fluoro
andlor chloro substituents and may include. acrylic acceptor
monomers.
[0023] Thus, the present composition includes the
aforementioned structural unit -[DM-AM]= in the,fluorine-
containing copolymer, in which the structural unit may
specifically include the following structural units (II):
CH2 C---CR~~--CR5
(II)
wherein Rl and R2 are as defined above; R3 is agroup that
includes one or both of chlorine and fluorine and R9 and Rs
are independently selected from H, C1, and F.
[0024] A particular advantage of.the present
fluorine-containing copolymer is its potentially low cost..
[0025] Regarding the donor monomer and acceptor monomer in
the -[DM-AM]- structural unit, a non-limiting list of
published a values for monomers that may be included as donor
monomer and acceptor monomer in the present invention are
shown in Table 2.
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_ g, _
Table 2
Alfrey-Price a values for Selected Monomers
Monomer ~ a value
Monomers of structure 1
Isobutylene ~ -1.20~w
Diisobutylene 0.49
Fluorinated Monomers
Vinyl fluoride 0.72
Chlorotrifluoro .ethylene 1.56:
Tetrafluoro ethylene w 1.63
Acrylic Monomers
Acrylic Acid 0. 881
Acrylamide 0. 541
Acrylonitrile 1. 231
Methyl Acr,ylate 0. 641
Ethyl Acrylate 0. 551
Butyl Acrylate 0. 851
Benzyl acrylate 1. 131
Glycidyl acrylate 1: 281
lPolymer Handbook, Fourth Edition (1999)
~Rzaev et al., Eur. Polym. J., Vol. 24, No. 7,
pp. 981-985 (1998)
[0026]. Any suitable donor monomer may be used in the
present invention. Suitable donor monomers that may be used
include strong.donor monomers and mild donor monomers.~,The
present invention is particularly useful,for preparing v
alternating copolymers where a mild donor molecule is. used:
The present copolymers will include a mild donor monomer
described by structure I, .such as isobutylene and .
diisobutylene, dipentene, isoprenol and 1-octene.,.and.may
additionally include other suitable mild donor monomers. The
mild donor monomer of structure I is pre~serit in.the copolymer
composition at a level of at least l5 mol %, in some cases at
least 25 mol o, typically at least 30 mol o and in some cases.
at least 35 mol %. .The mild donor monomer of structure I is
present in the copolymer composition at a level of up to
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50 mol o, in some cases up to 47.5 mol,o, typically up to~
45 mol o,,and, in some cases, up to 40 mol o. The~level.of.
the mild donor monomer of structure I used is determined by
the properties that: are to be incorporated into the copolymer
composition. Residues from the mild donor monomer of
structure I may bepresent in the copolymer. composition in any
range of values inclusive of those stated above.
[0027] Suitable other donor monomers that may be used:in
the present invention include, but are not limited to,
ethylene,. butene, styrene, substituted styrenes, methyl
styrene, substituted styrenes, vinyl ethers, vinyl esters,
vinyl pyridines, divinyl benzene, vinyl naphthalene, and
divinyl~ naphthalene. Vinyl esters include vinyl esters of
carboxylic acids, which include, but are. not limited to, vinyl
acetate, vinyl butyrate, vinyl 3,4-dimethoxybenzoate, and
vinyl benzoate. The use of other. donor monomers is optional;
when other donor monomers are~present, they are present.at a
level of at least 0.01 moI % of the copolymer composition,
often at least 0.1 mol o, typically at least l mol-o, and, in
some cases, at least 2 mol %. The other donor monomers may be
present at up to 25 mol o,. in some cases up to 20 mol o,
typically up to 10 mol o, and, in some cases, up to 5 mol o.
The level of other donor monomers used is determined by the
properties that are to. be incorporated into the copolymer
composition. Residues from the other donor monomers may be
present in the copolymer composition in any range of values
inclusive of those stated above.
[0028] The copolymer composition includes acceptor
monomers as part of the alternating w
donor.monomer - acceptor monomer units along the copolymer
chain. The.acceptor monomer may includemonomers.having the
structure CR4~=CR3R5, where R3 is a group that includes one or
both of chlorine and fluorine; and R9 and RS are independently
selected from H, C1, and F.
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[0029] Additionally, other suitable acceptor monomers may
be used.Suitable acceptor'monomers include strong acceptor
monomers and mild acceptor monomers. Anon-limiting class of
suitable acceptor monomers are those described by the
structure (III):
( III) CHI CH '
W
where W is selected from the group consisting of -CN, -X; and
-C(=O)-Y,ywherein Y is selected~from the.group consisting. of
-NR3z, -O-RS-O-C (=O) -NR3z, and -OR4; R3 is , selected . from the
group,consisting of.H, linear or branched C1 to Czo alkyl, and
linear or branched C1 .to Czo alkylol; R9 is selected from the
group consisting of H, polyethylene 'oxide), polypropylene
oxide), linear or branched C1 to Czo alkyl, alkylol, aryl and
aralkyl, linear or branched Cl to Czo fluoroalkyl, fluoroaryl
a.nd fluoroaralkyl,.a siloxane radical, a polysiloxane radical,
an alkyl siloxane radical, an ethoxylated trimethylsilyl
siloxane radical, and a propoxylated trimethyl.silyl ~siloxane..
radical; RS is a divalent linear or branched C1 to Czo alkyl
linking group; and X is a halide.
[0030] A class of mild acceptor monomers that may be
included in the present copolymer. composition are acrylic
acceptor monomers. Suitable acrylic acceptor. monomers include
those described by structure (IV):
CHz CH
(IV)
\C-0.
where Y is selected from the group consisting of -NR3z.
-0-R5-O-C (=0) -NR3.z, and -OR4; R3 is selected from the group
consisting of H,. linear or branched Cl. to Czo alkyl, and linear
or branched C1 to Czo alkyl~ol; R4 is selected from the group
consisting, of H,.poly(ethylene oxide), poly(propylene~oxide.),
linear, cyclic, or branched .C1 to.Czo alkyl, alkylol, aryl and
aralkyl, linear or branched Cl..to Czo,fluoroalkyl, fluoroaryl
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and fluoroaralkyl, a siloxane radical, a polysiloxane radical,
an alkyl~siloxane radical, ah ethoxylated trimethylsilyl
siloxane radical, and a propoxylated trime.thylsilyl siloxane
radical;.and RS.is a divalent linear or~branched C1 to CZO alkyl - .
linking group. .... I
[0031]~ Particularly useful types of acrylic acceptor
monomers are those described by structure IV, where Y includes
at least one .functional group of epoxy, carboxylic acid,:
hydroxy, thiol., isocyanate, capped isocyanate, amide, amine,
aceto.acetate, methylol, methylol ether, oxazoline.carbamate,
and/or beta-hydroxyalkylamide..
[0032] Examples of.suitable acceptor monomers include, but
are not limited. to, chlorotrifluoroethylene,
tetrafluoroethylene, trifluoroethylene, difluoroethylene,
binyl fluoride,.hexafluorop.ropyl.ene, and mixtures thereof, and:
optionally further selected from acrylic acid, acrylic acid
esters, acrylamide, N-alkyl substituted acrylamides,
acrylonitrile, hydroxyethyl acrylate, hydroxypr~pyl acrylate,
acrylic, acid, methyl acrylate, ethyl acrylate, butyl acrylate,
isobutyl acrylate, isobornyl acrylate, dimethylaminoethyl
acrylate,.acrylamide, perfluoro methyl ethyl acrylate,
perfluoro ethyl ethyl acrylate, perfluoro butyl ethyl
acrylate, trifluoromethyl benzyl acrylate, perfluoro alkyl
ethyl, acryloxyalkyl~terminated polydimethylsiloxane,
acryloxyalkyl tris(trimethylsiloxy.silane), acryloxyalkyl
trimethylsiloxy terminated polyethylene oxide, chlorotrifluoro
ethylene, glycidyl acrylate, 2-ethylhexyl acrylate, n-butoxy
methyl acrylamide, and.mixtures thereof.
[0033] The acrylic acceptor monomers are present in the
copolymer composition at a level of at least 15 mol o, in. some
cases at least 25 mol o, typically at least 30 mol o, and, in
some cases,. at least 35 mol %. The acrylic acceptor monomers
of structure ITI are present in the copolymer composition at a
level of.up to 50 mol, o, in some Cases up to 47.5 mol o,
typically 'up to 45-mol ~, and;ein some cases, up to 40 mol o.
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The level and type~of acceptor monomers used,is determined by
the properties that are to b~ incorporated into the copolymer
composition. Residues from the~acceptor monomers may be
present in. the copolymer composition in any range of values
inclusive of those stated above..
[0034] Suitable other mild acceptor monomers that may be
used in the present~~invention include, but are:not limited to,
acrylonitrile, methacrylomitrile, crotonic acid,. vinyl alkyl
sulfonates, and ac~olein. The use of other mild acceptor
monomers is optional; when other mild acceptor monomers are.
present, they are present at a level df at.least 0.01 moJ~ o of
the copolymer. composition, often at least 0.1 mol o,~ typically
at least 1 mol %, and, in some cases, at least 2 mol o. The
other acceptor monomers may be present at up to 35 mol %, in
some cases up to 25 mol o, typically up to 15 mol o, and, in
some cases, up to l0 mot %. The level of other acceptor
monomers used is.determined by the properties that are to be
incorporated into the copolymer composition. Residuesfrom .
the other acceptor monomers may be present in the copolymer
composition in any range of values inclusive of those stated .
above.
[0035] The present' copolymer has a molecular weight of at
least 250, in many cases..at least 500, typically at least
1,000, and, in some cases, at least 2,000. The present
copolymer may have a molecular weight of up to 1,000,000, in
many cases up to 500,000, typically up to 10.0,000, and, in
some cases, up to.50,000. Certain applications will require
that the molecular weight of the present copolymer not exceed ..
30,000, in some cases not exceed 25,000, in other cases not
exceed 20,000, and,.in certain instances, not exceed 16,000. v
The molecular weight'of the copolymer is selected based on, the
properties that are to be incorporated_into the copolyme r
composition. The molecular weight of the copolymer may wary
iri any range of~values inclusive of those stated alcove.
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_ 13 _ .
[0036] The polydispersity index (PDIj of the present
copolymer is not always critical.. The polydispersity index of
the copohymer is usually less than 4, in many cases less than
3.5, typically less than 3, and, in some cases, less than 2.5.
As used herein, and in the~~claims, "polydispersity index", is
determined from~the following equation: (weight average..
molecular weight (Mw)/number average molecular weight (Mn)).
A monodisperse polymer has a PDI of 1Ø Further; as used
herein, Mn and Mw. are determined from gel permeation
chromatography using polystyrene standards.
[0037] The copolymer. composition ~f the present invention
may have all of the incorporated monomer residues in an
alternating architecture. A non-limiting example of a .
copolymer segment hawing 1000 alternating architecture of
diisobutylene (DIIB) and hexafluoropropylene (HFP) is shown by
structure V: .
(V)-HFP-DIIB-HFP-DIIB-HFP-DIIB=HFP-DIIB-HFP-DIIB-HFP-DIIB-HFP-
[0038] However, in most instances, the present copolymer
will contain alternating segments and random segments as shown
by structure VI, a copolymer. of D~IIB, HFP, and other monomers,
M:
(VI)
Alternating Alternating
-HFP-DIIB-HFP-DII -M-HFP-M-M-HFP-DIIB-HFP-DIIB-HFP-~HFP-M-
Random Random
[0039] Structure VI shows an embodiment of the present
invention where the copolymer may.include alternating.segments
as shown in the boxes and random segments.as shown by the
underlined segments.
[0040] The random segment's of the copolymer may contain
donor.~or acceptor monomer residues that. have not been
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14 -
incorporated into the copolymer composition by way of an
alternating architecture. Dhe random.segments of the
copolymer composition may further include residues from other
ethyleriically unsaturated monomers.. As recited herein,~all
references to.~polymer segment~s.derived from al erriating
sequences of donor monomer - acceptor monomerpairs are meant.
to include segments of monomer residues such as those shown by
the boxes in structure VI.
[0041] The other ethylenically unsaturated monomers
include .any.suitable monomer not traditionally categorized as
being an acceptor monomer or a donor monomer..: ~,
[0042] The other ethylenically unsaturated monomers,
residue of monomer M of structure VI, is derived from at least
one ethylenically unsaturated, radically polymerizable
monomer. As used herein and in the claims, "ethylenically
unsaturated, radically polymerizable monomer;" and like terms,
are meant to include vinyl monomers, allylic monomers,
olefins, and other ethylenically unsaturated monomers that are
radically polymeri,zable and not classified as donor monomers
or acceptor monomers.
[0043] Classes of vinyl monomers from which M may be
derived include, but are not limited to, monomer residues
derived frorri monomers of the general formula VII:
R11 R12
(VII) ~~ ~ .
R13 R1,4
where Rll, R12, and R14 are independently selected from the group
consisting of H, CF3, straight or branched alkyl of_ 1 to 20
carbon atoms,. aryl, unsaturated straight or branched alkenyl
or alkynyl of 2 to~ l0:carbon atoms, unsaturated straight. or
branched alkenyl of 2 to 6 carbon atoms substituted with a
halogen, C3-Ce cycloalkyl, heterocyclyl and phenyl; R13 is
selected from the group,.consisting of H, C1-C6 linear, cyclic,
or branched alkyl, COORlB, wherein Rl8 ~s selected from the
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group consisting of H, an alkali metal, a Cl to C6 alkyl group,
glycidyl, and aryl. .
[0044] ~ Specific examples of other monomers.; M, that may
be used.in the present invention include methacrylic monomers
and~allylic monomers. Residue of monomer M may be derived ,
from at least one of alkyl methacrylate having from 1 to 20
carbon atoms in the alkyl group. Specific examples of alkyl
methacrylates having from 1 to 20 carbon atoms in the alkyl
group from which residue of.monomer M may be~derived include,
° but are not limited o, methyl methacrylate, ethyl.
methacrylate,.propyl methacrylate, isopropyl, methacrylate,
butyl methacrylate, isobutyl methacrylate, tert-butyl
methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate,
isobornyl methacrylate, cyclohexyl methacrylate, and
3,3,5-trimethylcyclohexyl methacrylate, as well as functional
methacrylates, such as hydroxyalkyl methacrylates, oxirane.
functional methacrylates, and carboxylic acid functional
methacrylates.
[0045] Residue of monomer M may also be selected from
monomers having more than one methacrylate group , for example,
methacrylic anhydride and diethyleneglycol bis(methacrylate).
[0046] As used herein and in the claims, by "allylic .
monomer(s)" what is meant is monomers containing substituted, .
and/or un.substituted allylic.functionality, i.e.,~one or more
radicals represented.by the following.general formula VIIIy
(VIII ) H2C=C (R1°) -CH~-
where Rl° is hydrogen, halogen, or a Cl to CQ alkyl group . Most
commonly, Rl° is hydrogen or methyl,and; consequently, general
formula VIII represents the unsubstituted (meth)allyl radical,
which encompasses both=allyl and methallyl radicals. Examples
of allylic monomers include, but are not limited to,
(meth)allyl alcohol;.(meth)allyl ethers,. such as methyl
(meth)allyl ethers allyl esters of carboxylic. acids, such as
(meth)allyl acetate, (meth)allyl butyrate, (meth).allyl~
.3,4-dimethoxybenzoate, and (meth)allyl benzoate.
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[0047] The present alternating copolymer. is prepared by a
method including the steps wf (a) providing a.domor monomer
composition comprising one-or more donor~monomers of structure
I; (b) mixing an ethylenically unsaturated. monomer composition
comprising.one .or.more acceptor monomers with. (a) to form a.
total monomer composition; and (c), polymerizing the total
monomer composition in the presence of a free radical
initiator. In an embodiment of the present invention, the
ethylenically.unsaturated monomer composition includes
monomers having the structure CR4~=CR3R5 as defined above.
[0048] In °an embodiment of the present'method, the monomer
of structure~I is present at a molar excess based on the
amount of acceptor monomer. Any amount of excess monomer of
structure I may be used in the present invention in order to
encourage the..formation of the desired alternating. .
architecture. The excess amount of monomer of structure I may
be at least 10 mol o, in some cases up to 25 mol o,, typically
up to 50 mol o, and, in some cases; up to 100 mot o based on
the amount of acrylic acceptor monomer. When the molar excess
of monomer of structure I is too high, the process may not be
economical on a commercial scale.
[0049] In a further embodiment o,f the present method,
monomer having the. structure CR92=CR3R5 is present in an amount
of at least l5 mot 0, in some cases 17.5 mol o,.typically at
least 20 mol o, and, in some cases, 25 mol.% of the total
monomer composition:, The.CR42=CR3R5 monomer may further be
present in an amount up to 50 mol o,, in some cases.up'to
47.5 mol %, typically up to 45 mol o, and, in some cases, up
to 40 mol a of~the total monomer composition. The level of
the CR4z=CR3R5 monomer used is determined by the.properties that
are to be incorporated into the copolymer composition. The
CR42=CR3R5 monomers may be present in the monomer composition .in
any range of. values inclusive of .those stated. above.
[0050] The ethyhenically unsaturated monomer composition
of the present method may include other donor monomers as
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described above, as~well as other monomers designated by M and
~.
described.above.. The use of other mild acceptor monomers is
optional in the present method. When other mild acceptor
monomers are present, they are present at.a level of at least
0.01 mol.% of the copolymer composition,.often ~at least
0.1 mol o, typically at least 1 mol o, and, in some cases; at
least 2.mol o of the total monomer composition. The other
acceptor monomers may be present at' up to 35 mol o, in some.
cases upyto 25 mol %,. typically up to 15 moh o, and, in some
cases, up to l0 mol o of the total monomer composition. The
level of other acceptor monomers used herein is determined by
the properties that~are to be incorporated into the copolymer
composition. Residues from the other acceptor monomers may be
present in he copolymer composition in any range of values .
inclusive of those stated above.
[0051] The use of.other monomers, M, is optional in the
present method. When other monomers are present, they are
present at a level of at least 0.01 mol % of the copolymer'
composition, often at least 0.1 mol o, typically at, least
1 mol o, and, in some cases, at least 2 mol %. The other.
monomers may be present at up to 35~mol,o, in some cases up to
25 mol o, typically up to l5 mol o~ and, in some cases, up to
mol %. The.level of other monomers used herein is
determined by the properties that.are to be incorporated. into,
the..copolymer composition.. Residues from the other monomers,.
M, may be present in the copolymer composition in any range of w
values inclusive of those stated above.
[0052].. In an embodiment of the present method, an excess
of monomer of structure I is.used, and the unreacted monomer
of structure I is removed from the resulting copolymer
composition by evaporation. The~removal o.f unreacted monomer
is typically facilitated by the application of a vacuum to the
reaction vessel.
[0053] Any. suitable free radical initiator may be used .in
the present invention. Examples of suitable free_raciical
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initiators include, but are not limited to, thermal free
radical initiators, photo-initiators, and redox.initiators.
Examples of suitable thermal free radical initiators include,
but are not limited to, peroxide compounds; azo compounds, and.
persulfate compounds. .
[0054] Examples of. suitable peroxide compound initiators,
include, but are not limited to, hydrogen peroxide, methyl
ethyl ketone peroxides, benzoyl peroxides, di-t-butyl
peroxide, di-t-amyl;peroxide, dicumyl peroxide,. diacyl.
peroxides, decanoyl peroxides, lauroyl peroxides,
peroxydicarbonates, peroxyesters, dialkyl peroxides,
hydroperoxides, peroxyketals, and mixtures thereof.
[0055] Example's of suitable azo compounds include, but are
not limited to, 4-4'-azobis(4-cyanovaleric acid),
1-1'-azobiscyclohexanecarbonitrile),
2-2'-azobisisobutyronitrile, 2-2'-azobis(2-
methylpropionamidine) dihydrochloride, 2-2'-azobis(2-
methylbutyronitrile), 2-2'-azobis(propionitrile.),
2-2'-azobis(2,4-dimethylvaleronitril,e),
2-2'-azobis(valeronitrile), 2,2'-azobis[2-methyl-N-(2-
hydroxyethyl)propionamide], 4,4'-azobis(4-.cyanopentanoic
acid), 2,2'-azobis(N,N'-dimethyleneisobutyramidine),
2,.2'-azobis(2-amidinopropane).dihydrochloride,.
~2,2'-azobis(N,N'-dimethyleneisobutyramidine) dihydrochloride,
and 2-(carbamoylazo)-isobutyronitrile.
[0056] In.an embodiment of the present invention, the
ethylenically unsaturated monomer composition and the free
radical polymerization initiator are:separately and
simultaneously added to and mixed with the donor monomer
composition. The ethylenically unsaturated monomer
composition and the free radical polymerization initiator may
be added.to the donor-monomer composition over a period of at
least 15 minutes, in some cases~at least 20. minutes, typically
at least 30 minutes, and, in some cases; at least 1 hour. The
ethylenically unsaturated monomer composition and the free
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radical polymerization initiator may further be added to the
donor monomer composition over a period.of up to 24 hours,. in
some case up to l8 hours, typically up to 12 hours,, and, in
some cases, up to 8 hours. The time for adding the
ethylenically unsaturated monomer must.be sufficient to
maintain~a suitable excess of donor monomer. of structure I
over unreacted acrylic acceptor monomer to encourage the
formation of donor monomer - acceptor monomer alternating
segments. The addition time is not so long as to render the
process economically unfeasible on a commercial scale. The
addition time may vary.in any range of values inclusive of
those stated above.
[0057] After mixing, or during addition and mixing,
polymerization of the monomers takes place. The present
polymerization method can be run at any suitable temperature.
Suitable temperature for the present method may be ambient, at
least 50°C, in many cases at least 60°C, typically at least
75°C, and, in some cases, at least 100°C. Suitable'
temperature for the present method may further be described as
being up to 300°C, in many cases.up to 275°C, typically up to
250°C, and, in some cases, up to 225°C. The temperature.is
typically high enough to encourage good reactivity from the
monomers and. initiators employed. However, the volatility of
the monomers and corresponding partial pressures create a~
practical upper limit on temperature determined.by the
pressure rating of the reaction vessel. The polymerization
temperature,may vary in any range of values inclusive of those
stated above.
(0058] The present polymerization method can be run at any
suitable pressure: A suitable.pressure for the present method
may be ambient, at least 1 psi, in many cases at least 5 ps.i,
typically at. least l5 psi, and; in some cases, at least
20 psi. Suitable pressures,for the present method..may further
be described as'being up to 200 psi, in'many cases up to..
175 psi, typically up to 150 psi, and, in.some cases, up to
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125 psi.. The pressure is typically high enough to maintain
the monomers and,initiatorstin a liquid.phase. The pressures
employed have a practical upper limit based on the pressure
rating of the reaction vessel employed. The pressure during
polymerization temperature may vary in any range of values .
inclusive of those stated above.
[0059] The copolymer that. results from the present method
may be utilized as a starting material for the preparation of
other polymers by using functional group transformations by
methods known in the art. Functional groups that can be
introduced by.these methods are epoxy, carboxylic acid,
hydroxy, thiol, isocyanate, capped isocyanate, amide, amine,
aceto acetate, methylol, methylol ether, oxazoline carbamate;
and beta-hydroxyalkylamide.
[0060] For example, a copolymer of the present method
comprising methyl acrylate will contain carbomethoxy .groups:
The carbomethoxy groups can be,hydrolyzed to carboxyl groups
or transesterified with an a~.cohol to form the. corresponding
esterof the alcohol. Using ammonia, the aforementioned
methyl acrylate copolymer can be converted to an amide or,
using a primary or secondary amine, can.be converted to the
corresponding N-substituted amide. Simiharly, using a diamine
such as ethylene diamine, one can convert the aforementioned
copolymer of the present method to an N-aminoethylamide~or,
with ethanolamine, to an N-hydroxyethylamide. The
N-aminoethylamide functionality can be further converted to an
oxazoline by dehydration. The N-aminoethylamide can be
further reacted with a carbonate such,as propylene carbonate.
to produce the corresponding urethane functional copolymer.
These transformations can be carried out to convert all of the
carbomethoxy groups or can be carried out in part,. leaving
some of the.carbomethoxy groups intact.
[0061] - Epoxy groups can be introduced:into the copolymer~~
of tk~e present method directly by using glycidyl acrylate in
the copolymer preparation or indirectly by functional~group
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transformation. One examphe of an indirect method is to
oxidize residual unsaturation in: the copolymer.to epoxy groups
using a peracid such as peroxyacetic acid. Alternatively, one
can.prepare a carboxyl-functional copolymer by~hydrolysis as
described above, treat the carboxyl-functional copolymer with
epichlorohydrin then alkali to produce the epoxy functional
copolymer. These transformations can also be carried out .
exhaustively or in part: The resulting epoxy-functional
copolymer can be further reacted with the appropriate. active
hydrogen containing reagents to form alcohols, amines, or
sulfides.
[0062] Hydroxyl groups can be introduced directly using a
hydroxyl-functional monomer such as hydroxyethyl acrylate in
the copolymer of the present. method, or they can be introduced
by functional group transformation. By treating the
carboxyl-functional copolymer described above with an epoxy ,
one can produce a hydroxyl functional polymer. Suitable
epoxies include, but are not limited to, ethylene oxide,
propylene oxide, butylene oxide, and glycidyl neodecanoate.
[0063] The above-described hydroxyl functional copolymers
can be further reacted to form other copolymers. For example,
a copolymer containing hydroxyethyl groups can be treated, with
a carbamylating agmt, such as methyl carbamate, to produce
the corresponding carbamate functional copolymer. With
diketene or t-butyl acetoacetate, the hydroxyl groups. can also
be converted to acetoacetate esters.
[0064] Isocyanate functional copolymers can also be
produced. Copolymers of.the present method,~which contain 2
or more hydroxyl groups,.can be treated with a diisocyanate
such as isophoronediisocyanate to produce isocyanate-
functional polymers. Primary amine.functional copolymers,
described above; can be phos.genated to produce isocyanate
functionality.
In. an embodiment of the present invention, the composition
contains co-reactive functional groups.
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[0065] In a particularembodimerit, the composition is a'
thermosetting composition. In this~embodiment, the
composition includes the above described alternating copolymer,
and at leas one other component. The, copolymer contains
reactive functional groups and the other component contains.
functional groups that are reactive with the functional groups
of the copolymer.
[0066] In an. embodiment of the present ~mvemlvy, ~li~
functional groups of the copolymer are one or more selected
from epoxy,. carboxylic acid, hydroxy, thiol, isocyanate,
capped,isocyanate, amide, amine, aceto acetate, methylol,
methylol ether, oxazoline carbamate, and
beta-hydroxyalkylamide, and the functional groups. of the other
component are selected from epoxy, carboxylic acid, hydroxy,
thiol, amide, amine, oxazoline, aceto acetate, methylol,.
methylol ether,.isocyanate, capped isocyanate, beta
hydroxyalkamide and carbamate. Typically, the functional.
group equivalent weight of the copolymer is from 100 to
5,000 grams/equivalent and the functional group equivalent
weight of the other material is from 50 to
5,000 grams/equivalent..
(0067] In an embodiment of the present invention, the
thermosetting composition may include additional fluorinated
polymers. The additional fluorinated. polymers may include
functional groups selected from epoxy, carboxylic acid,
hydroxy,.thiol, isocyanate, capped.isocyanate, amide,. amine,
aceto acetate, methylol,.methylol ether, oxazoline carbamate,
and beta-hydroxyalkylamide,.which are reactive with the
functional groups of the other component described above. As
a non-limiting example, the additional fluorinated polymers
may be those described in U.S. Patent No. 4,345','057 to Yamabe
et al., which is herein incorporated by reference. A'
specific, non-limiting example of the additional, fluorinated
polymers that may be used are the ZUMIFZON polymers available
from Asahi Glass Company, Ztd.,.Tokyo, Japan.
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[0068] More particularly, the additional fluorinated
polymers may .include one or~more curable fluor.ocopolymers that
include from 40 to 60 mol o of fluoroolefin units, from 5 to
4~5 mol o of cyclohexyl vinyl ethervunits, from 5 to 45 mol o
of alkyl vinyl ether units, and from 3 to l5, mol o of~
hydroxyalkyl vinyl ether units. Any suitable fluoroolefin
monomers may be used to make the additional curable
fluorocopolymers. Suitable fluoroolefins that may be used
include, but are not limited to, chlorotrifluoroethylene,
tetrafluoroethylene, trifluoroethylene, difluoroethylene,,
hexafluoropropylene and vinyl.fluoride. w
[0069] Typically, in the present thermosetting
composition, the molar or equivalent.ratio of functional
groups in the present alternating copolymer. and, optionally,
the additional curable fluorocopolymers with the functional
groups in the at least one other component is from 0.7:1 to
2:1.~ .
[0070] A particular embodiment of the present invention is
directed to a liquid thermosetting composition that includes
an ungelled copolymer composition that includes the present
fluorine-containing copolymer containing functional groups
and, optionally, the additional curable fluorocopolymers with
functional groups and a crosslinking agent having at least two
functional, groups that are reactive with the functional groups
of the copolymer as the at least one other component.
[0071] In the liquid thermosetting composition, the
functional groups in the fluorinated copolymer are any
suitable functional groups as indicated~above. The
crosslinking agent will have suitable functional groups that
will react with thefunctional groups in thve copolymer.
Suitable functional groups for the crosslinking agent include,
but are not limited to, epoxy, carboxylic acid, hydroxy,
thiol , amide , amme,~oxazoline, aceto acetate, methylol,
methylol ether, isocyanate, capped isocyanate, beta
hydroxyalkamide, and carbamate.
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[0072] The equivalent ratio of functional~groups of .the
cros.slinking agent to~functional equivalents in the , . ,
fluorinated functional copolymer is typically within the range
of 1:3 to 3:1. The crosslinking agent is present in the
liquid,thermosetting composition in an~amount of.from l to 45
percent by weight, based.on.total weight of resin solids, and
the fluorinated.functional copolymer is present in an amount .
of from 55 to 99 percent by weight, based on total weight of
resin solids.
[0073] A non-limiting example of the present liquid .
thermosetting composition is one where the functional group.of
the~fluorinated copolymer is hydroxy and the functional group,
of the crosslinking agent is a capped.polyisocyanate, where
the capping group of the capped polyisocyanate crosslinking
agent is one or more of hydroxy functional compounds,
1H-azoles, lactams, ketoximes, and mixtures thereof. The
capping group may be phenol, p-hydroxy methylbenzoate,~,
1H-1,2,4-triazole, 1H-2,5-dimethyl pyrazole, 2-propanone
oxime, 2-butanone oxime, cyclohexanone oxime, e-caprolactam,
or mixtures thereof. The polyisocyanate of the capped
polyisocyanate crosslinking:agent is one or more of
1,6-hexamethylene diisocyanate, cyclohexane diisocyanate, .
a,oc'-xylylene diisocyanate, a,,a,a',a'-tetramethylxylylene
diiso~cyanate, 1-i.socyanato-3, 3, 5-trimethy.l-5-
isocyanatomethylcyclohe~ane, diisocyanato-dicycloliexylmethane,
dimers of the polyisocyanates, ~or trimers of the
polyisocyanates.
[0074] When the fluorinated copolymer has hydroxy
functionality; it will typically have a hydroxy equivalent
weight of from 100 to 10,000 grams/equivalent.' The equivalent
ratio of isocyanate equivalents in the capped polyisocyanate
crosslinking agent to hydroxy.equivalents in the hydroxy
functional fluorinated copolymer is typically within the range
of 1:3 to 3:1. In this. embodiment, the capped polyisocyanate
crosslinking agent is present in the liquid thermosetting
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composition in an amount of from 1 to 45 percent by weight,
based on total weight~of resin solids, and the hydroxy ~.
functional fluorinated copolymer is present in an amount of
from 55 to 99 percent by weight, based on total weight of.
resin solids. .
[0075] Another non-limiting example of the present liquid
thermosetting composition is one where the fluorinated
copolymer has epoxy.functional groups and the crosslinking
agent is a.carboxylic acid functional compound having from 4
to 20 carbon. atoms.. The carboxylic acid crosslinking agent
may be one or more of:dodecanedioic acid, azelaic acid, adipic
acid, 1,6-hexanedioic acid, succinic acid, pimelic acid,
sebacic acid, malefic acid; citric acid, itaconic.acid, or
aconitic acid.
[0076] A further non-limiting example of the. present
liquid thermosetting composition is one where the fluorinated
copolymer has carboxylic acid.functional groups and the
crosslinking agent is a beta-hydroxyalkylamide compound. The
liquid thermosetting composition may further include a second
polycarboxylic acid functional material selected from the
group consisting of C9 to C2o aliphatic carboxylic acids,
polymeric polyanhydrides, polyesters, polyurethanes, and
mixtures thereof. The beta-hydroxyalkylamide may be
represented by the following structure IX:
( IX)
HO CH CH2' N C E _ N CH2 CH OH'
24 25 25 24 I1
where .Rz4 is H or C1-C5 alkyl; R25 is H, C1-CS alkyl, or a group
having structure X: .
HO ~H CH2
R29.
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for which R~4 is as described above E is a.chemical bond or
monovalent.or polyvalent organic radical derived from
saturated, unsaturated, or.aromatic hydrocarbon radicals
including substituted hydrocarbon~radicals containing. from 2
to.20 carbon atoms; m is 1 or 2; n is from 0 to 2; and m+n is
at least 2.
[0077] The liquid thermosetting composition .of the present
invention is preferably used as a film-forming. (coating)
composition and may contain adjunct ingredients conventionally
used in such compositions. Optiomal ingredients, such as, for
example, plas icizers; surfactants, thixotropic agents;
anti-gassing agents, organic cosolvents, flow controllers,
anti-oxidants, UV light ,absorbers and similar additives
conventional in the art, may be included in the composition.
These ingredients are typically present at up to about.40o by
weight based on. the total weight of resin solids.
[007] The liquid thermosetting composition of the present
invention may be waterborne, but is usually solventborne.
Suitable solvent carriers include the various esters, ethers,
and aromatic solvents, including mixtures thereof, that are
known. in the art of coating formulation. The composition
typically has a total solids content of about 40 to about
80 percent by weight. The liquid therrriosetting compositions
of the present invention will often have a VOC content of less
than 4 percentby weight, typically less than 3.5 percent by
weight and many times less.than 3 percent by weight.
[0079] The liquid thermosetting composition of the present
invention may contain color pigments conventionally used in
surface coatings and may be used as a monocoat, that is, a
pigmented coating. Suitable color pigments include,, for
example, inorganic pigments such as titanium dioxide, iron
oxides, chromium oxide, lead chromate,'and carbon black,.and
organic pigments such as phthalocyanine blue and
phthalocyanine green. Mixtures of the, above mentioned
pigments may also be used. Suitable metallic pigments .
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include, in particular, aluminum flakes, copper bronze flakes,
and metal oxide coated.mica,~nickel flakes, tin flakes, and
mixtures thereof.
[0080] In general,~the pigment is. incorporated into the
coating composition in amounts up to. about 80 percent by--w
weight based on the total weight of coating solids. The
metallic pigment is employed in amounts of. about 0.5 to about
25 percent by weight based on the total weight of coating
solids.
[0081]. In another 'embodiment, the present thermosetting.
composition.is a co-reactable solid, particulate mixture., or
powder of a reactant having at least two functional groups and
a composition including the present fluorine-containing
copolymer having functional.groups, and,.optionally, the
additional curable fluorocopolymers with the functional
groups. In the powder thermosetting composition, the reactant
may have functional groups selected from epoxy, carboxylic
acid, hydroxy, thiol, amide, amine, oxazoline, aceto acetate,
methylol, methylol ether, isocyanate, capped isocyanate; beta
hydroxyalkamide, and carbamate. The functional~groups of the
fluorine-containing .copolymer are those indicated above. The
functional groups of.the reactant will react with the
functional groups in the copolymer.
[0082] The fluorine-containing functional copolymer
typically has a functional group equivalent weight,of from~100
to 5,000 grams/equivalent and the equivalent ratio of reactant
functional groups to functional copolymer functional groups is
within the,range of 1:3 to 3:1: Typically, the reactant is
present in am amount of from l~to 45 percent by weight, based
on total weight ofresin solids; and the functional copolymer
is present in an amount of from 55 to 99 percent by weight,
based on. total weight of~resin solids.
[0083] In an embodiment of the present powder
thermosetting composition, the functional groups of. the
fluorinat~ed.~copolymer are hydroxy functional groups and the
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reactant is a capped polyisocyanate crosslinking agent. In
this embodiment, the capping group of the capped
polyisocyanate crosslinking agent is, one or more of hydroxy
functional compounds, 1H-azoles,.lactams, and.ketoximes. The
capping group is one or more of phenol, p-hydroxy
methylbenzoate, 1H-1,2,4-triazole, 1H-2',5-dimethyl.pyrazo.le,
2-propanone oxime, 2-butanone oxinie, cyclohexanone oxime, and
e-caprolactam. The polyisocyanate of the capped
polyisocyanate crosslinking.agent is one.or more of
1,6-hexamethylene diisocyanate, cyclohexane diisocyanate,
a,a'-xylylene diisocyanate, a,a,a',a'-tetramethylxylylene
diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-
isocyanatomethylcyclohexane, 2,4,4-trimethyl hexamethylene .
diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate,
diisocyanato-dicyclohexylmethane, dimers of said
polyisocyanates, and trimers of the polyisocyanates,.
[0084] The fluorinated.hydroxy functional copolymer
typically.has a hydroxy equivalent weight of from 100 to
10,000 grams/equivalent and the equivalent ratio of isocyanate
equivalents in the capped polyisocyanate crosslinking agent to
hydroxy equivalents in the hydroxy functional copolymer is
within the range of. l:3 to 3:1. Typically, the capped
polyisocyanate crosslinking agent is present in an amount of
from 1 to 45 percent by weight, based on total weight of resin
solids, and the hydroxy functional copolymer is.present in an
amount of. from 55 to 99 percent by weight, based on total
weight of resin solids.
[0085] In another embodiment of the powder thermosetting
composition, the functional groups of the fluorinated
copolymer are epoxy functional groups and the reactant is a
carboxylic functionallreactant having from 4 to 20 carbon
atoms. The carboxylic acid reactant is typically one or. more
of dodecanedioic acid, azela.ic acid, adipic.acid,
1,6-hexanedioic acid, succinic acid, pimelic acid, sebacic
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acid, malefic acid, citric acid, itaconic acid, and aconitic
acid.
[0086] In~a further embodiment of the powder thermosetting
composition, the functional groups of the fluorinated
copolymer are carboxylic functional groups and the reactant is
a beta-hydroa~yalkylamide. In this embodiment, the powder
thermosetting composition may -further include a .second
polycarboxyl.ic acid, typically one or more of CQ to C2o
aliphatic carboxylic acids, polymeric polyanhydrides,
polyesters, polyurethanes, and mixtures thereof. The
beta-hydroxyalkylamide is typically one represented.by
structure IX as detailed above:
[0087] The powder thermosetting composition of the present
invention may also include one or more cure catalysts for
catalyzing the reaction between the crosslinking agent and the
functional copolymer. Classes of useful catalysts .include
metal compounds, in particular, organic tin compounds, and
tertiary amines. Examples of organic tin. compounds include,
but are not limited to, tin(II) salts of carboxylic acids,
e.g., tin(II) acetate, tin(II) octanoate, tin(II)
ethylhexanoate and tin(II) laurate; tin(IV) coiripounds, e.g.,
dibut.yltin oxide, dibutyltin dichloride, dibutyltin diacetate,
dibutyltin dilaurate, dibutyltin maleate, and dioctyltin
diacetate. Examples of suitable tertiary amine catalysts
include, but are not limited to, diazabicycho[2.2.2]octane and
1,5-diazabicyclo[4,3,0]non-5-ene: Preferred catalysts include
tin(II) octanoate and dibutyltin(IV) dilaurate.
[0088] The powder thermosetting composition of, the present
invention may also include pigments and fillers. Examples of
pigments include, but are not limited to; inorganic pigments,
e.g., titanium dioxide.and iron oxides; organic pigments,
e.g., phthalocyanines, anthraquinones, quinacridones, and
thioindigos; and carbon blacks. Examples of. fillers include,
but are not limited to, silica, e.g., precipitated silicas,
clay; and barium sulfate. When used in't~e composition of the
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present invention,~.pigments and fillers are typically present
in amounts of from 0.1 percent to 70, percent by weight, based
on. total weight of the thermosetting composition. More often,,
the thermosetting composition~of the present invention is used
as a clear composition being substantially free of pigments
and fillers.
[0089] The powder thermosetting composition of the present
invention may optionally contain additives.such as waxes for
flow and wetting, flow control agents, e.g.,.
poly(2-ethylhexyl)acrylate, degassing additives such as
benzoin, adjuvant resin to modify and optimize coating'
properties, antioxidants, and ultraviolet (UV) light w
absorbers.. Examples of useful antioxidants and UV light
absorbers include those available commercially.from Ciba-Geigy
under the trademarks IRGANOX and TINUVIN. These optional
additives, when used; are typically present in amounts up to
20 percent by weight, based on total weight of the
thermosetting composition.
[0090] The powder thermosetting composition of the present
invention is typically prepared by first.dry blending the
hydroxy functional polymer, the crosslinkii~g agent, and
additives, such as flow control agents, degassing agents and
catalysts, in a blender,,e:g., a Henshel blade blender. The
blender is operated for a period of time sufficient to result
in a homogenous dry blend of.the materials charged thereto.
The homogenous dry blend is then melt blended in an extruder,
e.g., a twin screw.co-rotating extruder, operated within a
temperature range.of 80°C to 140°C, e.g~, from 100°C to
125°C.
The extrudate of the thermosetting. composition of the present
invention is cooled and, when used as a powder coating
composition; is~typically milled to an average particle size.
of from, for example, 15 to'.30 microns.
[0100] The present invention is also. directed to a method
of coating a substrate, which includes the steps of:
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(A) applying a thermosetting composition to the v
substrate;.
~(B) coalescing the thermosetting composition to
form a substantially continuous film; and
(C). curing the thermosetting composition.
The thermosetting composition is typically.~the liquid
thermosetting composition or powder thermosetting composition
described above. The thermosetting composition includes the
copolymer composition of the present invention, which includes
a functional fluorinated copolymer as previously described arid.
a crosslinking. agent having at least two functional groups .
that are reactive with the functional groups of the functional
copolymer.
[0101] The thermosetting compositions described above can,
be applied to various substrates to which they adhere,
including wood; metals suchas ferrous substrates and aluminum
substrates; glass; plastic, and sheet molding compound based
plastics.
[0102] The compositions can be applied by conventional
means including brushing, dipping, flow coating, spraying,.and
the like, but they are most often.applied by spraying. The
usual.spray techniques.and equipment:for air spraying and
electrostatic spraying and either manual or automatic methods
can be used.. Substrates that may be coated by the method of
the present invention include~.for example, wood, metal,
glass, and plastic
[0103] The thermosetting composition of the present
invention may be applied to the substrate by any.appropriate
means that are known to those of ordinary skill in the art.
The thermosetting composition may be in the.form of a dry
powder or, alternatively, a liquid medirin.. When the substrate
i.s electrically conductive, the. thermosetting composition is
typically electrostatically applied. Electrostatic spray
application generalhy involves drawing the thermosetting
composition from a fluidized bed and propelling it through a
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corona field. The particles of the thermosetting. composition
become charged as they pass~through the~corona field,.and are
attracted to and deposited upon the electrically conductive
substrate;, which, is grounded, As the charged particles begun
to build up; the substrate becomes insulated, thus limiting
further particle deposition. This insulating phenomenon
typically limits the film build of the deposited composition
to a.maximum of 3 to 6 mils (75 to 150 microns).
[0104] Alternatively, when'the~substrate is not
electrically conductive, .for example, as is the case with many
plastic substrates, the substrate is typically preheated prior
to application of the thermosetting composition. The
preheated temperature of the substrate is equal to or.greater
than that of the melting point of the thermosetting
composition, but less than its cure temperature. With spray
application over preheated substrates film builds of the
thermosetting composition in 'excess of 6 mils (150 microns)
can be achieved, e.g:, 10 to 20 mils (254 to 508 microns).,
[0105] When the thermosetting composition is a liquid, the
composition is allowed to coalesce to form a substantially
continuous film on the substrate. Typically, the film
thickness will be about 0.01 to about 5 mils (about 0'.254 to
about 127 microns), preferably about 0.l to about 2. mils
(about 2.54 to about 50.8 microns) in thickness. The film is'
formed on the surface of the substrate by driving solvent,
i.e., organic solvent and/or water,, out of the film by heating
or by an air drying period.. Preferably, the heating will only
be for a short period of time, sufficient to ensure that any
subsequently applied coatings can be applied to the film
without dissolving the composition. Suitable drying
conditions will depend on the particular composition but, in
general, a drying time of from about 1 to 5 minutes at a
temperature.. of about ,68-250°F (20-121°C) will be adequate.
More than one coat of the composition may be applied to
develop the~optimum appearance. Between coats, the previously
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applied coat may be flashed, that is,, exposed.to ambient
conditions for about 1 to 20 minutes.
[0106] After application to the substrate, the
thermosetting composition is,then coalesced to .form a
substantially continuous film. ~~Coalescing of the applied
composition is generally achieved through the application of
heat at a temperature .equal to or greater than that of. the
melting point of the composition, but less than its cure
temperature. In the case of preheated substrates, the
application and coalescing steps can be achieved in
essentially one step.'
[0107] The coalesced thermosetting composition 1s next
cured by the application of heat. As used herein and in the
claims, by "cured" is meant a three-dimensional crosslink
network formed by covalent bond formation, e.g., between the
free isocyanate groups. of the crosslinking agent and the
hydroxy groups.of the polymer. The temperature at which the
thermosetting composition of the present invention cures is
variable and depends in part on the type and amount of
catalyst used. Typically, the thermosetting composition has a
.cure temperature within the range of 130°C to 160°C, e.g.,
from l40°C to 150°C.
[0108] In accordance with the present invention, there is
further provided a.multi-component composite coating
composition that include s a base coat layer deposited from a .
pigmented film-forming composition; and a substantially
pigment free top coat applied over at least a portion of the
base coat:. Either the base coat or.the top coat or both coats'
may include the liquid thermosetting composition or the powder
thermosetting composition describedabove. The multi-
componer~t composite coating composition as.described herein is
commonly~referred to as a color-plus-clear coating
composition..
[0109] ~The.pigmented film-forming composition from which
the base coat is deposited can b,e any of the compositions
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useful in coatings applications,~particularly automotive
applications in, which color~plus-clear coating compositions
are extensively used. Pigmented film-forming compositions
conventionally comprise a~resinous binder and a~pigment to act
as a colorant. Particularly useful resinous binders are
acrylic polymers, polyesters. including alkyds, polyurethanes,
and the copolymer composition of the present invention.
[0110]. The resinous binders for the pigmented film-forming'
base coat composition can. be organic solvent-based materials,
such as those described in U.S. Patent No. 4,220,679, note
column 2, line 24 through columri.4, line 40. Also, water-
based coating compositions such as those described in U.S.
Patent Nos. 4,403,003, 4,147,679, and 5,071,904~can bewsed as
the binder imthe pigmented film-forming composition.
[0111] The pigmented film-forming base coat composition is
colored and may also contain metallic pigments. Examples of
suitable pigments caw be found in U.S. Patent Nos. 4,220,679,
4,403,003, 4,147,679, and 5,071,904
[0112] Ingredients that.may be optionally present in the
pigmented film-forming base coat composition are those which
are well known in the art of formulating surface coatings and
include surfactantsy flow control agents, thixotropi.c agents,
fillers, anti-gassing agents, organic co-solvents,. catalysts,
and other customary auxiliaries. Examples ~of these optional
materials and suitable amounts are described in the
aforementioned.U.S. Patent Nos. 4,220,679, 4,403,003,
4,147,679; and 5,071,904:
[0113]. The pigmented film-forming base coat compositiow
can be applied to the substrate by any of the. conventional
coating techniques, such as brushing, spraying, dipping, or
flowing, but are most often applied by: spraying. The usual
spray techniques and equipment for air. spraying, airless
spraying, and electrostatic spraying employing either manual
~or automatic methods.can be used. The pigmented film-forming
comp~sit'ion is applied in~an amount sufficient to provide a .
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base coat having a film thickness typically of 0.1 to 5 mils
(2.5 to 125 microns) and preferably 0.l to.2 mils (2.5 to 50
microns). .~ .
[0114] After deposition of the pigmented film-forming base
coat composition onto the substrate, and prior to application
of the substantially pigment free top coat, the base coat can
be cured or alternatively dried. In drying the deposited base
coat, organic solvent and/or water is driven out of the base
coat film by heating or the passage of air over its surface.
Suitable drying conditions will depend on the particular base
coat composition used and on the ambient humidity in: the case..
of certain water-based compositions: In general, drying of
the deposited.base coat is performed over a period of from 1
to 15 minutes and at a temperature of 21.°C to 93°C.
[0115] The substantially pigment free top coat is. applied
over the deposited base coat by'any of the methods by which
coatings are known to be applied. In an embodiment of the
present invention, the~substantially pigment free top coat is .
applied by electrostatic spray application as described
previously herein. When the substantially pigment free top
coat 'is applied over a deposited base coat that has been
dried, the two coatings can be co-cured to form the multi-
component composite coating composition of the present
invention. Both the base~coat and top coat are heated
together to conjointly cure the two layers. Typically, curing
conditions of 130°C to 160°C for a period of 20 to 30 minutes
are employed. The substantially pigment free top coat .
typically has a thickness within the.range of 0.5 to.6 mils.y
(13 to 150 microns), e.g., from 1 to 3 mils (25 tow75
microns)..
[0116] The present invention is more particularly .
described in the following examples, which are.intended to be'
illustrative only, since numerous modifications and'variations
therein will be apparent to those skilled in the art. Unless
otherwise specified, all parts and percentages are by weight.
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Example 1-3
[0117]. These examples demonstrate the.synthe,sis o.f the .
present fluorinated alternating copolymer. 'The following ..
ingredients were used in the polymerizations:,
Ingredients Example Example Example
1 2 3
Charge 1 ,
Diisobutylene 10008 '
Isobutylene 10008 10008
Aromatic 1001 5008 5008
Charge 2 .
Di-t-amyl peroxide 728 608 308
Charge 3 6678 2508
Cyclohexyl methacrylate
Butyl Acrylate 170.98
Hydroxyethyl acrylate 341.88 5008 2508
Charge 4
Chlorotrifluoro ethylene 2228 5008 5008.
Solids 63.6 wt.o 67.8 wt.% 62.0 wt.o
Molecular Weight
Mw ~ . 2, 910 4, 001
Mn 1,285 1,622
Mw/Mn 2.3 2.5
1 ExxonMobil Chemical company, riouszon, la
[0118] Charge l was added to a reaction flask equipped
with an'agitator, a thermocouple,,and a nitrogen inlet. The
flask was sealed, the solution was placedW nder a nitrogen
blanket,.and heated to 130°C.. Charge 2 was then added to the
reactor over a 2.5-hour period. Fifteen minutes after the
Charge.2 addition was begun, Charges 3 and 4 were added
simultaneously to the reactor over a 2-hour period: During
the monomer addition, the 'temperature in the reactor was
maintained at 130-150°C and pressure of about 130 psi for ..
diisobutylene and about 400 psi for isobutylene. After
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Charges 2, 3 and 4 were added, the reaction mixture was held
for 2 hours at 150°C. The reactor was then cooled to 25°C.
Gas chromatography analysis of the reaction mixture showed
that. all of the acrylates were reacted. The. reported solids
of the resulting polymer were, determined at.110°C for one
hour. The reaction flask was then equipped for simple vacuum
distillation and the.reaction mixture heated to 155°C to~
remove the unreacted diisobutylene or isobutylene. The
vacuum-stripped resins were subsequently used to prepare
coating compositions. The molecular weight was determined by
geI permeation chromatography using polystyrene standards.
Example 4-6 ~.
[0119 Coating compositions were prepared using the
following ingredients:
Ingredients Example Example Example
4 5 6
Component 1.
Resin, Example 1 151g
Resin, Example 2 175.8g
Resin, Example 3 181.6g
Shepard black pigment
9.9g 11.88 11.98
Cobalt aluminate blue
pigment 52.98 63.18 63.58
Sherwood green pigment
4.6g 5.5g 5.5g
Titanium dioxide 5.9g 7.Og 7.Og
hexamethylene diisocyanate
76.78 101.88 97.Og.
Component 2
dibutyltin dilaurate 1.68 2 .2'8 2.18
UV absorber 5.18. 6.88 6.58
Hindered Amine 4.98 6.68 6.28
light stabilizers
Polybutylacrylates 1.68 2.28 2.18
aromatic,hydrocarbon6
23.18 31.68
' CYSORB 1164, Cytec Tndustries
4 SANDUVOR 3055 available from Clariant International Limited, London, U.K.
..BYIC 322 available from BYK Chemie Division of ALTANA.AG, Bad Homburg,
Germany
6 ExxonMobil Chemicals
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[0120] The resins were charged to a paint can.and the
various p.ignients were added in the order indicated with .
mixing. The mixture was then added to a mixing mill and
milled with a zircoa media until a Hegman.grind of 7+ was
obtained. This formed component one of a two-component
composition: Component two was prepared by adding the rest,of
the ingredients.in the order indicated to a.second vessel and
mixing to form a homogeneous mixture. The two components were
kept separate until immediately before application.
[0121] The coating compositions were applied to.both a
galvanized steel substrate and an aluminum substrate as shown
in the table below. The coatings were cured at the
temperature and time indicated in the table. The dry film
thickness in mils is also reported iri the table. After cure,
the 60° gloss, T-bend flexibility, pencil.hardness, reverse
impact strength, and resistance to methyl ethyl ketone solvent
was determined. The 60° gloss, was measured with a 60° gloss
meter from Byk-Gardner Instrument Company.
[0122] The. T-bend test was evaluated for loss of adhesion
and for cracking after the coated panel was bent to varying
degrees.. The first number indicates the diameter of the bend
is so many times the thickness of the steel panel. For
example, a "3" indicates that the diameter of the bend was
three times the thickness of the steel panel before loss of
adhesion was indicated. Zoss of adhesion was~determined by
pressing a piece of adhesive tape down onto the film surface
and then. quickly ripping the tape from the film.. The second.
number was a subjective number related to cracking. The
rating was assigned on a scale of 7. to 9. A score~of 9
indicated no cracking and no film removal with .the tape, while
a score of 0 indicated severe~cracking and complete film
removal by the tape.
[0123] ,The pencil hardness is a measure of the resistance
~of the coating to a pencil indentor. The,pencil. hardness .
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scale begins with 4B, which indicates a relatively soft
coating, and increases to 10H, which indicates a relatively:
hard coating. The scale reads~as follows: 4B, 3B, 2B, B, HB,
F, H,~2H, 3H up to 10H.. The coating was indented with pencils
of increasing hardness until. the pencil scratched or etched
the surface.
[0124] . The reverse impact resistance was determined by
subjecting the cured coatings to 60 inch-pounds of reverse
impact according to ASTM D2794. The impacted films were
observed visually for the amount of cranking and for removal
of the film after apiece of adhesive~tape was pressed down
onto the film surface and then quickly ripped from the film.
The results were given a pass (P) or.fail (F) rating with P
indicating no cracking and no film removal with the tape,
while F would indioate cracking and/or film removal.
[0125] The solvent resistance test was done with methyl
ethyl ketone (MEK). A cloth was.~saturated with MEK and rubbed
back and forth (double rub) until the coating was marred (MEK
Mar value) and until the coating was removed from the
substrate (MEK Number, a value of.100 indicates that the
coating was not. removed). The values in the Table are from
double rubs.
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Ex. Ex. Ex. Ex. 10 Ex. 11
7 8 9
Coating Ex. Ex. Ex: MEGAFLON DURANAR'
4 5 6 5522
GLAVANIZED SUBSTRATE
Cure Temperature (F) 465 465 465' 465 465
Cure Time (seconds) 20-30 20-30 20-30 20-30 20-30
Dry Film Thickness 0.75- 0.75- 0.75- 0.75- 0.75-
(mils) 0.85 0.85' 0.85 0.85 0.85
60 Gloss 56.7 67.6 76.4 71.4 29.6
T-Bend 0/4 3/5+ 2/3 0/5+ 0/5+
Pencil Hardness ~ 2H H F H F
Reverse Impact P P, P P , P
Resistance
MEK Mar 2 2 2 1 2
MEK Number 100 100 100 100 100
ALUMINUM SUBSTRATE
Cure Temperature (F) 465 465 465 465 465.
Cure Time (seconds) 20-30 20-30 20-30 20-30 20-30
Dry Film Thickness 0.75- 0.75- 0.75- 0.75- 0.75-
(mils) 0. f5 0.85 0.85 0.85 0.85
60 Gloss 53.3 48.8 57.6 49.0 21.8
T-Bend 2/3 3/5 3/5+. 0/2 0/0
Pencil Hardness 2H 2H 2H H H
.
Reverse Impact F F P P P.
Resistance
' Available from PPG Industries, Pittsburgh, PA, includes.LUMIFLON LF552,
Asahi Glass Ltd., Tokyo, Japan
Available from PPG Industries
[0126] The~data demonstrate the excellent balance of film
hardness and flexibility, as well as the durability of
coatings derived from hermosetting comp~sitions. containing
the present.fluorine-containing copolymer.
[0127] The present invention has been described with
reference to specific details of particular embodiments
thereof. It is not intended that such details be regarded as
limitations upon.the scope of the invention except insofar as
and to the ex~tent.that,they are included in the accompanying
claims.
