Note: Descriptions are shown in the official language in which they were submitted.
WO 94~11122 2 1 ~ 7 8 3 0 PCr/US93/10791
TITLE
WATER-BORNE COMPOSITIONS
COMPRISING HALF E~STERS OF ANHYDRIDE
POLYMERS CROSSLINKED BY EPOXIES
FIELD OF THE INVENTION
This invention is related to a multi-component water-borne
coating composition co~ -ising a half-ester of an an_ydride polymer and
an epoxy crocclinkin~ agent.
BACKGROUND
There are a wide variety of multi-component coating
compositions available for finiching automobiles and trucks. Various
co~ting compositions comprising anhydride or epoxy con~ining
compositions are knowvn. For example, U.S. Patent 4,906,677 discloses a
composition colll~lisillg an acrylic anhydride polymer, a glycidyl
component, and a phosphonillm catalyst. U.S. Patent 3,136,736 and British
patent 994,881 disclose coating compositions COlll~liSillg polyepoxides and
maleic anhydride copolymers. U.S. Patent 4,732,791 concerns a coating
2 0 composition comprising a polyepoxide, a monomeric anhydride curing
agent, and a hyd~o~yl cont~ining polyfunctional polymer.
U.S. patent no. 4,906,677, in column 4, lines 40-47, licclQses
that anhydride polymers, in epoxy-anhydride compositions, may be
COllvt;l ~ed to a half-ester by alcohol solvents.
2 5 European Patent Application, publication no. 0 353 734 A2,
published 07.02.90 and European Patent Application, publication no. 0 450
963 A1, published 09.10.91 both ~ ose the combination of a polymer
having a half-esterified acid anhydride group and a compound having an
epoxy group and a hydroxy group, or a separate epoxy and hydro~y
3 o compound. These patents teach that, in such compositions, high
temperature curing is required in order that the half-esteriffed acid
anhydride groups are ring-closed to produce acid anhydride groups which
then react with hydl o~yl groups, which in turn release carboxyl groups
which then react with the epoxy groups. These patents indicate that a
3 5 certain hydroxy equivalent number or hydroxy value is necessary for
adequate water resistance of the coating composition.
W O 94J11122 ~ 1 47 ~3 ~ PC~r/US93/10791
.
The afore-men~io~e-l EP 0 353 734 A2 states that water can
be used as a "diluent" if the carboxyl groups are neutralized with an amine.
In contrast, the present invention is directed to compositions in which r
water is employed as the primary carrier, organic solvents being possible
diluents. The afore-mentioned EP 0 450 963 A1 states that the half
esterified polymer may be neutralized with amines to make a hydrophilic
polymer which can form an aqueous composition. The examples, however,
all tlicclose compositions which employ organic solvents.
A problem with present co~tinE compositions for
lo automobiles and trucks, or parts thereof, is that durability is not as good as
desired. An important aspect of durability is environmental resict~nçe. The
present invention offers a high quality finish exhibiting superior
e,lvho~".,en~l resistance at lower cost. This is particularly notewolLlly
given the fact that the present composition is a waterborne finish.
The present composition is a multi-package system, having
use in automotive finishes for new automobiles and for r~finish, for use in
maintenance, and for use in both high temperature and low temperature
cured systems. Such a coating composition exhibits excellent clarity,
appearance and environmental r~ict~n~e Importantly, such compositions
z o offer a low voC (volatile organic content) since the binder is waterborne
employing an aqueous (primarily water) carrier.
SUMMARY OF THE INVENTION
The present invention is directed to a co~ting composition
2 5 co~ g 20-80% by weight of binder components and 80-20~o by weight
of an aqueous carrier which is primarily water. The binder contains
(a) a half-ester of an anhydride polymer having at least two
anhydride groups and having a weight average molecular
weight of about 2,000-100,000;
3 o (b) an epoxy component having at least two reactive glycidyl
glOU~S; and
(c) a basic compound to neutralize the half ester.
Optionally, these compositions may also include epoxy-silane
polymers, silane polymers, acid polymers, lower molecular weight polyester
35 or polyester urethanes, melamine resins, hydroxyl polymers, acrylic latices,
waterborne urethane emulsions or dispersions, and combinations thereof.
WO 94/11122 21~ 7 ~ 3 0 PCr/USs3/10791
In one embodiment, the water content of the aqueous carrier is greater
than 60 percent by weight of the aqueous carrier.
- The present invention is also directed to a process in which
applicant's composition is applied to a substrate as an automotive topcoatl.
DETAILED DESCRIPIION OF THE INVENT~ON
The composition of the present invention forms a durable
ellviro~ ental resi~t~nt coating. The composition is especially useful for
m~intenence coating of architect~lral structures and for finishing the
exterior of ~lltomobiles and trucks.
The composition can also be pigmented to form a colored
finish, although the composition is particularly useful as a clearcoat.
Preferably, the co~ting composition has a high solids content
and contains about 20-80~o by weight binder and 20-80% by weight
aqueous carrier. The binder of the composition contains about 25-90~o,
preferably 35 to 65% (by weight of binder) of the half-ester of an anhydride
polymer cont~ining at least two anhydride groups; 5-50%, ~refe,ably 15 to
30~o (by weight of binder) of a glycidyl or epoAy cont~ining component.
Optionally, the composition may comprise 5-50~o, preferably
2 0 10 to 25% by weight of binder of an acrylic or a polyester or polyester
urethane which may contain hydroAyl and/or acid functionality. If hydluAy
functional, the hydl oAy number is 20 to 120. If acid functional, the acid
number is 20 to 120.
In the present composition, when used in a baking system, if
2 5 an optional acrylic or polyester or polyester urethane polymer is acidfunctional, then the cure occurs between the acid groups and the epoAy
groups and the half ester groups,following ring-closure during baking, and
the epoAy group. Some cure may also occur between the acid of the half
ester and the epoAy. The main cure, however, is based on the ring closure
3 o during baking.
The anhydride polymer employed in preparing the present
composition has a weight average molecular weight of about 2000-100,000,
determined by gel permeation chromatography using polymethyl
methacrylate as a standard. Preferably the anhydride polymer has a weight
3 5 average molecular weight of 3,000-50,000.
WO94/11122 2~ ~ 830 PCr/USs3/10791
The anhydride polymer may be prepared by conventional
techniques in which the monomers, solvent, and conventional catalysts such
as t-butyl perbenzoate are charged into a polymerization vessel and heated
to about 75-200C for about 0.5-6 hours to form the polymer.
The anhydride acrylic polymer is preferably an acrylic
copolymer formed by polymerizing a mixture of monomers comprisiong
alkyl methacrylates and/or alkyl acrylates, where the alkyl groups have 1-12
(preferably 1-8) carbon atoms, and ethylenically ~ms~ rated anhydrides (or
ethylenically unsaturated dicarboxylic acids which are con~el led to the acid
anhydride during the polymerization). Optionally, the anhydride acrylic
polymer can cont~in other components such as styrene, methyl styrene,
acrylonitrile, and/or methacrylonitrile in amounts of about 0.1-50% by
weight.
Typical alkyl acrylates and methacrylates that can be used to
form the anhydride acrylic polymer are methyl methacrylate, ethyl
methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate,
hexyl methacrylate, octyl methacrylate, decyl methacrylate, lauryl
methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
octyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, and the like, or
2 0 any others ment;oned below. Other components that can be used to form
the anhydride acrylic polymer are acrylamide, methacryl~mide and acrylo
alkoxy silanes such as g~mm~- methacryloxyl propyl trimethoxy silane.
Also, the anhydride acrylic polymer can contain about 0.1-5% by weight of
an ethylenically lm~ lrated acid such as acrylic acid, methacrylic acid,
2 5 itaconic acid, maleic acid, and the like.
Typically useful ethylenically lm~ rated anhydrides are
itaconic anhydride, maleic anhydride, isobutenyl s~lc~inic anhydride, and
the like. As stated above, it is also possible to impart the anhydride
functionality to the anhydride acrylic polymer by using an ethylenically
3 0 lln~ rated dicarboxylic acid which conver.s to the acid anhydride during
the reaction. Suitable ethylenically lm~ lrated dicarboxylic acids that can
be used are itaconic acid, maleic acid, isobutenyl succinic acid, and the like.
A preferred anhydride acrylic polymer comprises styrene,
butyl methacrylate, butyl acrylate, and itaconic anhydride. Another
3 5 preferred polymer co~ lises methyl methacrylate, butyl acrylate, and
WO 94/11122 2 1 ~ 7 ~ ~ ~ PCI/US93/10791
itaconic anhydride. Another preferred polymer comprises styrene,
isobornyl methacrylate, butyl acrylate, and maleic anhydride.
The anhydride polymer is half-esterified with an alcohol.
Suitable alcohols inrlllde methanol, ethanol, propanol, butanol;
ethyleneglycol monoalkyl ether, dialkylaminoethanol, in which particularly
c~mmon alkyl groups are methyl and ethyl; acetol, allyl alcohol, propargyl
alcohol, tetrahydrofurfuryl alcohol; and the like. The reaction to produce
the half-ester is generally at ambient or elevated temperatures, suitably in
the range of 20 to 150C. Such a reaction may be conducted in the
o presence of a catalyst, for example, tertiary amines such as triethyl~mine,
quaternary ~mmonillm salts such as benzyltrimethyl ammonium chloride,
and the like.
For utility in the aqueous carrier, the anhydride polymer,
after it is converted to the half-ester, is neutralized with a base. Suitable
bases inchl~le amines which are volatile under the conditions of cure.
Typical amines are triethyl amine, trimethyl amine, ~mmor~ and dimethyl
eth~nol~mine. Other bases inrl~lde sodium hydroxide, pot~csillm hydroxide
and the like. The base is suitably used in the amount of 0.1 to 10 percent
by weight of binder to solublilize or disperse the half ester in the aqueous
2 o carrier.
The epoxy component preferably C~lt~ at least two
glycidyl groups and can be an oligomer or a polymer. Typical glycidyl
co",l~onents are sorbitol polyglycidyl ether, m~nnitol polyglycidyl ether,
pentaelylhlilol polyglycidol ether, glycerol polyglycidyl ether, low
2 5 molecular weight epoxy resins such as epoxy resins of epichlorohydrin and
bisphenol A, di- and polyglycidyl esters of acids, polyglycidyl ethers of
iso-;y~nulates, such as Denecol EX301'19 from Nagase. Sorbitol polyglycidyl
ethers, such as DCE-358~ from Dixie Chem. Co., and di- and polyglycidyl
esters of acids, such as Araldite CY-184'l9 from Ciba-Geigy or XUS-71950~9
3 o from Dow Chemical form high quality finiches. Cycloaliphatic epoxies such
as CY-179~ from Ciba-Geigy may also be used. For ambient cure refinish
applications, generally the choice of epoxy is chosen for room temperature
reactivity and the extent of cure with the half ester. (Ambient curing
means that the composition cures at 10 to 90C, preferably 15 to 60C
3 5 within a couple of weeks, preferably one week.)
W094/t~ 0 PCr/us93/l079l
Glycidyl methacrylate or acrylate cont~ining acrylic polymers
can be used, such as random and block polymers of glycidyl
methacrylate/butyl methacrylate. The block polymers can be prepared by
anionic polymerization or by group transfer polymerization. Optionally,
the composition may further comprise a copolymer having both epoxy and
alkoxy silane groups, prepared as the re~ction product of epoxy monomers
such as glycidyl methacrylate and silane monomers as described below.
Optionally the present composition may co~ lise a silane
polymer as a separate additional ingredient or component. Such silane
polymers may suitably have a weight average molecular weight of about
100~30,000, a number average molecular weight of about 500 10,000. (All
molecular weights disclosed herein are determined by gel permeation
chromatography using a polystyrene standard.)
As indicated above, the binder of the present composition
may comprises from about 5 to 50%, preferably 10 to 25%, based on the
weight of the binder, of an acrylic or polyester or polyester urethane or
copolymer thereof having a ll~dlo~ number of about 20 to 120, preferably
70 to 100, or an acid number of about 20 to 120, preferably 75 to 95. This
polymer has a weight average molecular weight of about 2,000 to 20,000,
plcfelably 4,000-10,000. Unless otherwise indicated, all molecular weights
mentioned herein are measured using gel permeation chrom~tography
using polymethyl methacrylate as a standard.
Polyester urethanes are a reaction product of a llydro~yl
le. "~ te~ polyester component and a polyisocyanate component,
preferably, an aliphatic or cycloaliphatic diisocyanate. The polyester, which
may be used alone or as a component of the polyester urethane, may be
suitably prepared from linear or branched chain diols, in~ lin~ ether
glycols, or ll~ixlures thereof or ~ ufes of diols and triols, cont~ining up to
and in~lntling 8 carbon atorns, or mixtures of such diols, triols, and
3 o polycaprolactone~polyols, in combination with a dicarboxylic acid, or
anhydride thereof, or a ll~i~lllre of dicarboxylic acids or anhydrides, which
acids or anhydrides cont~in up to and inch-~ling 12 carbon atoms, wherein
at least 7S~ by weight, based on the weight of dicarboxylic acid, is an
aliphatic dicarboxylic acid.
3 5 Representative saturated and -n~t--rated polyols that can be
reacted to form a polyester include alkylene glycols such as neopentyl
WO 94/11122 214 7 8 3 0 PCI/US93/10791
glycol, ethylene glycol, propylene glycol, butane diol, pentane diol,
1,6-hexane diol, 2,2-dimethyl-1,3-dioxolane-4-methanol, 1,4-cyclohexane
dimethanol, 2,2-dimethyl 1,3-propanediol, 2,2-bis(hydroxymethyl)propionic
acid, and 3-mercapto-1,2-propane diol. Preferred are 1,6-h.oY~n~-liol and
butylene glycol.
Polyhydric alcohols, having at least three hydroxyl groups,
may also be inclllcled to introduce br~n~hing in the polyester. Typical
polyhydric alcohols are trimethylol propane, trimethylol ethane,
pentaelyLh~ilol~ glycerin and the like. Trimethylol propane is preferred, in
forming a branched polyester.
Polycaprolacone polyols may be also be used in m~king the
polyester. A preferred polycaprolactone, a triol, is Tone~9 FCP 310
(available from Union Carbide).
The carboxylic acids used in m~king the polyester component
of the polyester urethane include the saturated and nn~tllrated
polycarboxylic acids and the derivatives thereof. Aliphatic dicarboxylic
acids that can be used to form the polyester are as follows: adipic acid,
sebacic acid, snccinic acid, azelaic acid, dodecanedioic acid, 1,3 or 1,4-
cyrloh~Y~ne dicarboxylic acid and the like. A preferred acid is adipic acid.
2 o Aromatic polycarboxylic acids include phthalic acid, isophthalic acid,
terephthalic acid, and the like. Anhydrides may also be used, for example,
maleic anhydride, phthalic anhydride, trimellitic anhydride, and the like.
Typical polyisocyanates that may be used to form the
polyester ulelha-le are as follows: isophorone diisocyanate which is
2s 3-isocyanatemethyl-3,5,5-trimethyl- cyclohexyl-isocyanate,
propylene-1,2-diisocyanate, butylene-1,2-diisocyanate,
butylene-1,3-diisocyanate, hexamethylene diisocyanate,
methyl-2,6-diisocyanate, methyl-2,6-diisocyanate caproate, octamethlyene
diisocyanate, 2,4,4-trimethylheY~methylene diisocyanate, nonamethylene
3 o diisocyante, 2,2,4-trimethylh~oY~methylene diisocyanate, decamethylene
diisocyanate, 2,11-diisocyano-dodecane and the like, meta-phenylene
diisocyanate, para-phenylene diisoxyanate, toluene-2, 4-diisocyanate,
toluene-2,6-diisocyanate, xylene-2, 4-diisocyanate, xylene-2,6-diisocyanate,
dialkyl benzene diisocyanates, such as methyl~ro~ylbenzene diisocyanate,
3s methylethylbenzene diisocyanate, and the like: 2,2'-biphenylene
diisocyanate, 3,3'-biphenylene diisocyanate, 4,4'-biphenylene diisocyanate,
W O 94~11122 2 1 4 7 8 3 0 PC~r/US93/10791 ~
~ .
..
3,3'-dimethyl~,4'-biphenylene diisocyanate, and the like;
methylene-bis(4-phenyl isocyanate), ethylene-bis(4-phenyl isocyanate),
isopropylidene-bis(4-phenyl isocyanate), butylene-bis(4-phenylisocyanate),
and the like; 2,2'-oxydiphenyl diisocyanate, 3,3'-oxydiphenyl diisocyanate,
4,4'-oxydiphenyl diisocyanate, 2,2'-ketodiphenyl diisocyanate,
3,3'-ketodiphenyl diisocyanate, 4,4'-ketodiphenyl diisocyanate,
2,2'-thiodiphenyl diisocyanate, 3,3'-thiodiphenyl diisocyanate,
4,4'-thiodiphenyl diisocyanate, and the like; 2,2'-sulfonediphenyl
diisocyanate, 3,3'-sulfonediphenyl diisocyanate, 4,4'-sulfonediphenyl
lo diisocyanate, and the like; 2,2,-methylene-bis(cyclohexyl isocyanate),
3,3'-methylene-bis(cyclohexyl isocyanate), 4,4'-methylene-bis(cyclohexyl
isocyanate), 4,4'-ethylene-bis(cyclohexyl isocyanate),
4,4'-propylene-bis-(cyclohexyl isocyanate),
bis(paraisocyano-cyclohexyl)sulfide, bis(para-isocyano-cyclohe~yl)sulfone,
bis(para-isocyano-cyclohexyl)ether, bis(para-isocyano-cyclohexyl)diethyl
silane, bis(para-isocyano-cyclohexyl)diphenyl silane,
bis(para-isocyano-cyclohexyl)ethyl phosphine oxide,
bis(para-isocyano-cyclohexyl)phenyl phosphine oxide,
bis(para-isocyano-cyclohexyl)N-phenyl amine,
2 0 bis(para-isocyano-cyclohexyl)N-methyl amine, 3,3 '-dimethyl-4,4 '-diisocyano biphenyl, 3,3'-dimethoxy-biphenylene diisocyanate,
2,4-bis(b-isocyano-t-butyl)toluene,
bis(para-b-isocyano-t-butyl-phenyl)ether,
para-bis(2-methyl4-isocyanophenyl)benzene, 3,3-diisocyano ~m~ns~ne,
3,3-diisocyano bi~ m~nt~ne, 3,3-diisocyanoethyl-1'-bi~ m~nt~ne,
1,2-bis(3-isocyano-propoxy)ethane, 2,2-dimethyl propylene diisocyanate,
3-methoxy-he~methylene diisocyanate 2,5-dimethyl heptamethylene
diisocyanate, 5-methyl-nonamethylene diisocyanate,
1,4-diisocyano-cyclohtoY~ne, 1,2-diisocyano-octadecane,
2,5-diisocyano-1,3,4-l~Y~ 7Qle, OCN(CH2)30(CH2)20(CH2)3NCO,
OCN(CH2)3NCO or the following:
OCN(CH2)3 IN(CH2)3NC
CH3
WO 94/11122 2 1 ~ 7 8 3 0 PCI/US93/10791
Aliphatic diisocyanates are preferred, forming urethanes that
have excellent weatherability. One aliphatic diisocyanate that is
particularly preferred is trimethyl hexamethylene diisocyanate.
A preferred polyester urethane is the re~ction product of
trimethylhexamethylene diisocyanate and a hydroxy termin~te~l polyester of
1,3-butylene glycol, 1,6-hexanediol, adipic acid, trimethylolpropalle, and
Tone'19 FCP 310.
It is noted that a hydro~y functional polyester urethane can
be collvel led to the corresponding acid functional polyester urethane by
0 reaction with methylhexahydropthalic anhydride or other mono-anhydride
such as succinic anhydride. Converting the hydroxy to the acid may result in
longer pot life in the clearcoat.
A polyester may be prepared by conventional techniques in
which the component polyols and carboxylic acids and solvent are esterified
at about 110C-250C for about 1-10 hours to form a polyester. To form a
polyester urethane, a diisocyanate may then be added and reacted at about
100C for about 15 mimltes to 2 hours.
In preparing the polyester urethane, a catalyst is typically
used. Collvelllional catalysts inrl~lcle benzyl trimethyl ammonium
2 o hydro~ide, tetramethyl ~mmQnillm chloride, organic tin compounds, such
as dibutyl tin diaurate, dibutyl tin oxide stannous octoate and the like,
i.",. complexes and litharge. About 0.1-5% by weight of catalyst, based
on the total weight of the re~ct~ntc, is typically used.
The stoichiometry of the polyester preparation is controlled
2 5 by the final hydroxyl number and by the need to obtain a product of low
acid number; an acid number below 10 is preferable. The acid number is
defined as the number of milligrams of pot~ccinm hydroxide needed to
neutralize a one gram sample of the polyester. Additional inform~tion on
the preparation of polyester urethanes is disclosed in commonly ~ccigned
3 o U.S. Patent No. 4,810,759, hereby incorporated by reference.
Another optional component are acrylic latices such as
Neocryl~ available from ICI. Other latices are available from ICI and
Rohm & Haas. Another optional component are urethane dispersions or
emulsions such as Neorez~ 9699 and the like from ICI or Spensol L,52
from Reichold. Other suppliers are Witco, American Cy~n~mitl, and
wO 94/11122 2 ~ 47 83 ~ pcr/uss3t1o79l
Sanncor. Such dispersions include polyethers, polyesters, polycarbonates,
or combinations thereof.
An acid resin is optionally added to the coating composition
The acid functional material can be formed by polymerizing monomers of
alkyl methacrylates, or alkyl acrylates or mixtures thereof, where the alkyl
groups have 1-12 carbon atoms and ethylenically lln~hlrated acids.
Optionally, the acid functional polymer can also contain other components
such as styrene, methyl styrene, and/or acrylonitrile, methacrylonitrile in
arnounts of about 0.1-50% by weight.
Typical alkyl acrylates, methacrylates, and other components
that can be used to form the acid functional polymer are the same as those
listed above with respect to the anhydride polymer
Typically useful ethylenically lln~t~lrated acids are acrylic
acid, methacrylic acid, itaconic acid, maleic acid, and the like.
This acid resin may also contain hydro~yl functionali~r by
using monomers such as hydro~yethylacrylate, hydroxyethyl methacrylate
and llydrol~yl~lo~l acIylate~ The hydroxy functionality may be introduced
by a post reaction of the acid with epoxy co~ g co~ mds such as
Cardura EZ9 from Shell Chemical Company (a glycidyl ester of versatic
2 o acid) and propylene oxide.
Another optional component of the present composition is
the half ester of an anhydride compound, as distin~ hed from a polymer,
for example the reaction product of an acid anhydride such as
hexahydlop~halic anhydride or a sllcrinic anhydride, which may be
substihlte~l, for example with a Cl-Cg alkyl group, with a monofimction~l
or polyfunctional alcoholic solvent such as methanol or ethylene glycol. A
prefel~ed half ester is the reaction product of methylhexahydrophthalic
anhydride and an alcohol such as ethylene glycol. Other alcoholic solvents
are ~,lopallol, isobutanol, isopropanol, tertiary butanol, n-butanol,
3 o propylene glycol monomethyl ether, ethylene glycol monobutyl ether, and
the like. The half ester is suitably present in the amount of 2 to 25 percent
by weight of binder, preferably 4-12 percent.
About 0.1-8~o ~preferably 0.5 to 5~o) by weight, based on the
weight of the binder of the coating composition, of a catalyst is added to
3 5 enhance curing of the composition. For refinish (ambient cure systems),
typical catalysts are as follows: tertiary amines such as triethylene rli~mine~
WO 94/11122 21 ~ 783~ PCr/US93/10791
.
11
quinuclirline, dialkyl alkanol amines such as dimethyl ethanol~mine diethyl
ethanol amine, dibutyl ethanol amine, diethyl hexanol amine, triethylamine
bisdimethylaminoethyl ether (available from Union Carbide),
diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, and the
like, lithinm tertiary butoxide, tri(dimethylaminometnyl)phenol,
bis(dimethylamino)propan-2-ol, N,N,N ,N -tetramethylethylene~ mine,
N-methyldiethanol~mine N,N-dimethyl-1,3-propane~ mineand
1-dimethylamino-2-propanol. Tertiary amines and bicyclic tertiary amines
are preferred catalysts. For baking systems, typical catalysts are as follows:
0 triethylene ~ mine, quinuclidine, dialkyl alkanol amines such as dimethyl
ethanol~mine, diethyl ethanol amine, dibutyl ethanol amine, diethyl
hexanol amine and the like, lithium tertiary butoxide, tri(dimethyl-
~minomethyl)phenol, bis(dimethylamino)propan-2-ol,
N,N,Nl,Nl-tetramethylethylene~ mine, N-methyldiethanol~mine,
15 N,N-dimethyl-1,3-prop~nedi~mine and 1-dimethylamino-2-propanol or
quaternary ~mmonillm salts such as tert-butyl ammonium bromide, benzyl
trimethyl ~mmonillm formate and the like. Preferred catalyst, howt;ver, are
phosphonium compounds such as are disclosed in U.S. Patent No.
4,906,677, hereby incorporated by reference in its entirety.
2 o Typical solvents used to prepare the anhydride acrylic
polymer or used as a diluent for the coating composition inclll~le toluene,
xylene, butyl ~cet~te~ butyl proprionate, ethyl benzene, higher boiling
aromatic hydrocarbons, amyl acetate, ethyl acetate, propyl acetate,
ethylene or propylene glycol mono alkyl ether acetates.
2 5 The solvent for the final composition, as sold or applied,
comprises primarily water. Suitably at least 60 percent of the liquid carrier,
preferably 70 percent is water. Preferably deionized water is employed.
Optional diluents for the water inclnde butyl acetate, butyl proprionate,
mono- and di- ethers of proplyene glycol, and butyl cellosolve.
3 o Generally, the present composition is applied as a co~ting to
a substrate by conve~llional techniques such as spraying. The composition
may be applied as a multi-package system. Multi-package means that at
least some of the components are kept separate until shortly before their
application. For instance, the glycidyl component must be kept seperate
3 5 from the half ester and optional acid components. For refinish systems, the
reslllting coating can be dried and cured at elevated temperatures of 5 to
WO 94/11122 . PCI/US93/10791
21~7~3~
12
90C, preferably 15 to 60C. Coatings are applied to form a finish typically
about 0.5-5 mlls thick, and preferably 1-2 mils thick. For OEM (orgiginal
equipement m~nllf~ctllre) automotive applications, the co~ting can be
dried and cured at elevated temperatures of 100 to 200C.
To i~ rove weatherability of the clear finish of the coating
composition, about 0.1-5%, by weight, based on the weight of the binder, of
an ultraviolet light stabilizer or a comhin~tion of ultraviolet light stabilizers
can be added. These stabilizers inclllcle ultraviolet light absorbers,
screeners, quenchers and speci~lc hindered amine light stabilizers. Also,
0 about 0.1-5~o by weight, based on the weight of the binder, of an
antioxi~l~nt can be added.
Typical ultraviolet light stabilizers that are useful are listed in
U.S. patent no. 4,906,677, previously incorporated by reference.
Particularly useful ultraviolet light stabilizers that can be used are hindered
aII~ines of piperidyl derivatives such as those .licl~los~d in Murayama et al.,
U.S. Patent 4,061,616, issued December 6, 1977, colurnn 2, line 65, through
colum~ 4, line 2, and nickel compounds such as
[l-phenyl-3-methyl4-decanoylpyr~Ql~te(S)]-Ni,
bis[phenyldithiocarbamato]-Ni(II), and others listed in the above patent,
2 o col~lmn 8, line 44 through line 55.
An applicable blend of ultraviolet light stabilizers comprises
2-[2'-hydroxy-3',5'-1(1-1-dimethyl-propyl)phenyl]benzotrizole and
bis-[4-(1,2,2,6,6-pen~mell,ylpil)eridyl)] 2-butyl-2-[(3,5-~-butyl-4-hydroxy-
phenyl)methyl] propanedioate. Although the stabilizers can be employed
in any ratio, a 1:1 ratio of benzotriazole to propanedioate is preferred.
The composition can be applied over a pigmented or colored
basecoat finish. For refinish compositions, if over a waterborne basecoat,
the basecoat is typically first allowed to dry. For original automotive
production, the coating composition is applied over a waterborne basecoat
3 o and baked at conventional curing temperatures in the art, typically 265F.
Before applying the topcoat, however, the waterborne basecoat is typically
dried using a warm-air flash or bake, without substantially curing the
basecoat, in order to remove a substantial amount of the water. l~uring
baking, the half-esterified acid anhydride groups are believed to convert
3 5 back to the original acid anhydride ring groups. These groups then react
wO 94~11122 2 1 4 7 ~ 3 0 ~ Pcr/US93/10791
with the epoxy groups. A composition with a relatively faster acting epoxy
cro~linker may be employ
Basecoats suitably comprise collvenLional pigments,
optionally metallic flake or the like, which can be made using convelllional
techniques in which a mill base cont~ining pigment, dispersant and solvent
or carrier is first formed.
The coating composition for refinish applicatons can be
applied over both solvent- and water borne basecoats.
The present composition can be pigmented to form a colored
lo finish such as a primer, basecoat, monocoat, or maintenence paint. About0.1-200 percent by weight, based on the weight of the binder, of
co~lve~l ior~l pigments can be added using conventional techniques in
which a mill base con~ining pigment, dispersant and carrier is first formed.
The mill base is then mixed with the composition to form a colored
composition.
The following examples illustrate the invention. All parts
and percentages are on a weight basis unless otherwise indicated. The
weight average molecular weight of polymers was determined by GPC (gel
permeation chromatography) using polyethyl methacrylate as a st~n~i~rd~
unless stated otherwise.
EXAMPLE 1
This example illustrates the preparation of a half ester of a
maleic anhydride polymer, specifically the half ester of a styrene/isobornyl
2 5 methacrylate/ butyl acrylate/maleic anhydride copolymer. The anhydride
polymer was first prepared, as follows. To a reactor, heated to reflux,
equipped with a condensor, stirrer, nitrogen purge, feed system, he~ting
mantle, were added, as Part I, 1384.86 parts of bulylplopionate. The
following Part II was premixed and then fed to the reactor over four hours.
3 o The next following Part III was added to thc reactor over 30 min~ltes~ held
for 30 mimltes.
Parts by
Part II We;~ht
Styrene monomer 1081.92
Isobornyl methacrylate 735.71
Butyl acrylate 1773.05
W O 94~11122 214 7 8 3 0 PC~r/US93/10791
Maleic anhydride 735.71
Butyl propionate 2077.29
Tertiary butyl peroxyacetate 259.66
Parts by
Part III Wei~ht
Tertiary butyl peroxyacetate 19.04
Butyl proprionate 138.Q0
TOTAL 8205.24
After the 30 minute holding period, a total of 1090 parts by
weight of solvent is stripped off, resulting in a yield of 7115.24 parts by
weight.
The product polymer had a Gardner-Holdt viscosity of V and
a measured solids of 62.84%. ~he actual molecular weight was measured
by gel permeation chromatography to be Mn = 23s5 and M W = 6135.
This maleic anhydride polymer was then coverted to a a
methyl half ester by mixing the following components;
2 0 Components Parts
Maleic anhydride polymer solution (prepared
as described above) 600
Methanol 24
2 5 The first component was heated to 50C and the methanol componentadded over a 2~30 minute period. The mixlllre was then heated to 75-
85C for five hours or until the anhydride band in the infrared analysis has
disappeared (90-95~o gone).
3 0 EXAMPLE 2
This example illustrates an epoxy silane polymer, more
particularly an epoxy functional acrylo~ ne polymer which was prepared
by cha~h~g the following constit~lent~ into a polymerization vessel
equipped with a heating m~ntle reflux condenser, thermometer, nitrogen
inlet, and stirrer:
WO 94/11122 2 1.4 7 8 3 0PCI/US93/10791
Portion 1 Parts by Weight
Xylol (135-145C) 363.2
Aromatic 100 363.2
Portion 2
Styrene 530.9
Gamma-Methacrylo~y~ro~yl trimethoxy silane 1380.3
Methyl methacrylate 318.5
Butyl methacrylate 79.6
0 2-Ethylhexyl acrylate 79.6
Glycidyl methacrylate 265.4
Aromatic 100 40.9
Xylol 40.9
Portion 3
t-Butyl peroxyacetate 132.7
Aromatic 100 99.6
Xylol 99.7
TOTAL 3794.5
Portion 1 was charged into the polymerization vessel and
heated under nitrogen to 149C. Portion 2 was then added over 360
mimltes and Portion 3 was added over 420 min~ltes to the vessel. The
reslll~in~ polymer solution had the following characteristics:
2 5 Gallon wt.(lbs/gal) 8.56
% wt. solids 72.2
~o volume solids 68.6
Mv~ of polymer 5000
Mn Of polymer 1650
The polymer composition was, by weight, 20 percent styrene,
52 percent g~"""~-methacrylo~lplo~yl trimethoxy silane (A-174 from
Union Carbide), 12 percent methyl methacrylate, 3 percent butyl
methacrylate, 3 percent 2-ethylhexyl acrylae, and 10 percent glycidyl
3 5 methacrylate, which may be represented as follows: S~Y/A-
174/MMA/BMA/2-EHA/GMA in the ratio of 20 / 52 / 12 / 3 / 3 / 10.
W O 94/11122 2 ~ 4 7 g 3 ~ PC~r/US93/10791
EXAMPLE 3
This example illustrates, as an optional component for a
composition according to the present invention, a polyester urethane
solution which may be prepared by charging the following con~tih1ents in
order into a reaction vessel equipped with a stirrer, a he~tin~ source and a
reflux condenser:
Parts by
Portion 1 Wei~ht
o 1,3-butylene glycol 173.4
1,6-hexanediol 163.1
Trimethylol propane 78.8
Adipic acid 403.7
Toluene 20.0
Portion 2
Propylene glycol monomethyl ether acetate294.4
Port;on ~
Tone'19 FCP 310 (caprolactone polyol 934.9
from Union Carbide)
2 o Propylene glycol monomethyl ether acetate185.3
Hydrocarbon solvent 706.1
Portion 4
trimethylh~-Y~methylene diisocyanate 290.3
dibutyl tin dilaurate 0.5
2 5 Portion 5
Hydrocarbon solvent 69.8
Total 3320.3
Portion 1 is charged in order into the reation vessel, and the
3 0 co~ ents of Portion 1 are heated to distill water at 140-230C. The
distillation is contin~le-l until the acid number is 6.5 to 8.5. The product is
thinned and cooled to 98 to 102C by charging Portion 2 into the vessel.
While the constituents in the vessel are m~int~ined at the above
temperature, Portion 3 was charged to the reactor in order. Portion 4 is
added to the composition at a unirollll rate over a 30 minute period while
WO 94/11122 2 1 4 7 8 3 0 PCr/US93/10791
the batch temperature is m~int~ined at 98-102C. A sample is removed
and tested for unreacted isocyanate NCO by infrared analysis. The
composition is held at the above temperature until there is no unreacted
isocyanate in the composition. Portion 5 then is added as a rinse and the
resulting composition was allowed to cool to ambient temperatures.
Following this procedure, the resulting composition had a
polymer weight solids content of about 61.0%. The polyester urethane had
a Gardner-Holdt viscosity of L The Mn (number average molecular
weight) was 3734.0 and the Mw (weight average molecular weight) was
o 7818.0 (by gel permeation chromatography using polystyrene as the
st~nrl~rd). The acid content was determined to be 4.9 Meq/g. The lydlo~y
number was 92.
EXAMPLE 4
This example illustrates, as another optional component for
use in the present composition, an acid polymer, more specifically a
methacrylic acid resin,which may be prepared by charging the following
col~Liluents into a reactor equipped with a thermometer, stirrer, dr~ g
funnel, and con~le-n~or:
2 o Parts by
Portion 1 We;~ht
Propylene glycol monomethyl ether acetate155.3
(hereafter PM acetate)
Xylene 103.5
2 5 Portion 2
Butyl methacrylate 174.8
Methacrylic acid 97.1
Butyl acrylate 140.8
Styrene 72.8
3 o Portion 3
Tertiary butyl peroxy acetate 35.0
PM acetate 41.7
Xylene 27.8
Total 849.0
WO 94~lll22 ~ 8 3 ~ Pcr/us93/lo7
18
Portion 1 was charged into the reactor and heated to reflux
(a~ploxi",~tely 140C). Portion 2 was premixed and added to the reactor
dropwise over a 240 minute period. Portion 3 was pren~ixed and added to
t_e reactor over a 270 minute period concurrent with Portion 3. After the
addition was complete, the reactor was held at reflux and filled out.
The resnltin~ acid polymer composition had a composition of
15% styrene, 36% butyl methacrylate, 29% n-butyl acrylate, and 20%
methacrylic acid. The solids conten~ was 60% and the polymer had a
Gardner-Holdt viscosity of Z1. The polymer had a weight average
molecular weight of 5000.
EXAMPLE 5
This example illustrates a waterborne refinish clearcoat
composition accordillg to the present invention, using a methyl half ester of
maleic anhydride and an epoxy cros~linker. The following components were
thoroughly blended:
Parts by
Part 1 Wei~ht
2 o Methyl half ester of maleic anhydride
acrylic polymer (as prepared above) 35.39
Deioni7ed water 48.91
Triethyl amine 4.19
DCE 358 (Sorbitol epoxy from Dixie Co.) 8.9
DABCO (25% triethylene ~ mine in butanol) 2.61
When the composition was thinned with water and cast as a
film on glass, the film cures at ambient temperature. The coating was
virtually tack free in al,proxi",~tely S hours. After 24 hours. the solvent
3 o resi~t~nce (to MEK) was measured to 17 double rubs. After 5 days the
solvent resict~nce (to MEK) was measured to 100+ double rubs.
This composition can be fortified with TINUVIN 1130 and
TINUVIN 292 (or TINUVIN 123) light stabilizers to give durable films, the
level of the former at 2-3% on binder and the level of the latter at 1-2% on
binder.
WO 94/11122 2 ~ 47 ~ 3 0 Pcr/US93/10791
EXAMPLE 6
This example illustrates a waterborne clearcoat composition
based on latex and a maleic anhydride half ester copolymer. The following
components were thoroughly blended:
Parts by
Part 1 Wei,~ht
Methyl half ester of maleic anhydride
acrylic polymer (as prepared above but88.0
34% solids in water/butyl proprionate,
neutralized with triethylamine)
Deionized water , 77.0
Diethylene glycol monobutyl ether 4.4
Propylene glycol monomethyl ether 4.4
IINUVIN 1130 UV stabilizer 2.1
(benzotriazole adduct from Ciba-Geigy)
TINUVIN 292 free radical stabilizer 1.4
(hindered amine from Ciba-Geigy)
DEHYDRAN 1620 defoamer
(from Henkel) 0.1
~lTON GR-7M wetting agent 0.2
(from Union Carbide)
NEOCRYL A6015 acrylic emulsion latex
(45% solids in water from ICI) 66.6
triethylene ~ mine catalyst (25% in
water) 4 3
DCE-358 aliphatic epoxy cros~linker
(sorbitol polyglycidol ether from
Dixie Chem. Co.) 10.0
3 o TOTAL 258.5
The reslllting coating composition had a solids content of
29% and its c~lc~ ed VOC is 2.3 lb/gal. The above clear coating
composition was drawn over glass plates and allowed to cure for seven days
3 5 at ambient temperature. The reslllting clearcoat had good clarity and gloss,
WO94~1l122 21~783~ pcr/us93/1o79l
and exhibite a Persoz hardness of 193 and an MEK solvent resistance of 59
double rubs.
EXAMPLE 7
This example illustrates four different compositions (A
through D) based on an anhydride half ester and an epoxy, with and
without an ~ rly polyurethane. With respect to each of the
composi~ioll~ A through D, respectively, the following components were
thoroughly blended:
A B C D
(Parts by (Parts by (Parts by (Parts by
~NGREDIENT we;pht) weight) wei~ht) we;~ht)
PART 1
Maleate half ester 68.73 66.61 18.67 17.45
Deionized H20 94.97 92.04 25.79 24.11
Triethylarnine 8.13 7.88 2.21 2.06
Urethane dispersion 1
2 o (NEOREZ~ XR9679) 0.00 0.00 138.09 0.00
Urethane dispersion 2
(NEOREZ'19 XR9699) 0.00 0.00 0.00 129.06
Butyl carbitol 0.00 0.00 0.00 14.20
TINUVIN~ 1130 1.97 2.15 2.22 2.13
TINUVIN~292 1.31 1.44 1.48 1.42
DEHYDRAN surfactant 0.10 0.10 0.10 0.10
DOWANOL PM surfactant 2.22 0.02 2.96 3.60
TRlTON'i9 surfactant 0.20 0.20 0.20 0.20
Diethlyene triamine catalyst
3 o (25~o) in H20 5.08 4.93 1.38 1.29
PART 2
Epoxy (XUGY 358) 17.28 14.78 4.14 4.39
Epoxy (ARALDlTE CY184) 0.00 9.85 2.76 0.00
3 5 TOTAL 200.00 200.00 200.00 2.00
WO 94/11122 2 1 ~1 7 ~ 3 0 PCI/US93/10791
Part 1 was premixed in order slowly and Part 2 was added with mixin~. The
final compositions A through D exhibited the following properties.
TheoreticalSolids 32.75 35.89 36.98 35/52
TheoreticalVOC 2.90 2.60 :2.40 2.40
Viscosity
Zahn #2 71(3) 65(4) 65(4) Very High
Viscosity
ICI Cone and Plate¢250 CPS175 CPS 155 CPS 225 CPS
Persoz Hardness 1 Day
Glass 120 60
Chroma Base* 76 57
Persoz Hardness 3 Day
Glass 125 59 107 134
Chroma Base 76 54 53 64
Persoz Hardness 7 Day
Glass 265 198 232 202
Chroma Base 114 91 103 118
MEK Re.ci~t~nce (Double Rubs)
Glass 100+ 100 100+ 100+
Chroma Base 50 37 100+ 30
Tukon Hardness
33 Days 6.30 2.98 2.71 1.60
Hardness Viscosity
Overnight Gelled Gelled Gelled Fluid
*Chroma Base is a registered trademark for a solventborne basecoat
commercially available from Du Pont Co.
Based on the above results, it is evident that the addition of
an ~nxili~ry polyurethane provides greater strength and hardness. However,
3 5 with polyesterurethane, using the less reactive epoxy (ether epoxy) in
Wo 94J11122 2 1 4 7 ~ 3 0 pcr/us93/1o79l
composition C resulted in better properties than using the more reactive
epoxy in composition D.
EXAMPLE 8
This example illustrates a clearcoat composition according to
the present invention, using a methyl half ester of maleic anhydride and an
epoxy cro.c.clinker. The following components were thoroughly blended:
Parts by
Part 1 Weight
lo Methyl half ester of maleic anhydride
acrylic polymer (as prepared above) 27.0
Deionized water 59.8
Triethyl amine 2.7
XU-71950 (Diglycidyl ester from Dow) 6.4
TINUVIN 1130 (UV screener3 O.S
Catalyst solution 2.2
TINUVIN-123 (25%) in butyl cellosolve 1.4
In the above list, the catalyst solution refers to a solution of
benzyl triphenyl phosphonium chloride (10%) in isopropanol. The
TINUVIN-123 is a hindered amine; both TINUVINs are commercially
available from Ciba-Geigy.
The coating composition was sprayed onto primed metal
panels coated with a waterborne basecoat and cured at 265F. The coating
exhibited excellent hllmitlity resistance, chemical resistance, durability and
other film properties.
EXAMPLE 9
This example illustrates another clearcoat composition
accoldhlg to the present invention, using a methyl half ester of maleic
anhydride and an epoxy crosslinker, but also with a silane component. The
following components were thoroughly blended:
Parts by
Part 1 Wei~ht
Methyl half ester of maleic anhydride
WO 94/11122 21:4 7 8 3 0 pcr/us93/lo791
acrylic polymer (as prepared above) 17.79
Deionized water 68.02
Triethyl amine 1.94
XU-71950 (Diglycidyl ester from Dow) 4.22
Epoxy silane polymer (as prepared above)3.95
TINUVIN 1130 (UV screener) 0.4
TINUVIN 123 (25% in butyl cellosolve) 1.05
Catalyst solution 1.71
Butyl cellosolve 0.92
TOTAL 100
In the above list, the catalyst solution refers to a solution of
benzyl triphenyl phosphonium chloride (10%) in isopropanol. The
TINUVIN 123 is a hindered amine commercially available from Ciba-
Geigy.
This clear is adjusted to spray at 32 sec in a #2 Zahn cup
with deionized water. The pH equals 9.2. The clear is sprayed over a
waterborne basecoat and cured at 265-285F for 30 minntes The reslllting
films were hard, glossy, and recict~nt to solvent and hnmi(lity. These films
2 o are durable and enviromnentally resict~nt
Various modifications, alterations, additions, or substitutions
of the components of the composition of this invention will be apparent to
those skilled in the art without departing from the scope and spirit of this
2 5 invention. This invention is not limited to the illustrative embodiments set
forth herein, but rather the invention is defined by the following claims.
