Acrylic oligomeric and polymeric durability enhancing agents, method therefore and cured coating compositions containing the same

A durability enhancing agent comprising the reaction product of an acrylic oligomer or acrylic polymer and an ultraviolet light absorbing compound, a hindered amine light stabilizer or mixture thereof, said durability enhancing agent further comprising more than one carbamate functional group, or group convertible to a carbamate group, and optionally, including other reactive functionality capable of undergoing a crosslinking reaction. Also included is a curable coating composition comprising the durability enhancing agent, a method for obtaining a coated substrate and the coated article obtained thereby.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to acrylic ultraviolet light absorber and 
hindered amine light stabilizer compounds, method therefore and coating 
compositions containing the same, wherein the compounds include a 
carbamate functionality. 
2. Discussion of the Prior Art 
Curable coating compositions such as thermoset coatings are widely used in 
the coatings art. They are often used for topcoats in the automotive and 
industrial coatings industry. Color-plus-clear composite coatings are 
particularly useful as topcoats where exceptional gloss, depth of color, 
distinctness of image, or special metallic effects are desired. The 
automotive industry has made extensive use of these coatings for 
automotive body panels. Color-plus-clear composite coatings, however, 
require an extremely high degree of clarity in the clearcoat to achieve 
the desired visual effect. High-gloss coatings also require a low degree 
of visual aberrations at the surface of the coating in order to achieve 
the desired visual effect such as high distinctness of image (DOI). 
In the field of automotive coatings, it has become an objective to obtain a 
clearcoat (i.e., the outermost automotive coating) that is resistant to 
being etched by environmental fallout. Environmental etching is manifested 
by pitting, water spotting or chemical spotting of the coating or any 
combination of these. Environmental etch resistance is desirable because 
it improves the appearance and useful life of the coating. 
Environmental etch resistance can be measured by visual examination of the 
coating, or by a profilometer or by subjecting a coating on a test panel 
to a saline solution in a temperature gradient oven test. Environmental 
etch resistance is generally measured by visual examination by individuals 
skilled at examining finishes for the degree of environmental etch 
therein. Environmental etch resistance has become more important as the 
amount of acid rain, and other industrial fallout has increased. 
Currently, environmental etching of automotive finishes is generally 
greatest in the areas most greatly affected by industrial fallout. 
The incorporation of the HALS or UVAs as free additions or as polymer or 
oligomer bound UVA or HALS into a coating composition generally improves 
resistance of the coating composition to degradation caused by ultraviolet 
light exposure. Binding the HALS or UVA to an oligomer or polymer 
stabilizes the HALS or UVA in a coating composition, prevents migration of 
the UVA or HALS into other coating layers and retains the UVA or HALS in 
the clearcoat, where it is needed. 
A coating composition containing a carbamate functional resin has shown to 
be effective against environmental etch even without the addition of HALS 
and UVAs. The addition of free HALS and UVAs, (i.e. not polymer- or 
oligomer-bound), has effected little or no improvement in environmental 
etch resistance in the coatings containing carbamate functional resins. 
Unexpectedly, it has been shown that addition of the polymer- or 
oligomer-bound HALS or UVA to a carbamate containing coating provides 
improved environmental etch resistance of the cured film. 
SUMMARY OF THE INVENTION 
According to the present invention, durability enhancing agents comprising 
oligomer-bound and polymer-bound ultraviolet light absorber (UVA) or 
hindered amine light stabilizer (HALS) compounds comprise a UVA and/or 
HALS bonded to an oligomeric or polymeric component, and the agents 
include more than one carbamate functional group, or group convertible to 
a carbamate functional group. The oligomer or polymer may comprise more 
than one UVA or HALS bound thereto, or a mixture of UVA(s) and HALS bound 
thereto. The oligomer-bound or polymer-bound UVA or HALS may also include 
additional reactive functionality that is crosslinkable into a cured 
coating film. 
The oligomer- or polymer-bound HALS or UVA may comprise the principal resin 
or a separate component of the coating composition. The invention is also 
directed to the cured coating composition, and a method for incorporating 
ultraviolet light absorbing compounds and hindered amine light stabilizers 
into a cured coating composition comprising reacting the ultraviolet light 
absorbing and/or hindered amine light stabilizing compound into a 
crosslinked matrix which is formed upon curing the coating composition. 
Generally, the incorporation of the polymer- or oligomer-bound UVA or HALS 
into a coating composition stabilizes the HALS or UVA in a coating 
composition, prevents migration of the UVA or HALS into other coating 
layers and retains the UVA or HALS in the where it is needed. The polymer- 
or oligomer-bound HALS or UVA according to the present invention, 
including carbamate functionality, provides the unexpected result of 
improved environmental etch resistance of the cured film. 
DETAILED DESCRIPTION OF THE INVENTION 
The present invention is a durability enhancing agent which is an acrylic 
oligomer-bound or acrylic polymer-bound ultraviolet light absorber or 
hindered amine light stabilizer, comprising a UVA or HALS, or mixture of 
UVA and HALS, bonded to an acrylic oligomer or polymer, wherein the agent 
includes more than one carbamate functional group, or group convertible to 
a carbamate functional group and may include other reactive functionality 
that is crosslinkable into a coating film. The oligomer- or polymer-bound 
HALS or UVA may comprise the principal resin or a separate component of a 
coating composition. 
The ultraviolet light absorber or hindered amine light stabilizer compounds 
are reacted onto the oligomer or polymer by addition or grafting 
reactions. The UVA or HALS may be copolymerized with monomers used to form 
the oligomer or polymer. 
Examples of ultraviolet light absorbers useful in the present invention 
include benzotriazoles, 2-hydroxybenzophenones, oxanilide, and 
2-hydroxyphenyltriazines. In a preferred embodiment, the ultraviolet 
absorber is a polymer-bound benzotriazole. 
One example of benzotriazole useful in the present invention is shown in 
formula (Ia): 
##STR1## 
wherein, in the compounds of the formula (Ia), R.sub.1, R.sub.2 and 
R.sub.3 can be hydrogen, but at least one of the radicals R.sub.1 and 
R.sub.2 must be other than hydrogen. Additionally, R.sub.1, R.sub.2 and 
R.sub.3 can be halogen, hydroxyl halogen methyl, alkyl having 1 to 18 
carbons, phenyl alkyl having 1 to 4 carbons in the alkyl moiety, hydroxy 
alkyl having 1 to 24 carbon atoms in the alkyl chain, such as methyl, 
ethyl, propyl, butyl, hexyl, octyl, nonyl, dodecyl, tetradecyl, hexadecyl, 
octadecyl, nonadecyl and eicosyl and also corresponding branched isomers, 
alkyl substituted by --COOH, --COOY.sub.8, --CONH.sub.2, --CONHY.sub.9, 
--CONY.sub.9 Y.sub.10, --NH.sub.2, --NHY.sub.9, --NY--.sub.9 Y.sub.10, 
--NHCOY.sub.11, --CN, and/or --OCOY.sub.11, which has 4 to 20 carbon 
atoms, is interrupted by one or more oxygen atoms and is unsubstituted or 
substituted by hydroxyl or alkoxy having 1 to 12 carbon atoms, alkenyl 
having 3 to 6 carbon atoms, glycidyl, cyclohexyl which is unsubstituted or 
substituted by hydroxyl, alkyl having 1 to 4 carbon atoms and/or 
--OCOY.sub.11, phenylalkyl which has 1 to 5 carbon atoms in the alkyl 
moiety and is unsubstituted or substituted by hydroxyl, chlorine and/or 
methyl, --COY.sub.12 or --SO.sub.2 Y.sub.13, or, if u is 2, Y.sub.2 is 
alkylene having 2 to 16 carbon atoms, alkylene having 4 to 12 carbon 
atoms, xylene, alkylene which has 3 to 20 carbon atoms, is interrupted by 
one or more --O-- atoms and/or substituted by hydroxyl, --CH.sub.2 
CH(OH)CH.sub.2 --O--Y.sub.15, --OCH.sub.2 CH(OH)CH.sub.2, --CO--Y.sub.16 
--CO--, --CO--NH--Y.sub.17 --NH--CO--, or --(CH.sub.2).sub.m --CO.sub.2 
--Y.sub.18 --OCO--(CH.sub.2).sub.m, in which m is 1,2 or 3, Y.sub.8 is 
amine, alkylamine or cycloalkylamine wherein the alkyl or cyclosalkyl 
group is between 1 and 6 carbon atoms and may be substituted or 
unsubstituted, alkyl having 1 to 18 carbon atoms, alkenyl having 3 to 18 
carbon atoms, alkyl which has 3 to 20 carbon atoms, is interrupted by one 
or more oxygen or sulfur atoms or --NT.sub.6 -- and/or is substituted by 
hydroxyl, alkyl which has 1 to 4 carbon atoms and is substituted by 
--P(O)(OY.sub.14).sub.2, 
--NY.sub.9 Y.sub.10 or --OCOY.sub.11 and/or hydroxyl, alkenyl having 3 to 
18 carbon atoms, glycidyl, or phenylalkyl having 1 to 5 carbon atoms in 
the alkyl moiety, Y.sub.9 and Y.sub.11 independently of one another are 
alkyl having 1 to 12 carbon atoms, alkoxyalkyl having 3 to 12 carbon 
atoms, dialkylaminoalkyl having 4 to 16 carbon atoms or cyclohexyl having 
5 to 12 carbon atoms, or Y.sub.9 and Y.sub.10 together are alkylene, 
oxalkylene or azaalkylene having in each case 3 to 9 carbon atoms, 
Y.sub.11 is alkyl having 1 to 18 carbon atoms, alkenyl having 2 to 18 
carbon atoms or phenyl, Y.sub.12 is alkyl having 1 to 18 carbon atoms, 
alkenyl having 2 to 18 carbon atoms, phenyl, alkoxy having 1 to 12 carbon 
atoms, phenoxy, alkylamino having 1 to 12 carbon atoms or phenylamino, 
Y.sub.13 is alkyl having 1 to 18 carbon atoms, phenyl or alkyphenyl having 
1 to 8 carbon atoms in the alkyl radical, Y.sub.14 is alkyl having 1 to 12 
carbon atoms or phenyl, Y.sub.15 is alkylene having 2 to 10 carbon atoms, 
pheneylene or a group -phenylene-M-phenylene- in which M is --O--, --S--, 
--SO.sub.2 --, --CH.sub.2 -- or --C(CH.sub.3).sub.2 --, Y.sub.16 is 
alkylene, oxyalkylene or thiaalkylene having in each case 2 to 10 carbon 
atoms, phenylene or alkenylene having 2 to 6 carbon atoms, Y.sub.17 is 
alkylene having 2 to 10 carbon atoms, phenylene or alkylphenlene having 1 
to 11 carbon atoms in the alkyl moiety, and Y.sub.18 is alkylene having 2 
to 10 carbon atoms or alkylene which has 4 to 20 carbon atoms and is 
interrupted once or several times by oxygen. 
R.sub.1 may be phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety, 
for example benzyl, and can also be cycloalkyl having 5 to 8 carbon atoms, 
for example cyclopentyl, cyclohexyl and cyclooctyl, or a radical of the 
formula 
##STR2## 
in which R.sub.4 and R.sub.5 independently of one another are alkyl having 
in each case 1 to 5 carbon atoms, in particular methyl, or R.sub.4 
together with the radical C.sub.n H.sub.2n+1-m, forms a cyclolakyl radical 
having 5 to 12 carbon atoms, for example cyclohexyl, cyclooctyl and 
cyclodecyl. M is a radical of the formula --COOR.sub.6 in which R.sub.6 is 
hydrogen, or alkyl having 1 to 12 carbon atoms, or alkoxyalkyl having 1 to 
20 carbon atoms in each of the alkyl and the alkoxy moieties. Suitable 
alkyl radicals R.sub.6 are those enumerated for R.sub.1. Examples of 
suitable alkoxyalkyl groups are --C.sub.2 H.sub.4 OC.sub.2 H.sub.5, 
--C.sub.2 H.sub.4 OC.sub.8 H.sub.17 and --C.sub.4 H.sub.8 OC.sub.4 
H.sub.9. As phenylalkyl having 1 to 4 carbon atoms, R.sub.6 is, for 
example, benzyl, cumyl, .alpha.-methylbenzyl or phenylbutyl. 
At least one of the radicals R.sub.1 and R.sub.2 must be other than 
hydrogen. 
Alternatively, the benzotriazole has the following formula: 
##STR3## 
In the compounds of the formula (Ib) T is hydrogen or alkyl having 1 to 6 
carbon atoms, such as methyl and butyl, T.sub.1 is hydrogen, chlorine or 
alkyl or alkoxy having in each case 1 to 4 carbon atoms, for example 
methyl, methoxy and butoxy, and n is 1 or 2. If n is 1, T.sub.2 is 
chlorine or a radical of the formula --OT.sub.3 or 
##STR4## 
and if n is 2, T.sub.2 is a radical of the formula 
##STR5## 
or --O--T.sub.9 --O--, where T.sub.3 is hydrogen, alkyl which has 1 to 18 
carbon atoms and is unsubstituted or substituted by 1 to 3 hydroxyl groups 
or by --OCOT.sub.6, alkyl which has 3 to 18 carbon atoms, is interrupted 
once or several times by --O-- or --NT.sub.6 -- and is unsubstituted or 
substituted by hydroxyl or --OCOT.sub.6. Examples of T.sub.3 as cycloalkyl 
include cycloalkyl having 5 to 12 carbon atoms, such as cyclopentyl, 
cyclohexyl or cyclooctyl and is unsubstituted or substituted by hydroxyl 
and/or alkyl having 1 to 4 carbon atoms in the alkyl moiety, for example 
benzyl or phenylbutyl. T.sub.3 can also be alkenyl having 2 to 18 carbon 
atoms. Suitable alkenyl radicals are derived from the alkyl radicals 
enumerated in the definitions of R.sub.1. These alkenyl radicals can be 
substituted by hydroxyl. Examples of T.sub.3 as phenylalkyl are benzyl, 
phenylethyl, cumyl, .alpha.-methylbenzyl or benzyl. T.sub.3 can also be a 
radical of the formula --CH.sub.2 C--H(OH)--T.sub.7 or 
##STR6## 
T.sub.4 and T.sub.5 independently of one another are hydrogen, alkyl 
having 1 to 18 carbon atoms, alkyl which has 3 to 18 carbon atoms and is 
interrupted once or several times by --O-- or NT.sub.6 --, cycloalkyl 
having 5 to 12 carbon atoms, for example. phenyl, phenyl which is 
substituted by alkyl having 1 to 4 carbon atoms, alkenyl having 3 to 8 
carbon atoms, phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety 
or hydroxyalkyl having 2 to 4 carbon atoms, T.sub.6 is hydrogen, alkyl 
having 1 to 18 carbon atoms, cycloalkyl having 5 to 12 carbon atoms, 
alkenyl having 3 to 8 carbon atoms, phenyl, phenyl which is substituted by 
alkyl having 1 to 4 carbon atoms, phenylalkyl having 1 to 4 carbon atoms 
in the alkyl moiety, T.sub.7 is hydrogen, alkyl having 1 to 18 carbon 
atoms, phenyl which is unsubstituted or substituted by hydroxyl, 
phenylakyl having 1 to 4 carbon atoms in the alkyl moiety, or --CH.sub.2 
OT.sub.8, T.sub.8 is alkyl having 1 to 18 carbon atoms, alkenyl having 3 
to 8 carbon atoms, cycloalkyl having 5 to 10 carbon atoms, phenyl, phenyl 
which is substituted by alkyl having 1 to 4 carbon atoms, or phenylalkyl 
having 1 to 4 carbon atoms in the alkyl. 
Alternatively, the polymer-bound ultraviolet light absorber may comprise 
triazines such as 2-hydroxyphenyl triazines having the formula (IIa) 
##STR7## 
in the formula (IIa) u is 1 to 2, 
r is an integer from 1 to 3, 
the substituents Y.sub.1 independently of one another are hydrogen, 
hydroxyl, halogen, halogenomethyl, alkyl having 1 to 12 carbon atoms, 
alkoxy having 1 to 18 carbon atoms, when U is 1, Y.sub.2 is alkyl having 1 
to 18 carbon atoms, alkyl which has 1 to 12 carbon atoms and is 
substituted by --COOH, 
--COOY.sub.8, --CONH.sub.2, CONHY.sub.9, --ONY.sub.9 Y.sub.10, --CN, 
--OCOY.sub.11, or mixtures thereof; alkyl which has 4 to 20 carbon atoms 
which is interrupted by one or more oxygen atoms and is unsubstituted or 
substituted by hydroxyl or alkoxy having 1 to 12 carbon atoms; alkenyl 
having 3 to 6 carbon atoms, glycidyl, phenylalkyl which has 1 to 5 carbon 
atoms in the alkyl moiety and is unsubstituted or substituted by hydroxyl, 
chlorine and or methyl; --COY.sub.12 or SO.sub.2 Y.sub.13, wherein Y.sub.8 
is amino, alkylamine or cycloalkylamine, wherein the alkyl or cyloalkyl 
group has up to 6 carbon atoms, alkyl having 1 to 18 carbon atoms, alkenyl 
having 3 to 18 carbon atoms, alkyl which has 3 to 20 carbon atoms, and is 
interrupted by one or more oxygen atoms, or said alkyl substituted by 
substituted by hydroxyl; alkenyl having 3 to 18 carbon atoms, glycidyl or 
phenylalkyl having 1 to 5 carbon atoms in the alkyl moiety, 
Y.sub.9 and Y.sub.10 independently of one another are alkyl having 1 to 12 
carbon atoms, alkoxyalkyl having 3 to 12 carbon atoms, dialkylaminoalkyl 
having 4 to 16 carbon atoms or cyclohexyl having 5 to 12 carbon atoms, 
Y.sub.11 is alkyl having 1 to 18 carbon atoms, alkenyl having 2 to 18 
carbon atoms or phenyl, 
Y.sub.12 is alkyl having 1 to 18 carbon atoms, alkenyl having 2 to 18 
carbon atoms, phenyl, alkoxy having 1 to 12 carbon atoms, phenoxy, 
alkylamino having 1 to 12 carbon atoms or phenylamino, 
Y.sub.13 is alkyl having 1 to 18 carbon atoms, phenyl or alkylphenyl having 
1 to 8 carbon atoms in the alkyl radical; and when u is 2, Y.sub.2 is 
alkylene having 2 to 16 carbon atoms, alkylene having 4 to 12 carbon atoms 
and is interrupted by one or more --O-- atoms and/or is substituted by 
hydroxyl; --CH.sub.2 CH(OH)CH.sub.2 --O--Y.sub.15 --OCH.sub.2 
CH(OH)CH.sub.2, or 
--(CH.sub.2).sub.m --CO.sub.2 --Y.sub.18 --OCO--(CH.sub.2).sub.m, in which 
m is 1,2 or 3, 
Y.sub.15 is alkylene having 2 to 10 carbon atoms, phenylene or a group 
-phenylene-M-phenylene- in which M is --O--, --S--, --SO.sub.2 --, 
--CH.sub.2 -- or --C(CH.sub.3).sub.2 --, 
and Y.sub.18 is alkylene having 2 to 10 carbon atoms or alkylene which has 
4 to 20 carbon atoms and is interrupted once or several times by oxygen. 
Examples of hindered amine light stabilizers useful in the present 
invention include derivatives of 2,2,6,6-tetramethylpiperidine. These 
stabilizers protect polymers by functioning as light-stable antioxidants. 
The hindered amine light stabilizers contain a reactive functionality 
thereon for reaction with the polymer or oligomer. The reactive 
functionality may comprise a group such as hydroxyl, carboxyl, amine, or 
ethylenically unsaturated group. The ultraviolet light absorber or 
hindered amine light stabilizer compounds are reacted onto the oligomer or 
polymer by addition or grafting reactions with the reactive functionality 
on the HALS or UVA. Example of such HALS are set forth in U.S. Pat. Nos. 
5,216,156 to Galbo, 5,004,770 and 5,124,378 to Behrens et al. 
One such example of a suitable HALS for purposes of the present invention 
is an O-substituted N-hydroxyl hindered amine light stabilizer having the 
formula: 
##STR8## 
wherein R is hydrogen or methyl, R.sub.1 is independently C.sub.1 
-C.sub.18 alkyl, C.sub.2 -C.sub.18 alkenyl, C.sub.2 -C.sub.18 alkynyl, 
C.sub.5 -C.sub.12 cycloalkyl, C.sub.6 -C.sub.10 bicycloalkyl, C.sub.5 
-C.sub.8 cycloalkenyl, C.sub.6 -C.sub.10 aryl, C.sub.7 -C.sub.9 aralkyl, 
C.sub.7 -C.sub.9 aralkyl substituted by alkyl or aryl, or 
##STR9## 
wherein D is C.sub.1 -C.sub.18 alkyl, C.sub.1 -C.sub.18 alkoxy, phenyl, 
phenyl substituted by hydroxy, alkyl or alkoxy, or amino or amino mono- or 
di-substituted by alkyl or phenyl; 
m is 1-4, 
when m is 1, 
R.sub.2 is hydrogen, C.sub.1 -C.sub.18 alkyl optionally interrupted by one 
or more oxygen atoms, C.sub.2 -C.sub.12 alkenyl, C.sub.6 -C.sub.10 aryl, 
C.sub.7 -C.sub.18 aralkyl, glycidyl, a monovalent acyl radical of an 
aliphatic cycloaliphatic, araliphatic or aromatic carboxylic acid, or of a 
carbamic acid 
##STR10## 
wherein x is 0 or 1, or 
##STR11## 
wherein y is 2-4; when m is 2, 
R.sub.2 is C.sub.1 -C.sub.12 alkylene, C.sub.4 -C.sub.12 alkenylene, 
xylylene, a divalent acyl radical of an aliphatic, cycloaliphatic, 
araliphatic or aromatic dicarboxylic acid or of a dicarbamic acid, 
when m is 3, R.sub.2 is a trivalent acyl radical of an aliphatic, 
unsaturated aliphatic, cycloaliphatic, or aromatic tricarboxylic acid; 
when m is 4, R.sub.2 is a tetravalent acyl radical of a saturated or 
unsaturated aliphatic or aromatic tetracarboxylic acid; 
p is 1, 2 or 3. 
Another example of a suitable HALS for purposes of the present invention 
has the formula: 
##STR12## 
wherein E.sub.1, E.sub.2, E.sub.3 and E.sub.4 are independently alkyl of 1 
to 4 carbon atoms, or E.sub.1 and E.sub.2 are independently alkyl of 1 to 
4 carbon atoms and E.sub.3 and E.sub.4 taken together are pentamethylene, 
or E.sub.1 and E.sub.2 ; and E.sub.3 and E.sub.4 each taken together are 
pentamethylene, R.sub.1 is alkyl of 1 to 18 carbon atoms, cycloalkyl of 5 
to 12 carbon atoms, a bicyclic or tricyclic hydrocarbon radical of 7 to 12 
carbon atoms, phenylalkyl of 7 to 12 carbon atoms, phenylalkyl of 7 to 15 
carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one 
to three alkyl of 1 to 8 carbon atoms, 
R.sub.2 is hydrogen or a linear or branched chain alkyl of 1 to 12 carbon 
atoms, 
R.sub.3 is alkylene of 1 to 8 carbon atoms, or R.sub.3 is 
--CO--,--CO--R.sub.4 --, --CONR.sub.2 --, or --CO--NR-R.sub.4, 
R.sub.4 is alkylene of 1 to 8 carbon atoms, 
T is phenoxy, phenoxy substituted by one or two alkyl groups of 1 to 4 
carbon atoms, alkoxy of 1 to 8 carbon atoms or --N(R.sub.2).sub.2 with the 
stipulation that R.sub.2 is not hydrogen, or T is 
##STR13## 
X is --NH.sub.2, --NCO, --OH, --O-glycidyl, or --NHNH.sub.2, and Y is 
--OH, --NH.sub.2, --NHR.sub.2 where R.sub.2 is not hydrogen; or Y is 
--NCO, --COOH, oxiranyl, --O-glycidyl, or --Si(OR.sub.2).sub.3 ; or the 
combination R.sub.3 --Y-- is --CH.sub.2 OR.sub.2. 
In a preferred embodiment E.sub.1 to E.sub.4 are each methyl; 
R.sub.1 is cyclohexyl, octyl, methyl, or heptyl; 
R.sub.2 is hydrogen, butyl, or dodecyl; 
R.sub.3 is ethylene when Y is --OH or R.sub.3 is pentamethylene when Y is 
--COOH; 
R.sub.4 is ethylene or hexamethylene; and 
A is --N(R.sub.7)-- wherein R.sub.7 is butyl. 
The oligomeric and polymeic components according to the invention can be 
prepared in a variety of ways. The oligomer has a molecular weight of 
between 148 and 2000, the preferred molecular weight for the oligomers is 
between 900 and 1092; polymers have a molecular weight of between 2,000 
and 20,000, the preferred molecular weight for the polymers is between 
4000 and 6000. Mixtures of said oligomers and polymers may be used. 
Molecular weight can be determined by the GPC method using a polystyrene 
standard. These weights are prior to reaction of the components with the 
UVA or HALS. The oligomeric or polymeric component may include the 
carbamate functionality or the carbamate functionality may be reacted on 
to the UVA or HALS component. The carbamate content of the polymer, on a 
molecular weight per equivalent of carbamate functionality, will generally 
be between 200 and 1200, and preferably between 300 and 800. 
One method of preparation of oligomeric compounds having carbamate 
functionality is to react an alcohol (`alcohol` is defined herein as 
having one or more OH groups) with more than one urea to form a compound 
with carbamate groups. This reaction is accomplished by heating a mixture 
of the alcohol and ureas. This reaction is also performed under heat, 
preferably in the presence of a catalyst as is known in the art. Another 
technique is the reaction of an alcohol with cyanic acid to form a 
compound with primary carbamate groups (i.e., unsubstituted carbamates). 
Carbamates may also be prepared by reaction of an alcohol with phosgene 
and then ammonia to form a compound having primary carbamate groups, or by 
reaction of an alcohol with phosgene and then a primary amine to form a 
compound having secondary carbamate groups. Another approach is to react 
an isocyanate (e.g., HDI, IPDI) with a compound such as hydroxypropyl 
carbamate to form a carbamate-capped isocyanate derivative. Finally, 
carbamates can be prepared by a transcarbamylation approach where an 
alcohol is reacted with an alkyl carbamate (e.g., methyl carbamate, ethyl 
carbamate, butyl carbamate) to form a primary carbamate group-containing 
compound. This reaction is performed under heat, preferably in the 
presence of a catalyst such as an organometallic catalyst (e.g., 
dibutyltin dilaurate). Other techniques for preparing carbamates are also 
known in the art and are described, for example, in P. Adams & F. Baron, 
"Esters of Carbamic Acid", Chemical Review, v. 65, 1965. 
Various alcohols can be used in the preparation of carbamate compounds 
useful in the invention. They generally have from 1 to 200 carbon atoms, 
preferably 1-60 carbon atoms, and may be monofunctional or polyfunctional 
(preferably a functionality of 2 to 3), aliphatic, aromatic, or 
cycloaliphatic. They may contain just OH groups, or they may contain OH 
groups plus heteroatoms such as O, S, Si, N, P, and other groups such as 
ester groups, ether groups, amino groups, or unsaturated sites. Examples 
of useful alcohols include 1,6-hexanediol,1,2-hexanediol, 
2-ethyl-1,3-hexanediol, ethyl-propyl-1,5-pentanediol, 
2-methyl-2,4-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 
2,4,7,9-tetramethyl-5-decyn-4,7-diol, 1,3-dihydroxyacetone dimer, 
2-butene-1,4-diol, pantothenol, dimethyltartrate, pentaethylene glycol, 
dimethyl silyl dipropanol, and 2,2'-thiodiethanol. 
Where, the polymeric component is a carbamate functional acrylic polymer, 
the polymer is represented by the randomly repeating units according to 
the following formula: 
##STR14## 
In the above formula, R represents H or CH.sub.3. R' represents H, alkyl, 
preferably of 1 to 6 carbon atoms, or cycloalkyl, preferably up to 6 ring 
carbon atoms. It is to be understood that the terms alkyl and cycloalkyl 
are to include substituted alkyl and cycloalkyl, such as 
halogen-substituted alkyl or cycloalkyl. Substituents that will have an 
adverse impact on the properties of the cured material, however, are to be 
avoided. For example, ether linkages are thought to be susceptible to 
photo-induced hydrolysis, and should be avoided in locations that would 
place the ether linkage in the crosslink matrix. The values x and y 
represent weight percentages, with x being 10 to 90 % and preferably 20 to 
50%, and y being 90 to 10% and preferably 80 to 50%. 
In the formula, A represents repeat units derived from one or more 
ethylenically unsaturated monomers. Such monomers for copolymerization 
with acrylic monomers are known in the art. They include alkyl esters of 
acrylic or methacrylic acid, e.g., ethyl acrylate, butyl acrylate, 
2-ethylhexyl acrylate, butyl methacrylate, isodecyl methacrylate, 
hydroxyethyl methacrylate, hydroxypropyl acrylate, and the like; and vinyl 
monomers such as unsaturated m-tetramethyl xylene isocyanate (sold by 
American Cyanamid as TMI.RTM.), vinyl toluene, styrene, styrenic 
derivatives such as .alpha.-methyl styrene, t-butyl styrene, and the like. 
L represents a divalent linking group, preferably an aliphatic group of 1 
to 8 carbon atoms, cycloaliphatic, or aromatic linking group of 6 to 10 
carbon atoms. Examples of L include 
##STR15## 
--(CH.sub.2)--, --(CH.sub.2).sub.2 --, --(CH.sub.2).sub.4 --, and the 
like. In one preferred embodiment, --L-- is represented by --COO--L'-- 
where L' is a divalent linking group. Thus, in a preferred embodiment of 
the invention, the polymer component (a) is represented by randomly 
repeating units according to the following formula: 
##STR16## 
In this formula, R, R', A, x, and y are as defined above. L' may be a 
divalent aliphatic linking group, preferably of 1 to 8 carbon atoms, e.g., 
--(CH.sub.2)--, --(CH.sub.2).sub.2 --, --(CH.sub.2).sub.4 --, and the 
like, or a divalent cycloaliphatic linking group, preferably up to 8 
carbon atoms, e.g., cyclohexyl, and the like. However, other divalent 
linking groups can be used, depending on the technique used to prepare the 
polymer. For example, if a hydroxyalkyl carbamate is adducted onto an 
isocyanate-functional acrylic polymer, the linking group L' would include 
an --NHCOO-- urethane linkage as a residue of the isocyanate group. This 
carbamate functional acrylic polymer is described in U.S. Pat. No. 
5,474,811 which is hereby incorporated by reference. The carbamate 
functional polymer component used in the composition of the invention can 
be prepared in a variety of ways. One way to prepare such polymers is to 
prepare an acrylic monomer having a carbamate functionality in the ester 
portion of the monomer. Such monomers are well-known in the art and are 
described, for example in U.S. Pat. Nos. 3,479,328, 3,674,838, 4,126,747, 
4,279,833, and 4,340,497, the disclosures of which are incorporated herein 
by reference. One method of synthesis involves reaction of a hydroxy ester 
with urea to form the carbamyloxy carboxylate (i.e., carbamate-modified 
acrylic). Another method of synthesis reacts an .alpha.,.beta.-unsaturated 
acid ester with a hydroxy carbamate ester to form the carbamyloxy 
carboxylate. Yet another technique involves formation of a hydroxyalkyl 
carbamate by reacting ammonia, or a primary or secondary amine or diamine 
with a cyclic carbonate such as ethylene carbonate. The hydroxyl group on 
the hydroxyalkyl carbamate is then esterified by reaction with acrylic or 
methacrylic acid to form the monomer. Other methods of preparing 
carbamate-modified acrylic monomers are described in the art, and can be 
utilized as well. The acrylic monomer can then be polymerized along with 
other ethylenically-unsaturated monomers, if desired, by techniques 
well-known in the art. 
An alternative route for preparing a carbamate functional acrylic polymer 
for use in the composition of the invention is to react an already-formed 
polymer such as an acrylic polymer with another component to form a 
carbamate-functional group appended to the polymer backbone, as described 
in U.S. Pat. No. 4,758,632, the disclosure of which is incorporated herein 
by reference. One technique for preparing such acrylic polymers involves 
thermally decomposing urea (to give off ammonia and HNCO) in the presence 
of a hydroxy-functional acrylic polymer or copolymer to form a 
carbamate-functional acrylic polymer. Another technique involves reacting 
the hydroxyl group of a hydroxyalkyl carbamate with the isocyanate group 
of an isocyanate-functional acrylic or vinyl monomer to form the 
carbamate-functional acrylic. Isocyanate-functional acrylics are known in 
the art and are described, for example in U.S. Pat. No. 4,301,257, the 
disclosure of which is incorporated herein by reference. Isocyanate vinyl 
monomers are well-known in the art and include unsaturated m-tetramethyl 
xylene isocyanate (sold by American Cyanamid as TMI.RTM.). Yet another 
technique is to react the cyclic carbonate group on a cyclic 
carbonate-functional acrylic with ammonia in order to form the 
carbamate-functional acrylic. Cyclic carbonate-functional acrylic polymers 
are known in the art and are described, for example, in U.S. Pat. No. 
2,979,514, the disclosure of which is incorporated herein by reference. A 
more difficult, but feasible way of preparing the polymer would be to 
trans-esterify an acrylate polymer with a hydroxyalkyl carbamate. 
A cured coating composition according to the present invention includes a 
durability enhancing agents comprising a monomeric, oligomeric, or 
polymeric component having bonded thereto at least one HALS and/or UVA, 
said durability enhancing agent having appended thereto more than one 
carbamate functional group, or group convertible to a carbamate functional 
group. The durability enhancing agent may also include other reactive 
functionality that may be crosslinked into the film. Examples of such 
functionality includes acid, epoxy, hydroxy, ester and ether 
functionality. The HALS or UVA may be reacted via a grafting reaction or 
copolymerized in an addition reaction. 
In a preferred embodiment, the durability enhancing agent comprises the 
reaction product of an acrylic polymer or acrylic oligomer that is 
carbamate functional or has functionality convertible to carbamate 
functionality, UVA or HALS including that can act as grafting sites for 
UVA or HALS compounds. An example of this is reaction of 2-carbamate ethyl 
methacrylate with either a (Norblock) and/or TMI, followed by reaction 
with a hydroxyl functional UVA or HALS. Other monomers may be also 
included in the reaction. Other carbamates such as those listed in U.S. 
Pat. Nos. 5,356,669 and 5,474,811 may also be used. 
The durability enhancing agent may comprise the principal resin of the 
coating composition, or may be added as a separate component to a coating 
composition. 
A coating composition according to the present invention is cured by self 
crosslinking, or by reaction of the principal resin with a crosslinking 
agent having a plurality of functional groups that are reactive with the 
crosslinkable groups on the principal resin. Such reactive groups include 
active methylol or methylalkoxy groups on aminoplast crosslinking agents 
or on other compounds such as phenol/formaldehyde adducts, isocyanate 
groups, siloxane groups, cyclic carbonate groups, and anhydride groups. 
Examples of crosslinking agents include melamine formaldehyde resin 
(including monomeric or polymeric melamine resin and partially or fully 
alkylated melamine resin), blocked or unblocked polyisocyanates (e.g., 
TDI, MDI, isophorone diisocyanate, hexamethylene diisocyanate, and 
isocyanurate trimers of these, which may be blocked for example with 
alcohols or oximes), Aminoplast resin such as melamine formaldehyde resin 
or urea formaldehyde resin are especially preferred. 
The preferred aminoplast resins for this purpose include monomeric or 
polymeric melamine formaldehyde resins, alkoxylated melamine formaldehyde 
resins and mixtures of alkoxylated melamine formaldehyde resins. The 
isocyanate crosslinkers suitable for purposes of the present invention 
include TDI, MDI, isophorone diisocyanate, hexamethylene diisocyanate, and 
isocyanurate trimers of these, which may be blocked for example with 
alcohols or oximes selected from the group consisting of triazines 
benzotriazoles, 2-hydroxybenzophenone compounds, oxanilides, and mixtures 
thereof. 
Where an aminoplast crosslinking agent is used, and the aminoplast is 
reacted with carbamate functionality, or functionality convertible to a 
carbamate, excess aminoplast groups are left to crosslink with the 
reactive functionality on the principal resin. 
While the oligomer-bound or polymer-bound HALS may be used in any layer of 
a multi-layer coating composition, it is preferably used in a clearcoat 
composition. The clearcoat may be used alone or with a pigmented basecoat 
composition. 
The pigmented basecoat composition may any of a number of types well-known 
in the art, and does not require explanation in detail herein. Polymers 
known in the art to be useful in basecoat compositions include acrylics, 
vinyls, polyurethanes, polycarbonates, polyesters, alkyds, and 
polysiloxanes. Preferred polymers include acrylics and polyurethanes. In 
one preferred embodiment of the invention, the basecoat composition also 
utilizes a carbamate-functional acrylic polymer. Basecoat polymers may be 
thermoplastic, but are preferably crosslinkable and comprise one or more 
type of cross-linkable functional groups. Such groups include, for 
example, hydroxy, isocyanate, amine, epoxy, acrylate, vinyl, silane, and 
acetoacetate groups. These groups may be masked or blocked in such a way 
so that they are unblocked and available for the cross-linking reaction 
under the desired curing conditions, generally elevated temperatures. 
Useful cross-linkable functional groups include hydroxy, epoxy, acid, 
anhydride, silane, and acetoacetate groups. Preferred cross-linkable 
functional groups include hydroxy functional groups and amino functional 
groups. 
Basecoat polymers may be self-cross-linkable, or may require a separate 
cross-linking agent that is reactive with the functional groups of the 
polymer. When the polymer comprises hydroxy functional groups, for 
example, the cross-linking agent may be an aminoplast resin, isocyanate 
and blocked isocyanates (including isocyanurates), and acid or anhydride 
functional cross-linking agents. 
The coating compositions described herein are preferably subjected to 
conditions so as to cure the coating layers. Although various methods of 
curing may be used, heat-curing is preferred. Generally, heat curing is 
effected by exposing the coated article to elevated temperatures provided 
primarily by radiative heat sources. Curing temperatures will vary 
depending on the particular blocking groups used in the cross-linking 
agents, however they generally range between 93.degree. C. and 177.degree. 
C.

The invention is further illustrated by the following non-limiting 
examples. 
EXAMPLES 
Example 1 
Acrylic Polymer-Bound Benzotriazole 
Polymer-bound Ultraviolet Light Absorber 
A polymer-bound ultraviolet light absorber containing 2.0% benzotriazole, 
based on total coating solids, was prepared by polymerizing 28.4 grams of 
a benzotiazole, sold under the trademark Norbloc.TM. 7966, available from 
Noramco, Inc. onto 1514.3 grams of a hydroxy functional carbamate resin, 
sold under the trademark Ureclear.RTM., commercially available from BASF 
Corporation. The hydroxy functional carbamate resin had a hydroxy 
equivalency of 1650 g/equivalent at 95% non-volatile content. 
Example 2 
Coating Composition (Control) 
A control coating composition was prepared having the following 
formulation: 
______________________________________ 
Ingredient Amount 
______________________________________ 
Carbamate functional acrylic resin.sup.1 
75.51 
Resimine 747 Aminoplast 20.66 
Acid Catalyst 1.00 
Fumed Silica Rheology Control Additive 1.31 
Flow Control Additive 0.20 
Adhesion promoter 1.32 
Total 100.00 
______________________________________ 
.sup.1 Carbamate functional acrylic available from BASF Corp. under the 
trademark Ureclear .RTM., as described in U.S. Pat. No. 5,356,669. 
Example 3 
Coating Composition Containing Various Additions of UVAs and HALS 
To the coating composition in Example 2 were added the following HALS and 
UVAs. Amounts are in percent by weight based on total coating composition 
solids content. The additions of the HALS and UVAs are set forth below. 
______________________________________ 
Ingredient Ex. A* Ex. B Ex. C 
______________________________________ 
Polymeric benzotriazole from Ex. 1 
-- 2% 1.5% 
2-hydroxyphenyl triazine free add** -- -- 2.0% 
3058 1.0 -- 1.0 
1164 1.5 -- 1.5% 
______________________________________ 
*Ex. A is the control coating composition. 
**Free add means that the triazine is not polymer or oligomer bound. 
TABLE 1 
______________________________________ 
Comparative Data for Environmental etch Results of Coating 
Compositions 
Example Environmental etch Rating 
______________________________________ 
Ex. A 5-6 
Ex. B 3-4 
Ex. C 4-5 
______________________________________