Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
- l -
GLYCIDYL-H`(DROXY-ACRYLIC HIGH SOLIDS
COATING COMPOSITIONS
This invention relates to high solids,
thermosetting coating compositions, which when cured,
5 exhibit excellent weather ability and are adapted to
provide an automotive topcoat which demonstrates hardness,
high gloss and excellent resistance to solvents and water.
More particularly, the coating compositions of this
invention comprise a mixture of a low molecular weight
glycidyl-functional/hydroxyl-functional acrylic copolymer,
dicarboxylic avid android including at least about 50
weight percent of alkyd hexahydrophthatic android,
amine-aldehyde cross linking resins and solvent. The
composition mixture reacts in situ during curing at
elevated temperature to form the coating.
because of increasingly strict solvent emission
regulations in recent years, low solvent emission paints
have become very desirable. A number of high solids paint
compositions have been proposed to meet these low solvent
emission requirements However, many of the compositions
are deficient because of difficulty in application, slow
curing rates, complex and/or time consuming composition
formulation, poor durability and low solvent and water
resistance of the coating.
One composition, which has been proposed to
overcome these deficiencies is taught in U.S. Patent No.
4,394,486. In that composition, hydroxy functional acryl-
to copolymers react with androids of dicarboxylic acids
to produce hydroxy acid and pulsed copolymers. The
composition of such a mixture is largely dictated by -the
stoichiometry of the reactants employed. These acid
products are then reacted with epoxies to produce hydroxy
functional resins. Subsequently a composition comprising
a mixture of these hydroxy functional resins and amine-
alluded cross linking agent can be applied to a substrate
and cured at elevated temperatures to obtain a cross linked
structure. Unexpectedly, we have now Found that all of
the aforementioned reactions can be carried out in situ
,- I
- 2 Lowe
during curing on the substrate to obtain high solids
coatings with excellent physical properties. While not
wishing to be bound by theory, it is believed that in this
reaction sequence the hydroxyl functionality of the guy-
swaddle hydroxy acrylic copolymer reacts with the anhydrideto produce acid functionality which further reacts with
the epoxide functionality of the copolymer to produce
hydroxyl moiety; then at higher temperatures, the amine-
alluded reacts with the hydroxyl functionality to produce
a cross linked network. This cross linking reaction is
facilitated by the unconsumed acid present in the compost-
lion.
The thermosetting coating composition of this invent
lion, which reacts in situ during curing at elevated
temperatures, preferably contains greater than about 60
by
weight, more preferably greater than 70% by weight, of
nonvolatile solids. The composition is characterized in
that it comprises a mixture of
(A) acrylic copolymer bearing pendant epoxide
groups and pendant hydroxyl groups, wherein the total of
such epoxide and hydroxyl groups per molecule is
preferably greater than about three, most preferably about
five, and having a number average molecular weight no of
between about LUKE and about S000, preferably between
about lS00 and about 3000;
(B) dicarboxylic acid android comprising at
least about 50 weight percent, preferably greater than
about 80 weight percent, of alkyd hexahydrophthalic
android;
(C) amine-aldehyde cross linking agent; and
(D) solvent.
The composition reacts in situ during curing at elevated
temperatures to form the coating.
The acrylic copolymer is prepared from a monomer
mixture comprising (i) between about 5 and about 35,
preferable between about 10 and about 20 weight percent of
glycidyl ester of a monoethylenically unsaturated
carboxylic acid, (ii) between about 5 and about 35,
preferably between about 10 and about 20 weight percent of
US hydroxy alkyd acrylate or hydroxy alkyd methacrylate and
(iii) between about 60 and about 90 weight percent of
other monoethylenically unsaturated monomers. The
dicarboxylic acid android is included in an amount so as
to provide between about 1.0 and about 1.2, preferably
about 1.0 android groups per epoxide group on the
acrylic copolymer. The amine-aldehyde is included in the
- 4 3~3~
composition in amount sufficient to provide at least about
0.60, preferably between about 0.75 and 2.75 nitrogen
crosslinkinq functional group for each hydroxyl group
initially present in the composition on the acrylic
copolymer (A).
In addition, the coating composition of this
invention may include additives such as catalysts,
antioxidant, US absorbers, flow control or wetting
agents, antistatic agents, pigmel-lts, plasticizers, etch
The compositions of this invention are also compatible with
Nancy dispersions (Nudes), which are generally- used
as flow control additives
This invention overcomes the above mentioned
deficiencies of prior high solids coating compositions arid
provides a high solids composition particularly suitable
for use as an automotive topcoat clear or pigmented, which
exhibits outstanding weather ability.
Advantageously, since the composition of this
invention is applied to the substrate as an essentially
unrequited mixture of low molecular weight materials, little
solvent is required to maintain a desirable low
application viscosity, i.e., the composition can be of
very high solids level
The composition of this invention, being of
essentially single step formulation, offers a distinct
commercial advantage over those compositions whose
formulation includes a series of reaction steps prior to
curing, since such reaction steps generally require heat,
agitation and monitoring for extended periods of time.
Advantageously, during the in situ reactions
during curing of the composition of this invention,
carboxyl functionality is generated which, until it is
later consumed by further reaction, acts as a catalyst for
the cross linking reaction.
- 5 -
The coating compositions of this invention
provide a system which is particularly suitable for those
applications requiring a coating having high gloss,
hardness, adhesion, high solvent and water resistance and
superior weather ability. The components of the coating
composition of this invention are combined to form a
homogeneous mixture which is then applied to a substrate
and cured at elevated temperatures.
Mach of the components of the coating
composition the amounts of each of the components
required to achieve the desired results of the invention
and a method for applying the composition are described
hereinafter in greater detail.
(A) Glycidyl-Hydroxy Functional Acrylic Polymer
One material in the high solids coating
composition of this invention is glycidyl-hydroxy acrylic
copolymer, i.e. r copolymer bearing pendant epoxide and
hydroxyl groups, which may be prepared by conventional
free radical induced polymerization of suitable alpha-beta
unsaturated monomers. The term "copolymer" as used herein
refer to a copolymer of two or more different monomers at
least one of which contains pendant epoxide groups and at
least one of which contains pendant hydroxyl groups.
The copolymers used in the coating composition of
this invention have a number average molecular weight (My)
of between about 1000 and about 5000, preferably between
about 1500 and about 3000.
The monomers used to prepare the copolymer also
include between about 5 and about 35 weight percent of one
or more glycidyl esters of a monoethylenically unsaturated
~3~;~3i~
6 --
carboxylic acid, e.g., glycidyl acrylate and glycidyl
methacrylate. These monomers provide the copolymer with
its epoxide functionality.
The monomers used to prepare the copolymer
include between about 5 and about 35 weight percent of one
or more monoethylenically unsaturated monomers bearing
hydroxyl functionality. The monoethylenically unsaturated
hydroxy functional monomers useful in preparation of the
copolymer and providing the hydroxy functionality to the
lo copol~mer may be selected from a long list of hydroxy
functional monomers. Preferably, however, the hydroxy
functional monomers are acrylates and may be selected from
the group consisting of, but not limited to the following
esters of acrylic or methacrylic acids and aliphatic
lo alcohols: 2-hydroxyethyl acrylate; 3-chloro-2~hydroxy-
propel acrylate; 2-hydroxy-1-methylethyl acrylate;
2-hydroxypropyl acrylate; 3-hydroxypropyl acrylate;
2,3 dihydroxypropyl acrylate; ~-hydroxybutyl acrylate;
4-hydroxybutyl acrylate; diethylene glycol acrylate;
5-hydroxypentyl acrylate; ~-hydroxyhexyl acrylate;
triethyleneglycol acrylate; 7-hydroxyheptyl acrylate;
2 hydroxymethyl methacrylate; sheller hydroxypropyl
methacrylate; 2-hydroxy-1-methylethyl methacrylate;
2-hydroxypropyl methacrylate; 3-hydroxypropyl
Inethacrylate; 2,3-dihydroxypropyl methacrylate;
2 hy~roxybutyl methacrylate; 4-hydroxybutyl methacrylate;
3,4-dihydroxybutyl methacrylate; 5-hydroxypentyl
me~hacrylate; 6-hydroxyhexyl methacrylate; 1,3-dimethyl-
3-hydroxybutyl methac~ylate; So dihydroxyhexyl
methacrylate; and 7-hydroxyheptyl methacrylate.
Although one of ordinary skill in the art will
recognize that many different hydroxyl bearing monomers,
including those listed, above could be employed, the
preferred hydroxy functional monomers for use in the
copolymer of the invention are C5 C7 hydroxy alkyd
23~3
acrylates and/or I C8 hydroxy alkyd methacrylates,
i.e., esters of C2 I dihydric alcohols and acrylic or
methac~ylic acids.
Except in those instances wherein a specific
compound is nalned, the term "acrylate" is used in this
specification to include esters of both acrylic and
,nethacrylic acid, i.e., acrylates and methacrylates~
Tune remainder of the monomers forming the
copolymer, i.e., between about ox and about 90 weight
percent of the monomers of the calmer, are other
monoethylenically unsat~rdted monomers. These other
monoethylenically unsaturated monomers are preferably
alpha-beta olefinically unsaturated monomers, i.e.,
monomers bearing olefinic unsaturation between the two
I cacborl Tunis in the alpha and beta positions with respect
to the tec!ninus of an aliphatic carbonate carbon chain.
non the alpha-beta olefinically unsaturated
monomers winch may be employed are other acrylates
(meaning es'~ecs of either acrylic or methacrylic acids not
containing glycidyl or hydroxyl functionality), as well as
mixtures of these other acrylates and other monovinyl
hydrocarbons. Preferably, in excess of 50 weight percent
of the total of the copolymer monomers are acrylates (this
total including lucidly acrylates, hydroxyl functional
~crylates and other acrylates). These other acrylates are
preferably selected from esters of Of - C12 mandrake
alcohols and acrylic or methacrylic acids, i.e., methyl
methacrylate, ethylacrylate, butylacrylate, (iso)-butyl-
met'nacrylate, hexylacrylate, 2-ethylhexyl acrylate,
laurylmethacrylate, etc. Monovinyl hydrocarbons when they
are employed, should preferably constitute less than 50
weight percent of the copolymer. Among the monovinyl
hydrocarbons suitable for use in forming the copolymers
are those containing 3 to 12, preferably 8 to 12 carbon
atoms and including styrenes alpha methylstyrene, vinyl
Tulane, t-butylstyrene and chlorostyrene. Other such
- 8
monovinyl monomers such as vinyl chloride, acrylonitrile,
methacrylonitrile, and vinyl acetate may be included in
the copolymer as modifying monomers. However, when
employed, these modifying monomers should constitute only
between about O and about 30 weight percent of the
monomers in the copolymer. Small amounts of ethylenically
unsaturated carboxylic acids can also be used in preparing
thy copolymer, such as acrylic Acadia methacry].ic acid,
crotonic acid, itaconic acid, malefic acid and the like.
lo The copolymer preferably contains at least about
3 functional groups per molecule based on epoxide and
hydroxyl functionality. The copolymer of the coating
composition most preferably contains a total of about S
functional groups (ire., epoxide and hydroxyl. functional
groups) per molecule, erg./ 3 epoxies and 2 hydroxy:l
groups, or 4 hydroxyl and l epoxide groups
A preferred embodiment of this invention
comprises a copolymer of glycidyl methacrylate~
hydroxyethyl methacrylate, isobutyl methacrylate and
styrenes
In preparing the copolymer, the epoxide
functional nonhumorous, the hydroxy functional monomers, and
the remaining monoethylenically unsaturated monomers are
mixed and reacted by conventional tree radical initiated
polymerization in such proportions as to obtain the
copolymer desired A large number of free radical
initiators are known to the art and are suitable for the
purpose. These include: bouncily peroxide; laurel
peroxide; t-butylhydroxy peroxide; acetylcyclohexyl-
sulfonyl peroxide; diisobutyryl peroxide; di(2-ethylhexyl)
peroxydicarbonate; diisopeopylpeeoxydicarbonate;
t-butylperoxypivalate; decanoyl peroxide; azobis
(2-methylpropionitrile), etc. The polymerization is
preferably carried out in solution using a solvent in
which the epoxide-functional, hydroxylfunctional copolymer
is soluble. Included among the suitable solvents ace
~3g~
g
Tulane, methyl Amy kitten, zillion, Dixon, butanone,
etc. If the epoxide-functional, hydroxy-functional
copolymer is prepared in solution, the solid copolymer
can be precipitated by pouring the solution at a slow
rate into a nonsolvent for the copolymer such as hexane,
octane, or water under suitable agitation conditions.
The copolymer useful in the compositions o-f
this invention can also be prepared by emulsion
polymerization, suspension polymerization, bulk
polymerization, or combinations thereof, or still other
suitable methods. In these methods of preparing
copolymers~ chain transfer agents may be required to
control molecular weight of the copolymer to a desired
range. When chain transfer agents are used, care must be
taken so they do not decrease the shelf stability o-f
the composition by causing premature chemical reactions.
Various mixtures of these types of copolymers
may also be employed within the scope of the
compositions of the invention described herein.
(B) D1carboxylic Acid Android
The android used in this composition
comprises at least 50 percent by weight, and up to 100
percent by weight, of alkyd hexahydrophthalic android,
wherein the alkyd group preferably comprises up to about
7 carbons, more preferably up to 4 carbons. Most
preferably the alkyd hexahydrophthalic android
comprises methyl hexahydrophthalic android. The
remainder of the androids, Leo 0 to about 50 weight
percent, more preferably 0 to about 20 weight percent,
and most preferably 0 to about 10 percent by weight, are
selected from a variety of androids, which include but
are not limited to, hexahydrophthalic, 2-dodecene-1-
ylsuccinicr tetrahydrophthalic, methyl
tetrahydrophthalic and camphoric androids, and
mixtures of suitable androids.
10~ I
The android is included in the composition in
an amount sufficient to provide between about 1.0 and
about 1.2, more preferably about 1.0 anhydrlde equivalents
per pendant epoxide group initially present on the
copolymer~ During curing, it appears that the android
reacts with hydroxyl groups on the copolymer forming
carboxyl groups. In compositions wherein excess android
(iOeu, relative to hydroxyl groups) is present, it appears
that the excess android will later react with the
hydroxyl groups generated ho subsequent carboxyl/epoxide
reactions to form more carboxyl groups Since epoxide is
present in an amount substantially corresponding to the
android, these carboxyl groups will subsequently be
reacted with epoxide to form (ire., regenerate) hydroxyl
Functionality
Catalysts are generally included in the
composition to accelerate the epoxide/carboxyl reaction.
Suitable catalyst for this epoxide/carboxyl reaction are
well known in the art Preferred catalysts useful for
this reaction are the tetralkyl ammonium salts such as
twitter methyl ammonium chloride, tetraethyl ammonium
bromide and trim ethyl bouncily ammonium chloride as well as
metal salts of a carboxylic acid, such as potassium
octet or chromium III octet. Other useful catalysts
include metal halides such as chromium trichloride,
ferris trichloride, and aluminum trichloride; mercaptans
and thioethers such as octal mercaptan, demarcate
propanol and dimercapto-diethyl ether; tertiary amine
sun as triethyl amine, pardon, dimethylandine,
quinolinel -picoline, ethylpyridine, and the like. Still
owner catalysts known to catalyze the carbo~yl/epoxide
reaction will be apparent to those skilled in this art.
~L~3~;230~3
11
(C) amino Crosslinkinq Agent
Another essential component of the paint
compositions of this invention is an amine-aldehyde
cross linking agent. Amine-aldehyde cross linking agents
suitable for cross linking hydroxy functional bearing
materials are jell known in the art. Typically, these
cross linking materials are products of reactions of
mailmen, or urea with formaldehyde and various alcohols
containing up to and including 4 carbon atoms.
Preferably, the amine~aldehyde cross linking agents
useful in this invention are amine-aldehyde resins such
as condensation products of formaldehyde with mailmen,
substituted mailmen, urea, benzoquanamine or
substituted benæoquanamine. Preferred members of this
class are methylated melamine-formaldehyde resins such
as hexamethoxylmelamine. Those liquid cross linking
agents have substantially 100 percent nonvolatile
content as measured by the foil method of 45C for 45
minutes. For the purpose of the preferred high solids
coatings of the invention it should be recognized that
it is important not to introduce extraneous delineates
that would lower the final solids content of the
coating. Other suitable amine-aldehyde cross linking
agents would be apparent to one skilled in the art.
Particularly preferred cross linking agents are
the amino cross linking agents sold by American Cyanamid,
Wayne, NO under the trademark "Camel". In particular,
Camel 301, Camel 303, Camel 325 and Camel 1156, which
are alkylated melamine-formaldehyde resins, are useful
in the compositions of this invention.
The cross linking reactions are known to be
catalytically accelerated by acids. Therefore, the
unconsumed carboxyl groups acts as a catalyst for the
cross linking reaction. In addition, if desired,
catalysts may be added to the composition which
accelerate the
I
crosslir.king reaction. One such catalyst, for example! Is
Tulane sulfonic acid and the amine salts thereof.
Other useful catalysts are well known to one skilled in
the art. Selection of optimal cure temperature would be
well within the skill of one in the art. The
amine-aldehyde materials function as a cross linking agent
in the composition of the invention by reacting with the
llydro~yl groups of the composition which groups were
either present initially on the copolymer and non reacted
or regenerated during subsequent in situ reactions of
initially present hydroxyl groups
In order to achieve the outstanding properties
which make these coating compositions particularly useful
as automotive topcoat materials, it is essential that the
amount of amino cross linking agent be sufficient to
substantially cross link the hydroxyl groups in the coating
composition. Therefore, tune amino cross linking agent
should be included in the composition in an amount
sufficient to provide at least about 0.60, preferably
between about 0.75 and about 2~75, groups of nitrogen
cross linking functional group for each hydroxyl group
included in the composition either as an initially present
and unrequited 'nydroxyl group on the coupler or as a
regenerated hydroxyl group iOeO, by means of in situ
I reactions with android and epoxy. The hydroxyl groups
present in the composition and available for cross linking
can therefore be essentially taken to be equal to hydroxyl
gruels initially present on the copolymer (A).
(D) Solvent
It is generally suitable and preferable, in order
to achieve the preferred high solids content of the
coating compositions of the invention, to use little
~23~2~3
- 13 -
solvent in the composition. Suitable solvents which may
be employed include those commonly used, such as
Tulane, zillion, methyl Amy kitten, acetone, bottle
acetate, tetrahydrofu ran, ethyl acetate,
dimethylsuccinate, dimethylglutarate, dimethyladipate or
mixtures thereof. The solvent, in which the hydroxy
glycidyl acrylic copolymer is prepared, may be employed
as a solvent for the coating composition thus
eliminating the need for, drying the copolymer after
preparation, if such is desired.
As mentioned above, the nonvolatile solids
content of the coating composition is preferably at
least 60% and more preferably 70% or more, thus limiting
the amount of solvent included in the composition.
However, while the composition is particularly suitable
for use as a high solids composition, the composition is
also suitable for use as low solids compositions.
Determination of optimal solids content for a given
application would be within the skill of one in the art.
Other Materials
In addition to the above discussed components,
other materials may be included in the coating
compositions of the invention. These include materials
such as catalysts, antioxidant, U.S. absorbers,
solvents, surface modifiers and wetting agents, as well
as pigments.
Surface modifiers or wetting agents are common
additives for liquid paint compositions. The exact mode
of operation of these surface modifiers is not known,
but it is thought that their presence contributes to
better adhesion of the coating composition to the
surface being coated and helps formation of thin
coatings, particularly on metal surfaces. These surface
modifiers are
~3~i,7'~'3~
exemplified by acrylic polymers containing Sol - 10
percent by weight of copolymerized monoethylenically
unsaturated carboxylic colds such as methacrylic acid,
acrylic acid or itaconic acid, cellulose acetate bitterroot,
silicone oils or mixtures thereof. Of course, the choice
of surface modifiers or wetting agent is dependent upon
the type of surface to be coated and selection ox the same
is clearly within the skill of the artisan.
The coating composition of the invention also
may include pigments. The amount of pigment in the coating
composition may vary, but preferably is between about 3
and about 45 weight percent based on the total weight of
the pain composition. If the pigment is metallic flake,
the amount generally ranges from about 1 to about 20
weight percent.
For many applications of the coating compositions
of this invention, particularly high solids compositions,
it may be desirable to employ flow control additives to
provide sag free coaxings. Among numerous such materials,
Nudes such as described by Porter (S. Porter, Jo. and BUN.
Mc8ane, U.S. Patent 4,025,474, May 24, 1977) are come
partible with these coating compositions. these particle
dispersions may be included in an amount up to 15% by
weight of the total composition. Other types of Nudes
such as described by DO Maker and SAC. Ping (U.S.
Patent 3,814,721, June 4, 1974 or by SKYE. Horvath (U.S.
Patent No. 4,415,681) also may be included in the paint
composition.
Application Techniques
The coating composition can be applied by
conventional methods known to those skilled in the art.
These methods include roller coating, spray coating,
dipping or brushing and, of course, the particular
- 15 -
application technique chosen will depend on the particular
substrate Jo be coated and the environment in which the
coating operation is to take place.
A particularly preferred technique for applying
the high solids coating compositions, particularly when
applying the same to automobiles as topcoats, is spray
coating through the no to of a spray gun.
High solids paints have in the past caused some
difficulty in spray coating techniques because of the high
viscosity of the materials and resultant problems in
clogging of spray guns. However, because the compositions
of this invention demonstrate relatively KIWI ViSCSitYt
considering the high solids content, they can be applied by
spray coating tuitions
The invention will be further understood by
referring to the following detailed examples. It should be
understood that the specific examples are presented by way
of illustration and not by way of limitation. Unless
otherwise specified, all references to "parts" is intended
to mean parts by weight.
Example 1
In a round-bottom four necked flask, equipped with
a stirrer, a dropping funnel, a thermometer and a
condenser, 500 ml methyl Amy kitten is brought to reflex
under nitrogen. The following mixture of monomers is
employed for polymer synthesis:
Wt./gms White
Bottle methacrylate 300 40
Glycidyl methacrylate 210 28
Hydroxyethyl methacrylate 45 6
Methyl methacrylic 195 26
I
-- 16 -
Thirty-seven (37) grams of tertobutyl perbenzoate
are added to -the above monomers and the resulting solution
added drops to refluxing methyl Amy kitten over a
period of one hour and 20 minutes. The heating and
stirring is continued for half an hour after the addition
is complete and then one more gram tert-butyl perbenzoate
is added portions to the reaction mixture. The reaction
mixture is reflexed for two more hours and theft allowed to
cool to zoom temperature. The molecular weight of the
polymer is determined by gel permeation chromatography rid
found to be on = 33~0 and Winnie = 2-1-
Seventy-five (75) parts of Camel 3~5 (American
Cyanamid Wayne, NO 0.75 parts of Cordovan Accelerator
AMCTM~2 (Cordovan Chemical, Sacramento, Calico) and 17 parts
of bottle acetate. Fourteen (14) parts of
methylhexahydrophthalic android are added to the above
solution and the resulting composition it applied by
spraying to primed steel panels. The panels are baked at
135C for 18 minutes to obtain coatings with excellent
hardness, adhesion and solvent resistance.
Example 2
In a two liter round-bottom flask, equipped with a
stirrer, a condenser and a dropping funnel, 750 ml Tulane
is heated to reflex under nitrogen. The following mixture
of monomers containing 15 grams of
2,2'-azobis-(2-methyl-proprionitrile) dissolved in 50 ml
acetone, is added drops to the refluxing Tulane.
Wt./gms Wt./%
iso-Butyl methacrylate 210 70
Glydicyl methacrylate 45 15
Hydroxypropyl methacrylate 45 15
- 17 - 'I ~3~3~
The addition of the initiator and monomer solution
is completed in three hours. The reaction mixture is
reflexed for half an hour and a 10 ml acetone solution of 2
grams of the above initiator is added drops and the
reaction mixture reflexed for one hour. Part of the
solvent is distilled off to bring the solids content to 62%
by weight.
Fifty (50) parts of the above polymer solution, 19
parts of Camel 325 and 0.6 parts of Cordovan Accelerator
AMCTM_2 (Cordovan Chemical, Sacramento, Calif.j are
dissolved in 14 parts of methyl Amy kitten and OWE parts
of methylhexahydrophthalic android are added to the above
solution. The resulting composition is applied by spraying
to primed steel panels which are baked at 130C for 18
minutes to obtain hard, glossy coatings with excellent
adhesion and solvent resistance.
Example 3
A copolymer is prepared by following the procedure
described in Example 1 in methyl Amy kitten and by using
the following monomers:
it. %
Bottle methacrylate 50
Ethylhexyl acrylate 10
Glycidyl methacrylate lo
Hydroxypropyl methacrylate 10
Methyl methacrylate 10
Styrenes 5
Tert-butyl peroctoate (5.25% of monomers) is used
as initiator and determined solids content is 63~ by
weight
- 18 ~3~2~
A mill base is prepared by dispensing Shea in the
above polymer with a high speed Cowl's blade. The
composition of the mill base is: polymer 15~, Shea 65% and
methyl Amy kitten 20%.
Forty-two (42) parts of the above mill base are
mixed with 27 parts of the polymer solution, 11 parts of
Camel 325~ 0.55 parts of Cordovan Accelerator ~MCTM 2 and 12
parts of n-bu~.yl acetate. Four (4) parts of
methylhexahydrophthalic android are added to the above
10 formulation and the resulting composition is applied by
spraying to primed steel panels The panels are baked at
130C for lo minutes to obtain white coatings with
excellent physical properties.
Example 4
A glycidyl hydroxy polymer of My = 2900 is
prepared from glycidyl methacrylate (20~), hydroxyethyl
methacrylate (10%) isobutyl methacrylate (65~) and styrenes
I ion refluxing methyl Amy kitten (59%) nonvolatile
as described in Example 1.
Twenty-one (21) parts of the above polymer
solution, six parts of Camel 325 and 1 drop of Cordovan
Accelerator AMCTM~2 are dissolved in 8 parts of bottle
acetate. Methylhexahydrophthalic android (2.9 parts) is
added to the above solution and the resulting formulation
is drawn on a primed panel which is baked at 130C for 17
minutes to obtain coatings with excellent zillion and methyl
ethyl kitten resistance.
3~3
-- 19 -
Example 5
Eight (8) parts of aluminum flakes (65~ in
naphtha) and 15 parts of flow control additive prepared
according to U.S. Patent 4,025, 474r are added to the
polymer/melamine component described in Example 1 and the
mixture is placed on a shaker for one hour Fourteen I
parts of methylhexahyydrophthallc android are added to
the above composition and resulting formulation is applied
by spraying in three coats to primed steel panels The
panels are flashed for five minutes at room temperature and
baked for 18 minutes at 130~C to obtain silver metallic
coatings with excellent hardness, adhesion and solvent
resistance
In the composition described in Example 2, a
solution of 1.9 parts adipic android in 3u5 parts of
methylhexahydrophthalic android is added instead of the
android employed therein. The resulting composition is
applied by spraying to primed steel panels which are baked
at 130C for 18 minutes to obtain hard, glossy coatings
with excellent adhesion and solverlt resistance.
Example 7
A copolymer is prepared by following the procedure
described in Example 1 yin methyl Amy kitten and by using
the following monomers:
I
- 20
White/%
Bottle methacrylate 45
Ethylhexyl acrylate 8
Glycidyl methacrylate 15
Hydroxypropyl methacrylate 15
Methyl methacrylate 10
Vinyl acetate 7
Tert~butyl Ferbenzoate (5% of monomers) is used as
initiator and determined solids content is 62%.
ICKY Fifty five (55) parts of this polymer solution,
19.5 parts of Camel 325 and 0.6 parts of Cordovan
Accelerator ~MCTM 2 are dissolved in 15 parts of bottle
acetate and 6 parts of methylhexahydrophthalic android
are added to this solution. The resulting composition is
applied by spraying to primed steel panels which are baked
at 130C for 19 minutes to obtain coatings with excellent
physical properties.
Example 8
A copolymer is prepared by following the procedure
2Q described in Example 1 in methyl Amy kitten from the
following monomers.
White
Ally alcohol 5
Bottle methacrylate 50
Glycidyl methacrylate 15
Hydroxypropyl methacr~late 15
Methyl methacrylate 15
Tert-butyl peroctoate (5.1% of monomers) is used
as initiator and solids content is 62.5%.
I
- 21 -
Fifty (50) parts of this polymer solution, 18
parts of Camel 301, 0.5 parts Cordovan Accelerator AMCTM-2
and 0.2 part of Tulane sulfonic acid are dissolved in 17
parts of bottle acetate. Methylhexahydrophthalic android
(5.5 parts) is added to the above solution and the
resulting composition is applied by spraying to primed
steel panels. The panels are baked at 130C for 19 minutes
to obtain coatings with excellent physical properties.
It will be obvious from the foregoing that this
invention has industrial applicability, particularly to the
automotive industry, and provide a coating with excellent
exterior weather ability and distinct commercial advantages.
