Note: Descriptions are shown in the official language in which they were submitted.
7ZZ3Z ~: :
;
Bac~Lround o~ the Invention
D recent times, the:increa ed emphasis on environmental pollu-
: tion probIems has a~fected all areas o~ society~ In the coatings lndustry,:
~ ~ thls mphasis has taken the form of a major ef~ort to el~inate or substan-.
. ~
tially reduce~organic sol~ent ~m~s~io~3 ~rom coa~ing composltions. This ~
has led to an increasing intexest ,on ~he part o~ the coat~ngs industry ~ :in water~baJed coatin~g ~n wh~h. oxganic 801vent6 are eliminated or at . :
~leas~ greatly reduced~ In even more ~ecent tl:mes, this interest in water- -
; based COJtingS has received added impetus as a result of the energy:shortage, .:
. .
~:, ~ ''~
~ 1 -` ' .
;. . , . .. ,. . ~ . . , ~ ... : ~
1~7223~
particularly the decline in U~S~ oil production and the high cost of
imported oil~
~ ater-based coating compositions derived from interpolymers of
substituted, unsaturated carbox~lic acid a~ides, alpha, beta-ethylenically
unsaturated carboxylic acids, and other ethylenically unsaturated monomers
are known in the art, e~g~, see U.S~ ~atent ~o. 3,247,139 issued April 19,
1966, and Example X~ of U~S~ ~atent ~o~ 3,079,434, issued February 26, 1963.
However, the water-based coating compositions of the aforementioned patents
differ materially in composition from the compositions of this invention in
that the compositions therein do not contain either a polyol component or an
aldehyde condensation resln~ ~oreoVert while the compositions of .
these patents are useful in certain applications, they have been found to
exhibit a number of serious disadvantages which materially limit their -.
usefulness~ Thus, the compositions of the aforementioned patents and, for
that matter, water~based coatings in general? have been found to be very
susceptible to solvent or water popping and sagging, or "curtaining`',
particularl~ when relatively thick films are deposited therefrom. Solvent
or water popping manifests ltself.in the Porm of bubbles or pinholes in the
cured film surface.
~ The exact cause oP solve~t or water popping is not known with -
certitude, but it has been theori~d that the film sets up structurally,
or actually begins to crosslink before the last portion of the solvent or
water is eliminated~ This residual solvent or water cannot evaporate through
the tough surface film, and collects in tiny bubbles which may or may not
rupture, depending upon t~e curing conditions~ _
nother theo~ i3 th~ ~S. the ~es~n cures? the water ~nd~or
alkanol given of~ during t~e c~osslink~ng cure process ~s actually entrained
under the film surface i~ t~e Porm. o~ tiny bub.bles~
2 -
': . ' , ,' ~ :' , . :
~ 7ZZ3Z
Sagging or "curtaining~' occurs ~hen relatively thick films of the
coating composition are applied to other than horizontal sur~aces and is
due to gravitational flo~ of the film, and/or to film resoftening during
the curlng period~ In the coatings art, ~he term "sagging" denotes the
tendency of a film to drain o~ ~low ~rom a non~horizontal surface in an
uneven manner, while the term '~curtaining~`denotes ~he tendency of the fllm
to drain or flow from said su~face in a smooth, continuous manner.
Water-based coating compositions such as those described in the
aforementioned patents also exhibit additional disadvantages. Thus, such
compositions have been found to have ~nadequate moisture and detergent
resistance ~or certain coating applications, such as~ for example, coatings
~or ~ashers, dryers and the like.
Very recently, water-based coat;ing compositions comprising
methylolated amide interpolymers of hlgh acid content and low molecular
weight polyhydric alcohols ha~e been disclosed in U~S. Patent No. 3,860,549
to Sek~akas, issued ~anuary~14~ 1975~ However, the compositions of the patent
are speci~ic to interpolymers derived from unetherified methylolated amldes
and also do not contain aldehyde condensation resins, and this differ materially
~rom the compositlons o~ this invention~ The compositions of the aforementioned
patent also exhibit ssrious disadvantages~ Thus, compositlons based upon -
methylolated amide interpolymers tend to exhibit short potlife and be prone to
gelation~ Additionally, compositions o~ the type described ln Sekmakas also
exhibit inadequate moisture and detergent resistance in certain coating
applications, such as, for example, coat~ngs for washers9 dryers and the like.
In accordance with thls ln~ention, a ~ater-baséd coating composition
~s prov~ded ~hich overcome6 s~bs~antiall~ all of the dlsadvantages ~e~erred
to above~ Thus; the w~ter~b~sed coat~ng composition of the invention is one
in which solvent popping or water popping and sagging is eliminated or at least
s~bstantially reduced~ ~oreover~ t~e composi~ions of the invention are based
~ 3 ~
.
' ', ' . ' . ' .'~
~L~7Z;Z32
upon etherified amide interpolymers ~discussed below) and hence have excellent
stability. Finally, the compositions o~ the invention form ~ s having
improved water, salt spray~ detergent and stain resistance.
~ .
Descrlption of t~e lnvention
The water-based coati~ng compositions of the invention comprise
a thermosetting, film-forming organic blnder dis~exsed in an aqueous medium
containing from 60 to 100 parts by weight of water and 0 to 40 parts by
~eight o~ a volatile organic solvent~ The water-.reducible organic binder
o~ the composition is for~ulated from GA) an acid~ccntaining interpolymer
adapted to be dissolved or dispersed in water with the aid of a base and
CB~ a water-soluble or water-dispersible polyether polyol or polyester
polyol having a molecular weight o~ at least about 300.
The properties o~ coatings fo~med fro~ the compositlons can be
further enhanced (i.e., improved) if desired by incorporating (C) a water-
soluble or water-dispersible ald.ehyde condensation resin into the organic binder.-
(~ T'ne ~cid-Containing Interpolymer Component
The interpolymer component of the compositions of the invention
N' .
consists essentially o~ the interpolymerization product of an-a-alkoxyalkyl-
substituted amide, an alpha, beta-ethylenically unsaturated carboxylic acid
and at least one other monomer con~aining a CH2 = C ~ group.
The N-alkoxyalkyl-substi~uted amides e~ployed in for~ing the
interpolymer hereln may be~epresented by the structure:
~ .
R~ - C ~ ~H ~ CH~ ~ O ~ R
~ 4 ~
.
~7223%
wherein R' is an aliphatic hydrocarbon radical containing from 2 to 6 carbon
atoms and having a single polymerizable alpha, beta-ethylenically unsaturated
group and R is a lower alkyl radical containing from 1 to 8 carbon atoms.
These substituted amides can be prepared by reacting an unsaturated
amide (e.g., acrylamide) with formaldehyde and an alkanol (e.g., butanol) under
acidic conditions and in the presence of a polymerization inhibitor. For a
detailed description of this method, see U.S. Patent No. 3,079,434. The
resultant N-alkoxyalkyl-substituted amide Ce.g., N- (butoxymethyl)acrylamide~
is then interpolymerized with the other monomers (described below) to form the
interpolymer containing the substituted amide units.
The preferred N-alkoxyalkyl-substituted amide employed in formin~ the
interpolymer is N-(butoxymethyl)acrylamide, although other N-alkoxyalkyl
substituted unsaturated carboxylic acid amides such as N-(methoxymethyl)-
acrylamide, N- (propoxyme-thyllacrylamide, N-~ isopropoxymethyl)acrylamide, N-(iso-
butoxymethyl)acrylamide and N- (butoxymethyl)methacrylamide, or the like may be
employed.
The interpolymer may contain in polymerized form from about 10 to
about 40 percent by weight of these N-alkoxyalkyl-substituted amides with a
preferred range being from about 20 to about 30 percent.
Alpha/ beta-ethylenically unsaturated carboxylic acid monomers which
are preferably utilized in forming the acid units of the interpolymer include
acrylic or methacrylic acid but itaconic acid, crotonic acid, maleic acid and
half esters of maleic and fumaric acids may also be used. In the half esters,
one of the carboxyl groups is esterified with an alcohol, the identity of which
is not significant so long as i.t does not prevent polymerization or preclude
the desired utilization of the pxoduct. Butyl hydrogen maleate and ethyl
hydrogen maleate are examples.
.
- 5 -
' . ' : :
3L~72~32
The interpolymer ~ay contain in polymerized form from about
5 to about 20 percent by weigh~ o~ suc~ ~cld units. Howeve~ ~or
greater efficiency in solubilization and overall properties, it is
preferred that from 7 to 15 percent of such acid units be present in
the interpolymer.
As indicated, the interpolymer? in addition to the substituted
amide and acid units, contains units of at least one other monomer contain-
ing a CH2 = C ~ group. The other monomer containing the CH2 = C < group can
by any ethylenically unsaturated compound which is copolymerizable with
the substituted amide and acid with the polymerization taking place
through the ethylenically unsaturated linkages~ These include monoolefinic
and diolefinic hydrocarbons, unsaturated esters of organic and inorganic
acids, esters of unsaturated acids and unsaturated organonitriles such
as acrylonitrile and the like~ It is preferred, in order to provide
desirable properties in the interpolymer~ to utilize a combination
of hardening and flexibilizlng monomers. The preferred hardening
monomer is styrene, but others such as vinyl toluene or alk~l methacrylates
having from 1 to 4 carbon atoms can also be utilized~
The interpolymer may contain in polymerized form from about
5 percent to about 75 percent by weight of hardening monome~s with a
preferred range being from about 50 to about 60 percent of such monomers.
The flexibilizing monomers u~ilized may be one or more alkyl
or substituted alkyl esterg of acrylic or methacrylic acid, the alkyl groups
having 1 to 13 carbon atoms in the case of acrylic esters and 5 to 16 carbon
atoms in the case of methacrylic esters~ Illustrati~e of such flexibilizing
monomers are ethyl acx~late~ ~UtY~l ~cr~late, 2~ethylhexyl acrylate~ 2-ethyl-
hexyl methacrylate, decyl ~ethacr~late, l~uryl methac~ylate, and the like.
~ 6 ~
~i72,232
The irlterpolymer ma~ contain~ in polymerized form, from about 5
percent to about 75 percent b~ wei~t of such ~lexibili~ing mono~ers with
a preferred range being ~rom about 20 pe~cent to about 50 percent~
~ The above-described acid-containing interpolymer is prepared by
conventional vinyl polymerization technlques utilizing ~inyl polymerization
catal~æts which are well known in the art~ These include the azo compounds
such as alpha, alpha~azobis(isobutyronitrile), which are the preferred
~atalysts herein, and the well known peroxygen catalysts such as benzoyl
peroxide, lauroyl peroxide, cumene hydroperoxide and the like. Other useful
catalysts include tertiary-bu~yl perbenzoate, tertiary-butyl pivalate, ~-
isopropyl percarbonate and similar compounds. In addition~ the interpolymer
may be prepared, if desired, by conventional emulsion polymerization
techniques. In that e~ent, it is often desirable and preferred to employ
water-soluble initiators such as hydrogen perox`ide, ammonium persulfate,
potassium persulfate and other similar persuIfates.
As indicated, ~he above-described acid-containing interpolymer is
adapted to be dissolved or dispersed in an aqueous medium with the aid of a
base. This is accomplished by neutralizing alI or a portion of the carboxylic
acid groups of the interpolymer with an appropriate base. Virtually any ;~
basic compound can be utilized ~or that purpose, including inorganic bases
such as alkali metal hydroxides and organic bases such as amines. However,
the preferred basic compounds utilized herein are the monomeric amines. These
may be any of the a~ines used ~or solubilizing pUxposes known hereto~ore,
including ammonia, ethylamine~ butylamine, dimethylamine, cyclohexylamine,
morpholine, monoethanolamineS d~ethanolamine~ dimethylethanolamine, diethyl- -
ethanolamine and the l~he~ 0~ these amines, di~e~hylethanola~ine is pre~erred~ -
The amount o~ a~ne employed i~ neutralizing the acid groups of the
interpolymer may ~ary considerabl~ Howe~er; i~ is preferred in this invention
7 ~
~7~Z,232
tllat the amount of amine employ~d be su~icient to neutralize at least
about 40 percent o~ the theoretical quantity of acid groups p~esent
in the interpolymer~
~ Several procedurefi may be emploved in dispersing the inter-
polymer in the aqueous medlu~ One known method is to first ~orm the
interpolymer in solution by polymeri~ng the monomers in a water-miscible
volatile organic sol~ent or mi~ture of suc~ solvents, following which
the acid groups of the resultant interpolymer are neutralized with the
basic compound, if deslred~ in the pre~ence of water~ to form the salt
or partial salt of the interpolymer, thus enabl~ng the interpolymer to
be dissolved or dispersed in the aqueous medium. In this method~ any
excess organic solvent utili~ed i~ the polymeri~ation process can be
removed from the aqueous medium by dlstillation if desired. Alternatively,
in the practice o~ this invention, the monomers can firs~ be polymeri~ed
in a mixture of ~ water-mlscible ~olat~le organic solvent and the water- -
soluble or ~ater-dispersible polyether or poIyester polyols (described
hereinafter~ or in the water-soluble or water-dispersible polyether or
polyester polyol alone, following whlch the acid groups o~ the resultant
interpolymer are neutrallzed to form the salt or partial salt of the
interpolymer, thereby rendering the interpolymer dissolvable or dispersible
in the aqueous mediu~ ~hese alternative procedures have t~e advantage
of eliminating the necessity for a separate distillation step to remove .
any excess organic solvent~
Yarious water-miscible or wate~soluble organic solvents can
suitably be employed in producing the water~soluble or water-dispersible
interpolymer~ ~us~ th.e ether t~pe ~lc0~018 such as ethylene glycol
monobutyl ether (i~e~, but~l Cellosolre~,.eth~lene glycol monoethyl ether
~'~ ~k
-~8 ~
. ~ , ..
~ZZ32
(i.e , ethyl Cellosolve~, dlethylene glycol monomethyl etherg diethylene
glycol n-butyl ether (i.e. 3 butyl Carbitol~ and the like may be advantageously
employed~ In addition, lower alkanol~ ha~ing 2 to 4 carbon atoms such
as ethanol, propanol9 ~sopropanol~ Butanol and the like can be used.
Mixtures of the ether type alcohols and lo~er alkanols are often advan- - -
tageously employed. ~inor proportions of ~drocarbon solvents such as
Y~ylene, toluene and the like may also be included.
The liquid portlon o~ ~he coating compositions herein may
contain from about 60 to about 100 percent by weight o~ water and
correspondingly from 0 to about 40 percent by weight of organic solvents,
such as those mentioned above, with a preferred ratio being from 80 to 90
percent by weight of water and 10 to 20 percent by weight of organic solvent.
In any case, at least about 6Q percent by~weight of the liquid medium will
be water.
C~2 The ~ater~Soluble o~ ~ater-Dispersible Polyol-Component
As indicated above, in addition to the previously-described
interpolymers, the organic binder of the water-based coating compositions
of the invention contains a non-volatile, water-soluble or water-dispersible
polyether polyol or polyester polyol~
Polyether polyols or polyester polyols which can suitably be
employed in the binder of the compositions of this invention are those
havlng a molecular weight of at least 300 and which are soluble or disper-
sible in water. These polyols must have molecular weights of at least 300
and may have molecular weights of up to 5000 or even higher~ provided they
are water-soluble or water~di`spexsible~ ~he preferred water~soluble or
water-dispersible polyet~e~ polyo~s ox polyester polyols employed in the
compositions o~ t~e inventio~ are those h~v~ng molecular weights of from
C~ trk
_ 9 _ ~
, , ,
... .. . . . . .
. : . , ~ . . ~ ,
~72232
about SOO to about 3000~ As fuxther stated~ the polyols employed must
be non-volatile. The term "non~volatilel' as applîed to the polyols
herein means that under the curing conditions utilized, not more than
5^percent of the polyol w~ll volatilize, C~e~? evaporate) from the
film, before the film is cured~ ~
Subject to the above li~itations, essentially any polyether
polyol or polyester polyol can be e~ployed in the compositions of the
lnvention, with the preferred polyols being polyether polyols which are
the reaction products of an alkylene oxide, preferable ethylene oxide
or 1,2-propylene oxide, with a polyol such as glycerine, trime-thylol-! -
propane, hexanetriol, pentaerythritol, sorbitol~ sucrose or the like.
The particularly preferred polyether polyols used in the invention
are the reaction products of 1,2-propylene oxide with a mono- or disaccharide
such as sucrose? dextrose~ lactose and alpha-methyl d-glucoside~
Polyethers of mono- and disaccharides are known in the art~ -
One prsferred method o~ preparlng these sugar-containing polyether polyols
(e~g., sucrose polyether polyol~ is to ~irst dissolve the saccharids In
water, following wh~ch an oxyalkylation catalyst is added, and the alkylene
o~ide addition is carried out to that point at which the saccharide-alkylene
oxide reaction product is a liquid at roo~ te~perature. At this point,
substantially all of the ~ter present is re~oved by distillation or other
means~ and the balance o~ the alkylene oxide is added until the desired
polyether polyol is obtained~ For a detailed description of these saccharide-
containing polyether polyols and their method o~ preparation~ see U~S. Patent
No. 3,085,085, issued April 9~ 1963~ -
Polyester polyols ~hl~h are sultable ~or use. in the instant
Invention a~e ~ormed from the pol~este~ication of organic polyols and
organlc polycarboxylic acids or acld anhydrlde~ The polyols and poly-
a ~
, . . ~ . :
. .
~L~7Z~32
carboxylic acids or anhydrides are often aliphatic or aromatic diolsand diacids but i~ is advantageous ~ o~e cases to employ polyols or
polycarboxylic acids having hydrox~l or carboxyl functionalities of 3
or more.
The pre~erred polyols e~ployed i~ formi~g the polyesters
are diols and triols~
Diols which may be employed in making the polyester polyol
include alkylene glycols such as eth~lene glycol, propylene glycol,
butylene glycol, h OEylene glycol, and neopentyl glycol and other glycols
such as hydrogenated Bisphenol ~p cyclohexane dimethanol, caprolactone
dlol (for example the reaction product of caprolactone and ethylene glycol),
hydroxyalkylated bisphenols, and polyether glycols such as poly(oxytetramethy-
lene) glycol and the like~ In addition~ many other diols of various types
can be utilized.
Triols which are pre~erabl~ employed in maki~g the polyester polyols
lnclude compounds such as t~imethylolpropane, trimethylolethane, 1,2,2-propane-
triol, 1,2,4-butanetriol, polycaprolactone triols and triols based on adducts
of propylene oxide and glycerine.
Polycarboxylic acids which may~be e~ployed in making the polyester
polyol consist primarily of monomeric carbo~ylic acids or anhydrides having
2 to 14 carbon atoms per molecule. A~ong the acids ~hich are useful are
phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic
acid, hexahydrophthalic acid, adip~c acid, sebacic acid, maleic acid,
glutarlc acid, chlorendic acid, tetrachlorophthalic acid, and other dicarboxylic
acids of varying types~ , ~
The pol~ester may I~c~ude ~inor amounts of monobasic acids, such
; ~s benæoic acid, and thexe ~a~ ~lso be employed herein polycarboxylic acids
such as trimellitic acid and tricarballyl~c acid (where acids are referred to
above, it is understood that t~e anhydrides of those acids which form anhy-
,
: ,, . ' ' '. . ' ' ,. ' ~ ................................. :
: . . - :
~7~232
drides can be used in place o~ the acid2~ It is preferred that the
polyester include an aliphatic dicarboxylic acid as at least part of the
acid component. It should be noted that if both tricarboxylic acids and
triols are used in the same pol~ester, care must be exercised else
gelation will occur and the pol~ester will be so highly crosslinked that
it will not be water soluble or water dispersible. In general, high
contents o~ triols rather than the tricarbox~lic acids are favored~
The polyester polyols useful herein also include polyester amide
polyols, and polyhydric compounds h~ving polyester structures but not formed
from the reaction o~ a polyol and a polycarboxylic acid, Examples o~ this
latter type includes the so-called lactone polyesters, such as the poly-
caprolactone polyols described in U.S~ Patent 3,169,945 to Hostettler et al.
~ he polyether or polyester polyols used in the water~based coating
compositions of this invention provide a number of advantages thereto. First,
these polyols participate ~ the curlng oE the compositions by being cross~ -
linked through their hydroxyl functionality~ Therefore, these polyols are
incorporated into the film ormed by curing the composition. ~ore impor~antly,
the use of these polyols in the compositions of the invention produces water-
based coatings in which sol~ent and water~popping and sagging are eliminated
or substantially red~lced~ This is of great importance since solvent and
water-popping and sagging have been serious problems with water-based coatings
prior to the instant invention~
The amounts of these polyet~er or polyester polyols ~hich are
ordlnarily included in the binder of the comyositions of the lnvention
vary considerably depending upon the thickness o~ the coating desired,
humidity conditlons and the llke~ ~n general~ from about 5 percent to
about 50 percent by ~eigh~ o$ t~e pol701 based upon total binder solids
may be included wIth a pFe~erred amount being from lO percent to 25 percent~
- 12
:' ' ' ' . ' ' ' ' '
. ~ .
2232
(C? The Water-Soluble or ~ater-Dis~e~_ ble Aldehyde Condensation
Resin Component
As indicated hexeto~o~e, the properties of coatings ~ormed ~rom
the compositions can be ~urther enhanced i~ desired by incorporating a water-
soluble or water-dispersible aldehyde condensation ~esin into the organic
binder.
~ ater-soluble or dlspersible aldehyde condensation resins
which may be employed include the water-soluble or dispersible condensation
products of an aldehyde, pa~ticularly ~ormaldehyde, with an alnino- or
amido- group containing compounds such as urea, melamine, benzoguana~ine
and the like, including the transethers thereof ~ith methanol, butanol
or other lower alcohol (i.e.~ aminoplast resins) are water-soluble or
dispersible condensation products of an aldehyde ~ith a phenolic resin.
Illustrative of water~soluble ox dispersible aminoplast resins
which may be employed are al~y~là~ed melamine ~ormaldehydes such as
methylated melamine formaldehyde, butyla~.ed melamine formaldehyde and
the like; alkylated urea formaldehydes such as methylated urea formaldehyde,
butylated urea ~ormaldehyde and the llke; urea formaldehyde; benzoguanamine
formaldehyde; hexa(methoxymethyl)melamine; hexakis(methoxymethyl)melamine
and similar compounds. 0~ these compounds, hexa(methoxymethyl)melamine
is the preferred compound~
Uhile the aldehyde employed in ~orming the water-soluble or
dispersible aminoplast resin is most ofeen fonnaldehyde, other similar
condensatlon products can be ~ade from other aldehydes or mixtures ~hereof,
such as acetaldehyde, cro~onaldeh~de, acrolein~ benzaldehyde, furfural,
g~yaxal and the li~e.
~ s indicated~ th~ w~te~ solub~e or dispersible aldehyde con~
densatlon resin may~also be a water soluble or dispersiU e phenolic resin
(i.e., phenol-aldehyde res~n~ As ~n the case of the aminoplast resins, the
.' ' .
. ~ .
.~ ~
~ ~ 13 ~
.. . . . . ..
.
~7;2Z;~;~
most commonly used aldehyde is formaldehyde9 although other aldehydes, such
as acetaldehyde, can also be employed~ ~ethylene-releasing and aldehyde
releasing agents, such as paraformaldehyde and hexamethylene tetramine, can
arso be utili~ed as the aldehyde if desix~d~ Vaxious phenols can be used;
for instance, the phenol emplo~ed can be phenol per se, a cresol, or
a substituted phenol in which a hydrocarbon radical having either a
straight chain, a branched chain or a cyclic structure is substituted
for a hydrogen in the aromatic ring. M~xtures of phenols are also often
employed Some specific examples o~ phenols utilized to produce these
resins include p-phenylphenol, p-tert~butylphenol, p-tert-amylphenol~ -
cyclopentylphenol and unsaturated hydrocarbon-substituted phenols such as
the ~onobutenyl phenols containing a butenyl group in the ortho, meta
or para position, and where the~double bond occurs in various positions
in the hydrocarbon chain~ Illustrative o~ such compounds are the well
know~ non-gelled alkaline conden$a~es o~ ~phenol with ~xcess formaldehyde
kno~n as t~` stage resole~
While water-soluble or dispersible phenol aldehyde resins of
the type mentioned above inay be employed àn the invention, the preferred
phenolic res~ns for use in the binder of the compositions of the invention
are ~he methylolphenol ethers of the structure: ~
~ I H20H)n
when n is an integer o~ ~om 1 to 3 a~nd R ~s an unsaturated aliphat~c
group or a halogen~substi~ted aliphatic group~ The groups represented
by R should contain at least 3 caDP~n a~o~s and can be ally~l groups (~hich
are pre~erred~ or others suc~ as ~ethaliy~l, c~ot~ll buteny~l and the like~
~he halogen~substituted unsaturated groups represented b~ ~ can he various
mono- and poly~halogenated de~i~ati~es o~ the above unsaturated aliphatic
groups, for example, 2-chloro-allyl, 3-chloro~allyl, 3~chloro-2 methallyl,
- 14 -
:. :
~(~7ZZ3~2
l-chloro-2-butenyl and corresponding groups containing halogens such as
bromine or ~luorine~
The methylol phenol et~exs which ~ay be employed herein are
described in U.S~ Patent ~o~ 2~597p330 and~, as described therein, can be
produced from sodium or barium salts o~ 2,4,6-tris(hydroxymethyl)phenols
which are ob~ained by reacting formaldehyde with phenol in the presence
of sodium or barium hydroxide. Several methylol phenol ether compositions
o~ th~s type are commercially available and these generally comprise mixtures
of allyl e~hers of mono~, di~ and trimethylol phenols (substituted in the
ortho, para and meta positionsS~ The trimeth~lolated derivative is generally
the predominant component o~ the composition. Such commercially available
methylol e~her compositions are especially preferred for use in the invention~
Whlle any of the above~described aldehyde condensation resins can
be utilized singly in the compositions o~ the invention, it is often advan-
tageous in obtaining desired ph~sical and chemical properties to employ -
mixtures of such resins~ Thus, for example, th~ utilization in the coating
compositi.on of a mixture.of water-soluble or dispersible aldehyde condensation
resins comprising an aminoplast.resin and a methylol phenol ether of the type
described above signieicantl~ improves the detergent resistance of a film
formed from the coating compositlon~ ~
Water~soluble or d~spe~sible aldehyde condensation resins may when
desired.b~ included in the organic binder of the composition of the invention
in amounts ranging from 5 percent to about 40.percent, pre~erably 5 to 20
percent by weight based on total binder solids~
In addition to th~ thermosetting film~forming organic binder
and the aqueous medium~ the water~based coatlng composi~ions of this
lnvention may conta:in v~rious additi~e~ commonly utilized in the coa~ings
7;~3;~
industry. Thus, these compositions may contain conventional pigments
such as tltanium dioxide~ aluminum, silica, lead silica chromate~ carbon
black, talc, barium sulfate and the like~ Colored pigments such as
cadmium red, cadmium yellow? phthalocyanîne blue, phthalocyanine green,
chrome green~ toluidine red~ h~drated iron oxide, and the like may be
included if desired~ ~lso, other adJuvants may be incorporated, such as
dispersing agents, surface-acti~e agents, adhesion promoting agents, melting
agents, flow agentsl antioxidants~ and the like.
The water-based coating compositions o~ the invention can be
applied by me~hods conventionally employed in the coatings industry, such
as brushing, dlpping~ flow coating, roll coating, spraying and the like.
After application, the compositions are ordinarily dried and
cuxed by baking at ele~ated temperatures to produce a hard, thermoset film.
~he precise baking schedule ~ill depend upon the particular composition
utilized~ the nature o~ ~he substrate~ thickness of the coating and the
like. However? it should be observed t~t the baking temperature employed
must not be so high to ~ol~tilize the polyol component be~ore it can
be crosslinked into the ~ilm~ Thus, the baking temperature usually should
not exceed about 500F~ unless ~or very short periods~ ~he normal curing
time may convenien~ly range from 5 to 45 minutes for usual industrial
situations. In coil coating applications, baking schedules of short times
and high temperatures can be used~
The water-based coat~ng compositions o~ the invention may have
solids contents ranging from 25 to 70 percent b~ weight~ Solids include
the interpolymer; polyol, aldehyde condensation resin when employed and any
desired pigmentation~
~ 16 _
~6~72Z32
The following examples set forth specific embodiments o~ the
instant invention~ Howe~e~, ~he inventlon is not to be co~strued as being
limited to these embod~nents ~or there are, of course, numerous possible
variations and modificatlons~ All parts and percentages in the Exa~ples
as well as throughout the speci~ication are by weight unless otherwise
indicated.
.
~XA~PL~ A
~his exa~ple illustrates the preparation of an aqueous dis-
persion o an amlde type interpolymer employed in the compositions o~
this invention~ ~
~o a reactor e~uipped with re~lux condenser, heating means,
stirrer, thermometer and nitrogen inlet were charged 130~0 grams of
A ethylene glycol monoeth~l ether Chereina~ter eth~l Cellosolve3 and 325~0
gra~s of a feed mixture cons~sting o~ 58~6 percent styrene, 15.0 percent
meth~l methacrylate~ 6~7 percent acr~lic acid, 19 7 percent N~(butoxy-
~ethyl)acrylamide and 3~0 percent tertiary dodecyl mercaptan~ The charged
matter was then heated under nitrogen to reflux (about 125C.). ~fte~.
reflux had begun, an additional 1063.0 grams of the above ~eed mixture
and 12~0 grams of alpha, alpha~-azobisCisobutyronitrile3 were added to
the reactor over a period of 3 hours~ Following this addition~ a total
~: oP 5.1 grams of tertiar~ butyl perbenzoate and 22.5 grams of ethyl Cello-
sol~e were added to the reactor in 3 e~ual increments (i.e~, 1 7 grams
oP.tertlar~ butyl perbenzoate and 7~5 g~a~s o~ ethyl Cellosolve) over
: a period o~ about 5 hours with.the ~ir~ two increments being added at
1~5 hour intervals~ At ~h~ end o~ ~his pe~iod, the reactor ~as cooled ~ ;
.
. 17
.. .. ..
.. . . . . . . . . . .
~i7;~232
to room temperature~ After approximately one hour~ the reaction mixture
was heated to approximately 96PC. and 39.9 grams of dimethylethanolamine
was added to the re~ctor~ A~ter ~his addition, heating was continued
until a temperature of 108C~ was attRine~ and then 12sO grams of one
percent Triton X-100 a non~ionic7 alk~rylethoxyethanol sur~actant, was
added to the reactor~ ~ollo~ng the addition of the surfactant? 1845.0
grams of deionized water ~as added to the reaction m-ixture. `
The resultant amide interpoly~er dispersion had a total solids
content of 34.7 perce~t, an acid val~e o~ 15~7 and a viscosity of 1850
centipoises~ The aqueous medium consi~ted of 86~3 percent water and 13.7
percent organic solvents
EXA~PLE B
This example illustrates an alternat~ve procedure for preparing
an aqueous dispersion of amide type interpolymer in which a polyether
~olyol component is utilized as a portion of the polymeri~ation medium.
To a reactor e~uipped with ref-l~x condenser, heating means,
stirrer, thermometer and nitrogen lnlet was charged 300~9 gra~s of a 100
percent solids sucrose polyether polyol (formed by reacting l.O mole of
sucrose and 20,5 moles of propylene oxide) ha~ing a viscosity of about
6,500 centipoises and an OH value of 325; 137.3 grams of diethylene glycol
monomethyl ether Chereinafter DEG~E~; 345 00 grams of a feed mixture
(hereinafter referred to fo~ convenlence RS ~eed A~') containing, on a
monomer solids basis, 58,6 percent styrene~ 15.0 percent methyl methacry~
late, 6~7 percent acrylic ac~d, 19~7 percent ~(butoxymethyl)acryla~ide?
3~0 percent tert~ary~dodec~l ~ercàptan and 1~0 percent alpha~ alpha~
azobis(lsobutyronitr~le~i and 6~Q gra~s o~ a ~eed mixture ~hereinafter
.
~ 7~a~i/~ ~rk
~ 18 _
~972~:32
referred to for convenience as ~eed B~t~ containing 25 percent 2-acryl-
amido~2-methyl propane sulfonic acld, 62.5 percent deionized water, and
12~5 percen~ dimetbylethanola~ine~ The mixture was heated under nitro-
gen to about 105C., at which time an exotherm was observed. Heating
and nitrogen flow were then suspanded during the period of exotherm
After conclusion of the exot~erm, heating under nitrogen was resumed
and the mixture was heated to about 130C. ~t this point, an additional
1049~0 grams of feed A and 18~0 grams of feed B were added to the reactor
over a period of about 3 hours~ ~hen this addition was completed, a total
of 5.1 grams of tertiary butyl perbenzoate and l5~0 grams of DEGMME were
added to the reactor in 3 equal increments ~i.e~ 7 grams of tertiary
butyl perbenzoate and 5.0 grams of DEGMME) over a period of about 5 hours
with the first and second increments being added at 1~5 hour intervals.
Following this addition 46.Q grams o~ dimethylethanolamine were added
to the reactor. Then the reaction ~ixture was cooled to 75VC. and 2442
grams of deionized water were added to the reactor. The reaction product
was then cooled and filtered.
The resultant amide interpolymer-sucrose polyether polyol
dispersion had a total sollds content o~ 34,1 percent, a viscosi~y of
1860 centipoises and an acid value of 13~ The aqueous medium consisted of
87.6 percent water and 12~6 percent organic solyents~
-.
EXA~PLES 1~2
These examples illustrate the e~fect of the pol~ol com~
ponent on the water-popping and solvent popping characteristics of water-based
coating compositions. ~n ~hese examples a control coating composition
(Example 1~ was ~irst for~lated ~rom the Inte~polymer dispersion o ~xample A.
Then a test composition was prepared by~adding a polyether pol~ol to a sample
of the control composltion~
,
.. . . .. . . . . . .
!- ... , : . : : , :. - . : . . . . : . ~
'1~7ZZ3~
The cont~ol and test compositions were prepared utilizing
standard paint mixing techni~ues. Composition formulations and
properties were as follows;
.
: Ra~ts by Weight
Example No. 1 Example No. 2
(Control)
Ingredients
~nterpolymer dispersion of ~xample.~ 146~5 109~0
Pigment Paste (a) 113.0 113.0
Sucrose polyether polyol (b~ 37.5
Total 259~5 259.5
In~erpolymer/polyol binder ~atio 100/0 50/50
Total solids (percent) ~ . 56~5 56.5
Viscosity (seconds) #4 Ford C~p 18 18 -
( ~A pigment paste consisting of 66~7 percent titanium
dioxide, 25~9 percent water~ 1.8 percent ethylene
glycol, 3.2 percent Triton X~].00 alkarylethoxyethanol
surfactant, 0.3 percent NOPCO 3MY, an antifoaming
agent available from Nopco Chemical Company and 0.1
~ ~ercent Tamol 731, a pigment wetting agent available
: ~rom Rohm & Haas Company~
(b~A 100 percent soIids sucrose polyether polyol,
having a viscosit~ of 6500 centipoises and a
: : hydroxyl value of 325, formed by-reacting 1.0
mole of sucrose with 20,5 moles of propylene
: : oxide~
'
~ he above compositlons were evaluated for sagging characteristlcs
by sprar appl~.ing samples t~e~eof onto.~e~ical steel panels at a film
: ~hickness of 1.2 mils~ In evaluatlng the compositions utilizing this
test,:the control compoistion, Example 1, sagged badly, virtuallY
running off the panel w~ereas th~.~est composi~ion~ Example 2~.showed
nQ ~ag8ing ~
~ ~a~k
~ 20 -.
~637;2Z3Z
~XA~RLES 3~5
These examples illustrate the effect of the polyol and
aldehyde condensation resln co~ponents on the water-popping and solvent
popping characteristics o~ water-based coating compositions. In these
examples a control coating composition (Example 3) was first formulated
~rom the interpolymer dispersion o Example A. Then test compositions
were prepared by adding a polyether polyol and an aldehyde condensation
resin (in these examples an a~inoplast resin~ to samples o~ the control
composition.
The control and test compoai~ions were prepared utilizing
standard palnt mixing techni~ues~ Composition formulations and proper-
ties were as follows:
Parts by ~ei~h~t
- ~ X A M P L~E~ N 0.
3 4 5
(Control)
Ingredients
Interpolymer dispersion
of Example A 146~5 97~4 86.5
Pigment paste (a) 113~0 113.0 113.0
Sucrose polyether polyol (b~ 33.8 30.0
Hexa(methoxymethyl)melamine --- 7.5 15~0
; Total 259.5 251.7 244.5
Interpolymer/polyol/amino~ -
plast binder ratio100[QlO 45/45/10 40/40/20
Total solids (percent) 56~5 58,0 59.5
Viscosity (seconds~
#4 Ford Cup 18 19 20
; (a)A pigment paste consisting of 66~7 percent titanium dioxide,
25.9 percent wate~ 3~8 pe~cent ethylene glycol, 3~2 percent
Triton~X~00 alk~la~lethoxye~hanol surfactant~ 0.3 percent
NOPCO 3MY,~an antifoa~ing agent a~ailable from ~opco Chemical
Company and 0.1 percent Tamol~731, a pigmen~ wetting agent
a~ailable from ~o~m ~ Haas Company.
~ 21 -
.. . ~ . . . . . .
., , , ' .
~ 7Z232
( ~A 100 percent solids sucrose polyether polyol having a
viscosity of 6500 centipoises and a hydroxyl value of
325 formed by reacting 1~0 ~ole of sucrose with 20.5 moles
of propylene oxide~
The above compositions were eyaluated for sagging character- -
istics by spray applying sa~ples thereof onto vertical steel panels at
a film thickness of 1~2 mils~ ~n evaluating the compositions utilizing
this test, the control composition ci~e.~ Example 3) sagged badly, vir-
tually running of the panel whereas the test compositions (i.e., Examples
4~5) showed no sagging~ -
The compositions ~ere evaluated for solvent or water popping
by spray applying at 8~F~ and 50 percent relati~e humidity samples of
the compositions on steel panels~ allowing a 5 minute flash period and
then baking the panels in an o~en ~or 10 minutes at 300F~ Popping
char~cteristics were measured by determinlng the dry film thickness
which could be obtained without popping~ Using this test, the control
composition Ci~e., Example 3) could.be sprayed to obtain a dry film
thickness of 1.6 mils before popping was observed while the test compo-
sitions could be sprayed ~o obtain a dry ~ilm thickness of 2.2 mils
without popping.
: This example illustrates the effect of the polyether polyol
: and aldehyde condensation ~e~in component on solvent popping and other
properties of a coating compositlon ~ormulated from the interpolymer~polyether
; polyol dispersion of Exa~pl~ B~ The composition was prepared by blending
the interpoly~er~polyethe~ pol~ol d~spers~on of Example B with an aldehyde
condensation resin and other deslxed addit~es utlli~ing conventional
paint mixing procedure~ The composi`tion h~d the following formulation
and properties:
- 22
~L~7~3Z
In~redients Parts by Weight
Interpolymex dispersion o~ ~xa~ple B 425.40
Pigment paste (a~ 570.10
Sucrose Polyether polyol of Examples 4~5 56~70
He~a~methoxymethyl)melamine 28.40
Total 1080~60
Interpolymer/polyol/am1noplas~ binder ratio 70/20/lO
Total solids (%) 52~4
Spray viscosity (seconds) ~ #4 ~ord Cup 20
The above composit~on was spray applied to steel panels and
cured 20 minutes at 325F. The resultant film was evaluated ~or various
properties with results shown in the Table~
T ~ B L E
.
Pencil Hardness 411-5H
Impace (in lb~) ~
Direct 50
Reverse lO
Initlal Gloss
20 23
60 79
R~ T~ Water Immersion (Hours2 500
. . .
Humidity Resistance~(120~ 500
: Salt spray 5% NaCl (Hour6~ . ' 336
Solvent or Water Popping ~ 5 mlnute ~lash
(Dr~ ~ilm thickness ~thout pop~ing). . ~3 mils
.~ ,
,
,;
~ 23
:, , , . . . . : .
: , . .
~L~7~23Z
As the above exa~ples illustrate, the incorporation of the
polyol and aldehyde condensation resin components in the binder of the
compositions of the invention dramatlcally improves resistance to water-
popping, solvent-popping, and sagging permïtting the application of thicker
films and also provides films having excellent water, humidity, and salt
spray resistance.
Similar results to those shown in the examples may be obtained
by using other interpolymers of the type described in the specification
in place of those utilized in the examples~ Thus? for example, an inter-
polymer derived from N~(butoxymeth~l~meth~cr~lamide, methacrylic acid,
acrylonltrile, butyl methacrylate, and ethyl acrylate may be utilized.
~dditionally, various other ~ater-soluble or water-dispersible polyether
or polyester polyols of the type described may be substituted for the
sucrose polyether polyol utilized in the examples. For example, a poly~
caprolactone polyol having a moleculaF weight of about 530 formed by
reacting 1~0 moles of diethylene glycol with 3~7 moles of epsilon-capro~
lactone may be employed. Further, various other aldehyde condensation
resins and mixtures of such reslns of the type described may be substituted
for the hexa(methoxymethyl)melamine utilized ln the examples. For example
a mixture of a methylolated melamine formaldehyde resin and a methylol
phenol ether may be utllized.
According to the provisions o~ the patent statute~ there are
described above the invention and what ~e noW considered to be its best
embodime~ts~ Howevex, it is to ~e unders~ood that wi~hin the scope of
the appended claims the invent~on may~be p~acticed othe~wise th~n
specifically described~
~ 24
.
