Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
Water-containing polymeric product~ ~uch as
waterborne paint~, ~talns, adhe~lves, prlntlng lnks and
coatlngs ~lnd lncreaslng utlllty because Or thelr
~qarety, economy and ease of applicatlon. However, the
drying characterlqtlcq of ~uch products are varlable
and cannot be easlly controlled, because they are
baslcally llmlted to the evaporation characterlstlc3 o~
water. Thu , the drying behavior of aqusous polymer
products ls hi~hly ~ependent on the conditions of
temperature, humidlty and alr velocity. For example,
coatlng ~ilms o~ such products can dry practlcally
lnstantaneously under hot, dry, wlndy condltions
leadln~ to poor lappln~ characterlstic~. F~urther, such
~0 drylng condl~lons tend to ~palr thé quallty of fllm
~ormatlon, penetratlon o~ and adhe~ion to the
sub~trate.
Polymeric composltlon borne ln organio solvents
are dlfferent from the waterborne product~, in that
solvent~ or solvent blends wlth a wlde range Or boiling
polnt~ and volatlllty can be used to control the drying
characterl~tlcs accordlng to appllcation
requlrementq. For example, consumer paint~ employing
alkyd re in3 are made wlth hydrocarbon ~olvents o~
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volatility selected such that the drying rate is
sufflcient to allow setting of the film to minlmize
sagging, running, and dust pickup, yet which permits
good "melting in" of paint at overlapping brush or
roller strokes. The disadvantages of such organic
solvent based compositions are the difficulties of
clean-up, the toxic nature of organic solvents,
environmental pollution, and the relatively high cost
of organic solvents which are ultimately wasted.
The conventional practice ln solving the drying
rate problems of water-based compositions is to add
substantial levels of water soluble solvents to such
systems to increase the wet-edge or open time. These
techniques are dlscussed by M. D~ Andrews, "Influence
of Ethylene and Propylene Glycols on Drylng
Characteristics of Latex Palnt~," Journal of Paint
Technology, vol. 46, page 40 (1974); D. A. Sullivan,
"Water and Solvent Evaporation from Latex and Latex
Paint Films," Journal of Paint Technology, vol. 479
~0 page 60 (1975); and C. R. Martens, Waterborne Coatings,
Van Nostrand Reinhold, page 153 (1981). These
references disclose the use of short chain water-
soluble alcohols and glycols as cosolvents for water-
based coatlngs to improve freeze-thaw stability, ald
~5 coalescence of the latex partlcles, improve leveling,
etc., in addition to prolonging wet-edge or open
tlme. To obtain significant lmprovement in wet-edge or
open time, hl~h levels of these low molecular weight
cosolvents are required, often 10 to 20 percent or more
3~ based on total volatile content, since they are
belleved to function slmply by belng completely soluble
ln water; thus reduclng the vapor pressure of water.
These cosolvents exhlblt low surface actlvity, and the
use of high levels tend to negate the intrinslc
advantages of the water-based composltions.
The use of evaporation retarders on the surface of
2 2~379
reservoirs to control water evaporatlon i~ known in the
art. The evaporation retarders are typlcally aliphatlc
alcohols and ether alcohols containlng 16 to 30
carbon~, ~uch as described ln U.S. Patent No. 3,146,059
and Indlan Patent No. 70,670 The use Or the~e long
chaln alcohols as surface monolayers on water 18
further dlscu~sed by E. R. Noe and R. G. Dressler,
"Per~ormance of Odd and Even-Chain Pure Alcohol
Monolayer~ in W~ter E~aporation Retardatlon," I & EC
Product Research and Development, vol. 6, page 132
(1967) and in other literature. Although these long
chain alcohols and ether alcohol~ have been erfective
on relatlvely pure water due to their surface actlvity,
thelr utility ln multi-component, water-based polymerlc
composltions had not prevlously been recognlzed or
dlscovered.
U.S. Patent No. 2,965,678 dlsclo3es the use of
branched-chaln alcohols a~ wetting agents and
detergent~. However there ls no teachlng or suggestlon
that unbranched-chaln compounds are effectlve for water
evaporatlon retardation ln aqueous polymer
composltlons.
U.S. Patent No. 3,287,300 teaches the use of
allphatic carboxylic aeids ln polyvlnyl ester emulslons
to lower the coalescence temperature. The '300 patent
teaches nothlng about evaporatlon suppresslon and the
lmportance of uslng C16-C24 allphatic straight-chain
compounds to reduce water evaporatlon from polymer
composltlon~.
U.S. Patent No. 3~3~23 di~close~ cleanlng and
pollshln~ ~omp~u~ds w~ic~ are e~ul~on~ of natural and
synthetlc waxes and resins, and whlch contaln very
large quantitles (l.e. 40-50%) o~ volatlle organlc
solvent. Moreover, the emulsiflers disclosed ln the
'123 patent would not be effective as evaporatlon
suppressants because they are rererred to as belng
75~
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highly branched, havlng a relatlvely low number of
carbon atom (i.e. 12-1~), or havlng a high number o~
oxyethylene unlts.
U.S. Patent No. 3,847,855 di~closes a latex
polymerlzation proce~ which uses a volatlle surfactant
for the polymerlzatlon. The '855 patent teaches
nothing about evaporatlon suppres~ion, and there iR no
teaching or suggestlon that any of the dlverse
surfacta~ mentioned would be effective ln retarding
evaporation o~ water~ ~at~er, the ~ugltive surfactants
descrlbed ln the '855 patent are u~éd a~ an lngredlent
durlng the polymerlzation proce~s.
U.S. Patent No. 3,988,275 dlsclose~ a
polymerizatlon proces~ for maklng concentrated latex of
synthetic rubbers uslng emul~i~ying agent~ ~uch as
fatty acids. Methods to achleve ~uppresslon of
evaporatlon rate of water from the latex rormulatlons
are not taught or lmplied. The emulsi~lers dlsclosed
ln the '275 patent are generally not suitable for
evaporation suppres~lon because they are generally too
asymmetrical~and of relatlvely Ahort chaln length.
U.S. Patent NoO 4,131,585 dlsclo~e~ pla~tlcizer-
type levellng agents for floor poll~h emulslon~. The
levellng agents are requlred to contaln elther non-
llnear alkyl or alkyl~en$ene hydrocarbon group~, and
would therefore not be ~uitable evapor~tlon
~uppressant~ be~au~e they do not form compact ~urPace
film~ to ~etard wa~e~ evaporation. Moreo~er, they are
required to contaln 15 ~ les~ carbon atom~ ln the
alkyl chaln. The '585 patent speclflcally teaches
agalnst the ~Re of llnear alcohol derlvatlve~.
UOS. Patent No. 4,330,338 dl~clo~es emulslon~ ln
water of reslns dlssolved in organlc Rolvent for u~e a~
pharmaceutlcal coating composltlon~. The '338 patent
teaches ~r suggests nothlng regarding the selection of
surfactants except ~hat they are to assi~t ln produclng
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a qtable emulsion. Nothlng ls taught or ~ugge~ted
concernlng thelr sur~ace actlvlty or effect on water
evaporation. The fatty alcohol ethoxylates disclo~ed
as emulslfiers have only lauryl (12 carbon atoms)
hydrophobes, and generally have too ex¢es~lve a degree
of ethoxylatinn for use as efrective evaporatlon
~uppressants.
U.S. Patent No. 4,454,26~ discloses suspen~ions of
water-soluble polymer~ ln organic solvent and the use
o~ surfactant~q therefor. Such materlalQ are then later
dissolved ln water to make a polymer solutlon for oil
recovery fro~ well~. The '260 patent ls tot~lly
unrelated to the u~e Or long stralght-chain allphatic
compound~ for reductlon ln evaporation rate of water
from waterborne polymer composltlons. Rather the '260
patent teache~ the use of alkali or alkallne-earth
metal salt~ of fatty acids as thlckeners for the
suspenslons of water-soluble polymers ln organlc
~olvent.
2~ Appllcants have ~urprl~lngly dlscovered that low
levels o~ surface actlve, long chaln, aliphatlc
hydrocarbon-type compounds can be used to control and
improve the drylng characterlstlcs of aqueous-ba~ed
polymer composltlons. These long chaln aliphatlc
2~ compounds sre effectlve a~ evaporatlon suppre~slng
agents at leYe~s as low as 1% by weigh~ or less. Their
ef~ectlveness ls belleved to be attributed to their
abillty t~ become hlgh~ aon~entrated and compactly
ordered at the alr/~a~er in~errace~ ~Yen when lnltlally
uniformly mlxed lnto the aqueous-based polymer
compositlons.
It 1~ the obJect o~ thls lnventlon to provlde a
method ~or reducing the evaporatlon rate o~ water rrom
aqueous polymer compo~itlons u~ing low levels of
~ur~ace active, long chaln, unbranched allphatlc
compound~. It i~ also an obJect of this lnventlon to
6 --
37
extend the wet-edge or open time of aqueous-based
coatings and the like when applied to a substrate. It
is a further ob~ect of the lnvention to reduce skinning
of waterborne polymer compositions in contalners, and
to retard drying out on application equipment such as
rollers and brushes. It is an even further ob~ect of
the present invention to improve the quality of film
formation/adhesion of aqueous polymerlc coatings by
incorporating therein low levels of surface active
evaporation suppressants.
SUMMARY OF THE INVENTION
This invention relates to a method for reducing
the rate of evaporation of water from waterborne
polymer products, by incorporating therein low levels
of surface-active allphatic C16 or greater hydrocarbon-
type compounds. The invention also relates to aqueous
polymer compositions containlng these Cl6 or greater
surface-active evaporation suppressants. Useful
surface-active, aliphatic evaporatlon-suppressing
agents for the invention include hydrocarbon-type
compounds consi~ting of a saturated, unbranched carbon-
carbon chain length of about 16 atoms or greater and
contalnlng one or more hydrophilic groups. The
evaporation ~uppressing agents can be unlformly
~S incorporated into aqueou~ polymer compositions
preferably at levels of about 1% or less by weight.
The evaporation ~uppressant~ preferably include the
long, straight-chain alcohol~, ether alcohols, and
salt~ of carboxylic acids.
~he evaporatlon suppressant are effective in
extending the wet-edge or open time of waterborne
polymer coatings to allow good meldlng or melting-in of
the coating at overlapplng brush or roller strokes.
The evaporation suppressant are also ef~ective in
retarding skinnlng of waterborne polymer~ in
containers, reducing drying out on application
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equipment, and improving quality of film
formation/adhesion.
DETAILED DESCRIPTION
This invention involves a novel method for
reducing the evaporation rate of water from waterborne
polymer products, and involves novel aqueous polymer
compositions containing low levels of surface-active,
aliphatic C16 or greater evaporation-suppress~ng
agents. The use of low concentrations of these long-
chain aliphatlc evaporation suppressants in waterborne
polymerlc products, such as latex coatlng, increases
the wet-edge or open time of the coating, improves film
~ormation/adhesion, and reduces skinning.
The evaporation suppressing agents useful in
practicing this inventlon include sur~ace-active
aliphatic compounds havlng a saturated, unbranched
carbon-carbon chain length of about 16 atoms or
greater, and containing one or more hydrophillc
groups. Particularly useful evaporation suppressants
include, for example, stralght chain alcohols, ether
alcohols, carboxylic acids and salts thereof. The
evaporation suppressants have the structural formulae:
CH3(aH2)m(OcH2lH)n[o~cH2)y]zoH or
~5 CH3(CH2)m_lCOOR or
CH3(cH2)mocH2cH(oH)cH2oH
whereln m is an lnteger from about 15 to about 25; n is
an integer from 0 to about 3; y is an integer from 1 to
about 4; z ls an integer ~rom 0 to about 3; X i8 -H or
-CH3; R is -H, -NH4, amine or alkali metal salt; and
the sum of n and z does not exceed 3. Preferably m ls
18 to 24, n ls 0 to 2, y is 2 to 4, z is 0 to 2, R is
amlne or alkali metal salt, and the sum of n and z does
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not exceed 2. More preferably i) m is 20 to 24, n 1S
O, y is 2 or 3, and æ i9 0 or 1, or ii) n i8 1 or 2
and z is 0. Most preferably n i8 O, y iS 2, and z is O
or 1. The evaporation suppressants preferably contain
hydrophilic groups selected from -OH, salts of -COOH,
-OCH2~H(OH)CH20H, and -(OCH2CH)n[O(CH2)y]zOH
wherein X, n, y and z are as defined above. Other
diver3e hydrophilic groups are believed to be suitable
l for this invention, such as, for example, sulfates,
sulfonates, amines, amine oxides, amides, phosphates,
and phosphonates.
Some examples of suitable evaporation suppressants
for practlcing this invention are hexadecanol,
heptadecanol, octadecanol, nonadecanol, eicosanol and
related ether alcohols and carboxylic acids. The most
preferred evaporation suppressant for use ln this
invention is l-eicosanol CCH3(CH2)18CH2OH].
The evaporation suppressants are preferably
2~ uniformly incorporated into the waterborne polymer
compositions. They can be added to the compositlon by
a variety Or methods, such as, as a dilute solution in
organic solvent, as a fine powder, as a molten liquid,
and as an emulsion in water. The evaporation
suppressants may be mixed or blended into the polymer
compositions using any techniques known in the art. To
be useful for this invention, the evaporation
suppressants themselves must be solid at standard
conditions, although they may be added as a solution or
molten liquld as mentioned above.
The lnventlon is practiced using relatively low
levels of the evaporation suppressants ln the polymeric
compositions. Thls allows control of drylng
characteristics, as with solvent-based systems, but
retains all the advantages of aqueous based
compositlons. The specific concentration of
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evaporatlon suppresAant3 wlll depend on the specl~lc
compound u~ed, the Apeciflc polymerlc ~ormulatlon, and
appllcatlon needs. Effectlve concentratlons o~
evaporatlon suppressant are generally les~ than 5% by
welght based on the total wel~ht of the polymer
composltions, and preferably the concentration is about
1% by weight or less. Either one or a mlxture of
evaporatlon suppre~sants may be used in carrying out
the lnventlon.
A pre~eP~ed embodlment is to add the evaporatlon
suppressant~ to the aqueous polymerlc compositions as a
pre-emulsion in water. More preferably the pre-
emulslon of ~uppres~ants ln water contaln~ an
auxiliary surfactant to ald ln stabllizlng the
emulsion. It is lmportant to select an emul~lfler
which does not lnterfere with the sur~ace barrier
properties or surface actlvlty of the ~uppressants;
wlth ~alts o~ aliphatic long chaln carboxyllc aclds
belng pre~erred. The evaporatlon suppressant~ may also
be added as a ~olutlon in a suitable organlc solvent.
The effectlveness of the evaporatlon suppres~ants
in aqueous polymer composltlonA ls believed to be
attributed to thelr abillty to form hlghly compact and
dense monolayers at ~he alr/water lnterface. It ls
~5 speculated that th~ hydrocarbon portlon o~ the molecule
1~ orlented toward the air, w~ile ~he ~ydrophilic
groups are ~n khe surf~ce reglon Or the water.
Surprisingly, the e~p~ratlon suppres~ants can exhlblt
good Rurface activlty even ln the presence of the
multiple components and other competing surface actlve
lngredlents ln the polymer composltlons, and even when
unlformly mlxed thereln. The evaporation suppressant~
that are useful ln forming the arorementloned compact
and dense monolayers appear to be those that are solld~
by them~elves at ~tandard conditions.
The evaporatlon suppressants are useful ln
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controlllng the drylng characterlstlcs of a varlety of
aqueous polymer compo~ltions, ~uch as palntsJ ~talns,
varnlshes, coatings, adheslves, an~ ink~. These
aqueous polymer compo~itlons lnclude, for example,
S polymeric latexe~, solutlon polymer~, and colloldal
dlspersion~, ~uch as descrlbed by C0 R. Martens,
Waterborne C~atin~ , Van Nostrand Reinhold, page~ 41-51
(1981). The ~uppressants are p~rtlcularly sultable for
use in acrylic latex type compo~ltions such as
de3cribed in U.S. Patent Nos. 4,129,448; 4,102,843; and
3,736,286. In a preferred embodLment
o~ the lnventlon, the polymerlc composltlon i8 an
aqueous dlspersion of a vlnyl or acryllc emulslon, such
a~ thoqe used in maklng water-based paints, stalns,
adhesive~ and varnishes.
Suitable aqueous polymer compo~ltlons ~or paint~
are aqueous addltlon polymer dlsperslon~, generally
obtained ~ost convenlently by dlrect emul~ion
polymerlzstlon. Also sultable aqueous polymer
compo~itions lnclude aqueous ~olution polymer~,
emulsions of resln ln water, and colloidal
disperslons. The most lmportant of these di~per~ion~
used in ~aking w~te~-ba~ed paints are polymers
including homopolymers and copolymers o~: (l) vlnyl
~5 e~ters of an allphatlc acld havlng l to 18 carbon
ato~s, e~pecl~lLy ~Inyl acetate; (2) acrylic acld
esters and methacryllc acid ~ter~ of an alcohol having
l to 18 carbon atoms, e~peclally methyl acrylate, ethyl
acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl
methacrylate, ethyl methacrylate and butyl
methacrylate; and (3) mono- and dl-ethylenlcally
unsaturated hydrocarbons, quch a~ ethylene,
lsobutylene, styrene, and allphatlc dlenes, such a~
butadl ene9 i 30pr ene, and chloroprene.
Poly(vinyl acetate) and copolymers oP vlnyl
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acetate ~ith one or more of the following monomers;
vlnyl chloride, vinylldene chloride, styrene,
vinyltoluene, acrylonitrile, methacrylonitrile, one or
two o~ the acrylic and methacrylic acid esters
mentioned above are well known a~ the film-forming
component of aqueous-based paints. Similarly
copolymers of one or more of the acrylic or methacrylic
acid esters mentioned above with one or more of the
following monomers: vinyl acetate, vinyl chloride,
vinylidene chloride, ~tyrene, vlnyltoluene,
acrylonitrile, and methacrylonitrile are also more or
less conventlonally employed in aqueous base paints.
Homopolymers of ethylene, i~obutylene, and styrene, and
copolymer~ of one or more of these hydrocarbons with
one or more esters, nitriles or amide~ of acrylic acld
or of methacrylic acid or with vinyl esters, such as
vinyl acetate and vinyl chloride, or with vinylidene
chloride are also used. The dlene polymers are
generally used in aqueous base paints in the form of
2~ copolymer~ with one or more monomers following:
styrene, vinyltolueneg acrylonitrlle,
methacrylonitrile3 and the abovementioned esters of
acryllc acid or methacrylic acid. It is al~o quite
common to include a small amount, such a~ l/2 to 2.5%
~5 or more, of an acid monomer in the monomer mlxture u~ed
for making the copolymers for all three general type~
mentioned above by emul~lon polymerization. Aclds used
include acrylic, methacrylic, itaconlc, aconitic,
citraconic, crotonic, maleic~ fumaric3 the dimer o~
acrylic acid, and so on.
These aqueous dispersions as the emul~ion polymer
in the paint may be made using one or more emulslfier~
of anionic, cationic, or non-ionic type. Mixtures of
two or more emulslfier~ regardles~ of type may be used,
except that it is generally undesirable to mix a
cationic with an anionlc type in any appreciable
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amounts ~ln¢e they tend to neutrallze ea¢h other. The
average particle slze or diameter of the3e dispersed
polymers may be rrom about 0.03 to 3 micron~ or even
larger. ~he partlcle size, whenever referred to
hereln, iq the "welght average dlameter." Thlq number,
expressed ln mlcrons, ¢an be determined by electron
mi¢roscopy. In general~ the molecular welghts Or these
emulAlon polymers are hlgh, e.g., from about 100,000 to
10 milllon vi~cosity average, most commonly above
500,000.
In ~eneral, a gallon o~ emulslon palnt ~s
Gomprl~d o~ about 0.5 to 3 lbs. of film-~ormlng resin
and about 0.2 to about 5 lbs. o~ rlnely-dlvided
pigment. ~yplcal plgment~ are titanium dloxide and
other titanium pigment~, whlte lead, zlnc oxlde, zlnc
sul~ide, barium sul~ate, calclum carbonateJ llthopone,
slllca, talc, mica, clays, lron oxide, carbon black3
cadmlum sulrlde, toluidine red, chrome orange, chrome
yellow, chrome green, and otherq known in the art.
Typlcal latlces o~ ~llm~formlng reslns are those Or the
alkyl acrylates and methacrylates, vlnyl acetate,
styrene-butadlene~ and others known in the art. Mlnor
amount~ of oth~r coatlngs addl~lves may be lnoluded ln
the palnt formulatlons, ~or example, antl-foa~s~
mlldew¢ldes, thlckener~, wetting agents, ba¢terlostats,
etc. ~he present inventlon i~ also useful ln clear
unpigmented latex coatlngs, stains and varnishes.
The ~ollowin~ ~xamples are presented to rurther
illustrate thls lnvention, but are not intended in a
limltative sense.
EXAMP~ES I - VIII
Varlous long chaln aliphatlc hydro¢arbon-type
compounds were evaluated as evaporation ~uppre~sant~ ln
both a latex and a ~ormulated latex coating. The latex
was an aqueous emulslon o~ qynthetic acrylic polymer
havlng a 45% by welght ~ollds content which ls sold by
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Rohm and Haa~ Company a~"Emul~lon E 1630" The
~ormulated latex coatlng was prepared uslng ~he same
a¢rylic emulslon accordlng to the following reclpe:
Amount
In~redient(parts by we lght )
Acryll¢ latex (3-1630) 600
Wettlng agent 2.0
Antlroamer 2.5
Coalescent 40.0
Thickener 24.8
Neutralizing Ba~e 6.4
Water 170.8
25 gram ~amples o~ each Or the unrormulated and
formulat~d latex ~oating were placed ln 9 cm diameter
dlshe~ and to each was added dropwise 1 ~ram o~ a 0,2%
by weight ~olution of various hydrocarbon compounds in
hexane to be tested as evaporatlon retarders. A~ter
rlashln~ of r the hexane, weight 108s rrom eaoh ~ample
due to water evaporation was measured and ¢ompared with
control ~amples contalning no evaporation
s~uppre ~ants. The results are expre~ed as the percent
reductlon in evaporatlon and are presented in Table I.
TABL~ I
% Reduction
~5 in Evaporatlon Rate (25C)
Evaporatlon Fornulated
Sup~ressant tex
Control None 0 0
E~ample I CH3(CH2)1~H 28 13
Example II CH3(CH2)17H 23 13
E~le III CH3(CH2)19OH 72 60
E~le IV CH3(CH2)21H 17
E~le V CH3(CH2)17(0CH2CH2)20H 19 10
E~le Vl CH3~H~)210CH2CH2H 58 30
Example VII Olelc Aald 0
E~le VIII Stearic Acld 17%
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EXAMPLES IX - XI
Addltlonal compounds were evaluated for thelr
effectlvene3s as evaporation ~uppressants followlng the
procedure~ o~ Examples I-VIII above, except that 0.1%
by welght solutlons of the hydrocarbons ln hexane were
u~ed. The re~ults of this evaluation are glven ln
Table II.
~E ~
~ Reductlon
ln Evaporatlon Rate (25C)
EYaporatlon Formulated
SuEp~esaant L~tex L~tex
,
ControlNbne 0 0
CM3(CH2)210CH2cH2cH20H 54 31
Example X CH3(CH2)1~0CN2~(0H)CH~H 25 25
E~le ~CH3(C~2)210CH2CH~OH)CH20H38 25
EXAMPLE XII
l-elco~anol, CH3(CH2)190H, was evaluated as an
evaporatlon suppreqsant when unlformly lncorporated
lnto a clear lat~x ~oatlng, ~o 31~5~ of acryllc latex
(sold by Roh~ and Haa& ~ompany as"Rhoplex AG-61" havin~
a sollds content o~ 46.5% by welght was added wlth
stlrrlng 9.Og water and 3.5g of a 2% by welght aqueous
~olutlon of hydroxyethy~ cell~lo~e thickenlng agent.
To thls m~xture ~as then added wlth stlrrlng 100 mg o~
l-elcosanol that had been dls401ved ln 2 grams of
methyl ethyl ketone. A control ~ormulation waR
prepared simllarly but uslng 2 grams o~ methyl ethyl
ketone wlthout l-elco~anol.
The rates of water evaporatlon of the test and
control formulations at 25C and 55S relative humldity
were mea3ured gravlmetrlcally. The open tlme of the
samples ~a8 measured by brushlng fre~h coatlng at
varlous elapsed times perpendlcular to and including
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the edge o~ a ca~t fllm of the coatlng. Open time 19
de~lned a~ the time at whlch a dlstlnct boundary line
1~ left at the edge Or the castlng, lndicatlng that
drying at lts edge ha3 occurred to 3uch extent ~hat the
brushed ~ilm doe~ not ea~lly mlx ln. The re~ults of
thl~ evaluatlon are pre~ented on Table III.
T~E III
Coat ~ with
Control Coat~ elco~nol
Rate of water evaporatlon 0.072 0.037
(mg/mLn.-cm2 )
Open t ~ (mlnutes) 1.0 2.5
EXAMPLE XI I I
l-eicossnol was evaluated as an evaporatlon
~uppres~ant ln a whlte acryllc latex palnt. An
emul310n of l-e~co~anol was prepared by firYt
dissolvlng at 80C a mixture of 6.0 gram~ l-elco~anol,
1.4g ~tearlc acld, 1.4g of 30% ammonla, and 10g of
allphatlc hydrocarbon solvent (~old by Exxon Co. a~
"Nbrpar 13"*~, followed by ~tlrring ln 60g o~ water
preheated to 80C, and qulckly coollng the mlxture ln
an ice bath. ~hite palnts were ~hen formulated
* Trade mark
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accordlng to the following reclpe:
Ingredient ~ ~nt ~P-rts by we ht)
Paint containing
Control Paint l-eico anol
Mix in "C~wles Dissolver":
Water 35.7 35.7
Dlspersant 6.2 6.2
Wetting Agent 1.4 1.4
Antl~oamer 2~0 2.0
Rutile T102 154.0 154.0
Let Down with:
Acryllc Latex (40.9% solid~) 478.1 478.1
Water 302.0 223.0
Thickener 17.5 15.5
AmmDnlum hydroxide (3~%) 7.2 6.8
l-elcosanol emul~lon 0.0 78.8
(volume % sollds) 25 25
Water evaporatlon rates and open tlme of the palnt
samples were mea~ured a~ in Example XII, and the
re~ults are presented ln ~able IV.
?
TAELE IV
Coating with
Control_Coatl~ el008anO
R~te o~ water evaporation 0.067 0.038
(mg~mln _cm2)
Open-time (minutes) 2 10
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EXAMPLE XIV
l-elcosanol wa~ evaluated for it~ effectiveness ln
reduclng sklnning of a stored latex. 130g allquots of
46.5% by weights ~ollds content acrylic latex ~Rhoplex
s AC-61) were charged to 1/2 pint (7 cm diameter) palnt
cans. l-eicosanol was added to the above samples uslng
variou~ techniques of addltion. The isamples were
monltored 6ravimetrically for water 10~9 and examined
for degree of sklnnlng over the surface for a 24-hour
and a 48-hour perlod. The results of thls evaluatlon
are presented ln Table V.
T~E V
l-elcosanol addition We~t Loss Skinni~
24-hr. 48-hr. 24-hr. _8-hr~
1. None 4.3g 8.4g severe severe
2. ~one (~pread 2g hexane 4.0g 8.3g severe severe
on surface)
3. Spread 2g Or 0.2% eicosanol 0.5g l.Og none very
ln he ~ e on sur~ace slight
4. Spread O.lg of 0.2~ 1.35g 3.4g sli~ht sllght
elcosanol in hexane on
surface
5. Stlrred in 2g of 1.55g 3.1g slight slight
eico~ol~ emulsion
prepar~ in E~le XIII
EXAMPLE XV
l-eicosanol wa~ evaluated for lmprovement of film
~ormation/adh~sion in a whlte acryllc latex palnt,
Exterior whlte latex palnts were ~ormulated accordlng
to the rollowlng reclpe:
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- 18 -
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ount (part.q by weight)
Palnt with
IngredientControl Paint Eicosanol
M1X In Cowles Dissolver:
Thickener ~100%) 3.0 3.0
Water 120.0120.0
Dispersant 1.5 1.5
Wetting Agent 2.5 2.5
Anti~o~mer 225.0225.0
Rutile TiO2 25.0 25.0
Zinc Oxide 25.0 25.0
Aluminum Silicate 147.3147.3
Clay 50-0 50-0
Silica Silicate 5.0 5.0
Let Down With:
Acrylic Latex (Rhoplex AC-61) 398.0398.0
Antlfoam~r 3.0 3.0
Coalescent 3.0 3.0
Water 121.2105.2
Thlckener t2.5% a~ueous solution) 64.o 0.0
l-Elcoisanol emulqlon (prepared in 0.0 80.0
Example XIII)
Propertle~
Volume % ~olld~ 36 36
~5 Stormer n sco ity (KU) 77 69
The palnt qamples were brushed at natural spread rate
over predried (250F for 30 minutes in an oven) whlte
plne lnslde a laboratory hood, and allowed to dry
lnslde the hood. The paint film~ were monitored for
the rate of drylng and examlned ~or fllm cracking after
complete drying. The re~ults of thls evaluation are
pre~ented ln Table VI. It can be seen that the palnt
containlng l-eicosanol ha~ a longer drylng time whlch
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gives the acryllc latex particles a longer time to
coalesce and adhere to substrate, thus reduclng film
cracking.
TABLE VI
Paint wlth
Control Paint Eicosanol
Drying time (minuteæ) 5 9
Film Cracking Moderate None
The above examples demonstrate the e~fectiveness
of unbranched, allphatlc long chaln, surface-actlve
compounds as evaporation suppressants in aqueous
polymer compositionæ to increa~e open time, reduce
sklnning, and improve film formation/adhesion.
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