Note: Descriptions are shown in the official language in which they were submitted.
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LATEX POLYMER COMPOSITIONS
FIELD OF THE INVENTION
This invention relates to novel latex polymers and aqueous
compositions containing the same which are capable of providing
exceptionally high water resistance when used in coatings and other
applications. The aqueous latex compositions containing the novel
polymers are prepared by the emulsion polymerization of ethylenically
unsaturated monomers including highly branched neo vinyl esters and
ethylenically unsaturated reactive surfactants. Aqueous latex
compositions containing these polymers are especially suitable for use
in coatings, adhesives, caulks and sealants where excellent water
resistance is desirable. Such polymers are also suitable for use as
additives, modifiers, inks, binders for dyes and pigments, and textile
treatments.
BACKGROUND OF THE INVENTION
Water resistance is an important property for protective
compositions used as surface coatings, adhesives, caulks and sealants.
Water is known to penetrate porous materials and contribute to their
deterioration. Examples of such damage include warping and swelling
of wood, cracking and spalling of concrete and masonry caused by
freeze/thaw cycles and dissolved salts and the corrosion of reinforcing
steel in concrete caused by chloride ions found in deicing salts.
Protective compositions containing a variety of polymers have been
suggested for use in eliminating or reducing such damage. Many of
these compositions require the presence of organic solvents. Because of
recognized environmental toxicity and flammability problems, a
significant effort is being made to replace these solvent-based systems
with water based systems.
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Considerable effort has been devoted to the development of
water-based polymer systems which have sufficient water resistance to
be useful in protective coating compositions. Such water-based polymer
compositions are prepared by well known emulsion polymerization
techniques which normally require the presence of one or more
surfactant, often in combination with water soluble protective colloids,
to emulsify the monomer reactants and stabilize the final polymer
latex product. Conventional surfactants do not react with the
monomers and residual amounts of these surfactants in coating and
other protective compositions can have a negative effect on properties
such as water resistance.
These surfactants can migrate through the polymer and form
aggregates in the polymer matrix. The surfactants can also migrate to
the dried polymer surface as well as to the polymer and substrate
interface. Surfactants and water soluble protective colloids are water
sensitive materials which can cause blushing and whitening as well as
swelling of dried latex polymer when in contact with water. Blushing,
whitening and swelling of dried latex polymers by water can destroy
the integrity of the polymer latex and eventually causing the protective
composition to fail. It would be desirable to have a polymer latex made
by emulsion polymerization which does not have the water sensitivity
resulting from the presence of the conventional surfactants or
protective colloids required to emulsify monomers and stabilize the
polymer latex during polymerization and post handling.
An improvement in the water resistance of protective
compositions containing aqueous polymer latexes has been achieved by
substituting a class of compounds known as reactive surfactants for
part or all of the conventional surfactants used in the preparation of
the polymer latexes. The reactive surfactants are covalently bonded to
the latex polymer and thus are not subject to migration and other
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problems associated with conventional surfactants. The reactive
surfactants are similar to conventional surfactants with surface
activity imparted by the hydrophilic and hydrophobic moieties in the
molecules. The hydrophilic moiety can be either ionic or nonionic in
nature. Reactive surfactants also contain ethylenically unsaturated
double bonds for free radical reaction with other monomers during
polymerization. U.S. Pat. No. 4,224,455 describes the preparation of
reactive surfactants that are comprised of ring sulfonated half esters of
malefic anhydride with alkoxylated alkyl arylols and their applications
to impart stability to polymers made by emulsion polymerization. U.S.
Pat. No. 4,075,411, 5,563,214, 5,296,627, 5,332,854, 4,939,283,
5,324,862, 4,814,514 are examples describing other representative
types of reactive surfactants and their use as emulsifiers in emulsion
polymerization.
In an article presented at Eurocoat 95, titled "A New Class of
Latex Binders for Water-Bourne Wood Coatings", M. Slinckx and S.
Spanhove , International Congress Eurocoat, Lyon, pp. 19-21, highly
branched neo vinyl esters such as vinyl neodecanoate and vinyl
neononanoate are described as providing improved water resistance
when incorporated into acrylic polymers. This article discloses such neo
vinyl esters polymerized with methyl methacrylate and 2-ethylhexyl
acrylate. These monomers are emulsion polymerized in the presence of
conventional surfactants. While such compositions exhibit an
improved water resistance, they are not as good as solvent based
systems and the neo vinyl esters are recognized as being difficult to
polymerize with certain monomers. Accordingly, the protective
compositions industry is still seeking an aqueous polymer system
which offers the exceptional water resistance and exterior durability
provided by solvent based systems.
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SUMMARY OF THE INVENTION
This invention relates to novel latex polymers having excellent
water resistance comprising:
(a) at least one neo vinyl ester,
(b) at least one reactive surfactant,
(c) optionally, at least one ethylenically unsaturated
monomer which is different from (a) or (b), and
(d) optionally, at least one ethylenically unsaturated
monomer which is different from (a), (b) or (c).
The novel latex polymers are prepared by emulsion
polymerization of the ethylenically unsaturated monomers. The
aqueous compositions containing the novel latex polymers are useful to
impart superior water resistance to architectural coatings and in other
applications where protection against water is desirable.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to novel latex polymers and aqueous
compositions containing the same made by emulsion polymerization
which exhibit exceptionally high water and alkali resistance. The novel
latex polymers of this invention comprise (a) about 5 to about 99.9
percent by weight of highly branched neo vinyl esters; (b) 0 to about
94.9 weight percent of one or more alkyl esters of acrylic or methacrylic
acid; (c) 0 to about 50 weight percent of other ethylenically
unsaturated monomers; and (d) about 0.1 to I0.0 weight percent of one
or more ethylenically unsaturated reactive surfactants.
The highly branched neo vinyl esters useful in this invention
typiaclly contain from 8 to 18 carbon atoms and are prepared from
suitable highly branched carboxylic acids by methods well known in
the art. Commercially available neo vinyl ester products are normally
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a mixture containing a predominance of one species. Suitable neo vinyl
ester compositions for use in the present invention include, but are not
limited to, vinyl neononanoate (VeoVa 9), vinyl neodecanoate (VeoVa
10), and vinyl esters of mixed branched carboxylic acids (VeoVa 11),
sold by Shell Chemical Company, and vinyl esters of mixed C10-C13
branched carboxylic acid, (EXXAR Neo-12) sold by Exxon Chemical
Corp., and the like.
The aqueous polymer compositions of the present invention may
contain as little as about 5% by weight of the highly branched neo
vinyl esters to as much as about 99.9% by weight. When polymerized
with other comonomers such as acrylates, the neo vinyl esters are
present preferably in an amount of from about 10% to about 80%, and
most preferably from about 15% to about 70% by weight, based on the
weight of all monomers. Useful polymers have been prepared
containing about 98.7% by weight of neo vinyl esters and 1.3% by
weight of one or more reactive surfactants.
The reactive surfactants useful in the novel latex polymers of
the present invention may be any compound which contains
ethylenically unsaturated double bonds for free radical reaction with
the neo vinyl esters and other monomers during polymerization while
also containing hydrophilic and hydrophobic moieties similar to
conventional surfactants which impart surface activity. Example of
compounds which are useful as reactive surfactants in the novel latex
polymers of the present invention include the compounds prepared by
reacting sulfonated half esters of malefic anhydride with alkoxylated
alkyl arylols described in U.S. Pat. No. 4,224,455; nonyl
phenoxy(ethyleneoxy)io-4o ethyl acrylate, nonyl phenoxy(ethyleneoxy)io-
4o ethyl methacrylate and nonyl phenoxy(ethyleneoxy)io-4o crotonate
which are disclosed in U.S. Pat. No. 4,075,411; the compounds based
on N-acryloyl-piperazine disclosed in U.S. Pat. No. 5,563,214; the
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compounds having a hydrophobic portion having terminal ethylenic
unsaturation and a hydrophilic portion containing a poly(alkyleneoxy)
segment and an ionic segment described in U.S. Pat. No. 5,296,627;
the compounds containing nonylphenoxy propenyl moieties described
in U.S. Pat. No. 5,332,854 and U.S. Pat. No. 5,324,862; the compounds
containing allylic unsaturation described in U.S. Pat. No. 4,939,283
and U.S. Pat. No. 4,814,514; the disclosure of all of the above patents
being incorporated herein by reference, and sodium dodecyl allyl
sulfosuccinate (Trem LF-40) sold by Fienkel Corporation.
Generally, the amount of ethylenically unsaturated reactive
surfactants incorporated into the latex polymers of the present
invention will range from about 0.1% to about 10% by weight based on
the total weight of the polymer, and preferably from about 0.5% to
about 8% by weight.
Reactive surfactants with nonylphenoxy propenyl groups or
other groups structurally similar to styryl groups, behave similarly to
styrene in copolymerization with highly branched neo vinyl esters, i.e.
polymerization of the neo vinyl ester monomer is severely retarded in
the presence of these compounds. It has been noted that the presence
of certain other monomers such as the alkyl esters of acrylic and
methacrylic acid appear to function as bridge between the branched
neo vinyl esters and the reactive surfactants containing groups
structurally similar to styryl groups allowing stable latexes to be
made. Other reactive surfactants with ethylenically unsaturated
moieties not similar to styryl groups generally react well in or show
less retardation toward the polymerization of highly branched neo
vinyl esters. Copolymers of highly branched neo vinyl esters with other
ethylenically unsaturated monomers and all vinyl ester polymers and
copolymers can be made with these reactive surfactants. Conventional
non-reactive surfactants may also be present in the novel latex
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polymers of the present invention, but minimal use of such surfactants
is preferred to achieve the best results in the practice of this invention.
Comonomers which may be copolymerized with the highly
branched neo vinyl esters and reactive surfactants include those
ethylenically unsaturated addition monomers readily recognized by
one skilled in the art as useful in the preparation of latex polymers.
Particularly useful monomers include ethylenically unsaturated alkyl
esters of acrylic and methacrylic acid, such as, but not limited to, one
or more of the following: n-butyl acrylate, isobutyl acrylate, isopropyl
acrylate, ethyl acrylate, methyl acrylate, 2-ethylhexyl acrylate, 2-
ethylhexyl methacrylate, isooctyl acrylate, nonyl acrylate, oleyl
acrylate, dodecyl acrylate, stearyl acrylate, methyl methacrylate, ethyl
methacrylate, n-butyl methacrylate, nonyl methacrylate, lauryl
methacrylate, isobutyl methacrylate, isobornyl methacrylate, isobornyl
acrylate, pentyl acrylate, and mixtures thereof. Generally, the amount
of ethylenically unsaturated alkyl esters of acrylic and methacrylic
acid present in the novel latex polymers of the present invention
ranges from about 0% to about 95% by weight based on the total
weight of the polymer. Particularly good results are obtained when
such monomers are present in an amount of from about 20% to about
90°/ by weight, preferably from about 30% to about 80% by weight,
based on the total weight of the polymer.
The inventors have found that highly branched neo vinyl esters
react slower when copolymerized with alkyl esters of acrylic and
methacrylic acid due to the differences in monomer reactivity ratios.
The alkyl esters of acrylic and methacrylic acid are nearly completely
reacted shortly after monomer addition has been completed during
polymerization, while there typically will be substantial measurable
amounts of highly branched neo vinyl esters which remain unreacted.
The inventors have found that the substantial measurable amounts of
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unreacted highly branched neo vinyl esters which remain can be
driven towards completion by adding additional initiators and
continuing the polymerization. By following this procedure, structured
latex particles or core/shell latex particles may be obtained with highly
branched neo vinyl esters deposited on the outer layers or shell layers
of latex particles. Thus another feature of this invention is a chemical
means to prepare structured latex particles with an outer shell layers
or layers which have very low oxygen content and low water
permeability.
Other ethylenically unsaturated monomers which may be used
in the preparation of the latex polymers of the present invention
include, but are not limited to: vinyl esters, for example, vinyl acetate,
vinyl propionate, vinyl formate, vinyl n-butyrate, vinyl laurate, vinyl
stearate, vinyl pivalate, vinyl 2-ethylhexanoate, and the like; vinyl
ethers, for example, methylvinyl ether, ethylvinyl ether, butylvinyl
ether, and the like; allyl monomers, for example, allyl acetate, allyl
propionate, allyl lactate, allyl amines, and the like; olefins, such as
ethylene, propylene, 1-butene, 1-pentene, 1-hexene, and the like. Other
vinyl monomers, functional monomers, and crosslinking monomers, for
example, acrylic acid, methacrylic acid, acrylonitrile, styrene, p-
methyl styrene, vinyl and vinylidene halides such as vinyl chloride and
vinylidene chloride, sodium vinyl sulfonate, sodium styrene sulfonate,
sodium allyl ether sulfate, acrylamide, methacrylamide, sodium 2-
acrylamide-2-methyl-propane sulfonate (AMPS), diacetone acrylamide,
N-methylol acrylamide, N-methylol methacrylamide, 2-sulfoethyl
methacrylate, 2-sulfopropyl methacrylate, hydroxyethyl methacrylate,
hydroxypropyl methacrylate, 2,2,4-trimethyl-1,3-pentanediol
monomethacrylate, 2-cyanoethyl acrylate, diethylaminoethyl acrylate,
dimethylaminoethyl methacrylate, glycidyl acrylate, glycidyl
methacrylate, acetoacetoxyethyl methacrylate, allylacetoacetamide,
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allyl methacrylate, trimethylol propane trimethacrylate, trifluoroethyl
methacrylate, triallyl cyanurate, triallyl isocyanurate, sodium
methallyl sulfonate, ethyl imidazolidone methacrylate, methoxy ethyl
acrylate, methacrylamidoethylethyleneurea, allylic derivatives of
aminoethylethyleneurea (Sipomer WAM), cyclic imides derivatives of
urea/ureido monomers (Cylink WAM; WO 97/49676), (3-carboxyethyl
acrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate,
trimethylolpropane trimethacrylate, pentaerythritol triacrylate,
vinyltrimethoxysilane, vinyl-tris(2-methoxyethoxysilane), gamma-
methacryloxypropyltrimethoxysilane, vinylpyrrolidone, ethylene
methacrylate phosphate, malefic acid, fumaric acid, itaconic acid,
dimethyl maleate, di-n-butyl maleate, diethyl maleate, diethylhexyl
maleate, diethyl fumarate, butadiene, chloroprene, isoprene,
polybutene and poly(isobutylene-co-butene) oligomers containing
ethylenically unsaturated double bonds (Indopol series from Amoco
Chemical Company), 1,4-butanediol dimethacrylate, diallyl maleate,
divinyl adipate, crotonic acid, mixtures thereof, and the like. Typically,
these additional ethylenically unsaturated monomers are present in an
amount of from about 0% to about 50% by weight, based on the total
weight of the polymer, and more typically up to about 30% by weight.
Any known method of emulsion polymerization may be used to
prepare the novel latex polymers of the present invention including
semi-batch, staged feed, power feed, full batch, continuous, seeded
emulsion polymerization or any other suitable procedure. Any suitable
polymerization conditions may be used. Typically, the reaction
temperature will range from about 0 °C to about 100 °C, and
preferably
from about 40 °C to about 90 °C. The polymerization normally
will be
conducted using polymerization initiators. Suitable polymerization
initiators include, but are not limited to: water-soluble persulfates and
peroxides capable of generating free radicals such as ammonium
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persulfate, sodium persulfate, potassium persulfate, hydrogen
peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, peracetic acid,
perbenzoic acid, diacetyl peroxide, t-butyl peracetate, t-butyl
perbenzoate, and the like, azo initiators, such as 2,2-
azobisisobutyronitrile, and the like, and other radiation and transition
metal compounds capable of generating free radicals. The amount of
such free radical initiators used generally ranges from about 0.05% to
about 6% by weight based on the weight of all monomers present.
Alternatively, redox initiators may be used, especially when
polymerization is carried out at lower temperatures. For example,
reducing agents may be used in addition to the persulfate and peroxide
initiators mentioned above. Typical reducing agents include, but are
not limited to: alkali metal salts of hydrosulfites, sulfoxylates,
thiosulfates, sulfites, bisulfites, reducing sugar such as glucose,
sorbose, ascorbic acid, erythorbic acid, and the like. In general, the
reducing agents are used at levels from about 0.01% to about 6% by
weight.
Various additives can be added before, during or after
polymerization. These include conventional surfactants, buffering
agents, neutralizing agents, defoamers, chain-transfer agents,
plasticizers and polymeric stabilizers. Suitable conventional
surfactants include, but are not limited to, one or more: alkyl and/or
aryl sulfates, sulfonates, phosphates, or carboxylates such as sodium
lauryl sulfate, sodium salt of alkylaryl polyether sulfates, linear
alcohol ethoxylate phosphates, alkylphenol ethoxylate phosphates, and
the like; oxyalkylated fatty amines, fatty acid amides and/or
monoalkylphenols such as oxyethylated lauryl alcohol, oxyethylated
oleyl alcohol; oxyethylated stearyl alcohol, oxyethylated p-iso-
octylphenol, oxyethylated p-n-nonylphenol, oxyethylated p-n-
dodecylphenol, and the like; fluorocarbon-based surfactants, such as
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ammonium perfluoroalkyl sulfonates, potassium perfluoroalkyl
sulfonates, amine perfluoroalkyl sulfonates, ammonium perfluoro alkyl
carboxylates, potassium fluorinated alkyl carboxylates, fluorinated
alkyl polyoxyethylene ethanols, fluorinated alkyl alkoxylates,
fluorinated alkyl esters, and the like. The amount of conventional
surfactants may range from about 0% to about 5°/ by weight, and
preferably from about 0% to about 2% by weight. Any polymeric
stabilizers capable of stabilizing latex particles may be used, these
include, but not limited to, cellulose ethers such as
hydroxyethylcellose, alkyl modified hydroxyethylcellose, aryl alkyl
modified hydroxyethylcellose, carboxymethylcellose, alginate, starch,
polyvinyl alcohol), polyacrylates, polymethacrylates, styrene-malefic
anhydride copolymers, polyvinylpyrrolidones, polyacrylamides,
polyethers, and the like. The amount of polymeric stabilizers may
range from about 0% to about 5% by weight, and preferably from
about 0% to about 2°/ by weight.
The latex polymers of the present invention are normally
obtained as an aqueous composition by emulsion polymerization.
Techniques well known to the skilled artisan may be employed to
obtain a Iatex polymer of the present invention having the desired
physical characteristics required for a particular application. Useful
aqueous composition containing the latex polymers of the present
invention will typically have a solids content of from about 10% to
about 70% by weight based on the total weight of the composition. The
latex polymers of the present invention may be tailored to obtain any
desired molecular weight and viscosity. Typically, the Iatex polymers of
the present invention will have a viscosity in the range of about 10 to
about 5000 cps. The pH of an aqueous composition containing the latex
polymer of the present invention will normally be within the range of
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about 2 to about 12, while the particle size of the latex polymer will
normally be in the range of from about 0.02 to about 2.0 microns.
The novel latex polymers of the present invention can be tailored
for use in many applications. Representative examples including
architectural coatings for wood including paints, varnishes, stains and
clear sealers; architectural coatings for other substrates such as
plaster, concrete, brick and metal; appliance finishes, automotive
finishes, coil coatings, can coatings, marine coatings, aircraft finishes,
paper coatings and various adhesives including pressure sensitive
adhesives. Other potential uses for the novel latex polymers include
caulks and sealants, additives and modifiers, binders for dyes and
pigments, cement modifiers, waterproofing agents, overprint
varnishes, flexographic inks and polishes for shoes, floors and
furniture.
EXA11~IPLES
The following examples are offered to illustrate the novel
aqueous polymer compositions of this invention and are not intended to
be limiting in scope. All of the parts, percentages and proportions
referred to herein are by weight unless otherwise indicated .
EXAMPLE 1
This example illustrates the preparation of an aqueous latex
polymer composition with alkyl esters of acrylic and methacrylic acid
in the presence of conventional surfactants. A reaction kettle was
equipped with an agitator, thermocouple, reflux condenser, nitrogen
inlet, water jacket, and suitable addition ports. A monomer
preemulsion was prepared by mixing together 60.1 parts of deionized
water, the conventional surfactants 0.37 part of a sodium lauryl sulfate
(Rhodapon UB supplied by Rhodia Company) and an ethoxylated
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nonylphenol (Tergitol NP-15 supplied by Union Carbide Corp.), 46.52
parts of n-butyl acrylate, 52.13 parts of methyl methacrylate, and 1.34
parts of methacrylic acid. The reaction kettle was charged with 72.1
parts of deionized water, 1.12 parts of Rhodapon UB and 2.26 parts of
Tergitol NP-15, 2.75°/ of the above prepared monomer preemulsion,
and 0.05 part of an ammonium persulfate in 1.22 parts of deionized
water. The kettle was heated to 80°C with continued agitation and
nitrogen purge. Twenty minutes later, the rest of monomer
preemulsion along with 0.55 part of an ammonium persulfate in 6.09
parts of deionized water in separate feed stream were added to the
reaction kettle over a three hour period. The temperature was
maintained at 80°C for 30 minutes more after all additions. 0.29 part
of
t-butyl hydroperoxide in 2.44 parts of deionized water and 0.12 part of
sudium formaldehyde sulfoxylate in 2.52 parts of deionized water were
added to the reaction kettle over a one hour period. The latex was then
cooled to room temperature. The properties of the latex obtained are
presented in Table 1.
EXAMPLE 2
This example describes the preparation of an aqueous latex
polymer composition with alkyl esters of acrylic and methacrylic acid
in the presence types of conventional surfactants which are different
from those used in Example 1. The equipment, procedure and
ingredients described in Example 1 were used, except that the
conventional surfactants employed to prepare the monomer
preemulsion were 0.24 part of an ammonium salt of sulfated
nonylphenoxy poly(ethyleneoxy) ethanol (ABEX EP-110 supplied by
Rhodia Company) and 0.57 part of a nonylphenoxy poly(ethyleneoxy)
ethanol (Igepal CO-630 supplied by Rhodia Company). 1.12 parts of
ABEX EP-110 and 2.26 parts of Igepal CO-630 were charged to the
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reaction kettle initially. The properties of the latex obtained are
presented in Table 1.
EXAMPLE 3
This example describes the preparation of an aqueous latex
polymer composition with alkyl ester of acrylic and methacrylic acid in
the presence of ethylenically unsaturated reactive surfactants. The
equipment, procedure and ingredients described in Example 1 were
used, except that in place of the conventional surfactants, the following
ethylenically unsaturated reactive surfactants were employed to
prepare the monomer preemulsion. 0.07 part of a nonylphenoxy
propenyl polyethoxylate sulfate (Hitenol BC-10 supplied by DKS
International, Inc.) and 0.57 part of a nonylphenoxy propenyl
polyethoxylated alcohol (Noigen RN-10 supplied by DKS International,
Inc.). 0.34 part of Hitenol BC-10 and 2.26 parts of Noigen RN-10 were
charged to the reaction kettle initially. The properties of the latex
obtained are presented in Table 1.
EXAMPLE 4
This example describes the preparation of an aqueous latex
polymer of a highly branched neo vinyl ester with alkyl esters of acrylic
and methacrylic acid in the presence of conventional surfactants. The
equipment and procedure described in Example 1 were used. A
monomer preemulsion was prepared by mixing together 58.38 parts of
deionized water, 0.58 part of an ammonium salt of sulfated
nonylphenoxy poly(ethyleneoxy) ethanol (A.BEX EP-110 supplied by
Rhodia Company) and 1.13 parts of a nonylphenoxy poly(ethyleneoxy)
ethanol (Igepal CO-630 supplied by Rhodia Company) which are
conventional surfactants, 37.52 parts of vinyl neodecanoate (VeoVa 10
supplied by Shell Chemical Company), 25.82 parts of n-butyl acrylate,
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35.32 parts of methyl methacrylate, and 1.34 parts of methacrylic
acid. The reaction kettle was charged with 72.1 parts of deionized
water, 0.88 part of ABEX EP-110 and 1.70 parts of Igepal CO-630, 2.75
percent of the above prepared monomer preemulsion, and 0.05 part of
ammonium persulfate in 1.22 parts of deionized water. The kettle was
heated to 80°C with continued agitation and nitrogen purge. Twenty
minutes later, the rest of monomer preemulsion along with 0.55 part of
ammonium persulfate in 6.09 parts of deionized water in separate feed
stream were added to the reaction kettle over a three hour period. The
free VeoVa 10 at the end of addition was found to be about 5.5 percent.
The free methyl methacrylate was found to be about 0.13 percent and
n-butyl acrylate was not detectable. The temperature of the reaction
kettle was maintained at 80°C for 30 minutes more and 0.29 part of t-
butyl hydroperoxide in 2.44 parts of deionized water and 0.12 part of
sodium formaldehyde sulfoxylate in 2.52 parts of deionized water were
then added over one hour period. The residual methyl methacrylate
was 0.02 percent while VeoVa 10 and n-butyl acrylate were not
detectable at the end of additional initiator addition. Thus the
additional intiator was capable of driving the VeoVa 10 reaction
towards completion. It was possible that structured latex particles or
core/shell latex particles were obtained with highly branched neo vinyl
esters deposited on the outer layers or shell layers of the latex
particles. The properties of the latex obtained are presented in Table 1.
EXAMPLE 5
This example illustrates the novel latex polymers of the present
invention. It describes the preparation of an aqueous latex polymer of a
highly branched neo vinyl ester polymerized with alkyl esters of acrylic
and methacrylic acid in the presence of ethylenically unsaturated
reactive surfactants containing nonylphenoxy propenyl groups. The
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equipment, procedure and ingredients described in Example 4 were
used, except that the following ethylenically unsaturated reactive
surfactants were employed in place of the conventional surfactants to
prepare the monomer preemulsion; 0.15 part of a nonylphenoxy
propenyl polyethoxylate sulfate (Hitenol BC-10 supplied by DKS
International, Inc.) and 1.13 part of a nonylphenoxy propenyl
polyethoxylated alcohol (Noigen.RN-10 supplied by DKS International,
Inc.). 0.26 part of Hitenol BC-10 and 1.70 parts of Noigen RN-10 were
charged to the reaction kettle iniatially. At the end of monomer
preemulsion and initiator additions, the free VeoVa 10 was found to be
3.5 percent, while free methyl methacrylate and n-butyl acrylate were
0.03 and 0.02 percent, respectively. The temperature of the reaction
kettle was maintained at 80°C for 30 minutes more and 0.29 part of t-
butyl hydroperoxide in 2.44 parts of deionized water and 0.12 part of
sodium formaldehyde sulfoxylate in 2.52 parts of deionized water were
then added over one hour period. The residual VeoVa 10 was found to
be about 0.07 percent while methyl methacrylate was 0.02 percent and
n-butyl acrylate was not detectable. In this example, structured latex
particles or core/shell particles may be made with highly branched neo
vinyl esters deposited on the outer layers or shell layers of the latex
particles. Surprisingly, VeoVa 10 polymerization was not retarded in
the presence of reactive surfactants containing nonylphenoxy propenyl
groups as one skilled in the art might have expected. The properties of
the latex obtained are presented in Table 1.
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Table 1: Latex
Compositions
and Properties
Example Example Example Example Example
1 2 3 4 5
n-Butyl acrylate 46.52 46.52 46.52 25.82 25.82
Methyl 52.13 52.13 52.13 35.32 35.32
methacrylate
VeoVa 10 (a) . 37.52 37.52
Methacrylic acid 1.34 1.34 1.34 1.34 1.34
Rhodapon UB (b) 1.49
Tergitol NP-15 2.83
(c)
ABEX EP-110 (d) 1.36 1.46
Igepal CO-630 2.83 2.83
(e)
Hitenol BC-10 0.41 0.41
(f)
Noigen RN-10 (g) 2.83 2.83
Latex solids content,41.02 42.27 39.24 41.39 41.19
wt%
pH 2.12 2.11 2.13 2.18 2.18
Particle size, 0.12 0.16 0.19 0.14 0.13
micron
Brookfield viscosity,20 20 20 20 20
cps
(a) Vinyl neodecanoate supplied by Shell Chemical Company.
(b) Sodium lauryl sulfate (30% in aqueous solution) conventional
surfactant supplied by Rhodia Company.
(c) Ethoxylated nonylphenol conventional surfactant supplied by
Union Carbide Corp.
(d) Ammonium salt of sulfated nonylphenoxy poly(ethyleneoxy)
ethanol (30% in aqueous solution) conventional surfactant supplied by
Rhodia Company.
(e) Nonylphenoxy poly(ethyleneoxy) ethanol conventional
surfactant supplied by Rhodia Company.
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(f) Nonylphenoxy propenyl polyethoxylate sulfate reactive
surfactant supplied by DKS International, Inc.
(g) Nonylphenoxy propenyl polyethoxylated alcohol reactive
surfactant supplied by DKS International, Inc.
Test formulations were prepared to examine the water repellent
effectiveness of each latex shown in Table 1. Each test formulation
contained 100 parts of the latex. to be tested, 106.5 parts of deionized
water and 4.5 parts of diethylene glycol monobutyl ether. Each test
formulation was equilibrated for 24 hours before testing.
The water repellent effectiveness of each latex was measured
gravimetrically. Water absorption was tested using matching 1 by 2 by
0.25 inch Southern Yellow Pine boards. Four boards were treated with
each latex formulation by immersing the boards in the latex
formulation for three minutes. The boards were then allowed to dry for
three days in a room maintained at constant temperature and
humidity (72°F and 50% humidity). Four untreated boards were used
as a control. All of the treated and untreated boards were weighed,
immersed in deionized water for 30 minutes, and weighed again. The
difference in weight represents the amount of water absorbed. The
water repellent effectiveness (WRE) of each latex is determined by
subtracting the weight of water absorbed by the board treated with
the latex from the weight of the water absorbed by the untreated
board, dividing that by the weight of water absorbed by the untreated
board and multiplied by 100, as shown in the equation below.
WRE = (water absorbed by untreated control - water absorbed by treated board)
X 100
(water absorbed by untreated control)
The average of the water repellent effectiveness of the four boards
treated with each latex of the examples is shown in Table 2. The
results show that the water resistance of the novel aqueous polymer
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compositions of the present invention represented by Example 5 are
significantly better than the water resistance of the prior art
compositions.
Table 2: Water Repellent Effectiveness
Example Water Repellent Effectiveness
1 43.69
2 46.69
3 57.41
4 72.75
5 81.28
The following recipes are examples
of typical architectural
coating formulations employing
the novel latex polymer of
Example 5:
Clear Sealer for Wood or Concrete
J~redients Gallons
Water 43.59
Glycol 3.95
Ammonia 0.11
Wax Additive 2.89
CoSolvent 1.09
Antioxidant 0.25
Mildewcide 0.87
Preservative 0.17
Latex of Example 5 47.05
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Wetting Agent 0.02
Total 100
Weight Solids 20
White Paint/Stain for Wood and Concrete
Ingredients Gallons
Water 42.00
Preservative 0.40
Glycol 4.00
Rheology Modifier 0.40
Dispersant 1.50
Defoamer 0.20
Surfactant 0.20
Prime Pigment 5.00
Extender Pigment 10.00
Latex of Example 5 34.00
CoSolvent 1.50
Mildewcide 0.76
Total 100
Weight Solids 47
