Emulsified comb polymer and defoaming agent composition and method of making same

Exemplary emulsion admixture for use in hydraulic cement compositions formed by emulsifying an antifoaming agent, surfactant, and a comb polymer having a carbon-containing backbone to which are attached cement-anchoring members and oxyalkylene groups. A method of making a stable emulsion admixture comprising the comb polymer, as well as a hydraulic cement composition comprising the admixture, are also described.

FIELD OF THE INVENTION 
The present invention relates to chemical admixtures for use in hydraulic 
cement compositions such as concrete, and more particularly to an 
admixture composition formed by emulsifying an antifoaming agent with a 
"comb" polymer having a carbon-containing backbone to which are attached 
cement-anchoring members and oxyalkylene groups; a method of making a 
stable emulsion admixture comprising the comb polymer; and a hydraulic 
cement composition comprising the admixture. 
BACKGROUND OF THE INVENTION 
It is known to use comb polymers in hydraulic cement compositions. For 
example, in U.S. Pat. No. 5,393,343, incorporated fully herein by 
reference, Darwin et al. disclosed an EO/PO type comb polymer useful as a 
superplasticizer for retaining in concrete a high degree of slump (e.g., 
high flowability) over a sustained period of time without imparting 
significant set retardation. As used herein, the term "EO/PO" is 
synonomous with the term "oxyalkylene group" and serves as a convenient 
short-hand to designate polyoxyalkylene groups (e.g., ethylene 
oxide/propylene oxide copolymers). Thus, for present purposes, the term 
"EO/PO type comb polymer" means and refers to a polymer having a carbon 
backbone to which are attached pendant carboxylate groups (which function 
as cement anchoring groups in the cementitious mixture) and also 
comparatively longer pendant groups or "combs" such as ethylene oxide (EO) 
groups, propylene oxide (PO) groups, and/or a combination of EO/PO groups. 
The pendant groups may be ionic or non-ionic. 
U.S. Pat. No. 5,393,343 also disclosed that a variety of conventional 
cement additives, such as "antifoaming agents," may be mixed with the 
cement composition prior to, along with, or subsequent to the addition of 
the superplasticizer. It is know that EO/PO type comb polymers commonly 
entrain excessive air in the cementitious mixture, and thus antifoaming 
agents were needed. Antifoaming agents exhibit very limited stability in 
aqueous solutions because they are hydrophobic and tend to separate in the 
liquid admixture solution which contains the comb polymer. Commonly used 
antifoaming agents (or "defoamers") include EO/PO type defoamers 
(especially ones rich in PO units), silicones, tri-butyl phosphate, and 
alkylphthalates. The phase instability of the comb polymer and antifoaming 
agent combination requires that they be placed into separate tanks and 
mixed just before incorporation into the cement composition (e.g., 
concrete), or, alternatively, that they be contained in a tank requiring 
constant stirring. In any event, the admixture solution has a short shelf 
life, creating inconvenience and added expense for the concrete 
preparation operation. 
European Patent Application No. 0 725 043 (A2) of Sandoz Ltd. teaches that 
antifoaming agents, such as certain polyalkylene glycols or derivatives 
thereof, can be grafted as side chains directly onto a carbon backbone 
along with side chains comprising an oligoalkyleneglycol and/or 
polyalcohol to form the comb polymer. This approach relies on reproducible 
hydrolysis of the ester linkage to allow predictable release of the 
defoaming agent from the carbon-containing backbone. 
UK Patent 2 280 180 A owned by Sandoz Ltd. disclosed the use of a polymer, 
which comprised units derived from unsaturated carboxylic acid monomers, 
in an aqueous solution wherein an oxyalkylene-based defoaming agent 
present during the polymerization of the monomers becomes dissolved or 
dispersed in particles of no greater than 20 .mu.M diameter. Such a 
dispersion, however, may be phase unstable at elevated temperatures and 
during prolonged storage. Commonly known concrete defoamers, such as 
tri-butyl phosphate, even when dispersed are known to coalesce and 
phase-separate. 
In view of the foregoing disadvantages of the prior art, a novel concrete 
admixture comprising an EO/PO type comb polymer and antifoaming agent, 
which allows for predictable air control, and method for making the same, 
are needed. 
SUMMARY OF THE INVENTION 
In surmounting the disadvantages of prior art, the present invention 
provides an emulsion admixture composition for hydraulic cement 
compositions comprising: (a) a comb polymer having a carbon-containing 
backbone to which are attached both cement-anchoring members such as 
carboxylic or carboxylate groups and oxyalkylene groups attached for 
example, by linkages selected from the group consisting of an amide, an 
imide, an ester, and/or an ether; (b) an antifoaming agent emulsified with 
said comb polymer, said antifoaming agents being selected from the group 
consisting of a composition having the formula (PO)(O--R).sub.3 wherein R 
is a C.sub.2 -C.sub.20 alkyl group, a phosphate ester, an alkyl ester, a 
borate ester, a silicone derivative, and EO/PO type defoamer; and (c) one 
or more surfactant(s) operative to stabilize said emulsified comb polymer 
and said antifoaming agent, said surfactant-stabilizers being selected 
from the group comprising (1) an esterified fatty acid ester of a 
carbohydrate selected from the group consisting of a sugar, sorbitan, a 
monosaccharide, a disaccharide, and a polysaccharide, (2) a C.sub.2 
-C.sub.20 alcohol containing ethylene oxide and propylene oxide ("EO/PO") 
groups, and (3) mixtures of such. 
The term "cement anchoring" is meant to refer to ionic bonds formed between 
the polymer's carboxylic(ate) groups and the calcium cations present n the 
cement when the admixture is admixed into a wet cementitious mix, while 
the "EO/PO" pendant "comb" groups on the polymer backbone are believed to 
facilitate the distribution of cement particles within an aqueous 
cementitious mix. Exemplary comb polymers comprise a backbone formed from 
ethylenically-unsaturated monomers, and, as pendant groups on the 
backbone, ethylene oxide (EO) groups, propylene oxide (PO) groups, or 
EO/PO groups in combination. 
An exemplary surfactant comprises an esterified fatty acid ester of a 
carbohydrate, preferably sorbitan monooleate. 
Surprisingly, the inventors have discovered that by emulsifying the comb 
polymer, antifoaming agent, and surfactant together, simultaneously in one 
step, a stable admixture composition be obtained. In other words, all 
three of these critical components--comb polymer, antifoaming agent (not 
grafted onto comb polymer), and surfactant--must be simultaneously present 
during the emulsification process to achieve fine emulsified droplets 
which remain homogeneously distributed throughout the aqueous phase. Thus, 
a conventional antifoaming agent such as tri-butylphosphate, which 
otherwise does not by itself form a stable emulsion in water with the 
surfactant, is able to form a synergistic emulsion of EO/PO-type comb 
polymer/antifoaming agent microdroplets. 
Accordingly, an exemplary method of the invention comprises the 
emulsification of all three of these critical components, along with an 
appropriate amount of dilution water (e.g., 40-90% by weight), wherein the 
amount of comb polymer is 80-98.9% (dry wt), the amount of antifoaming 
agent is 1-15% (dry wt), and the amount of surfactant is 0.05-10.0%, 
preferably 0.1-5.0% (dry wt), in one step to obtain a liquid admixture 
composition which exists as a stable emulsion. Optionally, it is believed 
that the comb polymer may comprise pendant groups having defoaming 
properties in addition to the antifoaming agent (component "b") which is 
separate from the comb polymer but which must be present during the 
emulsion process, as aforesaid, in order to combine with the comb polymer 
and surfactant to form the microdroplets. The present invention also 
relates to cement compositions containing the above admixture. Further 
features and advantages of the invention are described hereinafter. 
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
The term "cement composition" as may be used herein refers to pastes, 
mortars, grouts such as oil well cementing grouts, and concrete 
compositions comprising a hydraulic cement binder. The terms "paste", 
"mortar" and "concrete" are terms of art: pastes are mixtures composed of 
a hydraulic cement binder (usually, but not exclusively, Portland cement, 
Masonry cement, or Mortar cement and may also include limestone, hydrated 
lime, fly ash, blast furnace slag, and silica fume or other materials 
commonly included in such cements) and water; mortars are pastes 
additionally including fine aggregate, and concretes are mortars 
additionally including coarse aggregate. The cement compositions of this 
invention may be formed by mixing required amounts of certain materials, 
e.g., a hydraulic cement, water, and fine or coarse aggregate, as may be 
applicable to make the particular cement composition being formed. 
Exemplary emulsion admixtures of the invention are aqueous solutions 
comprising, in addition to dilution water, (a) a comb polymer a polymer 
backbone to which are attached carboxyl cement anchoring groups and 
non-ionic pendant groups; (b) an antifoaming agent emulsified with the 
comb polymer; (c) and a surfactant operative to provide a stable emulsion 
of the comb polymer and antifoaming agent. These three critical 
components, which are described in further detail hereinafter, are present 
in the following amounts, based on dry weight in the aqueous admixture 
solution (which thus comprises dilution water): comb polymer (80-98.9%); 
antifoaming agent (1-15%); and surfactant (0.1-5%). More preferably, the 
comb polymer is present, based on dry weight in the admixture composition, 
in the amount of 84-97.5%; the antifoaming agent is present in the amount 
of 2-12%; and the surfactant is present in the amount of 0.5-4%. Most 
preferably, the relative amounts are: comb polymer 88-94.3%; antifoaming 
agent 5-10%; and surfactant 0.75-2%. 
Exemplary comb polymers (having pendant EO/PO groups) suitable for use in 
the present invention comprise acrylic polymers or copolymers thereof, 
which may be imidized, such as those taught in U.S. Pat. No. 5,393,343 
assigned to W. R. Grace & Co.-Conn. and incorporated herein by reference. 
The polymer which may be imidized is an "acrylic polymer," by which term 
is meant, for example, a homopolymer or copolymer of acrylic acid, 
methacrylic acid, their alkali metal salts, as well as their C.sub.1 
-C.sub.30 alkyl esters. Additionally, the acrylic polymer reactant and the 
resultant imidized acrylic polymer may contain units derived from other 
singly and doubly ethylenically unsaturated monomers, such as styrene, 
alpha-methystyrene, sulfonated styrene, maleic acid, acrylonitrile, 
butadiene and the like. Such other ethylenically unsaturated monomer 
derived units, when present, can be present in the polymer in amount of up 
to about 20 (preferably, up to about 10) weight percent of the total 
polymer, provided that the resultant imidized acrylic polymer is water 
soluble. 
An exemplary imidized acrylic polymer may be formed such as by reacting an 
acrylic polymer with ammonia or an alkoxylated amine. The amine reactant 
useful in forming the desired acrylic polymer can be selected from ammonia 
or an alkyl-terminated alkoxy amine represented by the formula: 
EQU H.sub.2 N--(AO).sub.n --R" 
in which BO represents a C.sub.2 -C.sub.10 (preferably a C.sub.2 -C.sub.4) 
oxyalkylene group in which O represents an oxygen atom and A represents a 
C.sub.2 -C.sub.10 (preferably a C.sub.2 -C.sub.4) alkylene group or 
mixture; and R" represents a C.sub.1 -C.sub.10 (preferably C.sub.1 
-C.sub.4) alkyl group and n is an integer selected from 1 to 200 and 
preferably from 1 to 70. The reaction conditions and catalysts are 
generally known. See e.g., U.S. Pat. No. 5,393,343 at Columns 3-4. 
An exemplary acrylic comb polymer, preferably one that is imidized, that is 
suitable for use as comb polymer in the present invention comprises a 
carbon containing backbone to which is attached groups shown by the 
following structures (I) and (II) and optionally structures (III) and 
(IV): 
##STR1## 
wherein each R independently represents a hydrogen atom or a methyl group 
(--CH.sub.3) group; A represents hydrogen atom, a C.sub.1 -C.sub.10 alkyl 
group, R' or an alkali or alkaline earth metal cation, an alkanolamine, or 
a mixture thereof; R' represents a hydrogen atom or a C.sub.2 -C.sub.10 
oxyalkylene group represented by (AO).sub.n R" in which O represents an 
oxygen atom, A represents a C.sub.2 -C.sub.10 alkylene group, R" 
represents a C.sub.1 -C.sub.10 alkyl and n represents an integer of from 
1-200, or mixtures thereof; and a, b, c, and d are numerical values 
representing molar percentage of the polymer's structure such that a is a 
value of about 50-70; the sum of c plus d is at least 2 to a value of 
(100-a) and is preferably from 3 to 10; and b is not more than 
[100-(a+c+d)]. 
In further exemplary imidized acrylic polymers, A is a hydrogen atom, an 
alkali or alkaline earth metal cation; R' is at least from 50-90 weight 
percent of the polymer and comprises polyoxyethylene or polyoxypropylene 
units or mixtures thereof. Further, a may have a numerical value of from 
60-70, and the sum of c and d is a numerical value of at least 3 
(preferably at least 5) to the value of (100-a). 
Further exemplary comb polymers of the invention can be obtained by 
polymerization of ethylenically-unsaturated carboxylic acids to form the 
backbone, and grafting or otherwise attaching to the backbone a number of 
other non-ionic pendant groups. The backbone may comprise carboxylic acid 
grafting sites to which are covalently attached air-detraining functional 
side chains. The carbon backbone may optionally contain intervening atoms 
like oxygen (i.e., ether linkage). Suitable grafting sites include free 
carboxylic acid (or salt thereof) groups. Carbon backbones may be made by 
polymerization of ethylenically-unsaturated monomers, preferably 
ethylenically-unsaturated carboxylic acids (e.g., allyl carboxylic acids) 
such as acrylic, methacrylic, maleic, fumaric, citraconic, itaconic, 
(meth)allylsulfonic, vinyl sulfonic, sulfoethyl(meth)acrylic, 
2-(meth)acrylamido 2-methylpropane sulfonic, mesaconic, or dicarboxylic 
acid half-esters. Preferred polycarboxylic acid carbon backbones are, 
e.g., polyacrylic or polymethacrylic acid. 5- to 200-mers are preferred, 
more preferably 5- to 150-mers, and 5- to 100-mers particularly preferred. 
Preferably about 5% or more of the carboxylic acid groups on the 
polycarboxylic acid backbone remain unesterified, more preferably about 
10% or more. 
Exemplary non-ionic pendant groups may comprise air detraining functional 
side chains which function chemically to stabilize entrained air quality 
and level in the cement or mortar, and are covalently attached to the 
grafting sites of the carbon backbone. (These pendant groups are not the 
same as the emulsified antifoaming agents being claimed herein). The side 
chains may comprise polyoxyalkylene groups of the general formula: 
EQU R.sup.4 --(OA.sup.2).sub.x --Q-- 
wherein Q=O or NH; 
A.sup.2 =C.sub.1 -C.sub.10 alkylene; 
x=1 to 200; and 
R.sup.4 =C.sub.1 -C.sub.10 alkyl. 
The term alkylene is meant herein to encompass linear or branched alkylene 
groups, and also include (where structurally possible) arylene and 
arylalkylene groups. In preferred air detraining functional side chains, 
A.sup.2 =C.sub.2 -C.sub.5 alkylene; more preferably, the OA.sup.2 groups 
are a mixture of ethylene oxide ("EO") and propylene oxide ("PO"). Air 
detraining performance appears to be particularly good when the weight 
ratio of EO/PO in the air detraining functional side chain is from about 
3:1 to 0.3:1, more preferably from about 1.5:1 to 0.6:1. Q is preferably 
O, and x is preferably 1 to 100. R.sup.4 is advantageously butyl, 
preferably a n-butyl group. It is believed that a range of polyoxyalkylene 
alcohols available from Huntsman Chemical Corporation (Houston, Tex.) 
under the tradename JEFFOX will function suitable when incorporated as air 
detraining functional side chains in the comb polymers of the invention, 
e.g., JEFFOX WL5000 and WL660. These polyoxyalkylene alcohols have number 
average molecular weights of about 3500 and 1850, respectively, and have 
the formula (C.sub.4 H.sub.9)(OA.sup.2).sub.x OH, where OA.sup.2 is a 
mixture of EO and PO, and the EO/PO weight ratio is .apprxeq.1:1. 
Other exemplary polyoxyalkylene amines which can be grafted onto/attached 
to the carbon backbone of the comb polymers herein may have the general 
formula: 
EQU R.sup.5 --O--(A.sup.3 O).sub.y --(A.sup.3).sub.p --NH.sub.2 
wherein A.sup.3 =C.sub.1 -C.sub.10 alkylene; 
y=1 to 200; 
p=1 to 50; and 
R.sup.5 =C.sub.1 -C.sub.10 alkyl. 
Such polyoxyalkylene amines may be grafted or attached to the carbon 
backbone by an amide and/or imide linkage, in which case the attached 
group would have the formula R.sup.5 --O--(A.sup.3 O).sub.y 
--(A.sup.3).sub.p --N=(note that the "=" sign is meant to signify two 
covalent bonds to other atoms, for example, to two carbonyl carbons on the 
backbone, i.e., imide linkage, or to a hydrogen atom and a carbonyl carbon 
on the backbone.) In preferred polyoxyalkylene amines, A.sup.3 =C.sub.2 
-C.sub.5 alkylene; more preferably, the A.sup.3 O groups are a mixture of 
EO and PO. An EO/PO weight ratio of about 7:1 to 0.5:1 has been found 
suitable. y is preferably in the range of 1 to 100. p is preferably in the 
range of 1 to 5, more preferably 1 to 2. R.sup.5 is preferably methyl 
(CH.sub.3 --). For example, polyoxyalkylene amines available from Huntsman 
Chemical Corporation (Houston, Tex.) under the tradename JEFFAMINE have 
been found suitable in the invention, e.g., JEFFAMINE M1000 and M2070, 
having number average molecular weights corresponding to their respective 
product numbers. The JEFFAMINEs have the formula CH.sub.3 O (A.sup.3 
O).sub.y CH.sub.2 CH(CH.sub.3)NH.sub.2, where A.sup.3 O is a mixture of EO 
and PO. 
The mole ratio of the acrylic acid monomer in the polyacrylic acid to a) 
polyoxyalkylene amine and b) polyoxyalkylene alcohol can be generally 
about 2:1 to 9:1, and the weight ratio of a) to b) is generally about 20:1 
to 2:1. It can easily be seen that by varying the amount of the 
polyoxyalkylene alcohol side chains grafted onto the backbone, exemplary 
comb polymers can be made in accordance with the invention which will 
produce corresponding variance in entrained air in the cementitious mix. 
One preferred comb polymer comprises polyacrylic acid ("PAA") to which has 
been grafted a) polyoxyalkylene amines of the formula CH.sub.3 O (A.sup.3 
O).sub.y CH.sub.2 CH(CH.sub.3)NH.sub.2, where A.sup.3 O is a mixture of EO 
and PO and the EO/PO weight ratio is from about 5:1 to 0.5:1 and b) 
polyoxyalkylene alcohols of the formula (C.sub.4 H.sub.9)(OA.sup.2).sub.x 
OH, where OA.sup.2 is a mixture of EO and PO and the EO/PO weight ratio is 
.apprxeq.1:1. 
Further exemplary comb polymers of the invention may include polymers 
having the formula 
##STR2## 
wherein each R.sup.1 independently represents a hydrogen atom or a C.sub.1 
-C.sub.5 alkyl group; A represents a mixture of Z and R.sup.2 ; Z 
represents hydrogen atom, monovalent or divalent metal cation, ammonium 
group or organic amine group; R.sup.2 represents an air detraining 
polyoxyalkylene group represented by (AO).sub.n R.sup.3 in which O 
represents an oxygen atom, A represents a C.sub.1 -C.sub.10 alkylene 
group, R.sup.3 represents a C.sub.1 -C.sub.10 alkyl group and n represents 
an integer of from 1-200, or mixtures thereof; R.sup.6 represents a 
polyoxyalkylene group represented by (AO).sub.n R.sup.3 ; and a, b, c and 
d are numerical values representing molar percentage of the polymer's 
structure such that a is a value of about 1 to 99; the sum of c+d is a 
value of 0 to the numerical value of (100-a); and b is a remainder value 
of [100-(a+c+d)]. 
a is preferably from about 30 to 99, more preferably from 50 to 99. In the 
R.sup.2 group, A preferably represents a C.sub.2 -C.sub.5 alkylene group, 
R.sup.3 represents a C.sub.1 -C.sub.4 alkyl group, and n represents an 
integer of from 1-100. More preferably, the AO groups are a mixture of EO 
and PO. Air detraining performance appears to be particularly good when 
the weight ratio of EO/PO is from about 3:1 to 0.3:1, more preferably from 
about 1.5:1 to 0.6:1. R.sup.4 is advantageously butyl, preferably a 
n-butyl group. 
R.sup.6 represents a polyoxyalkylene group represented by (AO).sub.n 
R.sup.3, and is advantageously R.sup.5 --O--(A.sup.3 O).sub.y 
--(A.sup.3).sub.p --, wherein A.sup.3 =C.sub.1 -C.sub.10 alkylene; y=1 to 
200; p=1 to 50; and R.sup.5 =C.sub.1 -C.sub.10 alkyl. Preferably, A.sup.3 
=C.sub.2 -C.sub.5 alkylene; more preferably, the A.sup.3 O groups are a 
mixture of EO and PO. An EO/PO weight ratio of about 7:1 to 0.5:1 has been 
found suitable. y is preferably in the range of 1 to 100. p is preferably 
in the range of 1 to 5, more preferably 1 to 2. R.sup.5 is preferably 
methyl (CH.sub.3 --). In a particularly preferred embodiment, a) R.sup.6 
is of the formula CH.sub.3 O A.sup.3 O).sub.y CH.sub.2 CH(CH.sub.3)--, 
where A.sup.3 O is a mixture of EO and PO, and the EO/PO weight ratio is 
from about 5:1 to 0.5:1, and b) R.sup.2 is of the (C.sub.4 
H.sub.9)(OA.sup.2).sub.x O--, where OA.sup.2 is a mixture of EO and PO and 
the EO/PO weight ratio is .apprxeq.1:1. 
The exemplary comb polymer may be made by grafting a polyoxyalkylene amine 
onto a polycarboxylic acid backbone (amidization/imidization reaction), 
then grafting onto the polycarboxylic acid backbone an air detraining 
polyoxyalkylene alcohol (via esterification reaction). It is believed that 
the alcohol may also be grafted onto the backbone before grafting the 
amine onto the backbone. The reactions are carried out in an oxygen-free 
atmosphere, in a reaction vessel having a condenser for facilitating water 
removal, e.g., a jacketed-coiled condenser fitted with a Dean-Stark trap. 
(During the course of the reactions, water (a reaction by-product) is 
removed to drive the reaction to completion.) In the 
amidization/imidization step, the reactants which are contacted with each 
other and heated to 100.degree. C. to about 185.degree. C. for about 1 to 
8 hours, preferably about 1.5 to 2.5 hours, or until the 
amidization/imidization is complete. (Again, reference is made to U.S. 
Pat. No. 5,393,343, the entire disclosure of which is incorporated herein 
by reference for further details of the reaction.) For the esterification 
reaction, a catalyst is added to catalyze the esterification of the 
polyoxyalkylene alcohol to the graft polymer. Any agent which will 
catalyze ester formation may be used (i.e., dehydrating agents, defined 
herein as those which facilitate the formation of water in chemical 
reactions; such as naphthalene sulfonic acid, carbodiimide, or p-toluene 
sulfonic acid), with p-toluene sulfonic acid preferred. The temperature is 
maintained at 100.degree. C. to about 185.degree. C. for about 1 to 8 
hours, preferably about 1.5 to 2.5 hours, or until the esterification is 
complete. Water by-product is removed as above. The reaction vessel is 
cooled, the reaction product is neutralized and the total solids of the 
mixture are adjusted with solvent if desired or necessary for addition to 
a cement composition in a desired dosage. Other methods of preparation may 
be used as long as the resultant polymer has the characteristics described 
herein. For example, certain comb polymers (containing EO/PO groups) of 
the type obtained by polymerization of ethylenically-polymerizable 
carboxylic acids and ethylenically-polymerizable polyoxyalkylenes, as 
exemplified by U.S. Pat. Nos. 4,471,100 and 4,946,904, the entire 
disclosures of which are incorporated herein by reference, comprise a 
carbon backbone and grafting sites (carboxylic acid groups). It is 
intended that air detraining functional side chains as described herein 
may be esterified to the free carboxylic acid groups of these comb 
polymers containing pendant polyoxyalkylene groups to impart the benefits 
detailed herein. Such resulting comb polymers are intended to be within 
the scope of our invention. 
Further exemplary comb polymers suitable for use in the present invention 
comprise a copolymer of a polyoxyalkylene derivative as represented by the 
following formula (1) and maleic anhydride, a hydrolyzed product of the 
copolymer, or a salt of the hydrolyzed product; 
##STR3## 
wherein "Z" represents a residue of a compound having from 2 to 8 hydroxy 
groups; "AO" represents an oxyalkylene group having from 2 to 18 carbon 
atoms; "X" represents an unsaturated hydrocarbon group having from 2 to 5 
carbon atoms; "R" represents a hydrocarbon group having from 1 to 40 
carbon atoms; "a" represents 1 to 1,000; "l" represents 1 to 7, "m" 
represents 0 to 2; and "n" represents 1 to 7; "l"+"m"+"n"=2 to 8, 
"m"/("l"+"n") is less than or equal to 1/2, and "al"+"bm"+"cn" is equal to 
or greater than 1. The copolymer shown above is taught in U.S. Pat. No. 
4,946,904, issued to Akimoto et al. (and assigned to NOF), which patent is 
incorporated by reference as if fully set forth herein. 
Another exemplary comb polymer suitable for use in the present invention is 
disclosed in U.S. Pat. No. 5,369,198, owned by Chemie Linz Gessellshaft 
m.b.H., incorporated herein by reference. Such comb polymers are composed 
of the following structural elements: 
##STR4## 
whereby M represents H or a cation such as alkaline or alkaline-earth 
metal, an ammonium group, or the residue of an organic amino group; 
R.sup.1 represents C.sub.1 to C.sub.20 alkyl, C.sub.5 to C.sub.8 
cycloalkyl or aryl group residue; R.sup.2 represents H, C.sub.1 to 
C.sub.20 alkyl or hydroxyalkyl, C.sub.5 to C.sub.8 cycloalkyl or aryl 
group residue in which 1 or more H atoms can be substituted by the 
structural elements --COOM, --SO.sub.3 M and/or PO.sub.3 M.sub.2, as well 
as structural units of the General Formula (C.sub.m H.sub.m H.sub.2m 
O).sub.n R.sup.1, which optionally can be repeated; R.sup.3 represents H, 
a methyl or methylene group which can be substituted if necessary and 
which forms a 5 to 8-member ring or an indene ring which includes R.sup.5 
; R.sup.4 represents H, a methyl or ethyl group; R.sup.5 represents H, 
C.sub.1 -C.sub.20 alkyl, C.sub.5 -C.sub.8 cycloalkyl or aryl group 
residue, an alkoxy carbonyl group, an alkoxy group, an alkyl or aryl 
carboxylate group, a carboxylate group, a hydroxyalkoxy carbonyl group; m 
represents a whole number from 2 to 4; and n represents a whole number 
from 0-100, preferably from 1-20. Methods for making the aforementioned 
copolymer are provided in U.S. Pat. No. 5,369,198, incorporated herein by 
reference. 
Another exemplary comb polymer suitable for use in the present invention 
comprises water-soluble linear copolymers of N-vinylamides with monomeric 
addition products of amines, amino acids, amino groups containing aromatic 
sulfonic acids, amino alcohols of maleic anhydride as well as maleic 
esters of polyoxyalkyleneglycols or their monoethers. One structural unit 
is represented by Formula (A) or by Formula (B); the other partial 
structure unit being represented by Formula (C): 
##STR5## 
wherein R.sup.1 and R.sup.2, which may be the same or different, each 
represent hydrogen, a C.sub.1 -C.sub.20 alkyl residue which may optionally 
include alkali metal carboxylate or alkaline earth metal carboxylate 
groups, an aromatic group, an aliphatic or cycloaliphatic residue which 
may optionally include sulfonic acid groups or alkali metal sulfonate or 
alkaline earth metal sulfonate groups, a hydroxyalkyl group, preferably a 
hydroxy ethyl- or hydroxypropyl group, or may together with the nitrogen 
atom to which they are bound, form a morpholine ring; M represents a 
hydrogen ion, a monovalent or divalent metal ion or a substituted ammonium 
group; R represents a hydrogen atom or an alkyl group having 1 to 4 carbon 
atoms; p, q, and r are integers; a represents an integer ranging from 1 to 
100; R.sup.3 and R.sup.4 which may be the same or different, each 
represent hydrogen, a C.sub.1 to C.sub.12 -alkyl residue, a phenyl 
residue, or may together form a di-, tri-, or tetramethylene group, which 
form with the inclusion of the residue of the formula: 
##STR6## 
a five, six, or seven membered ring; R.sup.5 and R.sup.6 which may be the 
same or different, each represent hydrogen, a C.sub.1 to C.sub.12 -alkyl 
residue or phenyl residue; and X represents hydrogen, a C.sub.1 to C.sub.4 
-alkyl residue, a carboxylic acid group, or an alkali metal carboxylate 
group. Such copolymer is known and taught in U.S. Pat. No. 5,100,984 
issued to Burge et al., and assigned to Sika AG, which patent is 
incorporated fully by reference as if set forth herein. 
A preferred antifoaming agent of the present invention has the formula 
(PO)(O--R).sub.3 wherein R is a C.sub.2 -C.sub.20 alkyl group. More 
preferably, R is a C.sub.3 -C.sub.6 alkyl group. A most preferred 
antifoaming agent is tri-butyl phosphate (e.g., tri-n-butyl phosphate), 
which is a hydrophobic oily liquid at ambient temperature. It is believed 
that other exemplary antifoaming agents suitable for use in the invention 
include phosphate esters (other than tri-butyl phosphate); alkyl esters 
(e.g., dibutyl phosphate); borate esters; silicone derivatives (e.g., 
polyalkyl siloxanes); and a polyoxyalkylene having defoaming properties, 
such as EO/PO type defoamers, especially ones rich with PO groups. An 
exemplary EO/PO defoamer is available from BASF under the tradename of 
PLURONIC 25-R2 and is believed to comprise an EO/PO block copolymer. It is 
believed that having an antifoaming agent emulsified in an aqueous 
solution is preferable when compared against prior art components in which 
the antifoaming agent is merely grafted onto a comb polymer or present as 
a non-homogenous disperions in the aqueous solution because the 
antifoaming agent is believed to be more readily available to control air 
in the mixture as a function of time. 
A preferred surfactant-stabilizer of the present invention comprises an 
esterified fatty acid ester of a carbohydrate such as a sugar, sorbitan, a 
monosaccharide, a disaccharide, or polysaccharide. Sorbitan monooleate is 
most preferred, and is commercially available from ICI Specialty Chemicals 
under the tradename "SPAN." Another preferred surfactant-stabilizer of the 
invention comprises an alcohol having a chain length of C.sub.2 -C.sub.20, 
and more preferably C.sub.16 -C.sub.18, with an EO/PO ratio of less than 
1. A suitable surfactant of this ethoxylated/propylated alcohol type is 
available from Huntsman under the tradename SURFONIC LF 27. 
It has been found that use of the aforementioned fatty acid ester 
surfactant-stabilizers in the invention provides an additional advantage 
in that these products slowly hydrolize in the cement environment and 
entrain very fine air bubbles in the cement compositions to which the 
inventive emulsions are added. These fine air voids provide an excellent 
defense against damage to the cement compositions caused by alternate 
freezing and thawing of the cement compositions. Moreover, the use of 
C.sub.2 -C.sub.20 EO/PO containing alcohols as surfactant-stabilizers has 
been found to further impact additional defoaming abilities to the 
emulsions of the invention, particularly during early hydration stages of 
the cement compositions to which the emulsions are added. Further, these 
EO/PO types when used with the fatty acid ester type surfactants in 
inventive emulsions and added to cement compositions containing 
conventional air-entraining agents such as gum rosins and "Vinsol" resins, 
provide set cement compositions which exhibit optimum air-void systems 
desired by the cement user. Thus the most preferred emulsions of the 
invention employ both of the aforedescribed fatty acid ester and EO/PO 
alcohol surfactant-stabilizers. 
A most preferred emulsified admixture composition of the invention thus 
comprises (a) a comb polymer of the type described above (and in U.S. Pat. 
No. 5,393,343); (b) an antifoaming agent comprising tri-butyl phosphate 
(preferably tri-n-butyl phosphate); and (c) a surfactant comprising 
sorbitan monooleate, as well as a suitable amount of dilution water (e.g., 
40-90% water by total mass). A cement composition of the invention 
comprises at least one hydratable cementitious binder, a comb polymer, an 
antifoaming agent, and a surfactant, as described above. 
An exemplary method of the invention for making the emulsified admixture 
comprises blending together the comb polymer, antifoaming agent, and 
surfactant.

The present invention can be further appreciated in view of the following 
examples, which are provided for illustrative purposes only. 
EXAMPLE 1 
(Comparative Test) 
An exemplary comb polymer having pendant oxyalkylene groups was made in 
accordance with the method described in U.S. Pat. No. 5,393,343. 1 mole of 
polyacrylic acid (mw 5000) was combined with 10 moles of a 
polyethylene-polypropylene oxide polymer (molecular weight 2000)(available 
from Huntsman under the tradename Jeffamine M-2070). The 
polyethylene-polypropylene oxide polymer used in this synthesis contained 
a primary amine group and a methyl group as the terminal groups. The 
mixture was heated and maintained at 180 degrees C, while under flowing 
nitrogen gas stream for a total of two hours. The water of solution and 
water formed as a by-product were removed. Upon cooling to 
.apprxeq.50.degree. C., the reaction product was neutralized with 40% 
(wt/wt) aqueous NaOH and total solids adjusted to 30% to 40% with 
deionized water. The resulting product was an amber viscous liquid. 
30% and 40% solutions of this comb polymer in water generated clear 
solutions. Tri-n-butyl phosphate, in the amount of 5% based on the weight 
of the polymer, was mixed into the solution, which was shaken. The 
resultant solution was cloudy. This solution was stored in a one foot long 
clear glass tube, and within a few days demonstrated phase separation 
caused by the tri-n-butyl phosphate floating to the top of the solution. 
The polymer provided a clear layer below. 
EXAMPLE 2 
(Comparative Test 2) 
Another effort to blend the tri-n-butyl phosphate and comb polymer, of the 
kind and amounts described in Example 1, was undertaken using a Waring 
blender with emulsifier blades. Thus, 5% by weight (based on polymer) of 
the tri-n-butyl phosphate was mechanically blended into about 30% and 40% 
solutions of the comb polymer. However, the resultant solutions again 
showed phase separation within one week. 
EXAMPLE 3 
(Comparative Test 3) 
Emulsification of a surfactant with the antifoaming agent, prior to 
addition of the comb polymer, did not render a stable emulsion. An 
emulsion was made using sorbitan monooleate (SPAN 80), an esterified fatty 
acid ester of sorbitan, in an amount of about 1% based on the weight of 
the comb polymer, with tri-n-butyl phosphate, added at 5% of the weight of 
the comb polymer, mixed into water. However, when the comb polymer was 
introduced into this previously made emulsion, the emulsion did not remain 
stable and phase separation was observed within one week. 
Similarly, when the comb polymer and tributyl phosphate, such as made in 
Example 1, were emulsified together first, and then the sorbitan 
monooleate was subsequently added, phase separation was observed within 
one week. 
EXAMPLE 4 
Emulsions containing 30% and 40% solutions of the comb polymers prepared as 
in Example 1, were made, each using sorbitan monooleate added at 1% based 
on the weight of the comb polymer and tri-n-butyl phosphate added at 5% of 
the weight of the comb polymer. The emulsions were prepared by emulsifying 
the comb polymer, antifoam agent and surfactant together, simultaneously 
in one step. Upon emulsification, these solutions became turbid but 
remained stable over six months of storage at temperatures of 
32-115.degree. F. No phase instability was observed. 
To test the effectiveness of one of the emulsion admixture produced in 
Example 4 above, microconcrete mortar tests were performed. Three samples 
were tested. The first sample (control) comprised a solution containing 
only the comb polymer (0.10% s/s). The second sample, for comparative 
purposes, comprised a comb polymer having a defoamer that was coupled by 
an ion pairing to the polymer (essentially a comb polymer similar to the 
one described in Example 1 above which was formulated using 3% by weight 
Jeffamine M-2005 defoamer available from Huntsman). The third sample (comb 
polymer, tri-butyl phosphate, and surfactant (sorbitan monooleate) was an 
emulsion as described in Example 4 above. 
The three samples were admixed into a mixture of cement, sand, and water 
having a water/cement ratio of 0.42 and a sand/cement weight ratio of 3. 
Sample 1 was added into the mixture at 0.10% s/s (based on weight of the 
cement); while each of samples 2 and 3 (each having additional defoamer) 
were added at about 0.11% s/s (based on the weight of cement). The samples 
were then mixed for 5 minutes initially, and then one minute prior to 
measurements of slump and air content taken at 9, 18, 30, 45, and 60 
minutes thereafter. Slump was measured in accordance with Japanese 
Standard JIS A-1173, and air content was measured in accordance with ASTM 
C 185 (1995). Results are provided in the Table 1 below. 
TABLE 1 
__________________________________________________________________________ 
Admixture Slump (cm.) Air Cup (%) 
Time set 
minutes: 9 18 30 
45 
60 9 18 
30 45 
60 
min. 
__________________________________________________________________________ 
1 comb only 
9.0 
8.6 
6.5 
5.0 
4.3 
9.2 
8.4 
7.9 
7.3 
7.1 
218 
2 comb/defoam 
9.0 
8.1 
6.0 
4.8 
3.8 
5.3 
5.3 
5.4 
5.5 
5.5 
225 
3 comb & tbp & 
9.3 
8.6 
5.8 
4.8 
4.1 
4.8 
4.4 
4.8 
4.2 
4.3 
227 
SPAN 
__________________________________________________________________________ 
The results demonstrated that sample 3, the emulsion admixture of the 
invention, eliminated a significant amount of air when compared to the 
control sample 1, and was as effective as sample 2 which was formulated 
with a defoamer (Jeffamine M-2005 which is rich in PO groups). 
The foregoing examples are provided for illustration only and are not 
intended to limit the scope of the invention, as claimed. 
EXAMPLE 5 
An emulsion as described in Example 4 is prepared except that in addition 
to the comb polymer, sorbitan monooleate and tri-n-butyl phosphate 
ingredients, 1% (based upon the weight of the comb polymer) of a C.sub.16 
-C.sub.18 ethoxylated/propylated alcohol having an EO/PO ratio of less 
than 1 (e.g., such as avilable under the tradename Surfonic LF27) is 
included in the simultaneous emulsification step. The emulsion will 
exhibit stability similar to that of the emulsion of Example 4, and 
further hydrated cement compositions containing such will exhibit desired 
enhanced air void systems rendering them resistant to freeze-thaw damage.