U.S. patent application number 13/455664 was filed with the patent office on 2012-11-22 for defoamers for hydratable cementitious compositions.
Invention is credited to Lawrence L. Kuo.
Application Number | 20120291676 13/455664 |
Document ID | / |
Family ID | 45004286 |
Filed Date | 2012-11-22 |
United States Patent
Application |
20120291676 |
Kind Code |
A1 |
Kuo; Lawrence L. |
November 22, 2012 |
DEFOAMERS FOR HYDRATABLE CEMENTITIOUS COMPOSITIONS
Abstract
The present invention discloses additive compositions,
cementitious compositions, and methods for controlling air in
cementitious compositions, wherein a polyalkoxylated polyalkylene
polyamine defoamer is deployed in combination with one or more
air-entraining agents, such as higher alkanolamines, water-reducing
agents including oxyalkylene-containing superplasticizers, or other
air entraining agents.
Inventors: |
Kuo; Lawrence L.; (Acton,
MA) |
Family ID: |
45004286 |
Appl. No.: |
13/455664 |
Filed: |
April 25, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12786881 |
May 25, 2010 |
8187376 |
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13455664 |
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Current U.S.
Class: |
106/808 |
Current CPC
Class: |
C04B 28/02 20130101;
C04B 40/0039 20130101; C04B 2103/50 20130101; C04B 40/0039
20130101; C04B 2103/304 20130101; C04B 2103/50 20130101; C04B
40/0039 20130101; C04B 24/121 20130101; C04B 24/122 20130101; C04B
24/18 20130101; C04B 24/223 20130101; C04B 24/226 20130101; C04B
24/2647 20130101; C04B 24/32 20130101; C04B 28/02 20130101; C04B
24/121 20130101; C04B 24/122 20130101; C04B 24/18 20130101; C04B
24/223 20130101; C04B 24/226 20130101; C04B 24/2647 20130101; C04B
24/32 20130101; C04B 2103/50 20130101; C04B 24/121 20130101 |
Class at
Publication: |
106/808 |
International
Class: |
C04B 16/00 20060101
C04B016/00 |
Claims
1-21. (canceled)
22. A method for controlling air in hydratable cementitious
compositions, comprising: introducing to a cementitous binder (A)
at least one agent operative to entrain air in a hydratable
cementitious composition, said at least one agent comprising a
higher trialkanolamine, a lignosulfonate, a naphthalene sulfonate,
a melamine sulfonate, an oxyalkylene-containing superplasticizer,
an oxyalkylene-containing shrinkage reducing agent, or mixture
thereof; (B) a polypropoxylated polyalkylene polyamine defoamer
formed by alkoxylating a polyalkylene polyamine with ethylene
oxide, propylene oxide, or mixture thereof, wherein the amount of
ethylene oxide groups is in the range of 0%-40% based on total
weight of polyethers, and the amount of polypropylene oxide groups
is in the range of 60%-100% based on total weight of polyethers,
the molar ratio of propylene oxide to ethylene oxide being greater
than 1, said polypropoxylated polyalkylene polyamine defoamer
having a structure represented by Formula (1) ##STR00004## or salt
thereof, or combination of said defoamer and salt thereof, wherein
each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and
R.sup.7 independently represents a hydrogen, C.sub.1-C.sub.4 alkyl
group, --CH.sub.2--OH, or -(AO).sub.x--R.sup.8, wherein at least
one of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and
R.sup.7 represents -(AO).sub.x--R.sup.8 and wherein AO represents
propylene oxide ("PO") or a mixture of PO and ethylene oxide ("EO")
wherein the molar ratio of PO to EO is at least 100:0 to 100:90;
"x" represents an integer of 4 to 100; and R.sup.8 represents
hydrogen or an alkyl group; "n" represents an integer of 0 to 100;
and wherein, if "n" is 0 then the amount of EO is less than 10% by
weight based on total weight of said polypropoxylated polyalkylene
polyamine defoamer; and (C) The ratio of component A to component B
is in the range of 5 to 100 by dry weight.
23. The composition of claim 22 wherein said polyalkylene polyamine
is selected from the group consisting of ethylene diamine,
diethylene triamine, triethylene tetramine, tetraethylene
pentamine, pentaethylene hexamine, propylene diamine, dipropylene
triamine, tripropylene tetramine, tetrapropylene pentamine,
pentapropylene hexamine, N,N-dimethylethylene diamine,
N,N'-dimethylethylene diamine, N,N-dimethylpropylene diamine,
N,N'-dimethylpropylene diamine, N,N-diethylethylene diamine,
N,N'-diethylethylene diamine, N,N-diethylpropylene diamine,
N,N'-diethylpropylene diamine.
24. The composition of claim 22 wherein said polyalkylene polyamine
is ethylene diamine, diethylene triamine, triethylene tetramine, or
mixture thereof.
25. The composition of claim 22 wherein said polyalkylene polyamine
is diethylene triamine.
26. The composition of claim 22 wherein "x" is an integer of 20 to
80.
27. The composition of claim 22 wherein "x" is an integer of 35 to
60.
28. The composition of claim 22 wherein said polyalkoxylated
polyalkylene polyamine defoamer of component B has a number-average
molecular weight of 500-7,000.
29. The composition of claim 22 wherein said polyalkoxylated
polyalkylene polyamine defoamer of component B has a number-average
molecular weight of 1,000-5,000.
30. The composition of claim 22 wherein said polyalkoxylated
polyalkylene polyamine defoamer of component B has a number-average
molecular weight of 2,000-3,500.
31. The composition of claim 22 wherein the ratio of component A to
component B is in the range of 14 to 70 by percentage weight based
on total weight of said composition for controlling air.
32. The composition of claim 22 wherein the ratio of component A to
component B is in the range of 20 to 50 by percentage weight based
on total weight of said composition for controlling air.
33. The composition of claim 22 wherein said polyalkoxylated
polyalkylene polyamine is neutralized with an acid.
Description
[0001] This application is a divisional based on Ser. No.
12/786,881, allowed Feb. 29, 2012.
FIELD OF THE INVENTION
[0002] This invention relates to air management in hydratable
cementitious materials such as concrete, and more particularly to
the use of a polyalkoxylated polyalkylene polyamine defoamer in
combination with one or more air-entraining agents for controlling
air in cementitious compositions.
BACKGROUND OF THE INVENTION
[0003] A certain amount of entrained air is necessary for improving
the freeze-thaw durability of concrete, which is a brittle
material. However, the nature and extent of air entrainment must be
carefully controlled because excessively large or unevenly spaced
air voids within the concrete can lead to loss of freeze-thaw
durability and compressive strength. Air entraining agents such as
rosins and anionic surfactants are commonly used to control the
size and spacing of air voids within the cementitious mix.
[0004] In European Patent EP 0 415 799 B1 (owned by the common
assignee hereof), Gartner et al. taught that additions to
cementitious compositions of a higher alkanolamine, such as
triisopropanolamine ("TIPA"), enhanced late strength (e.g., at 28
days) but also increased the amount of air entrained in the
cementitious composition. Analysis of various cement samples
revealed an increase in air entrainment of about two percent when
compared to cement that did not contain TIPA. Gartner et al.
suggested using air-detraining nonionic surfactants, which included
phosphates (e.g., tributylphosphate), phthalates (e.g.,
diisodecylphthalate), and polyoxypropylene-polyoxyethylene block
copolymers. See EP 0 415 799 B1 at Page 6, lines 40-53.
[0005] In U.S. Pat. No. 5,156,679 (owned by the common assignee
hereof), Gartner et al. taught the use of water-soluble alkylated
alkanolamine salts for detraining air in concrete. These materials
included N-alkylalkanolamine and N-alkyl-hydroxylamine. When TIPA
was added to a mortar mix in the amount of 0.02% by weight as part
of the water of hydration along with 0.01% by weight of
dibutylamino-2-butanol ("DBAB") as a defoamer, the mortar mix
demonstrated a reduction in air entrainment (Col. 5, line 51-Col.
6, line 14).
[0006] When concrete is formed, it requires mixing of the various
components such as hydraulic cement, sand, gravel, water, and
possibly additives to form a substantially uniform mixture. During
mixing, air becomes entrapped in the composition, and much of this
air remains in the resultant cured composition in the form of air
voids. If air void size is small, the mix is said to be "air
entrained." In most instances, a small amount of air entrainment is
tolerated, and, in other instances, this is desirable for enhancing
durability of the concrete in terms of resisting freeze/thaw
cycles.
[0007] However, excessive air entrainment in the hydraulic cement
composition will cause the resultant structure to have lower
compressive strength than the mixture design is otherwise capable
of attaining. There is an inverse relationship between air
entrainment and compressive strength. It is generally believed that
for each volume percent of air voids (bubbles) in a concrete mass,
there exists a five percent loss of compressive strength. Hence,
management of the air void content and nature is vitally
important.
[0008] Water-reducing admixtures (including superplasticizers) are
particularly known to entrain excessive air in the concrete slurry.
The industry has attempted to correct this by using air-detraining
agents (otherwise called defoamers herein) in the concrete mix. As
with the cement grinding additives (e.g., TIPA) previously
mentioned, common admixtures include hydrophobic materials such as
nonionic surfactants with low hydrophilic-lipophilic balance (HLB),
silicone derivatives, tributylphosphate, and alkyl phthalates.
[0009] However, defoamers with high hydrophobic properties have, as
a consequence, very limited solubility in water, and are not easily
incorporated into the aqueous solutions which make up the
water-reducing admixtures. Their hydrophobic nature tends to
destabilize the aqueous product by fostering separation of the
components, and requires that the water-reducing admixture and
defoamer be stored in separate tanks and mixed immediately before
use; or, alternatively, that they be pre-mixed and constantly
stirred to prevent separation.
[0010] In U.S. Pat. Nos. 5,665,158 and 5,725,657 (owned by the
common assignee hereof), Darwin et al. disclosed the use of
oxyalkylene amine-based defoaming agents for use with
polycarboxylate superplasticizers. An alkoxypolyoxyalkylene
ammonium polymer was ionically attached to the carboxylate portion
of the comb polymer backbone to impart desired air controlling
properties to the hydratable concrete being treated.
[0011] In U.S. Pat. No. 6,139,623 (owned by the common assignee
hereof), Darwin et al. disclosed polycarboxylate superplasticizers
emulsified with antifoaming agent using a surfactant to stabilize
the emulsified superplasticizer and antifoaming agent. The
antifoaming agent could be selected from phosphate esters (e.g.,
dibutylphosphate, tributylphosphate), borate esters, silicone
derivates (e.g., polyalkyl siloxanes), and polyoxyalkylenes having
defoaming properties.
[0012] In U.S. Pat. No. 6,858,661 (owned by the common assignee
hereof), Zhang et al. disclosed a polycarboxylate water-reducer and
a tertiary amine defoamer having an average molecular weight of
100-1500 for creating a stable admixture formulation and helping to
achieve a controllable level of entrained air in the concrete
mix.
[0013] In U.S. Pat. No. 6,545,067 (owned by BASF), Buchner et al.
disclosed mixtures of polycarboxylate superplasticizer and
butoxylated polyalkylene polyamine as a defoamer for reducing the
air pore content of cement mixes.
[0014] In U.S. Pat. No. 6,803,396 (also owned by BASF),
Gopalkrishnan et al. disclosed mixtures of polycarboxylate
superplasticizer and air-detraining agents. The air detrainers were
based on low molecular weight block polyether polymers described as
containing ethylene oxide and propylene oxide units and described
as being initiated using reactive diamine or glycol groups.
[0015] In U.S. Pat. No. 6,569,924 (owned by MBT Holding AG), Shendy
et al. disclosed the use of polycarboxylate dispersants, a
water-insoluble defoamer, and a solubilizing agents for
solubilizing the water-insoluble defoamer. Such solubilizing agents
functioned by increasing the amount of oil component within the
aqueous phase. A similar approach was taken in U.S. Pat. No.
6,875,801 wherein Shendy et al. described using amine solubilizing
agents for stabilizing water-insoluble defoamers.
[0016] Regardless of whether the defoamer is grafted onto a polymer
dispersant or emulsified or rendered more water-soluble within the
additive composition, the present inventor believes that a critical
problem still remains with avoiding phase separation within the
water-based additive formulation while retaining the efficacy of
the defoamer to detrain air within the cementitious mixture being
treated.
[0017] Accordingly, an improved defoamer additive composition is
needed for improving the stability of air-entraining additives used
in cement or concrete mixes without curtailing the effectiveness of
the defoamer as an air-detraining agent. The present inventor
believes that a new class of defoamers for use with air-entraining
agents, such as higher trialkanolamines and water-reducing agents,
is needed for controlling air content in cementitious materials,
and also for providing different degrees of defoaming power, yet
with increasing water compatability that provides resistance to
phase separation.
SUMMARY OF THE INVENTION
[0018] In surmounting the disadvantages of the prior art, the
present invention provides a novel and inventive additive
composition for controlling air in hydratable cementitious
compositions. The term "additive" is used herein to refer to agents
added at cement plants where clinker is interground to produce
cement and also to refer to "admixtures" which are combined with
cement, water, and aggregates to produce mortar or concrete.
[0019] The present invention involves the use of a defoamer that
can be used alone with conventional air-entraining agents (e.g.,
higher alkanolamines such as TIPA), water-reducing agents such as
oxyalkylene-containing superplasticizers), or in combination with
existing defoamers (e.g., tributyl-phosphate).
[0020] Thus, an exemplary additive composition of the present
invention for controlling air in hydratable cementitious
compositions comprises:
[0021] (A) at least one agent operative to entrain air in a
hydratable cementitious composition, said at least one agent
comprising a higher trialkanolamine, a lignosulfonate, a
naphthalene sulfonate, a melamine sulfonate, an
oxyalkylene-containing superplasticizer, an oxyalkylene-containing
shrinkage reducing agent, or mixture thereof;
[0022] (B) a polyalkoxylated polyalkylene polyamine defoamer having
a structure represented by Formula (1)
##STR00001##
or salt thereof, or combination of said defoamer and salt thereof,
wherein each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5,
R.sup.6, and R.sup.7 independently represents a hydrogen,
C.sub.1-C.sub.4 alkyl group, --CH.sub.2--OH, or
-(AO).sub.x--R.sup.8 wherein AO represents propylene oxide ("PO")
or a mixture of PO and ethylene oxide ("EO") wherein the molar
ratio of PO to EO is at least 100:0 to 100:90; "x" represents an
integer of 0 to 100; and R.sup.8 represents hydrogen or an alkyl
group; "n" represents an integer of 0 to 100; and
[0023] wherein, if "n" is 0 then the amount of EO is less than 10%
by weight based on total weight of said polyalkoxylated
polyalkylene polyamine defoamer; and
[0024] (C) the ratio of component A to component B is in the range
of 5 to 100 by dry weight.
[0025] An exemplary cement composition of the invention comprises a
hydratable cementitious binder and the foregoing additive
composition, while an exemplary method of the invention comprises
combining a hydratable cementitious binder with the foregoing
additive composition.
[0026] Further advantages and features of the invention may be
described in detail hereinafter.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0027] The term "cement" as used herein includes hydratable cement
which is produced by pulverizing clinker consisting of hydraulic
calcium silicates and one or more forms of calcium sulfate (e.g.,
gypsum) as an interground additive. "Mortars" are cement pastes
formed with water and additionally including fine aggregate (e.g.,
sand), while "concretes" are mortars which additionally include
coarse aggregate (e.g., crushed stones or gravel).
[0028] The term "cementitious" as used herein refers to materials
that include or comprise cement (e.g., Portland cement) or which
otherwise function as a binder to hold together fine aggregates
(e.g., sand), coarse aggregates (e.g., crushed gravel), or mixtures
thereof. Typically, Portland cement is combined with one or more
other supplementary cementitious materials ("SCMs") and provided as
a blend. SCMs may include limestone, hydrated lime, fly ash,
granulated blast furnace slag, and silica fume, or other materials
commonly included in such cements. Cementitious materials may
therefore include one or more SCMs preferably in an amount of
0%-100%, more preferably 10%-60%, based on total dry weight of
cementitious material.
[0029] The term "hydratable" as used herein is intended to refer to
cement or cementitious materials that are hardened by chemical
interaction with water. Portland cement clinker is a partially
fused mass primarily composed of hydratable calcium silicates. The
calcium silicates are essentially a mixture of tricalcium silicate
(3CaO.SiO.sub.2 "C.sub.3S" in cement chemists notation) and
dicalcium silicate (2CaO.SiO.sub.2, "C.sub.2S") in which the former
is the dominant form, with lesser amounts of tricalcium aluminate
(3CaO.Al.sub.2O.sub.3, "C.sub.3A") and tetracalcium aluminoferrite
(4CaO.Al.sub.2O.sub.3.Fe.sub.2O.sub.3, "C.sub.4AF"). See e.g.,
Dodson, Vance H., Concrete Admixtures (Van Nostrand Reinhold, New
York N.Y. 1990), page 1.
[0030] As previously summarized, exemplary additive and cement
compositions of the invention comprise the use of at least one
agent comprising a higher trialkanolamine, lignosulfonate, a
naphthalene sulfonate, a melamine sulfonate, an
oxyalkylene-containing superplasticizer, an oxyalkylene-containing
shrinkage reducing agent, or mixture thereof. The term "additive"
shall be used herein to describe additives added at the cement
manufacturing plant and also to describe "admixtures" which are
added to cement, water, and optional aggregates used for making
cement mortars, concretes, and other cementitious materials.
Preferably, the additive compositions are aqueous liquids that may
be dispensed (e.g., pump-metered) in liquid form.
[0031] The term "higher trialkanolamine" as used herein shall refer
to tertiary amine compounds which are tri(hydroxyalkyl)amines
having at least one C.sub.3--O.sub.5 hydroxyalkyl, and, more
preferably, at least one C.sub.3-C.sub.4 hydroxyalkyl, group
therein. The remaining (if any) hydroxyalkyl groups of the tertiary
amine can be selected from C.sub.1-C.sub.2 hydroxyalkyl groups
(preferably C.sub.2 hydroxyalkyl). Examples of such compounds
include hydroxyethyl di(hydroxypropyl)amine, hydroxypropyl
di(hydroxyethyl)amine, tri(hydroxypropyl)amine, hydroxyethyl
di(hydroxy-n-butyl)amine, tri(2-hydroxybutyl)amine, hydroxybutyl
di(hydroxypropyl)amine, and the like. The preferred higher
trialkanolamines are triisopropanolamine ("TIPA"),
N,N-bis(2-hydroxyethyl)-N-(2-hydroxypropyl)amine ("DEIPA"),
N,N-bis(2-hydroxypropyl)-N-(hydroxyethyl)amine ("EDIPA"), and
tri(2-hydroxybutyl)amine. Mixtures of such higher trialkanolamines
can be used, and any of these or a combination of these can be used
with one or more of triethanolamine (TEA), diethanolamine (DEA),
monoethanolamine, or mixtures thereof. When used as a grinding
additive for Portland cement or blended cement, the higher
trialkanolamines can be added in an amount up to 2%, preferably up
to 0.1%, and most preferably between 0.005%-0.03% based on weight
of the cement. In particular, TIPA is known for use as a late
strength enhancer.
[0032] The terms "lignosulfonate," "naphthalene sulfonate,"
"melamine sulfonate," and "oxyalkylene-containing superplasticizer"
are used herein to refer to water-reducing agents ("WRA") known to
entrain air. A "lignosulfonate" WRA includes alkali metal or
alkaline earth salts of lignosulfonic acid, such as calcium
lignosulfonate, which is a commonly-used WRA. A "naphthalene
sulfonate" WRA includes an alkali metal salt of a sulfonated
naphthalene-formaldehyde condensate; while a "melamine sulfonate"
WRA includes an alkali metal salt of a sulfonated
melamine-formaldehyde condensate.
[0033] References to compounds in their salt form may be understood
to include reference to their acid form, and vice-versa, because it
may be the case that both acid and salt forms can co-exist within
the aqueous environment. Similarly, it may also be understood that
reference to compounds in their amine form may be understood to
include reference to their ammonium form, and vice-versa.
[0034] The term "oxyalkylene-containing superplasticizer" will
refer to water-reducing agents, typically comb polymers comprised
of polycarboxylic acid or partial esters to which are attached
pendant polyoxyalkylene groups. Such oxyalkylene groups include
ethylene oxide (EO), propylene oxide (PO), and butylene oxide. Such
oxyalkylene-containing superplasticizer will be any of those
customarily used in the cement and concrete industries. For
example, polymeric superplasticizers which are comb polymers having
a carbon-containing backbone to which are attached polyoxyalkylene
groups through amide, imide, ester, and/or ether linkages are
contemplated for use in the present invention. Other examples of
oxyalkylene-containing superplasticizers include copolymers of
acrylic or methacrylic acid with the reaction product of acrylic
acid or methacrylic acid with polyalkyleneglycol monomethyl ether.
A further example of oxyalkylene-containing superplasticizers
includes copolymers of acrylic acid or methacrylic acid with
polyalkoxylated alcohols with typical alcohol chain lengths of
C.sub.3 to C.sub.20.
[0035] Generally, the amount of air-entraining WRA used in the
invention which is to be added to cement compositions will be in
amounts of at least about 0.005 weight percent, and usually in the
range of 0.005 to about 5 weight percent, and preferably 0.03
weight percent to about 1 weight percent based on the total weight
of the cement or cementitious composition.
[0036] The term "oxyalkylene-containing shrinkage reducing agent"
(hereinafter oxyalkylene-containing "SRA") refers to additives
which are designed to inhibit drying shrinkage of cementitious
compositions by maintaining or increasing air void content of the
cementitious composition. Examples of oxyalkylene-containing SRAs
and SRA formulated compositions are disclosed in U.S. Pat. Nos.
5,556,460; 5,604,273; 5,618,344; 5,779,788; and 5,622,558;
5,603,760; and 6,277,191, all of which are incorporated herein by
reference. While many of the SRA compositions and formulations
described in these patent references are useful for maintaining or
controlling air content, the inventor believes that the use of the
polyalkoxylated polyalkylene polyamine defoamer of the present
invention can expand design possibilities of oxyalkylene SRAs in
that smaller, more uniform air voids can be formed.
[0037] Thus, an exemplary additive composition of the invention for
controlling air in hydratable cementitious compositions
comprises:
[0038] (A) at least one agent operative to entrain air in a
hydratable cementitious composition, said at least one agent
comprising a higher trialkanolamine, a lignosulfonate, a
naphthalene sulfonate, a melamine sulfonate, an
oxyalkylene-containing superplasticizer, an oxyalkylene-containing
shrinkage reducing agent, or mixture thereof; and
[0039] (B) a polyalkoxylated polyalkylene polyamine defoamer having
a structure represented by Formula (1)
##STR00002##
or salt thereof, or combination of said defoamer and salt thereof,
wherein each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5,
R.sup.6, and R.sup.7 independently represents a hydrogen,
C.sub.1-C.sub.4 alkyl group, --CH.sub.2--OH, or
-(AO).sub.x--R.sup.8 wherein AO represents propylene oxide ("PO")
or a mixture of PO and ethylene oxide ("EO") wherein the molar
ratio of PO to EO is at least 100:0 to 100:90; "x" represents an
integer of 0 to 100; and R.sup.8 represents hydrogen or an alkyl
group; "n" represents an integer of 0 to 100; and
[0040] wherein, if "n" is 0 then the amount of EO is less than 10%
by weight based on total weight of said polyalkoxylated
polyalkylene polyamine defoamer; and
[0041] (C) the ratio of component A to component B is in the range
of 5 to 100 by dry weight (and more preferably in the range of 14
to 70, and most preferably in the range of 20 to 50).
[0042] In preferred exemplary embodiments, the defoamer is made by
polyalkoxylation of a polyalkylene polyamine. Exemplary
polyalkylene polyamines suitable for use in the present invention
include, but are not limited to, ethylene diamine, diethylene
triamine, triethylene tetramine, tetraethylene pentamine,
pentaethylene hexamine, propylene diamine, dipropylene triamine,
tripropylene tetramine, tetrapropylene pentamine, pentapropylene
hexamine, N,N-dimethylethylene diamine, N,N'-dimethylethylene
diamine, N,N-dimethylpropylene diamine, N,N'-dimethylpropylene
diamine, N,N-diethylethylene diamine, N,N'-diethylethylene diamine,
N,N-diethylpropylene diamine, N,N'-diethylpropylene diamine. More
preferred of these polyalkylene polyamines are ethylene diamine,
diethylene triamine, triethylene tetramine, or mixtures thereof,
with the most preferred being diethylene triamine.
[0043] In further exemplary embodiments, the polyalkylene polyamine
may be alkoxylated by reacting it with ethylene oxide and propylene
oxide. In still further exemplary embodiments, the polyalkylene
polyamine may be alkoxylated by reacting it with ethylene oxide and
propylene oxide wherein the molar ratio of propylene oxide to
ethylene oxide is greater than 1. In another preferred embodiment,
the amount of ethylene oxide groups is in the range of 0%-40% based
on total weight of the polyethers, whereas the amount of
polypropylene oxide groups is in the range of 60%-100% based on
total weight of the polyethers.
[0044] In further exemplary embodiments, the polyalkoxylated
polyalkylene polyamine defoamer of component B has a number-average
molecular weight of 500-7000. More preferably, the number-average
molecular weight is 1000-5000; and most preferably the
number-average molecular weight is 2000-3500.
[0045] In further exemplary embodiments, the polyalkoxylated
polyalkylene polyamine defoamer of component B is neutralized with
an acid. The acid may be selected from formic acid, acetic acid,
propionic acid, hydrochloric acid, nitric acid, sulfuric acid, or a
mixture thereof. Preferably, the acid is formic acid or acetic
acid. An exemplary acid which may be used for neutralizing the
polyalkoxylated polyalkylene polyamine defoamer of component B may
also be an oxyalkylene-containing superplasticizer.
[0046] The present invention also provides a method for controlling
air in a cementitious composition which comprises combining a
hydratable cementitious binder, such as cement (which may include
supplemental cementitious materials), with the aforementioned
polyalkoxylated polyalkylene polyamine defoamer.
[0047] Thus, an exemplary method of the present invention
controlling air in cementitious compositions comprises combining a
hydratable cementitious composition with an additive having
[0048] (A) at least one agent operative to entrain air in a
hydratable cementitious composition, said at least one agent
comprising a higher trialkanolamine, a lignosulfonate, a
naphthalene sulfonate, a melamine sulfonate, an
oxyalkylene-containing superplasticizer, an oxyalkylene-containing
shrinkage reducing agent, or mixture thereof;
[0049] (B) a polyalkoxylated polyalkylene polyamine defoamer having
a structure represented by Formula (1)
##STR00003##
or salt thereof, or combination of said defoamer and salt thereof,
wherein each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5,
R.sup.6, and R.sup.7 independently represents a hydrogen,
C.sub.1-C.sub.4 alkyl group, --CH.sub.2--OH, or
-(AO).sub.x--R.sup.8 wherein AO represents propylene oxide ("PO")
or a mixture of PO and ethylene oxide ("EO") wherein the molar
ratio of PO to EO is at least 100:0 to 100:90; "x" represents an
integer of 0 to 100; and R.sup.8 represents hydrogen or an alkyl
group; "n" represents an integer of 0 to 100; and
[0050] wherein, if "n" is 0 then the amount of EO is less than 10%
by weight based on total weight of said polyalkoxylated
polyalkylene polyamine defoamer; and
[0051] (C) the ratio of component A to component B is in the range
of 5 to 100 by dry weight (and more preferably in the range of
14-70, and most preferably in the range of 20-50).
[0052] The present invention also pertains to cement compositions
comprising a hydratable cementitious binder and the aforementioned
polyalkoxylated polyalkylene polyamine defoamer which may be in
amine form, ammonium salt form, or simultaneously in both forms,
depending upon pH level and/or other factors.
[0053] The amount of the polyalkoxylated polyalkylene defoamer used
will depend on the amount and nature of the one or more
air-entraining agents used (Component (A)), but typically could be
in the range of 0.05-5.0% based on weight of hydratable cement in
the cementitious composition being treated.
[0054] In further exemplary methods and compositions of the
inventions, one or more conventional defoamers may be combined with
the polyalkoxylated polyalkylene polyamine in exemplary additive
compositions, cement compositions and methods of the invention.
Conventional defoamers that are contemplated for use in the present
invention include tributylphosphate. Another such defoamer is
bishydroxylpropyl tallow amine (a tertiary amine defoamer
represented by the structural formula R.sup.1NR.sup.2R.sup.3
wherein R.sup.1 is hydrophobic and represents a C.sub.8-C.sub.25
group comprising a linear or branched alkyl, alkene, alkyne,
alcohol, ester or oxyalkylene group (e.g., polyoxyalkylene)
represented by the formula R.sup.4-(AO).sub.n-- or
R.sup.4--(OA).sub.n- wherein R.sup.4 represents hydrogen or a
C.sub.1 to C.sub.25 alkyl group, A represents a C.sub.1 to C.sub.6
alkyl group and "n" is an integer of 1 to 4; and R.sup.2 and
R.sup.3 each represent a C.sub.1-C.sub.6 group comprising a
branched or linear alkyl, alkene, alkyne, alcohol, ester or
oxyalkylene group (e.g., polyoxyalkylene) represented by the
formulae R.sup.4-(AO).sub.n-- or R.sup.4(OA).sub.n- wherein R.sup.4
represents hydrogen or a C.sub.1-C.sub.25 alkyl group, A represents
a C.sub.1 to C.sub.6 alkyl group, and "n" is an integer of 1 to 4;
and wherein the average molecular weight of the tertiary amine
defoamer is 100-1500 and more preferably 200-750.
[0055] Further exemplary defoamers include oxyalkylene amines. The
general composition can be represented by structural formula
X.sub.2N(BO).sub.zR wherein X represents hydrogen, (BO).sub.zR, or
mixtures thereof; R represents hydrogen, a C.sub.1-C.sub.10 alkyl
group, or BNH.sub.2 wherein B represents a C.sub.2-C.sub.10
alkylene group; and z represents an integer from 5 to 200.
[0056] Further exemplary defoamers may also be selected from the
group consisting of a composition represented by the formula
(PO)(O--R).sub.3 wherein R is a C.sub.2-C.sub.20 alkyl group, a
borate ester, a silicone derivative, and EO/PO type defoamer. Still
further exemplary defoamers may include ceto-stearyl alcohol
ethoxylates and ceto-oleyl alcohol ethoxylates, specifically
ethoxylated and proproxylated linear primary C.sub.16-C.sub.18
alcohols.
[0057] While the invention is described herein using a limited
number of embodiments, these specific embodiments are not intended
to limit the scope of the invention as otherwise described and
claimed herein. Modification and variations from the described
embodiments exist. More specifically, the following examples are
given as a specific illustration of embodiments of the claimed
invention. It should be understood that the invention is not
limited to the specific details set forth in the examples.
Example 1
[0058] An aqueous mixture of a polycarboxylate dispersant and
polyalkoxylated polyethylene polyamine was prepared to yield a
solution wherein solids comprised 25% to 40% solution by total
weight. The polymeric dispersant comprised a backbone having
polycarboxylate groups and pendant polyethylene oxide groups.
Polyethylene polyamines having different degrees of
polypropoxylation, indicated in terms of the number of moles of
propylene oxide per mole of polyamine, are provided in Table 1
below.
TABLE-US-00001 TABLE 1 Additive Propylene oxide/ sample Polyamine
polyamine (mol/mol) 1 Ethylenediamine 40 2 Ethylenediamine 50 3
Diethylene triamine 40 4 Diethylene triamine 45 5 Diethylene
triamine 50 6 Triethylene tetramine 40
[0059] In these experiments, polycarboxylate and polypropoxylated
polyamine were mixed together at various weight ratios ranging from
20 to 50; the total concentration was 25 to 40 wt % in water. Each
of the solutions was stirred for 15 to 30 minutes at ambient
temperature and the pH of final solution ranged from 4-5. After
being stored for 60 days at ambient conditions, the resultant
solutions did not show any phase separation, indicating good
storage stability.
Example 2
[0060] In this example, the defoaming property of various
polypropoxylated polyamine additives was evaluated in a standard
mortar test for slump and air content. Ordinary Portland cement X
was used at a sand/cement/water ratio of 3/1/0.5. All tests were
carried out in the presence of polycarboxylate dispersant A and an
air-entraining agent. The dose of the dispersant was 0.13% by
weight of cement and the ratio of dispersant to additive was 33:1
by weight. The air-entraining agent is commercially available from
Grace Construction Products, Cambridge, Mass. under the trade name
DAREX.RTM. II AEA. The air content was measured in accordance with
ASTM C 185 and the workability was calculated using the
equation,
Workability=slump+(flow 1+flow 2)/2-100
Three different polypropoxylated polyamines were compared with the
control and the results are shown in Table 2.
TABLE-US-00002 TABLE 2 Workability Air content Additive (mm) (%)
None 197 19.7 1 210 10.2 3 216 11.0 6 215 11.0
As compared to the control mix without additive, the lower air
percentages for mixes using the additives clearly indicate that the
polypropoxylated polyamines functioned as effective defoamers. The
decreased air content also reflected in an increase in
workability.
Example 3
[0061] The mortar test protocol described in Example 2 was
repeated, except that ordinary Portland cement Y and
polycarboxylate dispersant B were used. Five different defoamers
were evaluated at different weight ratios to the polycarboxylate
dispersant. In addition, the change in air content was measured as
a function of time. The results are shown in Table 3.
TABLE-US-00003 TABLE 3 Air Air Air Addi- Dispersant/ Workability
Content % Content % Content % tive Additve (mm) at 9 min. at 25
min. at 40 min. 1 29 219 16.4 14.1 11.6 2 40 221 11.5 10.3 8.7 3 33
218 17.8 15.5 12.7 5 33 211 11.7 10.8 9.0 6 33 225 12.4 10.8
9.5
The results in this example indicate that the air content can be
tailored through a combination of selection of the type of
polyalkylene polyamine, degree of polypropoxylation, and its
concentration relative to the amount of dispersant.
Example 4
[0062] This example illustrates the effectiveness of the
polypropoxylated diethylene triamine as a defoamer for three
different types of polycarboxylate dispersants in concrete. When
the defoamer was used, the dispersant and defoamer were mixed
together at a weight ratio of 33:1.
[0063] Concrete mixes were fabricated using the following
proportions: Portland cement X in the amount of 611 lb/yd.sup.3,
fine aggregate in the amount of 1330 lb/yd.sup.3, coarse aggregate
in the amount of 1650 lb/yd.sup.3, and water in the amount of 278
lb/yd.sup.3. Air content was tested in accordance with ASTM
C231-97. Other concrete properties such as slump, strength and set
time were tested to confirm that the concrete was in a reasonable
range for experimental purposes. Both slump and air content were
measured at 9 minute mark and the results are summarized in Table
4.
TABLE-US-00004 TABLE 4 Polycarboxylate % added to Slump Dispersant
(type) Cement Additive (inches) Air (%) B 0.12 none 7.50 6.4 B 0.12
4 6.00 3.3 C 0.12 none 7.75 8.7 C 0.12 4 7.00 4.2 D 0.12 none 8.75
7.3 C 0.12 4 7.50 3.6
Although each polycarboxylate dispersant entrapped different amount
of air, the results in Table 4 clearly indicate that
polypropoxylated diethylene triamine effectively reduced the air
content by about 50%.
Example 5
[0064] This example demonstrates the function of polypropoxylated
diethylene triamine and polypropoxylated triethylene tetramine as
defoamer in air-entrained concrete.
[0065] The concrete test protocol was similar to that used in
Example 4, except that a conventional air-entraining agent was also
incorporated. A commercial air-entraining agent (commercially
available from Grace Construction Products, Cambridge, Mass., under
the trade name DARAVAIR.RTM. 1000) was used at 0.75 oz/cwt of
cement.
[0066] Also in this example, polycarboxylate dispersant B was
employed at the dosage of 0.11% by weight of cement and its weight
ratio to additive was fixed at 50:1. Table 5 summarizes the
results.
TABLE-US-00005 TABLE 5 Polycarboxylate % added to Slump Dispersant
(type) Cement Additive (inches) Air (%) B 0.11 none 8.75 8.8 B 0.11
3 8.00 5.8 B 0.11 5 7.75 4.9 B 0.11 6 8.00 6.2
The results in this table indicate that all three additives
exhibited an air detraining (defoaming) ability in air-entrained
concrete, and that for the same diamine, the air detraining power
also increased with increasing degree of polypropoxylation.
Example 6
[0067] The defoaming effects of polypropoxylated ethylene diamine
and polypropoxylated diethylene triamine were evaluated as a
function of time in air-entrained concrete. The test protocol of
Example 5 was used, and both slump and air content were measured at
9, 25, and 40 minute marks. An air-entraining agent, commercially
available from Grace Construction Products under the trade name
DAREX.RTM. II AEA, was used at a dosage of 0.20 oz/cwt of cement.
Aqueous solutions of polycarboxylate dispersant B and additive were
made at a weight ratio of 33:1. The results of the experiments are
tabulated in Table 6.
TABLE-US-00006 TABLE 6 Disper- sant/ Addi- Addi- Slump (inches) at
Air Content (%) at tive tive 9 min. 25 min. 40 min. 9 min. 25 min.
40 min. none 9.75 7.75 6.75 14.8 12.0 10.4 1 33 9.00 7.75 6.25 8.9
8.1 7.3 3 33 9.25 8.00 7.00 9.3 8.9 8.3
Compared to the control mix without additive, both polypropoxylated
ethylene diamine and polypropoxylated diethylene triamine clearly
demonstrated their defoaming properties over the course of the
experiments.
[0068] The foregoing example and embodiments were present for
illustrative purposes only and not intended to limit the scope of
the invention.
* * * * *