U.S. patent application number 09/840397 was filed with the patent office on 2001-12-20 for cement admixture and cement composition comprising this.
This patent application is currently assigned to Nippon Shokubai Co., Ltd.. Invention is credited to Hirata, Tsuyoshi, Mitsukawa, Hiroshi, Yamashita, Akihiko.
Application Number | 20010052308 09/840397 |
Document ID | / |
Family ID | 18639939 |
Filed Date | 2001-12-20 |
United States Patent
Application |
20010052308 |
Kind Code |
A1 |
Yamashita, Akihiko ; et
al. |
December 20, 2001 |
Cement admixture and cement composition comprising this
Abstract
The present invention provides: a cement admixture which
displays excellent cracking inhibition effect and brings about good
fluidity even if the quantity of the cement admixture as added is
small; and a cement composition comprising this cement admixture.
The cement admixture comprises a polyalkylene glycol (A) and a
polyalkylene glycol mono(meth)acrylate/unsaturated carboxylic
acid-based copolymer (B), wherein: the average molecular weight (X)
of the (A) is in the range of 400 to 10,000; the average molecular
weight (X) of the (A) and the average molecular weight (Y) of a
polyalkylene glycol chain portion of the (B) satisfy
0.9<(X/Y)<1.1; and the weight ratio of the (A) to the (B) is
in the range of (A)/(B)=0.02 to 0.3. The cement composition at
least comprises the above cement admixture, water, and cement.
Inventors: |
Yamashita, Akihiko;
(Ibaraki-shi, JP) ; Mitsukawa, Hiroshi;
(Hirakata-shi, JP) ; Hirata, Tsuyoshi; (Kobe-shi,
JP) |
Correspondence
Address: |
Robert J. Jacobson, P.A.
650 Brimhall Street South
St. Paul
MN
55116-1511
US
|
Assignee: |
Nippon Shokubai Co., Ltd.
|
Family ID: |
18639939 |
Appl. No.: |
09/840397 |
Filed: |
April 23, 2001 |
Current U.S.
Class: |
106/728 ;
106/823; 524/5 |
Current CPC
Class: |
C04B 40/0039 20130101;
C04B 2111/343 20130101; C04B 24/2647 20130101; C04B 24/32 20130101;
C04B 28/02 20130101; C04B 40/0039 20130101; C04B 24/2647
20130101 |
Class at
Publication: |
106/728 ;
106/823; 524/5 |
International
Class: |
C04B 024/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2000 |
JP |
2000-130949 |
Claims
What is claimed is:
1. A cement admixture, which comprises a polyalkylene glycol (A)
and a polyalkylene glycol mono(meth)acrylate/unsaturated carboxylic
acid-based copolymer (B), wherein: the average molecular weight (X)
of the polyalkylene glycol (A) is in the range of 400 to 10,000;
the average molecular weight (X) of the polyalkylene glycol (A) and
the average molecular weight (Y) of a polyalkylene glycol chain
portion of the copolymer (B) satisfy the following equation
(1):0.9<(X/Y)<1.1 (1);and the weight ratio of the
polyalkylene glycol (A) to the copolymer (B) is in the range of
(A)/(B)=0.02 to 0.3.
2. A cement admixture according to claim 1, wherein the
milliequivalent number of carboxyl groups in the polyalkylene
glycol mono(meth)acrylate/unsaturated carboxylic acid-based
copolymer (B) is in the range of 0.25 to 5.00 meq/g assuming all
the carboxyl groups in the copolymer (B) to be in unneutralized
forms.
3. A cement composition, which at least comprises the cement
admixture as recited in claim 1, water, and cement.
4. A cement composition, which at least comprises the cement
admixture as recited in claim 2, water, and cement.
Description
BACKGROUND ART
[0001] A. Technical Field
[0002] The present invention relates to a cement admixture and a
cement composition comprising this. More specifically, the
invention relates to: a cement admixture which is mixed into cement
mixtures, such as cement paste, mortar, and concrete, and thereby
can give the cement mixtures excellent cracking inhibition effect
and excellent fluidity; and a cement composition comprising this
admixture.
[0003] B. Backgrounds Art
[0004] In general, cement mixtures, such as cement paste, mortar,
and concrete, are used in order to construct such as civil
engineering structures and building structures. However, hitherto,
there are problems in that: according to such as outside air
temperature or humidity conditions, the volatilization of unreacted
water from the concreted cement mixtures might promote the drying
shrinkage to crack the hardened products, and the resultant cracks
cause the deterioration of the strength and watertightness of the
above structures. Furthermore, in recent years, there is a movement
to bind in duty to give a guarantee against cracks due to the
drying shrinkage. For example, a law regarding the promotion to
ensure the house quality, which intends to add cracking of concrete
to objects of a guarantee against defects, is put in effect.
Therefore, it is desired to take effective countermeasures to
suppress the drying shrinkage of the cement mixtures to thereby
prevent cracking.
[0005] As to the means to suppress the drying shrinkage of the
cement mixtures to a small one, it is effective to decrease the
quantity of water (unit water quantity) for knead-mixing of
concrete. For example, the Architectural Society of Japan
prescribes that the upper limit value of the unit water quantity in
high durable concrete should be 175 kg. Hitherto, high-performance
water-reducing agents such as salts of .beta.-naphthalenesulfonic
acid-formaldehyde condensation products are conventionally used to
satisfy this prescription.
[0006] However, in the case where the high-performance
water-reducing agents are used, there are problems in that:
chemical or physical cohesion of cement particles proceeds with the
passage of time after knead-mixing, and the fluidity is therefore
apt to decrease with the passage of time, with the result that
there occur troubles with execution of works.
[0007] On the other hand, various studies are carried out also
about shrinkage-reducing agents to suppress the drying shrinkage of
the cement mixtures to a small one. For example, JP-B-051148/1981
proposes alkylene oxide adducts to alcohols having 1 to 4 carbon
atoms, and JP-B-053214/1989 proposes ethylene oxide-propylene oxide
co-adducts to di- to octahydric alcohols, and JP-B-053215/1989
proposes alkylene oxide adducts to lower alkylamines, and
JP-A-152253/1984 proposes oligomeric polypropylene glycol, and
JP-B-006500/1994 proposes low-molecular alcohols, and Japanese
Patent No. 2825855 proposes alkylene oxide adducts to
2-ethylhexanol having 8 carbon atoms.
[0008] However, all these shrinkage-reducing agents are oligomers
or low-molecular compounds having a molecular weight of not larger
than hundreds, and therefore involve problems in that: for example,
as is also described in "The Development of Concrete Admixture and
Its Newest Technology" (1st edition, issued by CMC Co., Ltd. on
Sep. 18, 1995), these shrinkage-reducing agents need to be used in
a large standard amount of 2 to 6% of the unit cement weight,
therefore the cost of concrete increases.
Summary of the Invention
[0009] A. OBJECT OF THE INVENTION
[0010] An object of the present invention is to provide: a cement
admixture which displays excellent cracking inhibition effect and
brings about good fluidity even if the quantity of the cement
admixture as added is small; and a cement composition comprising
this cement admixture.
[0011] B. DISCLOSURE OF THE INVENTION
[0012] The present inventors diligently studied to solve the
above-mentioned problems. As a result, they have completed the
present invention by finding that: if a polyalkylene glycol having
a specific molecular weight is allowed to coexist in a specific
ratio with a polyalkylene glycol mono(meth)acrylate/unsaturated
carboxylic acid-based copolymer having a polyalkylene glycol chain
portion of which the average molecular weight is nearly equal to
that of the above-mentioned polyalkylene glycol (the difference
between these molecular weights is in a definite range), then the
resultant mixture is a cement admixture which is extremely
excellent in both properties of the drying shrinkage reducibility
and the dispersibility.
[0013] Namely, a cement admixture, according to the present
invention, comprises a polyalkylene glycol (A) and a polyalkylene
glycol mono(meth)acrylate/unsaturated carboxylic acid-based
copolymer (B), wherein: the average molecular weight (X) of the
polyalkylene glycol (A) is in the range of 400 to 10,000; the
average molecular weight (X) of the polyalkylene glycol (A) and the
average molecular weight (Y) of a polyalkylene glycol chain portion
of the copolymer (B) satisfy the following equation (1):
0.9<(X/Y)<1.1 (1);
[0014] and
[0015] the weight ratio of the polyalkylene glycol (A) to the
copolymer (B) is in the range of (A)/(B)=0.02 to 0.3.
[0016] In addition, a cement composition, according to the present
invention, at least comprises the above cement admixture according
to the present invention, water, and cement.
[0017] These and other objects and the advantages of the present
invention will be more fully apparent from the following detailed
disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The cement admixture, according to the present invention,
comprises a polyalkylene glycol (A) (which might hereinafter simply
be abbreviated to component A) and a polyalkylene glycol
mono(meth)acrylate/unsaturated carboxylic acid-based copolymer (B)
(which might hereinafter simply be abbreviated to component B).
Hereinafter, each of them is explained in detail.
Polyalkylene Glycol (A)
[0019] The component A in the present invention is, for example,
represented by the following general formula (2):
R.sub.1O(AO).sub.mH (2)
[0020] wherein:
[0021] AO represents an oxyalkylene group having 2 to 18 carbon
atoms (wherein: the AO-repeating units may be either identical with
or different from each other and, if the AO-repeating units are in
the form of a mixture of at least two thereof, they may be formed
by any of block addition, random addition, and alternating
addition);
[0022] m is an average molar number of addition of the oxyalkylene
groups and represents a number of 8 to 250; and
[0023] R.sup.1 represents a hydrogen atom or a hydrocarbon group
having 1 to 30 carbon atoms.
[0024] R.sup.1 in the formula (2) is especially favorably a
hydrocarbon group having 1 to 30 carbon atoms, more favorably 1 to
22 carbon atoms, still more favorably 1 to 18 carbon atoms,
particularly favorably 1 to 12 carbon atoms. In particular,
favorably for obtaining high drying shrinkage reducibility, R.sup.1
is a hydrocarbon group having 4 to 12 carbon atoms. Specific
examples of R.sup.1 include: alkyl groups having 1 to 30 carbon
atoms; benzene ring-containing aromatic groups having 6 to 30
carbon atoms, such as a phenyl group, alkylphenyl groups,
phenylalkyl groups, alkyl group-substituted or phenyl
group-substituted phenyl groups, and a naphthyl group; and alkenyl
groups having 2 to 30 carbon atoms.
[0025] AO in the formula (2) is particularly favorably a linear or
branched oxyalkylene group having 2 to 8 carbon atoms. Examples
thereof include an oxyethylene group, an oxypropylene group, an
oxybutylene group, and an oxystyrene group. Of these groups, the
oxyethylene group, the oxypropylene group, and the oxybutylene
group are favorable.
[0026] Specific examples of the component A include:
alkoxypolyalkylene glycols obtained by addition reactions of
alkylene oxides having 2 to 18 carbon atoms to any of the following
alcohols: saturated aliphatic alcohols having 1 to 30 carbon atoms,
such as methanol, ethanol, 2-propanol, 1-butanol, octanol,
2-ethyl-1-hexanol, nonyl alcohol, lauryl alcohol, cetyl alcohol,
and stearyl alcohol; unsaturated aliphatic alcohols having 3 to 30
carbon atoms, such as allyl alcohol, methallyl alcohol, crotyl
alcohol, and oleyl alcohol; alicyclic alcohols having 3 to 30
carbon atoms, such as cyclohexanol; and aromatic alcohols having 6
to 30 carbon atoms, such as phenol, phenylmethanol (benzyl
alcohol), methylphenol (cresol), p-ethylphenol, dimethylphenol
(xylenol), p-t-butylphenol, nonylphenol, dodecylphenol,
phenylphenol, and naphthol; and further include polyalkylene
glycols, such as polyethylene glycol, polypropylene glycol, and
polyethylene polypropylene glycol.
[0027] In the present invention, it is important that the average
molecular weight (X) of the aforementioned component A is in the
range of 400 to 10,000. In the case where the average molecular
weight (X) of the component A is less than 400 or more than 10,000,
it is difficult to display sufficient drying shrinkage reducibility
even using a small quantity. The average molecular weight (X) of
the component A is favorably in the range of 500 to 9,000, more
favorably 700 to 8,000, still more favorably 900 to 7,000, most
favorably 1,000 to 6,000. Incidentally, in the present invention,
the average molecular weight (X) of the component A can easily be
calculated from the terminal end group, the sorts of the
oxyalkylene groups, and their average molar number of addition in
the component A. For example, if R.sup.1, AO, and m in the general
formula (2) are a methyl group, ethylene oxide, and 25
respectively, the average molecular weight (X) of the component A
is calculated as 32+44.times.25=1,132. The average molar number of
addition of the oxyalkylene groups in the component A (m in the
formula (2)) is favorably in the range of 10 to 220, more favorably
15 to 200, still more favorably 20 to 170, most favorably 22 to
150, for the average molecular weight (X) of the component A to be
in the above favorable range.
Polyalkylene Glycol Mono(meth)acrylate/unsaturated Carboxylic
Acid-based Copolymer (B)
[0028] The component (B) in the present invention comprises the
following essential constitutional units: a unit (I) of the general
formula (3) below as derived from a polyalkylene glycol
mono(meth)acrylate-based monomer; and a unit (II) of the general
formula (4) below as derived from an unsaturated carboxylic
acid-based monomer. 1
[0029] wherein:
[0030] R.sup.2 and R.sup.3, independently of each other, represent
a hydrogen atom or a methyl group;
[0031] R.sup.4O represents an oxyalkylene group having 2 to 18
carbon atoms (wherein: the R.sup.4O-repeating units may be either
identical with or different from each other and, if the
R.sup.4O-repeating units are in the form of a mixture of at least
two thereof, they may be formed by any of block addition, random
addition, and alternating addition);
[0032] n is an average molar number of addition of the oxyalkylene
groups and represents a number of 8 to 250; and
[0033] R.sup.5 represents a hydrogen atom or a hydrocarbon group
having 1 to 30 carbon atoms. 2
[0034] wherein:
[0035] R.sup.6, R.sup.7 and R.sup.8, independently of each other,
denote a hydrogen atom, a methyl group or a (CH.sub.2).sub.pCOOX
group;
[0036] X denotes a hydrogen atom, a monovalent metal, a divalent
metal, an ammonium group or an organic amine group; and
[0037] p denotes an integer of 0 to 2;
[0038] wherein if at least two COOX groups exist they may be in the
form of an anhydride.
[0039] R.sup.5 in the formula (3) is especially favorably a
hydrocarbon group having 1 to 30 carbon atoms, more favorably 1 to
22 carbon atoms, still more favorably 1 to 18 carbon atoms,
particularly favorably 1 to 12 carbon atoms. Examples of the
hydrocarbon group having 1 to 30 carbon atoms include the same as
those previously cited as examples of R.sup.1 in the aforementioned
formula (2).
[0040] R.sup.4O in the formula (3) is particularly favorably a
linear or branched oxyalkylene group having 2 to 8, more favorably
2 to 4 carbon atoms. Examples thereof include an oxyethylene group,
an oxypropylene group, an oxybutylene group, and an oxystyrene
group. Of these groups, the oxyethylene group, the oxypropylene
group, and the oxybutylene group are favorable.
[0041] Examples of a monomer (a) to give the constitutional unit
(I) of the formula (3) include: adducts obtained by addition
reactions of alkylene oxides having 2 to 18 carbon atoms to
(meth)acrylic acid; and compounds obtained by esterification of
alkoxypolyalkylene glycols with (meth)acrylic acid, wherein the
alkoxypolyalkylene glycols are obtained by addition reactions of
alkylene oxides having 2 to 18 carbon atoms to any of the following
alcohols: saturated aliphatic alcohols having 1 to 30 carbon atoms,
such as methanol, ethanol, 2-propanol, 1-butanol, octanol,
2-ethyl-1-hexanol, nonyl alcohol, lauryl alcohol, cetyl alcohol,
and stearyl alcohol; unsaturated aliphatic alcohols having 3 to 30
carbon atoms, such as allyl alcohol, methallyl alcohol, crotyl
alcohol, and oleyl alcohol; alicyclic alcohols having 3 to 30
carbon atoms, such as cyclohexanol; and aromatic alcohols having 6
to 30 carbon atoms, such as phenol, phenylmethanol (benzyl
alcohol), methylphenol (cresol), p-ethylphenol, dimethylphenol
(xylenol), p-t-butylphenol, nonylphenol, dodecylphenol,
phenylphenol, and naphthol.
[0042] Specific examples of the monomer (a) include: various
polyalkylene glycol mono(meth)acrylates such as polyethylene glycol
mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and
polybutylene glycol mono(meth)acrylate; and various
alkoxypolyalkylene glycol mono(meth)acrylates, for example, as
follows: various alkoxypolyethylene glycol mono(meth)acrylates such
as methoxypolyethylene glycol mono(meth)acrylate,
ethoxypolyethylene glycol mono(meth)acrylate, 1-propoxypolyethylene
glycol mono(meth)acrylate, 2-propoxypolyethylene glycol
mono(meth)acrylate, 1-butoxypolyethylene glycol mono(meth)acrylate,
2-butoxypolyethylene glycol mono(meth)acrylate,
2-methyl-1-propoxypolyethylene glycol mono(meth)acrylate,
2-methyl-2-propoxypolyethylene glycol mono(meth)acrylate,
cyclohexoxypolyethylene glycol mono(meth)acrylate,
1-octoxypolyethylene glycol mono(meth)acrylate, 2- ethyl-1-h
exoxypolyethylene glycol mono (meth)acrylate,
nonylalkoxypolyethylene glycol mono(meth)acrylate,
laurylalkoxypolyethylene glycol mono(meth )acrylate,
cetylalkoxypolyethylene glycol mono(meth)acrylate,
stearylalkoxypolyethylene glycol mono(meth)acrylate,
phenoxypolyethylene glycol mono(meth)acrylate,
phenylmethoxypolyethylene glycol mono(meth)acrylate,
methylphenoxypolyethylene glycol mono(meth)acrylate,
p-ethylphenoxypolyethylene glycol mono(meth)acrylate,
dimethylphenoxypolyethylene glycol mono(meth)acrylate,
p-t-butylphenoxypolyethylene glycol mono(meth)acrylate,
nonylphenoxypolyethylene glycol mono(meth)acrylate,
dodecylphenoxypolyethylene glycol mono(meth)acrylate,
phenylphenoxypolyethylene glycol mono(meth)acrylate,
naphthoxypolyethylene glycol mono(meth)acrylate, products by
esterification of ethylene-oxide-added allyl alcohol with acrylic
acid, products by esterification of ethylene-oxide-added methallyl
alcohol with acrylic acid, and products by esterification of
ethylene-oxide-added crotyl alcohol with acrylic acid; various
alkoxypolypropylene glycol mono(meth)acrylates such as
methoxypolypropylene glycol mono(meth)acrylate, ethoxypolypropylene
glycol mono(meth)acrylate, 1-propoxypolypropylene glycol
mono(meth)acrylate, 2-propoxypolypropylene glycol
mono(meth)acrylate, 1-butoxypolypropylene glycol
mono(meth)acrylate, 2-butoxypolypropylene glycol
mono(meth)acrylate, products by esterification of
propylene-oxide-added allyl alcohol with acrylic acid, products by
esterification of propylene-oxide-added methallyl alcohol with
acrylic acid, and products by esterification of
propylene-oxide-added crotyl alcohol with acrylic acid; various
alkoxypolybutylene glycol mono(meth)acrylates such as
methoxypolybutylene glycol mono(meth)acrylate, ethoxypolybutylene
glycol mono(meth)acrylate, 1-propoxypolybutylene glycol
mono(meth)acrylate, 2-propoxypolybutylene glycol
mono(meth)acrylate, 1-butoxypolybutylene glycol mono(meth)acrylate,
2-butoxypolybutylene glycol mono(meth)acrylate, products by
esterification of butylene-oxide-added allyl alcohol with acrylic
acid, products by esterification of butylene-oxide-added methallyl
alcohol with acrylic acid, and products by esterification of
butylene-oxide-added crotyl alcohol with acrylic acid; and products
by esterification of at-least-two-alkylene-oxides-added alcohols
with (meth)acrylic acid, such as methoxypolyethylene glycol
polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol
polybutylene glycol mono(meth)acrylate, and methoxypolyethylene
glycol polystyrene glycol mono(meth)acrylate. These monomers (a)
may be used either alone respectively or in combinations with each
other.
[0043] Incidentally, the average molar number of addition of the
oxyalkylene groups in the monomer (a) and the constitutional unit
(I) (n in the formula (3)) is in the range of 8 to 250. As to this
average molar number of addition, there is the following tendency:
as the average molar number of addition decreases, the
hydrophilicity lowers, while as the average molar number of
addition increases, the reactivity lowers. Therefore, the average
molar number of addition is favorably in the range of 10 to 220,
more favorably 15 to 200, still more favorably 20 to 170,
particularly favorably 22 to 150.
[0044] The monomers (a) (constitutional units (I)) may be used
either alone respectively or in combinations with each other.
However, in the case where only one kind thereof is used, it is
favorable for ensuring a balance between hydrophilicity and
hydrophobicity that the oxyethylene group is indispensable as the
oxyalkylene group, and further that the ratio of the oxyethylene
group is not less than 50 mol % of the oxyalkylene groups. In
addition, in the case where at least two kinds of monomers (a)
(constitutional units (I)) are used, it is favorable that at least
any one kind of them includes the oxyethylene group as the
oxyalkylene group.
[0045] The constitutional unit (I) content is not especially
limited, but is fitly not less than 5 weight %, favorably not less
than 10 weight %, more favorably not less than 20 weight %, still
more favorably not less than 30 weight %, particularly favorably
not less than 40 weight %, most favorably not less than 50 weight
%, of the entirety of the copolymer as the component B.
[0046] Specific examples of a monomer (b) to give the
constitutional unit (II) of the formula (4) include: unsaturated
monocarboxylic acid-based monomers, such as acrylic acid,
methacrylic acid, crotonic acid, and their metal salts, ammonium
salts, and amine salts; unsaturated dicarboxylic acid-based
monomers, such as maleic acid, itaconic acid, citraconic acid,
fumaric acid, and their metal salts, ammonium salts, and amine
salts; and further, anhydrides of unsaturated dicarboxylic
acid-based monomers, such as maleic anhydride, itaconic anhydride,
and citraconic anhydride. Of these monomers, the unsaturated
monocarboxylic acid-based monomers are favorable, and (meth)acrylic
acid and their salts are particularly favorable. These monomers (b)
may be used either alone respectively or in combinations with each
other.
[0047] The constitutional unit (II) content is not especially
limited. In the present invention, however, the milliequivalent
number of carboxyl groups in the component B is particularly
favorably in the range of 0.25 to 5.00 meq per 1 g of the copolymer
as the component B assuming all the carboxyl groups in the
component B to be in unneutralized forms. This milliequivalent
number of carboxyl groups is more favorably in the range of 0.25 to
4.50 meq/g, still more favorably 0.25 to 4.00 meq/g, particularly
favorably 0.25 to 3.50 meq/g, most favorably 0.30 to 3.00 meq/g. In
the case where this milliequivalent number of carboxyl groups is
smaller than 0.25 meq/g, the dispersibility of the copolymer which
is the component B is so much low that it is difficult to obtain
sufficient fluidity when a cement composition is prepared. On the
other hand, in the case where the milliequivalent number of
carboxyl groups is larger than 5.00 meq/g, the fluidity is apt to
decrease with the passage of time when a cement composition is
prepared.
[0048] Incidentally, assuming all the carboxyl groups in the
component B to be in unneutralized forms, the milliequivalent
number of carboxyl groups in the component B can be calculated as
follows. For example, in the case where the copolymerization is
carried out in the composition ratio of monomer (a)/monomer
(b)=90/10 (weight %) using acrylic acid as the monomer (b), the
milliequivalent number of carboxyl groups per 1 g of the copolymer
is calculated as (0.1/72).times.1000=1.39 (meq/g) (calculation
example 1), because the molecular weight of acrylic acid is 72. In
addition, for example, in the case where the copolymerization is
carried out in the composition ratio of monomer (a)/monomer
(b)=90/10 (weight %) using sodium methacrylate as the monomer (b),
the milliequivalent number of carboxyl groups per 1 g of the
copolymer is calculated as
(0.1.times.86/108)/{(0.9+0.1.times.86/108).times.86}1000=0.- 95
(meq/g) (calculation example 2), because the molecular weight of
sodium methacrylate is 108 and because the molecular weight of
methacrylic acid is 86. Incidentally, also in the case where
methacrylic acid is used during the polymerization and where
carboxyl groups derived from methacrylic acid are neutralized with
sodium hydroxide after the polymerization, the calculation can be
carried out in the same way as of the above calculation example 2.
In addition, for example, in the case where the copolymerization is
carried out in the composition ratio of monomer (a)/monomer
(b)=90/10 (weight %) using sodium maleate as the monomer (b), the
milliequivalent number of carboxyl groups per 1 g of the copolymer
is calculated as (0.1.times.116/160)/{(0.9+0.1.times.116/160).t-
imes.116/2}.times.1000=1.29 (meq/g) (calculation example 3),
because the molecular weight of sodium maleate is 160 and because
the molecular weight of maleic acid is 116 and because maleic acid
has two carboxyl groups per molecule.
[0049] There is no especial limitation with regard to the ratio
between the aforementioned constitutional units (I) and (II) if
this ratio satisfies the aforementioned range of the
milliequivalent number of carboxyl groups assuming all the carboxyl
groups in the component B to be in unneutralized forms. However,
this ratio is usually favorably in the range of constitutional unit
(I)/constitutional unit (II)=(50 to 99)/(1 to 50) (weight %), more
favorably (55 to 99)/(1 to 45) (weight %), still more favorably (60
to 98)/(2 to 40) (weight %), particularly favorably (65 to 98)/(2
to 35) (weight %), most favorably (70 to 97)/(3 to 30) (weight
%).
[0050] The copolymer which is the component B may further comprise
another constitutional unit (III) in addition to the constitutional
unit (I) of the general formula (3) and the constitutional unit
(II) of the general formula (4), if necessary.
[0051] There is no especial limitation with regard to a monomer (c)
to give the constitutional unit (III) if this monomer (c) is
copolymerizable with the aforementioned monomers (a) and (b).
Examples thereof include: half esters and diesters of unsaturated
dicarboxylic acids, such as maleic acid, fumaric acid, itaconic
acid, and citraconic acid, with alcohols having 1 to 30 carbon
atoms; half amides and diamides of the aforementioned unsaturated
dicarboxylic acids with amines having 1 to 30 carbon atoms; half
esters and diesters of the aforementioned unsaturated dicarboxylic
acids with alkyl (poly)alkylene glycols as obtained by addition
reactions of 1 to 500 mols of alkylene oxides having 2 to 18 carbon
atoms to the aforementioned alcohols or amines; half esters and
diesters of the aforementioned unsaturated dicarboxylic acids with
glycols having 2 to 18 carbon atoms or with polyalkylene glycols of
2 to 500 in molar number of addition of the foregoing glycols; half
amides of maleamic acid with glycols having 2 to 18 carbon atoms or
with polyalkylene glycols of 2 to 500 in molar number of addition
of the foregoing glycols; (poly)alkylene glycol di(meth)acrylates
such as triethylene glycol di(meth)acrylate, (poly)ethylene glycol
di(meth)acrylate, polypropylene glycol di(meth)acrylate, and
(poly)ethylene glycol (poly)propylene glycol di(meth)acrylate;
multifunctional (meth)acrylates such as hexanediol
di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and
trimethylolpropane di(meth)acrylate; (poly)alkylene glycol
dimaleates such as triethylene glycol dimaleate and polyethylene
glycol dimaleate; unsaturated sulfonic acids, such as
vinylsulfonate, (meth)allylsulfonate,
2-(meth)acryloxyethylsulfonate, 3-(meth)acryloxypropylsulfonate,
3-(meth)acryloxy-2-hydroxypropylsulfonate,
3-(meth)acryloxy-2-hydroxyprop- ylsulfophenyl ether,
3-(meth)acryloxy-2-hydroxypropyloxysulfobenzoate, 4-(
meth)acryloxybutylsulfonate, (meth)acrylamidomethylsulfonic acid,
(meth)acrylamidoethylsulfonic acid, 2-methylpropanesulfonic acid
(meth)acrylamide, and styrenesulfonic acid, and their monovalent
metal salts, divalent metal salts, ammonium salts, and organic
amine salts; esters of unsaturated monocarboxylic acids with
alcohols having 1 to 30 carbon atoms, such as methyl
(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate,
glycidyl (meth)acrylate, methyl crotonate, ethyl crotonate, and
propyl crotonate; amides of unsaturated monocarboxylic acids with
amines having 1 to 30 carbon atoms, such as methyl(meth)acrylamide;
vinyl aromatic compounds such as styrene, .alpha.-methylstyrene,
vinyltoluene, and p-methylstyrene; alkanediol mono(meth)acrylates
such as 1,4-butanediol mono(meth)acrylate, 1,5-pentanediol
mono(meth)acrylate, and 1,6-hexanediol mono(meth)acrylate; dienes
such as butadiene, isoprene, 2-methyl-1,3-butadiene, and
2-chloro-1,3-butadiene; unsaturated amides such as
(meth)acrylamide, (meth)acrylalkylamide, N-methylol(meth)acrylami-
de, and N,N-dimethyl(meth)acrylamide; unsaturated cyanes such as
(meth)acrylonitrile and .alpha.-chloroacrylonitrile; unsaturated
esters such as vinyl acetate and vinyl propionate; unsaturated
amines such as aminoethyl (meth)acrylate, methylaminoethyl
(meth)acrylate, dimethylaminoethyl (meth)acrylate,
dimethylaminopropyl (meth)acrylate, dibutylaminoethyl
(meth)acrylate, and vinylpyridine; divinyl aromatic compounds such
as divinylbenzene; cyanurates such as triallyl cyanurate; allyl
compounds such as (meth)allyl alcohol and glycidyl (meth)allyl
ether; vinyl ethers or allyl ethers, such as methoxypolyethylene
glycol monovinyl ether, polyethylene glycol monovinyl ether,
methoxypolyethylene glycol mono(meth)allyl ether, and polyethylene
glycol mono(meth)allyl ether; and siloxane derivatives such as
polydimethylsiloxanepropylaminoma- leamic acid,
polydimethylsiloxaneaminopropyleneaminomaleamic acid,
polydimethylsiloxanebis(propylaminomaleamic acid),
polydimethylsiloxanebis(dipropyleneaminomaleamic acid),
polydimethylsiloxane-(1-propyl-3-acrylate),
polydimethylsiloxane-(1-propy- l-3-methacrylate),
polydimethylsiloxanebis(l-propyl-3-acrylate), and
polydimethylsiloxanebis(1-propyl-3-methacrylate). These may be used
either alone respectively or in combinations with each other.
[0052] There is no especial limitation with regard to the
constitutional unit (III) content if it is within the range which
does not damage the effects of the present invention, but this
content is favorably not more than 70 weight %, more favorably not
more than 60 weight %, still more favorably not more than 50 weight
%, particularly favorably not more than 40 weight %, most favorably
not more than 30 weight %, of the entirety of the copolymer as the
component B.
[0053] The ratio between the constitutional units composing the
copolymer which is the component B is fitly in the range of
constitutional unit (I)/constitutional unit (II)/constitutional
unit (III)=(5 to 99)/(1 to 50)/(0 to 70) (weight %), favorably (10
to 99)/(1 to 45)/(0 to 60) (weight %), more favorably (20 to 98)/(2
to 40)/(0 to 50) (weight %), still more favorably (30 to 98)/(2 to
35)/(0 to 50) (weight %), particularly favorably (40 to 98)/(2 to
35)/(0 to 40) (weight %), and most favorably (50 to 97)/(3 to
30)/(0 to 30) (weight %) wherein the total of the constitutional
units (I), (II) and (III) is always 100 weight %.
[0054] The process for obtaining the copolymer which is the
component B is not especially limited. For example, the process may
comprise the step of, in the presence of a polymerization
initiator, copolymerizing monomer components including a monomer to
give the constitutional unit (I) (for example, the aforementioned
monomer (a)) and a monomer to give the constitutional unit (II)
(for example, the aforementioned monomer (b)) as essential
components and, if necessary, further including a monomer to give
the constitutional unit (III) (for example, the aforementioned
monomer (c)). The polymerization can be carried out by conventional
methods such as solution polymerization and bulk polymerization.
For specific example, the polymerization reaction may be carried
out within the range of usually 0 to 120.degree. C. using
polymerization initiators, such as ammonium persulfate, alkaline
metal persulfates, hydrogen peroxide, and azo compounds, in water
or lower alcohols such as methyl alcohol, ethyl alcohol, and
isopropyl alcohol.
[0055] In addition, thiol-based chain transfer agents such as
mercaptoethanol and 3-mercaptopropionic acid can further be used in
order to adjust the molecular weight of the resulting
copolymer.
[0056] The copolymer as obtained in the above way may be used as
the component B as it is. However, this copolymer may be used in a
polymer salt form by further being neutralized with an alkaline
substance, if necessary. Favorable examples of such an alkaline
substance include: inorganic substances such as hydroxides and
carbonates of mono- and divalent metals (typically, sodium
hydroxide); ammonia; and organic amines. Furthermore, it is also
possible that the copolymer is used in a solid form by evaporating
solvents as used to produce the copolymer.
[0057] In the present invention, it is important that the average
molecular weight (Y) of the polyalkylene glycol chain portion of
the component B satisfies the relation of the below-mentioned
equation (1) with the average molecular weight (X) of the
aforementioned component A.
0.9<(X/Y)<1.1 (1)
[0058] Only in the case where (X/Y) is in this range, in other
words, where the average molecular weight (X) of the component A is
nearly equal to the average molecular weight (Y) of the
polyalkylene glycol chain portion of the component B, there is a
specific interaction between the polyalkylene glycol (which is the
component A) and the polyalkylene glycol chain portion of the
component B, so that the drying shrinkage reduction effect can be
displayed sufficiently even using a small quantity. Incidentally,
in the present invention, the average molecular weight (Y) of the
polyalkylene glycol chain portion of the component B is the average
molecular weight of the portion corresponding to
O(R.sup.4O).sub.n--R.sup.5 in the aforementioned general formula
(3) and can easily be calculated in the following way. For example,
if R.sup.5, R.sup.4O, and n in the general formula (3) are a methyl
group, ethylene oxide, and 25 respectively, the average molecular
weight (Y) of the polyalkylene glycol chain portion of the
component B is calculated as 31+44.times.25=1,131.
[0059] There is no especial limitation with regard to the
weight-average molecular weight of the copolymer which is the
component B if, as is mentioned above, the average molecular weight
(Y) of the polyalkylene glycol chain portion of the component B
satisfies the aforementioned equation (1). However, the
weight-average molecular weight of the component B is favorably in
the range of 1,000 to 500,000, more favorably 5,000 to 300,000. In
the case where the weight-average molecular weight of the component
B is less than 1,000 or more than 500,000, there are disadvantages
in that the dispersibility is low.
[0060] It is important that the cement admixture according to the
present invention comprises the aforementioned components A and B
so that the weight ratio therebetween may be in the range of
(A)/(B)=0.02 to 0.3. In the case where the weight ratio between the
components A and B is less than (A)/(B)=0.02, the drying shrinkage
reduction effect is low. On the other hand, in the case where the
weight ratio is more than 0.3, the fluidity is low. Both the drying
shrinkage reducibility and the fluidity cannot be satisfied unless
the weight ratio between the components A and B ((A)/(B)) is in the
aforementioned range.
[0061] The production process for the cement admixture according to
the present invention is not especially limited. For example, the
process can comprise the steps of: copolymerizing the monomers (a)
and (b) in the aforementioned way to synthesize the component B;
and then mixing the components A and B together so that the weight
ratio therebetween may be in the aforementioned range. In this
process, it is possible to also easily produce a cement admixture
in which the component A does not have the same structure as that
of the polyalkylene glycol chain portion of the component B.
[0062] Another production process for the cement admixture
according to the present invention can also be used wherein this
production process, for example, comprises the steps of: carrying
out an esterification reaction of a polyalkylene glycol with
(meth)acrylic acid; and then stopping this esterification reaction
under conditions where a portion of the polyalkylene glycol
(=component A) remains unreacted; and then carrying out a
polymerization reaction in which the portion of the polyalkylene
glycol (=component A) is left to remain unreacted, thereby
synthesizing the component B (polyalkylene glycol
mono(meth)acrylate/unsa- turated carboxylic acid-based copolymer);
so that the weight ratio between the components A and B may be in
the aforementioned weight ratio range. In addition, the weight
ratio of between the components A and B may be adjusted into the
aforementioned range by further adding the component A later.
[0063] Yet another production process for the cement admixture
according to the present invention may also be used wherein this
production process, for example, comprises the steps of:
synthesizing the component B by what is called "post-esterification
reaction of polymer" which is a esterification reaction of an
alkoxypolyalkylene glycol having a C1 to C30 hydrocarbon group at
one terminal end directly with at least a part of carboxyl groups
of a polymer which is obtained by polymerizing a monomer component
including the unsaturated carboxylic acid-based monomer (b) as an
essential component; and then stopping this esterification reaction
so that the weight ratio between the polyalkylene glycol
(=component A) and the component B may be in the aforementioned
weight ratio range. In this process, the weight ratio of between
the components A and B may be adjusted into the aforementioned
range by further adding the component A later. Incidentally, in the
case where the component B is obtained by the so-called
"post-esterification reaction of polymer" in the above way, the
milliequivalent number of carboxyl groups in the copolymer (B)
assuming all the carboxyl groups in the copolymer (B) to be in
unneutralized forms cannot be calculated in the way of the
aforementioned calculation examples based on the monomers.
Therefore, the milliequivalent number may be calculated by
measuring the acid value of the polymer in consideration of counter
ion species of carboxyl groups in the polymer.
Cement Composition
[0064] The cement composition, according to the present invention,
at least comprises the cement admixture according to the present
invention, cement, and water as essential components, and is, for
example, usable as cement paste or as mortar, concrete,
self-levelling materials, and plaster by mixing the cement paste
further with aggregates such as sand and ballast. Particularly, the
cement composition can be used favorably also for mortar and
concrete which are required to have high fluidity, such as high
fluid concrete and self-filling concrete.
[0065] The aforementioned cement is a substance having a property
of hardening by its hydration reaction, and specific examples
thereof include: hydraulic cements, such as portland cements of
various types (e.g. normal types, high-early-strength types, and
ultra-high-early-strength types), various mixed cements (obtained
by mixing the aforementioned portland cements with such as blast
furnace slag, fly ash, cinder ash, clinker ash, husk ash, and
silica), white cements, ultra fast hardenable cements, and alumina
cements; and hydraulic materials such as gypsum.
[0066] The cement composition according to the present invention is
not especially limited with regard to the amount of cement as used
per 1 m.sup.3 of the cement composition and the amount of water as
used per 1 m.sup.3 of the cement composition (unit water amount).
However, for example, it is recommended that: the unit water amount
is in the range of 100 to 185 kg/m.sup.3, favorably 120 to 175
kg/m.sup.3; the amount of cement as used is in the range of 250 to
800 kg/m.sup.3, favorably 270 to 800 kg/m.sup.3; and the
water/cement weight ratio is in the range of 0.10 to 0.7, favorably
0.2 to 0.65. Thus, the cement composition according to the present
invention is usable in the wide range from a poor to rich content,
and is effective in all over the range from a high strength
concrete with a large unit cement amount to a poor content concrete
with a unit cement amount of not larger than 300 kg/m.sup.3.
[0067] The ratio of the cement admixture (component A+component B)
according to the present invention in the cement composition
according to the present invention is not especially limited, but
is recommended to be in the range of 0.001 to 15 weight %,
favorably 0.01 to 10 weight %, more favorably 0.02 to 5 weight %,
still more favorably 0.05 to 3 weight %, particular favorably 0.1
to 2 weight %, of the weight of cement. Particularly, when the
cement composition is used for such as mortar and concrete
containing the hydraulic cement, the ratio of the cement admixture
(component A+component B) according to the present invention is
recommended to be in the range of 0.01 to 10 weight %, favorably
0.02 to 5 weight %, more favorably 0.05 to 3 weight %, particular
favorably 0.1 to 2 weight %, of the weight of the hydraulic cement.
In the case where the total ratio of the components A and B is
smaller than 0.01 weight %, it is difficult to sufficiently obtain
the drying shrinkage reducibility and the fluidity. On the other
hand, even if the cement admixture is used in a ratio of larger
than 10 weight %, the resultant effects substantially reach the top
and do not increase any more, so there are economical
disadvantages.
[0068] The cement admixture according to the present invention may
further comprise conventional cement dispersants. The conventional
cement dispersant which is usable is not especially limited, but
examples thereof include: various sulfonic dispersants having a
sulfonic acid group in their molecules; and various polycarboxylic
dispersants having a polyoxyalkylene chain and a carboxyl group in
their molecules.
[0069] Examples of the aforementioned sulfonic dispersants include
ligninsulfonic acid salts, naphthalenesulfonic acid-formaldehyde
condensation products, melaminesulfonic acid-formaldehyde
condensation products, polystyrenesulfonic acid salts, and
aminosulfonic dispersants such as aminoarylsulfonic
acid-phenol-formaldehyde condensation products.
[0070] Examples of the aforementioned polycarboxylic dispersants
include: copolymers obtained by copolymerizing a monomer mixture
comprising three essential monomers, namely, a polyalkylene glycol
mono(meth)acrylate monomer (having a polyoxyalkylene chain of 2 to
300 in average molar number of addition of alkylene oxides having 2
to 3 carbon atoms), a (meth)acrylic monomer, and an alkyl
(meth)acrylate; copolymers obtained by copolymerizing a monomer
mixture comprising three essential monomers, namely, a polyalkylene
glycol mono(meth)acrylate monomer (having a polyoxyalkylene chain
of 2 to 300 in average molar number of addition of alkylene oxides
having 2 to 3 carbon atoms), a (meth)acrylic monomer, and any one
of (meth)allylsulfonic acid (or its salt), vinylsulfonic acid (or
its salt), and p-(meth)allyloxybenzenesulfonic acid (or its salt);
copolymers obtained by graft-polymerizing (meth)acrylamide and/or
2-(meth)acrylamido-2-methylpropanesulfonic acid onto copolymers
obtained by copolymerizing a monomer mixture comprising three
essential monomers, namely, a polyalkylene glycol
mono(meth)acrylate monomer (having a polyoxyalkylene chain of 2 to
50 in average molar number of addition of ethylene oxide), a
(meth)acrylic monomer, and (meth)allylsulfonic acid (or its salt);
copolymers obtained by copolymerizing a monomer mixture comprising
four essential monomers, namely, a polyethylene glycol
mono(meth)acrylate monomer (having a polyoxyalkylene chain of 5 to
50 in average molar number of addition of ethylene oxide), a
polyethylene glycol mono(meth)allyl ether monomer (having a
polyoxyalkylene chain of 1 to 30 in average molar number of
addition of ethylene oxide), a (meth)acrylic monomer, and any one
of (meth)allylsulfonic acid (or its salt) and
p-(meth)allyloxybenzenesulfonic acid (or its salt); copolymers
obtained by copolymerizing a monomer mixture comprising a
polyalkylene glycol mono(meth)allyl ether monomer (having a
polyoxyalkylene chain of 2 to 300 in average molar number of
addition of alkylene oxides having 2 to 18 carbon atoms) and a
maleic monomer as essential components; copolymers obtained by
copolymerizing a monomer mixture comprising a polyalkylene glycol
mono(meth)allyl ether monomer (having a polyoxyalkylene chain of 2
to 300 in average molar number of addition of alkylene oxides
having 2 to 4 carbon atoms) and a polyalkylene glycol maleate
monomer as essential components; and copolymers obtained by
copolymerizing a monomer mixture comprising a polyalkylene glycol
3-methyl-3-butenyl ether monomer (having a polyoxyalkylene chain of
2 to 300 in average molar number of addition of alkylene oxides
having 2 to 4 carbon atoms) and a maleic monomer as essential
components. Incidentally, these conventional cement dispersants can
also be used in combinations with each other.
[0071] In the case where the aforementioned conventional cement
dispersant is used, the mixing ratio by weight of the present
invention cement admixture (component A+component B) to the
conventional cement dispersant is favorably in the range of 5:95 to
95:5, more favorably 10:90 to 90:10, though not uniformly
determinable, depending on differences in factors such as kind,
composition, and test conditions of the conventional cement
dispersant as used.
[0072] The cement admixture according to the present invention may
further comprise, besides the aforementioned conventional cement
dispersant, other conventional cement additives (materials to add
to cement) such as (1) to (20) as exemplified below:
[0073] (1) water-soluble high-molecular substances, for example:
unsaturated carboxylic acid polymers such as poly(acrylic acid) (or
its sodium salt), poly(methacrylic acid) (or its sodium salt),
poly(maleic add) (or its sodium salt), and sodium salts of acrylic
acid-maleic acid copolymers; nonionic cellulose ethers such as
methyl cellulose, ethyl cellulose, hydroxymethyl cellulose,
hydroxyethyl cellulose, carboxymethyl cellulose, carboxyethyl
cellulose, and hydroxypropyl cellulose; polysaccharides produced by
microbiological fermentation such as yeast glucan, xanthane gum,
and .beta.-1.3 glucans (which may be either a linear or branched
chain type and of which examples include curdlan, paramylon,
vacciman, scleroglucan and laminaran); polyacrylamide; poly(vinyl
alcohol); starch; starch phosphate; sodium alginate; gelatin; and
acrylic acid copolymers having an amino group in their molecules
and their quaternized compounds;
[0074] (2) high-molecular emulsions, for example: copolymers of
various vinyl monomers such as alkyl (meth)acrylates;
[0075] (3) retarders, for example: oxycarboxylic acids, such as
gluconic acid, glucoheptonic acid, arabonic acid, malic acid and
citric acid, and their inorganic or organic salts with such as
sodium, potassium, calcium, magnesium, ammonium and
triethanolamine; saccharides, for example, monosaccharides such as
glucose, fructose, galactose, saccharose, xylose, apiose, ribose,
and isomerized saccharides, or oligosaccharides such as
disaccharides and trisaccharides, or oligosaccharides such as
dextrin, or polysaccharides such as dextran, or molasses including
them; sugar alcohols such as sorbitol; magnesium silicofluoride;
phosphoric acid and its salts or borates; aminocarboxylic acids and
their salts; alkali-soluble proteins; fumic acid; tannic acid;
phenol; polyhydric alcohols such as glycerol; and phosphonic acids
and derivatives therefrom, such as aminotri(methylenephosphonic
acid), 1-hydroxyethylidene-1,1-diphosphonic acid,
ethylenediaminetetra(methylene- phosphonic acid),
diethylenetriaminepenta(methylenephosphonic acid), and their
alkaline metal salts and alkaline earth metal salts;
[0076] (4) high-early-strength agents and promoters, for example:
soluble calcium salts such as calcium chloride, calcium nitrite,
calcium nitrate, calcium bromide, and calcium iodide; chlorides
such as iron chloride and magnesium chloride; sulfates; potassium
hydroxide; sodium hydroxide; carbonates; thiosulfates; formic acid
and formates such as calcium formate; alkanol amines; alumina
cements; and calcium aluminate silicate;
[0077] (5) mineral oil base defoaming agents, for example: kerosine
and liquid paraffin;
[0078] (6) oils-and-fats base defoaming agents, for example: animal
and plant oils, sesame oil, castor oil and their alkylene oxide
adducts;
[0079] (7) fatty acid base defoaming agents, for example: oleic
acid, stearic acid and their alkylene oxide adducts;
[0080] (8) fatty acid ester base defoaming agents, for example:
glycerol monoricinolate, alkenyl succinic acid derivatives,
sorbitol monolaurate, sorbitol trioleate, and natural wax;
[0081] (9) oxyalkylene base defoaming agents, for example:
polyoxyalkylenes such as (poly)oxyethylene (poly)oxypropylene
adducts; (poly)oxyalkyl ethers such as diethylene glycol heptyl
ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether,
polyoxyethylene polyoxypropylene 2-ethylhexyl ether, and adducts
obtained by addition reactions of oxyethylene oxypropylene to
higher alcohols having 12 to 14 carbon atoms; (poly)oxyalkylene
(alkyl) aryl ethers such as polyoxypropylene phenyl ether and
polyoxyethylene nonyl phenyl ether; acetylene ethers as formed by
addition polymerization of alkylene oxides to acetylene alcohols
such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol,
2,5-dimethyl-3-hexyne-2,5-diol, and 3-methyl-1-butyn-3-ol;
(poly)oxyalkylene fatty acid esters such as diethylene glycol
oleate, diethylene glycol laurate, and ethylene glycol distearate;
(poly)oxyalkylene sorbitan fatty acid esters such as
(poly)oxyethylene sorbitan monolaurate and (poly)oxyethylene
sorbitan trioleate; (poly)oxyalkylene alkyl (aryl) ether sulfuric
acid ester salts such as sodium polyoxypropylene methyl ether
sulfate and sodium polyoxyethylene dodecylphenol ether sulfate;
(poly)oxyalkylene alkyl phosphoric acid esters such as
(poly)oxyethylene stearyl phosphate; (poly)oxyalkylene alkylamines
such as polyoxyethylene laurylamine; and polyoxyalkylene amide;
[0082] (10) alcohol base defoaming agents, for example: octyl
alcohol, hexadecyl alcohol, acetylene alcohol, and glycols;
[0083] (11) amide base defoaming agents, for example: acrylate
polyamines;
[0084] (12) phosphoric acid ester base defoaming agents, for
example: tributyl phosphate and sodium octyl phosphate;
[0085] (13) metal soap base defoaming agents, for example: aluminum
stearate and calcium oleate;
[0086] (14) silicone base defoaming agents, for example: dimethyl
silicone oils, silicone pastes, silicone emulsions,
organic-denatured polysiloxanes (polyorganosiloxanes such as
dimethyl polysiloxane), and fluorosilicone oils;
[0087] (15) AE agents, for example: resin soap, saturated or
unsaturated fatty acids, sodium hydroxystearate, lauryl sulfate,
ABS (alkylbenzenesulfonic acids), LAS (linear alkylbenzenesulfonic
acids), alkanesulfonates, polyoxyethylene alkyl (phenyl) ethers,
polyoxyethylene alkyl (phenyl) ether sulfuric acid esters or their
salts, polyoxyethylene alkyl (phenyl) ether phosphoric acid esters
or their salts, protein materials, alkenylsulfosuccinic acids, and
.alpha.-olefinsulfonates;
[0088] (16) other surfactants, for example: alkyl diphenyl ether
sulfonates as formed by ether-bonding of two phenyl groups having a
sulfonic acid group, which may have an alkyl or alkoxy group as a
substituent; various kinds of anionic surfactants; various kinds of
cationic surfactants such as alkylamine acetate and
alkyltrimethylammonium chloride; various kinds of nonionic
surfactants; and various kinds of amphoteric surfactants;
[0089] (17) waterproofing agents, for example: fatty acids (or
their salts), fatty acid esters, oils and fats, silicone, paraffin,
asphalt, and wax;
[0090] (18) anticorrosives, for example: nitrous acid salts,
phosphoric acid salts, and zinc oxide;
[0091] (19) fissure-reducing agents, for example: polyoxyalkyl
ethers; and
[0092] (20) swelling materials, for example: ettringite base and
lime base ones.
[0093] The cement composition according to the present invention
may further comprise conventional cement additives (materials to
add to cement) other than the above. Examples thereof include:
cement humectants, thickeners, flocculants, strength-enhancing
agents, self-levelling agents, colorants, moldproofing agents,
pozzolan, and zeolite. Incidentally, these cement additives
(materials to add to cement) can be contained either alone
respectively or in combinations with each other.
[0094] Examples of particularly favorable embodiments with regard
to components other than cement and water in the cement composition
according to the present invention include the following 1) to
6):
[0095] 1) A combination comprising the following two essential
components: (1) the present invention cement admixture and (2) the
oxyalkylene base defoaming agent. Incidentally, the mixing ratio by
weight of (2) the oxyalkylene base defoaming agent is favorably in
the range of 0.01 to 10 weight % of the component B in (1) the
present invention cement admixture. 2) A combination comprising the
following two essential components: (1) the present invention
cement admixture and (2) the sulfonic dispersant having a sulfonic
acid group in its molecule. Incidentally, the mixing ratio by
weight of (1) the present invention cement admixture to (2) the
sulfonic dispersant is favorably in the range of 5:95 to 95:5, more
favorably 10:90 to 90:10.
[0096] 3) A combination comprising the following two essential
components: (1) the present invention cement admixture and (2) the
ligninsulfonic acid salt. Incidentally, the mixing ratio by weight
of (1) the present invention cement admixture to (2) the
ligninsulfonic acid salt is favorably in the range of 5:95 to 95:5,
more favorably 10:90 to 90:10.
[0097] 4) A combination comprising the following two essential
components: (1) the present invention cement admixture and (2) a
material-separation-decreasing agent. Usable examples of the
material-separation-decreasing agent include: various thickeners
such as nonionic cellulose ethers; and compounds having a
hydrophobic substituent, namely, a C4 to C30 hydrocarbon chain, as
a partial structure, and further having a polyoxyalkylene chain of
2 to 300 in average molar number of addition of C2 to C18 alkylene
oxides as another partial structure. Incidentally, the mixing ratio
by weight of (1) the present invention cement admixture to (2) the
material-separation-decreas- ing agent is favorably in the range of
10:90 to 99.99:0.01, more favorably 50:50 to 99.9:0.1. The cement
composition comprising this combination is favorable as high fluid
concrete, self-filling concrete, and self-levelling materials.
[0098] 5) A combination comprising the following two essential
components: (1) the present invention cement admixture and (2) the
retarder. Incidentally, the mixing ratio by weight of (1) the
present invention cement admixture to (2) the retarder is favorably
in the range of 50:50 to 99.9:0.1, more favorably 70:30 to
99:1.
[0099] 6) A combination comprising the following two essential
components: (1) the present invention cement admixture and (2) the
promotor. Incidentally, the mixing ratio by weight of (1) the
present invention cement admixture to (2) the promotor is favorably
in the range of 10:90 to 99.9:0.1, more favorably 20:80 to
99:1.
Effects and Advantages of the Invention
[0100] The present invention enables to display excellent cracking
inhibition effect and further to bring about good fluidity even if
the quantity of the addition is small.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0101] Hereinafter, the present invention is more specifically
illustrated by the following examples of some preferred embodiments
in comparison with comparative examples not according to the
invention. However, the invention is not limited to the
below-mentioned examples. Incidentally, in the examples, unless
otherwise noted, the units "part(s)" and "%" denote those by
weight. In addition, the weight-average molecular weight of
copolymer (B) is in terms of polyethylene glycol by gel permeation
chromatography (GPC).
[0102] Used as the raw polyalkylene glycols (A) are the following
four:
Polyalkylene glycols (A)
[0103] (A-1): 1-Butoxypolyethylene glycol (average molar number of
addition of ethylene oxide: 25, average molecular weight (X) as
calculated from the terminal end group, the sort of the oxyalkylene
group, and its average molar number of addition: 1,174)
[0104] (A-2): 1-Butoxypolyethylene glycol (average molar number of
addition of ethylene oxide: 75, average molecular weight (X) as
calculated from the terminal end group, the sort of the oxyalkylene
group, and its average molar number of addition: 3,374)
[0105] (A-3): Methoxypolyethylene glycol (average molar number of
addition of ethylene oxide: 25, average molecular weight (X) as
calculated from the terminal end group, the sort of the oxyalkylene
group, and its average molar number of addition: 1,132)
[0106] (A-4): Polyethylene glycol (average molar number of addition
of ethylene oxide: 5, average molecular weight (X) as calculated
from the terminal end group, the sort of the oxyalkylene group, and
its average molar number of addition: 238)
[0107] The raw polyalkylene glycol mono(meth)acrylate/(meth)acrylic
acid- based copolymers (B) were obtained in the following ways:
Production Example 1 (Production of Copolymer (B-1))
[0108] First of all, 1,698 parts of ion-exchanged water was placed
into a glass-made reactor as equipped with a thermometer, a
stirrer, a dropping funnel, a nitrogen-introducing tube and a
reflux condenser. The internal air of the reactor was then replaced
with nitrogen under stirring, and the reactor was then heated to
80.degree. C. under the nitrogen atmosphere. Next, an aqueous
monomer solution, as prepared by mixing 1,668 parts of
1-butoxypolyethylene glycol monomethacrylate (average molar number
of addition of ethylene oxide: 25), 332 parts of methacrylic acid,
500 parts of ion-exchanged water, and 16.7 parts of
3-mercaptopropionic acid (chain transfer agent), was dropwise added
into the reactor over a period of 4 hours, and simultaneously with
the initiation of this dropwise addition of the aqueous monomer
solution, an aqueous initiator solution comprising 23 parts of
ammonium persulfate and 207 parts of ion-exchanged water was
dropwise added into the reactor over a period of 5 hours.
Subsequently to the end of the dropwise addition of the aqueous
initiator solution, the internal temperature of the reactor was
maintained at 80.degree. C. for 1 hour to complete the
polymerization reaction. Thereafter, the resultant reaction mixture
was neutralized with a 30% aqueous sodium hydroxide solution, thus
obtaining an aqueous solution of a copolymer (B-1) having a
weight-average molecular weight of 27,000. Incidentally, the
milliequivalent number of carboxyl groups in the copolymer (B-1)
was 1.93 (meq/g) per 1 g of the copolymer (B-1) assuming all the
carboxyl groups in the copolymer (B-1) to be in unneutralized
forms. In addition, the average molecular weight (Y) of the
polyalkylene glycol chain portion, as calculated from the
structures of the used monomers, was 1,173.
Production Example 2 (Production of Copolymer (B-2))
[0109] First of all, 847.7 parts of ion-exchanged water was placed
into the same reactor as that used in Production Example 1. The
internal air of the reactor was then replaced with nitrogen under
stirring, and the reactor was then heated to 80.degree. C. under
the nitrogen atmosphere. Next, an aqueous monomer solution, as
prepared by mixing 275.6 parts of 1-butoxypolyethylene glycol
monomethacrylate (average molar number of addition of ethylene
oxide: 75), 24.4 parts of methacrylic acid, 200 parts of
ion-exchanged water, and 2.3 parts of 3-mercaptopropionic acid
(chain transfer agent), was dropwise added into the reactor over a
period of 4 hours, and simultaneously with the initiation of this
dropwise addition of the aqueous monomer solution, an aqueous
initiator solution comprising 3.4 parts of ammonium persulfate and
146.6 parts of ion-exchanged water was dropwise added into the
reactor over a period of 5 hours. Subsequently to the end of the
dropwise addition of the aqueous initiator solution, the internal
temperature of the reactor was maintained at 80.degree. C. for 1
hour to complete the polymerization reaction. Thereafter, the
resultant reaction mixture was neutralized with a 30% aqueous
sodium hydroxide solution, thus obtaining an aqueous solution of a
copolymer (B-2) having a weight-average molecular weight of 38,000.
Incidentally, the milliequivalent number of carboxyl groups in the
copolymer (B-2) was 0.95 (meq/g) per 1 g of the copolymer (B-2)
assuming all the carboxyl groups in the copolymer (B-2) to be in
unneutralized forms. In addition, the average molecular weight (Y)
of the polyalkylene glycol chain portion, as calculated from the
structures of the used monomers, was 3,373.
Production Example 3 (Production of Copolymer (B-3))
[0110] First of all, 1,698 parts of ion-exchanged water was placed
into the same reactor as that used in Production Example 1. The
internal air of the reactor was then replaced with nitrogen under
stirring, and the reactor was then heated to 80.degree. C. under
the nitrogen atmosphere. Next, an aqueous monomer solution, as
prepared by mixing 1,668 parts of methoxypolyethylene glycol
monomethacrylate (average molar number of addition of ethylene
oxide: 25), 332 parts of methacrylic acid, 500 parts of
ion-exchanged water, and 16.7 parts of 3-mercaptopropionic acid
(chain transfer agent), was dropwise added into the reactor over a
period of 4 hours, and simultaneously with the initiation of this
dropwise addition of the aqueous monomer solution, an aqueous
initiator solution comprising 23 parts of ammonium persulfate and
207 parts of ion-exchanged water was dropwise added into the
reactor over a period of 5 hours. Subsequently to the end of the
dropwise addition of the aqueous initiator solution, the internal
temperature of the reactor was maintained at 80.degree. C. for 1
hour to complete the polymerization reaction. Thereafter, the
resultant reaction mixture was neutralized with a 30% aqueous
sodium hydroxide solution, thus obtaining an aqueous solution of a
copolymer (B-3) having a weight-average molecular weight of 24,000.
Incidentally, the milliequivalent number of carboxyl groups in the
copolymer (B-3) was 1.93 (meq/g) per 1 g of the copolymer (B-3)
assuming all the carboxyl groups in the copolymer (B-3) to be in
unneutralized forms. In addition, the average molecular weight (Y)
of the polyalkylene glycol chain portion, as calculated from the
structures of the used monomers, was 1,131.
EXAMPLES 1 to 10
Comparative Examples 1 to 8
[0111] An amount of 400 g of normal portland cement (produced by
Pacific Cement Co., Ltd.) and 800 g of Toyoura standard sand were
kneaded without water at a low speed for 30 seconds using a HOBART
type mortar mixer (N-50 model, produced by HOBART Corporation). The
aforementioned polyalkylene glycol (A) and the aforementioned
copolymer (B) were weighed out in the ratios of Tables 1 and 2 and
then diluted with ion-exchanged water to the total weight of 240 g,
and the resultant mixture was added to the above-kneaded
cement-sand mixture. Then, the resultant mixture was kneaded at a
middle speed for 3 minutes, thus obtaining mortar. Incidentally,
the mixing ratio (%) of each component in the Tables is weight %
(in terms of solid content), based on cement, of each
component.
[0112] The resultant mortar was evaluated in the following
ways:
Fluidity (Mortar Flow Value)
[0113] The resultant mortar was fully filled into a hollow cylinder
of 55 mm both in inner diameter and in height as placed on a
horizontal table. After 5 minutes from the kneading initiation,
this cylinder was gently lifted in perpendicular, and the major and
minor axes of the mortar as spread onto the table were measured,
and the average value thereof was regarded as the mortar flow value
(mm). Incidentally, if the quantity of entrained air is large, the
flow value and the shrinkage amount both result in being apparently
large. Therefore, the quantity of air was adjusted to 5.+-.1% by
fitly using a (oxyalkylene-based) defoaming agent for the quantity
of entrained air to be a definite value. The results are shown in
Tables 1 and 2. Incidentally, it can be said that: the larger this
mortar flow value (mm) is, the higher the fluidity is.
Shrinkage Reducibility (Change of Length)
[0114] First, a specimen (4.times.4.times.16 cm) was prepared
according to JIS-A-1129 as follows. The mold frame was precoated
with silicone grease for the purposes of water cutting and easy
mold releasing, and an arrangement was carried out so that a gauge
plug might be fitted on both sides of the specimen. Then, the
mortar as obtained above was cast into this mold frame, and the
resultant mortar-containing mold frame was then placed into an
thermohumidistat (PL-2G, produced by Tabai Espec Co., Ltd.) as set
at a temperature of 20.degree. C. and a humidity of 60%, whereby
initial curing was carried out. After 4 days, the resultant
specimen was released from the mold frame, and the silicone grease
as attached to the surface of the specimen was washed off with
water using a sponge-made scrubbing brush. Thereafter, specimen was
cured in still water of 20.degree. C. for 7 days.
[0115] Water was wiped off from the surface of the specimen (as
cured above in still water for 7 days) with a paper towel, and
immediately thereafter the length of the specimen was measured with
a dial gauge (produced by Nishi Nihon Shikenki Co., Ltd.) in
accordance with JIS-A-1129, and the length at this time was taken
as the standard. Thereafter, the specimen was preserved in the
thermohumidistat as set at a temperature of 20.degree. C. and a
humidity of 60%. After 28 days from the ending date of the curing
in water, the length was measured again to determine a change of
length, namely, a difference (.mu.m) as given by subtracting a
length of the specimen 28 days after the standard date (ending date
of the curing in water) from a length of the specimen at the
standard date (for example, the case where the change of length is
247 .mu.m shows that the specimen shrank by 247 .mu.m from its
length at the standard date). The results are shown in Tables 1 and
2. Incidentally, it can be said that: the less the value of the
change of length (.mu.m) is, the greater the shrinkage reduction
effect is and the less the structure cracked due to shrinkage.
1 TABLE 1 Average A/B molecular Change of (weight Component
Component Total (%) weight Mortar flow length Mixing ratio) A (%) B
(%) of A + B ratio X/Y value (mm) (.mu.m) Example A-1 + 0.05 0.0214
0.4286 0.4500 1.0 135 247 1 B-1 Example A-1 + 0.10 0.0409 0.4091
0.4500 1.0 130 237 2 B-1 Example A-1 + 0.20 0.0750 0.3750 0.4500
1.0 125 218 3 B-1 Example A-2 + 0.05 0.0152 0.3048 0.3200 1.0 144
249 4 B-2 Example A-2 + 0.10 0.0291 0.2909 0.3200 1.0 139 242 5 B-2
Example A-2 + 0.20 0.0533 0.2667 0.3200 1.0 132 225 6 B-2 Example
A-3 + 0.02 0.0047 0.2353 0.2400 1.0 142 256 7 B-3 Example A-3 +
0.05 0.0114 0.2286 0.2400 1.0 140 252 8 B-3 Example A-3 + 0.10
0.0218 0.2182 0.2400 1.0 136 246 9 B-3 Example A-3 + 0.20 0.0400
0.2000 0.2400 1.0 130 232 10 B-3
[0116]
2 TABLE 2 Average A/B molecular Change of (weight Component
Component Total (%) weight Mortar flow length Mixing ratio) A (%) B
(%) of A + B ratio X/Y value (mm) (.mu.m) Comparative B-1 0.00
0.0000 0.4500 0.4500 -- 139 260 Example 1 Comparative A-1 + 0.35
0.1167 0.3333 0.4500 1.0 103 193 Example 2 B-1 Comparative B-2 0.00
0.0000 0.3200 0.3200 -- 147 263 Example 3 Comparative A-2 + 0.35
0.0830 0.2370 0.3200 1.0 107 202 Example 4 B-2 Comparative B-3 0.00
0.0000 0.2400 0.2400 -- 145 262 Example 5 Comparative A-3 + 0.005
0.0012 0.2388 0.2400 1.0 143 261 Example 6 B-3 Comparative A-3 +
0.35 0.0622 0.1778 0.2400 1.0 110 213 Example 7 B-3 Comparative A-4
+ 0.20 0.0400 0.2000 0.2400 0.2 128 259 Example 8 B-3
[0117] From Table 2, it has been found as follows. As to
Comparative Examples 1, 3, 5, and 6, the fluidity is high, but the
shrinkage reduction effect is not obtained enough, because the
mixing ratio of the component A is too low when compared with the
range as defined in the present invention. On the other hand, as to
Comparative Examples 2, 4, and 7, the shrinkage reduction effect is
great, but the fluidity is not obtained enough, because the mixing
ratio of the component A is too high when compared with the range
as defined in the present invention. In addition, as to Comparative
Example 8, the fluidity is high, but the shrinkage reduction effect
is not obtained enough, because the average molecular weight (X) of
the component A is too low when compared with the average molecular
weight (Y) of the polyalkylene glycol chain portion of the
component B.
[0118] In contrast to the above, from Table 1, it has been found
that all the Examples of the cement composition according to the
present invention display excellent shrinkage reducibility and
excellent fluidity.
[0119] Various details of the invention may be changed without
departing from its spirit not its scope. Furthermore, the foregoing
description of the preferred embodiments according to the present
invention is provided for the purpose of illustration only, and not
for the purpose of limiting the invention as defined by the
appended claims and their equivalents.
* * * * *