U.S. patent application number 11/388046 was filed with the patent office on 2007-09-06 for additive building material mixtures containing solid microparticles.
This patent application is currently assigned to ROEHM GMBH & CO. KG. Invention is credited to Holger Kautz, Gerd Lohden, Jan Hendrik Schattka.
Application Number | 20070204544 11/388046 |
Document ID | / |
Family ID | 37872328 |
Filed Date | 2007-09-06 |
United States Patent
Application |
20070204544 |
Kind Code |
A1 |
Kautz; Holger ; et
al. |
September 6, 2007 |
Additive building material mixtures containing solid
microparticles
Abstract
The present invention relates to the use of compact polymeric
microparticles in hydraulically setting building material mixtures
for the purpose of enhancing their frost resistance and cyclical
freeze/thaw durability.
Inventors: |
Kautz; Holger; (Hanau,
DE) ; Schattka; Jan Hendrik; (Hanau, DE) ;
Lohden; Gerd; (Hanau, DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
ROEHM GMBH & CO. KG
Darmstadt
DE
|
Family ID: |
37872328 |
Appl. No.: |
11/388046 |
Filed: |
March 24, 2006 |
Current U.S.
Class: |
52/309.17 ;
106/802; 428/402; 524/8 |
Current CPC
Class: |
C04B 16/085 20130101;
C04B 16/085 20130101; C04B 24/2641 20130101; C04B 2103/0057
20130101; Y10T 428/2982 20150115; C04B 28/02 20130101; C04B
2103/0049 20130101; C04B 2103/0058 20130101; C04B 2111/29 20130101;
C04B 28/02 20130101 |
Class at
Publication: |
52/309.17 ;
524/8; 106/802; 428/402 |
International
Class: |
E04C 1/00 20060101
E04C001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 1, 2006 |
DE |
10 2006 009 840.4 |
Claims
1. A hydraulically setting building material mixture, consisting
essentially of: a hydraulically setting building material: and
polymeric microparticles which are synthesized in one or more
stages from at least one ethylenically unsaturated monomer; wherein
said polymeric microparticles are in the form of spray-dried,
coagulated or freeze-dried powder: and wherein said ethylenically
unsaturated monomer is selected from the group consisting of
nitriles of (meth)acrylic acid, nitrogen-containing methacrylates,
carbonyl-containing methacrylates, glycol dimethacrylates,
methacrylates of ether alcohols, oxiranyl methacrylates,
phosphorus-containing methacrylates, boron-containing
methacrylates, silicon-containing methacrylates, sulfur-containing
methacrylates, vinyl esters, styrene, substituted styrenes with an
alkyl substituent in the side chain, heterocyclic vinyl compounds,
vinyl ethers, isoprenyl ethers, maleic acid compounds, fumaric acid
compounds, .alpha.-olefins and mixtures thereof.
2. The hydraulically setting building material mixture according to
claim 1, wherein the ethylenically unsaturated monomer is selected
from the group consisting of styrene, butadiene, vinyltoluene,
ethylene, propylene, vinyl acetate, vinyl chloride, vinylidene
chloride, acrylonitrile, acrylamide, methacrylamide,
C.sub.1-C.sub.18 alkyl esters of acrylic acid, C.sub.1-C.sub.18
alkyl esters of methacrylic acid, and mixtures thereof.
3. The hydraulically setting building material mixture according to
claim 1, wherein said polymeric microparticles further comprise at
least one crosslinker.
4. The hydraulically setting building material mixture according to
claim 3, wherein said crosslinker is selected from the group
consisting ethylene glycol di(meth)acrylate, propylene glycol
di(meth)acrylate, allyl (meth)acrylate, divinylbenzene,
diallylmaleate, trimethylolpropane trimethacrylate, glycerol
dimethacrylate, glycerol trimethacrylate, pentaerythritol
tetramethacrylate, and mixtures thereof.
5. The hydraulically setting building material mixture according to
claim 1, wherein the said polymeric microparticles are in the form
of a dispersion.
6. The hydraulically setting building material mixture according to
claim 1 wherein said polymeric microparticles are in the form of
spray-dried, coagulated or freeze-dried powder.
7. The hydraulically setting building material mixture according to
claim 1, wherein the polymeric microparticles have an average
particle size of 10 to 5000 nm.
8. The hydraulically setting building material mixture according to
claim 1, wherein the polymeric microparticles are used in an amount
of 0.01% to 5% by volume, based on the volume of the building
material mixture.
9. The hydraulically setting building material mixture according to
claim 1, wherein the polymeric microparticles are used in an amount
of 0.1% to 0.5% by volume, based on the volume of the building
material mixture.
10. The hydraulically setting building material mixture according
to claim 1, further comprising a binder selected from the group
consisting of cement, lime, gypsum anhydrite and mixtures
thereof.
11. The hydraulically setting building material mixture according
to claim 1, which comprises concrete or mortar.
12. A method of producing a hydraulically setting building material
mixture, comprising: adding polymeric microparticles to a setting
building material, wherein said polymeric microparticles are
synthesized in one or more stages from at least one ethylenically
unsaturated monomer; wherein said polymeric microparticles are in
the form of spray-dried, coagulated or freeze-dried powder, wherein
said hydraulically setting building material mixture consists
essentially of said polymeric microparticles and said setting
building material; and wherein said ethylenically unsaturated
monomer is selected from the group consisting of nitriles of
(meth)acrylic acid, nitrogen-containing methacrylates,
carbonyl-containing methacrylates, glycol dimethacrylates,
methacrylates of ether alcohols, oxiranyl methacrylates,
phosphorus-containing methacrylates, boron-containing
methacrylates, silicon-containing methacrylates, sulfur-containing
methacrylates, vinyl esters, styrene, substituted styrenes with an
alkyl substituent in the side chain, heterocyclic vinyl compounds,
vinyl ethers, isoprenyl ethers, maleic acid compounds, fumaric acid
compounds, .alpha.-olefins and mixtures thereof.
13. The method according to claim 1, wherein the ethylenically
unsaturated monomer is selected from the group consisting of
styrene, butadiene, vinyltoluene, ethylene, propylene, vinyl
acetate, vinyl chloride, vinylidene chloride, acrylonitrile,
acrylamide, methacrylamide, C.sub.1-C.sub.18 alkyl esters of
acrylic acid, C.sub.1-C.sub.18 alkyl esters of methacrylic acid,
and mixtures thereof.
14. The method according to claim 1, wherein said polymeric
microparticles further comprise at least one crosslinker.
15. The method according to claim 14, wherein said crosslinker is
selected from the group consisting of ethylene glycol
di(meth)acrylate, propylene glycol di (meth)acrylate, allyl
(meth)acrylate, divinylbenzene, diallylmaleate, trimethylolpropane
trimethacrylate, glycerol dimethacrylate, glycerol trimethacrylate,
pentaerythritol tetramethacrylate, and mixtures thereof.
16. The method according to claim 1, wherein said polymeric
microparticles are in the form of a dispersion.
17. The method according to claim 1, wherein said polymeric
microparticles are in the form of spray-dried, coagulated or
freeze-dried powder.
18. The method according to claim 1, wherein the polymeric
microparticles have an average particle size of 10 to 5000 nm.
19. The method according to claim 1, wherein the polymeric
microparticles are used in an amount of 0.01% to 5% by volume,
based on the volume of the building material mixture.
20. The method according to claim 1, wherein the polymeric
microparticles are used in an amount of 0.1% to 0.5% by volume,
based on the volume of the building material mixture.
21. The method according to claim 1, further comprising a binder
selected from the group consisting of cement, lime, gypsum
anhydrite and mixtures thereof.
22. The method according to claim 1, which comprises concrete or
mortar.
23. A hydraulically setting building material mixture, comprising:
a hydraulically setting building material; and polymeric
microparticles which are synthesized in one or more stages from at
least one ethylenically unsaturated monomer; wherein said polymeric
microparticles are homogeneously distributed in said mixture; and
wherein capillary-active pores have an average spacing from one
another which is smaller than a power spacing factor.
Description
[0001] The present invention relates to the use of polymeric
microparticles in hydraulically setting building material mixtures
for the purpose of enhancing their frost resistance and cyclical
freeze/thaw durability.
[0002] Concrete is an important building material and is defined by
DIN 1045 (07/1988) as artificial stone formed by hardening from a
mixture of cement, aggregate and water, together where appropriate
with concrete admixtures and concrete additions. One way in which
concrete is classified is by its subdivision into strength groups
(BI-BII) and strength classes (B5-B55). Adding gas-formers or
foam-formers to the mix produces aerated concrete or foamed
concrete (Rompp Lexikon, 10th ed., 1996, Georg Thieme Verlag).
[0003] Concrete has two time-dependent properties. Firstly, by
drying out, it undergoes a reduction in volume that is termed
shrinkage. The majority of the water, however, is bound in the form
of water of crystallization. Concrete, rather than drying, sets:
that is, the initially highly mobile cement paste (cement and
water) starts to stiffen, becomes rigid, and, finally, solidifies,
depending on the timepoint and progress of the
chemical/mineralogical reaction between the cement and the water,
known as hydration. As a result of the water-binding capacity of
the cement it is possible for concrete, unlike quicklime, to harden
and remain solid even under water. Secondly, concrete undergoes
deformation under load, known as creep.
[0004] The freeze/thaw cycle refers to the climatic alternation of
temperatures around the freezing point of water. Particularly in
the case of mineral-bound building materials such as concrete, the
freeze/thaw cycle is a mechanism of damage. These materials possess
a porous, capillary structure and are not watertight. If a
structure of this kind that is full of water is exposed to
temperatures below 0.degree. C., then the water freezes in the
pores. As a result of the density anomaly of water, the ice then
expands. This results in damage to the building material. Within
the very fine pores, as a result of surface effects, there is a
reduction in the freezing point. In micropores water does not
freeze until below -17.degree. C. Since, as a result of freeze/thaw
cycling, the material itself also expands and contracts, there is
additionally a capillary pump effect, which further increases the
absorption of water and hence, indirectly, the damage. The number
of freeze/thaw cycles is therefore critical with regard to
damage.
[0005] Decisive factors affecting the resistance of concrete to
frost and to cyclical freeze/thaw under simultaneous exposure to
thawing agents; are the imperviousness of its microstructure, a
certain strength of the matrix, and the presence of a certain pore
microstructure. The microstructure of a cement-bound concrete is
traversed by capillary pores (radius: 2 .mu.m-2 mm) and gel pores
(radius: 2-50 nm). Water present in these pores differs in its
state as a function of the pore diameter. Whereas water in the
capillary pores retains its usual properties, that in the gel pores
is classified as condensed water (mesopores: 50 nm) and
adsorptively bound surface water (micropores: 2 nm), the freezing
points of which may for example be well below -50.degree. C. [M. J.
Setzer, Interaction of water with hardened cement paste, Ceramic
Transactions 16 (1991) 415-39]. Consequently, even when the
concrete is cooled to low temperatures, some of the water in the
pores remains unfrozen (metastable water). For a given temperature,
however, the vapor pressure over ice is lower than that over water.
Since ice and metastable water are present alongside one another
simultaneously, a vapor-pressure gradient develops which leads to
diffusion of the still-liquid water to the ice and to the formation
of ice from said water, resulting in removal of water from the
smaller pores or accumulation of ice in the larger pores. This
redistribution of water as a result of cooling takes place in every
porous system and is critically dependent on the type of pore
distribution.
[0006] The artificial introduction of microfine air pores in the
concrete hence gives rise primarily to what are called expansion
spaces for expanding ice and ice-water. Within these pores,
freezing water can expand or internal pressure and stresses of ice
and ice-water can be absorbed without formation of microcracks and
hence without frost damage to the concrete. The fundamental way in
which such air-pore systems act has been described, in connection
with the mechanism of frost damage to concrete, in a large number
of reviews [Schulson, Erland M. (1998) Ice damage to concrete.
CRREL Special Report 98-6; S. Chatterji, Freezing of air-entrained
cement-based materials and specific actions of air-entraining
agents, Cement & Concrete Composites 25 (2003) 759-65; G. W.
Scherer, J. Chen & J. Valenza, Methods for protecting concrete
from freeze damage, U.S. Pat. No. 6,485,560 B1 (2002); M. Pigeon,
B. Zuber & J. Marchand, Freeze/thaw resistance, Advanced
Concrete Technology 2 (2003) 11/1-11/17; B. Erlin & B. Mather,
A new process by which cyclic freezing can damage concrete--the
Erlin/Mather effect, Cement & Concrete Research 35 (2005)
1407-11].
[0007] A precondition for improved resistance of the concrete on
exposure to the freezing and thawing cycle is that the distance of
each point in the hardened cement from the next artificial air pore
does not exceed a defined value. This distance is also referred to
as the "Powers spacing factor" [T. C. Powers, The air requirement
of frost-resistant concrete, Proceedings of the Highway Research
Board 29 (1949) 184-202]. Laboratory tests have shown that
exceeding the critical "Power spacing factor" of 500 .mu.m leads to
damage to the concrete in the freezing and thawing cycle. In order
to achieve this with a limited air-pore content, the diameter of
the artificially introduced air pores must therefore be less than
200-300 .mu.m [K. Snyder, K. Natesaiyer & K. Hover, The
stereological and statistical properties of entrained air voids in
concrete: A mathematical basis for air void systems
characterization, Materials Science of Concrete VI (2001)
129-214].
[0008] The formation of an artificial air-pore system depends
critically on the composition and the conformity of the aggregates,
the type and amount of the cement, the consistency of the concrete,
the mixer used, the mixing time, and the temperature, but also on
the nature and amount of the agent that forms the air pores, the
air entrainer. Although these influencing factors can be controlled
if account is taken of appropriate production rules, there may
nevertheless be a multiplicity of unwanted adverse effects,
resulting ultimately in the concrete's air content being above or
below the desired level and hence adversely affecting the strength
or the frost resistance of the concrete.
[0009] Artificial air pores of this kind cannot be metered
directly; instead, the air entrained by mixing is stabilized by the
addition of the aforementioned air entrainers [L. Du & K. J.
Folliard, Mechanism of air entrainment in concrete, Cement &
Concrete Research 35 (2005) 1463-71]. Conventional air entrainers
are mostly surfactant-like in structure and break up the air
introduced by mixing into small air bubbles having a diameter as
far as possible of less than 300 .mu.m, and stabilize them in the
wet concrete microstructure. A distinction is made here between two
types.
[0010] One type--for example sodium oleate, the sodium salt of
abietic acid or Vinsol resin, an extract from pine roots--reacts
with the calcium hydroxide of the pore solution in the cement paste
and is precipitated as insoluble calcium salt. These hydrophobic
salts reduce the surface tension of the water and collect at the
interface between cement particle, air and water. They stabilize
the microbubbles and are therefore encountered at the surfaces of
these air pores in the concrete as it hardens. The other type--for
example sodium lauryl sulfate (SDS) or sodium
dodecylphenylsulfonate--reacts with calcium hydroxide to form
calcium salts which, in contrast, are soluble, but which exhibit an
abnormal solution behavior. Below a certain critical temperature
the solubility of these surfactants is very low, while above this
temperature their solubility is very good. As a result of
preferential accumulation at the air/water boundary they likewise
reduce the surface tension, thus stabilize the microbubbles, and
are preferably encountered at the surfaces of these air pores in
the hardened concrete.
[0011] The use of these prior-art air entrainers is accompanied by
a host of problems [L. Du & K. J. Folliard, Mechanism of air
entrainment in concrete, Cement & Concrete Research 35 (2005)
1463-71]. For example, prolonged mixing times, different mixer
speeds and altered metering sequences in the case of ready-mix
concretes result in the expulsion of the stabilized air (in the air
pores).
[0012] The transporting of concretes with extended transport times,
poor temperature control and different pumping and conveying
equipment, and also the introduction of these concretes in
conjunction with altered subsequent processing, jerking and
temperature conditions, can produce a significant change in an
air-pore content set beforehand. In the worst case this may mean
that a concrete no longer complies with the required limiting
values of a certain exposure class and has therefore become
unusable [EN 206-1 (2000), Concrete--Part 1: Specification,
performance, production and conformity].
[0013] The amount of fine substances in the concrete (e.g. cement
with different alkali content, additions such as flyash, silica
dust or color additions) likewise adversely affects air
entrainment. There may also be interactions with flow improvers
that have a defoaming action, and hence expel air pores, but may
also introduce them in an uncontrolled manner.
[0014] A relatively new possibility for improving the frost
resistance and cyclical freeze/thaw durability is to achieve the
air content by the admixing or solid metering of polymeric
microparticles (hollow microspheres) [H. Sommer, A new method of
making concrete resistant to frost and de-icing salts, Betonwerk
& Fertigteiltechnik 9 (1978) 476-84]. Since the microparticles
generally have particle sizes of less than 100 .mu.m, they can also
be distributed more finely and uniformly in the concrete
microstructure than can artificially introduced air pores.
Consequently, even small amounts are sufficient for sufficient
resistance of the concrete to the freezing and thawing cycle. The
use of polymeric microparticles of this kind for improving the
frost resistance and cyclical freeze/thaw durability of concrete is
already known from the prior art [cf. DE 2229094 A1, U.S. Pat. No.
4,057,526 B1, U.S. Pat. No. 4,082,562 B1, DE 3026719 A1]. The
microparticles described therein are notable in particular for the
fact that they possess a void smaller than 200 .mu.m (in diameter)
and that this hollow core consists of air (or a gaseous substance).
This likewise includes porous microparticles from the 100 .mu.m
scale, which may possess a multiple of relatively small voids
and/or pores.
[0015] Compact polymeric microparticles have not been considered to
date in practice for the purpose of enhancing the frost resistance
and cyclical freeze/thaw durability.
[0016] For the hollow microspheres, however, relatively high levels
of addition are needed in order to obtain values below the critical
"Power spacing factor", the reason for this lying at least partly
in the large particle diameter of >100 .mu.m. This fact, in
combination with the high preparation costs, a result of the
multistage preparation processes, have been detrimental to the
establishment of these technologies on the market.
[0017] The object on which the present invention is based,
therefore, was to provide a means of improving the frost resistance
and cyclical freeze/thaw durability for hydraulically setting
building material mixtures that develops its full activity even at
relatively low levels of addition, and which, moreover, can be
prepared easily and inexpensively. A further object was not, or not
substantially, to impair the mechanical strength of the building
material mixture as a result of said means.
[0018] It has now been found, surprisingly, that compact polymeric
microparticles of single-stage or multistage synthesis are also
suitable for improvements to the frost resistance and/or cyclical
freeze/thaw durability for hydraulically setting building material
mixtures. By microparticles of single-stage synthesis are meant a
particle (without a shell) which is synthesized homogeneously in
the composition. This is all the more surprising since these
polymeric microparticles do not entrain any air into the
construction mixture.
[0019] The mode of action can be explained as follows: the
polymeric microparticles of the invention are in homogeneous
distribution in the construction mixture. A cavity between
microparticle and cured construction mixture, which possibly
becomes further enlarged as a result of the contraction of the
construction mixture on curing, serves as an expansion site for
freezing water. The uniform distribution of these capillary-active
pores, with an average spacing from one another which is smaller
than the "Power spacing factor", then provides for the increase in
frost resistance and/or cyclical freeze/thaw durability.
[0020] Through the use of the polymeric formations of the invention
it is possible to keep the introduction of air into the building
material mixture at an extraordinarily low level. As a result,
markedly improved compressive strengths are achievable in the
concrete. Consequently it is possible to achieve strength classes
which can be set otherwise only by means of a substantially lower
water/cement value (w/c value). Low w/c values, however, in turn
considerably restrict the processability of the concrete in certain
circumstances. Higher compressive strengths are of interest, in
addition and in particular, insofar as it is possible to reduce the
cement content of the concrete, which is needed for strength to
develop, as a result of which it is possible to achieve a
significant lowering in the price per m.sup.3 of concrete.
[0021] The polymeric microparticles comprise at least one
monoethylenically unsaturated monomer. The microparticles may be
single-stage or multistage, and the comonomer composition of the
individual stages may be different. Preferably included are, among
others, nitriles of (meth)acrylic acid, and other
nitrogen-containing methacrylates, such as
methacryloylamidoacetonitrile,
2-methacryloyloxyethylmethylcyanamide, cyanomethyl methacrylate;
carbonyl-containing methacrylates, such as oxazolidinylethyl
methacrylate, N-(methacryloyloxy)formamide, acetonyl methacrylate,
N-methacryloyl-morpholine, N-methacryloyl-2-pyrrolidonone; glycol
dimethacrylates, such as 1,4-butanediol methacrylate, 2-butoxyethyl
methacrylate, 2-ethoxyethoxymethyl methacrylate, 2-ethoxyethyl
methacrylate, methacrylates of ether alcohols, such as
tetrahydrofurfuryl methacrylate, vinyloxyethoxyethyl methacrylate,
methoxy-ethoxyethyl methacrylate, 1-butoxypropyl methacrylate,
1-methyl-(2-vinyloxy)-ethyl methacrylate, cyclohexyloxymethyl
methacrylate, methoxymethoxyethyl methacrylate, benzyloxymethyl
methacrylate, furfuryl methacrylate, 2-butoxy-ethyl methacrylate,
2-ethoxyethoxymethyl methacrylate, 2-ethoxyethyl methacrylate,
allyloxymethyl methacrylate, 1-ethoxybutyl methacrylate,
methoxymethyl methacrylate, 1-ethoxyethyl methacrylate,
ethoxymethyl methacrylate; oxiranyl methacrylates, such as
2,3-epoxybutyl methacrylate, 3,4-epoxybutyl methacrylate, glycidyl
methacrylate; phosphorus-, boron-and/or silicon-containing
methacrylates, such as 2-(dimethylphosphato)propyl methacrylate,
2-(ethylenephosphito)propyl methacrylate, dimethylphosphino-methyl
methacrylate, dimethylphosphonoethyl methacrylate, diethyl
methacryloylphosphonate, dipropyl methacryloyl phosphate;
sulfur-containing methacrylates, such as ethylsulfinylethyl
methacrylate, 4-thiocyanatobutyl methacrylate, ethylsulfonylethyl
methacrylate, thiocyanatomethyl methacrylate, methylsulfinylmethyl
methacrylate, and bis(methacryloyloxyethyl) sulfide; vinyl esters,
such as vinyl acetate;
[0022] styrene, substituted styrenes with an alkyl substituent in
the side chain, such as *methylstyrene and *ethylstyrene, for
example, substituted styrenes with an alkyl substituent on the
ring, such as vinyl toluene and p-methylstyrene;
[0023] heterocyclic vinyl compounds, such as 2-vinylpyridine,
3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine,
2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine,
9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole,
1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinyl-pyrrolidone,
2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine,
N-vinyl-caprolactam, N-vinylbutyrolactam, vinyloxolane, vinylfuran,
vinylthiophene, vinylthiolane, vinylthiazoles and hydrogenated
vinylthiazoles, vinyloxazoles and hydrogenated vinyloxazoles;
[0024] vinyl and isoprenyl ethers;
[0025] maleic acid derivatives, such as diesters of maleic acid,
the alcohol residues having 1 to 9 carbon atoms, maleic anhydride,
methylmaleic anhydride, maleimide, and methylmaleimide;
[0026] fumaric acid derivatives, such as diesters of fumaric acid,
the alcohol residues having 1 to 9 carbon atoms;
[0027] .alpha.-olefins such as ethene, propene, n-butene,
isobutene, n-pentene, isopentene, n-hexene, isohexene;
cyclohexene.
[0028] In addition it has been found that by means of corresponding
monomers it is possible to bring about, in addition to the ionic
repulsion, the steric repulsion of the polymeric formations as
well. This leads to an additional stabilization of the polymeric
formations in the dispersion and the construction mixture.
[0029] In accordance with the invention it is therefore also
possible to use free-radically polymerizable monomers having a
molar mass of greater than 200 g/mol which carry a hydrophilic
radical. Particular preference is given to monomers which carry a
polyethylene oxide block having two or more units of ethylene
oxide. Preference is given to using monomers from the group of
(meth)acrylic esters of methoxypoiyethyiene glycol
CH.sub.3O(CH.sub.2CH.sub.2O).sub.nH, (with n=2), (meth)acrylic
esters of an ethoxylated C16-C18 fatty alcohol mixture (with 2 or
more ethylene oxide units), methacrylic esters of
5-tert-octylphenoxypolyethoxyethanol (with 2 or more ethylene oxide
units), nonylphenoxypolyethoxyethanol (with 2 or more ethylene
oxide units) or mixtures thereof.
[0030] In addition there may be one or more monoethylenically
unsaturated monomers containing an acid group present. Preference
is given to acrylic acid, methacrylic acid, ethacrylic acid,
a-chloroacrylic acid, a-cyanoacrylic acid, p-methylacrylic acid
(crotonic acid), a-phenylacrylic acid, p-acryloyloxypropionic acid,
sorbic acid, a-chlorosorbic acid, 2'-methylisocrotonic acid,
cinnamic acid, p-chlorocinnamic acid, p-stearylic acid, itaconic
acid, citraconic acid, mesacronic acid, glutaconic acid, aconitic
acid, maleic acid, fumaric acid, tricarboxyethylene, and maleic
anhydride, hydroxyl-or amino-containing esters of the above acids,
preferably of acrylic or methacrylic acid, such as 2-hydroxyethyl
acrylate, N,N-dimethylaminoethyl acrylate, and the analogous
derivatives of methacrylic acid, particular preference being given
to acrylic acid and also methacrylic acid and preference beyond
that to acrylic acid.
[0031] In addition to the monoethylenically unsaturated monomer
containing an acid group, this polymer may also be based on further
comonomers other than the monoethylenically unsaturated monomer
containing an acid group. Preferred comonomers are ethylenically
unsaturated sulfonic acid monomers, ethylenically unsaturated
phosphonic acid monomers, and acrylamides, preferably.
[0032] Ethylenically unsaturated sulfonic acid monomers are
preferably aliphatic or aromatic vinylsulfonic acids or acrylic or
methacrylic sulfonic acids. Preferred aliphatic or aromatic
vinylsulfonic acids are vinylsulfonic acid, allylsulfonic acid,
4-vinylbenzylsulfonic acid, vinyltoluenesulfonic acid, and
styrenesulfonic acid. Preferred acryloyl-and methacryloylsulfonic
acids are sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl
acrylate, sulfopropyl methacrylate,
2-hydroxy-3-methacryloyloxypropylsulfonic acid, and
2-acrylamido-2-methyl-propanesulfonic acid.
[0033] Ethylenically unsaturated phosphonic acid monomers such as
vinylphosphonic acid, allylphosphonic acid, vinylbenzylphosphonic
acid, acrylamidoalkylphosphonic acids, acrylamidoalkyldiphosphonic
acids. Phosphonomethylated vinylamines, (meth)acryloylphosphonic
acid derivatives.
[0034] Possible acrylamides are alkyl-substituted acrylamides or
aminoalkyl-substituted derivatives of acrylamide or of
methacrylamide, such as N-vinyl-amides, N-vinylformamides,
N-vinylacetamides, N-vinyl-N-methylacetamides,
N-vinyl-N-methylformamides, N-methylol(meth)acrylamide,
vinylpyrrolidone, N,N-dimethylpropylacrylamide, dimethylacrylamide
or diethylacrylamide, and the corresponding methacrylamide
derivatives, and also acrylamide and methacrylamide, preference
being given to acrylamide.
[0035] The chemical crosslinking can be achieved by crosslinkers
generally known to the skilled worker. The crosslinkers may be
present in any state. Inventively preferred crosslinkers are
polyacrylic or polymethacrylic esters, which are obtained, for
example, through the reaction of a polyol or ethoxylated polyol
such as ethylene glycol, propylene glycol, trimethylolpropane,
1,6-hexanediol-glycerol, pentaerythritol, polyethylene glycol or
polypropylene glycol with acrylic acid or methacrylic acid. Use may
also be made of polyols, amino alcohols and also their
mono(meth)acrylic esters, and monoallyl ethers. Additionally also
acrylic esters of monoallyl compounds of the polyols and amino
alcohols. Another group of crosslinkers is obtained through the
reaction of polyalkylenepolyamines such as diethylenetriamine and
triethylenetetra-aminemethacrylic acid or methacrylic acid.
Suitable crosslinkers include 1,4-butanediol diacrylate,
1,4-butanediol dimethacrylate, 1,3-butylene glycol diacrylate,
1,3-butylene glycol dimethacrylate, diethylene glycol diacrylate,
diethylene glycol dimethacrylate, ethoxylated bisphenol A
diacrylate, ethoxylated bisphenol A dimethacrylate, ethylene glycol
dimethacrylate, 1,6-hexanedioi diacrylate, 1,6-hexanediol
dimethacrylate, neopentyl glycol dimethacrylate, polyethylene
glycol diacrylate, polyethylene glycol dimethacrylate, triethylene
glycol diacrylate, triethylene glycol dimethacrylate, tripropylene
glycol diacrylate, tetraethylene glycol diacrylate, tetraethylene
glycol diacrylate, tetraethylene glycol dimethacrylate,
dipentaerythritol pentaacrylate, pentaerythritol tetraacrylate,
pentaerythritol triacrylate, trimethylolpropane triacrylate,
trimethylol trimethacrylate,
tris(2-hydroxyethyl)isocyanoratetriacrylate,
tris(2-hydroxy)isocyanorate trimethacrylate, divinyl esters of
polycarboxylic acids, diallyl esters of polycarboxylic acids,
triallyl terephthalate, diallyl maleate, diallyl fumarate,
hexamethylenebismaleimide, trivinyl trimellitate, divinyl adipate,
diallyl succinate, and ethylene glycol divinyl ether,
cyclopentadiene diacrylate, triallylamine, tetraallylammonium
halides, divinylbenzene, divinyl ether,
N,N'-methylenebisacrylamide, N,N'-methylene-bismethacrylamide,
ethylene glycol dimethacrylate, and trimethylolpropane triacrylate.
Crosslinkers preferred among these are
N,N'-methylene-bisacrylamide, N,N'-methylenebismethacrylamide,
polyethylene glycol diacrylate, polyethylene glycol dimethacrylate,
and triallylamine.
[0036] The polymeric formations of the invention can be prepared
preferably by emulsion polymerization and preferably have an
average particle size of 10 to 5000 nm; an average particle size of
150 to 2000 nm is particularly preferred. Most preferable are
average particle sizes of 200 to 1000 nm.
[0037] The average particle size is determined, for example, by
counting a statistically significant amount of particles by means
of transmission electron micrographs.
[0038] For the preparation of the polymeric formations of the
invention it is possible to employ all of the initiators and
regulators that are customary for emulsion polymerization. Examples
of initiators are inorganic peroxides, organic peroxides or
H.sub.2O.sub.2, and also mixtures thereof with, if appropriate, one
or more reducing agents.
[0039] In accordance with the invention it is possible to employ
any ionic or nonionic emulsifier during or after the preparation of
the dispersion.
[0040] Whereas the water-filled polymeric microparticles are used
in accordance with the invention preferably in the form of an
aqueous dispersion, it is entirely possible within the context of
the present invention to add the water-filled microparticles
directly as a solid to the building material mixture. For that
purpose the microparticles are for example coagulated--by methods
known to the skilled worker--and isolated from the aqueous
dispersion by means of standard methods (e.g. filtration,
centrifuging, sedimentation and decanting). The material obtained
can be washed and is subsequently dried.
[0041] The polymeric formations are added to the building material
mixture in a preferred amount of 0.01% to 5% by volume, in
particular 0.1% to 0.5% by volume. The building material mixture,
in the form for example of concrete or mortar, may in this case
include the customary hydraulically setting binders, such as
cement, lime, gypsum or anhydrite, for example.
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