U.S. patent application number 10/517195 was filed with the patent office on 2006-05-11 for additive for hydraulically setting systems, the hydraulically setting mixtures and the use thereof.
Invention is credited to Erwin Buhler, Robert Koelliker, Hanspeter Waser.
Application Number | 20060100355 10/517195 |
Document ID | / |
Family ID | 29723132 |
Filed Date | 2006-05-11 |
United States Patent
Application |
20060100355 |
Kind Code |
A1 |
Waser; Hanspeter ; et
al. |
May 11, 2006 |
Additive for hydraulically setting systems, the hydraulically
setting mixtures and the use thereof
Abstract
The invention relates to an additive for hydraulically setting
systems based on modified polycarboxylates and water-soluble ethers
of high polymeric polysaccharides, optionally containing further
standard additives, characterized by a content of a) a
water-soluble ether of cellulose or a cellulose-like compound with
a viscosity of at least approximately 1,000 mPas, particularly at
least approximately 2,000 mPas, measured as a 2% aqueous solution
with a Brookfield viscosimeter at 20.degree. C. and 20 rpm and b) a
polycarboxylate, whose main chain is linked by means of ester,
ether, imide and/or amide groups with polyethylene oxide-containing
side chains. The invention also relates to hydraulic mixtures
having a content of the above additive and the use thereof. Using
the additive according to the invention in hydraulically setting
systems comparable and in part much better characteristics are
obtained compared with casein-containing formulations, such as a
theological flow behaviour comparable to casein, but with improved
water retention.
Inventors: |
Waser; Hanspeter;
(Hildisrieden, CH) ; Buhler; Erwin;
(Sempach-Stadt, CH) ; Koelliker; Robert;
(Oberkirch, CH) |
Correspondence
Address: |
NATIONAL STARCH AND CHEMICAL COMPANY
P.O. BOX 6500
BRIDGEWATER
NJ
08807-3300
US
|
Family ID: |
29723132 |
Appl. No.: |
10/517195 |
Filed: |
June 11, 2003 |
PCT Filed: |
June 11, 2003 |
PCT NO: |
PCT/EP03/06132 |
371 Date: |
August 29, 2005 |
Current U.S.
Class: |
524/556 ;
524/425 |
Current CPC
Class: |
C04B 28/02 20130101;
C04B 40/0039 20130101; C04B 40/0039 20130101; C04B 2103/46
20130101; C04B 40/0039 20130101; C04B 2103/0079 20130101; C04B
2111/1006 20130101; C04B 24/383 20130101; C04B 24/383 20130101;
C04B 28/02 20130101; C04B 24/2641 20130101; C04B 24/32 20130101;
C04B 24/383 20130101 |
Class at
Publication: |
524/556 ;
524/425 |
International
Class: |
C08L 31/00 20060101
C08L031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 12, 2002 |
CH |
102 26 088.5 |
Claims
1. Additive for hydraulically setting systems based on modified
polycarboxylates and water-soluble ethers of high polymeric
polysaccharides, optionally containing further standard additives,
characterized by a content of: a) a water-soluble ether of
cellulose or a cellulose-like compound with a viscosity of at least
approximately 1,000 mPas, particularly at least approximately 2,000
mPas, measured as a 2% aqueous solution with a Brookfield
viscosimeter at 20.degree. C. and 20 rpm, and b) a polycarboxylate,
whose main chain is linked via ester, ether, imide and/or amide
groups with polyethylene oxide-containing side chains.
2. Additive according to claim 1, characterized in that there are
approximately 0.01 to 2 parts by weight water-soluble ether a) for
approximately one part by weight modified polycarboxylate.
3. Additive according to claim 2, characterized in that there are
approximately 0.05 to 1.5 parts by weight, particularly
approximately 0.1 to 1.0 parts by weight water-soluble ether a) for
approximately 1 part by weight modified polycarboxylate.
4. Additive according to one of the claims 1 to 3, characterized in
that the water-soluble ether a) is in the form of a cellulose ether
and/or a guar ether.
5. Additive according to one of the claims 1 to 4, characterized in
that the water-soluble ether a) is in the form of a cellulose ether
with a degree of substitution of approximately 1.2 to 2.9,
particularly approximately 1.6 to 2.2.
6. Additive according to one of the claims 1 to 5, characterized in
that the water-soluble ether a) has etherification groups in the
form of alkoxy groups, particularly in the form of alkoxy groups
with 1 to 4 carbon atoms.
7. Additive according to claim 6, characterized in that the alkoxy
groups are methoxy, ethoxy and/or propoxy groups.
8. Additive according to at least one of the preceding claims,
characterized in that the water-soluble ether a) has a viscosity of
at least approximately 5,000 mPas, preferably at least
approximately 10,000 mPas and more particularly at least
approximately 20,000 mPas.
9. Additive according to at least one of the preceding claims,
characterized in that it contains further standard additives in the
form of agents for controlling the setting rate and strength
structure, defoamers, organic or inorganic binders, water
repellents, surfactants, pigments, fillers, quartz powder and/or
calcium carbonate.
10. Additive according to at least one of the preceding claims,
characterized in that it contains an organic binder in the form of
a dispersion powder.
11. Additive according to at least one of the preceding claims 1 to
9, characterized in that, based on approximately 1 part by weight
of a mixture of components a) and b), it contains at least
approximately 0.005 parts by weight additives, excluding
binders.
12. Additive according to one of the claims 9 or 10, characterized
in that there are at least approximately 1 part by weight organic
binder, particularly approximately 2 to 50 parts by weight thereof,
for 1 part by weight of the mixture of components a) and b).
13. Hydraulically setting mixture with a content of an additive
according to at least one of the preceding claims 1 to 12.
14. Hydraulically setting mixture with a content of an additive
according to at least one of the preceding claims 1 to 12, as well
as a content of organic binder in the form of a dispersion
powder.
15. Hydraulically setting mixture according to claim 13 or 14,
characterized in that the hydraulically setting component is based
on cement, optionally accompanied by the incorporation of lime
hydrate and/or gypsum.
16. Hydraulically setting mixture according to claim 15,
characterized in that the cement is in the form of Portland cement
and/or aluminous cement.
17. Hydraulically setting mixture according to one of the claims 13
to 16, characterized in that there are approximately 80 to 1,500
and in particular approximately 100 to 500 parts by weight of
hydraulically setting components for approximately 1 part by weight
of additive, based on the sum of components a) and b).
18. Hydraulically setting mixture according to at least one of the
claims 13 to 17, characterized in that it has a water retention
value exceeding that of a casein superplasticiser-containing,
hydraulically setting mixture with the same composition by more
than approximately 20%, particularly more than approximately
50%.
19. Use of the additive according to at least one of the preceding
claims 1 to 12 as a constituent of hydraulically setting systems,
particularly based on cement and/or aluminous cement.
20. Use according to claim 19, characterized in that the
hydraulically setting system additionally contains lime hydrate
and/or gypsum.
21. Use according to claim 19 or 20 in dry, grouting, injection and
repair mortars, flow control materials, plasters, sealing sludges,
fillers, surfacers, finished gypsum parts, concretes, such as
flooring plaster, continuously reinforced concrete, close texture
lightweight concrete, high strength concrete, normal concrete, in
situ concrete, exposed concrete, prestressed concrete, air-placed
concrete, reinforced concrete, self-sealing concrete (SCC),
transport concrete, preferably in self-levelling priming and
compensating materials, particularly self-levelling floor
compensating materials.
Description
[0001] The invention relates to additives for hydraulically setting
systems based on polycarboxylates and water soluble ethers of high
polymeric polysaccharides, the hydraulically setting mixtures with
a content of such additives and the use thereof.
[0002] It is known from the prior art to extensively use casein as
the superplasticiser for hydraulically setting formulations, i.e.
as an additive which reduces viscosity in order to obtain a
suitable flow behaviour. In formulations said casein component
leads to particularly good characteristics, which could not
hitherto be readily achieved with synthetic superplasticisers.
[0003] Casein is a natural product obtainable by acid treatment
from milk. However, it suffers from a number of known
disadvantages. Thus, casein is available in widely differing
qualities and in part at a widely differing price level on the
market, so that as a result of the non-constant composition
reproducible applications are not possible. In addition,
casein-containing formulations are forbidden in certain countries,
such as e.g. Scandinavia, because they split off during hydrolysis
of the amino groups present, which is not only toxicologically
objectionable, but can also lead to the discoloration and damage to
other materials.
[0004] Therefore there is a need for a material providing a similar
performance profile to casein, but without suffering from the above
disadvantages. So-called high performance concrete
superplasticisers are in part used for this purpose and in the same
way as casein-containing systems have good processability, easy
handling, but a different performance profile. These
superplasticisers are essentially subdivided into four groups,
namely sulphonated melamine-formaldehyde condensates, sulphonated
naphthalene-formaldehyde condensates, modified lignosulphonates and
a further group from sulphonates, polyacrylates, polystyrene
sulphonates, etc. For example, sulphonated melamine-formaldehyde
superplasticisers are used to a significant extent, but are losing
significance as a result of their tendency to release toxic
formaldehyde.
[0005] The hitherto known synthetic superplasticisers were mainly
developed for concrete, but as a result have in part also been used
in mortars. However, the excellent, liquefying action of these
known superplasticisers is only maintained for a short time, which
is particularly disadvantageous in the case of mechanical
processing if a considerable time elapses between production,
transportation and use. Moreover, with such synthetic
superplasticisers, it is not possible to regulate the honey-like
consistency like that provided by casein superplasticisers, so that
a completely different performance profile is exhibited.
[0006] The prior art has provided proposals attempting to optimize
this technology. Thus, JP 08217508 discloses a cement mixture
comprising a polyethylene oxide and protein-containing thickener, a
superplasticiser, a rapidly hardening agent and a setting
retarder.
[0007] U.S. Pat. No. 5,494,516 describes a process in which a
water-soluble polyalkylene oxide, a .beta.-naphthalene
sulphonate-formaldehyde condensate and a superplasticiser, selected
from lingosulphate, melamine sulphonate formaldehyde condensate,
carboxylates and styrene-maleic anhydride copolymers are brought
together. The soluble polyalkylene oxide can be replaced by up to
50% hydroxyalkyl cellulose. It is also possible to use other
superplasticisers. Application in conjunction with a spraying on of
a cement or mortar composition is very specific.
[0008] FR 9 400 170 relates to a casein substitute, composed of a
melamine formaldehyde condensate superplasticiser, cellulose, such
as hydroxyethyl cellulose and/or a heteropolysaccharide such as
xanthan gum.
[0009] According to EP 946 617 B1 carboxyl group-containing
polymers with polyalkylene oxide ether side chains are used and
phosphorus-containing compounds are added during
polymerization.
[0010] WO 86/00291 describes a cement mixture comprising
hydraulically setting cement, one or more flocculants, selected
from among sodium alginate, cellulose ether, poly-acrylates,
polyacrylamides, guar gum, gelatin, chitosan, dextrin and
dialdehyde starches, one or more water-reducing agents selected
from among sulphonated naphthalene/formaldehyde condensate,
sulphonated melamine/formaldehyde condensate, lignosulphonates,
modified lignosulphonates, salts of polyhydroxycarboxylic acids,
polyhydroxycarboxylic acids, glucosaccharides, copolymers of linear
or cyclic C4- to C6-olefins and unsaturated ethylene dicarboxylic
acids, an aggregate and water.
[0011] However, the prior art systems fail to provide satisfactory
results. When using the above-described, synthetic
superplasticisers the water is not retained in a suitable manner in
the formulation, e.g. in the mortar, i.e. it is too rapidly lost.
This behaviour, i.e. the water retention represents the strength of
retention of the water and a suitable water balance must exist. The
water losses are caused by an absorbent substrate or evaporation.
In order to give such a material a suitable water retention and to
prevent separation of the formulation, such materials consequently
contain further additives, such as corresponding thickeners. When
using excessive quantities of such additives, the viscosity becomes
too high and there is a reduction to an unacceptable level of the
flow characteristics of the material.
[0012] Accompanied by the further development of the
above-discussed prior art, the problem of the invention is to
provide a synthetic casein substitute in the form of an additive,
which compared with casein-containing formulations, offers
comparable or in certain cases even improved characteristics. In
their final applications in hydraulically setting systems, such
additives must also lead to improved use products. In particular,
the water retention of hydraulically setting systems is to be
improved.
[0013] According to the invention this problem is solved by an
additive for hydraulically setting systems based on modified
polycarboxylates and water-soluble ethers of high polymeric
polysaccharides, optionally containing further conventional
additives, characterized by a content of:
[0014] a) a water-soluble ether of cellulose or a cellulose-like
compound with a viscosity of at least approximately 1,000 mPas,
particularly at least approximately 2,000 mPas, measured as a 2%
aqueous solution with a Brookfield viscosimeter at 20.degree. C.
and 20 rpm and
[0015] b) a polycarboxylate, whose main chain is linked via ester,
ether, imide and/or amide groups to polyethylene oxide-containing
side chains.
[0016] A further object of the invention is a hydraulically setting
mixture with a content of the above additive and the use of the
additive as a constituent of hydraulically setting systems.
[0017] It has surprisingly been found that the invention can supply
an additive, which as a result of a very specific combination of
modified polycarboxylate superplasticiser and water-soluble ethers
of a high polymeric polysaccharide with high viscosity leads to a
considerable improvement to the rheological profile in
hydraulically setting systems. The results obtainable can be
equated with those of casein-containing formulations and are in
part even superior to the latter. Thus, much better water retention
values are obtained than with casein-containing systems with a
corresponding composition.
[0018] Two components are essential for the additive according to
the invention, i.e. the water-soluble ether a) and the modified
polycarboxylate b), which will now be described in detail.
[0019] As water-soluble ethers a) of polysaccharides, according to
the invention more particularly use is made of cellulose or
cellulose-like compounds with a viscosity of at least approximately
1,000 mPas, particularly at least approximately 2,000 mPas,
measured as a 2% aqueous solution using a Brookfield viscosimeter
at 20.degree. C. and 20 rpm. According to a particularly preferred
embodiment of the invention the water-soluble ether a) has a
viscosity of at least approximately 5,000 mPas, preferably at least
approximately 10,000 mPas, more particularly more than
approximately 15,000 mPas and very preferably above approximately
20,000 mPas and even more especially approximately 30,000 mPas.
[0020] Within the framework of the invention there is no particular
restriction with respect to the cellulose ethers, provided that
they have the indicated viscosity. In an exemplified enumeration
reference is made to: alkyl cellulose ethers, hydroxyalkyl
cellulose ethers, carboxyalkyl cellulose ethers,
hydroxyalkylpolyoxyalkyl cellulose ethers and the like, as well as
mixed ethers with at least two different substituents from the
group alkyl, hydroxyalkyl, carboxyalkyl and/or
hydroxyalkylpolyoxyalkyl with in each case C1- to C10-alkyl
groups.
[0021] In the present invention the cellulose-like compounds
comprise polysaccharides, which have a similar structure and/or
characteristics to cellulose, but which do not necessarily have a
similar structural form to cellulose, but can instead have a
completely different structure, but similar characteristics to
cellulose, e.g. with regards to the solution behaviour, chemical
reactivity, water retention, air void stabilization, etc.
[0022] Examples are chemically modified or unmodified compounds,
such as guar, dextran, chitin, chitosan, mannans, galactans,
xylans, starch, xanthan gum, Welan gum, Gellan gum, alginates,
arabinoxylan, glucan, gelatin, pectin, polyacrylates, polyethylene
glycols, polyurethane thickeners, lattice silicates, etc. Such
compounds together with their chemistry are known to the expert.
These include the compound types such as are described in EP 1 180
535 A1, i.e. thickeners based on compositions with vinyl alcohol
copolymers and cellulose ethers in which A) there are one or more
completely or partly saponified vinyl alcohol polymers with a
degree of hydrolysis of 75 to 100 mole % and a molecular weight
Mw>100,000, obtainable a) by the saponification of vinyl acetate
copolymers which, in addition to vinyl acetate units, also contain
comonomer units, which are derived from one or more comonomers from
the group comprising 1-alkyl vinyl ester with C1- to C5-alkyl
groups of C1- to C5-carboxylic acids, allyl esters, vinyl esters of
alpha-branched carboxylic acids with 5 to 12 C-atoms, acrylates and
methacrylates of C1- to C18-alcohols or obtainable b) by
acetalization of said saponified vinyl acetate copolymers or
saponified vinyl acetate homopolymers with aliphatic or aromatic,
optionally substituted aldehydes and B) one or more cellulose
ethers.
[0023] It is important according to the invention that the
viscosity of the water-soluble ether a) is at least approximately
1,000 mPas, because on dropping below this value there is a marked
deterioration to the rheological properties and in particular the
water retention drops to an unacceptable level.
[0024] In the present invention the viscosity is determined
according to Brookfield, measured in a 2% aqueous solution at
20.degree. C. and 20 rpm. The viscosity determination is described
in detail in the examples. It is surprising that the low viscosity
cellulose ethers normally used in the prior art, i.e. with a
Brookfield viscosity well below 1,000 mPas, do not give the desired
performance profiles. It would have been expected that as a result
of the high viscosity of the ethers according to the invention, the
formulations would thicken excessively and the materials would no
longer run, but this is not the case.
[0025] According to the invention the water-soluble ether a) is
preferably in the form of a cellulose ether and/or a guar ether.
The cellulose ether advantageously has a degree of substitution
(DS) in the range approximately 1.2 to 2.9, particularly
approximately 1.6 to 2.2, but can also extend up to 3, which means
a complete etherification of the cellulose. It is also preferable
for the water-soluble ether a) to have etherification groups in the
form of alkoxy groups, particularly in the form of alkoxy groups
with 1 to 4 carbon atoms, methoxy, ethoxy and/or propoxy groups
being mentioned in an exemplified manner. Particularly preferred
cellulose ethers according to the invention are methyl celluloses,
ethyl celluloses, propyl celluloses, hydroxymethyl celluloses,
hydroxyethyl cellulose, hydroxypropyl celluloses, methyl
hydroxymethyl celluloses, methyl hydroxyethyl celluloses, methyl
hydroxypropyl celluloses, ethyl hydroxymethyl celluloses, ethyl
hydroxyethyl celluloses, ethyl hydroxypropyl celluloses, propyl
hydroxymethyl celluloses, propyl hydroxyethyl celluloses and propyl
hydroxypropyl celluloses.
[0026] The second essential component according to the invention is
a modified polycarboxylate b), whose main chain is linked via
ester, ether, imide and/or amide groups to polyethylene
oxide-containing side chains. The main chain is essentially a
polymer with an anionic charge having several carboxylate groups.
This main chain contains numerous ethylene oxide side chains, which
can have different chain lengths and are connected to the main
chain by an ester, ether, imide or amide linkage. For illustration
purposes the attached FIGS. 1 to 4 show the individual linkages
between the main and side chains in the general structural
formulas. Thus, FIG. 1 shows an ester linkage of a polycarboxylate
skeleton with an ethylene oxide side chain. FIGS. 2, 3 and 4 show
linkages via an ether, imide and amide group respectively.
[0027] Within the scope of the present invention, there is no
particular restriction regarding the structure of the side chains,
provided that a polyethylene oxide is contained. However, great
importance is attached to the linking of the side and main chains
by means of an ester, ether, imide or amide group. This makes
available high performance superplasticisers in the form of
modified polycarboxylates, which have proved to be very efficient.
Thus, it is e.g. possible to prolong the flow action by a high side
chain density.
[0028] The total water requirement can be drastically reduced by
using such superplasticisers. In addition, the high performance
superplasticisers according to the invention, as opposed to
melamine formaldehyde superplasticisers, do not suffer from a
splitting off of formaldehyde. Thus, according to the invention use
is preferably not made of melamine-formaldehyde condensates and/or
naphthalene-formaldehyde condensates.
[0029] The polycarboxylates according to the invention can e.g. be
reaction products based on unsaturated monocarboxylic or
dicarboxylic acid or the derivatives thereof, such as maleic acid
or maleic anhydride and oxyalkylene glycol alkenyl ethers and
approximately 1 to 99 wt. % of the carboxylic acid or derivative
and approximately 99 to 1 wt. % oxyalkylene glycol alkenyl ether
are polymerized with the aid of a radical starter. A possible
skeleton for an oxyalkylene glycol alkenyl ether is shown in FIG.
5, where R1 represents H or an aliphatic hydrocarbon group with 1
to 10 C-atoms, which can be linear, branched, saturated or
unsaturated, R2 is H, an aliphatic hydrocarbon group with 1 to 20
C-atoms, a cycloaliphatic group with 5 to 8 C-atoms, an optionally
substituted aryl group with 6 to 14 C-atoms, in which x=0 to 3, y=2
to 4 and z=0 to 100. Examples are methyl polyethylene
glycol-monoallyl ether or methyl polyethylene glycol-monovinyl
ether.
[0030] Another particularly preferred variant of the invention
comprises reacting 1 to 99 wt. % of an (alkoxy)polyalkylene glycol
mono(meth)acrylate, (alkoxy)polyalkylene glycol mono(meth)allyl
ether or (alkoxy)polyalkylene glycol mono(meth)vinyl ether with 99
to 1 wt. % of an unsaturated monocarboxylic or dicarboxylic acid or
derivative thereof, such as (meth)acrylic acid. An example for a
skeleton of an (alkoxy)polyalkylene glycol mono(meth)acrylate is
shown in FIG. 6, in which R1 is H or an aliphatic hydrocarbon group
with 1 to 5 C-atoms, which is linear, branched, saturated or
unsaturated, R2O is an oxyalkylene group with 2 to 4 C-atoms, R3 is
hydrogen or an aliphatic hydrocarbon group with 1 to 22 C-atoms and
z=0 to 100.
[0031] The polycarboxylates according to the invention can also be
based on water-soluble or water-dispersible polymers, which contain
carboxyl groups and have polyalkylene oxide ether side chains, e.g.
obtainable by radical polymerization of ethylenically unsaturated
monomers, which contain carboxyl groups, and ethylenically
unsaturated monomers, which have side chains, in the presence of
phosphorus-containing compounds.
[0032] According to the invention, the polycarboxylate can also
have further functional groups, such as e.g. hydroxyl, ester,
ether, amide or aldehyde groups, to the extent that the effects
sought by the invention are not impaired.
[0033] In particularly preferred manner, the polyethylene side
chain-containing polycarboxylate according to the invention has
units, which are e.g. based on the following monomers:
(meth)acrylic acids, their monovalent and divalent metal salts,
ammonium salts and organic amino salts, esters of aliphatic
alcohols with 1 to 20 C-atoms with (meth)acrylic acid, unsaturated
dicarboxylic acids, such as maleic, fumaric, itaconic and
citraconic acids, their anhydrides, monoesters or diesters of said
acids with an aliphatic alcohol having 1 to 20 C-atoms or a glycol
with 2 to 4 C-atoms or a polyalkylene glycol containing 2 to 100 of
said glycols, saturated or unsaturated amides, such as
(meth)acrylamide and (meth)acrylalkylamide, vinyl or allyl ethers,
vinylesters, such as vinyl acetate and vinyl propionate, aromatic
vinyls, such as styrene, unsaturated sulphonic acids, such as vinyl
sulphonic acid, (meth)allyl sulphonic acid, sulphoethyl
(meth)acrylate, 2-(meth)acrylamide-2-methyl propane sulphonic acid
and styrene sulphonic acid and their salts.
[0034] Within the scope of the present invention obviously numerous
other embodiments are obvious to the expert and the above variants
can serve as an orientation.
[0035] It is appropriate according to the teaching of the invention
if for approximately one part by weight modified polycarboxylate b)
there are approximately 0.01 to 2 parts by weight, preferably
approximately 0.05 to 1.5 parts by weight, more particularly
approximately 0.08 to 1.2 parts by weight, and in particularly
preferred manner approximately 0.1 to 1.0 parts by weight
water-soluble ethers a).
[0036] Preferably, the additive according to the invention can
incorporate further conventional additives, such as e.g. agents for
controlling the setting rate, i.e. retardants, such as fruit acids,
or accelerators such as lithium carbonate, calcium fluoride or
calcium formate, agents for controlling the strength structure,
defoamers, inorganic or organic binders, such as copolymers or
terpolymers in the form of dispersion powders and fully and
partially hydrolysed polyvinyl alcohol with low, medium and high
molecular weight, polyvinyl pyrrolidone, polyethylene glycol (EO)
and ethylene oxid--propylene oxid (EO/PO) blockcopolymers, rheology
modifiers which might contain associative monomers, such as
polyurethane thickeners, starches, dextrines and polyacrylates, fly
ash, kaolin, water repellents, such as stearates or oleates, agents
for controlling the final strength, such as cellulose fibres,
surfactants, pigments such as iron or chromium oxides, fillers such
as sand, limestone, quartz powder and/or calcium carbonate. This
list does not claim completeness and further additives are in fact
known to the expert. Preferably for approximately one part by
weight of a mixture of components a) and b) there are at least
approximately 0.005 parts by weight, particularly at least
approximately 0.05 parts by weight of additives, excluding
binders.
[0037] In the present invention particularly preferred additives
are constituted by dispersion powders, which in the hydraulically
setting systems used according to the invention bring about an
improvement of certain characteristics. In particular, through the
use of dispersion powders it is possible to increase the adhesion
strength to the substrate and also the bending strength, the
deformability and abrasion resistance are improved and the crack
formation tendency is drastically reduced. With such an addition it
is possible to bring about adequate adhesion even to substrates
such as metal or wood. Thus, the use of dispersion powders ensures
a reliable quality of the characteristics profiles in the use
products.
[0038] Appropriately for approximately 1 part by weight of the
mixture of components a) and b), there is at least approximately 1
part by weight organic binder, such as dispersion powder and in
particular a quantity of approximately 2 to 50 parts by weight
thereof.
[0039] In the hydraulically setting mixtures in which the additive
according to the invention is used, the hydraulically setting
component can be based on cement, optionally accompanied by the
incorporation of lime hydrate and/or gypsum. Preferably the cement
is in the form of Portland cement and/or aluminous cement.
According to the invention it is particularly appropriate that for
approximately 1 part by weight additive, based on the sum of the
components a) and b), there are approximately 80 to 1,500 parts by
weight and in particular approximately 100 to 500 parts by weight
of hydraulically setting components.
[0040] The additive according to the invention, as a constituent of
hydraulically setting systems, is more particularly used in dry,
grouting, injection and repair mortars, flow control materials,
plasters, sealing sludges, fillers, surfacers, finished gypsum
parts, concretes, such as flooring plaster, continuously reinforced
concrete, close texture lightweight concrete, high strength
concrete, normal concrete, in situ concrete, air-placed concrete,
exposed concrete, prestressed concrete, self-sealing concrete
(SCC), ready-mixed concrete, preferably in self-levelling priming
and compensating materials, particularly self-levelling floor
compensating materials.
[0041] It has been found that as a result of the inventive
combination of the two components a) and b), synergistic effects
occur in the hydraulically setting systems or mixtures used.
[0042] Thus, the water-soluble ether a) is used in roughly
comparable qualities to the prior art. However, the content of high
performance superplasticiser according to the invention can be
significantly reduced. For example, compared with the
conventionally used quantity of a casein superplasticiser,
preferably only approximately 1/4 to 1/5 thereof is used in the
superplasticiser according to the invention. Also compared with
other known high performance superplasticisers according to the
prior art much lower contents are required in order to provide the
desired characteristics profiles, which leads to a significant cost
reduction.
[0043] Therefore the superplasticiser according to the invention
has a high liquefying action when very small quantities are used.
The advantage of a good liquefaction is in particular that less
water is needed and a better flowing together of the formulations
is obtained.
[0044] Although a much lower superplasticiser quantity is used in
the additive according to the invention, the additive-containing,
hydraulically setting mixtures according to the invention
surprisingly have comparable and in part much better
characteristics to casein-containing formulations. Thus, a
Theological flow behaviour comparable to casein formulations is
obtained.
[0045] Conventionally the prior art only uses low viscosity
cellulose ethers for hydraulically setting formulations, such as in
particular floor levelling materials, i.e. having a Brookfield
viscosity well below 1,000 mPas. It is therefore extremely
surprising that high viscosity cellulose ethers such as are used in
the invention are suitable for such applications. As a result of
the high viscosity it would be expected that there would be an
excessive thickening of the formulation, which would greatly impair
the running of the materials. However, this has not been observed
with the inventive combination of thickener and superplasticiser
and instead excellent flow characteristics occur. Thus, the
hydraulically setting mixtures according to the invention have a
honey-like flow behaviour, such as in particular only occurs with
casein-containing materials and which cannot be achieved with the
known synthetic superplasticisers.
[0046] Moreover, with the mixtures according to the invention much
higher water retention values are obtained. The water retention is
controlled via the water-soluble ether a). As has already been
explained, a rise in the ether quantity leads to a marked
thickening of the material, so that flowability is worse. It is
therefore completely unexpected that in spite of the use of equal
amounts of water-soluble ether a) compared with the prior art and a
much smaller quantity of superplasticiser b), an unexpected rise in
the water retention is obtained as a result of the cooperation of
the two components.
[0047] In the hydraulically setting mixtures containing the
additive according to the invention water retention values are
obtained, which are better than the water retention value of a
casein superplasticiser-containing hydraulically setting mixture
with the same composition by more than approximately 20%,
preferably more than approximately 50%, especially more than
approximately 80% and in particularly preferred manner more than
approximately 100%. A casein superplasticiser-containing
hydraulically setting mixture with the same composition in this
context means that all the constituents are identical and present
in the same quantity, except for the casein superplasticiser, which
is added in a quantity such that a comparable consistency is
obtained.
[0048] The invention also leads to a number of other advantages.
The high performance superplasticiser according to the invention
leads to significant water economies. Generally much more water is
required for mixing the formulation than for the subsequent setting
or hardening process. The excess, evaporating water leads to the
formation of cavities in the hardened material and therefore to a
significantly inferior mechanical strength and stability. As
opposed to this, the high performance superplasticiser according to
the invention can significantly reduce the excess water percentage
with a predetermined processing consistency. The particularly good
processability of the materials according to the invention is e.g.
revealed in good flow characteristics, i.e. better running and
flowing together without sediment formation.
[0049] The pumpability and stability of the hydraulically setting
systems is improved by even small quantities of water-soluble ether
a), so that the latter gives the systems an improved
processability, in addition to a good thickening action. The
prevention of bleeding prevents sedimentation and contributes to
homogeneity in hydraulically setting systems.
[0050] When used the mixtures according to the invention satisfy
the highest demands regarding processability and provide the
desired strength and durability, high initial and final strengths,
improved tightness, reduced separation and bleeding. The mixtures
harden rapidly. The minimum shrinkage tendency without cracking,
such as exists according to the invention, is very important,
particularly for floor materials applied in relatively thin layers.
It is also possible by additives in the form of dispersion powders
to improve characteristics such as the adhesion strength,
scratching and abrasion resistance and bending strength. The
materials also have a so-called self-healing effect, i.e. two
separately applied layers give a uniform surface. The surface of
the end products has the desired high quality.
[0051] The compatibility of the two components exists in all
cements. However, in individual cases advantages arise when using
special compounds, optionally accompanied by the incorporation of
additives, which enable desired characteristics to be set in
planned manner. The invention consequently leads to a balanced
system and flexibility is brought about by adding additives.
[0052] The invention is described in greater detail hereinafter
relative to examples not intended to restrict the teaching of the
invention. Further embodiments are obvious to the expert within the
framework of the disclosure of the present invention.
EXAMPLES
[0053] The examples use the following compounds:
[0054] Culminal.COPYRGT. MHEC 250000PFF*): unmodified**) methyl
hydroxyethyl cellulose with a viscosity of 25,000 mPas, determined
as 2% aqueous solution with Brookfield RV at 20.degree. C. and 20
rpm;
[0055] Culminal.COPYRGT. C4045*): modified***) methyl cellulose
with a viscosity of 38,000 to 51,000 mPas, determined as 2% aqueous
solution with Brookfield RV at 20.degree. C. and 20 rpm;
[0056] Tylose.COPYRGT. H4000P*): unmodified**) methyl hydroxyethyl
cellulose with a viscosity of 3,800 to 5,300 mPas, determined as
1.9% (dry substance) aqueous solution with Brookfield RV at
20.degree. C. and 20 rpm;
[0057] Tylose.COPYRGT. MH60001P4*): modified***) methyl
hydroxyethyl cellulose with a viscosity of 27,000 to 34,000 mPas,
determined as 1.9% (dry substance) aqueous solution with Brookfield
RV at 20.degree. C. and 20 rpm;
[0058] Natrosol 250GXR: low viscosity hydroxyethyl cellulose with a
viscosity of 250 to 450 mPas, determined according to Brookfield
LVF at 25.degree. C. in 2% solution;
[0059] Melment.COPYRGT. F10: melamine formaldehyde
superplasticiser;
[0060] Melflux.COPYRGT. 1641F: polyether carboxylate
superplasticiser according to the invention;
[0061] Elotex Flow 8200: polyether carboxylate superplasticiser
according to the invention;
[0062] Trisodium citrate: retardant;
[0063] Tartaric acid: retardant;
[0064] Quartz sand: filler;
[0065] Omyacarb 10BG: filler;
[0066] Quartz powder K4: filler;
[0067] Agitan P800: defoamer;
[0068] Lithium carbonate: strength-increasing additive
[0069] Elotex FL2211: Dispersion powder (organic binder based on an
ethylene-vinyl acetate copolymer). *) cellulose ether according to
the invention **) unmodified: no additives ***) modified: mixed
with additives.
[0070] The characteristics of the compositions are determined with
the aid of the following test methods:
[0071] a) Determination of the extent of spreading of a levelling
material
[0072] 100 g of dry mortar are mixed with water. A metal ring
(diameter 53 mm) is placed on a horizontal glass plate and
following a maturing time of 3 minutes the mortar is emptied into
the ring. 1 minute after removing the ring the diameter of the
mortar mass which has flowed is measured.
[0073] b) Determination of the scratch hardness
[0074] With the mortar one day old, it is scratched with a sharp
object and the surface hardness evaluated.
[0075] c) Determination of the water retention
[0076] The mixed mortar is emptied with a specific coating
thickness onto a highly absorbent tile. The time up to which the
watery gloss on the surface has disappeared is measured.
[0077] d) Viscosity determination
[0078] 30 g of hot water (approx. 80 to 90.degree. C.) are placed
in a 200 ml beaker and stirred with a propeller stirrer. 2.0 g of
cellulose ether are slowly added. Stirring continues for a certain
time until the cellulose ether has dissolved. 70 g of cold water
(approx. 5 to 10.degree. C.) are slowly added, accompanied by
stirring. Further stirring takes place and the solution cools to 20
or 25.degree. C., so that the Brookfield viscosity can be measured
at 20 rpm. It is ensured that no air is stirred in throughout the
stirring process.
[0079] The formulations given in the following table were prepared
and tested. TABLE-US-00001 Formulation Comp. Ex. 1 Comp. Ex. 2
Comp. Ex. 3 Comp. Ex. 4 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Cement CEM I
52.5 26.00 26.00 26.00 26.00 26.00 26.00 26.00 26.00 26.00
Aluminous cement 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00
10.00 Lime hydrate 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00
Hard moulding plaster No. 1 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00
4.00 Quartz sand 0.1-0.3 mm 38.90 39.25 43.44 43.85 39.00 39.00
43.84 43.64 43.85 Omyacarb 10BG 5.00 5.00 10.00 10.00 5.00 5.00
10.00 10.00 10.00 Quartz powder K4 9.80 9.80 9.80 9.80 Casein 110
mesh 0.40 Elotex Flow 8200 0.10 0.15 0.15 0.10 0.15 Trisodium
citrate 0.25 Tartaric acid 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25
Agitan P800 0.10 0.05 0.05 0.05 0.05 0.05 0.05 Agitan P843 0.05
0.05 Elotex FL2211 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
Natrosol 250GXR 0.05 0.05 Culminal .RTM.MHEC 25000PFF 0.05 Culmlnal
.RTM.C4045 0.05 Tylose .RTM.H4000P 0.06 0.06 0.06 Tylose
.RTM.MH60001P4 0.05 0.05 Lithium carbonate 0.20 0.20 0.20 Melment
.RTM.F10 0.50 Sodium Lignosulphonate 0.70 Melflux .RTM.1641F 0.30
Water requirement 22% 22% 23% 21% 22% 22% 22% 22% 21% Spreading of
composition 179 183 165 135 171 175 172 177 171 dia. mm after 2 min
Water retention on ceramic 4' 2'45'' 3' 3'10'' 6'30'' 6' 5' 5'
6'45'' tile, time Scratch hardness after 1 day, OK OK OK OK OK OK
OK OK OK 23.degree. C./50% rel. hum, but many evaluation cracks
[0080] Comparison example 1 is a known, casein-containing
formulation with standard characteristics.
[0081] Comparison example 2 contains a synthetic carboxylate
superplasticiser and a cellulose ether with a standard viscosity
profile, such as is conventionally used in self-levelling floor
compensating materials. The results reveal a comparable flow
(extent of spread), but a much lower water retention compared with
the cellulose ether, which is unacceptable. This comparison example
shows that the materials float off, i.e. are too watery. The water
retention is much lower than in the casein comparison product, so
that these compositions provide completely inadequate
characteristics.
[0082] Comparison example 3 uses Melment.COPYRGT. F10, a standard
melamine formaldehyde condensate superplasticiser, together with a
cellulose ether having a viscosity in the range according to the
invention. As a result of the low efficiency of Melmen.COPYRGT. F10
a five times higher quantity has to be used than in the case of a
carboxylate superplasticiser according to the invention. In spite
of this the amount of spread is low and the water retention
completely inadequate. In addition, on hardening the material
suffers from numerous cracks. Thus, in comparison example 3 use is
made of a melamine formaldehyde superplasticiser with a high
viscosity cellulose ether, which roughly corresponds to the
teaching of FR 2 714 912. This composition flows very poorly and
also has a relatively low level of spread, so that its
characteristics profile is completely inadequate.
[0083] Comparison example 4 has a formulation with completely
inadequate characteristics using sodium lignosulphonate as the
superplasticiser and Tylose.COPYRGT. MH60001P4 as the
superplasticiser. This roughly corresponds to the teaching of EP
188 471 B1. As is apparent from the comparison example, the amount
of spread is very poor and the water retention with 3'10'' is
completely inadequate.
[0084] In the case of examples 1 to 5 according to the invention
comparable parameters are obtained to casein with 0.1 or 0.15% of
superplasticiser according to the invention. The amount of spread
is lower, but is still good. The water retention is significantly
improved, namely 5 or 6 minutes compared with 4 minutes for casein.
Similar results are obtained with a further commercial product (SKW
Melflux.COPYRGT. 1641F, polycarboxylate superplasticiser), but
higher quantities are required.
[0085] In examples 1 to 5 according to the invention, the best
results are obtained with 0.15% superplasticiser according to the
invention and 0.05% cellulose ether with a viscosity of 25,000 mPas
(example 1), 4,000 mPas (example 2) and 27,000 to 34,000 mPas
(example 5), giving an excellent water retention of 6.5, 6 and 6.75
minutes respectively.
* * * * *