U.S. patent application number 12/066755 was filed with the patent office on 2009-09-10 for powder redispersible in water, process for production thereof and use thereof.
This patent application is currently assigned to National Starch and Chemical Investment Corporation. Invention is credited to Thomas Aberle, Adrian Keller.
Application Number | 20090223416 12/066755 |
Document ID | / |
Family ID | 35995283 |
Filed Date | 2009-09-10 |
United States Patent
Application |
20090223416 |
Kind Code |
A1 |
Aberle; Thomas ; et
al. |
September 10, 2009 |
POWDER REDISPERSIBLE IN WATER, PROCESS FOR PRODUCTION THEREOF AND
USE THEREOF
Abstract
The present invention relates to an additive for hydraulically
binding systems for reduction of blooms in hydraulically bound
systems, which is preferably present as a powder redispersible in
water and is suitable in particular as additive for addition in dry
mortars. The powder redispersible in water consists of at least one
organic component and at least one water-soluble organic polymeric
protective colloid and also if appropriate further additives, with
the organic component containing at least one compound having a
cyclic group which is completely or partially saturated and having
a melting point of about -20 to 250.degree. C. and also a molecular
weight of about 100 to 10 000, and forming a stable dispersion in
water with the water-soluble organic polymeric protective colloid,
with the weight ratio of the organic component to the water-soluble
organic polymeric protective colloid being about 95:5 to 5:95. The
invention also relates to a process in which the drying step is
omitted. The additive of the invention can be used in hydraulically
binding masses, in particular in concrete, gypsum and/or lime
and/or cement plasters, repair mortars and/or full heat protection
mortars, jointing adhesives and/or tile adhesives, levelling
compounds and/or fillers, non-shrink grouting and/or as additive
for concrete coatings and for adhesives.
Inventors: |
Aberle; Thomas; (Nottwil,
CH) ; Keller; Adrian; (Rupperswil, CH) |
Correspondence
Address: |
KENYON & KENYON LLP
ONE BROADWAY
NEW YORK
NY
10004
US
|
Assignee: |
National Starch and Chemical
Investment Corporation
|
Family ID: |
35995283 |
Appl. No.: |
12/066755 |
Filed: |
September 21, 2006 |
PCT Filed: |
September 21, 2006 |
PCT NO: |
PCT/EP06/09191 |
371 Date: |
August 22, 2008 |
Current U.S.
Class: |
106/822 ;
524/77 |
Current CPC
Class: |
C04B 2111/00517
20130101; C04B 2111/21 20130101; C04B 2111/00672 20130101; C04B
2103/0057 20130101; C04B 24/2623 20130101; C04B 40/0042 20130101;
C04B 24/34 20130101; C04B 40/0039 20130101; C04B 40/0039 20130101;
C04B 24/2623 20130101; C04B 24/34 20130101; C04B 24/42 20130101;
C04B 40/0042 20130101; C04B 24/2652 20130101; C04B 24/34 20130101;
C04B 24/42 20130101; C04B 40/0042 20130101; C04B 24/10 20130101;
C04B 24/34 20130101; C04B 40/0042 20130101; C04B 24/08 20130101;
C04B 24/14 20130101; C04B 24/26 20130101; C04B 24/34 20130101; C04B
24/42 20130101; C04B 2103/65 20130101; C04B 40/0042 20130101; C04B
14/04 20130101; C04B 14/06 20130101; C04B 14/26 20130101; C04B
24/26 20130101; C04B 24/2623 20130101; C04B 24/34 20130101; C04B
24/383 20130101; C04B 28/02 20130101; C04B 2103/10 20130101; C04B
2103/20 20130101; C04B 2103/30 20130101; C04B 2103/44 20130101 |
Class at
Publication: |
106/822 ;
524/77 |
International
Class: |
C04B 24/34 20060101
C04B024/34 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2005 |
EP |
05021009.5 |
Claims
1. Powder redispersible in water comprising: an organic component
having at least one compound with a cyclic group, the compound
being completely or partially saturated and having a melting point
of approximately -20 to 250.degree. C. and a molecular weight of
about 100 to 10,000, the organic component further having a
terpeneoid, a resin acid, colophony, terpene resin, terpene-phenol
resin and/or their derivatives, and a water-soluble organic
polymeric protective colloid, wherein the organic component and the
protective colloid form a stable dispersion in water, the
water-soluble organic polymeric protective colloid having a content
of monocarboxylic acid and dicarboxylic acid as well as their
anhydrides of less than 50 mole %, and not consisting of aromatic
sulfonic acid, condensates, and wherein the weight ratio of the
organic component to the water-soluble organic polymeric protective
colloid is 95:5 to 5:95, and wherein the powder reduces
efflorescence in hydraulically set systems.
2. Powder according to claim 1 wherein the cyclic group of the
organic component is a monocyclic, dicyclic, tricyclic, tetracyclic
and/or pentacyclic group.
3. Powder according to claim 1 wherein the organic component is a
natural product.
4. Powder according to claim 1 wherein the organic component
further comprises at least one compound with at least one carboxyl
group, carbonyl group, aldehyde group and/or alcohol group.
5. Powder according to claim 1 wherein the organic component
further comprises abietic acid, sylvic acid, neoabietic acid,
levopinaric acid, pimaric acid, isopimaric acid and/or palustric
acid and/or their derivatives.
6. Powder according to claim 1 wherein the organic component is not
or only slightly soluble in acidic to neutral water.
7. Powder according to claim 1 wherein the organic component is
partially or completely soluble in dilute caustic soda
solution.
8. Powder according to claim 1 wherein the water-soluble organic
polymeric protective colloid is a synthetic protective colloid in
the form of a modified and/or unmodified polyvinyl alcohol with a
degree of hydrolysis of 70 to 100 mole % and a Hoppler viscosity,
as 4% aqueous solution, of 1 to 50 mPas, measured at 20.degree. C.
according to DIN 53015, and/or polyvinyl pyrrolidone.
9. Powder according to claim 1 wherein the water-soluble organic
polymeric protective colloid is a natural and/or synthetically
produced biopolymer that can be synthetically modified.
10. Process for the production of powders redispersible in water
according to claim 1 comprising: dispersing the organic component
in water, stabilizing the dispersion with the water-soluble organic
polymeric protective colloid, and drying the aqueous dispersion
thereby forming the redispersible powders.
11. Process according to claim 10 wherein the solids content of the
stabilized dispersion is approximately 10 to 75% by weight and the
average particle size of the dispersed particles to approximately
0.05 to 50 .mu.m.
12. Process according to claim 10 wherein further liquid and/or
water-soluble additives are added before, during or after formation
of the dispersion, and further additives in powder form are added
during or after drying.
13. Process according to claim 10 further comprising mixing the
redispersible powder with film-forming dispersion powders
redispersible in water, redispersible hydrophobing agents in powder
form based on silanes, siloxanes, silicones, fatty acids and/or
fatty acid esters and/or polysaccharide ethers.
14. Process according to claim 10 wherein the aqueous dispersion is
dried jointly with at least one other dispersion based on
film-forming polymers and/or silanes, silane esters, siloxanes,
silicones, fatty acids and/or fatty acid esters, wherein the
dispersions are mixed with each other before drying or sprayed
separately and subsequently dried jointly.
15. Process according to claim 14 wherein the aqueous dispersion is
stabilised by emulsifiers and the at least one other dispersion
comprises an excess of water-soluble organic polymeric protective
colloid in water, the water-soluble organic polymeric protective
colloid having a content of monocarboxylic and dicarboxylic acids
and their anhydrides of less than 50 mole % and not consisting of
aromatic sulfonic acid condensates.
16. Powder redispersible in water obtained according to the process
according to claim 15.
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
Description
[0001] The present invention relates to a powder redispersible in
water for the reduction of efflorescence in hydraulically set
systems based on at least one organic component and at least one
water-soluble organic polymeric protective colloid, to a process
for its production including dispersion with subsequent drying, it
being possible to omit the drying step, and to its advantageous use
in particular as additive for hydraulically setting systems for the
reduction of efflorescence in hydraulically set systems.
[0002] Efflorescence is known to occur in particular in
cementitious systems such as concrete, rendering and mortars. The
expert means by it whitish deposits on the surface which are formed
above all by leached-out calcium hydroxide which is reacted further
by carbon dioxide from the air to form calcium carbonate. In this
case, further salt deposits may also be present. Although such
efflorescence usually have no major influence on the physical
values of the substrate, they are regarded a major nuisance
particularly in the case of coloured or grey surfaces.
[0003] Lacking alternatives, the formulation developer frequently
tries to prevent efflorescence by means of hydrophobic additives.
In this case, the idea plays a part that, if no water is able to
penetrate into the mortar layer, rendering layer or concrete layer,
no calcium hydroxide can be washed out. However, this is an
erroneous conclusion to be drawn: on the one hand, the freshly
applied material still contains a lot of water which, together with
dissolved salts, migrates to the surface. If the water evaporates,
the salt residues remain as undesired residues. In addition, water
can also diffuse from the other side through the hydraulically set
material and thus have the same effect. On the other hand, it is
practically impossible to obtain absolute hydrophobicity. Even if
the surface exhibits an excellent water repellency, it is
sufficient, if only a little water penetrates inside, to leave a
white residue behind after drying of the water droplet. Thus, many
highly hydrophobic materials exhibit a stronger efflorescence
effect than others. This shows also clearly that hydrophobicity and
efflorescence are based on quite different mechanisms and are not
comparable with each other.
[0004] Thus, DE 103 23 205 A1, for example, describes a
hydrophobing, water-redispersible additive based on fatty acids and
their derivatives which contain water-soluble protective colloids
and one or several compounds from the group of fatty acids and
fatty acid derivatives which, under alkaline conditions, liberate
fatty acid or the corresponding fatty acid anion, where required in
combination with one or several organosilicon compounds. By using
this additive in mortars, the water absorption is substantially
reduced but not prevented. There is no mention of a possible
reduction of efflorescence. Moreover, highly volatile organic
components (VOC) are usually formed by the alkaline hydrolysis of
the fatty acid derivatives.
[0005] U.S. Pat. No. 3,423,219 describes a process for the
production of Portland cement. During this process, an aqueous
dispersion of a mixture of tall oil resin and high-boiling
fractions of tall oil is preferably admixed to the Portland cement
as painting aid. The process for the production of such dispersions
comprises, among other things, an alkaline treatment and is
consequently complicated and expensive. The use of such systems for
reducing efflorescence is not mentioned. Moreover, no powders that
are soluble or redispersible in water are described, which makes
the use of dry mortars, in particular, impossible.
[0006] GB 1,088,484 A describes a process for inhibiting
efflorescence in concrete based on Portland cement. In this case,
an aqueous dispersion of a mixture of tall oil resin and
high-boiling fractions of tall oil, partially also mixed with
asphalt, is preferably admixed to the concrete or subsequently
applied onto the surface. The process for the production of such
dispersions comprises, among other things, an alkaline treatment
and is consequently highly complicated and thus expensive, the dark
to black colour of the mixture restricting its use considerably. To
stabilise the dispersions, 0.1 to 15% by weight of proteins or
polysaccharides are used. In addition, no powders soluble or
redispersible in water are described, which makes the use in
particular in dry mortars impossible.
[0007] In DE 33 21 027 A1, a process is described by means of which
a reduction of the efflorescence and a reduction of the water
absorption, among other things, apparently occurs. During this
process, terpene polymers, in particular of liquid low-molecular
terpenes, are added as such or in mixture with other terpene
hydrocarbons, which are added to the cement-containing building
materials in a quantity of 0.1-10% by weight. The addition of the
terpene-based compounds takes place in the emulsified form or by
spraying liquid or dissolved terpenes, precluding the use in dry
mortars, among other things. Moreover, no details are provided
regarding the type of terpenes used or the emulsifiers by way of
which the terpene compounds are emulsified.
[0008] JP 1 252 652 A describes an aqueous dispersion with an
excellent stability for paper applications, for example. In this
process, a hydrophobic substance with a low molecular weight is
dispersed by means of a modified polyvinyl alcohol which contains a
special cationic group, it being possible for the hydrophobic
substance with a low molecular weight to be a resin. The aqueous
dispersion described can be produced only with major effort since
the polyvinyl alcohol with the cationic group must be produced
first separately by means of the radical polymerisation of vinyl
acetate and dimethyl aminoethyl vinyl ether, for example, with
subsequent saponification of the copolymer. In addition, this
dispersion is not obtainable in powder form and has a quite
different field of application.
[0009] In EP 874 471 B1, a redispersible dispersion powder
composition is described, which consists of a water-insoluble base
polymer from the group of homopolymers and copolymers and a
water-soluble atomisation protective colloid which contains also up
to 100% by weight, based on the base polymer, of tackifying
substances. The water-soluble atomising protective colloid is a
non-neutralised or a partially neutralised special polymer based on
homopolymers or copolymers of olefinically unsaturated
monocarboxylic acids or dicarboxylic acids or their anhydrides, the
acid content of the polymer amounting to 50 mole % or more. The pH
of the aqueous redispersion is below 4.5. These systems can be used
as adhesive composition but should also be used in
cement-containing trowelling compounds, or in structural adhesives.
However, these specialty polymers rapidly form complex compounds
with calcium ions in hydraulically setting systems, and other ions
which has a highly negative effect on hydration (substantial
retardation) and on the mortar rheology (partial stiffening). For
this reason, they have little suitability in particular for use in
cementitious systems. A possible reduction of efflorescence is not
mentioned.
[0010] EP 874 877 B1 describes a tackifyer powder composition
redispersible in water containing one or several tackifying
substances and 2 to 50% by weight of at least one compound from the
group of water-soluble, low molecular homopolymers or copolymers of
olefinically unsaturated monocarboxylic acids or dicarboxylic acids
or their anhydrides, which contain, as copolymers, 2 to 50 mole %
of further free radical polymerisable monomers and phenol sulphonic
acid condensates, melamine sulphonic acid condensates and
naphthalene sulphonic acid condensates with a water solubility of
at least 10 g in 100 g of water and a molecular weight of maximum
250,000 g/mole. The tackifying substances are used as
emulsifier-stabilised dispersions and are not stabilised with these
polymers. In addition, they are used as adhesives and not in
cementitious systems, in particular not for the reduction of
efflorescence.
[0011] EP 799 876 A2 describes an adhesive composition in powder
form which contains at least one polymer based on at least one
dispersion, at least one tackifying resin and, where required, one
or several protective colloids as well as anticaking agents. This
adhesive composition is suitable for adhesive-bonding porous and
semi-porous substances, in particular as flooring adhesive. Use in
hydraulically setting systems is not mentioned, in particular not
the use for reducing efflorescence. Moreover, it is essential for a
polymer based on at least one dispersion to be contained therein,
which restricts the possibilities of formulation exceedingly.
[0012] It has been the object of the invention to provide an
additive which prevents or at least greatly reduces the
efflorescence of hydraulically set systems, in particular those
based on cement, such as e.g. in mortars, and in the case of
concrete. In addition, the additive should be present in powder
form in particular for the formulation of dry mortars in order to
circumvent the known disadvantages of liquid raw materials such as
e.g. lack of resistance to freezing/thawing or limited storage
stability, without the addition of toxic biocides and to allow
simple metering in the case of dry mortar formulations. However, it
should also be possible to meter in the additive in the liquid form
for selected applications such as e.g. the manufacture of concrete.
In addition, it is essential that this additive be suitable for
simply being stirred into the mortar matrix mixed with water
without special mixing processes having to be taken into account.
In this case, it is also very important that the additive can be
thoroughly wetted in the mortar mixture, redispersed and easily
homogeneously distributed in the matrix. In addition, it is
important that no disadvantageous or other mortar properties are
obtained by way of the additive, i.e. it should be possible for the
additive to be introduced into existing mortar formulations without
their properties, such as e.g. the mortar rheology, being modified,
except for the desired strong reduction of the efflorescence effect
and, where applicable, an improvement in the hydrophobicity and/or
adhesive capacity of the mortar. It should additionally be possible
to meter the additive independently of other mortar raw materials
providing the formulator with a very high level of flexibility. In
addition, it is important that the raw material costs and
production costs of the dry mortar are not or only slightly altered
by the additive. When producing the additive, it should, moreover,
be possible to simply vary the primary particle size without
problem in order to be able to adjust the final characteristics in
a targeted manner. Moreover, it is advantageous if at least a major
part of the additive can be obtained from renewable resources.
Also, the additive should have no or only a very low hazards
classification.
[0013] Surprisingly enough, it was possible to achieve the complex
object by way of a powder redispersible in water for reducing
efflorescence in hydraulically set systems based on at least one
organic component and at least one water-soluble organic polymeric
protective colloid and, where required, further additives,
whereas
a) the organic component containing at least one compound with a
cyclic group, the compound being completely or partially saturated
and having a melting point of approximately -20 to 250.degree. C.
and a molecular weight of about 100 to 10,000 and the organic
component containing a terpenoid, a resin acid, colophony, terpene
resin, terpene-phenol resin and/or their derivatives, and b)
forming, with the water-soluble organic polymeric protective
colloid, a stable dispersion in water, the water-soluble organic
polymeric protective colloid having a content of monocarboxylic
acid and dicarboxylic acid as well as their anhydrides of less than
50 mole % and not consisting of aromatic sulphonic acid condensates
and c) the weight ratio of the organic component to the
water-soluble organic polymeric protective colloid being 95:5 to
5:95.
[0014] The organic component with a completely or partially
saturated cyclic group can be a synthetically produced product or a
natural product. Suitable natural products are in particular resins
such as gum rosin, wood rosin, tall oil resin and/or polyterpene
resins, it being possible for these to be present in the modified
and/or unmodified form, it being possible for the modification to
be of natural or synthetic origin. Preferred terpeneoids are
monoterpenes, sesquiterpenes, diterpenes, sesterterpenes,
triterpenes, tetraterpenes and polyterpenes. Terpene resins are
typically obtained by the polymerisation of terpenes, diterpenes
and/or limonenes and terpene-phenol resins can be produced by the
acid-catalysed addition of phenols to terpenes and/or colophony,
but may also be based on other substances.
[0015] It is important for the organic component to contain at
least one cyclic group. Monocyclic, dicyclic, tricyclic,
tetracyclic and/or pentacyclic groups are preferred. A special
embodiment consists of organic components containing at least one
cyclic group with a C.sub.5-ring and/or C.sub.6-ring. In addition,
the cyclic group can be completely or partially saturated. A
special embodiment contains two or more C.dbd.C double bonds, at
least two being conjugated with each other.
[0016] The organic component may additionally contain at least one
compound with one or several functional groups such as e.g. amine
groups, amide groups, amidine groups, imine groups, anhydride
groups, ester groups, sulphate groups, sulphonate groups and/or
thiol groups. Compounds with carboxyl groups, carbonyl groups,
aldehyde groups and/or alcohol groups are particularly preferred,
whereas resin acids and their derivatives are particularly
preferred.
[0017] The following are, for example, suitable organic components:
monoterpenes such as camphor, camphoric acid, isonitrosocamphor,
camphor quinone, menthol, limonene, pinene, camphor carboxylic acid
and/or alkyl hydroxyl methylene camphor as well as their
derivatives and polymers produced therewith such as polyterpene
resins, diterpenes such as e.g. neoabietic acid, levopinaric acid,
pimaric acid, isopimaric acid, abietic acid, dehydroabietic acid,
dihydroabietic acid, sylvic acid, palustric acid, colophony,
retinal, tretinoine, agelasine E, agelasidine B, oxocativic acid,
pinifolic acid, labdene dioic acid, dihydroxy-halima-diene dioic
acid, epoxyclerodatrieneoic acid, isopimaradiene acid, isopimaric
acid, isopimaradiene diol, isopimaratriene triol, junceic acid,
podocarpinic acid, podocarpinol, roseine III, hydroxyoxorosenolide,
cassaic acid, cassaidine, cassaine, cassamine, auricularic acid,
cleistanthadienoic acid, isocopalene dial, abietadienoic acid,
abietic acid, dihydroxy-abtietatrienoic acid, lanugone A,
carnosolic acid, abeo-abietane, coleon P, cycloabietane, beyerene
triol, beyerol, hydroxybeyerenic acid, dihydroxykaurenic acid,
dihydroxykaurenolide, kahweol, methyl butanoyloxy-villanovane diol,
dihydroxyatisenolide, dihydroxy-atisanone, atisene diol,
gibberelline A.sub.18, gibberelline A.sub.1, gibberelline A.sub.3,
giberellic acid, grayanotoxene pentol, leucothol,
epoxygrayanotoxane pentol, rhodojaponin III, leucothol C, xeniolite
A, xeniaacetal and/or dihydroxyserrulatanoic acid,
isodictyohemiacetal and their derivatives, sester terpenes such as
e.g. dysideapalaun acid, dalvisyriacolide, salvileucolide methyl
ester, epoxyhydroxyoxoophiobol adienal, oxoophiobola tetraenal,
ophiobolin A, ophiobolin G, dihydroxyscalarenolide and/or scalarin
as well as their derivatives, triterpenes such as e.g.
dipterocarpol, hydroxydammarenone II, dammarenolic acid,
tirucallol, ursonic acid, oleanonic acid, isomasticadienonic acid,
fusidinic acid, acetoxydihydroxyfusidadienoic acid, helvolinic
acid, masticadienonic acid, diacetoxy-dioxofusidadienoic acid,
trihydroxycycloartenic acid, pineapple acid, passiflorin,
acetoxytrihydroxy-cucurbitadiene trione, cucurbitacin B,
cucurbitacin F, ursolic acid, pentahydroxycucurbitadiene dione,
hydroxyursanic acid, hydroxyursenic acid, pomolic acid,
hydroxyoleanenoic acid, dihydroxyursenic acid, boswellinic acid,
hydroxyursenic acid and/or hydroxyoxoursenic acid and their
derivatives, whereby the components listed may also be present as a
mixture and must not be understood to represent a limiting choice.
Resin acids, in particular neoabietic acid, levopinaric acid,
pimaric acid, isopimaric acid, abietic acid, dehydroabietic acid,
dihydroabietic acid, sylvic acid, palustric acid and/or colophony
are particularly preferred.
[0018] The organic component should have a melting point,
determined by DSC (DIN 51007, of approximately -20 to 250.degree.
C., in particular of approximately 0 to 200.degree. C. and
particularly preferably of approximately 50 to 180.degree. C. If
the organic component has a melting range and not an actual melting
point, the average temperature of the melting range is used to
determine the melting point. If, for example, no melting point can
be determined because of thermal decomposition, the softening point
or the average temperature of the softening point can be used as an
alternative instead of the melting point. Moreover, the molecular
weight of the organic component should be between approximately 100
and 10,000, in particular between approximately 200 and 5000 and
particularly preferably between approximately 300 and 2500. In the
case of low-molecular compounds, this is typically determined via
the structural formula and in the case of higher molecular products
by means of static light scattering.
[0019] The organic component is typically insoluble or only
slightly soluble in water. In a special embodiment, it is not or
only slightly soluble in acidic to neutral water, the solubility
being less than approximately IC % by weight, preferably less than
approximately 1% by weight and in particular less than 0.1% by
weight. In a further preferred embodiment, the organic component is
partially or completely soluble in dilute caustic soda solution,
the solubility being greater than approximately 0.01% by weight,
preferably greater than approximately 0.1% by weight and in
particular greater than approximately 1% by weight at a pH in the
range of approximately 8 to 12. The solubilities relate to a
temperature of 20.degree. C.
[0020] It is helpful for the water-soluble organic polymeric
protective colloid to form a stable dispersion with the organic
component in aqueous solution, the dispersion still has after 24
hours the same physical properties such as e.g. pH, viscosity,
particle size and colour, and a separation, e.g. settling out of
dispersion particles, does not occur. Since, depending on the type
of organic component, different water-soluble organic polymeric
protective colloids provide the desired dispersion stability, an
organic polymeric protective colloid may be ideal for certain
organic components, whereas an incompatibility may occur with other
organic components. For this reason, the organic polymeric
protective colloid must be matched to the organic component.
Stabilising systems are preferred which allow, in a simple manner,
the aqueous dispersion composition obtained to be converted into
powders which are redispersible in water.
[0021] Typically, suitable water-soluble organic polymeric
protective colloids are preferably higher molecular compounds.
These include natural compounds such as polysaccharides which,
where required, are chemically modified, synthetic higher molecular
oligomers and polymers which have either no or only a slightly
ionic character and/or polymers which are produced in situ by means
of monomers which have at least partially an ionic character, e.g.
by means of radical polymerisation in an aqueous medium. It is also
possible to use only one stabilising system or to combine different
stabilising systems which each other.
[0022] Polysaccharides and polysaccharide ethers soluble in cold
water such as cellulose ethers, starch ethers (amylose and/or
amylopectin and/or their derivatives), guar ethers and/or dextrins
are polysaccharides and their derivatives are preferably used. It
is also possible to use synthetic polysaccharides such as anionic,
nonionic or cationic heteropolysaccharides, in particular xanthan
gum or wellan gum. The polysaccharides may be chemically modified,
but need not be so, e.g. with carboxy methyl groups, carboxyethyl
groups, hydroxyethyl groups, hydroxypropyl groups, methyl groups,
ethyl groups, propyl groups and/or long-chain alkyl groups. Further
natural stabilising systems consist of alginates, peptides and/or
proteins such as e.g. gelatine, casein and/or soya protein.
Dextrins, starch, starch ethers, casein, soya protein, hydroxyalkyl
cellulose and/or alkyl hydroxyalkyl cellulose are particularly
preferred.
[0023] Synthetic stabilising systems may also consist of one or
several protective colloids. As an examples, there is/are one or
several polyvinyl pyrrolidones and/or polyvinyl acetals with
molecular weights of 200 to 400,000, completely or partially
saponified and/or modified polyvinyl alcohols with a degree of
hydrolysis of preferably approximately 70 to 100 mole %, in
particular approximately 80 to 98 mole %, and a Hoppler viscosity
in 4% aqueous solution of preferably 1 to 50 mPas, in particular of
approximately 3 to 40 mPas (measured at 20.degree. C. according to
DIN 53015) and melamine formaldehyde sulphonates, naphthalene
formaldehyde sulphonates, block copolymers of propylene oxide and
ethylene oxide, styrene maleic acid copolymers and/or vinyl ether
maleic acid copolymers. Higher molecular oligomers may be nonionic,
anionic, cationic and/or amphoteric emulsifiers such as e.g. alkyl
sulphonates, alkyl aryl sulphonates, alkyl sulphates, sulphates of
hydroxyl alcanols, alkyl sulphonates and alkyl aryl disulphonates,
sulphonated fatty acids, sulphates and phosphates of
polyethoxylated alcanols and alkyl phenols as well as esters of
sulphosuccinic acid, quaternary alkyl ammonium salts, quaternary
alkyl phosphonium salts, polyaddition products such as
polyalkoxylates, e.g. adducts of 5 to 50 mole ethylene oxide and/or
propylene oxide per mole of linear and/or branched C.sub.6- to
C.sub.22-alcanols, alkyl phenols, higher fatty acids, higher fatty
acid amines, primary and/or secondary higher alkyl amines, the
alkyl groups being preferably a linear and/or branched C.sub.8- to
C.sub.22-alkyl group in each case. Synthetic stabilising systems,
in particular partially saponified, where required, modified,
polyvinyl alcohols are particularly preferred, it being possible
for one or several polyvinyl alcohols to be used together, where
required with small quantities of suitable emulsifiers. Preferred
synthetic stabilising systems are, in particular, modified and/or
unmodified polyvinyl alcohols with a degree of hydrolysis of 80 to
98 mole % and a Hoppler viscosity as 4% aqueous solution of 1 to 50
mPas and/or polyvinyl pyrrolidone. Water-soluble organic polymeric
protective colloids with a higher content of carboxylic acid groups
are, however, less preferred, in particular if they are produced by
means of free radical polymerisation. Thus, the content of
monocarboxylic acids and dicarboxylic acids and their anhydrides
should be less than 50 mole %, preferably less than 25 mole % and
in particular less than 10 mole %. Water-soluble organic polymeric
protective colloids consisting of aromatic sulphonic acid
condensates are, moreover, also less preferred.
[0024] The weight ratio of the organic component to the
water-soluble organic polymeric protective colloid depends above
all on the materials used and the effects to be achieved. It may be
approximately 95:5 to 5:95, in particular approximately 90:10 to
10:90 and preferably approximately 80:20 to 20:80 and particularly
preferably approximately 70:30 to 30:70.
[0025] The pH of the powder redispersible in water amounts, as 10%
aqueous redispersion, typically to approximately 4.5 to 10.5,
preferably approximately 5.0 to 9.5, but can in special cases such
the addition of highly acidic or alkaline components, also be
outside this range.
[0026] The inventive powder redispersible in water may also contain
further additives. The content of additives, based on the sum total
of the organic component and the water-soluble organic polymeric
protective colloid is subject to no critical limits. Thus, it may
be very low and lie within the framework of approximately 0.01% by
weight or more, in particular approximately 0.1% by weight and
preferably approximately 1% by weight in the case of
interface-active substances, for example. On the other hand,
considerably larger proportions of additives can be admixed to the
powder according to the invention, such as e.g. fillers or
film-forming dispersion powders redispersible in water which are
typically obtained by drying synthetically produced film-forming
aqueous polymeric dispersions based on emulsion polymerisation. In
this case, up to approximately 1000 parts, in particular
approximately 500 parts and preferably approximately 100 parts of
further additives can be added per one part of the inventive powder
redispersible in water.
[0027] There are no limits regarding the type of the further
additives. As a rule, they play an important part in the
application of the powder according to the invention, but this is
not essential. It is quite possible to add further organic
polymeric protective colloids, the addition preferably taking place
in the form of a powder in this case.
[0028] Preferred additives consist of pulverous and/or liquid
defoaming agents, wetting agents, alkyl polysaccharide ethers,
hydroxyalkyl polysaccharide ethers and/or alkyl hydroxyalkyl
polysaccharide ethers such as cellulose ether, starch ether and/or
guar ether, the alkyl group and hydroxyalkyl group typically being
a C.sub.1- to C.sub.4- group, synthetic polysaccharides such as
anionic, nonionic or cationic heteropolysaccharides, in particular
xanthan gum or wellan gum, cellulose fibres, dispersing agents,
cement superplasticisers, setting accelerators, early strength
accelerators, setting retarders, air entrainers, polycarboxylates,
polycarboxylate ethers, polyacrylamides, completely and/or
partially saponified and, where required, modified polyvinyl
alcohols, polyvinyl pyrrolidones, polyalkylene oxides and
polyalkylene glycols, the alkylene group being typically a C.sub.2-
and/or a C.sub.3- group, which includes also block copolymers,
dispersions and foam forming dispersion powders redispersible in
water based on copolymers containing emulsion polymers such as e.g.
those based on vinyl acetate, ethylene vinyl acetate, ethylene
vinyl acetate vinyl versatate, ethylene vinyl acetate
(meth)acrylate, ethylene vinyl acetate vinyl chloride, vinyl
acetate vinyl versatate, vinyl acetate vinyl versatate
(meth)acrylate, vinyl versatate (meth)acrylate, all-(meth)acrylate,
styrene acrylate and/or styrene butadiene, hydrophobing agents such
as silanes, silane esters, siloxanes, silicones, fatty acids and/or
fatty acid esters, thickening agents, fillers such as quartzitic
and/or carbonaceous sands and/or flours such as quartz sand and/or
powdered limestone, carbonates, silicates, layer silicates,
precipitated silicic acid, light-weight fillers such as hollow
microspheres of glass, polymers such as e.g. polystyrene spheres,
aluminosilicates, silicon oxide, aluminium silicon oxide, calcium
silicate hydrate, silicon dioxide, aluminium silicate, magnesium
silicate, aluminium silicate hydrate, calcium aluminium silicate,
calcium silicate hydrate, aluminium iron magnesium silicate,
calcium metasilicate and/or volcanic slag as well as pozzolanic
materials such as metakaolin and/or latent hydraulic
components.
[0029] Especially particularly preferred additives are polymer
dispersions, film-forming dispersion powders redispersible in
water, polysaccharide ethers, superplasticisers and hydrophobing
agents, in particular silanes, silane esters, fatty acids, fatty
acid esters and/or oleic acid and their esters as well as other
derivatives.
[0030] The invention relates also to a process for the production
of powders redispersible in water, in particular for the production
of the powders according to the invention, the organic components
being dispersed and stabilised, in a first step, with the
water-soluble organic polymeric protective colloid in water and the
dispersion thus obtained being subsequently dried.
[0031] In this process, it is advantageous, but in no way essential
for the organic component to be mixed in the liquid or viscous form
with the organic polymeric protective colloid pre-dissolved in
water. If the organic component is present in the solid form at
room temperature, it may consequently be useful if it is heated.
However, it is also possible for the organic component, in
particular if it is insoluble in water, to be dissolved or swollen
in an added additive and mixed, in this form, with the aqueous
phase with the organic polymeric protective colloid. Suitable
additives are frequently of a purely organic nature and present in
the liquid form. They consist e.g. of silanes, silane esters,
silicones and/or siloxanes, liquid defoaming agents and/or wetting
agents, low molecular polyalkylene glycols, fatty acids and/or
fatty acid derivatives.
[0032] In principle, all organosilicon compounds can be used as
silanes, silane esters, silicones and/or siloxanes. However, it is
advantageous, though not essential, if they are present in the
liquid form and the boiling point of the organosilicon compounds is
not too low at normal pressure, preferably approximately
100.degree. C. or more. The organosilicon compounds may be soluble,
insoluble or only partially soluble in water. In this respect,
compounds are preferred which have either no or only limited
solubility in water. Silicic acid esters with the formula
Si(OR').sub.4, organoxy silanes with the formula
Si.sub.n(OR').sub.4-n with n=3, polysilanes with the formula
R.sub.3Si(SiR.sub.2).sub.nSiR.sub.3 with n=0 to 500, preferably n=0
to 8, disiloxanes, oligosiloxanes and polysiloxanes of units with
the general formula
R.sub.cH.sub.dSi(OR').sub.e(OH).sub.fO.sub.(4-c-d-e-f)/2 with c=0
to 3, d=0 to 2, e=0 to 3, f=0 to 3 and the sum total of c+d+e+f per
unit being maximum 3.5, R' representing the same or different alkyl
radicals or alkoxy alkylene radicals with 1 to 4 C atoms,
preferably representing methyl or ethyl and R being the same or
different and representing branched or unbranched alkyl radicals
with 1 to 22 C atoms, cycloalkyl radicals with 3 to 10 C atoms,
alkylene radicals with 2 to 4 C atoms, aryl radicals, aralkyl
radicals, alkyl aryl radicals with 6 to 18 C atoms, it being
possible for the radicals R mentioned to be also substituted with
halogens such as F or Cl with ether groups, thioether groups, ester
groups, amide groups, nitrile groups, hydroxyl groups, amine
groups, carboxyl groups, sulphonic acid groups, carboxylic
anhydride groups and carbonyl groups, it being possible in the case
of the polysilanes for R also to have the meaning OR'.
[0033] Preferred organosilicon compounds consist of
tetraalkoxysilanes, alkyl trialkoxysilanes, dialkyl
dialkoxysilanes, it being possible for linear and/or branched
C.sub.1- to C.sub.20-alkyl groups to be used as alkyl groups and
linear and/or branched C.sub.1- to C.sub.10-alkoxy groups to be
used as alkoxy groups, methoxy groups, ethoxy groups and/or
isopropoxy groups being preferably used as the latter. In addition,
it is possible to use also a copolymerisable alkylene group such as
e.g. a vinyl group, allyl group and/or (meth)acrylic group instead
of an alkyl group. Non-limiting examples are vinyl methyl
dialkoxysilane, tetraethoxysilane, methyl tripropoxysilane, methyl
triethoxysilane, .gamma.-chloropropyl triethoxysilane,
.beta.-nitrile ethyl triethoxysilane, .gamma.-mercaptopropyl
triethoxysilane and .gamma.-mercaptopropyl trimethoxysilane, phenyl
triethoxysilane, .pi.-octyl triethoxysilane and isooctyl
triethoxysilane, dipropyl diethoxysilane, triphenyl silanol as well
as their preferably liquid condensation products, where required
with other low-boiling and/or water-soluble silanes such as methyl
trimethoxysilane, .gamma.-amino propyl triethoxysilane or other
silanes containing amino functions, silanes containing quaternary
ammonium salt groups and/or epoxy groups, carboxylic acid
functional silanes and carboxylic anhydride functional silanes,
disilanes such as dimethyl tetraalkoxydisilane, tetramethyl
dialkoxysilane, trimethyl trialkoxydisilane or their
(co)condensates generally obtainable from the corresponding
chlorine compounds. Methyl hydrogen polysiloxanes end blocked by
trimethyl siloxy groups, mixed polymers end blocked by trimethyl
siloxy groups of dimethyl siloxane units and methyl hydrogen
siloxane units and dimethyl polysiloxanes exhibiting in the
terminal units a Si-bonded hydroxyl group are also particularly
preferred.
[0034] In order to disperse the organic component with the
water-soluble organic polymeric protective colloid in water,
average to strong shear forces are usually advantageous and often
also necessary. It can take place batchwise, continuously, e.g. via
static mixers, or semi-continuously both at room temperature and at
elevated temperature. If the organic component has an elevated
melting point and is not dissolved, in this process, in another
liquid substance the dispersion can also take place at temperatures
of more than 100.degree. C., the operation then preferably taking
place at elevated pressure. In order to avoid partial or complete
decomposition of the organic component, it is also possible to
operate under a protective gas atmosphere, where required.
[0035] During the dispersion of the organic component in the
water-soluble organic polymeric protective colloid, it is possible
by the targeted adjustment of the different parameters, to vary in
particular the particle size of the dispersion obtained. This
includes the type and quantity of the water-soluble organic
polymeric protective colloid. In the case of a very small particle
size, a highly efficient distribution of the matrix used is
achieved even with extremely small quantities. If the particle size
is larger, the redispersed material develops its effect over a
longer period. It is consequently frequently preferred to have a
multi-modal particle size distribution at hand in order to have at
hand both a high efficiency and a long-lasting effect. Thus, the
average particle size of the particles dispersed in the dispersion
may typically be between approximately 0.05 and 50 .mu.m, in
particular between approximately 0.1 and 20 .mu.m and preferably
between approximately 1 and 10 .mu.m, it being necessary to ensure
that the particle size is not too large, particularly in the case
of low viscosity dispersions, in order to prevent sedimentation.
This is of less importance in the case of dispersions of higher
viscosity.
[0036] Regarding the solids content of the dispersion of organic
components stabilised with the water-soluble organic polymeric
protective colloid, the invention is subject to no critical limits
at all. However, it is advantageous, as a rule, if the solids
content is approximately 10 to 75% by weight, in particular
approximately 25 to 65% by weight and preferably approximately 40
to 55% by weight. The dispersion obtained moreover typically has a
Brookfield viscosity at 23.degree. C., measured at 23.degree. C.
and 20 rpm according to DIN 53019, of approximately 100 to 50,000
mPas, in particular approximately 500 to 25,000 mPas and preferably
approximately 1000 to 10,000 mPas.
[0037] Drying of the aqueous dispersion obtained preferably takes
place by spray drying, freeze drying, fluid bed drying, drum drying
and/or high speed drying, spray drying being particularly preferred
and it being possible for spraying to take place by means of a
spray wheel, a single or multiple substance nozzle. Where required,
the aqueous solution can in addition be diluted with water in order
to obtain a viscosity suitable for drying. There are basically no
particular limits regarding the drying temperature. However,
particularly for safety considerations, it should, as a rule, not
exceed approximately 200.degree. C., in particular 175.degree. C.
In order to achieve sufficiently efficient drying, temperatures of
approximately 110.degree. C. or higher, in particular approximately
120.degree. C. or higher, are preferred.
[0038] The invention also relates to the process described, the
drying step being omitted. The dispersion thus obtained is then
processed in the liquid state, which is of relevance in particular
in 2-component systems and industrial processing systems, such as
in concrete.
[0039] The process according to the invention also involves the
addition of further additives which, depending on the type and/or
the process technology possibilities, are, as an example, initially
mixed with the organic component and/or with the water-soluble
organic polymeric protective colloid, added to the aqueous
dispersion obtained and/or admixed, as powder, during and/or after
drying to the powder obtained. However, liquid additives can also
be sprayed onto the powder during or after drying. Preferably, the
liquid and/or water-soluble additives are added before, during or
after dispersion and additives in powder form are preferably mixed
during or after drying of the powder obtained. Preferred liquid
and/or water-soluble additives are silanes, silane esters,
siloxanes, fatty acids and/or their derivatives, wetting agents,
defoaming agents, control agents for cement hydration and/or for
adjusting the rheology such as setting retarders, setting
accelerators, cement superplasticisers, cement thickeners, air
entrainers and/or film-forming aqueous polymeric dispersions based
on emulsion polymers. Preferred additives in powder form consist of
fillers, anticaking agents, film-forming dispersion powders
redispersible in water based on emulsion polymers, polysaccharide
ethers such as e.g. cellulose ether, starch ether and/or guar
ether, control agents for cement hydration and/or rheology such as
setting retarders, setting accelerators, cement superplasticisers
and cement thickeners, air entrainers, cellulose fibres, dispersion
agents, polyacrylamides, polycarboxylate ethers, hydrophobing
agents in powder form, in particular based on silanes, silane
esters and/or siloxanes, thickening agents, fillers such as
carbonates, silicates, metakaolins and/or latent hydraulic
components. The proportion of such additives can be very small,
e.g. for interface-active substances and be within the region of
approximately 0.01% by weight or more, in particular approximately
0.1% by weight and preferably approximately 1% by weight, based on
the proportion of additive according to the invention. For other
additives, such as fillers or film-forming dispersion powders
redispersible in water based on emulsion polymers, this may amount
to as much as approximately 1000 parts, in particular approximately
500 parts and preferably approximately 100 parts, based on one part
by weight of the sum total of the organic component and the
water-soluble organic polymeric protective colloid.
[0040] A special embodiment is a process in which the aqueous
dispersion obtained is dried jointly with the film-forming aqueous
polymeric dispersion based on emulsion polymers, film-forming
dispersion powders redispersible in water being obtained which
greatly reduce the efflorescence in hydraulically set systems and,
where required, prevent it completely. In addition, the aqueous
dispersion may, where required, be added also to other dispersions
to be dried, in particular those for rendering the hydraulically
set compounds hydrophobic, e.g. to dispersions based on silanes,
silane esters, siloxanes, silicones, tatty acids and/or fatty acid
esters, after drying hydrophobing agents in powder redispersible in
water being obtained form, which greatly reduce the efflorescence
in hydraulically set systems and, where required, prevent it
completely. In this connection, it is possible to mix the
dispersion to be dried with each before drying and to spray and dry
them jointly or to spray them separately simultaneously via a
two-substance or multiple-substance nozzle and to dry them
subsequently simultaneously with each other. If the other
dispersion to be dried contains a sufficiently high proportion of
water-soluble organic polymeric protective colloid such that free
protective colloid is still available, the organic component may be
dried also jointly with the other dispersion as an
emulsifier-stabilised dispersion. The weight ratio of the organic
component to free protective colloid must be at least approximately
95:5, preferably at least approximately 90:10. However, it is of
advantage if the water-soluble organic polymeric protective colloid
used for the production of the aqueous polymeric dispersion and for
the production of film-forming dispersion powder redispersible in
water is also selected in such a way that the content of
monocarboxylic acids and dicarboxylic acids as well as their
anhydrides is less than 50 mole %. Moreover, aromatic sulphonic
acid condensates are also less preferred. The ratio of the two
dispersions to be dried may be adjusted at random in line with the
effect to be achieved. Thus, the proportion of solids in the
dispersion according to the invention based on the powder dried
jointly, may be approximately 0.1 to 99% by weight, preferably
approximately 1 to 95% by weight and in particular approximately 5
to 80% by weight.
[0041] The powder redispersible in water which is obtained
typically exhibits a high level of wettability and redispersibility
in water. Ideally, it redisperses on mere contact with water within
a few seconds, if need be as a result of light stirring. In certain
cases, it is also possible for somewhat stronger shear forces to be
necessary. In any case, the shear forces occurring during normally
executed mixing processes for dry mortars are as a rule sufficient
to completely redisperse the powder according to the invention and
to achieve a homogeneous distribution in the matrix to be
redispersed. During this process, the particle size of the aqueous
dispersion is obtained again before drying.
[0042] In addition, the invention also relates to the use of a
powder redispersible in water in hydraulically setting systems for
the reduction of efflorescence in hydraulically set systems based
on at least one organic component and at least one water-soluble
organic polymeric protective colloid and, where required, other
additives. The organic component contains at least one compound
with a cyclic group which is completely or partially saturated and
has a melting point of approximately -20 to 250.degree. C. and a
molecular weight of approximately 100 to 10,000, the organic
component being a terpeneoid, an resin acid, colophony, terpene
resin, terpene-phenol resin and/or their derivative and forming a
stable dispersion in water with the water-soluble organic polymeric
protective colloid. The weight ratio of the organic component to
the water-soluble organic polymeric protective colloid is
approximately 95:5 to 5:95. In addition, 0 to approximately 1000
parts by weight, based on one part by weight of the sum total of
the organic component and the water-soluble organic polymeric
protective colloid, at least one film-forming dispersion powder
redispersible in water based on a film-forming dispersion and/or
further additives may be contained therein.
[0043] The invention moreover relates also to the use of an aqueous
dispersion, produced according to the process described above, in
hydraulically setting systems for the reduction of efflorescence in
hydraulically set systems based on at least one organic component
and at least one water-soluble organic polymeric protective colloid
and, where required, further additives. The aqueous dispersion
produced, based on 100 parts by weight of the sum total of the
organic component and the water-soluble organic polymeric
protective colloid, is based on approximately 5 to 95 parts by
weight, preferably approximately 10 to 90 parts by weight, in
particular approximately 20 to 80 parts by weight, of at least one
organic component which contains preferably colophony, abietic
acid, sylvic acid, neoabietic acid, levopinaric acid, pimaric acid,
isopimaric acid and/or palustric acid and/or their derivatives,
based on approximately 5 to 95 parts by weight, preferably
approximately 10 to 90 parts by weight, in particular approximately
20 to 80 parts by weight of at least one water-soluble organic
polymeric protective colloid, this representing at least one
modified and/or unmodified polyvinyl alcohol with a degree of
hydrolysis of approximately 70 to 100 mole %, in particular of
approximately 80 to 98 mole % and a Hoppler viscosity as 4% aqueous
solution of approximately 1 to 50 mPas, in particular of
approximately 3 to 40 mPas (measured at 20.degree. C. according to
DIN 53015) and/or polyvinyl pyrrolidone, and/or approximately 20 to
90 parts by weight, preferably approximately 25 to 90 parts by
weight, of water-soluble organic polymeric protective colloid, this
representing at least one natural and/or synthetically produced
biopolymer, which, where required, is synthetically modified and is
in particular starch, starch ether, dextrins, cellulose ether,
casein and/or soya protein. In addition, 0 to approximately 500
parts by weight, preferably 0 to approximately 250 parts by weight,
of at least one silane component and/or siloxane component as well
as 0 to approximately 10,000 parts by weight, preferably
approximately 0 to 2000 parts by weight of a film-forming aqueous
polymeric dispersion, based on 100 parts by weight of the sum total
of the organic component and the water-soluble organic polymeric
protective colloid respectively may be contained therein. The
proportion of solids of the aqueous dispersion is between
approximately 10 and 70% by weight, in particular between
approximately 25 and 65% by weight and preferably between
approximately 40 and 55% by weight, the average particle size of
the dispersed particles is between approximately 0.05 and 50 .mu.m,
in particular between approximately 0.1 and 20 .mu.m and preferably
between approximately 1 and 10 .mu.m and the Brookfield viscosity
amounts to approximately 100 to 50,000 mPas and preferably
approximately 250 to 25,000 mPas and in particular approximately
500 to 10,000 mPas.
[0044] The inventive powder redispersible in water and the
non-dried aqueous dispersion are preferably used in hydraulically
setting compounds, in particular in concretes and dry mortars. Such
dry mortar formulations contain, apart from the powder according to
the invention, in particular at least one hydraulically setting
binder and typically further mortar formulation additives, such as
e.g. fillers such as sand, silicates and/or carbonates, organic
binders such as film-forming dispersion powders redispersible in
water based on emulsion polymers and/or polyvinyl alcohol, rheology
control additives such as polysaccharide ether, casein,
superplasticisers and/or thickeners and/or hydration control
additives such as accelerators and/or retarders. The hydraulically
setting binder is Portland cement, e.g. according to EN 196 CEM, I,
II, ITT, IV and V, calcium sulphate in the form of
.alpha.-hemi-hydrate and/or .beta.-hemi-hydrate and/or anhydrite,
high alumina cement and/or lime, usually in the form of calcium
hydroxide and/or calcium oxide. Portland cement, high alumina
cement and/or calcium sulphate are preferred. The proportion of
powder according to the invention is in this case 0.01 to 25% by
weight, in particular approximately 0.1 to 10% by weight and
preferably approximately 0.2 to 5% by weight, based on the
hydraulically setting binder. If the non-dried aqueous dispersion
is used, it can be added to the hydraulically setting formulation
either as such and/or together with liquid polymer dispersions
and/or other liquid additives either together with the mixing water
or separately.
[0045] The dry mortars containing the powder according to the
invention are preferably used where the applied and dried mortars
may come into more or less regular contact with water. Apart from
typical applications in the open air such e.g. thermal insulation
mortars, sealing compounds, gypsum- and/or lime and/or cement
plasters, spray and/or repair mortars, spray and/or repair
concretes as well as polymer cement concretes (PCC) and/or polymer
cement spray concretes (S-PCC), these consist of tile grout
adhesives, plywood mortars, bonding agent mortars, cementitious
parquet adhesives, cement sizings, tile adhesives, levelling and/or
trowelling compounds. In addition, the powders according to the
invention and the non-dried aqueous dispersions can be used as
concrete additive and/or as additive for a protective coating on
concrete.
[0046] In this respect, it is highly advantageous for the powder
according to the invention and the dispersion according to the
invention, apart from greatly reducing efflorescence, to behave in
a rheology neutral manner in the hydraulically setting systems and
in the quantities used, in particular if synthetic stabilising
systems are employed. Moreover, the setting behaviour of the
hydraulically setting system is influenced either not at all or
only insignificantly. The good mixing behaviour, good wettability
and easy processability of the mortar and concrete are also of
great importance. Moreover, the hydrophobicity is also improved in
many cases, which, as a rule, is a welcome additional effect.
[0047] Moreover, it is also possible to use the powder according to
the invention and/or the aqueous dispersion produced according to
the process described in adhesives. In this case, it is
particularly advantageous to use the powder in powder adhesives, in
particular in cases where a high cohesion is desired as early as
during the early drying phase.
[0048] The invention is explained by way of the following
examples.
A) Production of Aqueous Dispersions and of Powders Redispersible
in Water
EXAMPLE 1
Production of Powder 1
[0049] 100 g of a 20% polyvinyl alcohol solution with a degree
hydrolysis of 88 mole % and a Hoppler viscosity, as 4% solution, of
4 mPas were heated to 85.degree. C. in a 500 ml glass vessel with a
propeller stirrer with stirring at 100 rpm. Subsequently 20 g of
solid colophony (Fluka) were added slowly, the colophony being
dispersed completely. A stable, light yellowish dispersion with a
solids content of 33% by weight, a Brookfield viscosity at
23.degree. C. of 10,000 mPas at 20 rpm and an average particle size
of the dispersed particles of 9 .mu.m which can be modified simply
by changing the process parameters, was obtained. The dispersion
obtained was dried without further additives by conventional spray
drying at an initial temperature of 125.degree. C. to form a
yellowish, free-flowing powder redispersing in water, whereby no
contamination worth mentioning was observed in the spray tower and
the yield was within the normal range.
EXAMPLE 2
Production of Powder 2
[0050] Example 1 was repeated, although 46.7 g of solid colophony
was added. A stable, light yellowish dispersion with a proportion
of solids of 45% by weight, a Brookfield viscosity at 23.degree. C.
of 1,000 mPas and 20 rpm and an average particle size of 8 .mu.m
which could be modified simply by modifying the process parameters,
was obtained. After spray drying, a yellowish, free-flowing powder
redispersible in water was obtained, whereby no contamination worth
mentioning was observed in the spray tower and the yield was within
the normal range.
EXAMPLE 3
Production of Powder 3
[0051] 25.0 g of solid colophony were dissolved at room temperature
in 25.0 g of a liquid alkyl triethoxysilane with stirring in a 100
ml vessel. A stable, low-viscosity, yellowish solution was
obtained. The solution was added slowly at room temperature with
stirring to 375 g of a 20% polyvinyl alcohol solution with a degree
of hydrolysis of 88 mole % and a Hoppler viscosity, as 4% solution,
of 4 mPas in an 800 ml glass vessel. A light yellowish dispersion
with a proportion of solids of 29% by weight was obtained which was
adjusted to a pH of 7 with 0.1N caustic soda solution and
subsequently spray dried as in example 1. A yellowish, free-flowing
powder redispersible in water was obtained, whereby no
contamination worth mentioning was observed in the spray tower and
the yield was within the normal range.
EXAMPLE 4
Production of Powder 4
[0052] 28 g of the dispersion produced according to example 1 were
added to 73 g of an EVA-dispersion with a solids content of 51% by
weight and a glass transition temperature T.sub.g of -3.degree. C.
and subsequently spray dried as in example 1A yellowish
free-flowing powder redispersible in water was obtained, whereby no
contamination worth mentioning was observed in the spray tower and
the yield was within the normal range.
COMPARATIVE EXAMPLE 5
Production of Powder 5
[0053] Example 1 was repeated, although 20 g of solid stearic acid
(Fluka) were added to the polyvinyl alcohol solution instead of
colophony. A white dispersion with a proportion of solids of 33% by
weight was obtained which was subsequently dried as in example 1 to
form a white, free-flowing powder redispersible in water.
COMPARATIVE EXAMPLE 6
Production of Powder 6
[0054] Example 1 was repeated, although 20 g of carnauba wax
(Merck; consisting of approximately 85% wax esters) were added to
the polyvinyl alcohol solution instead of colophony. A light
yellowish dispersion with a proportion of solids of 33% by weight
was obtained which was subsequently dried as in example 1 to form a
light yellowish, free-flowing powder redispersible in water.
EXAMPLE 7
Production of Powder 7
[0055] 30 g of solid polyvinyl pyrrolidone (PVP-K90; Fluka) and 90
g of water were heated to 85.degree. C. in a 500 ml glass vessel
with a propeller stirrer with stirring at 1000 rpm. After the
polyvinyl pyrrolidone had dissolved, 30 g of solid colophony
(Fluka) were added slowly, the colophony being dispersed
completely. A stable, light yellowish dispersion with a proportion
of solids of 40% by weight, a Brookfield viscosity at 23.degree. C.
of 10,000 mPas at 20 rpm and an average particle size of 3.7 .mu.m
which could be simply modified by modifying the process parameters,
was obtained. The dispersion obtained was dried without further
additives by conventional spray drying at an initial temperature of
125.degree. C. to form a yellowish, free-flowing powder
redispersing in water, whereby no contamination worth mentioning
was observed in the spray tower and the yield was within the normal
range.
EXAMPLE 8
Production of Powder 8
[0056] To 200 g of a commercially obtainable aqueous dispersion
stabilised with anionic emulsifiers and based on a modified
colophony and with a proportion of solids of 30% by weight were
added 24 g of a 25% polyvinyl alcohol with a degree hydrolysis of
88 mole % and a Hoppler viscosity, as 4% solution, of 4 mPas, with
stirring. A stable, light yellowish dispersion with a solids
content of 29.5% by weight was obtained. The dispersion obtained
was dried without further additives by conventional spray drying at
an initial temperature of 125.degree. C. to form a yellowish,
free-flowing powder redispersible in water, whereby no
contamination worth mentioning was observed in the spray tower and
the yield was within the normal range.
EXAMPLE 9
Production of Powder 9
[0057] To 150 g of an aqueous dispersion stabilised with polyvinyl
alcohol and based on vinyl acetate/vinyl versatate with a
proportion of solids of 40.5% by weight, 30 g of a commercially
obtainable aqueous solution stabilised with amphoteric emulsifiers
and based on a modified colophony and with a proportion of solids
of 30% by weight and 30 g of a 25% polyvinyl alcohol solution with
a degree of hydrolysis of 88 mole % and a Hoppler viscosity, as 4%
solution, of 4 mPa were added. 1.5 g of a defoaming agent were
added to the dispersion thus obtained. Subsequently, dilution was
carried out with water to a solids content of 25% by weight. The
dispersion thus obtained was dried by conventional spray drying at
an initial temperature of 125.degree. C. to form a light yellowish,
free-flowing powder redispersible in water, whereby no
contamination worth mentioning was observed in the spray tower and
the yield was within the normal range.
EXAMPLE 10
Production of Dispersion 1
[0058] 10 g of abietic acid (Fluka) were dissolved in 20 g of
spirit of turpentine (Fluka). A slightly viscous and slightly
turbid solution was obtained. The solution was added slowly with
stirring at room temperature to 150 g of a 20% polyvinyl alcohol
solution with a degree of hydrolysis of 88 mole % and a Hoppler
viscosity, as 4% solution, of 4 mPas. A stable, whitish dispersion
with a solids content of 33% by weight was obtained. The dispersion
obtained was used directly in the mortar mixture.
COMPARATIVE EXAMPLE 11
Production of Dispersion 2
[0059] 10 g of naphthyl acetic acid (Fluka) were dissolved in 10 g
of acetone. The solution was added slowly with stirring at room
temperature to 50 g of a 20% polyvinyl alcohol solution with a
degree of hydrolysis of 88 mole % and a Hoppler viscosity, as 4%
solution, of 4 mPas. A stable, whitish dispersion with a solids
content of 43% by weight was obtained. The dispersion obtained was
used directly in the mortar mixture.
B) Technical Application Tests Using Different Cementitious
Compounds
APPLICATION EXAMPLE 1
[0060] 35.0 parts of white Portland cement, 19.2 parts of quartz
sand (0.08-0.2 mm), 41.0 parts of calcium carbonate Durcal 65, 0.3
parts of a cellulose ether (viscosity as 2% aqueous solution: 3200
mPas), 2.0 parts of the pigment Bayferrox 110 and 1.0 parts of
construction lime were thoroughly mixed and used as basic dry
mortar formulation. To this, different powders were added in
varying quantities as shown in table 1, which could be stirred
simply into the mortar matrix without further special mixing
processes. The formulations were mixed in each case with 32 parts
of water, based on 100 parts of dry formulation, using a 60 mm
propeller stirrer operating at a rate 950 rpm for 60 seconds, the
quantity of mixing water indicated being added with stirring. After
a maturing time of 3 minutes, the mortar was briefly stirred again
by hand and applied by means of a serrated trowel onto an stoneware
tile of a thickness of 6 mm to an area of (196 mm.times.50 mm), the
tiles having been saturated with water immediately beforehand. Two
different samples were produced in each case, the mortar having
been applied by means of spacer rails in a layer thickness of 2.2
mm (1.0 mm respectively).
[0061] The test specimens were subsequently mounted immediately to
a container with water in a climatic chamber cooled to 7.degree.
C., the water being warmed to a constant 20.degree. C. The
container was designed in such a way that the test specimens were
lying at least 5 cm above the water surface and had an inclination
at an angle of 45.degree.. The surface area not covered by the test
specimens was covered and isolated such that water vapour
penetrates through the carrier material into and through the test
specimens. After a storage period of 7 days, the surface was
assessed optically for efflorescence (eye and microscope).
TABLE-US-00001 TABLE 1 Technical application examples using a
pigmented cementitious trowelling compound with a thickness of 2.2
mm for assessing efflorescence. Basic Quantity recipe used.sup.b)
[% by Powder/ by [% Test no. weight] disp..sup.a) No. weight]
Efflorescence B-1 100 N/A N/A 0 Extremely (Reference) strong B-2
99.8 P 1 0.2 None B-3 99.6 P 3 0.4 None B-4 98.0 P 4 2.0 None B-36
99.6 P 7 0.4 None B-38 99.6 P 8 0.4 None B-39 99.8 P 8 0.2 None
B-40 99.8 D 1 0.2 None B-41 99.9 D 1 0.1 None B-42 98.0 P 9 2.0
None B-5 (comp) 99.8 P 5 0.2 Extremely strong B-6 (comp) 99.6 P 5
0.4 Extremely strong B-7 (comp) 99.8 P 6 0.2 Extremely strong B-8
(comp) 99.6 P SEAL80.sup.c) 0.4 Strong B-9 (comp) 99.8 P
SEAL80.sup.c) 0.2 Strong .sup.a)"P" represents powder, "D"
dispersion. .sup.b)In the case of powders, the quantity used
relates to the quantity of powder employed, in the case of
dispersions to the solids content of the dispersion. .sup.c)Elotex
Seal80 is a redispersible hydrophobing agent based on a special
silane and polyvinyl alcohol. The mortar processability was good in
the case of all the specimens and the mortar consistency comparable
to the reference respectively.
[0062] The results clearly show that all colophony-containing
specimens suppressed the efflorescence so strongly or even
eliminated them completely such that none could be observed even
under the microscope. The reference specimens, on the other hand,
exhibited very strong efflorescence.
APPLICATION EXAMPLE 2
[0063] Samples produced in a manner analogous to those of the
application example 1 were stored for 7 days at 23.degree. C. and a
relative humidity of 50%. To assess the hydrophobicity, the time
was subsequently determined, which passed until 5 drops of water
(approximately 0.2 g) had disappeared from the surface.
TABLE-US-00002 TABLE 2 Technical application examples using a
pigmented cementitious trowelling compound in a layer thickness of
2.2 mm for assessing hydrophobicity. Basic Quantity recipe
used.sup.b) [% by Powder/ by [% Test no. weight] disp..sup.a) No.
weight] Time [min] H-1 100 P N/A 0 Immediately (Ref.) H-2 99.6 P 2
0.4 240 H-3 99.8 P 2 0.2 20 H-4 99.6 P 5 0.4 Immediately (comp) H-5
99.8 P SEAL80.sup.c) 0.2 150 (comp) H-6 99.6 P SEAL80.sup.c) 0.4
370 (comp) .sup.a), b), c)compare Table 1.
[0064] The data in Table 2 show the excellent hydrophobing
properties of Elotex Seal80, although this provides no or only a
slight reduction of efflorescence (compare other examples). The
powders according to the invention, on the other hand, exhibit also
a good mortar hydrophobicity with a rising proportion, apart from a
strong reduction of the efflorescence. Powder 5 containing stearic
acid, which is well known to be a hydrophobing agent, however,
exhibits neither hydrophobicity nor a reduction of the
efflorescence.
APPLICATION EXAMPLE 3
[0065] Application example 1 was repeated, the layer thickness
being adjusted to 1.0 mm.
TABLE-US-00003 TABLE 3 Technical application examples using a
pigmented cementitious trowelling compound with a thickness of 1.0
mm for assessing efflorescence. Basic Quantity recipe used.sup.b)
[% by Powder/ [% by Test no. weight] disp..sup.a) No. weight]
Efflorescence B-10 100 P N/A 0 Strong (Reference) B-11 99.8 P 1 0.2
None B-12 99.6 P 3 0.4 None B-13 98.0 P 4 2.0 None B-43 99.6 P 7
0.4 None B-44 99.8 P 7 0.2 None B-45 99.8 D 1 0.2 None B-46 99.9 D
1 0.1 None B-47 99.6 P 8 0.4 None B-48 99.8 P 8 0.2 None B-49 98.0
P 9 2.0 None B-14 (comp) 99.8 P 5 0.2 Strong B-15 (comp) 99.6 P 5
0.4 Strong B-16 (comp) 99.8 P 6 0.2 Strong B-17 (comp) 99.6 P
SEAL80.sup.c) 0.4 Little B-18 (comp) 99.8 P SEAL80.sup.c) 0.2
Strong .sup.a), b), c)compare Table 1.
[0066] The results show a clear reduction in efflorescence also in
thinly applied mortars insofar as a powder according to the
invention or a dispersion to the invention is used. Powder 4 in
experiment No B-13 clearly shows also that the powder according to
the invention can also be added to film-forming dispersion powders
redispersible in water based on emulsion polymers, for example, and
can be used as such in mixture.
APPLICATION EXAMPLE 4
[0067] 28.0 parts of white Portland cement, 25.0 of quartz sand
0.1-0.3 mm, 8.0 parts of sand 0.7-1.2 mm, 35.0 parts of sand
1.5-2.2 mm, 0.05 parts of a cellulose ether (viscosity as 2%
aqueous solution: 15,000 mPas) and 2.0 parts of the pigment
Bayferrox 110 were thoroughly mixed and used as a basic dry mortar
formulation. The formulations were mixed with 18 parts of water,
based on 100 parts of dry formula, respectively, and tested in a
manner analogous to application example 1
TABLE-US-00004 TABLE 4 Technical application examples using a
decorative pigmented render in a layer thickness of 2.2 mm for
assessing efflorescence. Basic Quantity recipe used.sup.b) [% by
Powder/ by [% Test no. weight] disp..sup.a) No. weight]
Efflorescence B-19 100 P N/A 0 Very strong (Reference) B-20 99.8 P
1 0.2 None B-21 99.8 P 3 0.2 None B-22 98.0 P 4 2.0 None B-50 99.6
P 7 0.4 None B-51 99.8 P 7 0.2 None B-52 99.8 D 1 0.2 None B-53
99.9 D 1 0.1 None B-54 (comp) 99 D 2 1 Very strong B-55 (comp) 99.5
D 2 0.5 Very strong B-56 99.6 P 8 0.4 None B-57 99.8 P 8 0.2 None
B-58 98.0 P 9 2.0 None B-23 (comp) 99.8 P 5 0.2 Very strong B-24
(comp) 99.6 P 5 0.4 Very strong B-25 (comp) 99.8 P 6 0.2 Very
strong B-26 (comp) 99.6 P SEAL80.sup.c) 0.4 Strong .sup.a), b),
c)compare Table 1. The mortar processability was equally good in
the case of all specimens and the mortar consistency comparable in
each case with the reference.
[0068] The results listed demonstrate that the strong reduction of
the efflorescence occurs also in a decorative pigmented render.
APPLICATION EXAMPLE 5
[0069] 40.0 parts of white Portland cement, 3 parts of aluminate
cement, 50.0 parts of quartz sand 0.1-0.3 mm, 2 parts of a
hydrophobic, film-forming dispersion powder redispersible in water
and based on an emulsion polymers (Elotex WS45), 1 part of
cellulose fibre, 0.10 parts of tartaric acid and 2.0 parts of the
pigment Bayferrox 110 and 1.0 part of construction lime were
thoroughly mixed and used as basic dry mortar formulation. The
formulations were mixed with 22 parts of water, based on 100 parts
of dry formulation, in each case, and tested in a manner analogous
to application example 1.
TABLE-US-00005 TABLE 5 Technical application examples using a joint
mortar in a layer thickness of 2.0 mm for assessing efflorescence.
Basic Quantity recipe used.sup.b) [% by Powder/ by [% Test no.
weight] disp..sup.a) No. weight] Efflorescence B-27 100 P N/A 0
Strong (Reference) B-28 99.6 P 2 0.4 None B-29 99.8 P 2 0.2 None
B-30 99.6 P 3 0.4 None B-31 (comp) 99.6 P SEAL80.sup.c) 0.4 Strong
.sup.a), b), c)compare Table 1. The mortar processability was
equally good in the case of all specimens and the mortar
consistency comparable to the reference in each case.
[0070] The results listed demonstrate that the strong reduction of
the efflorescence occurs also in a joint mortar.
APPLICATION EXAMPLE 6
[0071] 32.0 parts of white Portland cement, 1 part of aluminate
cement, 65.0 parts of quartz sand (0-0.2 mm), parts of calcium
sulphate, 0.75 parts of a hydrophobic, film-forming dispersion
powder redispersible in water and based on an emulsion polymers
(Elotex HD1501), 0.25 parts of a superplasticisers based on
melamine sulphonate, 0.1 part of a defoaming agent in powder forms
0.5 parts of black iron oxide and 0.05 parts of a cellulose ether
(viscosity as 2% aqueous solution: 4000 mPas) were thoroughly mixed
and used as basic dry mortar formulation. The formulations were
mixed with 17.5 parts of water, based on 100 parts of dry
formulation, in each case, and tested in a manner analogous to
application example 1.
TABLE-US-00006 TABLE 6 Technical application examples using a joint
mortar in a layer thickness of 2.0 mm for assessing efflorescence.
Basic Quantity recipe used.sup.b) [% by Powder/ by [% Test no.
weight] disp..sup.a) No. weight] Efflorescence B-32 100 P N/A 0
Very strong (Reference) B-33 99.8 P 2 0.2 None B-34 99.6 P 3 0.4
None B-35 (comp) 99.6 P SEAL80.sup.c) 0.4 Strong .sup.a), b),
c)compare Table 1. The mortar processability was equally good in
the case of all specimens and the mortar consistency comparable to
the reference in each case.
[0072] The results listed demonstrate that the strong reduction or
even the total prevention of efflorescence occurs not only in
different joint mortars, but also in a wide varieties of different
mortars. Surprisingly enough, only a very small proportion of these
additives is used for this purpose, which has no or only a very
minor effect on the other mortar properties--be it in fresh mortar
or in the set state.
[0073] Although the colophony used is classified as a hazardous
substance, the hazards potential is reduced by the encapsulation of
the colophony with polyvinyl alcohol. Moreover, handling usually
causes essentially fewer problems since the powder is free-flowing
and consequently conveying, metering and mixing can be carried out
without major effort and often be automated.
* * * * *