WO2013044980A1

WO2013044980A1 - Curable mixture

Info

Publication number: WO2013044980A1
Application number: PCT/EP2011/067128
Authority: WO
Inventors: Ulf Kehrer
Original assignee: Akzo Nobel Chemicals International B.V.
Priority date: 2011-09-30
Filing date: 2011-09-30
Publication date: 2013-04-04

Abstract

The present invention relates to a curable mixture comprising - more than 25 wt.% of one or more mineral binders, based on the total amount of the curable mixture, - 0.001 to 8 wt.% of one or more fluoroorganic-substituted silicon compounds, which is adsorbed on a solid, based on the total amount of the curable mixture, and - optionally further added substances, as well as to the cured mixture, processes for the preparation of the curable and the cured mixture and their use. The cured mixture has excellent hydrophobic and oleophobic and therefore excellent dirt repellent, i.e. easy-to-clean properties.

Description

CURABLE MIXTURE

The present invention relates to a curable mixture and its preparation, a cured mixture and its preparation, as well as to the use of the curable mixture and to the use of a fluoroorganic-substituted silicon compound, which is adsorbed on a solid, in the curable mixture, wherein the cured mixture has excellent hydrophobic and oleophobic - and therefore excellent dirt-repellent, i.e. easy-to- clean - properties. Curable mixtures such as mineral setting materials, for instance hydraulically setting materials, e.g. cement bound materials, are widely used in the modern building and construction industry in numerous places. Non-limiting examples are concrete paving tiles for driveways, doorways, pavements, terraces, for grouts and any type of surface coatings such as plasters and renders.

A big problem is soiling of the surfaces of these materials, outdoors as well as indoors. They can be stained by various substances such as traffic and industry fumes, in particular soot, pollen, grassy flecks, oils, in particular motor oils, cosmetics and makeup, residues of meals and drinks such as Coca Cola, coffee, red wine or ketchup, as well as growth of microorganisms such as algae or fungi. All these stains are a big problem from an aesthetic point of view. Therefore, it is desirable to equip cured mixtures, in particular hydraulically set building and construction materials, which are used in such applications and which might be exposed to such stains, with hydrophobic and oleophobic - and thus dirt- repellent - properties. Such properties are also summarized under the term "easy-to-clean" or for short "ETC".

The skilled person understands dirt repellent properties to mean int. al. the property of the surface to prevent the penetration of aqueous as well as oily substances into the material and to facilitate the removal of these substances from the surfaces. Furthermore, paints, coating, lacquers, dusts as well as growths of various materials such as moss and algae can be removed easily. The testing of the staining properties is suitably carried out by measuring the water and oil repellency and/or according to DIN EN ISO 10545-14. Thus, materials having such easy-to-clean properties must be not only water-repellent, i.e. hydrophobic, but also oil-repellent, i.e. oleophobic.

It is known from the prior art that in particular inorganic substrate surfaces can be equipped with easy-to-clean properties by post-treatment of the cured surfaces with a fluoroorganic-substituted silicon compound. However, an additional working step is required for this operation, which is costly. Furthermore, if the substrate surface which is treated in this way is damaged e.g. by abrasion or cracks, the easy-to-clean properties deteriorate.

EP 1 262 464 discloses a grout powder for admixture with water to produce grouts. The grout powder comprises cement powder. At least one component, e.g. the cement powder or the quartz particles of the grout powder, is first treated on its surface with a fluorochemical compound, e.g. a silane. The manufacture of this grout powder comprising ingredients which are treated with a fluorochemical compound is complex and comprises - among others - the treatment of the cement-containing mixture with water, organic solvents, and the fluorochemical compound, followed by drying and homogenizing. The thus obtained pre-treated grout powder- after mixing with water, application, and curing - shows oil- and water-repellent properties. However, since at least one component of the grout powder has been pre-treated with a fluorochemical compound, such mortars show hydrophobic properties already upon addition of water and mixing therewith. Thus, the wettability of these mixtures is poor, leading to problems of homogenizing the mortar.

It was therefore the objective of the present invention to provide a curable mixture where the curable as well as the cured mixture can be obtained with as few as possible, preferably simple, working steps. Furthermore, the cured mixture must exhibit high compressive strengths and sufficient dirt-repellent properties of the surface, and in particular of abraded, damaged, and cracked surfaces, which have to be most durable.

Surprisingly, it was now found that the problem can be solved with a curable mixture comprising

- more than 25 wt.%, preferably more than 25 to 60 wt.%, most preferably 26 to 45 wt.%, of one or more mineral binders, based on the total of the curable mixture,

- 0.001 to 8 wt.% of one or more fluoroorganic-substituted silicon compounds which are adsorbed on a solid, based on the total of the curable mixture, and

- optionally further added substances.

The amounts of the added components are based on the total of the curable mixture and thus relate - unless specified otherwise - to the water-free part, i.e. generally to the dry proportion including the fluoroorganic-substituted silicon compounds which are adsorbed on a solid, of the respective components and are given in parts by weight, i.e. in wt.%. Furthermore, they sum up to 100 wt.%.

Surprisingly, it was found that the mixture according to the invention is suitable to provide the cured mixture with excellent hydrophobic as well as oleophobic - and thus easy-to-clean - properties, even with very small amounts of a fluoroorganic- substituted silicon compound. The mixture according to the invention is easy to manufacture and process further. Typically, it is in the form of a powder or granules. The fluoroorganic-substituted silicon compound which is adsorbed on a solid is distributed homogeneously in the curable mixture and is not very sensitive to traces of moisture which would enter during storage of the mixture. After the mixture is mixed with water and cured, the total mass of the cured mixture reveals excellent hydrophobic as well as oleophobic properties. This is most important when the surface becomes damaged by e.g. abrasion or cracks. Furthermore, it was found that despite the pronounced hydrophobic and oleophobic properties of the cured mixture, the curable mixture has a good wettability with water. Additionally, the adhesion of the cured mixture to the various surfaces is sufficiently high for at least most applications, which is contrary to what the skilled person in the art expects. Moreover, due to the high content of mineral binder, i.e. more than 25 wt% based on the water-free mixture, increased compressive strengths of the cured mixture can be obtained. This is of particular advantage for the production of mortars, which, in comparison to concrete, have a higher number of pores, in particular air pores.

The use of the fluoroorganic-substituted silicon compound according to the invention was found to have a benefit when compared to conventional silanes. Conventional silanes, i.e. silicon compound, often have an undesired liquefying effect on mortar preparations. The fluoroorganic-substituted compounds of the invention surprisingly do not influence the viscosity, especially any thixotropic behaviour, negatively. Therefore, the yield point of the curable mixture mixed with water is not or only slightly influenced by the addition of the fluoroorganic- substituted silicon compound.

Also claimed are processes to make the curable mixture of the invention. In one embodiment, the curable mixture is obtained by mixing a fluoroorganic- substituted silicon compound which is adsorbed on a solid with at least one component of the curable mixture. By doing so, it is possible to make one- component dry mortars, which easily can be stored and transported. On the building site, they only need to be mixed with water and applied in order to reveal the advantageous properties in the cured state. However, it is also possible to prepare two-component mortars comprising a dry part which is free of water comprising the fluoroorganic-substituted silicon compound which is adsorbed on a solid, and a liquid component comprising the water required to obtain the desired water/cement ratio. The thus obtained cured mixtures are obtained in an easy manner and show the advantageous easy-to-clean properties. In another embodiment, the curable mixture is made by a process wherein in a first step a component (i) comprising the mineral binder and a component (ii) comprising the fluoroorganyl-substituted silicon compound which is adsorbed on a solid are prepared. The further added substances are mixed with components (i) and/or (ii). In a second step the components (i) and (ii) are mixed with one another. With this process it is possible to make mortars of the invention from two or more components.

Claimed also is a process to make the cured mixture of the invention, comprising the step of mixing the curable mixture of the invention and/or the curable mixture prepared according to the processes of the invention with 1 to 120 wt.% water, based on 100 wt.% of curable, water-free mixture. Hence, the two or more components can be mixed together on the building site without the need to add further water. Alternatively, dry mortars can be mixed with water from e.g. a water pipe. Afterwards, the obtained mixture can be applied onto e.g. a substrate or processed into a form such as a precast form, and allowed to cure. The thus obtained cured mixture is obtained in an easy manner and shows the desired easy-to-clean properties.

The invention further provides the cured mixture having hydrophobic and oleophobic properties obtainable according to said processes of the invention.

The hydrophobic and oleophobic properties are determined as follows. In a first step a specimen consisting of the cured mixture having an even surface, e.g. a prism having the mass of 8 x 4 x 4 cm, is prepared without any form oil according to EN 12808-5. After one day, the prism is stripped. After a total of 28 days at standard conditions (23°C/ 50% RH), the contact angle of water (to determine the hydrophobicity) and of olive oil (to determine the oleophobicity), respectively, is measured. To this end a drop (ca. 0.2 ml) of the respective liquid is placed onto the surface of the mortar. Two minutes after the drop has been placed, the contact angle is measured optically using a contact angle measuring device with a camera (e.g. type DSA100 of Kruss). The analysis can be made with the device-specific software. The surface possesses hydrophobic (water drop) and oleophobic (olive oil drop) properties in accordance with the invention, respectively, when a contact angle of at least 60°, preferably at least 70°, in particular at least 80°, is measured.

With the processes of the invention it is possible to provide the curable mixture as well as the cured mixture in a surprisingly easy and economical manner, using known agitators in traditional containers and mixers.

The mixture made according these processes after curing possesses the mentioned, advantageous easy-to-clean properties not only on the surface, but in the total mass. Thus, they are mass-hydrophobized and mass-oleophobized.

It was surprising that the fluoroorganic-substituted silicon compound can - on the one hand - be absorbed on a solid to obtain a stable mixture with known processes and materials. On the other hand, it was not to be expected that the adsorbed fluoroorganic-substituted silicon compound in the curable mixture with such a high proportion of mineral binder is stable enough to be mixed into a stable composition, even more so since hydraulic binders have a strongly basic reaction upon contact with water. Additionally, it was particularly surprising to find that the fluoroorganic-substituted silicon compound adsorbed on the solid is hydrophilic enough - when the mixture containing the same is mixed with water - to desorb from the solid, followed by hydrolysis and further reactions, e.g. condensation.

In order to obtain in the cured mixture the desired easy-to-clean properties, the various complex processes and reactions need to occur at the right time. Based on conventional knowledge, it is expected that, in order to obtain the favoured modification of the total mass, i.e. mass modification, the fluoroorganic- substituted silicon compound needs to be distributed homogeneously. Also, it is expected that when the curable mixture is mixed with water, it is essential that the fluoroorganic-substituted silicon compound desorbs from the solid, i.e. carrier, at the right time and thus is released. This is based on the expectation that when the fluoroorganic-substituted silicon compound is adsorbed too strongly on the solid, the silicon compound hydrolyzes and condenses before desorption of the silicon compound occurs. This leads to hydrophobization and oleophobization of the solid the silicon compound is absorbed on, but not at all to the desired mass modification. Therefore, in order to obtain the desired easy-to-clean effect in the cured mixture, based on conventional knowledge, all of these processes need to occur and to be completed in the right order and well before the start of the setting of the curable mixture with its related solidification. The skilled person in the art does not expect this to be feasible.

Surprisingly, it was found that the kinetic of all these different processes are just right for the fluoroorganic-substituted compounds of the invention. Even the smallest amount of a fluoroorganic-substituted silicon compound already provides excellent easy-to-clean properties. Furthermore, it was found that the material properties, e.g. the interfacial tension, of the fluoroorganic-substituted silicon compound are different from those of other silicon compounds due to the fluorine substitution. Additionally, the high ionogenicity and alkalinity, as occurring in particular in aqueous curable mixtures on the basis of hydraulic setting binders, have a strong influence on the kinetics of said processes. Thus it was surprising and unexpected to the skilled person in the art that the superior easy-to-clean properties are obtained not only on the surface of the cured mineral-based mortar, but also on the inside of the set mixture.

The invention further pertains to the use of a fluoroorganic-substituted silicon compound which is adsorbed on a solid in a hydraulically curable mixture containing more than 25 to 60 wt.% of hydraulically setting binder, 20 to 74 wt.% of at least one added substance, and 0.001 to 8 wt.% of the fluoroorganic- substituted silicon compound which is adsorbed on a solid, and optionally 0 to 40 wt.% of further adjuvants, based on 100 wt.% of curable, water-free mixture. This mixture in cured form exhibits the desired easy-to-clean properties.

The use of the fluoroorganic-substituted silicon compound which is adsorbed on a solid surprisingly does not show any negative properties. It can be employed in the known formulations without the need to adapt the formulation to any great extent. Hence, e.g. the wettability, the mortar workability, the water demand to obtain the same consistency, and the hydration do not change at all or only marginally in comparison with the formulation without the fluoroorganic- substituted silicon compound.

The cited objective of the present invention can be achieved in a particularly surprising and advantageous manner by homogeneously admixing the fluoroorganic-substituted silicon compound which is already adsorbed on a solid with the dry mixture, e.g. a dry building material composition, or upon mixing water into the dry mixture. By doing so, the permanent easy-to-clean properties can be obtained throughout the manufactured substrate and the building material composition, respectively. Thus, fluoroorganic-substituted silicon compounds adsorbed on a solid and preferably in a free-flowing form can be stored, transported, and handled easily, e.g. for sacking, transporting, weighing, and dosing when making the curable mixture. They can therefore exert their desired effect in the building material composition, preferably in hydraulically setting mixtures, in particular cement-containing mixtures such as concrete and mortars, as homogeneously distributed components in connection with the mixing water and the prevailing alkaline pH-value, in which process hydrolysis of the added fluoroorganic-substituted silicon compound occurs, followed by reaction with the present components of the building material composition. The thus obtained and cured material reveals in advantageous manner the permanent and in particular the homogeneous easy-to-clean properties. The utilization of a fluoroorganic-substituted silicon compound which is adsorbed on a solid in the curable mixture according to the invention, the process to make the same, and its use yields various advantages. Hence, homogeneous mixtures, in particular dry mixtures, and preparations can be manufactured in an easy manner ex factory. When used at the building or construction site, they just have to be mixed with water. The cured mixtures obtained according to this embodiment also impart the advantageous easy-to-clean properties.

The curable mixture according to the invention which comprises the fluoroorganic-substituted silicon compound which is adsorbed on a solid possesses a good wettability and mortar workability when mixed with water. Hence, the hydrophobic and oleophobic properties are revealed only after the mixture has cured. When a monomer compound having alkoxy groups, e.g. fluoroalkoxy silane, is used, the silicon compound is typically in non-hydrolyzed and in monomer form, i.e. not more than about 10%, in particular not more than 5%, of the alkoxy groups of the silicon compound are hydrolyzed. As a result, the reactive groups, in particular the alkoxy groups, survive during the preparation and storage of the fluoroorganic-substituted silicon compound which is adsorbed on a solid, even when mixed with other solid mortar ingredients, as long as no water is added. After the addition of water and mixing therewith, the fluoroorganic-substituted silicon compound is believed to desorb from the solid and the alkoxy groups hydrolyze, in which process due to the subsequent reactions, e.g. condensation, the desired advantageous properties are achieved. The curable mixtures according to the invention are preferably concrete-related mixtures and mortars. The term concrete-related mixture is understood by the skilled person in the art to include dry concrete mixtures, optionally mixed with water, subsequently summarized as concrete. Concrete comprises aggregates with a diameter of 3 mm and larger and up to 64 mm. Mortars comprise aggregates which - in the context of mortars - are also known as fillers, with a diameter of 0.005 to 5 mm, in particular 0.001 to 3 mm. Mortars can be in the form of dry mortars, pasty mortars, and mortars with two or more components. In many cases dry mortars are preferred, in particular when all components, i.e. ingredients, are present in solid form. Hence, the dry mortars can be mixed ex factory and only water needs to be added on the building or construction site before application. Pasty mortars are often preferred when no hydraulically setting binders are present and when completely pre-mixed systems, including the total amount of required water, are desired. Mortars with two and more components include mortars comprising a solid, e.g. a powdery component and one or more liquid and/or high-viscous components. The liquid component typically comprises the liquid ingredients of the formulation.

In the context of the invention, mineral binders comprise a) a hydraulically setting binder, in particular a cement, activated blast furnace slag and/or silico- calcareous fly ash, b) a latent hydraulic binder, such as in particular pozzolane and/or metakaolin, which reacts hydraulically in combination with a calcium source such as calcium hydroxide and/or cement and/or c) a non-hydraulic binder which reacts under the influence of air and water, in particular calcium hydroxide, calcium oxide, quicklime, hydrated lime, magnesia cements, water glass and/or gypsum, by which is meant in this invention in particular calcium sulfate in the form of a- and/or β-semihydrate and/or anhydrite of form I, II and/or III.

Preferred hydraulically setting binder a) are cements, in particular Portland cement, Portland composite cement, blast furnace cement and blast furnace slag cement, pozzolane cement, i.e. cement with a proportion of pozzolane, for instance in accordance with EN 197-1 CEM I, II, III, IV, and V and/or calcium phosphate cement and/or aluminous cement such as high alumina cement, calcium alumina cement, sulfo-alumina cement and/or calcium sulfo-alumina cement. Preferred latent hydraulic binders b) are pozzolane, metakaolin, burnt shale, diatomaceous earth, moler, rice husk ash, air cooled slag, calcium metasilicate and/or volcanic slag, volcanic tuff, trass, fly ash, silica fume, microsilica, blastfurnace slag and/or silica dust.

Preferred non-hydraulic binders c) are gypsum, by which is meant in this invention in particular calcium sulfate in the form of a- and/or β-semihydrate and/or anhydrite of form I, II and/or III, calcium hydroxide, calcium oxide, lime such as quicklime and/or hydrated lime, magnesia cements and/or water glass.

The particularly preferred mineral binder is a hydraulically setting binder, e.g. cement, in particular Portland cement, Portland composite cement, blast furnace cement, calcium alumina cement, calcium sulfo-alumina cement, sulfo-alumina cement, which may contain some (i.e. up to 10% by weight of the binder) latent- hydraulic and/or non-hydraulic binder.

In a preferred embodiment, the curable mixture comprises a mineral binder which itself comprises at least one hydraulically setting binder. When several mineral binders are used, it is as a rule advantageous to employ less than 50 wt.%, in particular less than 30 wt.%, of latent hydraulic binder b) and/or non-hydraulic binder c), based on the sum of added mineral binders. For all embodiments, the curable mixture preferably comprises less than 10 wt.%, in particular less than 5 wt.%, of latent hydraulic binder b) and/or non-hydraulic binder c), based on the sum of added mineral binders.

In addition to the mineral binder, it is possible to add organic binders. They comprise film-forming, water-insoluble polymer binders in the form of an aqueous polymer dispersion or a water-redispersible polymer powder obtained by drying aqueous dispersions. The aqueous polymer dispersions, according to the invention also just named dispersions, are typically obtained by emulsion and/or suspension polymerization. These are well-established technologies known to the skilled person in the art.

In the context of the invention, water-insoluble polymer binders may be vinyl (co)polymers, polyurethanes, poly(meth)acrylates, polyesters, polyethers, as well as mixtures and hybrids thereof. In a preferred embodiment, water- insoluble polymer binders are aqueous polymer dispersions and water- redispersible polymer powders which may be obtained by drying the dispersions. The dispersions are typically obtained by emulsion and/or suspension polymerization and may contain vinyl (co)polymers, polyurethanes, poly(meth)acrylates, polyesters, polyethers, as well as mixtures and hybrids thereof. In a particularly preferred embodiment, the dispersions are based on (co)polymers of ethylenically unsaturated monomers preferably comprising monomers from the group of vinyl acetate, ethylene, acrylate, methacrylate, vinyl chloride, styrene, butadiene and/or C4-C12 vinyl ester monomers.

Such (co)polymers are preferably homo- or copolymerizates on the basis of 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, pure (meth)acrylate, styrene-acrylate and/or styrene- butadiene, wherein the vinyl versatate preferably is a C₄- to C-12-vinyl ester, in particular a C9 -, C10 - and/or a Cn-vinyl ester, and the homo- or copolymerizates can contain about 0 - 50 wt.%, in particular about 0 - 30 wt.%, and quite especially preferably about 0 - 10 wt.% of further monomers, in particular monomers with functional groups.

In a preferred embodiment, the dispersions and the water-red ispersed polymer powders are film-forming at a temperature of 23° C or higher; preferably at 10° C or higher; in particular at 5° C or higher. It is worth mentioning that for aqueous systems the minimum film formation temperature (MFFT) is limited at around 0°C due to freezing of the water. Film-forming means that the (co)polymer is capable of forming a film determined according to DIN 53787.

The binders are stabilized with surfactants and/or water-soluble polymers in a known manner. Aqueous dispersions are typically free of organic solvents. The water-redispersible polymer powders are typically obtained by drying, in particular by spray drying of the aqueous dispersions, which are preferably stabilized with water-soluble polymers. When the water-redispersible polymer powders get into contact with water, they redisperse spontaneously or by at most slight stirring.

In one embodiment, the one or more fluoroorganic-substituted silicon compounds are the only silicon compounds in the curable mixture. In another embodiment, they are used in conjunction with non-fluoroorganic-substituted silicon compounds, e.g. with non-substituted organic silicon compounds, such as aminosilanes or alkoxysilanes, i.e. octyltriethoxysilane. The silicon compounds can be used in any ratio. However, it is noticed that the desired easy-to-clean properties can be obtained only if the fluoroorganic-substituted silicon compound is present in an amount as presented in the claims. Variation of said amount may be desired, depending on the formulation and the specific application. The skilled person in the art is well aware of how to adjust the formulation to achieve an optimized performance.

Fluoroorganic-substituted silicon compounds according the invention may be of various character. In one embodiment (i) they are compounds which are derived from the general formulae (I), (II), (III), (IV) and/or (V). They may contain cross- linkable structural elements which form aliphatic, cyclic and/or crosslinked structures. In a preferred embodiment, at least one structure corresponds in idealized form to the general formula (I)

(HO)[(HO)i_-x(R²)_xSi(A)0]a[Si(B)(R³)_y(OH)_1-yO]b[Si(C)(R⁵)_u(OH)_1-uO]c - [Si(D)(OH)0]_dH (HX)e (I) wherein in formula (I) the structural elements are derived from alkoxy silanes of the general formulae (II), (III), (IV) and/or (V) and - A in formula (I) corresponds in the structural element to an amino residue H₂N(CH2)f(NH)g(CH₂)h(NH)_m(R⁷)n- and is derived from the general formula (II)

H₂N(CH₂)_f(NH)_g(CH₂)_h(NH)_m(R⁷)nS i(OR¹ )₃-x(R²)x (II), wherein f is an integer between 0 and 6, g=0 if f=0 and g=1 if f>0, h is an integer between 0 and 6, x=0 or 1 , m=0 or 1 and n=0 or 1 , with n+m=0 or 2 in formula (II), and R⁷ is a linear, branched or cyclic divalent alkyl group with 1 to 16 C- atoms, - B in formula (I) relates in the structural element to a fluoroalkyl residue R -Y- (CH₂)_k- derived from the general formula (III)

R -Y-(CH₂)_kSi(R³)_y(OR¹ )₃-y (III), wherein R⁴ is a mono-, oligo- or perfluorinated alkyl group with 1 to 9 C-atoms or a mono-, oligo- or perfluorinated aryl group, Y is a CH₂-, O- or S-group, R³ is a linear, branched or cyclic alkyl group with 1 to 8 C-atoms or an aryl group, k=0, 1 or 2 and y=0 or 1 , preferably R⁴ = F₃C(CF₂)_r-, with r=0 to 18, preferably r=5, with Y being a CH₂- or O-group, and preferably is k=1 with Y = -CH₂-,

- C in formula (I) relates in the structural element to an alkyl residue R⁵-, derived from the general formula (IV)

R⁶-Si(R⁵)u(OR¹ )₃-u (IV), wherein R⁵ is a linear or branched alkyl group with 1 to 4 C-atoms, in particular methyl, and u=0 or 1 in formula (IV),

- D in formula (I) relates in the structural element to an alkyl residue R⁵-, derived from the general formula (V)

R⁶-Si(OR¹)₃ (V), wherein R⁶ of the aforesaid formula is a linear, branched or cyclic alkyl group with 1 to 8 C-atoms, and

R¹ in the formulae (II), (III), (IV), (V) and/or (VI) independently is a linear, branched or cyclic alkyl group with 1 to 8 C-atoms or an aryl group, preferably R¹ independently is methyl, ethyl or propyl; with R², R³ and/or R⁵ in the aforementioned formula independently representing a linear or branched alkyl residue with 1 to 4 C-atoms, preferably methyl or ethyl, and

- in formula (I) HX represents an acid, wherein X is an inorganic or organic acid residue, with x, y, and u independent from one another being equal to 0 or 1 and a, b, c, d, and e are independent from one another and an integer with a>0, b>0, c>0, d>0, e>0, and (a+b+c+d) >2, preferably (a+b+c+d) >4, in particular (a+b+c+d) >10, with X comprising e.g. chloride, nitrate, formate or acetate.

In another embodiment (ii) the fluoroorganic-substituted silicon compounds according to the invention are organosiloxane co-condensates or block co- condensates or mixtures thereof, derived from at least two of the aforementioned alkoxy silanes of general formulae (II), (III), (IV), and (V), preferably of formulae (II) and (III) with a molar ratio of 1 :< 3.5 or with a, b, c, and d of the alkoxy silane of formulae (II), (III), (IV), and (V) with a molar ratio of 0.1 < [a/b+c+d], in particular 0,25 < [a/b+c+d] < 6000, and preferably 1 < [a/b+c+d] < 3 with a > 0, b > 0, c > 0, and d > 0. In yet another embodiment (iii) the fluoroorganic-substituted silicon compounds are in monomeric form of the general formula (VI)

R -Y-(CH₂)_kSi(R³)_y(OR¹)₃-y (VI), wherein R⁴, Y, R¹ , R³, k, and y have the meaning as stated above. In addition to this, they may be mixtures of two or more monomeric compounds of the general formula (VI).

In a preferred embodiment, the curable mixture according to the invention comprises as fluoroorganic-substituted silicon compound a fluoroalkylalkoxy- silane of the formula (VII)

F₃C(CF₂)_x(C₂H₄)_ySi(CH₃)_z(OR)3_-z (VII) wherein each R is selected independently from the group consisting of methyl, ethyl, n-propyl, and i-propyl with x being an integer with a value of 0 to 16, y = 0 or 1 , and z = 0 or 1 , preferably y = 1 , and in particular y = 1 , z = 0 and x = 3, 4, 5, 6, 7, 8 or 10.

Preferred, but non-limiting examples of fluoroalkylalkoxysilane of formula (VII) are tridecafluor-1 , 1 ,2,2-tetrahydrooctyl-triethoxysilane and/or tridecafluor-1 , 1 ,2,2- tetrahydrooctyl-trimethoxysilane.

The fluoroorganic-substituted silicon compounds which are used according the invention are preferably selected from the group of fluoroorganic-substituted silanes and fluoroorganic-substituted siloxanes or mixtures thereof. They are preferably selected from the group of fluoroalkyl-substituted monomeric silanes and fluoroalkyl-substituted siloxanes or mixtures thereof. An example of a fluoroalkyl-substituted monomeric silane is 3,3,4,4,5,5,6,6,7,7,8,8,8-trideca- fluorooctyl-triethoxysilane.

Although a large number of different fluoroorganyl-substituted silicon compounds can be used, it is often preferred when the fluoroorganyl-substituted silicon compound does not contain a Si-H bond.

The fluoroorganic-substituted silicon compounds which are adsorbed on a solid can be extracted from the solid with a suitable solvent, e.g. methylene chloride. The obtained liquid extract can be analyzed by GC/MS and/or by NMR. For NMR investigations ²⁹Si- and ¹⁹F-NMR in particular are useful. Where appropriate, also ¹H- and/or ¹³C-NMR spectroscopy may be used. These methods are known to the skilled person. If the fluoroorganic-substituted silicon compound is located in the cured mixture, it can be analyzed according to the process disclosed in EP 0 741 293 A2.

In a preferred embodiment, the fluoroorganic-substituted silicon compound is selected from the group of fluoroorganic-substituted silanes and fluoroorganic- substituted siloxanes, in particular fluoroalkyl-substituted monosilanes and monosiloxanes, and mixtures thereof. The term mixture is understood to include mixtures of fluoroorganic-substituted silicon compounds with other non-fluorine substituted silicon compounds, in particular mixtures of fluoroorganic-substituted silicon compounds of formula (VII) and CrC ₆-alkylalkoxysilanes with alkoxy groups being methoxy, ethoxy, and propoxy groups and as alkyl groups methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and hexadecyl groups are particularly preferred. When mixtures with non-fluorine substituted silicon compounds are introduced, the amount of fluoroorganic-substituted silicon compounds is preferably at least 25 wt.%, in particular at least 50 wt.%, and most preferably at least 75 wt.%, based on the total amount of silicon compound present. The solid, i.e. carrier, on which the fluoroorganyl-substituted silicon compound is adsorbed typically is an inorganic or organic carrier. Preferably, the carrier is free-flowing, can be dosed easily, stored over several months, and wets nicely upon contact with water. It was surprisingly found that these properties do not change at all, or at least not significantly, when adsorbing the fluoroorganyl- substituted silicon compound onto the carrier, i.e. solid. Furthermore, the fluoroorganic-substituted silicon compound which is adsorbed on a solid can be easily mixed with the mineral binder.

It is noted that EP-A-0 919 526 discloses building material compositions comprising a hydrophobic powder containing silicic acid as carrier and hydrophobic components that are liquid at 10°C. The hydrophobic components contain an organosilicon compound, solvent and/or water and emulsifier, with the powder containing 5-80 wt.% of organosilicon compound. The latter is preferably selected from specific alkylalkoxysilanes, organosilanes, and alkalisiliconates. The alkylalkoxysilanes may also be substituted with a halogen, with unsubstituted alkylalkoxysilanes being preferred. It is neither disclosed nor suggested that said mixture may be used for easy-to-clean applications.

In the context of this invention, the solid, i.e. the carrier or carrier material, on which the fluoroorganic-substituted silicon compound is adsorbed is preferably in the form of a powder or granule. According to the invention, the term powder includes granules. Organic carriers are preferably water-soluble polymers and inorganic carriers are an inert inorganic material, i.e. not a mineral binder.

In the context of this invention, the solid, i.e. the carrier comprising the adsorbed fluoroorganic-substituted silicon compound, possesses free-flowing properties and thus it can easily be transported and mixed into mixtures of different composition. The free-flowing properties in most cases can easily be determined optically by pouring the powder from e.g. a container onto a flat surface. However, for more critical cases, or if an exact rating is required, it can be determined in accordance with ISO 4342 by using the pourability tester according to Dr. Pfrengle (sold e.g. by Karg-lndustrietechnik). In that case, a given amount of powder is poured through a defined orifice onto a slightly roughened surface. By measuring the height of the obtained cone formed by the powder, the pouring angle can be determined according to a reference list. The lower the pouring angle, expressed in degrees, the better the pourability and the free-flowing characteristics of the powder. Hence, the inventive free-flowing powder has typically a pouring angle of about 70° or less, preferably of about 60° or less, and in particular of about 50° or less.

In an embodiment of the invention, the carrier, on which the one or more fluoroorganic-substituted silicon compounds are absorbed, is an organic material. Preferably, it is an organic polymer. More preferably, it is selected from one or more water-soluble polymers. Even more preferably, the carrier is at least one synthetic polymer and/or at least one biopolymer such as polysaccharides, peptides and/or proteins, which may have been prepared naturally and/or synthetically. The water-soluble polymer may optionally be synthetically modified. These polymers, provided they are not dissolved or dispersed, are solids at room temperature and preferably higher molecular compounds. When several water-soluble polymers are used, use can also be made of a combination of one or more natural compounds with one or more synthetically prepared compounds. The water-soluble polymers typically have a bulk density of about 200 g/l or higher, in particular of about 400 g/l and higher. Hollow particles are less preferred.

Biopolymers and their derivatives preferably usable as carrier are e.g. cold water-soluble polysaccharides and polysaccharide ethers, such as for instance cellulose ethers, starch ethers (amylose and/or amylopectin and/or their derivatives), guar ethers, dextrins and/or alginates. Also synthetic polysaccharides such as anionic, nonionic or cationic heteropolysaccharides can be used, in particular xanthan gum, welan gum and/or diutan gum. The polysaccharides can be, but do not have to be, chemically modified, for instance with carboxym ethyl, carboxyethyl, hydroxyethyl, hydroxypropyl, methyl, ethyl, propyl, sulfate, phosphate and/or long-chain alkyl groups. Preferred usable peptides and/or proteins are for instance gelatine, casein and/or soy protein. Quite especially preferred biopolymers are dextrins, starches, starch ethers, casein, soy protein, gelatine, hydroxyalkyl-cellulose and/or alkyl-hydroxyalkyl- cellulose, wherein the alkyl group may be the same or different and preferably is a C-i - to C6-group, in particular a methyl, ethyl, n-propyl- and/or i-propyl group.

Synthetic, water-soluble organic polymers preferred as carrier can consist of one or several polymers, for instance one or more polyvinyl pyrrolidones and/or polyvinyl acetals with a molecular weight of 2,000 to 400,000, fully or partially saponified polyvinyl alcohols and their derivatives, which can be modified for instance with amino groups, carboxylic acid groups and/or alkyl groups, with a degree of hydrolysis of preferably about 70 to 100 mol.%, in particular of about 80 to 98 mol.%, and a Hoppler viscosity in 4% aqueous solution of preferably 1 to 100 mPas, in particular of about 3 to 50 mPas (measured at 20°C in accordance with DIN 53015), as well as polymerizates of propylene oxide and/or ethylene oxide, including their copolymerizates and block copolymerizates, styrene-maleic acid and/or vinyl ether-maleic acid copolymerizates. Quite especially preferred are synthetic organic polymers, in particular partially saponified, optionally modified, polyvinyl alcohols with a degree of hydrolysis of 80 to 98 mol.% and a Hoppler viscosity as 4% aqueous solution of 1 to 50 mPas and/or polyvinyl pyrrolidone.

In another embodiment an inorganic carrier is used. Inorganic carriers are preferably inert inorganic carriers. In the context of this invention, inert means that this material does not undergo any reaction with water under ambient conditions, i.e. at 23°C and at a pH-range of 4 to 8. By reaction is also meant that the powder does not swell upon contact with water and/or alkaline cement water. Hence, the inert inorganic carrier, if taken alone, would be classified as filler and/or an aggregate and typically does not provide any additional functionality such as water retention, hydrophobicity, defoaming, etc. Thus, on the inorganic carrier there is no cement and/or hydrated cement.

Non-limiting examples of inert inorganic carriers are alumosilicate, silicon oxide, silicon dioxide, aluminium silicon oxide, calcium silicate hydrate, aluminium silicate, magnesium silicate, magnesium silicate hydrate, magnesium aluminium silicate hydrate, mixtures of silicic acid anhydrite and kaolinite, aluminium silicate hydrate, calcium aluminium silicate, calcium silicate hydrate, aluminium iron magnesium silicate, calcium carbonate, calcium magnesium carbonate, calcium metasilicate. anticaking agents, particulate titanium dioxide, expanded perlite, cellite, cabosil, circosil, aerosil, eurocell, fillite, promaxon, china clay, dolomite, limestone powder, chalks, layered silicates and/or precipitated silicas. Preferred are silicate, silica, silica fume, fumed silica, precipitated silicas, carbonates, kaolin and/or china clay and most preferred are silicate, silica and/or fumed silica. Less preferred are zeolites.

The physical form of the inorganic carrier can be e.g. a spherical, platelet, rod and/or lamellae-like structure, with spherical forms often being preferred. However, it is helpful if the inorganic carrier shows a good pourability in order to allow good processing of the material. Most typically, the fluoroorganic- substituted silicon compound adsorbed on the solid, i.e. carrier, shows the same or a similar pourability as the carrier alone.

The mean diameter of the inorganic carrier in powder form, measured e.g. by light scattering such as e.g. ISO 13320-1 , typically is less than about 1 ,000 pm and preferably less than about 500 pm, in particular about 200 pm or less, and most preferably about 100 pm or less. It can be as low as e.g. 1 pm or lower, but in generally, due to the toxicity of the respiration of small dust particles and for handling reasons, it is preferred that the mean diameter of the inorganic carrier is at least about 5 m or higher, preferably about 10 m or higher, and in particular about 20 m or higher. If the carrier is in the form of aggregates, the said mean diameter refer to the agglomerates. Basically each inert inorganic carrier in powder form can be used as carrier, irrespective of its BET-surface, measured according to ISO 5794-1 , Annex D. However, the loading of the mixture is lower when the BET surface of the carrier is lower. Thus, the BET surface can be as low as e.g. 5 m²/g or lower, or as high as e.g. 500 m²/g or higher. Often it is an advantage, however, to have powders with high amounts of adsorbed fluororganyl-substituted silicon compound. Therefore, it is typically preferred to have inorganic carriers with a BET-surface of at least 20 m²/g, in particular of at least 50 m²/g, more preferably of at least 100 m²/g, and in particular of at least 250 m²/g. In yet another embodiment the carrier is a mixture of the above-mentioned organic and inorganic carriers.

The particle size of the solid, e.g. carrier, can be adjusted e.g. by milling using e.g. a ball mill. Alternatively, the particle size can be increased by suitable agglomeration processes. These processes can be carried out before, during or after the fluoroorganic-substituted silicon compound is adsorbed on the solid. The skilled person is aware of these processes and suitable equipment.

The content of the fluoroorganic-substituted silicon compound which is adsorbed on the solid, i.e. carrier, may be as low as e.g. 2.5 wt.% and as high as e.g. 75 wt.%, based on the sum of the fluoroorganic-substituted silicon compound and the solid. In a preferred embodiment, it is between 10 wt.% and 70 wt.%, in particular between 20 wt.% and 65 wt.%.

The powder according to the invention is preferably obtained by adsorbing the fluoroorganic-substituted silicon compound onto the carrier. In one preferred embodiment, the fluororganyl-substituted silicon compound is adsorbed as such, i.e. as mere liquid. When organic carriers are used, this method is particularly preferred. In a preferred embodiment, the fluoroorganic-substituted silicon compound absorbed on the carrier is then used as such without a further processing step.

In another embodiment the fluoroorganic-substituted silicon compound is first emulsified in water using at least one surfactant and/or water-soluble polymer, also known under the term protective colloid. A wide selection of surfactants can be used, e.g. non-ionic, anionic, cationic or amphoteric surfactants. The skilled person in the art knows well the types of surfactants which best suit the specific application. However, in many cases non-ionic surfactants are preferred. Water-soluble polymers may be selected from the ones which are suitable as carrier. This method can be used to adsorb the fluoroorganic-substituted silicon compound onto an inorganic carrier. This results in a system which can be classified as a combined organic and inorganic carrier. The skilled person is well aware of suitable techniques and procedures to adsorb liquids onto carriers.

Generally, it is preferred not to use organic solvents to adsorb the fluoroorganic- substituted silicon compound onto the carrier, although it might be helpful in selected cases. The skilled person is well aware of suitable solvents. In another embodiment it is possible to coat the solid, i.e. carrier, after the one or more fluoroorganic-substituted silicon compounds have been adsorbed, the carrier thus comprising the adsorbed fluoroorganic-substituted silicon compound with e.g. water-soluble polymers. This allows for additional protection of the fluoroorganic-substituted silicon compound and may be advantageously used when a retarded desorption of the fluoroorganic-substituted silicon compound is preferred. The skilled person is well aware of such coating techniques and procedures.

These processes are suitable for all types of carriers, with it being particularly preferred when inorganic carriers as well as water-soluble polymeric carriers are used. The types of mixers used for this process are well known to the person skilled in the art. Preferred mixers are powder mixers equipped with nozzles to spray the liquid mixture onto the carrier. Non-limiting examples are e.g. ploughshare mixers and/or granulators. The process can be carried out as a batch, semi-continuous or continuous process. The preferred temperature to carry out this process is typically room temperature or slightly above. However, the temperature of the mixture might need to be adjusted to obtain the ideal viscosity for spraying it into the mixing chamber, followed by adsorption onto the carrier.

The obtained powder can be further mixed with additives, which are preferably in the form of solids, particularly in the form of a free-flowing and/or pourable powder. In a preferred embodiment, the fluoroorganic-substituted silicon compound, e.g. the fluoroalkylalkoxysilane, utilized according to the invention, is present basically in non-hydrolyzed form. The hydrolysis of the fluoroorganic-substituted silicon compound occurs upon the use according to the invention, preferably at alkaline pH-value, e.g. after admixing water to a cementitious curable mixture according to the invention and/or upon using a suitable catalyst, e.g. a suitable transition metal catalyst, well known to the skilled person in the art.

The curable mixture according to the invention comprising a mineral binder and a fluoroorganic-substituted silicon compound which is adsorbed on a solid may contain further added substances. According to the invention, they include aggregates, fillers, adjuvants, as well as additives.

Suitable added substances include aggregates, fillers, inorganic and organic acids and bases, buffer substances, fungicides, bactericides, algicides, biocides and microbiocides, odourants, corrosion inhibitors such as alkylammonium benzoates, aminoalcohols, glycolic acid and/or its alkali and earth alkali salts, preservatives, hydrophobic agents such as fatty acids and their salts and esters, fatty alcohols, silanes, air entraining agents, wetting agents, defoamers or anti- foaming agents, surfactants, film-forming agents, agents to control cement hydration such as setting and solidification accelerators, setting and solidification retarders, thickeners, dispersing agents, rheology adjuvants such as cement superplasticizers, polycarboxylates, polycarboxylate ether, polyacrylamide and/or thickener, water retention agents, polysaccharide ethers, cellulose fibres and cellulose ether, starch ether, guar ether, water-redispersible polymer powder, agents to reduce efflorescence, bleeding, sedimentation and/or shrinkage, pigments, adjuvants for the reduction of powder caking, hydrolysis and/or condensation catalysts and/or agents for setting the pH-value.

Such catalysts catalyze the hydrolysis of Si-OR' bonds to form Si-OH groups and/or catalyze the condensation of Si-OH groups to form Si-O-Si bonds. Alternatively or in addition, if a catalyst is required, it can be added separately to the curable mixture.

Most typically, the catalyst is a base, an acid, an amine, a fluoride salt, a metal salt, a metal complex, an organometallic and/or a metal-organic compound, the metal being preferably a transition metal and/or in the form of a powder, granulate and/or flake. If the catalyst is a liquid, it is generally advantageous when it is transformed into a solid form by means of e.g. granulation, drying, adsorption and/or encapsulation.

The addition of a catalyst may be particularly useful when the mineral binder of the curable mixture is a non-hydraulic binder.

Suitable aggregates or fillers are quarzitic and/or carbonate sands and/or flour such as quartz sand and/or limestone flour, carbonates, silicates, layered silicates, precipitated silica, lightweight fillers such as hollow microspheres made of glass or polymers, e.g. polystyrene spheres, alumino silicates, silica, aluminium silica, calcium silicate hydrate, silica, aluminium silicate, magnesium silicate, aluminium silicate hydrate, calcium aluminium silicate, calcium silicate hydrate, aluminium iron magnesium silicate, calcium metasilicate and/or volcanic ash, microsilica, fly ash, zeolites, kaolin, mica, talcum, wollastonite or clay and/or mixtures thereof.

In a preferred embodiment, aggregates comprise aggregates according to EN 206-1 :2000, in particular sands, gravel, split, porphyry, quartz flour, limestone flour, stone flour and mixtures thereof. If the curable mixture according to the invention is a concrete, it preferably comprises aggregates with a maximum diameter of 8 to 64 mm, in particular of 8 mm, 16 mm, 32 mm or 64 mm, according to DIN 1045-2. If the curable mixture according to the invention is a mortar, it preferably comprises aggregates with a maximum diameter of 2 to 5 mm, in particular of 2, 3, 4 or 5 mm.

The curable mixture according to the invention preferably contains a) more than 25 to 60 wt.%, preferably 26 to 45 wt.%, of at least one mineral binder, preferably hydraulic binder, in particular cement, b) 20 to 74 wt.%, preferably 30 to 74 wt.%, of at least one added substance, c) 0.001 to 8 wt.%, preferably 0.003 to 5 wt.%, in particular 0.005 to 4 wt.%, more preferably 0.01 to 3 wt.%, most preferably 0.05 to 2 wt.%, of at least one fluoroorganic-substituted silicon compound which is adsorbed on a solid and optionally d) 0 to 40 wt.% of further adjuvants, based on 100 wt.% of curable, water-free mixture. Additionally, the fluoroorganic-substituted silicon compound which is adsorbed on a solid, is preferably used in these curable mixtures.

Most typically, water is added to the curable mixture according to the invention and to the curable mixture obtained by the processes according to the invention for allowing the mixture to cure. Hence, the process to prepare a cured mixture comprises the step of mixing the curable mixture. The amount of water amounts e.g. 1 to 120 wt.% water, based on 100 wt.% of curable mixture free of water. More preferably, concrete requires about 1 to 20 wt.%, preferably 2 to 18 wt.%, of water and mortars demand about 15 to 100 wt.%, in particular 17 to 60 wt.% of water, based on 100 wt.% of curable, water-free mixture.

Preferably the curable mixture, in any embodiment according to the invention, but more preferably for concrete and mortars, comprises more than 26 wt.% of one or more mineral binders, preferably more than 27 wt% of one or more mineral binders.

The mixture for concrete consists preferably of

a-i ) >25 to 40 wt.%, preferably >25 to 30 wt.%, of at least one hydraulic binder, in particular cement,

b-i ) 30 to 74 wt.%, preferably 50 to 74 wt.%, of at least one aggregate,

c-i ) 0.001 to 8 wt.%, preferably 0.003 to 5 wt.%, in particular 0.005 to 4 wt.%, more preferably 0.01 to 3 wt.%, most preferably 0.05 to 2 wt.%, of at least one fluoroorganic-substituted silicon compound which is adsorbed on a solid, and

optionally 0 to 40 wt.% of further adjuvants and additives, wherein the added components add up to the sum of 100 wt.%.

Preferred adjuvants and additives for concrete mixtures are in particular cement superplasticizers in amounts of 0.01 to 2 wt.%, in particular 0.05 to 0.5 wt.%, and further adjuvants in amounts of 0.01 to 10 wt.%, preferably 0.01 to 3 wt.%, in particular 0.01 to 1 wt.%, based on 100 wt.% curable, water-free mixture, wherein all added components add up to the sum of 100 wt.%, based on the water-free mixture.

Non-limiting examples of cement superplasticizers are all common dispersing agents, in particular polycarboxylate ether (PCE's), polymethacrylic acid, lignin sulfonate, melamine formaldehyde sulfonate and/or naphthaline formaldehyde sulfonate. If so desired, one or more superplasticizers can also be used as the one or more polymers that serve as a carrier for the fluoroorganic-substituted silicon compound. Non-limiting examples of further adjuvants are wetting agents such as siliconates or alkylphosphonates, defoamer such as trialkylphosphate, air entraining agents, retarders and accelerators to adjust the hydration and curing of the mixture.

In a preferred embodiment is the mixture a mortar, in particular a dry mortar of a two-component mortar. The composition of such mortars depends on the type of mineral binder and on the type of application the mortar is optimized for. The skilled person is well aware of the specifics.

The mixture for a hydraulically setting mortar, in particular for a dry mortar, consists preferably of

a₂) >25 to 60 wt.%, preferably 26 to 45 wt.%, of at least one hydraulic binder, in particular cement,

b₂) 20 to 74 wt.%, preferably 30 to 74 wt.%, of at least one aggregate or filler, c₂) 0.001 to 8 wt.%, preferably 0.003 to 5 wt.%, in particular 0.005 to 4 wt.%, more preferably 0.01 to 3 wt.%, most preferably 0.05 to 2 wt.%, of at least one fluoroorganic-substituted silicon compound which is adsorbed on a solid, and

optionally 0 to 40 wt.% of further adjuvants and additives, wherein the added components add up to the sum of 100 wt.%, based on the water-free mixture.

Beyond that a curable mixture according to the invention, which is formulated as a mortar, in particular as a dry mortar, may contain as further components additionally 0.001 to 3 wt.% of cellulose ether and/or cellulose fibers, 0.1 to 30 wt.% of a water-redispersible polymer powder and 0 to 10 wt.% of further adjuvants, wherein the added components add up to the sum of 100 wt.%, based on the water-free mixture.

The curable mixture according to the invention and the curable mixture prepared according to the processes of the invention can preferably be formulated and then used as tile grout, repair mortar, powder paint, adhesive putty, renders, plaster, in particular top coat, as well as gypsum and/or lime and/or cement plaster, levelling mortar, trowelling compound, industrial flooring mass, bonding mortar, sealing compound, thermal insulation mortar, ceramic tile adhesive, primer, concrete paving tiles and/or as cement-based masses for crude oil, natural gas and/or geothermal heat boreholes, in order to obtain hydrophobic and oleophobic properties in the cured mixture.

These mortars according to the invention can, when mixed with water, be applied onto all known surfaces. Preferred, non-limiting examples of surfaces are concrete, bricks, wood, renders, plasters, skim coats, screeds, levelling compounds such as self-levelling floor screeds, crack fillers, putty, gypsum plaster boards, cement fiber boards, dry building elements and/or tiles, in particular the margins and/or edges of tiles for grouts, in particular tile grouts. Alternatively, they can be processed into precast forms.

In one embodiment, the curable mixture according to the invention is applied as hydraulically setting mixture in the concrete industry to manufacture e.g. precast concrete, whereby known pug mill mixers can be used.

In doing so, cement and other solid aggregates are preferably premixed. Liquid, non-aqueous components may be also added in small amounts. However, aqueous formulations are premixed preferably with the mixing water or mixed in after the addition of the mixing water. Powdery formulations may be dispersed into the mixing water or added to the dry premix. The amount of the added water can be adjusted to obtain the desired w/c-value. Alternatively, water is added first to the mixing device and the solid compounds comprising the mineral binder and the fluoroorganic-substituted silicon compound, which is adsorbed on a solid, are mixed into the water either as individual compounds or as solid premix. It is noted that for producers of cement-based products such as concrete based materials and mortars, it was of great interest to modify these products in such a manner that the desired easy-to-clean properties are permanent and independent of abrasion, cracks and weather. This is now possible in an easy manner with the curable mixture according to the invention. Hence, the costs for cleaning and maintenance can be reduced significantly by prolonged cleaning cycles.

The invention is further elucidated with reference to the following examples. Unless indicated otherwise, the experiments were carried out at a temperature of 23°C and a relative humidity (RH) of 50%.

Example 1 : Preparation of powder P1

In a commercially available household kitchen machine were placed 50 g of Sipernat® 22 (a chemically obtained silica from Evonik Industries having a BET surface of 190 m²/g, measured following ISO 5794-1 , Annex D, and a mean particle size d50 of 1 10 pm, measured by laser diffraction following ISO 13320- 1 ) and 50 g of 3,3,4,4,5,5,6,6,7, 7, 8,8,8-tridecafluoroctyl triethoxy silane (Dynasylan® F 8261 from Evonik Degussa) were added dropwise while stirring vigorously. A homogeneous free-flowing powder was obtained having about the same pouring angle according to ISO 4342 as the carrier (Sipernat 22) itself, which is well below about 50°.

Example 2 (Reference): Preparation of powder VP-1

The procedure of Example 1 was repeated, but as silicon compound was used octyltriethoxy silane (from Evonik Degussa) used. A homogeneous free-flowing powder was obtained having about the same pouring angle according to ISO 4342 as the carrier itself, which is well below about 50°.

Example 3: Preparation of joint filler dry mortar master batch MB-1

5 kg of a dry mix formulation MB-1 , consisting of 37.5 parts by weight of a Dyckerhoff Weisszement 52, 5N (which is an ordinary Portland cement CEM I 52.5), 1 parts by weight of a high alumina cement (Ternal® W), 48.5 parts by weight of a natural calcium carbonate having a mean particle size of 45 pm (Durcal® 65), 8.0 parts by weight of a magnesium silicate hydrate (Luzenac® H-100), 3.0 parts by weight of a metakaolin (Metastar® 501 ), 1 .0 part by weight of a titanium dioxide (Kronos® 2190), and 1 .0 part by weight of a film-forming, water-redispersible polymer powder on the basis of a water-insoluble ethylene/vinyl acetate copolymer (Elotex® MP2100) were prepared by mixing the components in a 1 0 I vessel with a FESTO stirrer until a homogeneous dry mortar master batch was obtained.

Example 4: Hydrophobicity Test The dry mortar master batch MB-1 was mixed with the powders P1 and VP1 from Examples 1 and 2. The amount of powder added, which is indicated in Tables 1 and 2, sums up with the used dry mortar master batch MB-1 to a total of 100 parts by weight of dry mixture. 200 g of the obtained dry mixture were added slowly to 60 g of water while stirring. This mixture was stirred afterwards for one minute with a 60 mm propeller stirrer with a speed of 800 rpm. After a maturing time of 3 minutes, the mortar was again stirred by hand for 15 seconds. By using a template with an opening of 12 cm x 5 cm and a thickness of 3 mm, specimens were prepared on a cement fibre board having a water uptake of not more than 20 wt.%. After a curing time of 24 hrs at standard conditions (23°C/50% RH), one portion of the mortar surface was sanded using a corundom stone (1 mm depth). On both parts of the specimen (untreated and sanded surfaces) a water drop was placed and the time recorded, until the drop was soaked up completely. It is noted that in all Examples the mortar showed a good wettability and the water could be worked in without any problems.

Table 1 The time was recorded in minutes, until a water drop (ca. 0.2 ml) was fully absorbed by the mortar having cured for 24 hrs.

a) The amount of powder added, recorded in wt.%, sums up with the used dry mortar master batch MB-1 to a total of 100 parts by weight of dry mixture.

The sanded mortar surface of reference Exp. No. 1 .1 (without any added power) soaks up the water drop immediately, while the untreated mortar surface is only very slightly more water-repellent. However, upon addition of a powder comprising an adsorbed alkoxy silane (powders P1 and VP1 , respectively), the untreated as well as the sanded mortar surfaces become hydrophobic, even at low powder contents. At higher powder amounts (2.0 wt.%) only minor differences were observed. However, at lower powder amounts (0.5 wt.%, which reflects an amount of silicon compound of 0.25 wt.%), Exp. No. 1 .2, which is according to the invention, exhibits a distinctly higher hydrophobicity of the sanded surface in comparison to reference Exp. No. 1 .3. Hence, the use of small amounts of fluoroorganic-substituted silicon compound improves the mass- hydrophobization of cured mortars significantly.

It is noted that Exp. Nos. 1 .2 to 1 .5 revealed a good hydrophobicity, i.e. having a contact angle of the water on the untreated as well as on the sanded mortar surface of well above 90°.

Example 5: Oleophobicity Test The procedure of Example 4 was repeated, except that instead of a water drop a drop of olive oil was placed on the untreated and the sanded mortar surfaces.

Table 2: The time was recorded in minutes, until a drop of olive oil (about 0.2 ml) was fully absorbed by the mortar having cured for 24 hrs.

b) Even 7 days after its addition to the mortar surface the oil drop is present and shows no signs of adsorption (no wetting at all).

Reference Exp. No. 2.1 (without any added power) soaks up the olive oil drop within a very short time, exhibiting no oleophobic character. The untreated mortar surface of reference Exp. Nos. 2.3 and 2.5, which contain a non-fluorinated organosilicon compound, possess a good oleophobic character, in particular at higher loadings (e.g. 2.0 wt.% of powder VP1 ). However, as soon as the surface is damaged (which is simulated with the sanded surface), the capability to repel olive oil is drastically reduced and no oleophobic properties can be observed anymore. Hence, only the surface has limited oleophobic properties, but not the whole mass is oleophobized. Comparing the untreated surfaces data of Exp. No. 2.2 with those of Exp. No. 2.3 (Ref) reveals that using a fluoroorganic-substituted silicon compound is clearly more effective in oleophobization than using the non- fluorinated silicon compound. Therefore, a lower amount can be used to obtain the same degree of oleophobization. And this effect becomes even more distinct on the scratched surface.

With respect to the oleophobization of the mass of the mortar, only Exp. Nos. 2.2 and 2.4, which contain a fluoroorganic-substituted silicon compound and which are according to the invention, provide the desired properties. Therefore, also damaged surfaces repel olive oil and thus provide the protection required. What is more, in Exp. No. 2.4 it was surprising to see that the drop of olive oil is repelled completely and no wetting is observed at all. As a matter of fact, due to the strong oleophobicity of the untreated as well as the sanded mortar surface, the olive oil drop could be moved around like a billiard ball - even after a period of 7 days!

It is further noted that Exp. Nos. 2.2 and 2.4 revealed a good oleophobicity, i.e. having a contact angle of the olive oil on the untreated as well as the sanded mortar surface of well above 90°. Additionally, the cured mortars- despite the excellent hydrophobic and oleophobic character - exhibited a good adhesion to the substrate, excellent compressive strengths, as well as a good cohesion. Furthermore, the mortar mixed with water set within the normal time, i.e. no significant changes in mortar hydration were observed. Thus, the cured mixture according to the invention provides excellent hydrophobic and oleophobic - i.e. easy-to-clean - properties not only on the surface, but all through the whole mass.

Claims

1 . Curable mixture comprising

- more than 25 wt.% of one or more mineral binders, based on the total amount of the curable mixture,

- 0.001 to 8 wt.% of one or more fluoroorganic-substituted silicon compounds, which are adsorbed on a solid, based on the total amount of the curable mixture, and

- optionally further added substances.

2. Mixture of claim 1 , wherein the mineral binder comprises at least one hydraulically setting binder.

3. Mixture of claim 1 or 2, wherein the fluoroorganyl-substituted silicon compounds are selected from the group of fluoroorganic-substituted silanes and fluoroorganic-substituted siloxanes and mixtures thereof, in particular selected from the group of fluoralkyl-substituted monosilanes,fluoralkyl- substituted monosiloxanes and mixtures thereof.

4. Mixture of any one of claims 1 to 3, wherein the fluoroorganyl-substituted silicon compound does not contain a Si-H bond.

5. Mixture of any one of claims 1 to 4, wherein the fluoroorganyl-substituted silicon compound is a fluoroalkylalkoxysilane of the formula

F₃C(CF₂)_x(C2H4)_ySi(CH₃)z(OR)3-z wherein each R is selected independently from the group consisting of methyl, ethyl, n-propyl, and i-propyl, x is an integer with a value of 0 to 16, y = 0 or 1 , and z = 0 or 1 , preferably y = 1 , and in particular y = 1 , z = 0, and x = 3, 4, 5, 6, 7, 8 or 10.

6. Mixture of any one of claims 1 to 5, wherein the proportion of fluoroorganic- substituted silicon compound which is adsorbed on the solid is 2.5 to 75 wt.%, based on the sum of the fluoroorganic-substituted silicon compound and the solid.

7. Mixture of any one of claims 1 to 6, wherein the solid on which the fluoroorganic-substituted silicon compound is adsorbed comprises an inorganic carrier, wherein the inorganic carrier preferably has a BET-surface of at least 20 m²/g.

8. Mixture of any one of claims 1 to 7, containing at least one added substance from the group of aggregates, fillers, polysaccharide ethers, cellulose ethers, water-redispersible polymer powders, cellulose fibres, cement superplasticizers, thickeners, anti-foam ing agents, air-entraining agents, wetting agents, water retention agents, agents to control cement hydratation, shrinkage reduction agents, agents to reduce bleeding, rheology adjuvants, hydrophobic agents, agents for setting the pH-value and/or pigments.

9. Mixture of any one of claims 1 to 8, wherein the mixture is a mortar, in particular a dry mortar or a two-component mortar.

10. Process to prepare a curable mixture of at least of the preceding claims, comprising the step of mixing a fluoroorganic-substituted silicon compound which is adsorbed on a solid with at least one component of the curable mixture according to any one of claims 1 to 9.

1 1 . Process to prepare a curable mixture of at least one of claims 1 to 9, wherein in a first step a component (i) comprising the mineral binder and a component (ii) comprising the fluoroorganyl-substituted silicon compound which is adsorbed on a solid are prepared, and the further added substances are mixed with components (i) and/or (ii), and in a second step the components (i) and (ii) are mixed with one another.

12. Process to prepare a cured mixture, comprising the step of mixing the curable mixture of any one of claims 1 to 9 and/or the curable mixture prepared according to the process according to claim 10 or 1 1 with 1 to 120 wt.% water, based on 100 wt.% of curable, water-free mixture.

13. Cured mixture with hydrophobic and oleophobic properties obtainable according to the process according to claim 12.

14. Use of a fluoroorganic-substituted silicon compound which is adsorbed on a solid, in a hydraulically curable mixture containing more than 25 to 60 wt.% of hydraulically setting binder, 20 to 74 wt.% of at least one added substance, and 0.001 to 8 wt.% of the fluoroorganic-substituted silicon compound which is adsorbed on a solid, and optionally 0 to 40 wt.% of further adjuvants, based on 100 wt.% of curable, water-free mixture.

15. Use of a mixture of any one of claims 1 to 9 or a mixture prepared according to claim 10 or 1 1 mixture as tile grout, repair mortar, powder paint, adhesive putty, plaster, in particular top coat, as well as gypsum and/or lime and/or cement plaster, levelling mortar, trowelling compound, industrial flooring mass, bonding mortar, sealing compound, thermal insulation mortar, ceramic tile adhesive, primer, concrete paving tiles and/or as cement-based mass for crude oil, natural gas and/or geothermal heat boreholes, in order to obtain hydrophobic and oleophobic properties in the cured mixture.