TREATMENT COMPOSITION FOR PROVIDING A WATER-REPELLENT LAYER ON A SURFACE OF A SUBSTRATE

The present invention relates to a treatment composition for providing a water-repellent layer on a surface of a substrate, a kit-of-parts for providing the treatment composition, a method of treating at least a surface of a substrate, a substrate being treated with the treatment composition according to the invention and a structure comprising such substrate.

BACKGROUND OF THE INVENTION

Hydrophobic surfaces are used in many areas. Also, in the building industry hydrophobic surfaces are of paramount interest. A quality feature of hydrophobics, which is often desired by users, is the roll-off of water drops off the surface of a hydrophobic substrate (hereinafter beading effect).

Aqueous emulsions and pastes of alkoxysilane and alkoxysiloxanes are described in a variety of publications (e.g. EP 1 843 991 or EP 1 844 120). Building protection agents comprising such emulsions or pastes applied on a porous mineral substrate prevent the penetration of water into the substrate (hydrophobization), however, no or only weakly pronounced beading effects with limited durability are achieved (see example AE1).

In general, the use of water-based, oligomeric organosiloxanes with fluorinated alkyl groups are known as an anti-graffiti impregnation or as an "easy to clean" application. DE 199 55 047 discloses a composition containing at least one triaminoalkyl and fluoralkyl functional organosiloxane which can be used in particular for hydrophobization and I or oleophobation of surfaces, for "antigraffiti" applications. At the same time, however, these products are very expensive because high- priced products are required to produce them. Porous mineral building materials, such as concrete, may require the use of larger quantities in impregnation with the substances described in DE 199 55 047, which in some cases proves to be a disadvantage for use mainly for cost reasons. However, the beading effect of such treated surfaces steadily decrease over the time due to weathering effects (see example AE2).

DE 10 2009 000614 describes a fluorine-free composition for the hydrophobization of porous mineral substrates and for the generation of a beading effect on the surface of the substrate, wherein the composition is based on at least one hydrophobic active ingredient and at least one hydrophobic metal oxide. With storage, the hydrophobic metal oxide settles as precipitate and must be vigorously mixed before each application.

US 5,442,011 A reports organofluorosilicon compounds and emulsions containing said compound and their use to impart hydrophobic properties. The compounds disclosed therein, however, do not provide sufficient beading effects (see example AE4). The compounds disclosed therein also impair the optical properties of the surfaces treated therewith resulting in a partially glossy surface.

US 6,491 ,838 B1 teaches triamino- and fluoroalkyl-functional organosiloxanes which can be used as hydrophobicizing agents or for anti-graffiti applications. The organosiloxanes, however, do not provide sufficiently hydrophobic surfaces and the effects lack durability (see example AE1).

Generally, there are no means known in the art allowing for a beading effect to be achieved on mineral substrates with a long-lasting durability.

OBJECTIVE OF THE INVENTION

It is therefore the objective of the present invention to overcome the shortcomings of the prior art. It is a further objective of the present invention to provide a treatment composition that allows for the generation of a water-repellent layer on a surface of a substrate, particularly on mineral substrates. It is particularly desired that this water-repellent layer generates a beading effect on said surfaces. Especially, a long-lasting beading effect is of interest in the industry.

SUMMARY OF THE INVENTION

These objectives are solved by the treatment composition according to the invention for providing a water-repellent layer on a surface of a substrate, preferably by generating a beading effect thereon, comprising at least one siloxane compound comprising at least one building block according to formula (A)

R ^a4 ( (R ^a1 ,)c R ^a5 -|-N-R ^a3 _: -S yiOU ₍ fs-b-cj/z (A) (OR ^a2 ) _b wherein

R ^a1 is an alkyl group,

R ^a2 is selected from the group consisting of hydrogen, alkyl group and aryl group, R ^a3 is an alkanediyl group,

R ^a4 is selected from the group consisting of hydrogen, alkyl group and aryl group, R ^a5 is selected from the group consisting of hydrogen, alkyl group and aryl group, b is selected from 0, 1 and 2, c is selected from 0 and 1 , d is selected from 1 , 2 and 3, with the proviso that the sum of b and c ranges from 0 to 2; and at least one building block according to formula (F)

X-R ^f2 SiO(3-f)/2

(F) (OR ^f1 ) _f wherein

R ^f1 is selected from the group consisting of hydrogen, alkyl group and aryl group, R ^f2 is an alkanediyl group,

X is a partially or fully fluorinated C1-C18-alkyl group, f is selected from 0, 1 and 2 g is selected from 0 and 1 ; and at least one silane-based compound comprising at least two building blocks according to formula (P)

R ^p2 -SiO ₍₃ .p _)/2

(P)

(OR ^p1 ) _p wherein

R ^p1 is selected from the group consisting of hydrogen, alkyl group and aryl group, R ^p2 is selected from the group consisting of C3-C18-alkyl group and alkenyl group, p is selected from 0, 1 and 2.

The treatment composition according to the invention advantageously reduces the water-uptake of substrates treated therewith. It does not impair the optical properties of a surface treated therewith.

Preferred embodiments solving above described objections particularly well are described in the following description and in the dependent claims.

FIGURES

Figures 1 to 3 show photos of roof tiles treated with the treatment composition according to the invention immediately after said treatment (Fig. 1), after 300 h (Fig. 2) and after 1200 h of artificial weathering (Fig. 3), respectively. It can be seen from the photos that there is no deterioration of the beading effect over time.

Figure 4 shows a photo of two clay tiles protected with a terpolymer as described from US 5,442,011 A (left hand side) and a clay tile treated with the treatment composition according to the invention (right hand side), respectively, on which water droplets were placed in each case. It can be seen that the droplets on the clay on the left hand side are more spread indicating an inferior beading effect of the tile.

DETAILED DESCRIPTION OF THE INVENTION

Percentages throughout this specification are weight-percentages (wt.-%) unless stated otherwise. Concentrations given in this specification refer to the mass of the entire treatment composition unless stated otherwise. The term "alkyl" according to the present invention comprises branched or unbranched alkyl groups comprising cyclic and/or non-cyclic structural elements, wherein cyclic structural elements of the alkyl groups naturally require at least three carbon atoms. C1-CX-alkyl in this specification and in the claims refers to alkyl groups having 1 to X carbon atoms (X being an integer). C1-C8-alkyl for example includes, among others, methyl, ethyl, n-propyl, iso-propyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, sec-pentyl, tert-pentyl, neo-pentyl, hexyl, heptyl, n-octyl and iso-oc- tyl. The alkyl is optionally substituted. Substituted alkyl groups may theoretically be obtained by replacing at least one hydrogen by a functional group. The optional functional group is preferably selected from the group consisting of amino group, thiol group and halogen group. Unless stated otherwise, alkyl groups are preferably selected from substituted or unsubstituted C1-C8-alkyl, more preferably from substituted or unsubstituted C1-C4-alkyl.

The term "alkanediyl" is the corresponding group having two free valences (bonding sites). Sometimes, it is referred to as "alkylene" in the art. Said residues according to the present invention comprise cyclic and/or non-cyclic structural elements and can be linear and/or branched. C1-C4-al- kanediyl for example includes, among others, methane-1 ,1-diyl, ethane-1 ,2-diyl, ethane-1 ,1-diyl, propane-1 ,3-diyl, propane-1 ,2-diyl, propane-1 ,1-diyl, butane-1 ,4-diyl, butane-1 ,3-diyl, butane-1 ,2- diyl, butane-1 ,1-diyl, butane-2,3-diyl. Furthermore, individual hydrogen atoms bound to the alkanediyl compound may in each case be substituted by a functional group such as those defined above for the alkyl group. Unless stated otherwise, alkanediyl groups are preferably selected from substituted or unsubstituted C1-C8-alkanediyl, more preferably from substituted or unsubstituted C1-C4-alkanediyl.

The "alkenyl" is an unsaturated alkyl group comprising at least one olefinic (/.e. a C=C-double) bond. Above-described preferences for the alkyl groups apply for alkenyl groups mutatis mutandis.

The term "aryl" according to the invention refers to ring-shaped aromatic hydrocarbon residues, for example phenyl or naphthyl where individual ring carbon atoms are optionally replaced by N, O and/or S, for example benzothiazolyl. Furthermore, aryl groups are optionally substituted by replacing a hydrogen atom in each case by a functional group. The term C5-CX-aryl refers to aryl groups having 5 to X carbon atoms (optionally replaced by N, O and/or S) in the ring-shaped aromatic group (X naturally being an integer). C5-C6-aryl is preferred unless stated otherwise. "Arenediyl" is the divalent corresponding group to aryl, e.g. phenylene. Above-described preferences for the aryl groups apply for arenediyl groups mutatis mutandis.

The term "alkaryl" according to the invention refers to hydrocarbon groups comprising at least one aryl and at least one alkyl group such as benzyl and p-tolyl. The bonding of such an alkaryl group to other moieties may occur via the alkyl or the aryl group of the alkaryl group. Above-described preferences for the alkyl and aryl groups apply for alkaryl groups mutatis mutandis. If more than one residue - being it an atom, a group of atoms or entire building blocks - is to be selected from a given group, each of the residues is selected independently from each other unless stated otherwise hereinafter, meaning they can be selected to be the same members or different members of said group. The bonding sites in some chemical formulae herein may be emphasized by a wavy line (“ ./VW* “) as it is customary in the art.

Embodiments and preferences described for one aspect of the present invention apply mutatis mutandis for all the other aspects thereof unless technically unfeasible or stated otherwise. The repetition is omitted to improve the conciseness of the specification.

The treatment composition comprises:

1) the at least one siloxane compound comprising at least one building block according to formula (A) and at least one building block according to formula (F); as well as

2) the at least one silane-based compound comprising at least two building blocks according to formula (P).

The at least one siloxane compound comprises at least one building block according to formula (A):

R ^a1 is preferably a C1-C4-alkyl group, R ^a1 is more preferably a methyl group.

R ^a2 is preferably selected from the group consisting of hydrogen and C1-C4-alkyl group, R ^a2 is more preferably selected from the group consisting of hydrogen, methyl group and ethyl group even more preferably hydrogen to reduce the amount of volatile organic compounds (VOC). Preferably, each R ^a3 is independently selected from 1 ,2-ethanediyl and 1 ,3-propanediyl.

R ^a4 is preferably hydrogen. R ^a5 is preferably hydrogen, b preferably is selected from 0 and 1 .

Preferably, c is 0. d is preferably 1 or 2, more preferably 2.

It is preferred that R ^a3 is selected from 1 ,2-ethanediyl and 1 ,3-propanediyl, R ^a4 and R ^a5 are hydrogen, c is 0 and d is 1 or 2, preferably 2. This preference allows an improved beading effect to be obtained.

Particularly preferably, the at least one building block according to formula (A) is a building block represented by formula (A1) H ₂ N-(CH ₂ )2 ^— NH— (CH ₂ )2-NH-(CH ₂ )3 ^— SiO( _3.b ) _/2 (OR ^a2 ) _b ^{<A1 )} '

Most preferably, all building blocks according to formula (A) are represented by formula (A1). This particular preference is based on the finding of an significantly improved beading effect.

If the sum of b and c is 0, the building block according to formula (A) can be understood as T unit as the silicon atom of the building block is connected to three oxygen atoms which are usually connected to other building blocks according to formulae (A) or (F). It the sum of b and c is 1 , the building block according to formula (A) is a D unit; if said sum is 2, the building block according to formula (A) is a M unit. This analogously applies to the other building blocks described herein.

The at least one siloxane compound further comprises at least one building block according to formula (F):

^{X- R} g Si°(3-f)/2 z _F \

(OR ^f1 )f

R ^f1 is preferably selected from the group consisting of hydrogen and C1-C4-alkyl group, more preferably from the group consisting of hydrogen, methyl group and ethyl group, even more preferably hydrogen to reduce the amount of VOC liberated.

R ^f2 is preferably a C1-C8-alkanediyl group, more preferably a C2-C4-alkanediyl group, even more preferably a 1 ,2-ethanediyl group.

X is a partially or fully fluorinated C1-C18-alkyl group, i.e. at least one of the carbon atoms of the alkyl group carries at least one fluorine atom. X can for example be represented as C _x H _y Fz wherein x is an integer ranging from 1 to 18, y is an integer ranging from 0 to 2x and z is an integer ranging from 1 to 2x+1 with the proviso that the sum of y and z equals 2x+1 . X is preferably a partially or fully fluorinated C2-C10-alkyl group, more preferably a partially or fully fluorinated C4-C6-alkyl group. X is preferably a fully fluorinated alkyl group and X is then preferably represented as -(CF2)m-CF3-group with m being an integer ranging from 1 to 18, preferably 2 to 10, preferably from 4 to 8, ideally m is 5. f is preferably selected from 0 and 1 . g is preferably 1 . More preferably, g is 1 and X is -(CF2)m-CF3. Most preferably, g is 1 , R ^f2 is a 1 ,2-ethanediyl group and X is -(CF2)s-CF3.

It is preferred that R ^f2 is a 1 ,2-ethanediyl group and X is a partially or fully fluorinated C4-C6-alkyl group, more preferably -(CF2)s-CF3.

The numerical ratio of the building blocks according to formula (A) to the building blocks according to formula (F) in the siloxane compound preferably is 1 (building block according to formula (A)) to 1 to 5 (building blocks according to formula (F), even more preferably from 1 (building block according to formula (A)) to 1 .5 to 3 (building blocks according to formula (F).

Preferably, the at least one siloxane compound comprises at least one bond bridging the named building blocks according to formulae (A) and (F). Said bridge is usually formed by an oxygen atom present between the two silicon atoms of the individual building blocks. A siloxane compound comprising (at least) one building block according to formulae (A) and (F) each can exemplarily be depicted as follows:

The at least one siloxane compound preferably consists of the at least one building blocks according to formulae (A) and (F).

The treatment composition according to the invention preferably comprises the at least one siloxane compound in an amount of 0.1 to 20 wt.-%, more preferably from 0.5 to 15 wt.-%, even more preferably from 1 .0 to 2.5 wt.-%, based on the total weight of the treatment composition. If more than one siloxane compound is used in the treatment composition, the total amount of all siloxane compounds preferably lies in above ranges.

The at least one siloxane compound can be prepared by standard means known in the art. A possible preparation method is described in DE 199 55 047 A1 (see in particular paragraphs 25 to 35 and 40 to 47). In general, the at least one siloxane compound can be prepared by reacting appropriate aminoalkylalkoxysilanes and fluoroalkylalkoxysilanes. The silanes are mixed, alcohol is added if necessary, the mixture is jointly hydrolyzed and co-condensed and the alcohol including the hydrolysis alcohol is removed by distillation. The mixing of the alkoxysilanes can be performed in a temperature range between the solidification and boiling points of the silanes used. As a rule, excess water is added to the silane mixture to perform the hydrolysis. Hydrolysis or co-condensa- tion can also be carried out with a stoichiometric or a sub-stoichiometric amount of water. If the amount of water added during the reaction is limited to less than 3 moles of water per mole of silanes used, it is possible to produce essentially alkoxy-containing siloxane compounds.

In general, the reaction according to the invention is carried out at a temperature in the range of 0 to 100°C. Appropriately, the reaction according to the invention is carried out at a pH value of 4 to 12. Preferably, the hydrolysis is carried out at a temperature < 100°C, especially preferably at < 90°C and very especially preferably at < 60°C. As a rule, good mixing is ensured, for example by stirring. The reaction described here can also be carried out in the presence of a catalyst (e.g. hydrochloric acid, acetic acid or formic acid).

Preferably, the alcohol or hydrolysis alcohol is removed by distillation, whereby the distillation is preferably carried out at a temperature of < 90°C, particularly preferably at < 80°C, as well as suitably - since it is gentle on the product - under reduced pressure. The alcohol content of the composition is suitably reduced to 5 weight-% or less, preferably 1 weight-% or less, more preferably to 0.5 weight-% or less, even more preferably to 0.1 weight-% or less. Distillation can advantageously be carried out via a distillation column and continued until no more alcohol can be detected at the top of the column. If turbidity occurs, it can be removed from the product by filtration, sedimentation, centrifugation or similar standard procedures.

The at least one silane-based compound comprises (or preferably consists of) at least two building blocks according to formula (P). The at least two building blocks according to formula (P) are bound to each other by a joint oxygen atom present between the two silicon atoms of the individual building blocks. A silane-based compound consisting of two building blocks according to formula (P) can exemplarily be depicted as follows:

°(2-p) O _(2.p)

RP ² — Si-O - Si - R ^p2

(OR ^p1 ) _p (OR ^p1 ) _p

R ^p1 is preferably selected from the group consisting of hydrogen and C1-C4-alkyl group, more preferably from the group consisting of hydrogen, methyl group and ethyl group, even more preferably hydrogen to reduce the amount of VOC.

R ^p2 is preferably selected from the group consisting of C3-C18-alkyl group and vinyl group, R ^p2 is preferably a C3-C8-alkyl group, more preferably a C3-C4-alkyl group, even more preferably n-pro- pyl. The alkyl group of R ^p2 is optionally substituted wherein the at least one functional group is selected from the group consisting of halogen group (preferably chlorine and bromine), amino group (-NH2) and thiol group (-SH). Preferably, the alkyl group of R ^p2 is not substituted. p is preferably selected from 0 and 1 .

The at least one silane-based compound preferably comprises (or preferably consists of) 2 to 40, more preferably 2 to 20, even more preferably 2 to 8, building blocks according to formula (P). The number of building blocks can be determined by standard means known to the person skilled in the art. For example, it can be obtained by GPC (gel permeation chromatography). Generally, said method allows the determination of molecular masses or molecular weight as well as the molecular mass distribution. The GPC analysis method is described in detail in "Modern Size-Exclusion Liquid Chromatography", Andre Striegel et al., Wiley & Sons, 2nd ed., 2009. Preferable standards for calibration are polyethylene oxide/polyethylene glycol, measured on an Agilent 1100 device, using as eluent MEK (methylethylketone) with a flow rate of 1 ml/min and a column set consisting of MZ Gel SD plus columns.

The at least one silane-based compound preferably consists of the at least one building blocks according to formula (P).

The treatment composition preferably comprises the at least one silane-based compound in an amount of 1 to 30 wt.-%, more preferably from 2 to 20 wt.-%, even more preferably from 5 to 15 wt.-%, based on the total weight of the treatment composition. If more than one silane-based compound is used in the treatment composition, the total amount of all silane-based compounds preferably lies in above ranges.

The silane-based compound can be prepared by known means in the art. The preparation of the silane-based compound (especially propylethoxysilane oligomers) can be effected, for example, as described in US 2002/0090316 A1 (see in particular paragraphs 0021 and 0058 to 0062). For example, the silane-based compound can be prepared by controlled hydrolysis and condensation of suitable silanes such as trialkoxyalkylsilanes and trialkoxyalkenylsilanes or the respective trihalo- derivatives of the aforementioned (e.g. trichloropropylsilane), preferably in a suitable solvent such as ethanol. A suitable catalyst is preferably employed, e.g. a suitable pH adjuster such as hydrochloric acid. The controlled hydrolysis and condensation are preferably followed by a distillation step to remove the formed hydrolysis alcohol and the solvent, if any (vide supra). The preparation details described for the siloxane compound generally apply mutatis mutandis.

The mass ratio of the at least one silane-based compound and the at least one siloxane compound in the treatment composition preferably ranges from 1 to 20, more preferably from 2 to 10 and even more preferably from 5 to 8. Said mass ratio can be understood as the quotient of the (total) mass of the at least one silane-based compound and the (total) mass of the at least one siloxane compound. If more than one siloxane compound or more than one silane-based compound is used in the treatment composition, the mass ratio is based on the total amount of said compounds.

Preferably, the treatment solution comprises water. The amount of water in the treatment composition preferably ranges from 50 to 99 wt.-%, more preferably from 70 to 95 wt.-%, even more preferably from 88 to 92 wt.-%, based on the total weight of the treatment composition. This facilitates treating a surface of a substrate with the treatment composition and in particular allows to employ useful amounts of the active ingredients present in the treatment composition according to the invention.

To further improve the ecological aspects of the present invention, the total amount of organic solvents such as alcohols like methanol or ethanol is preferably 1 wt.-% or less, more preferably 0.1 wt.-% or less. Ideally, the treatment composition is free of organic solvents (disregarding trace impurities occasionally present in technical raw materials).

Optionally, the treatment composition comprises at least one pH adjuster. The at least one optional pH adjuster is a base or an acid depending on the desired pH value of the treatment composition. Suitable acids are inter alia inorganic and organic acids whereof organic acids are preferred. A useful inorganic acid is hydrochloric acid. Preferable organic acids are formic acid and acetic acid. Suitable bases are inter alia alkaline hydroxides such as sodium hydroxide, earth alkaline hydroxides and hydrogen carbonates such as NaHCOs.

The pH value of treatment composition preferably ranges from 4 to 6, more preferably from 4.4 to 5.2, even more preferably from 4.6 to 5.0. The pH value is measured in accordance with DIN EN ISO 10523 (2012). The at least one optional pH adjuster is preferably used in an amount necessary to adjust the pH value in accordance with above ranges.

Preferably, the treatment composition comprises at least one surfactant. Suitable surfactants can be selected based on routine experiments by the skilled artisan. Preferable surfactants are selected from the group consisting of alkyl sulfates having a C8-C18-alkyl group, alkyl ether sulfates and alkaryl ether sulfates having a C8-C18-alkyl group as hydrophobic group and from 1 to 40 ethylene oxide (EO) or propylene oxide (PO) units, alkylsulfonates having a C8-C18-alkyl group, al- karylsulfonates having a C8-C18-alkyl group, monoesters of sulfosuccinic acid with monohydric alcohols or alkylphenols having from 5 to 15 carbon atoms, alkali metal and ammonium salts of carboxylic acids having from 8 to 20 carbon atoms in the alkyl, aryl, alkaryl or aralkyl group, alkylphosphates and alkarylphosphates having from 8 to 20 carbon atoms in the organic group, alkyl ether phosphates or alkaryl ether phosphates having from 8 to 20 carbon atoms in the alkyl or alkaryl group and from 1 to 40 EO units, alkyl polyglycol ethers and alkaryl polyglycol ethers having from 8 to 40 EO units and from 8 to 20 carbon atoms in the alkyl or aryl groups, ethylene oxide-pro- pylene oxide (EO-PO) block copolymers having from 8 to 40 EO and PO units, addition products of alkylamines having C8-C22-alkyl groups with ethylene oxide or propylene oxide, alkyl polyglycosides having linear or branched, saturated or unsaturated C8-C24-alkyl groups and oligoglycoside radicals having from 1 to 10 hexose or pentose units, silicon-functional surfactants or mixtures of the aforementioned. Particularly useful surfactants are silicon-functional surfactants of the general formulae

R ^s1 R ^s1 OR ^s1

L-O-Si-O-L R ^s3 — Si-O- L L-O-Si-(CH ₂ ) _s -O-L R ^s2 , R ^s2 , OR ^s2 where R ^s1 and R ^s2 are independently selected from the group consisting of C1-C20-alkyl group and or phenyl group, preferably R ^s1 and R ^s2 are independently a C1-C10-alkyl group; R ^s3 is C1-C10-alkyl group, s is a integer ranging from 0 to 3; and

L is a surfactant radical selected from the group consisting of

— (CH ₂ -CH2-O) _V -(CH2-CH(CH ₃ )-O) _U -(CH2-CH2-O) _V -H where each t is an integer independently ranging from 3 to 15, u is an integer ranging from 3 to 50 and v is an integer ranging from 3 to 25, R ^s4 is selected from the group consisting of hydrogen, C1- C20-alkyl group, C2-C36-alkenyl group and C7-C36-aralkyl group.

Particular preference is given to a combination of at least one alkylsulfate having a C8-C18-alkyl group, for example lauryl sulfates, and at least one silicon-functional surfactants of the formula where each R ^s is independently methyl, ethyl, methoxy or ethoxy and the surfactant radical is where t is an integer ranging from 5 to 15 and R ^s5 is a C6-C10-alkyl group.

A surfactant of the above formulae in which each R ^s is a methyl group, n ranges from 1 to 30 and R ^s5 is isononyl is particularly suitable.

The amount of the at least one preferable surfactant preferably ranges from 0.02 to 2 wt.-%, more preferably from 0.3 to 1 .8 wt.-%, even more preferably from 0.6 to 1 .7 wt.-%, based on the total weight of the treatment composition. If more than one surfactant is used, the total amount of all surfactants preferably lies in above ranges.

The treatment composition according to the invention preferably comprises at least one preservative. This preservative advantageously improves the lifetime of the treatment composition. Suitable preservatives are known in the art. The amount of the preferred preservative preferably ranges from 0.01 to 1 wt.-%, more preferably from 0.1 to 0.3 wt.-%, based on the total weight of the treatment composition. Preferred preservatives are selected from the group consisting of chloromethyli- sothiazolinone, methylisothiazolinone and mixtures of the aforementioned.

The treatment composition according to the invention preferably comprises at least one defoamer. The amount of the at least one defoamer preferably ranges from 0.02 to 2 wt.-%, more preferably from 0.1 to 1 .0 wt.-%, even more preferably from 0.4 to 0.8 wt.-%, based on the total weight of the treatment composition. Defoamers are known in the art and the person skilled in the art can select a suitable defoamer based on routine experiments. A defoamer found particularly suitable is a mixture of foam-inhibiting polymers and hydrophobic solvents available under the tradename BYK 011 (obtainable from BYK-Chemie GmbH).

In addition to the components described hereinbefore, the treatment composition optionally comprises one or more customary auxiliaries selected from fragrances, corrosion inhibitors, rheological auxiliaries such as bentonites, catalysts such as organic tin, titanium or zirconium compounds, e.g. dibutyltin dilaurate, titanium alkoxides or zirconium alkoxides (e.g. tetrabutyl titanate). The optional one or more customary auxiliaries can be present in amounts of from 0.005 to 10 wt.-%, based on the total weight of the treatment composition.

Preferably, the total amount of alkyl silicates such as methyl silicate, ethyl silicate or propyl silicate is 1 wt.-% or less, preferably 0.1 wt.-% or less, based on the total weight of the treatment composition. Ideally, the treatment composition is free of alkyl silicates, in particular of methyl silicate, ethyl silicate and propyl silicate (disregarding trace impurities occasionally present in technical raw materials). Alkyl silicates may in some cases weaken the beading effect.

Preferably, the total amount of acrylates or polyacrylates, specifically fluoroacrylate or oligo- mers/polymers derived therefrom, in the treatment composition according to the invention is 1 wt.- % or less, preferably 0.1 wt.-% or less, based on the total weight of the treatment composition. Ideally, the treatment composition is free of said compounds (disregarding trace impurities occasionally present in technical raw materials). Acrylates or polyacrylates may in some cases weaken the beading effect.

Preferably, the total amount of hydrophobic metal oxides in the treatment composition according to the invention is 1 wt.-% or less, more preferably 0.05 wt.-% or less, even more preferably 0.005 wt.-% or less, based on the total weight of the treatment composition. Ideally, the treatment composition is free of hydrophobic metal oxides (disregarding trace impurities occasionally present in technical raw materials). Hydrophobic metal oxides in the context of the present invention are oxides, hydroxides and oxohydrates of aluminum, silicon and titanium, especially those treated with a hydrophobizing agent like fatty acids, fatty alcohols, alkyl silicates or alkylsilanes. Hydrophobic metal oxides may shorten the lifetime of the treatment composition according to the invention.

In one embodiment of the present invention, the treatment composition according to the invention comprises (or preferably consists of): the at least one siloxane compound, the at least one silane-based compound, water, at least one surfactant, preferably, at least one preservative, and optionally one or more customary auxiliaries.

Said components are preferably contained in amounts described hereinbefore.

The treatment composition according to the invention can be used to provide a water-repellent layer on a surface of a substrate. It can preferably be used to generate a beading effect thereon. It is advantageous that the treatment composition according to the invention allows for a long-lasting beading effect and at the same time provides an excellent reduction of water-uptake of a substrate treated therewith.

The treatment composition according to the invention can be prepared by mixing the components described hereinbefore. Preferably, the treatment composition according to the invention can be prepared by using the kit-of-parts described hereinafter.

The present invention concerns in another aspect a kit-of-parts for providing the treatment formulation according to the invention comprising part A and part B characterized in that part A comprises the at least one siloxane compound comprising at least one building block according to formula (A) and at least one building block according to formula (F); and part B comprises the at least one silane-based compound comprising at least two building blocks according to formula (P).

Part A preferably comprises the at least one siloxane compound in an amount of 1 to 40 wt.-%, more preferably in an amount of 5 to 30 wt.-%, based on the total weight of part A. If more than one siloxane compound is present in part A, the total amount of all siloxane compounds lies preferably in above ranges. Lower amounts increase the shipping cost while higher amounts might lead to instabilities of part A.

Preferably, part A is a dispersion or a solution, more preferably a solution, even more preferably an aqueous solution. Optionally, albeit not preferably, part A comprises at least one surfactant, such as the at least one surfactant described hereinbefore.

Preferably, part A comprises water. The amount of water in part A preferably ranges from 60 to 99 wt.-%, more preferably from 70 to 95 wt.-%.

Part B preferably comprises the at least one silane-based compound in an amount of 0.005 to 60 wt.-%, more preferably in an amount of 30.0 to 55.0 wt.-%, based on the total weight of part B. If more than one silane-based compound is present in part B, the total amount of all silane-based compounds preferably lies in above ranges. Lower amounts increase the shipping cost while higher amounts might lead to instabilities of part B. Preferably, part B is a dispersion, more preferably an emulsion, even more preferably an oil-in-wa- ter emulsion. The formulation of the dispersion or emulsion can be effected by standard means known in the art. Preference is given to a process using two stages with different pressures with a high-pressure homogenizer. A preferable method is described in WO 2006/081892 A1 (in particular as described on page 6, line 8 to page 7, last line). Preferably, part B comprises at least one surfactant, preferably the at least one surfactant described hereinbefore.

Preferably, part B comprises water. The amount of water in part B preferably ranges from 40 to 99.995 wt.-%, more preferably from 45 to 70 wt.-%. Optionally, part B comprises at least one pH adjuster. Optionally, part B comprises at least one preservative and/or at least one defoamer.

The optional one or more customary auxiliaries are typically comprised, if present, in part A. The amounts of the individual components present in parts A and B, respectively, of the kit-of-parts according to the invention can be varied widely and may even be outside above ranges. They are usually adjusted so that the desired quantities are present in the treatment composition according to the invention after mixing said parts in a predetermined ratio.

The mass ratio of part A to part B (used when mixing to obtain the treatment composition according to the invention) is typically adjusted such that the desired mass ratio of the at least one siloxane compound to the at least one silane-based compound in the treatment composition according to the invention is obtained.

In one embodiment of the present invention, the kit-of-parts according to the invention comprises part A and part B characterized in that part A comprises or consists of the at least one siloxane compound comprising at least one building block according to formula (A) and at least one building block according to formula (F); and water; and part B comprises or consists of the at least one silane-based compound comprising at least two building blocks according to formula (P); at least one surfactant; water; preferably, at least one preservative, and optionally, at least one pH adjuster.

Preferably, parts A and B comprise alkyl silicates such as methyl silicate, ethyl silicate or propyl silicate in a maximum amount of 1 wt.-% or less, preferably 0.1 wt.-% or less. Ideally, they are free of alkyl silicates, in particular of methyl silicate, ethyl silicate or propyl silicate (disregarding trace impurities occasionally present in technical raw materials) for the reasons laid out before. The same applies to acrylates or polyacrylates, specifically fluoroacrylate or oligomers/polymers derived therefrom, which are comprised in parts A and B in an uppermost amount of 1 wt.-% or less, more preferably of 0.1 wt.-% or less. Ideally, the treatment composition is free of said compounds. Preferably, the total amount of hydrophobic metal oxides in parts A and B is 1 wt.-% or less, more preferably 0.05 wt.-% or less, even more preferably 0.005 wt.-% or less. Ideally, the parts A and B are free of hydrophobic metal oxides. Preferably, parts A and B comprise organic solvents in a total amount of 1 wt.-% or less, preferably 0.1 wt.-% or less. Ideally, parts A and B are free of organic solvents.

The individual parts of the kit-of-parts according to the invention advantageously have a long shelflife of at least 12 months at room temperature (20 °C). The treatment composition according to the invention itself has only a limited shelf-life and advantageously is used within 72 h after its preparation, more preferably within 24 h. Thus, the kit-of-parts according to the invention allows the user to prepare the treatment composition according to the invention in a fast and easy manner shortly before its use.

In a further aspect, the present invention concerns a method of preparing the treatment composition according to the invention comprising mixing part A and part B of the kit-of-parts according to the invention. By mixing the parts A and B of the kit-of-parts according to the invention, the treatment composition according to the invention can easily be obtained without the need of special equipment. Mixing is preferably accompanied by stirring, e.g. with a mechanical stirrer. The parts are usually mixed for a time of 1 s to 30 min prior to use, preferably 1 min to 15 min. It is generally useful to mix the parts at a temperature ranging from 10 to 40 °C, preferably ranging from 15 to 25 °C.

In another aspect, the present invention is directed at a method of treating at least a (mineral) surface of a substrate comprising the method steps a) providing the (mineral) substrate comprising the surface; and b) treating the surface with the treatment composition according to the invention or a treatment mixture obtainable by mixing parts A and B of the kit-of-parts according to the invention; such that a treated surface of the substrate is obtained.

The method according to the invention significantly reduces the water-uptake of a treated substrate. The treated surface further has an improved beading effect. The treatment of the method according to the invention advantageously renders the treated surface hydrophobic. The method according to the invention comprises method steps a) and b). These method steps are carried out in the given order. The method according to the invention optionally comprises further method steps to be carried out before, after and/or between said method steps.

In method step a) of the method according to the invention, a substrate comprising a surface is provided. The substrate is preferably a mineral substrate, said mineral substrate preferably comprises or more preferably consists of at least one mineral material selected from the group consisting of concrete, limestone, sandstone, terracotta, marble, loam, cement, granite, sand, shale, artificial stone, plaster, clay and mixtures of the aforementioned.

Optionally, the (mineral) substrate is in the form of bricks, tiles, clinker, roof tiles, fiber cement boards or similar items used in the building industry.

Preferably, the mineral substrate comprises at least one fiber, more preferably a plurality of fibers. Even more preferably, the mineral substrate is a fiber-reinforced cement. Preferable fibers are selected from the group consisting of carbon fibers, cellulose fibers, (alkaline-resistant) glass fibers, (water-insoluble) polyvinyl alcohol fibers, homopolyacrylonitrile fibers and mixtures of the aforementioned.

The method optionally comprises a further method step a.i) pretreating the surface of the substrate.

The method step a.i) is to be carried out between method steps a) and b). Pretreatments are known in the art and include inter alia cleaning the surface (e.g. with an aqueous solution comprising a surfactant), chemical polishing (e.g. with an aqueous solution comprising an oxidant and/or an abrasive substance such as silica), high pressure or water vapor cleaning or abrasive brushing the surface and the like. The method step a.i) aims to make the surface more receptive for the treatment with the treatment composition according to the invention in method step b).

In method step b) of the method according to the invention, the surface of the substrate is treated with the treatment composition according to the invention.

The temperature of the treatment composition according to the invention in method step preferably ranges from 5 to 50 °C, more preferably from 10 to 40 °C, even more preferably from 15 to 25 °C.

The application quantity of the treatment composition according to the invention on the surface of the substrate in method step b) depends inter alia on absorptivity of the substrate. It preferably ranges from 1 to 1000 g/m ² , more preferably from 5 to 500 g/m ² , even more preferably from 30 to 350 g/m ² . The means of application in method step b) are not particularly limited. The surface of the substrate can be treated with the treatment composition according to the invention by means of spraying, dipping, brushing and flooding. Preference is given to spray applications e. g. with HVLP (High Volume Low Pressure) equipment as it usually achieves a very homogenous layer of the treatment composition according to the invention on the surface of the substrate.

The method according to the invention further optionally comprises the method step c) to be included after method step b) c) drying the substrate.

The substrate is preferably dried at a temperature of 10 °C to a temperature of 80°C. For energy saving reasons, preference is given to drying the substrate at ambient temperature (typically around 20 °C). Drying is preferably continued until all volatile components of the treatment composition according to the invention have been removed by evaporation. Conventential means of drying can be used without restrictions such as ovens, if needed.

The present invention further concerns an article comprising a substrate comprising at least one surface and at least one layer comprising at least one siloxane compound and at least one silane- based compound as described hereinbefore. Said layer is preferably in direct contact with the surface of the substrate. The article can thus be obtained by treating a substrate with the treatment composition according to the invention. Preferable articles in the context of the present invention are based on the substrates described hereinbefore such as bricks, tiles, clinker, roof tiles, fiber cement boards and similar items used in the building industry.

The present invention further concerns a (constructional) structure comprising at least one article as described hereinbefore. Said structure is preferably man-made. Exemplary structures in the context of the present invention are buildings and constructions such as walls, floors, bridges, tunnels, harbors (in particular harbor facilities and docks) and streets. The structures are for example made with one or more of the articles according to the invention.

The invention will now be illustrated by reference to the following non-limiting examples.

Examples

Commercial products were used as described in the technical datasheet available on the date of filing of this specification unless stated otherwise hereinafter. Unless stated otherwise herein, the last published version of standards before filing of the present specification were used. Artificial weathering (QUV-Test) was performed according to EN ISO 11507 (2007): Exposure of coatings to artificial weathering, unless stated to the contrary hereinafter. A Q-Lab weathering device, Modell QUV/basic from Q-Labs, was used (UVA-radiation 340 nm, using a weathering program with each cycle consisting of the following temperature and weathering steps: 1) 60 °C for 4 h, 2) followed by water condensation at 45 °C for 3 h 55 min, 3) water spraying for 5 min; the cycles were repeated continuously for the durations given below). The inventors have found that 300 h of artificial weathering using above cycle program corresponds to approximately 1 year of natural weathering in Southern Germany.

The reduction of water- uptake was measured with a Karstens tube (also referred to as RILEM tube in the art):

A glass measuring cylinder was attached to the surface of a substrate with putty and then filled with water to the 0 ml mark. The water-uptake was determined over the course of 24 h and compared to an untreated reference sample.

To determine the quality of the beading effect, water droplets were applied and, if not absorbed, wiped off after a contact time of 10 min and the remaining contact area was evaluated: 0 = droplet rolls off, 1 = no wetting, 2 = contact area half wetted, 3 = contact area completely wetted, 4 = dark coloration of the contact area, water droplet partially absorbed, 5 = dark coloration of the contact area, water droplet absorbed up to 50%, 6 = dark coloration of the contact area, water droplet completely absorbed.

The average droplet size and the width of the distribution can be determined using a Coulter® LS particle size analyzer, with, if necessary, the droplet size distribution being depicted graphically by plotting the percentage by volume of the droplets against the droplet diameter (this preferably on a logarithmic scale). In the case of a monomodal distribution, the curve has one maximum, and in the case of a bimodal distribution, it has two maxima. If the position of the maximum of such a distribution curve is reported in the following in pm, this reported value relates in the case of a bimodal or multimodal distribution to the first maximum having the smallest droplet diameter.

Preparation example 1 : preparation of a siloxane compound

A synthesis reactor comprising means for heating and distillation was filled with 26.5 g N-(2-Ami- noethyl)-N’-[3-(trimethoxysilyl)propyl]ethylenediamine, 153.0 g Triethoxy(3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluorooctyl)silane and 60 g ethanol. The mixture was heated for 2 h under reflux (approximately 80 °C). Then, 10.9 g water were added at 50 °C prior to heating the reaction mixture for a further 8 h under reflux (approximately 78°C). Thereafter, 16.3 g formic acid (85 wt.-% in water) and 860 g water were added at a temperature of approximately 50 °C. The alcohol was removed under reduced pressure (160-130 mbar, 48-50°C).

Preparation example 2: preparation of the silane-based compound A 2 liter jacketed stirring apparatus was charged with 1120.5 g n-propyltriethoxysilane (PTEO) and this initial charge was heated to approximately 80 °C. At this temperature, a mixture of 321 g ethanol, 76.5 g water and 1 .5 g (32 wt.-% in water) hydrochloric acid was added dropwise by a dropping funnel. The entire reaction mixture was subsequently heated to reflux for 4 h. Thereafter, the ethanol used and the ethanol released during the hydrolysis were removed by distillation, first at ambient pressure and then in vacuo. The liquid remaining at the bottom was the silane-based compound (780.8 g). The number of building blocks according to formula (P) in the silane-based compound produced was on average ranging from 3 to 7 (measured by gel permeation chromatography (GPC), vide supra).

Preparation example 3: preparation of a terpolymer (10.3 weiqht-% in water) based on US 5,442,011 A

A synthesis reactor comprising means for heating and distillation was filled with 2.66 g N-(2-Ami- noethyl)-N’-[3-(trimethoxysilyl)propyl]ethylenediamine, 15.34 g Triethoxy(3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluorooctyl)silane, 101.07 g silane-based compound of preparation example 2 and 6.48 g ethanol under a nitrogen blanket. The mixture was heated for 2 h under reflux (approximately 80 °C). Then, 5.21 g water were added at 45 °C within approximately 20 min prior to heating the reaction mixture for a further 8 h under reflux (approximately 78°C). Thereafter, 1 .49 g formic acid (85 wt.-% in water) was added at a temperature of approximately 50 °C within 15 min. The pH value of the reaction product was 4 (tested with pH paper). The reaction was then transferred into a reaction flask equipped with distillation bridge and filled with 1128 g of water. The alcohol was removed under reduced pressure (160-130 mbar, 48-50°C). The product obtained was a milky white, cloudy liquid over a white precipitate.

The product could not be formulated due to inhomogeneities and precipitates.

Preparation example 4: preparation of a terpolymer (10.3 weiqht-% in water) based on US 5,442,011 A

A synthesis reactor comprising means for heating and distillation was filled with 22.14 g 3-ami- nopropyltriethoxysilane, 51.04 g Triethoxy(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)silan e, 29.61 g n-propyltriethoxysilane and 20 g ethanol under a nitrogen blanket. The mixture was heated for 2 h under reflux (approximately 80 °C). Then, 8.1 g water were added at 45 °C within approximately 20 min prior to heating the reaction mixture for a further 8 h under reflux (approximately 78°C). Thereafter, 12.35 g formic acid (85 wt.-% in water) was added at a temperature of approximately 50 °C within 15 min. The pH value of the reaction product was 4 (tested with pH paper). The reaction was then transferred into a reaction flask equipped with distillation bridge and filled with 910.58 g of water. The alcohol was removed under reduced pressure (160-130 mbar, 48- 50°C). The product obtained was of a homogeneous, albeit slightly greenish appearance. Formulation example 1 : formulation of part B of the kit-of-parts

Components used:

The water-soluble components (#3, #4, #5, #6) were firstly dissolved in the initially charged water (#1) over a period of 5 to 10 min with stirring and the oil phase (#2) was then mixed in. The stirringin of air was avoided. Emulsification was subsequently carried out for 25 min in a high-pressure homogenizer APV Gaulin 15 (APV Gaulin GmbH, Lubeck) using 15 MPa in the first pressure stage and 3 MPa in the second pressure stage.

The resulting emulsion had an average droplet size of 0.319 pm. The emulsion was diluted with demineralized water in a ratio of 1 part per weight of the emulsion to 4 parts per weight of water to give the formulation example 1 (corresponds to part B of the kit-of-parts according to the invention).

Formulation example 2: Preparation of the treatment composition according to the invention

1 part per weight of the siloxane compound of preparation example 1 (corresponds to part A of the kit-of-parts according to the invention) was mixed with 10 parts per weight of formulation example 1 (corresponds to part B of the kit-of-parts according to the invention). The resulting treatment composition was stirred for 10 min and was then ready-for-use.

Application examples

In the application examples the following compositions AE1 to AE 4 were used:

AE1 : preparation example 1 (non-inventive)

AE2: formulation example 1 (non-inventive)

AE3: formulation example 2 (treatment composition according to the invention)

AE4: preparation example 4 (non-inventive)

Clay roof tiles Swiss TL 10 (obtained from ZZ Wancor) were treated with above compositions AE1 to AE 4 by spray application with HVLP equipment (HVLP Spray System Q3 Model, Fuji Industrial Spray Equipment Ltd. with nozzle sizes 1.3 mm) with the application quantities indicated in each case. After setting for 14 days, smaller tiles were sawn for the tests having each the dimensions of 15 x 7.5 x 1 cm. Table 1 : Initial Results after application.

While AE2 allowed for an equally good reduction of water- uptake compared to the treatment composition according to the invention, its beading effect was inferior. AE1 gave an equally good initial beading effect compared to the treatment composition according to the invention but the reduction of water- uptake was worse. In summary, none of the prior art solutions gave as good results as the treatment composition according to the invention directly after treatment. Additionally, the tiles treated of AE4 were inhomogeneously coated and partially glossy (island-like structures). The water-uptake remained almost unchanged over the course of the weathering (see table 2). In the left column of tables 2 and 3, the duration of the artificial weathering is given (denominated: QUV).

Table 2: Reduction of water- uptake after artificial weathering.

Table 3: Beading effect after artificial weathering.

The results of the artificial weathering show that the beading effect of the inventive examples was much more pronounced compared to the solutions of the prior art. Even after 1200 h of artificial weathering, there was no deterioration of the beading effect, the beading effect to the contrary improved overtime (see Figures 1 to 3) while the beading effect of the comparative examples worsened.

Other embodiments of the present invention will be apparent to those skilled in the art from a con- sideration of this specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope of the invention being defined by the following claims only.