Preparation containing organosilicium compound and its use

0001The present invention relates to the use of mixtures based on at least one water-soluble organic polymer and an organosilicon compound for protecting substrates from corrosion, mixtures based on at least one water-soluble organic polymer and an organosilicon compound and a method for producing these mixtures.

0002In chemistry, corrosion refers to the chemical reaction of a material with substances from its surroundings, whereby a measurable change occurs in the material. As a rule, the material is a metal. The term can also be applied to other materials such as glass, concrete, mortar and other mineral building materials. There are various types of corrosion, such as oxygen corrosion, which causes the formation of an oxide layer such as rust, hydrogen corrosion, also known as acid corrosion, hydrogen embrittlement, glass corrosion, which means the structural change in the surface of drinking glasses and other glass objects, and which does not mean optically through one more removable milky gray veil is visible, as well as bacterial anaerobic corrosion.

0003In order to suppress this phenomenon, there are a large number of different corrosion inhibitors which have been proposed in particular for the protection of steel in cementitious materials. Some are also powdery and can be dosed in this form or as a solution.

0004For example, the <patcit id="pcit0001" dnum="EP1176125A1"><text>EP 1 176 125 A1</text></patcit> aromatic sulfonic acid compounds and their metal salts for use in concrete and especially in repair mortars.

0005The <patcit id="pcit0002" dnum="GB1153178A"><text>GB 1 153 178</text></patcit> describes a combination of water-soluble chromate, nitrate or nitrite with a salt of an aromatic or heterocyclic amine as a corrosion inhibitor in concrete masses. In particular, it is disadvantageous that if the chloride content in the concrete is high, a comparatively high proportion of nitrite or nitrate must be introduced in order to be efficient. It is also not advantageous that the active ingredient is gradually consumed by a degradation reaction.

0006Furthermore describes the <patcit id="pcit0003" dnum="JP6345512A"><text>JP 6 345 512</text></patcit> Metal powder, such as Zn, Al, Mg, as a corrosion inhibitor in cement or polymer-modified cement.

0007Although all of these products are suitable as corrosion inhibitors for protecting steel in cementitious compositions, they have no or no significant influence on the water-repellent properties of such building materials.

0008To meet this requirement, the <patcit id="pcit0004" dnum="US20040103814A1"><text>US 20040103814 A1</text></patcit> a mixture of hydrophobizing agent, one or more alkanolamines, and optionally corrosion inhibitors, with specific requirements being placed on the hydrophobizing agent. However, these systems are liquid and can therefore not be added to a powdered dry mortar mixture. In addition, both water repellents and corrosion inhibitors must be added in order to perform both functions in the mortar.

0009Silanes and siloxanes as water repellents have been known for decades. These are usually only available in liquid form and are applied as a treatment agent to the hardened concrete. Since such agents are usually applied by spraying, it is often necessary to apply several steps in order to achieve the desired product consumption, ie the desired degree of application. This is not only time-consuming, but you are also heavily dependent on the weather conditions. For example, it shouldn't rain or wind heavily. So-called "creams" were developed to be able to apply larger quantities. However, these generally lead to poor penetration of the active ingredient into the substrate, which has a negative effect in particular on high-density substrates such as concrete. In addition, discoloration or at least an undesirable gloss or an oily appearance of the substrate surface can occur in the case of active ingredients with a higher degree of oligomerization, this being caused by the fact that higher oligomers do not penetrate into the substrate.

0010In addition, freeze-thaw salts or chloride-containing maritime environments require more than just water repellency for concrete protection, especially for reinforced concrete and steel reinforcement, since corroded metals in buildings significantly affect the resilience of buildings.

0011Out <patcit id="pcit0005" dnum="EP1205481A2"><text>EP 1 205 481 A2</text></patcit> Mixtures of n-propylethoxysiloxanes and their emulsions for the impregnation of mineral substrate surfaces are known. These mixtures are applied in liquid form to the hardened surfaces, whereby repeated application is often necessary, or at least helpful.

0012The <patcit id="pcit0006" dnum="EP1308428A2"><text>EP 1 308 428 A2</text></patcit> describes the use of liquid silanes or silane preparations as corrosion inhibitors, these being essentially applied to the surface of the cured substrate. Silanes and silane preparations in powder form are not described.

0013<patcit id="pcit0007" dnum="EP0913370A1"><text>EP 0 913 370 A1</text></patcit> discloses a method for producing a homogeneously hydrophobized concrete, also called mass hydrophobization, whereby the absorption of NaCl solutions is also significantly reduced. For this purpose, an aqueous emulsion containing hydrolyzable organosilicon compounds is added, which contains at least one alkoxysilane and optionally an organosilicon compound acting as a surfactant. These systems are liquid and cannot easily be converted into powder, which makes them difficult to store and transport, especially at temperatures below freezing. In addition, it is not possible to produce dry mortar and / or powdery compounds for the production of concrete containing such systems.

0014<patcit id="pcit0008" dnum="EP0228657A2"><text>EP 0 228 657 A2</text></patcit> teaches, among other things, to use water-redispersible or water-soluble, water-free powders based on at least one organic silicon compound as additives for plasters, hydraulic binders, clay or paints, dissolved in water for the hydrophobization of bulk materials or as binders for finely divided inorganic or organic substances . The use of these powders for the hydrophobization of cement systems and / or for protecting the systems against corrosion, in particular of metal, which is surrounded by mineral building materials, is not mentioned. In addition, these powders cannot be easily produced, which further complicates their production, storage and use.

0015In the <patcit id="pcit0009" dnum="EP0811584A1"><text>EP 0 811 584 A1</text></patcit> Cementary materials are mentioned in powder form, containing a granulated hydrophobizing additive, which contains 5 to 15 wt .-% of an organopolysiloxane component, 10 to 40 wt .-% of a water-soluble or water-dispersible binder and 50 to 80 wt .-% of a carrier particle. The cementitious material causes hydrophobicity. There is no mention that these products can be used to protect against corrosion. Another disadvantage is that the organopolysiloxane, which is mainly responsible for the hydrophobicity, is only present in very small amounts in the additive. Therefore, a larger amount must be used accordingly, which in turn can lead to adverse effects from the other components, such as the binder and the carrier particles.

0016Unfortunately, all these measures for equipping and maintaining buildings are not sufficient and therefore do not meet the high requirements. In particular, the surface treatment or the hydrophobization of building blocks or structures with previously known means and measures is not sufficiently effective to reduce the corrosion of the materials, in particular steel reinforcements. It is well known that, in addition to stress cracks, the structure of the building initially becomes cracked or worn down, particularly as a result of environmental and weather influences, as a result of which substances penetrating into the building structure lead to further damage to the buildings.

0017The object was therefore to provide a material for protecting materials against corrosion, which can be added to dry formulations, in particular in powder form, but can also be used as a liquid preparation. It is important that the powder is easy to manufacture and stable in storage. When added to a dry formulation, it should be easily wettable and the material should disperse, redisperse or dissolve well to ensure quick and optimal distribution. It is important that the material in the matrix mixed with water can develop its full effect. In addition, it should have no toxic properties and have no or very little interaction with the hydraulically setting component, so that, for example, there is no delay in setting the mineral-setting component.

0018Surprisingly, this complex task was solved through the use a water-dispersible, redispersible or soluble mixture (hereinafter also referred to briefly as a powder), based on at least one water-soluble organic polymer and at least one organosilicon compound, or at least one water-soluble organic polymer, composition containing at least one organosilicon compound and water for the protection of substrates against corrosion. According to the invention, the object was advantageously achieved in accordance with the details of the claims.

0019The present invention therefore relates to the use of at least one water-dispersible, redispersible or soluble mixture based on at least one<ol id="ol0001" compact="compact"><li>(i) at least one water-soluble organic polymer and</li><li>(ii) at least one organosilicon compound,</li></ol>or a composition containing at least components (i) and (ii) and water for the protection of substrates against corrosion.

0020Mixtures according to the invention or mixtures used according to the invention preferably based on at least one component (i) from the series polyvinyl acetate, polyvinyl alcohol, polyvinyl pyrrolidones, starches, starch derivatives, polyacrylates, polymethylacrylates, polymaleinates, water-soluble cellulose ethers, water-soluble polyethylene oxides, water-soluble proteins - to name just a few examples. However, other water-soluble polymers can also be used as component (i). Here and below, the respective disclosure on component (i) of the present application is also to be attributed to components (iii) and (v), and the same applies vice versa.

0021A very large number of organosilicon compounds can be used as component (ii), "organofunctional" being equated with "organo" in the context of the present invention, which means that the silicon compound has at least one substituent with at least one carbon atom. Preferred organosilicon compounds are selected from the group of organofunctional silanes, polysilanes, silane esters, siloxanes, silicones and / or silicic acid esters. In particular, said organosilicon compounds can be used as individual components, as mixtures of at least two organofunctional silanes, as mixtures of at least two organofunctional siloxanes or as mixtures of, for example, at least one organofunctional silane and at least one organofunctional siloxane. Here and below, the respective disclosure on component (ii) of the present application is also to be attributed to components (iv) and (vi), and the same applies vice versa.

0022It is often advantageous, but not mandatory, if the said organosilicon compound is in liquid form and the boiling point at normal pressure of the organosilicon compound used is not too low, preferably about 100 ° C. or more. They can be soluble, insoluble or only partially soluble in water. Compounds which have no or only a limited solubility in water are often preferred, for example silicic acid esters with the formula Si (OR ')₄, Polysilanes of the formula R.₃Si (SiR₂)_nSiR₃ with R equal to n = 0 to 500, n = 0 to 8 being preferred, di-, oligo- and polysiloxanes or their mixtures of the general formula or empirical formula R._cH_dSi (OR ')_e(OH)_fO_{(4-cdef) / 2} with c = 0 to 3, d = 0 to 2, e = 0 to 3, f = 0 to 3 and the sum c + d + e + f not more than 3.5, where each R 'is independently an alkyl or alkoxyalkylene radical 1 to 4 carbon atoms and preferably methyl or ethyl, groups R are identical or different and branched or unbranched alkyl radicals having 1 to 22 carbon atoms, cycloalkyl radicals having 3 to 10 carbon atoms, alkylene radicals having 2 to 4 carbon atoms Represent aryl, aralkyl, alkylaryl radicals having 6 to 18 carbon atoms, wherein said radicals R can also be substituted with halogens, such as F or Cl, with ether, thioether, ester, amide, nitrile, hydroxyl, amine, carboxyl, sulfonic acid, epoxy, carboxylic anhydride and carbonyl groups can, whereby in the case of the polysilanes R can also have the meaning OR '.

0023Preferred organosilicon compounds according to (ii) are in particular mixtures of alkylalkoxysiloxanes of the empirical formula (R ") Si (OR" ')_xO_y with 0 &lt;x &lt;2 and 0.5 &lt;y &lt;1.5, preferably 1.0 &lt;x &lt;2.0 and 0.5 &lt;y ≤ 1.0 with the proviso (2y + x) = 3, and groups R "are the same or different and R" represents a linear, branched or cyclic alkyl group with 1 to 18 carbon atoms, furthermore groups R '"are the same or different and R'" for a hydrogen or a linear or branched alkyl group with 1 to 4 carbon atoms, preferably H, methyl, ethyl, propyl.

0024Also preferred as organosilicon compounds according to (ii) are tetraalkoxysilanes, alkyltrialkoxysilanes, dialkyldialkoxysilanes, linear and / or branched C₁- to C₂₀-Alkyl groups and linear and / or branched C as alkoxy groups₁-to C₁₀- Alkoxy groups can be present, the latter preferably using methoxy, ethoxy and / or i-propoxy groups. In addition, a copolymerizable alkylene group, such as a vinyl, allyl and / or (meth) acrylic group, can also be used instead of an alkyl group.

0025Non-limiting examples of preferred organosilicon compounds for the purposes of the present invention are organofunctional silanes or Siloxanes from the series of alkoxysilanes, such as hydrogen trimethoxysilane, hydrogen triethoxysilane, tetramethoxysilane, tetraethoxysilane, the alkylsilanes, such as methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n- and i-propyltrimethoxysilane, n- and i-propyltriethoxysilane, n- and i-butyltrimethoxysilane, nyl and nyltrimethoxysilane, i-butyltrimethoxysilane, i-butyltrimethoxysilane, - and i-pentyltriethoxysilane, n- and i-hexyltrimethoxysilane, n- and i-octyltrimethoxysilane, n- and i-octyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, dimethyldimethoxysilane, di-methyldiethoxysilane, n- and i-butylmethyldimethoxysilane, n- and i-butylmethyldiethoxysilane, cyclohexylmethyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, and isobutyl Isopropyldimethoxysilane, the vinylsilanes, such as vinyltrimethoxysilane, vinyltriethoxysilane, Vinylmethyl dialkoxysilane and vinyl tris (2-methoxyethoxysilane), the aminoalkoxysilanes, such as 1-aminomethyltrimethoxysilane, 1-aminomethyltriethoxysilane, 2-aminoethyltrimethoxysilane, 2-aminoethyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminooxysobutyltriloxysilane Aminopropylmethyldiethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropyltriethoxysilane, triaminofunctional propyltrimethoxysilane and 3- (4,5-dihydroimidazolyl) propyltriethoxysilane, the glycidyl ether or Glycidylalkylfunktionellen alkoxysilanes such as 3-glycidyloxypropyltrimethoxysilane and 3-glycidyloxypropyltriethoxysilane, the chlorine and fluoroalkyl-functional alkoxysilanes such as Tridecafluorooctyltriethoxysilan and Tridecafluorooctyltrimethoxysilan, -3Chlorpropyltriethoxysilan of acrylic or methacrylic functional alkoxysilanes such as acryloxypropyltrimethoxysilane, acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxyisobutyltrimethoxysilane, 3-methacryloxyisobutyltriethoxysilane, 3-methacryloxy-2-methyl-propyltrimethoxysilane and 3-methacryloxy-2-methyl-propyltriethoxysilane, the mercapto-functional alkoxysilanes, such as 3-mercaptopropyltrimethoxysulfane, 3-mercaptopropyltrimethoxysulfane, 3-mercaptopropyltrimethoxysulfane, 3-mercaptopropyltrimethoxysulfane and 3-mercaptopropyltrimethoxysulfane Alkoxysilanes, such as bis (triethoxysilylpropyl) tetrasulfane, bis (trimethoxysilylpropyl) tetrasulfane, bis (triethoxysilylpropyl) disulfane, Bis- (trimethoxysilylpropyl) disulfane, bis- (triethoxysilylpropyl) sulfane, bis- (trimethoxysilypropyl) sulfane, bis- (triethoxysilylpropyl) pentasulfane and bis- (trimethoxysilylpropyl) pentasulfane, with corresponding monosilanes in the aforementioned Oligomers due to hydrolysis can be present in a concentration of 0.001 to 5%, based on the composition, further organosilicon compounds such as beta-nitrilethyltriethoxysilane, arylsilanes, in particular phenyltriethoxysilane, but also dipropyldiethoxysilane, triphenylsilanol and their preferably liquid condensation products, silanes containing quaternary ammonium groups, in particular amino-functional silanes or siloxanes, carboxylic acid and carboxylic anhydride-functional silanes, disilanes such as dimethyltetraalkoxydisiloxydisilialis, trimethylsilane trimethyldisiloxane corresponding chlorine compounds available (co) condensates. Preference is also given to methylhydrogenpolysiloxanes blocked by trimethylsiloxy groups, copolymers of dimethylsiloxane and methylhydrogensiloxane units blocked by trimethylsiloxy groups, and dimethylpolysiloxanes each having an Si-bonded hydroxyl group in the terminal units as well as the organofunctional siloxanes, such as vinyl-functional siloxanes, alkyl-functional siloxanes, vinyl / alkyl-functional siloxanes (cocondensates), methacrylic-functional siloxanes, Amino-functional siloxanes, aminoalkyl / alkyl-functional siloxanes, aminoalkyl / fluoroalkyl-functional siloxanes or corresponding cocondensates and condensates such as, for example, but not exclusively, from <patcit id="pcit0010" dnum="EP0590270A"><text>EP 0 590 270 A.</text></patcit>, <patcit id="pcit0011" dnum="EP0716127A"><text>EP 0 716 127 A.</text></patcit>, <patcit id="pcit0012" dnum="EP0716128A"><text>EP 0 716 128 A</text></patcit>, <patcit id="pcit0013" dnum="EP0748357A"><text>EP 0 748 357 A</text></patcit>, <patcit id="pcit0014" dnum="EP0760372A"><text>EP 0 760 372 A</text></patcit>, <patcit id="pcit0015" dnum="EP0814110A"><text>EP 0 814 110 A</text></patcit>, <patcit id="pcit0016" dnum="EP0879842A"><text>EP 0 879 842 A</text></patcit>, <patcit id="pcit0017" dnum="EP0846715A"><text>EP 0 846 715</text></patcit>, <patcit id="pcit0018" dnum="EP0930342A"><text>EP 0 930 342 A</text></patcit>, <patcit id="pcit0019" dnum="EP1101787A"><text>EP 1 101 787 A</text></patcit>, <patcit id="pcit0020" dnum="EP1205481A"><text>EP 1 205 481 A</text></patcit>, <patcit id="pcit0021" dnum="EP1304345A"><text>EP 1 304 345 A</text></patcit>, <patcit id="pcit0022" dnum="WO06081891A"><text>WO 06/081891</text></patcit>, <patcit id="pcit0023" dnum="WO06081892A"><text>WO 06/081892</text></patcit>, <patcit id="pcit0024" dnum="WO06010666A"><text>WO 06/010666</text></patcit>, <patcit id="pcit0025" dnum="DE19649953A"><text>DE 196 49 953 A</text></patcit>, <patcit id="pcit0026" dnum="DE19649955A"><text>DE 196 49 955 A</text></patcit>, <patcit id="pcit0027" dnum="DE19725516A"><text>DE 197 25 516 A</text></patcit>, <patcit id="pcit0028" dnum="DE19818923A"><text>DE 198 18 923 A</text></patcit>, <patcit id="pcit0029" dnum="DE19823390A"><text>DE 198 23 390 A</text></patcit>, <patcit id="pcit0030" dnum="DE19834990A"><text>DE 198 34 990 A</text></patcit>, <patcit id="pcit0031" dnum="DE19849308A"><text>DE 198 49 308 A</text></patcit>, <patcit id="pcit0032" dnum="DE19904132A"><text>DE 199 04 132 A</text></patcit>, <patcit id="pcit0033" dnum="DE19908636A"><text>DE 199 08 636 A</text></patcit> such as <patcit id="pcit0034" dnum="DE10056344A"><text>DE 100 56 344 A</text></patcit> can be seen, or oligomeric silicic acid esters, for example Dynasylan^® 40 or such <patcit id="pcit0035" dnum="DE2744726C"><text>DE 27 44 726 C</text></patcit> such as <patcit id="pcit0036" dnum="DE2809871C"><text>DE 28 09 871 C</text></patcit>, including hydrogen cyclosiloxanes, for example so-called D_nH compounds with a degree of oligomerization of n = 2 to 20, in particular of n = 4 to 6.

0026The production of the organosilicon compounds mentioned can also be carried out by methods as described in<nplcit id="ncit0001" npl-type="s"><text> Noll, Chemistry and Technology of Silicones, 2nd edition 1968</text></nplcit>, Weinheim and <nplcit id="ncit0002" npl-type="b"><text>Houben-Weyl, Methods of Organic Chemistry, Volume E 20, pp. 1782 f, 2219 f, Georg Thieme Verlag, Stuttgart, 1987</text></nplcit> are described.

0027According to the invention, a present mixture can be added in a simple and economical manner during the production of mineral building materials. In particular, mixtures or powders that are present can be used advantageously when preparing building material masses from the individual components or additives or ready-to-use building material mixtures on site, ie directly at the location of the subsequent processing of the building material mass, or in the production of ready-to-use, powder-form building material mixtures, for example concrete, plaster or mortar mixtures, or in the production of ready-to-use, powder-form additives for building material masses, for example cement, lime, sand or rheology aids. add.

0028The use of the present mixtures according to the invention protects substrates, in particular metal, and / or natural and / or artificially produced mineral building materials from corrosion. Preferred metals are iron and iron alloys, in particular steel and aluminum and aluminum alloys. The metal is usually surrounded by mineral building materials, such as steel reinforcements in concrete. Preferred building materials are mortar, concrete, plaster, grout, brick material, bricks, building blocks, components and / or natural stone, such as sand-lime brick.

0029Mixtures according to the invention are preferably used in and / or on mineral building materials which are in contact with metal, envelop or enclose metal. Mineral building materials such as concrete, in particular reinforced concrete, aerated concrete, gas concrete, foam concrete, prefabricated components made of concrete, mortar, plasters, jointing compounds, components made of sand-lime brick, clinker, brick, porous tiles and tiles, terracotta, natural stones, fiber cements, screeds, clay articles are particularly preferred , Masonry, facades, roofs and structures such as bridges, port facilities, residential buildings, industrial buildings and publicly used buildings such as car parks, train stations or schools, but also finished parts, such as railway sleepers or L-stones.

0030The mineral building materials to be produced artificially generally contain a mineral binder which comprises at least a) a hydraulically setting binder, in particular cement, b) a latent hydraulic binder, in particular acid blast furnace slag, puzzolans and / or metakaolin, and / or c) a non- hydraulic binder, which reacts under the influence of air and water, in particular calcium hydroxide and / or calcium oxide, is used.

0031Cement, in particular Portland cement, for example according to EN 196 CEM I, II, III, IV and V, calcium sulfate in the form of alpha and / or beta hemihydrate and / or anhydrite and / or alumina cement is preferred as the hydraulically setting binder. Puzzolans such as metakaolin, calcium metasilicate and / or volcanic slag, volcanic tuff, trass, fly ash, blast furnace slag and / or silica dust can be used as latent hydraulic binders, which react hydraulically together with a calcium source such as calcium hydroxide and / or cement. In particular, lime, mostly in the form of calcium hydroxide and / or calcium oxide, can be used as the non-hydraulic binder which reacts under the influence of air and water. Purely Portland cement-based systems or a mixture of Portland cement, alumina cement and calcium sulfate are preferred, it being possible for latent hydraulic and / or non-hydraulic binders to be added to both systems.

0032Often, binders or combinations of binders are preferred which, together with water, produce a high pH. This causes, when in contact with a metal, on its surface an oxidized passive layer to which the organosilicon compound can bind.

0033The mineral binders are typically mixed with additives, which are sometimes also called fillers. Typical additives are quartzitic and / or carbonate sands and / or flours such as quartz sand and / or limestone powder, carbonates, silicates, chalk, layered silicates and / or precipitated silicas. Furthermore, light fillers, such as hollow glass spheres made of glass, polymers such as polystyrene spheres, aluminum silicates, silicon oxide, aluminum silicon oxide, calcium silicate hydrate, aluminum silicate, magnesium silicate, aluminum silicate hydrate, calcium aluminum silicate, calcium silicate hydrate, silicon dioxide and / or aluminum-iron-magnesium-silicate, but also clays such as bentonite are used, the fillers and / or light fillers can also have a natural or artificially produced color.

0034If silane products with a hydrophobic effect are used as the organosilicon compound, the corrosion properties of building materials and structures equipped with appropriate steel or metal reinforcements can also be significantly improved once again due to the hydrophobing effect achieved - also compared to conventional corrosion protection measures.

0035Surprisingly, it was also found that, in addition to the use according to the invention as a corrosion inhibitor, the mixture can also be used for stone consolidation, with hydrophobic properties and effects remaining undamaged.

0036In particular, it is surprising that, in addition to a hydrophobizing and / or stone-hardening effect of agents which contain organofunctional silanes and / or organofunctional siloxanes, at the same time a corrosion-inhibiting effect, in particular metal corrosion or corrosion in concrete which comes into contact with water and salts, through the use of the aforementioned powder in repair compounds or in quantities for the production of building blocks, components or Buildings can achieve advantageous. The use according to the invention thus advantageously also includes the simultaneous avoidance of metal and stone corrosion.

0037In addition, when applying a powder according to the invention in such masses, good and, in particular, uniform stone-hardening properties can be determined on the later structure. Hydrophobic properties and effects also remain unaffected.

0038Furthermore, it is advantageous if a powder or mixture specified in more detail above is used according to the invention for the production of mineral compositions for repair purposes in the construction sector. Such an application can also significantly alleviate a corrosion process, at least over time.

0039A protective action against corrosion according to the invention is achieved if the rate of corrosion is reduced by more than about 50%, preferably by more than about 80%, in particular by more than about 90%, in comparison to unprotected materials. In the case of steel reinforcement, the rate of corrosion is determined, for example, by the observed corrosion currents compared to corresponding unprotected concrete.

0040The amounts of a mixture according to the invention in the concrete, based on the solids content of the mixture and the cement content in the concrete, can be up to about 5% by weight or more, care being taken to ensure that any standard regulations are observed. The amounts used are preferably set such that optimum corrosion protection is obtained for the use according to the invention. This means that a high active substance content of organosilicon compound can be used without significantly influencing the other concrete properties, whereby the construction guidelines can also be easily complied with.

0041The amounts of a mixture according to the invention in mortars, based on the solids content of the mixture and the dry fraction of the mortar, are from about 0.01 to about 10% by weight, it being possible for higher amounts to be used for special applications. About 0.05 to about 5% by weight, in particular about 0.1 to 3% by weight, of the mixture is preferably used.

0042The mixtures according to the invention, which surprisingly work well as corrosion inhibitors, are typically incorporated into hydraulically setting compositions, and are generally added together with the other components during the production of the mineral building materials.

0043Mixtures according to the invention are generally in powder form. In this way, they can be processed in a particularly simple and economical manner in corresponding dry mortars, dry plasters and / or dry premixes for concrete, such as cement, in particular modified cements. This enables particularly good dosing and a very even distribution of the mixture in the later building material mass and thus also in the subsequently produced building blocks, components and the structure obtained thereby. These dry mixes can then simply be mixed on site with the addition of a defined amount of water and then processed.

0044However, a mixture according to the invention can also be mixed in as a separate component in the preparation of the building material mass. In this embodiment, it is often advantageous to mix or knead the building material components with the necessary amount of water, the mixture being added directly before, during and / or after the addition of water. But you can also add the mixture to the mixing water first and add it to the dry or already moist mass in the mixer.

0045However, the said mixtures can also be applied on the surface in dissolved, preferably low-viscosity to high-viscosity, ie pasty form, to the building materials obtained as surface protection, for example by spraying, brushing, rolling or knife coating. You can use the present composition or preparation in an amount of more than 50 g / m², preferably more than 100 g / m², particularly preferably more than 200 g / m², apply to the substrate surface. If necessary, a multiple application with a drying time of, for example, 2 hours to about 2 days can be applied between the work steps, in particular if the desired amount of active ingredient cannot be applied in one work step due to the substrate's low absorbency. If said mixture is used as a powder, it is advantageous for this application if the powder is previously dispersed, redispersed or dissolved in water; other liquids that evaporate at ambient temperature can also be used for this.

0046The present invention also relates to a water-dispersible, redispersible or soluble mixture based on<ul id="ul0001" list-style="none" compact="compact"><li>(iii) at least one water-soluble organic polymer and</li><li>(iv) at least one organosilicon compound with at least one Si-O-Si and / or with at least one Si-Si bond, wherein the content of organic polymer (iii), based on the sum of the organic</li></ul>

0047Polymer (iii) and the organosilicon compound (iv), between about 40 and about 80 wt .-%, preferably from 40 and about 70 wt .-%, in particular from 45 to 60 wt .-%.

0048As organic polymers of component (iii), the organic polymers according to component (i) already disclosed above can advantageously be used or used as a basis.

0049The organosilicon compound according to (iv) with at least one Si-O-Si bond can also advantageously be those according to component (ii) disclosed above, in particular organosiloxanes such as alkylalkoxysiloxanes or alkylalkoxysiloxane mixtures and / or oligomeric silicic acid esters. Furthermore, one or more polysilanes are used as organosilicon compound according to (iv) with at least one Si-Si bond. It is also possible to use a mixture of different organosilicon compounds.

0050The present invention furthermore relates to a water-dispersible, redispersible or soluble mixture based on<ul id="ul0002" list-style="none" compact="compact"><li>(v) at least one water-soluble organic polymer and</li><li>(vi) at least one organosilicon compound,</li></ul>wherein the organosilicon compound is an oligomer mixture of alkylalkoxysiloxanes, the oligomer mixture contains 50 to 100% by weight of alkylalkoxysiloxanes and these essentially have a degree of oligomerization of 2 to 20.

0051Again, the organic polymers of component (v) used or based on the organic polymers according to component (i) or (iii) already disclosed above.

0052As organosilicon compound according to (vi) it is also possible here to advantageously use those of component (ii) or (iv) disclosed above, in particular organosiloxanes such as alkylalkoxysiloxanes or alkylalkoxysiloxane mixtures or as starting material in the preparation of mixtures or powders according to the invention.

0053For the mixtures according to the invention and the mixture for the use according to the invention it will generally be preferred if the organosilicon compound is a liquid at room temperature and normal pressure. For powders according to the invention in particular, it is advantageous if the boiling point of the organosilicon compound at normal pressure is approximately 100 ° C. or higher, preferably approximately 125 ° C. or higher, in particular approximately 150 ° C. or higher.

0054If the organosilicon compound is a liquid at room temperature and normal pressure, the viscosity can be very low, but also very high, depending on the compound. For the mixtures and use according to the invention, however, it is often advantageous if low-viscosity organosilicon compounds are used. They preferably have a viscosity of about 1 to 1000 mPa s, particularly preferably from about 2 to 200 mPa s, in particular from about 3 to 50 mPa s, and very particularly preferably from about 3 to about 20 mPa s. The viscosity measurement is generally carried out in accordance with DIN 53 015.

0055Oligomeric silanes or organosiloxanes such as alkylalkoxysiloxanes are generally characterized by their degree of oligomerization and by their structure. This is explained in more detail below using the example of n-propylethoxysiloxanes and their mixtures. These organosilicon compounds can be approximately represented by the following general structural formulas:<chemistry id="chem0001" num="0001"><img file="EP1982964A1_D0001.tif" /></chemistry>for linear n-propylethoxysiloxanes and<chemistry id="chem0002" num="0002"><img file="EP1982964A1_D0002.tif" /></chemistry>for cyclic n-propylethoxysiloxanes, where n indicates the degree of oligomerization. That is, the degree of oligomerization reflects the number of Si units per molecule. To determine the degree of oligomerization, gel permeation chromatography (GPC method) and²⁹Si NMR method used. If an oligomer mixture with, for example, 100% by weight, based on well-defined oligomers, is specified here, this information relates to the current detection limit (approx. 1%) of corresponding oligomers using said methods. Oligomers with branched structures can also be present, but are more difficult to reproduce.

0056In order to be able to describe said siloxanes in more detail, so-called M, D and T structures are additionally used in the present application. For the nomenclature of naming such siloxane structures, reference is made to the "Römpp chemistry dictionary" - keyword: silicone.

0057Furthermore, an oligomer mixture of organosiloxanes of component (ii), (iv) or (vi), in particular alkylalkoxysiloxanes, can also be used as empirical formula I.          (R ") Si (OR '' ')_xO_y     (I), reproduce, here preferably groups R "are the same or different and R" is a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, preferably methyl, ethyl, propyl, hexyl, octyl, hexadecyl, especially n-propyl, groups R '' 'are the same or different and R' '' represents a hydrogen or a linear or branched alkyl group with 1 to 4 carbon atoms, preferably methyl, propyl, butyl, especially ethyl, and 1.0 &lt;x &lt;2.0 and 0.5 &lt;y ≤ 1.0 with the proviso (2y + x) = 3.

0058Particularly preferably, an n-propylethoxysiloxane mixture, for example Protectosil® 266, is used in the present invention according to component (ii), (iv) or (vi).

0059In addition, it can be advantageous if an oligomer mixture used according to the invention comprises essentially 70 to 100% by weight, preferably approximately 80 to 99% by weight, in particular approximately 90 to 98% by weight, of alkylalkoxysiloxanes with a degree of oligomerization of 2 to 20 , particularly preferably 2 to 10, in particular 3 to 6, contains. Such oligomer mixtures can also contain corresponding monomeric alkylalkoxysilanes.

0060In particular, said oligomer mixtures of component (ii), (iv) or (vi) may contain the following proportions of alkylalkoxysiloxanes, in particular n-propylethoxysiloxanes, the details being 100% by weight in each case by further components, in particular other alkylalkoxysiloxanes, but possibly also residual amounts of water and / or alcohol of up to ≤ 5% by weight, preferably ≤ 2% by weight, in particular ≤ 1% by weight. -% up to the detection limit, add:<ul id="ul0003" list-style="dash"><li>0 up to 30% by weight, particularly preferably less than 10% by weight, very particularly preferably 0.001 to less than 5% by weight, in particular 0.01 to less than 1% by weight, of alkylalkoxysiloxanes with a degree of oligomerization of n equal to 2, which is an M₂-Have structure,</li><li>8th up to 40% by weight, particularly preferably 10 to 35% by weight, very particularly preferably 15 to 30% by weight, of alkylalkoxysiloxanes which have an M₂D- and / or D₃Have structure, said structures each corresponding to a molar mass of an alkylalkoxysiloxane with degree of oligomerization n equal to 3,</li><li>20 up to 60% by weight, particularly preferably 25 to 55% by weight, very particularly preferably 35 to 50% by weight, in particular 30 to 45% by weight, of alkylalkoxysiloxanes which have an M₂D₂- and / or M₃T and / or D₄Have structure, said structures each corresponding to a molar mass of an alkylalkoxysiloxane with degree of oligomerization n equal to 4,</li><li>5 up to 35% by weight, particularly preferably 8 to 30% by weight, very particularly preferably 15 to 25% by weight, in particular 10 to 24% by weight, of alkylalkoxysiloxanes which have an M₂D₃- and / or M₃DT and / or D₅Have structure, which structures each correspond to a molar mass of an alkylalkoxysiloxane with a degree of oligomerization n equal to 5,</li><li>0.1 to 30% by weight, particularly preferably 0.5 to 25% by weight, very particularly preferably 5 to 20% by weight, of alkylalkoxysiloxanes which have an M₂D₄- and / or M₃D₂T and / or M₄T₂- and / or D₆Have structure, said structures each corresponding to a molar mass of an alkylalkoxysiloxane with a degree of oligomerization of n equal to 6.</li></ul>

0061An oligomer mixture of alkylalkoxysiloxanes containing mixture in the sense of components (ii), (iv) or (vi) of the present invention can, for example - but not exclusively - according to the teaching of <patcit id="pcit0037" dnum="EP1205481A2"><text>EP 1 205 481 A2</text></patcit> getting produced. In addition, a composition mentioned there, including the additives mentioned there, can also be used in the present invention. The disclosure content of the<patcit id="pcit0038" dnum="EP1205481A2"><text>EP 1 205 481 A2</text></patcit> is to be added to the full extent of the present description.

0062An oligomer mixture of alkylalkoxysiloxanes, such as Protectosil® 266, used according to the invention or used to produce the powders may, for example, but not exclusively, have the following physico-chemical properties and the following oligomer distributions:<tables id="tabl0001" num="0001"><table frame="none"><tgroup cols="4" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="25mm" /><colspec colnum="2" colname="col2" colwidth="31mm" /><colspec colnum="3" colname="col3" colwidth="10mm" /><colspec colnum="4" colname="col4" colwidth="21mm" /><tbody><row><entry>Flash point</entry><entry>(EN 22719)</entry><entry>:</entry><entry>> 70 ° C</entry></row><row><entry>viscosity</entry><entry>(20 ° C, DIN 53015)</entry><entry>:</entry><entry>35 mPa s</entry></row><row><entry>density</entry><entry>(20 ° C, DIN 51757)</entry><entry>:</entry><entry>1.04 g / cm³</entry></row><row><entry>Water content</entry><entry /><entry>:</entry><entry>≤0,05 %</entry></row><row><entry>Free alcohol</entry><entry /><entry>:</entry><entry>≤ 0,3 %</entry></row></tbody></tgroup></table></tables><tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="58mm" /><colspec colnum="2" colname="col2" colwidth="28mm" /><thead><row><entry valign="top">Degree of oligomerization (structure types)</entry><entry>Share in% by weight</entry></row></thead><tbody><row><entry>3rd (M₂D, D₃)</entry><entry>25</entry></row><row><entry>4th (M₂D₂, M₃T, D₄)</entry><entry>33</entry></row><row><entry>5 (M₂D₃, M₃DT, D₅)</entry><entry>14</entry></row><row><entry>6 (M₂D₄, M₃D₂T, M₄T₂, D₆)</entry><entry>23</entry></row></tbody></tgroup></table></tables>

0063Said oligomer mixture of alkylalkoxysiloxanes of components (ii), (iv) or (vi) may also be less than 10% by weight, preferably 0 to 8% by weight, particularly preferably 0.001 to less than 5% by weight , of alkylalkoxysiloxanes with a higher degree of oligomerization than 6, the amounts given being based on the oligomer mixture.

0064Furthermore, an oligomer mixture in the sense of component (ii), (iv) or (vi) can contain 0 to less than 5% by weight of alkylalkoxysiloxanes which have a degree of oligomerization of n equal to 7 to 20, the amount being based on the Oligomer mixture is related.

0065It is also suitable if said oligomer mixture of alkylalkoxysiloxanes according to component (ii), (iv) or (vi) contains 0 to less than 1% by weight of alkylalkoxysiloxanes, these having a higher degree of oligomerization than n equal to 20.

0066However, oligomer mixtures of alkylalkoxysiloxanes used according to the invention as component (ii), (iv) or (vi) essentially contain such alkylalkoxysiloxanes with a degree of oligomerization of n equal to 2 to 6, particularly preferably only those with n equal to 3 to 6.

0067In general, it is advantageous if mixtures according to the invention have a low proportion of volatile organic compounds (VOC), which include compounds which have a boiling point at normal pressure of at most 250 ° C. The VOC content, based on the solids content, is preferably less than 2% by weight, preferably less than 0.5% by weight and in particular less than 0.2% by weight.

0068However, it is possible that in addition to an oligomer mixture of alkylalkoxysiloxanes, a mixture also contains small amounts of free alcohol. Such a proportion of free alcohol in the powder can be gradually formed, for example in the presence of comparatively high atmospheric humidity, by hydrolysis of alkoxy groups. The proportions are 0 to less than 5% by weight, preferably less than 2% by weight, very particularly preferably less than 1% by weight, of free alcohol, based on the amount of organosilicon compound in the powder.

0069For the mixtures according to the invention and the mixture for the use according to the invention, it is preferred if the organosilicon compound is insoluble or only water-soluble to a limited extent, an aqueous dispersion, a water-dispersible or redispersible powder. If a readily water-soluble organosilicon compound is used, it is preferably a water-soluble powder. In addition, regardless of the water solubility of the organosilicon compound, the mixture can be a granulated powder in which the water-soluble organic polymer and the organosilicon compound are drawn up and / or adsorbed on an inorganic matrix, care being taken when selecting the inorganic matrix that the drawn up and / or adsorbed compounds simply detach again from the matrix when used according to the invention, to have the effect.

0070It is helpful that the water-soluble organic polymer with the organosilicon compound, insofar as it is insoluble or only sparingly soluble in water, forms a stable dispersion in aqueous solution. It is often advantageous if the compounds are coordinated with one another in such a way that the dispersion obtained still has the same physical properties, such as pH, viscosity, particle size and color, even after 24 hours, and that no separation, ie Settling of dispersion particles occurs. Since different water-soluble organic polymers provide the desired dispersion stability, depending on the type of organosilicon compound, a water-soluble organic polymer may be ideal for certain organosilicon compounds, while incompatibility with other organosilicon compounds may occur. Therefore, the water-soluble organic polymer must be matched to the organosilicon compound. Stabilization systems are preferred which allow the aqueous dispersion composition obtained to be converted in a simple manner by means of drying into powders which are redispersible in water.

0071Typically suitable, water-soluble organic polymers, if not dissolved, are solids and preferably higher molecular weight compounds at room temperature. This includes natural compounds such as polysaccharides, which are optionally chemically modified, synthetic higher molecular weight oligomers and polymers that have no or only a weakly ionic character, and / or polymers that use monomers that are at least partially ionic in character, for example by means of radical polymerization aqueous medium can be prepared in situ. It is also possible for only one water-soluble organic polymer to be used, or for different polymers to be combined with one another. However, it is often helpful if the water-soluble organic polymer has no or only a small proportion of carboxyl groups.

0072Polysaccharides and their derivatives which can preferably be used are cold-water-soluble polysaccharides and polysaccharide ethers, such as cellulose ethers, starch ethers (amylose and / or amylopectin and / or their derivatives), guar ethers and / or dextrins. Synthetic polysaccharides such as anionic, nonionic or cationic heteropolysaccharides, in particular xanthan gum or wellan gum, can also be used. The polysaccharides can, but need not, be chemically modified, for example with carboxymethyl, carboxyethyl, hydroxyethyl, hydroxypropyl, methyl, ethyl, propyl, sulfate, phosphate and / or long-chain alkyl groups. Other natural stabilization systems are alginates, peptides and / or proteins such as gelatin, casein and / or soy protein. Dextrins, starch, starch ether, casein, soy protein, gelatin, hydroxyalkyl cellulose and / or alkyl hydroxyalkyl cellulose are very particularly preferred.

0073Synthetically produced, water-soluble organic polymers can consist of one or more protective colloids, for example one or more polyvinylpyrrolidones and / or polyvinyl acetals with molecular weights from 2000 to 400,000, fully or partially hydrolyzed and / or modified with amino groups, carboxylic acid groups and / or alkyl groups Polyvinyl alcohols with a degree of hydrolysis of preferably approximately 70 to 100 mol%, in particular approximately 80 to 98 mol%, and a Höppler viscosity in 4% aqueous solution of preferably 1 to 50 mPas, in particular of about 3 to 40 mPas (measured at 20 ° C. according to DIN 53015) as well as melamine formaldehyde sulfonates, naphthalene formaldehyde sulfonates, block copolymers of propylene oxide and ethylene oxide, styrene-maleic acid and / or vinyl ether-maleic acid copolymers. Higher molecular weight oligomers can be non-ionic, anionic, cationic and / or amphoteric emulsifiers, such as, for example, alkyl sulfonates, alkylarylsulfonates, alkyl sulfates, sulfates of hydroxylalkanols, alkyl and alkylaryl disulfonates, sulfonated fatty acids, sulfates and phosphates of polyethoxylated alkanols and sulfonates of ester and alkylphenols, as well as esters of ester and alkylphenols, quaternary alkylammonium salts, quaternary alkylphosphonium salts, polyaddition products such as polyalkoxylates, for example adducts of 5 to 50 moles of ethylene oxide and / or propylene oxide per mole of linear and / or branched C.₆- to C₂₂Alkanols, alkylphenols, higher fatty acids, higher fatty acid amines, primary and / or secondary higher alkyl amines, the alkyl group preferably each having a linear and / or branched C.₆- to C₂₂Alkyl group. Synthetic stabilization systems, in particular partially hydrolyzed, optionally modified, polyvinyl alcohols are very particularly preferred, it being possible for one or more polyvinyl alcohols to be used together, if appropriate with small amounts of suitable emulsifiers. Preferred synthetic stabilization systems are in particular modified and / or unmodified polyvinyl alcohols with a degree of hydrolysis of 80 to 98 mol% and a Höppler viscosity as a 4% aqueous solution of 1 to 50 mPas and / or polyvinyl pyrrolidone.

0074It is also possible for a mixture according to the invention to use a plurality of water-soluble organic polymers, for example a combination of one or more natural compounds with one or more synthetically produced compounds.

0075If an aqueous composition according to the invention (also called dispersion or emulsion) or preparation in the sense of the present invention is used, the weight ratio of the organosilicon compound used in each case to the organic polymer can be from about 95: 5 to 5:95, in particular from about 85:15 to 15:85, and preferably from about 70:30 to 30:70, and very particularly preferably from about 60:40 to 40:60, the composition or Preparation advantageously 5 to 95 parts by weight of water, preferably 10 to 70 parts by weight, particularly preferably 15 to 60 parts by weight, very particularly preferably 20 to 50 parts by weight, in particular 25 to 40 parts by weight. Water per 100 parts by weight Contains composition or preparation.

0076If the water-soluble polymer forms a dispersion with the organosilicon compound, its particle size can be adjusted in a targeted manner by the choice of the polymer, the weight ratio of the polymer to the organosilicon compound used, and also by the manner in which they are mixed together. If the mixture is dried to a powder and then dispersed or redispersed again, the original particle size is usually restored. It is often advantageous if the water-dispersed, dispersible or redispersible mixture, when dispersed or redispersed in water, has an average particle size of approximately 0.1 to approximately 50 μm, in particular approximately 0.2 to approximately 30 μm. If the mixture is in powder form, an average particle size of approximately 20 to approximately 500 μm, in particular approximately 50 to approximately 250 μm, has proven to be advantageous. However, it can also lie outside this range, whereby larger particles are often more suitable than smaller ones, which are more prone to dusting.

0077The particle size can be determined using the customary measurement methods, the light scattering method preferably being used and the particle size being stated as the volume average.

0078The water-dispersible or redispersible mixture, when dispersed or redispersed in water, advantageously has a solids content of approximately 5 to 75% by weight, in particular approximately 15 to 65% by weight, and very particularly preferably approximately 30 to 50% by weight. -% and typically has a viscosity of about 100 to 100,000 mPas, preferably about 200 to 25,000 mPas, in particular about 300 to 10,000 mPas, and very preferably about 500 to 5,000 mPas, measured according to DIN 53 015 .

0079The mixtures according to the invention or mixtures for the use according to the invention can also contain further additives. There are no limits to the type of other additives. As a rule, they have an important function in the use of the powder according to the invention, but this is not mandatory. Further water-soluble organic polymers can also be added, in which case they are preferably added in powder form.

0080The content of the additives, based on the sum of the water-soluble organic polymer and the organosilicon compound, is not subject to any significant limits. For example, the content of surface-active substances can be very small and be in the range of about 0.01% by weight or more, in particular about 0.1% by weight or more and preferably about 1% by weight or more on the solids content of the mixture. On the other hand, much larger proportions of additives can also be added to the mixtures according to the invention, such as fillers or dispersions and / or dispersion powders based on emulsion and / or suspension polymers containing, for example, copolymers based on vinyl acetate, ethylene-vinyl acetate, ethylene-vinyl acetate -Vinyl versatate, ethylene-vinyl acetate- (meth) acrylate, ethylene-vinyl acetate-vinyl chloride, vinyl acetate-vinyl versatate, Vinyl acetate-vinyl versatate (meth) acrylate, vinyl versatate (meth) acrylate, pure (meth) acrylate, styrene-acrylate and / or styrene-butadiene. In this case, up to about 1000 parts, in particular up to about 500 parts and preferably up to about 100 parts of additives can be added to one part of the material according to the invention.

0081Preferred additives are in particular water repellents, such as fatty acids and their salts and esters, fatty alcohols, silanes, air entraining agents, wetting agents, defoamers, emulsifiers, film-forming aids, setting and setting accelerators, setting retarders, thickeners, dispersants, rheology control additives. such as cement plasticizers, polycarboxylates, polycarboxylate ethers, polyacrylamides and / or thickeners, corrosion inhibitors, such as alkylammonium benzoates, amino alcohols, gluconic acid and / or their alkali and alkaline earth metal salts, water retention agents, cellulose fibers and cellulose ethers, starch ethers, guar ethers and additives for reducing sedimentation and additives to reduce sedimentation. or floating, fillers, and if the mixture is powdery, Additives to reduce powder blocking and / or film-forming, water-insoluble dispersion powders and, if the mixture is liquid, film-forming polymer dispersions.

0082Furthermore, powdery and / or liquid defoamers, wetting agents, alkyl, hydroxyalkyl and / or alkylhydroxyalkyl polysaccharide ethers such as cellulose ethers, starch ethers and / or guar ethers can be used as additives, the alkyl and hydroxyalkyl group typically having a C.₁- to C₄- Group is synthetic polysaccharides, such as anionic, nonionic or cationic heteropolysaccharides, in particular xanthan gum or wellan gum, cellulose fibers, dispersants, cement plasticizers, setting accelerators, solidification accelerators, setting retarders, air entraining agents, polycarboxylates and polyacrylate, partial or polyamide, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, partially, and polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, partially, and polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, partially, and polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate, polycarboxylate and polycarboxylate, partially polycarboxylate, polycarboxylate, or polycarboxylate, polycarboxylate, polycarboxylate, or polycarboxylate, partially polycarboxylate, polycarboxylate, polycarboxylate, or polycarboxylate, partially optionally modified, polyvinyl alcohols, polyvinyl pyrrolidones, polyalkylene oxides and polyalkylene glycols, the alkylene group typically being a C₂- and / or C₃Group, which also includes block copolymers, contains dispersions and dispersible polymer copolymers, for example based on vinyl acetate, ethylene-vinyl acetate, ethylene-vinyl acetate-vinyl versatate, ethylene-vinyl acetate (meth) acrylate, ethylene-vinyl acetate-vinyl chloride, vinyl acetate-vinyl versatate , Vinyl acetate-vinyl versatate (meth) acrylate, vinyl versatate (meth) acrylate, pure (meth) acrylate, styrene-acrylate and / or styrene-butadiene, water repellents, such as silanes, silane esters, siloxanes, Silicones, fatty acids and / or fatty acid esters, thickeners, fillers such as quartzitic and / or carbonate sands and / or flours such as quartz sand and / or limestone powder, carbonates, silicates, layered silicates, precipitated silicas, light fillers such as hollow glass spheres made of glass, polymers such as polystyrene spheres, Aluminum silicates, silicon oxide, aluminum silicon oxide, calcium silicate hydrate, silicon dioxide, aluminum silicate, magnesium silicate, aluminum silicate hydrate, Calcium aluminum silicate, calcium silicate hydrate, aluminum iron magnesium silicate, calcium metasilicate and / or volcanic slag as well as puzzolans such as metakaolin and / or latent hydraulic components are added. Very particularly preferred additives are polymer dispersions, dispersion powders, polysaccharide ethers, plasticizers and water repellents, in particular silanes, silane esters, fatty acids and / or fatty acid esters.

0083The present invention also relates to a process for the preparation of mixtures according to the invention by<ul id="ul0004" list-style="dash" compact="compact"><li>in a first step at least 10% by weight of at least one organic polymer according to (i), (iii) or (v), based on the total amount of organosilicon compounds, with at least one organosilicon compound according to (ii), (iv) or ( vi) mixed, optionally adding the remaining amount of organic polymer during and / or after dispersing, optionally adding further additives before, during and / or after dispersing and</li><li>in a second step, the dispersion obtained in the first step dries, further additives being able to be added during and / or after drying.</li></ul>

0084The mixtures according to the invention are produced by a method according to the invention in which in a first step at least 10% by weight, preferably at least 20% by weight, of the organic water-soluble polymer, based on the total amount of organosilicon compound, is mixed with the organosilicon compound. This step is usually carried out in water, the organic polymer being dissolved in water beforehand. Any remaining amount of organic polymer is added during and / or after dispersing or emulsifying. It is often advantageous if the mixing is carried out with stirring, generally higher shear forces are preferred. This process step can be carried out batchwise, continuously, for example via static mixers, or semi-continuously both at room temperature and at elevated temperature. In the first step of the process according to the invention, the present starting materials can be stirred, dispersed and emulsified in order to be able to provide a composition as the basis for the second process step.

0085In another preferred embodiment, the organosilicon compound is previously dispersed using nonionic, cationic and / or anionic emulsifiers, the dispersion obtained then being mixed with the organic water-soluble polymer.

0086Additional additives can be added before, during and / or after dispersing, it being helpful if a pH buffer such as sodium carbonate or sodium bicarbonate is also added to the aqueous phase. Other suitable additives are, for example, defoamers and / or wetting agents, low molecular weight polyalkylene glycols, fatty acids and / or fatty acid derivatives.

0087If the organosilicon compound has a slightly increased viscosity, so that exact dosing is difficult at room temperature, it can also be heated to simplify dosing and dispersion. Alternatively, a diluent can also be added to the organosilicon compound beforehand in order to adjust the viscosity, it often being preferred if this diluent is subsequently removed again, for example by distillation. A low-viscosity organosilicon compound, which does not have to be removed, can also be used as the diluent.

0088The dispersion obtained is usually subsequently dried, with further additives being able to be added during and / or after the drying, the drying preferably being carried out by means of spray drying, freeze drying, fluid bed drying, drum drying, granulation or rapid drying, and wherein spray drying is particularly preferred, and that Spraying can take place, for example, using a spray wheel, single or multi-component nozzle. It is often helpful if, during and / or after drying, antiblocking agents and / or fillers such as aluminum silicates, colloidal silicon dioxide gel, pyrogenic silicon dioxide, ground clays, perlites, vermiculites, light spar, talc, cements, chalk powder, calcium / magnesium mixed carbonates and / or diatomaceous earth may be added.

0089If necessary, the aqueous dispersion can also be diluted with water in order to obtain a viscosity suitable for drying. There are basically no significant limits to the drying temperature. For safety reasons in particular, however, it should generally not exceed approximately 200 ° C., in particular approximately 180 ° C. In order to achieve sufficiently efficient drying, temperatures of approximately 110 ° C. or higher, in particular approximately 120 ° C. or higher, are preferred. The outlet temperature of the gas stream formed during drying is generally about 40 ° C to 100 ° C, in particular about 50 ° C to 90 ° C.

0090The process according to the invention can further include the addition of further additives, the said additives depending on the type and / or process engineering possibilities, for example initially mixed with the organic component and / or with the water-soluble organic polymeric protective colloid, added to the aqueous dispersion obtained and / or as Powder can be added to the powder obtained during and / or after drying. Liquid additives can also be sprayed onto the powder during or after drying. The liquid and / or water-soluble additives are preferably added before, during or after dispersing, and powdery additives are preferably mixed with the powder obtained during or after drying.

0091If another dispersion is also to be dried, it is possible to mix the dispersions to be dried with one another and to spray and dry them together, to spray them separately at the same time via a two-component or multi-component nozzle and then to dry them simultaneously, or else spray both dispersions separately and then mix the powders obtained together.

0092The mixtures according to the invention are used in particular in and on compositions which contain at least one mineral binder, in particular a hydraulically setting binder. Furthermore, they are used to protect metal, building materials, building blocks, components and / or structures from corrosion, the metal in question being generally surrounded by mineral building materials. In addition, the mixtures according to the invention are also suitable for hydrophobicizing such compositions and also for consolidating stones.

0093The compositions containing at least one mineral binder are preferably concrete, in particular reinforced concrete, expanded concrete, gas concrete, fiber concrete, steel fiber concrete, aerated concrete, shotcrete, underwater concrete, rolled concrete, centrifugal concrete, vacuum concrete, self-compacting concrete (SCC), screed concrete, split concrete, drain concrete, foam concrete, Prefabricated components made of concrete high-strength and ultra-high-strength concrete and / or glass foam concrete, brick, terracotta, plasters such as gypsum and / or lime and / or cement plasters, mortar, in particular dry mortars, such as repair and full heat protection mortar, joint and tile adhesives, plywood mortar, mortar for adhesive bridges, cementitious parquet adhesives, cement primers, leveling and / or leveling compounds, sealing slurries, powder paints and concrete coatings, such as slurries for coating the steel or for repair of reinforced concrete during concrete renovation.

0094The mixtures according to the invention can be applied to any substrates in order to protect them from corrosion. Non-limiting examples of such substrates are mineral building materials, building blocks, components and / or structures, in particular if they come into contact with metal, envelop or enclose metal, mineral building materials such as concrete, sand-lime brick, granite, lime, plaster, marble, pearlite, clinker , porous tiles and tiles, natural stone, screed, clay articles but also artificial stone, masonry, facades, roofs and structures such as bridges, port facilities, residential buildings, Industrial buildings and publicly used buildings, such as parking garages, train stations or schools, but also prefabricated parts, such as railway sleepers and / or L-stones.

0095Likewise, the mixtures according to the invention can be used as agents or in preparations for stone consolidation and as agents or in preparations for waterproofing and for protection from damage by water.

0096The mixtures according to the invention can also be used for coating cables, in particular for insulating cables and / or for hydrophobizing cable surfaces.

0097The present invention also relates to preparations or compositions comprising the mixtures according to the invention, in particular those which contain or are based on at least one mixture according to the invention or at least one mixture according to the invention and water. The mixture is usually in a concentration between 0.01 to 25 wt .-%, in particular about 0.1 to 10 wt .-%, and preferably at about 0.2 to 5 wt .-%, based on the Dryness of the preparation or agent used, taking care that any standard regulations are observed.

0098Preparations or agents according to the invention are, for example, but not exclusively, repair mortar, cement-based sealing compounds, jointing compounds, concrete, in particular reinforced concrete, expanded concrete, gas concrete, fiber concrete, reinforced steel fiber concrete, aerated concrete, shotcrete, underwater concrete, rolled concrete, centrifugal concrete, vacuum concrete, self-compacting concrete (SCC), E-concrete , Split concrete, drain concrete, high-strength and ultra-high-strength concrete, glass foam concrete, terracotta, gypsum and / or lime and / or cement plasters, Repair and full heat protection mortar, joint and tile adhesives, leveling and leveling compounds, sealing slurries, powder paints and concrete paints, but also aqueous dispersions or solutions containing the mixture.

0099Therefore, the subject of advantageous substrates according to the invention, ie building materials, building blocks, components or structures based on a preparation according to the invention, an agent according to the invention or a mixture according to the invention.

0100Articles based on a substrate according to the invention also form part of the subject matter of the invention. Examples are articles made from prefabricated concrete parts according to the invention, such as prefabricated houses, tunnels, bridges, streets, house facades and containers

0101Another object of the present invention is therefore also a mixture which can be obtained by the process according to the invention.

0102The mixtures according to the invention, if they are in powder form, are surprisingly distinguished by particularly good handling, storage stability with good flow properties, as a result of which they can be metered well into other formulations which can be liquid, pasty or powdery in nature.

0103Furthermore, the mixtures used according to the invention and the mixtures according to the invention surprisingly show excellent dispersing, redispersing or dissolving behavior in water and very good wettability, as a result of which they can be very easily stirred into the compositions. If the mixture is in powder form, it can ideally be dispersed, redispersed or dissolved within a few seconds upon contact with water, if necessary by stirring gently. In certain cases it is also possible that somewhat stronger shear forces are necessary. In any case, the shear forces that occur during normal mixing processes of dry mortars are generally sufficient to completely disperse or redisperse the powder according to the invention, as a result of which the particle size of the aqueous dispersion before drying and a homogeneous distribution in the mass is achieved.

0104Although in the mixtures according to the invention the generally liquid organosilicon compound is enclosed by the water-soluble organic polymer in such a way that the organosilicon compound remains encapsulated even during and after a drying step, it has surprisingly been found that this, when used together with the mineral binder and water, has its effect can fully unfold. In addition, the water-soluble organic polymer generally does not interfere during or after the production of the building materials and for the further properties of the fresh concrete / fresh mortar or for the hardened system. On the contrary, it even advantageously has very good processability, wettability, good dispersibility and / or redispersibility. In addition, the water-soluble polymer can also act as a binder, which increases the physical strength of the set building materials.

0105The mixtures according to the invention are thus advantageously also distinguished by a particularly uniform distribution and, in an outstanding manner, have a particularly corrosion-inhibiting action in the building structure and good stability to alkali in the building material. In addition, harmful chloride ions and other pollutants dissolved in water, such as. B. sulfates, which can lead to ettringite formation, kept away from the building material. For this reason, they are particularly well suited for the production of a wide variety of structures and for the repair and restoration of structures or components. When using such mixtures in mineral-setting compositions, corrosion protection, which is significantly better than that available on the market, of both the steel and Metal reinforcements as well as building blocks or structures is obtained.

0106In addition, it is particularly surprising that, in addition to the usual hydrophobizing effect when using silane products with a hydrophobic effect, the use of a mixture according to the invention in particular significantly improves the corrosion properties of building blocks, components or structures and corresponding steel or metal reinforcements - also compared to conventional corrosion protection measures could become.

0107The present invention is explained in more detail by the following examples, without restricting the subject matter.

<u style="single">Examples</u>

<u style="single">example 1</u>

Production of powder 1

0108100 g Protectosil^® 266 were in 329.2 g of a 24 wt .-% aqueous solution of a polyvinyl alcohol with a degree of saponification of 88 mol% and a Höppler viscosity as a 4% solution of 4 mPas with a propeller at 1000 rpm for 15 minutes emulsified and then diluted with water to a solids content of 25% by weight. This mixture was sprayed on a laboratory spray tower with a two-component nozzle using compressed air at an inlet temperature of 120 ° C. and dried. 0.6% by weight of a pyrogenic silica and 9.4% by weight of a commercially available carbonate, based on the finished powder, were added as anti-caking agents. A free-flowing white powder which was readily redispersible in water was obtained in good yield and does not become greasy even when rubbed between the fingers and thus contains the propylalkoxysiloxane mixture used in a well-encapsulated form.

<u style="single">Example 2</u>

Production of powder 2

0109Example 1 was repeated, the mixture prepared not being diluted with water. The solids content was 37.9% by weight and the Brookfield viscosity, measured with spindle 3 at 20 rpm and 25 ° C., 1,590 mPas. Spray drying was carried out using an atomizing disc at an inlet temperature of 150 ° C. A free-flowing, readily wettable and readily redispersible white powder was obtained in good yield and, when mixed with water, disintegrates into the primary particles within a short time.

<u style="single">Example 3</u>

Production of powder 3

0110200.0 g of a 50% by weight aqueous emulsifier-stabilized emulsion from Protectosil® 266 were mixed with 329.2 g of a 24% by weight aqueous solution of a polyvinyl alcohol with a degree of saponification of 88 mol% and a Höppler viscosity of 4 % solution of 4 mPa s mixed as in Example 2, diluted, dried and mixed with an anti-caking agent. A free-flowing, readily wettable and readily redispersible white powder was obtained which does not become greasy even when rubbed between the fingers and thus contains the siloxane used in a well-encapsulated form.

<u style="single">Example 4</u>

Production of powder 4

011140 g of a liquid silane based on isobutyltriethoxysilane were dissolved in 595.7 g of a 24% by weight aqueous solution of a polyvinyl alcohol with a degree of saponification of 88 mol% and a Höppler viscosity as a 4% solution of 4 mPas with a propeller stirrer at 1 000 rpm emulsified for 15 minutes and then diluted with water to a solids content of 25% by weight. This mixture was sprayed on a laboratory spray tower with a two-component nozzle using compressed air at an inlet temperature of 120 ° C. and dried. 0.6% by weight of a pyrogenic silica and 9.4% by weight of a commercially available carbonate, based on the finished powder, were added as anti-caking agents. A free-flowing, readily wettable and readily redispersible white powder was obtained in good yield, which does not become greasy even when rubbed between the fingers and thus contains the silane preparation used in a well-encapsulated form.

<u style="single">Example 5</u>

0112<b>Production of powders 5 to 10 according to</b><patcit id="pcit0039" dnum="EP0228657A"><text>EP 0 228 657</text></patcit><b>:</b>

0113Analogous to that in <patcit id="pcit0040" dnum="EP0228657A"><text>EP 0 228 657</text></patcit> The examples described were the corresponding polysiloxanes or silanes, cf. Table 1, dispersed or emulsified in aqueous polyvinyl alcohol solution (24.3% by weight solution of a polyvinyl alcohol with a degree of saponification of 88 mol% and a Höppler viscosity as a 4% solution of 4 mPa s) and with water to 40 % By weight non-aqueous portion diluted. The stability of the spray batches was assessed after 2 and 12 h. Table 3 shows the resulting supernatant in cm as a stability criterion. After prior stirring, the spray batches were then sprayed and dried in a laboratory spray dryer (inlet temperature 135 ° C., outlet temperature 76 ° C.) using a two-component nozzle (air pressure 3.5 bar).<tables id="tabl0003" num="0003"><table frame="all"><title>Table 1 :</title><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="33mm" /><colspec colnum="2" colname="col2" colwidth="14mm" /><colspec colnum="3" colname="col3" colwidth="17mm" /><colspec colnum="4" colname="col4" colwidth="24mm" /><colspec colnum="5" colname="col5" colwidth="13mm" /><colspec colnum="6" colname="col6" colwidth="13mm" /><colspec colnum="7" colname="col7" colwidth="13mm" /><thead><row><entry valign="top">Example No.</entry><entry align="center" valign="top">5a</entry><entry align="center" valign="top">5b</entry><entry align="center" valign="top">5c</entry><entry align="center" valign="top">5d</entry><entry align="center" valign="top">5e</entry><entry align="center" valign="top">5f</entry></row><row><entry valign="top">Powder no.</entry><entry align="center" valign="top">5</entry><entry align="center" valign="top">6</entry><entry align="center" valign="top">7</entry><entry align="center" valign="top">8</entry><entry align="center" valign="top">9</entry><entry align="center" valign="top">10</entry></row></thead><tbody><row><entry>Ex <patcit id="pcit0041" dnum="ep228657a"><text>EP228657</text></patcit></entry><entry align="center">3^a)</entry><entry align="center">1^a)</entry><entry align="center">5^a)</entry><entry align="center">7^a)</entry><entry align="center">11</entry><entry align="center">10</entry></row><row><entry>Siloxane content</entry><entry align="center">80 %</entry><entry align="center">90 %</entry><entry align="center">95 %</entry><entry align="center">90 %</entry><entry align="center">90 %</entry><entry align="center">90 %</entry></row><row><entry>PVOH portion</entry><entry align="center">20 %</entry><entry align="center">10 %</entry><entry align="center">5 %</entry><entry align="center">10 %</entry><entry align="center">10 %</entry><entry align="center">10 %</entry></row><row><entry rowsep="0">Stability after</entry><entry rowsep="0" align="center" /><entry rowsep="0" align="center" /><entry rowsep="0" align="center" /><entry rowsep="0" align="center" /><entry rowsep="0" align="center" /><entry rowsep="0" align="center" /></row><row rowsep="0"><entry>2nd H</entry><entry align="center">0</entry><entry align="center">0.1</entry><entry align="center">1.5</entry><entry align="center">0</entry><entry align="center">0</entry><entry align="center">0</entry></row><row><entry>12th H</entry><entry align="center">0</entry><entry align="center">1.0</entry><entry align="center">3.5</entry><entry align="center">0.5</entry><entry align="center">0.1</entry><entry align="center">0.5</entry></row><row><entry>yield</entry><entry align="center">moderate</entry><entry align="center">bad</entry><entry align="center">very bad</entry><entry align="center">N / A^b)</entry><entry align="center">N / A^b)</entry><entry align="center">N / A^b)</entry></row></tbody></tgroup><tgroup cols="7" rowsep="0"><colspec colnum="1" colname="col1" colwidth="33mm" /><colspec colnum="2" colname="col2" colwidth="14mm" /><colspec colnum="3" colname="col3" colwidth="17mm" /><colspec colnum="4" colname="col4" colwidth="24mm" /><colspec colnum="5" colname="col5" colwidth="13mm" /><colspec colnum="6" colname="col6" colwidth="13mm" /><colspec colnum="7" colname="col7" colwidth="13mm" /><tbody><row><entry namest="col1" nameend="col7" align="justify">a) The corresponding propylsiloxane was used instead of the methylsiloxane b) Because of the poor yield of powders 5-7, these mixtures were not sprayed.</entry></row></tbody></tgroup></table></tables>

0114The spray batches were not stable with 20% polyvinyl alcohol except for example 5a and were therefore stirred before spray drying. Because of the poor sprayability, only Examples 5a-5c were dried. The yields decrease drastically with decreasing PVOH content and an increasingly greasy wall covering is obtained in the spray tower. The powders are also greasy when rubbed between the fingers, which shows that the polysiloxane is not properly encapsulated.

0115According to the teaching of <patcit id="pcit0042" dnum="EP0228657A"><text>EP 0 228 657</text></patcit> Spray batches and powders produced clearly show that their properties are not very advantageous with regard to spray batch stability and sprayability. In addition, they show a very poor wettability and a very slow redispersibility, which makes it significantly more difficult to use in building materials. Thus, powders based on these compositions have to be produced in a more complex process. However, if the production process and any additives additionally added are chosen such that the powders obtained meet the requirements with regard to storage stability, wettability and redispersibility, such compositions can also be used for the inventive use.

<u style="single">Example 6</u>

Application studies - Determination of the water absorption coefficient of a cement / sand mortar

0116The water absorption coefficient was determined after 24 hours in accordance with DIN 52617 to assess the corrosion-inhibiting and, if appropriate, hydrophobizing effect of the powders in comparison with the liquid starting material. A mortar base mixture consisting of 25% by weight of Portland cement CEM I 42.5 N and 75% by weight of standard sand in accordance with DIN EN 196-1 was mixed with the active ingredient given in Table 2 and with 12% by weight of water, based on the dry formulation, mixed with a 60 mm propeller stirrer at a speed of 950 rpm for 60 seconds. After a maturation time of 3 minutes, the mortar was briefly stirred again by hand, then poured into plastic ring molds with a diameter of 8 cm and a height of 2 cm and the surface was removed with a spatula at the level of the mold. The test specimens were stored at 23 ° C. and 50% relative atmospheric humidity for 14 days, whereby they were switched off after the first day. After weighing the test specimens, they were stored in water for 24 hours and then weighed again after the water adhering to the surface had dried. The water absorption coefficient ω was then determined from the weight difference, the surface of the test specimens and the duration of the water storage in accordance with DIN 52617₂₄ calculated. The tests were carried out with a liquid active ingredient containing silane and also with the powders used according to the invention. No significant change in the setting behavior was observed.

<u style="single">Table 2</u>

0117Water absorption coefficient ω₂₄ of powder 3 and 1 compared to liquid active ingredient without PVOH in a cement / sand mortar after a 24 hour soak. The water absorption coefficient was determined in accordance with DIN 52617 and is in [kg / m²*H^0.5] specified. The metered amount was adjusted so that the amount of active ingredient, based on the amount of silane or siloxane, was 1.8% by weight, based on the dry proportion of the mortar mixture used.<tables id="tabl0004" num="0004"><table frame="all"><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="35mm" /><colspec colnum="2" colname="col2" colwidth="27mm" /><colspec colnum="3" colname="col3" colwidth="27mm" /><thead><row><entry morerows="1" valign="top">Active ingredient from example</entry><entry namest="col2" nameend="col3" align="left" valign="top"><b>Water absorption coefficient ω₂₄</b></entry></row><row><entry valign="top"><b>Liquid</b></entry><entry valign="top"><b>powder</b></entry></row></thead><tbody><row><entry>3</entry><entry align="char" char=".">0.031</entry><entry align="char" char="." charoff="7">0.049</entry></row><row><entry>1</entry><entry align="char" char=".">0.025</entry><entry align="char" char="." charoff="7">0.031</entry></row></tbody></tgroup></table></tables>

0118With powder 2, the water absorption coefficient was determined as described above, but using a mortar with a mortar base mixture consisting of 34% by weight Portland cement CEM I 42.5, 59.8% by weight quartz sand 0.1 to 0.5 mm, 3% by weight % Hydrated lime, 0.2% by weight of cellulose ether Tylose MH 10007 P4 and 3% by weight of a redispersion powder based on an ethylene-vinyl acetate copolymer, which was mixed with 22% by weight of water.

<u style="single">Table 3</u>

0119Water absorption coefficient ω₂₄ of powder 2 in the mortar (see text) after a 24 hour soak. The water absorption coefficient was determined in accordance with DIN 52617 and is in [kg / m^2*H^0.5] specified.<tables id="tabl0005" num="0005"><table frame="all"><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="33mm" /><colspec colnum="2" colname="col2" colwidth="53mm" /><thead><row><entry valign="top" /><entry valign="top"><b>Water absorption coefficient ω₂₄</b></entry></row></thead><tbody><row><entry>without additive</entry><entry align="char" char="." charoff="4">0.269</entry></row><row><entry>0.5% by weight powder 2</entry><entry align="char" char="." charoff="4">0.196</entry></row></tbody></tgroup></table></tables>

0120The results from Table 2 clearly show that the polyvinyl alcohol used for spraying has no significant influence on the water absorption of the hardened mortar, and thus on the water absorption coefficient. In addition, the values ​​from Table 3 show that even the smallest amounts of the inventive powder bring about a significant reduction in water absorption. This also reduces the chloride penetration in water containing chloride, which further makes possible steel corrosion impossible, or at least significantly delays it.

<u style="single">Example 7</u>

Determination of the corrosion-inhibiting effect of powders using laboratory tests

0121The aim of the investigation was to quantify the inhibitor effectiveness in laboratory tests. The use of standard methods (e.g. testing according to ASTM) is not possible in this case, since specific properties, especially of powders based on silicon compounds, do not, or only to a small extent, come into play. The effect of cyclic weathering with dry and wet periods was therefore investigated in the laboratory. Under these circumstances, the concrete can dry out and affect corrosion. The use of prefabricated concrete cubes with a side length of 15 cm, each equipped with three sensors for monitoring the rate of corrosion and the state of corrosion, enables the continuous recording of the corrosion behavior. The concrete formulation used and the manufacturing conditions are summarized in Tables 2 to 3. The test specimen for carrying out the corrosion tests is shown schematically in <figref idref="f0001">Fig. 1</figref> shown.<tables id="tabl0006" num="0006"><table frame="all"><title><b><u style="single">Table 4</u></b></title><tgroup cols="6"><colspec colnum="1" colname="col1" colwidth="46mm" /><colspec colnum="2" colname="col2" colwidth="27mm" /><colspec colnum="3" colname="col3" colwidth="27mm" /><colspec colnum="4" colname="col4" colwidth="18mm" /><colspec colnum="5" colname="col5" colwidth="18mm" /><colspec colnum="6" colname="col6" colwidth="18mm" /><thead><row><entry namest="col1" nameend="col6" colsep="0" align="left" valign="top"><b>Formulation of the concrete used using Portland cement CEM I.</b></entry></row><row><entry valign="top">Recipe</entry><entry morerows="1" valign="top">Water [kg / m3]</entry><entry morerows="1" valign="top">Cement [kg / m3]</entry><entry namest="col4" nameend="col6" align="left" valign="top">Surcharge [kg / m3]</entry></row><row><entry rowsep="0" valign="top">Concrete W / Z 0.6 largest grain ⌀ 16</entry><entry valign="top">0 - 4 mm</entry><entry valign="top">4th - 8 mm</entry><entry valign="top">8th - 16 mm</entry></row></thead><tbody><row><entry /><entry>210</entry><entry>350</entry><entry>895</entry><entry>358</entry><entry>537</entry></row></tbody></tgroup></table></tables>

0122Three reinforcement bars with a diameter of 8 mm and a length of 45 mm were installed as sensors. Their concrete coverage was 10 mm, 28 mm and 46 mm. For the measurement of the corrosion current, these sensors were connected to one cathode each (in<figref idref="f0001">Fig. 1</figref> only one cathode is shown). The weathering, which occurs during the course of seasonal stresses, was simulated by wet / dry cycles with 5 days at 35 ° C and 2 days immersion in electrolyte solution. The wet / dry cycles carried out as part of the tests usually only occur once or twice a year in buildings. The penetration of chlorides can therefore be simulated under these test conditions in a greatly accelerated form (2 weeks would correspond to approx. 1 year here). 2 different test specimens were produced with powder 1 from example 1. The test specimens P1 and P2 were produced with a powder content of 2% (P1) and 4% (P2), based on the cement content, using the concrete composition from Table 4. The amount of powder used corresponds to an active ingredient content, based on the organosilicon compound, of 1% by weight or 2% by weight. The test specimens were switched off after 4 days and then stored at 100% relative atmospheric humidity at room temperature for 7½ weeks. The cyclic treatment of the samples was then started, the samples being immersed in 1 M aqueous NaCl solution. In <figref idref="f0002">Fig.2a and 2b</figref> the corrosion current profiles of these test specimens are shown on the sensors with a 10 mm coverage of the bodies P1 (with 2% by weight of powder 1) and P2 (with 4% by weight of powder 1). The test specimen P2 shows no corrosion. In contrast, the activation of corrosion was observed on the reference body P1 on the lowest reinforcement layer (10 mm). The body P1 shows a certain reduction in the rate of corrosion over time, which could be attributed to a certain inhibitory effect. On the basis of the available data, however, a powder concentration of 2% by weight must be assessed as too low for an effective corrosion protection effect. An active ingredient concentration of the silicon compound of about 2% by weight (with 4% by weight of powder 1), based on the cement content, clearly has a corrosion-inhibiting effect.