WO1981001703A1

WO1981001703A1 - Process for the preparation of a mortar and the product thereby obtained

Info

Publication number: WO1981001703A1
Application number: PCT/SE1980/000335
Authority: WO
Inventors: J Puehringer
Original assignee: J Puehringer
Priority date: 1979-12-17
Filing date: 1980-12-16
Publication date: 1981-06-25
Also published as: JPS58500061A; EP0047746A1

Abstract

A process for the preparation and modification of hardened mortars, a wet mortar being prepared in accordance with conventional technique, said wet mortar consisting of or containing one or several hydraulic binders, filler and ballast material, the major part being mineral material, water and additives, comprising adding to the mortar or its solid components at some stage or at different stages during the process of its manufacture alkoxy silanes and/or their condensation products and/or their hydrolysis products, optionally together with an aliphatic or aromatic solvent, optionally with tensides/surfactants/ emulsifiers, optionally with (silanol) polymerization/condensation catalysts.

Description

PROCESSFORTHEPREPARATIONOFAMORTARANDTHE PRODUCTTHEREBYOBTAINED

The purpose of the present invention is to improve properties and functions of mortars (i.e. materials prepared from one or some hydraulic binders and mainly mineral ballast material having a grain size from the 5 filler range up to some centimeters), for example by lowering the capacity of water take up in the micro pore system, lowering the reduction of strength when adding a hydrophobating agent or even improve strength by a process for modifying hardened mortars for the

10 purpose of providing polysiloxane particles or films or silica gel in the hardened mortar by adding alkoxy silanes in combination with other particular active substances at some stage of the process of manufacturing the wet mortar.

15 Methods of manufacturing dry mortars, wet mortars and hardened mortars of ballast, additives, water and hydraulic binders are known. An accepted way of manufacturing a hardened mortar resides in adding pulverulent substances, such as lime, cement (and

20 gypsum) or mixtures thereof and water to mixtures of granular and fibre-formed synthetic and preferably natural inorganic materials of mineral types. Materials prepared in this manner are inter alia lime, lime-ce¬ ment and cement mortars (ordinary and finishing mortars)

25 and all conventional types of concrete. Another method of preparing mortars resides in using additives to change above all the physical/mechanical properties of such mortars.

An increase of the pore volume can also be ob-

__>0 tained by admixing air or adding blowing agents.

Yet another manner to prepare -mortars with hydraulic binders is to subject the plastic mortar to high temperatures and high pressures.

Now, it is an object of the invention to improve the properties of materials prepared from mineral binders, reactive or/and non-reactive ballast and water with conventional additives. Among such materials the following may be mentioned:

Ordinary , _^

/and finishing mortars are prepared from lime, cement, mineral ballast, water, pigments and convention al additives for different purposes. Concrete mortar is made from different types of cement, mainly Portland cement, slag cement, mineral ballast and water and with conventional additives. Particular types of mortars are light concrete and lime sand bricks. These types of mortars are at some stage during the process of manufacture treated with high temperatures under relatively high pressures for longer periods of time. The last-mentioned products are steam hardened in autoclaves.

The disadvantages of the known hydrophobation technique is the fact that on the one hand the hydro- phobating agents are not alkali resistant or so only to a limited extent, on the other hand that their addition results in uncontrolled formation of air pores with concomittant reduction of strength, and they also require a longer mixing time. Air pore formation is inter alia the purpose or the result of the examples described in German patent specifications 1 171 729 and 1 201 22 , wherein alkoxy silanes are added directly to the concrete. All these disadvantages are reduced or wholly prevented by using the process of the invention, namely adding silanes and preferably alkoxy silanes, either in the form of primarily alkylalkoxy silanes or/and tetraalkoxy silanes or phenylalkoxy silanes to the mortar. From Swedish lay-open print 76-13507-8 it is known ^_ ^Q to prepare emulsions consisting of alkyl alkoxysilanes, tensides/emulsi iers/surfactants, water and optionally alcohol,- . Such emulsions are according to said patent specification used in a process for imparting to the surface of final constructional elements consisting of hardened mortar certain waterrepellancy/hydrophobicity. Emulsions according to said patent specification can be made in different ways. As an active hydrophobating agent Uaere is used alkyl alkoxysilanes and condensation and hydrolysis products obtained therefrom with a criterion that they shall be soluble in lower alcohols, such as methanol, ethanol and propanol. It has now been surprisingly found that emulsions prepared in this manner not only can be used for hydrophobating the surface of already hardened mortars but may also be used as additives during one stage or some stages in the process for preparing the mortar. It has been surprisingly found that it is possible to add said emulsions or above all to provide said emulsions directly in the mortar at some stage during the process for its manufacture thereby to give the mortar hydrophobic properties at the same time as reduction of strength due to the addition of sur¬ factants is reduced or avoided or even that improvement of strength can be provided. In said lay-open print 76-13507-8 there are described silanes and /or their condensation products and/or hydrolysis products, preferably alkyltrialkoxy silanes and their condensation products with 0-2 alkoxy groups per silicon atom. According to a variant of said process the alkoxy residue of the silane may be consti¬ tuted by a methoxy or ethoxy residue and the alkyl residue of the alkyl alkoxysilane can have 1-6 carbon atoms. It has now been found according to the invention that the positive effects of the admixture of the silane with the mortar according to the invention are not limited to such alkyl trialkoxysilanes and their condensation products but are obtained also with other alkoxysilanes, such as for example alkyl alkoxysilanes in general and in a similar manner phenyl alkoxysilanes and also alkoxysilanes having functional groups-. Also phenyl alkoxysilanes having 2-3 alkoxy groups in the monomeric silane or 0-2 alkoxy groups in the oligomeric alcohol-soluble condensation product can thus be used according to the invention. This is true, of course, also for other combinations, such as for example phenylalkylsilanes and condensation." products prepared therefrom containing reactive (ester) groups which after hydrolysis are converted into OH-groups or already consist of hydrolysates or partial hydrolysates. ^' According to the invention alkyl alkoxysilanes, phenyl alkoxysilanes or alkoxy silanes having organo- -functional groups and tetraalkoxysilanes and/or their condensation products and/or their hydrolysates are added to the mortar at some stage during the process for its manufacture. One criterion for the use of silicon- -organic compounds according to the invention is that they are soluble in alcohol, i.e. contain a limited number of silicon atoms, preferably less than 10 - i.e. their molecules are preferably oligomeric. A measure for the suitability of the active preparations of being emulsified in water or a water-containing material is their solubility or compatibility with at least lower (monovalent) alcohols having up to 6 C-atoms, primarily their solubility in alcohols between methanol and propanol, inclusive, (or water) . This compatibility with alcohol (or water or alcohol-water mixture) does not delimit the choice of conceivable solvents for the silane or polysiloxane products (alkoxy polysiloxanes) used in the invention. If said products meet the criterion that they are

-fυR soluble in lower alcohols they can- according to the invention suitably be used for direct emulsifying in water or direct to the wet mortar or admixed with the dry mortar and its constituents, optionally while adding tensides/surfactants/emulsifiers at some stage of the process for preparing the wet mortar. Such products may also and optionally in the presence of catalysts be admixed and emulsified after they have (optionally together with tensides/surfactants/emulsifiers according to the invention) been dissolved in solvents of various types. As such solvents there may be used not only monovalent alcohols but also two- and three-valent lower alcohols and aromatic solvents. Typical examples of the latter type of solvents of hydrocarbon type are inter alia toluol, xylol, etc.

The mixture of silanes or siloxanes, tensides and catalysts according to the invention with aliphatic or aromatic solvents can be used to impart to the respective preparations easier handling during manufacture, for example in disposing and use, such as viscosity changes, density changes, storage stability, avoidance of risk for unvoluntary contact with water etc.

Reactions taking place between hydraulic binders and so-called ballast or filler materials containing or consisting of reactive silica and between such ballast and filler materials are known. Such alkali- -silica reactions occur inter alia in the manu¬ facture of lightweight concrete products and lime sandstone between slaked or/and unslaked lime,

Portland cement, (granulated) shaft furnace slag, filter dust, fly ash and similar products and as indicated ballast and filler materials containing or consisting of silica. It has now been found that it is possible to provide binding corresponding to the binding arising inter alia in autoclaving by mixing into the wet mortar at some stage during the process for its manufacture finely divided reactive silica. It has surprisingly been found that admixture of reactive silica according ^• to the invention can be provided by emulsifying tetra alkoxy silanes, so-called silica esters, in monomer or oligomer form and optionally their hydrolysates into the mortar at some stage of the process for its manufacture. Admixing can take place in the same manner and if required with the same tenside/sur- factant/emulsifiers and optionally catalysts as above when using alkylalkoxy silanes, their condensation and their hydrolyzation products when modifying products prepared from wet mortars containing hydraulic binders. Adding silica esters (tetraalkoxy silanes) and/or their condensation products and/or their hydro- lysate products can take place separately or in admixture with alkyl, phenyl, alkylphenylalkoxy silanes or alkoxy siloxanes and in other respects according to the process of the invention.

The silicon-organic compounds which according to the invention may be used for hydrophobation of hardened masses prepared from wet mortar are alkyl and/or phenyl and/or alkylphenyl alkoxy silanes and their condensation and hydrolysis products. The con¬ densation products used according to the invention are preferably so-called oligomeric silanes using an old term or using a new term called oligomeric (alkoxy) polysiloxanes.

The length of the alkyl groups and the size of the phenyl groups and the length of the alkoxy groups, i.e. the number of C-atoms contained therein, vary in view of the requirement that silica-organic compounds shall be soluble in lower alcohol and is relatively limited. The alkyl groups may contain up to 35 carbon atoms, but a number of carbon atoms less than 20, preferably less than or equal to 10 should be used. From economic reasons of production the ^'upper limit for the number of carbon atoms in the alkoxy group is five, a preferred number being two or/and three. When using silica esters (tetraalkoxy silanes) in monomeric or oligomeric form there are used for the latter preparations molecules containing less than 10 silicon atoms. In such silica esters the alkoxy residue shall be an ethoxy residue or longer, i.e. contain equally to or more than two carbon atoms, from environ¬ mental reasons. When using methoxy residues precaution- ary steps should be taken (closed process) for environ¬ mental reasons.

Modification of hardened mortars made according to the invention takes place by adding to the mortar at some stage during the process for its manufacture silicon-organic preparations of a particular type con¬ sisting of or prepared from alkylalkoxy silanes, phenyl alkoxy silanes or tetraalkoxy silanes together with or in the presence of tenside/emulsifier/surfactants (and optionally catalysts). In order to disperse such active silicon-organic preparations, optionally in solvents, according to the invention into water or water-con¬ taining mortars or water-containing mixtures of mate¬ rials or the dry constituents of the mortar tensides may be used. As tensides/emulsifiers/surfactants according to the invention there may be used anionic and non-ionic tensides, preferably non-ionic tensides. Among the non-ionic tensides there are used preferably tensides which are compatible with or soluble in lower alcohols and in active silane or siloxane preparations according to the invention. Examples of anionic tensides which are conceivable are the following: Sulphonated and sulphurated esters, amines and polyethers, sulphonated and sulphurated fats, oils and fatty acids. Reaction products between fatty acids and binary, tertiary, quaternary organic amines and, of course, soap etc. Examples of preferred non-ionic substances suitable as emulsifiers are - alcohol-alkylene oxide adducts and esters.

Particularly preferred surfactants are the following: Sorbitane fatty esters, polyoxyethylene sorbitane fatty esters, polyoxyethylene fatty esters and polyoxyethylene fatty alcohol ethers and polyoxy¬ ethylene adducts.

Conventional names for such preparations are inter alia polyoxyethylene stearate, sorbitane monooleate, sorbitane mqnopalm.i a e, sorbitane monostearate, sorbitane tristearate, sorbitane monooleate, sorbitane trioleate, polyoxyethoxysorbitane monooleate, mono- palmitate, monostearate, -tristearate, -monooleate, -trioleate etc.

Among the tensides useful for the purpose of this invention such tensides can be used which loose their surface-active properties - they shall be capable of decomposition - at some stage during the process of manufacture, but at the latest before taking into use the building product prepared from wet mortar so that the effect of surfactant does not reduce the desired effect of the active hydrophobating/modifying prepa¬ ration. The surface-active tensides may loose their surface-active properties from one or some of the following reasons:

Alkaline or acid substances, oxidation or reduct¬ ion agents, heat or radiation.

A preferred method for decomposing tensides is to allow them according to the invention to decompose by the alkalinity of the building material or the heat used under the process of manufacture. If there is used according to the invention non-alkali resistant, preferably non-ionic substances as emulsifiers one can obtain the advantage that the emulsion is degraded already during the state of manufacture of mortar containing hydraulic binders, said stage in accordance with known technique being determined by the quantity of surfactant additive so that the local concentration of the active preparations according to the invention is not carried to a higher degree than desirable.

In view of the fact that in principle hydrophilic as well as hydrophobic groups are bund to the silicon atom in the silicon-organic compounds according to the invention, tensides may be used which are soluble in oil- and tensides may be used which are soluble or emulsifiable in water. It has been found that a mixture of such types of tensides sometimes gives the best result. It has been found that mixtures between 10/90 % and 90/10 % can give better results than the addition of individual types of tensides.

One purpose of the invention is - if desired - to provide prepolymerized or polymerized particles, which as to function are similar to powder, in one single process in connection with the manufacture of the wet mortar. This is according to the invention done by using a type of catalyst, i.e. substances promoting condensation and polymerization of alkoxysilanes to polysiloxanes (in the presence of moist or water). Such substances are known from the art of preparing silicon products of alkoxysilanes.

Examples of catalysts useful according to the invention are as follows:

Catalysts for use in the process according to the invention can consist of (silan(ol)polymerization)cata- . lysts and (silan(ol)condentation)catalysts which in most cases also are hydrolysis catalysts, in accordance with known technique, above all catalysts which hydro- lyze, polymerize and condensate silanes/silanols, siloxanes and silicons. Some alkoxy silanes are hydrolyzing themselves. Other alkoxy silanes are hydrolyzed at acid or alkaline reaction.conditions. Examples of such catalysts are given in the following: A first group consists of catalysts, for example according to Swedish patent No. 381 453*, which are either organofuctional silanes with basic organo- -groups and/or alcoholates of silicon and/or of metals from the first and/or the second main group and/or fourth and/or fifth side group in the periodic system. These catalysts are hydrolyzable.

Another group of catalysts to provide and accelerate silane and silanol condensation and possibly polymerization with substrates is described in U.S. patent No. 3 328 481, namely organic amines with a preferred constant of dissociation of at least 10 -10, preferably primary, secondary and tertiary amines.

Another group of useful catalysts for the process of the invention is also given from U.S. patent specification 3 328 48l and are known from another context, i.e. silicon manufacture as condensation products between aliphatic aldehydes and aliphatic primary amines.

Another conceivable and important group of cata- lysts for the process according to the invention are metal salts of carboxylic acids and polycarboxylic acids and hydroxycarboxylic acids. The metals in this instance are inter alia lead, tin, nickel cobalt, iron, cadmium, chromium, zinc, copper, manganese, aluminium, magnesium, barium, strontium, calcium, cesium, sodium, potassium, lithium, titanium and zirconium and vanadium. Some specific examples of such types of catalysts are given for example in Swiss patent specification CH 594 576 using the same catalysts but in another connection than in the process of the in¬ vention, namely in the preparation of a particular binder.

Another type of silanopolymerization catalysts are metal oxides. Yet another agent to provide silane and silanol- polymerization and optional coupling of silan(ol)s to the OH-groups of the substrate in the mortar are chelate complexes. A particular type of chelate complexes used in the preparation of silicons is ^■ obtained by reaction of metal alcoholates and chelates^ a process which is described in principle in Belgian patent B 564 179. The chelate complex is obtained according to the principles illustrated in said patent specification are prepared from metal acid esters, the chelates being beta diketones^ betaketone esters, beta hydroxy or betaamino ketones and similar substances. Further examples of chelates are given in U.S. patent specification 3 153 000.

Yet another group are organic peroxides. Such cata- lysts are quite flexibly useful. They can be admixed with or dissolved in either water and/or alcohols and/or conventional organic solvents and/or mixtures thereof. Some catalysts may even be evaporized and transported in gas form. Certain catalysts, for example from the classes naphthenates and octoates, are silicon- and silanesolubel.

The catalysts suitable for the process of the invention can be selected from the above groups (singly or in combinations, simultaneously or in sequence), the choice being taken while considering requirements and desiderata, such as way of transportation, technique for application, properties of material and way of functioning etc. Thus, for example catalysts prepared from metal alcoholates and chelates may either be prepared before the application or they can be formed in situ in that the individual components are introduced 'separately, possibly together with other components in the preparations in the process of the invention. In the process according to the invention combi¬ nations of alkoxysilanes and different combinations of catalysts not specified above but in accordance with known technique, used for polymerization and conden¬ sation of polymers, may be used. In order that the reactions required to provide for treatment of the substrate according to the process of the invention shall be initiated, take place or be terminated presence of water is required to provide for hydrolysis of the hydrolyzable components present in the treating agent or agents. Such water can be found in the substrate or may be supplied to the substrate by methods known per se. The mortar may, however, also be present in the components for the preparation of the respective hydrolysates or in the transport medium, and water is, of course, also present as mixing-, process¬ or reaction water in the manufacture of mortar masses in gas or liquid form or when cooling is required in the form of ice.

As catalysts there may be used catalysts used within silicon technology to prepare polymers from alkoxy silanes. Preferred catalysts are those soluble in alkoxy silanes or/and lower alcohols. Catalysts can function also as tensides/emulsifiers/surfactants or vice versa. The supply of such catalysts can take place together with the alkoxysilane or solutions thereof,

OMP catalysts being admixed with or dissolved or dispersed in the silane, optionally together with alcohol and surfactant according to the invention.

The catalyst may also be added in some form to parts of the wet or dry mortar during the process of preparing the wet mortar. The catalyst can be added to all mixtures or-mixture variations of the effective preparations according to the invention, namely alkoxy silane, tenside/surfactant/emulsifier, alcohol or alcohol and water mixture or each separately.

The catalysts can be soluble in alcohols and can then be added to, admixed with or dissolved in silanes. Also solutions of catalysts in conventional solvents of aromatic or aliphatic type can be used to admix catalysts with the silane or with the mortar. Catalysts can also be dispersed in silanes. Also in admixing cata¬ lysts with silanes and tensides the techniques for admixing with the dry or wet mortar as described early can be used. In particular, the process of adding emulsions or dispersions and suspensions of alkoxy silanes, their condensation products and their hydrolysis products to the dry or wet mortar can be supplemented according to the invention by adding catalysts to said mixtures, preferably to the alkoxy silane before admixing into the continuous phase. In such a manner a so-called precondensation or pre- polymerization of the alkoxy silane will be provided already before admixing the dispersion into the mortar, the time for forming polymers in the wet mortar decreasing.

According to the invention special silanes and (oligomeric) polysiloxanes may be added to the mortar at some stage during its process of manufacture. Silane emulsions (containing also tensides and optionally catalysts) may be added to the ballast or parts thereof. They can be added to the mixing water. They can be added to the binder (for example if the binder is activated before admixture with the mortar). They can be added to the dry mortar as a whole or to parts thereof or a particular pulverulent carrier sub¬ stance. They can also be added to the wet mortar. In addition to being dissolved in a lower alcohol silicon- organic compounds according to the invention and/or tensides/surfactants/emulsifiers or catalysts, may be dissolved also in solvents in accordance with con¬ ventional technique of the type hydrocarbon oils, which in some cases also in a conventional manner can function as additives, such as for example foam stabilizers.

Particles of active substances according to the invention may also be provided with the quantities of water required to prepare the wet mortar either as a whole or parts thereof. Also in this case some methods are preferred in accordance with the invention. Binde /ballast or parts thereof can be mixed with silicon-organic compounds and/or surfactants and/or catalysts or solvents. Such surface-active preparations according to the invention can be added also to the water/mineral grain mixtures used in the preparation of gypsum- products (full process water or parts thereof act as a continuous phase in a dispersion) .

Active preparations can be mixed with blowing agents, such preparations and conventional additives being used as carrier substances in mixing. Active preparations according to the invention may also be added to the wet mortar in some stage of its manu¬ facture. The quantities of active preparations used (silicon-organic compound and tenside) can be added in mixture or separately at different stages during the process of manufacture of a wet mortar from the prepa- ration of the ballast material (optionally including

Ol.lPI grinding and wetpainting) until the mortar has been given the form and the pore volume which is a requisite for desired properties and function of a hardened mortar.

_ 5 As earlier indicated silanes and polysiloxanes tensides and catalysts can be added according to the invention to the_ wet mortar directly either together or individually. According to the invention parts of the mortar can optionally be treated with alkoxy silanes

10 and other parts of surfactant before the respective parts are admixed (and other parts with the catalyst). A special way of providing emulsions of silanes, mainly alkoxy silanes or their hydrolysis and conden¬ sation products, according to the invention is the

15 following: Parts of the consituents of the dry mortar, being either fractions or parts of the ballast, of the binder or a particular pulverulent fine-grained carrier substance, are treated on their surfaces with alkoxy silanes, surfactant, such as emulsifier; (and

20 alcohol), catalysts or mixtures thereof.

Plaster mortars and gypsum products as such are not silanol-reactive. In order that the silane shall hydro- lyze and condensate sometimes acid or alkaline reaction conditions or/and presence of catalysts will be

25 required.

In case alkaline mixing conditions are to be obtained for hydrolysis and polymerization of silanes and silica esters and other esters, such can be provided by adding for example alcoholates of alkaline

30 earth or alkali metals in the form of powder or a solution to the dry powder. Such alcoholates hydrolyze after contact with the mixing water and provide hereby alkaline reaction conditions for polymerization and other reactions. Alkaline and acid reaction conditions

35 in mixtures containing water can, of course, be

OMPI provided in ary other ways. Alkaline mixing con¬ ditions are obtained for example by adding slaked or unslaked lime, cement, granulated shaft furnace slag to the dry mortar, the wet mortar or their constituents or by using certain catalysts according to the invention. The addition of active preparations (silanes, tensides, catalysts) of individual substances or mixtures thereof takes place in the form of concen¬ trates, solutions or emulsions in a liquid form, solid form or suspensions or in the form of gases or aerosols. As preferred solvents there may be used lower alcohols or other polar solvents. As a transport medium for aerosols there may be used water vapour or air or mixtures thereof. As an emulsifier (continuous phase) for the addition of emulsions or suspensions there may be used water or alcohols or mixtures thereof.

The addition of alkoxy silanes to mortars can be freely selected but for economic reasons it should be less than 5 % of the dry weight of the binder, preferably within the range 0.1 - 3 % • The surfactant/ emulsifier additive constitutes θ.l o/oo - 10 % of the silane weight, preferably within the range 1 o/oo - 10 % . Silane or the silane/surfactant mixture can contain alcohol compatible with water, preferably lower alcohol, such as methanol, ethanol (preferably) and propanol, or non-water soluble aliphatic and aromatic solvents between 0 and 200 % of the silane weight (siloxane weight), preferably within the range 10-50 % . Moreover, it has been found that reduced addition of surfactant also can give certain positive effects: The size of the drops in the preparation during mixing increases, which is an effect that technically can be utilized if distribution of the modifying effect is desirable, for example with regard to the strength of the material, particularly when the preparations are

-n

O admixed into the dry or wet mortar in the form of aerosols, optionally prepared by mechanical atomization by spraying.

Catalyst additives used in accordance with the invention are delimited to 10 % of the weight of the silane for economical reasons with a lowermost limit of technical reasons of 0.1 o/oo. The preferred range is between 1 o/oo and 5 % of the weight of the silane.

The process according to the invention can be used for manufacture of building elements and building com¬ ponents of various types, such as ordinary and finishing mortars, concrete, light ballast concrete, clinker con¬ crete, light concrete, sandstone products and the like.

* %E fr

Claims

PATENT CLAIMS:

1. A process for the preparation and modification of hardened mortars, a wet mortar being prepared in accordance with conventional technique, said wet mortar consisting of or containing one or several hydraulic binders, filler and ballast material, the major part ^•being mineral material, water and* additives, charact¬ erized by adding to the mortar or its solid components at some stage or at different stages during the process of its manufacture alkoxy silanes and/or their conden¬ sation products and/or their hydrolysis^' products, optionally together with an aliphatic or aromatic solvent, optionally with tensides/surfactants/emulsi- fiers, optionally with (silanol) polymerization/con¬ densation catalysts.

2. A process for the preparation of a modified hardened mortar, characterized thereby that the alkoxy silane, tenside and catalyst are added in liquid, gaseous or solid form, in the form of concentrate, solutions, emulsions, suspensions or in the form of aerosols thereof.

3- A process according to any of the preceding claims, characterized thereby that the alkoxy silane is an alkylalkoxy silane and/or a phenylalkoxy silane and/or a tetraalkoxy silane.

4*. A process according to any of the preceding claims, characterized thereby that the added alkoxy silanes and/or their condensation products and/or their hydrolysates constitute between 0.1 and 5-0, preferably between 0.1 and 3-0 % £>y weight of the dryweight of the binder.

5. A process according to any of the preceding claims, characterized thereby that the added sur- factant/tenside/emulsifier is between 0.1 o/oo and ^ ^Q 10 , preferably between 1 o/oo and 5 % by weight of the weight of silane.

6. A process according to any of the preceding claims, characterized thereby that- the surfactant/ten- side/emulsifier is decomposable, that it looses its surface-active properties in the presence of a reduction agent, oxidation agent, acid or basic substances.

7. A process according to any of the preceding claims, characterized thereby that the added poly¬ merization/condensation catalyst constitutes between 0.1 o/oo and 10 , preferably between 1 o/oo and 1 of the weight of silane.

8. A process according to any of the preceding claims, characterized thereby that the added aliphatic or aromatic solvents, preferably lower alcohol, con¬ stitute between 0 and 200 of the weight of silane (weight of siloxane), preferably within the range

10 to 50 % by weight.

9- A process according to any of the preceding claims, characterized thereby that the binder, filler or ballast material wholly or partly contains or consists of reactive silica.

10. Products prepared by the process according to any of the preceding claims.