WO2020038582A1

WO2020038582A1 - Mixture that can be mixed with water and contains shaped hydrophobic silicic acid bodies and humectant

Info

Publication number: WO2020038582A1
Application number: PCT/EP2018/072784
Authority: WO
Inventors: Niklas WIENKENHÖVER; Christoph MÜLLER-REES; Richard Weidner
Original assignee: Wacker Chemie Ag
Priority date: 2018-08-23
Filing date: 2018-08-23
Publication date: 2020-02-27

Abstract

The invention relates to a mixture (M) which can be mixed with water and contains a) binder (B), b) shaped bodies (F) made of hydrophobic pyrogenic silicic acid, and c) humectant (G). Also disclosed is a process for producing a coating compound, wherein the mixture (M) that can be mixed with water is mixed with water.

Description

Water-miscible mixture containing hydrophobized silica, shaped bodies and wetting agents

The invention relates to a water-miscible mixture containing binders, moldings made of hydrophobized

pyrogenic silica and wetting agent, and a method for producing a coating composition in which the

Water mixable mixture is mixed with water.

There is a need for malleable insulation materials for buildings, such as plasters, that are non-flammable, inexpensive and easy to use

are applied.

As inorganic (high-performance) insulation materials are used in the

Literature called perlite, expanded glass, silica granules and aerogels:

The thermal conductivity of the perlite used according to the state of the art for thermal insulation plasters is moderate. Thermal plasters provided with pearlites have WLF values

(Thermal conductivity values) in the range of 60 mW / (m K). The mechanical stability of perlites in insulating plasters is not particularly pronounced, so measures to stabilize these fillers are described. In EP2543652B1 closed-row perlites are preferably used over open-row perlites.

Aerogels are particularly delicate due to their small pore sizes and very thin pore interfaces. To stabilize the aerogels, EP0489319B1 describes them

additionally integrated in a stabilizing matrix made of styrene foam. Alternatively, aerogels are mixed with other fillers, the latter forming a type of support structure for the mechanically weaker aerogels (WO 2015/090615 Al). Responsible for the thermal insulation effect of thermal insulation plaster is the insulation material, so that its volumetric share

should be as high as possible: According to the teaching of DE102012020841A1, the proportion of binder in the overall system should be as low as possible so that the insulation effect of the plaster is not too strong

is deteriorating.

The fillers used for insulating plasters must be hydrophobic, as described in EP2799409A1 for perlite.

Insulation plastering applications, like other solutions in the construction sector, are high-volume applications and therefore require one for them

End customers have a good cost-performance ratio. Aerogels are expensive due to their complex manufacturing process.

EP181868B1 describes the use of polymer particles (based on PS, PE, PU) provided with small anionic or anionic nonionic surfactants on the surface, which stabilize air bubbles formed in mortar. This

Polymer particles have no function as thermal

insulating filler.

US4157998B describes the use of surfactants as auxiliaries for the stabilization of air pores in building materials, e.g. in mortar.

The invention relates to a water-miscible

Containing mixture (M)

a) binder (B)

b) molded body (F) made of hydrophobicized pyrogenic silica and c) wetting agent (G).

The mixture (M) can be used to produce insulation materials that are non-flammable, inexpensive and easy to use

are applied. The molded bodies (F) contained in the mixture (M)

Hydrophobicized fumed silica is one

High-performance thermal filler. They have a

significantly lower WLF than perlite.

The molded articles (F) have a better cost performance than aerogels, since the molded articles (F) are made of pyrogenic

Silicic acid are built up and the underlying pyrogenic silicic acid after its compression is good for

Thermal insulation performance has already formed the necessary pore structure.

An insulation material with molded bodies (F) is after

Application hydrophobic, so that the WLF of the insulation material is largely preserved even when water is introduced due to the weather. In addition, the freshly applied mixture (M) can dry off within an acceptable time window.

The mixture (M) preferably contains an inorganic or an organic binder (B) or as a binder (B)

Mixtures of these. Examples of inorganic binders (B) are cement, such as Portland cement, white cement,

Alumina cement and pozzolan cement. Further examples of inorganic binders (B) are lime-based binders, such as hydrated lime Ca (OH) 2, which are characterized by dry adsorption

Lime (CaO) is obtained and hydraulic lime, namely calcium hydroxide Ca (OH) 2, which is mixed with small amounts of a hydraulic binder, in particular cement. Other examples of inorganic binders are

gypsum-based binders, such as calcium sulfate hemihydrate or hemihydrate (CaS04 * 0.5 H2O), in the alpha and in the beta

Form as well as in the form of, for example, building plaster, stucco, model plaster or insulating plaster (English stucco or plaster of paris), and anhydrites (CaS04, anhydrite I, II and III), as they are obtained from known calcination processes, starting from existing gypsum stone or artificially produced gypsum. In the calcination process, the phases calcium sulfate dihydrate, calcium sulfate hemihydrate and anhydrite I, II and III in their various forms can be different

Ratios and mixtures arise (multi-phase plaster). Other types of gypsum, such as screed gypsum, marble gypsum, anhydrite,

Recycling gypsum and artificially produced gypsum (at the

Flue gas desulfurization, the manufacture of phosphorus and

Hydrofluoric acid or organic carboxylic acids) are suitable.

Further examples of inorganic binders (B) are

Silicone resins, alkysiliconates and alkali silicate and preferably of the general formula (Si0 _{2) m (} M ₂ 0) _n , where M is selected from Li, Na, K and NH ₄ and mixtures thereof and the molar

Ratio m: n is at most 3.0, preferably at most 2.0, particularly preferably at most 1.7, in particular at most 1.2.

Examples of organic binders (B) are water-based thermosetting binders, such as epoxy resin or polyurethane, and dispersion binders based on thermoplastic

Acrylate, styrene acrylate or styrene butyl acrylate polymers.

The shaped bodies (F) preferably have a bulk density of 60-250 g / L, particularly preferably 65 to 200 g / L, particularly preferably 70 to 160 g / L, in each case determined according to DIN ISO 697.

The moldings (F) can be produced by any method from all hydrophilic known to the person skilled in the art

fumed silica. The moldings (F) are preferably produced in a process in which

i) a mixture containing the hydrophilic silica is coated with hydrophobicizing agent,

ii) the mixture from step i is deaerated and

iii) the mixture from step ii is compacted to a target bulk density.

Granulation preferably takes place during the compaction in step iii.

Fumed silicas or precipitated silicas or mixtures thereof are preferably used in the production of the shaped bodies (F). Furthermore, silicas with a BET surface area according to DIN 66131 (determined with nitrogen) of between 50 and 800 m ² / g are particularly preferred

between 100 and 500 m ² / g and particularly preferred

Silicas with a surface area between 150 and 400 m ² / g are used. In the context of this invention, hydrophilic means that the Si-OH groups are accessible on the surface and the

Silicas are wettable by water.

As further components in the manufacture of the

Shaped body (F) additives are added that can absorb, scatter or reflect heat rays in the infrared range. They are commonly referred to as IR opacifiers.

These clouders preferably have a maximum in the IR spectral range of preferably between 1.5 and 10 mih. The

The particle size of the particles is preferably between 0.5-15 ml. Examples of such substances are preferred

Titanium oxides, zirconium oxides, ilmenites, iron titanates, iron oxides, zirconium silicates, silicon carbide, manganese oxides and carbon black. Furthermore, to reduce the electrostatic charge, if necessary, all additives known to the person skilled in the art for reducing the electrostatic charge, such as conductive alkylammonium salts, can be added.

Additional fillers can be added for technical and / or economic reasons. Synthetically produced modifications of are preferably used here

Silicon dioxide, such as. B. aerogels, precipitated silicas, arcing silicas, SiCy-containing dusts, which are caused by oxidation of volatile silicon monoxide in the

electrochemical production of silicon or ferrosilicon arise. Likewise, silicas, which are leached by

Silicates such as calcium silicate, magnesium silicate and

Mixed silicates such as olivine can be produced with acids. Furthermore, naturally occurring compounds containing SiO ₂ are used, such as diatomaceous earth and diatomaceous earth.

To ensure good processability (e.g. flowability and

Granulability) of the mixture containing silica

being able to ensure is preferred

Embodiment dispenses with the addition of fibers.

The mixture preferably contains hydrophilic

Silica, which is coated with hydrophobicizing agent in step i, at most 85% by weight of hydrophilic silica.

All substances known to the person skilled in the art for the hydrophobization of silicas can be used as hydrophobicizing agents, in particular organosilicon compounds (e.g. organosilanes, organosiloxanes, alkylsiliconates or silicone resins) and

Hydrocarbons (e.g. paraffins, waxes, carboxylic acids, especially fatty acids). The preferred hydrophobizing agents are at 25 ° C.

liquid, reactive organosilanes, organosiloxanes or

Silicone resins are used, which have hydrophobic properties and to react with the Si-OH groups

Silica surface are capable.

The water repellents can be pure or in any

Mixtures are used.

The reactivity of those used is preferred

The hydrophobizing agent has been selected such that the reactions or interactions for binding the hydrophobizing agent to the silanol groups of the hydrophilic silica are only completed after step iii has been carried out.

Organosilanes of the general formula are preferably used as water repellents

R ¹ _n R ² _m SiX _{4- (n + m) (} I) used,

where n and m can be 0, 1, 2 or 3 and the sum n + m is less than or equal to 3 and

R ^{1 is} a saturated or mono- or polyunsaturated, monovalent, optionally with -CN, -NCO, -NR ³ , -COOH, -COOR ³ , -halogen, -acrylic, -epoxy, -SH, -OH or -CONR ³ 2 substituted Si-C bonded Ci-C2o ^_ hydrocarbon radical, preferably a Ci-Cis hydrocarbon radical, or an aryl radical, or C1-C15 hydrocarbonoxy radical, preferably a Ci-Cs hydrocarbonoxy radical, particularly preferably a C1-C4 hydrocarbonoxy Radical in which one or more methylene units which are not adjacent to one another are each separated by groups -0-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NR ³ - can be replaced and in which one or more, not each other

neighboring methine units can be replaced by groups, -N =, -N = N-, or -P =, where

R ^{2 is} hydrogen or a saturated or mono- or polyunsaturated, monovalent, optionally with -CN, -NCO, -NR ³ 2, -COOH, -COOR ³ , -halogen, -acrylic, -epoxy, -SH, -OH or - CONR ³ 2 substituted Si-C bonded Ci-C2o ^_ hydrocarbon radical, preferably a Ci-Cis hydrocarbon radical, or an aryl radical, or Ci-Ci5-hydrocarbonoxy radical, preferably a Ci-Cs-hydrocarbonoxy radical, particularly preferably a C1- C4- hydrocarbonoxy radical, in each of which one or more methylene units which are not adjacent to one another are replaced by groups -0-, -CO-, -COO-, -OCO-, or -OCOO-, -S- or -NR ³ - can be and in which one or more, not each other

R ^{3 has} the same meaning as R ² , and R ² and R ³ can be the same or different,

X is a C-0 bonded Ci-Ci5 hydrocarbon residue, preferably a Ci-Cs hydrocarbon residue, particularly preferably a

Ci-C3 hydrocarbon residue, or an acetyl residue, or a halogen residue, preferably chlorine, or hydrogen, or a

OH residue means

or

R ¹¹ _i R ²² _j Si-Y-SiR ¹¹ _i R ²² _j (II)

in which

R ^{11 has} the meaning of R ¹ and R ^{22 have} the meaning of R ² ,

i and j can be 0, 1, 2 or 3 and the sum of i + j is 3 and

Y can be the group NH or -0-. There are preferably chain or cyclic, branched or unbranched organosiloxanes consisting of building blocks of the general formulas

(R ⁴ _a Z _b SiOi _{/ 2} ) (III-a)

(R ⁴ ₂ Si0 _2/2 ) (IH-b)

(R ⁴ Si0 _3/2 ) (III-c)

(R ⁴ R ⁵ Si0 _2/2 ) (Ill-d)

(Si0 _4/2 ) (Ill-e) used,

where the building blocks can be contained in any mixtures, where

R ⁴ are R ¹ and R ⁵ are R ² , and Z are X and are each the same or

may be different, and a and b may be 0, 1, 2, or 3, with the proviso that the sum a + b is 3.

Cyclic organosiloxanes are preferably used.

Chain-like organofunctional ones are also preferred

Organopolysiloxanes used, consisting of preferably 2 units of the general formula III-a and preferably 1 to 100,000 units of the general formula III-b and preferably 1 to 500 units of the general formula III-d, preferably 1 to 50,000 units of the general formula III-b and

preferably 1 to 250 units of the general formula III-d, particularly preferably 1 to 10000 units of the general formula III-b and preferably 1 to 200 units of the general formula III-d, and very particularly preferably 1 to 5000 units of the general formula III-b and 1 to 100 units of the general formula III-d, where R ^{4 is} preferably methyl and R ^{5 is} preferably -CH2-CH2-CH2-NH2 or -CH2-CH2-CH2-NH-CH2-CH2-NH2.

Chain-shaped organopolysiloxanes are preferably used, consisting preferably of 2 components of the general formula III-a and preferably 1 to 100,000 components of the general formula III-b, preferably 1 to 50,000 components of the general formula III-b, particularly preferably 1 to 10,000 components of the general Formula III-b, and particularly preferably 1 to 5000 units of the general formula III-b, R ⁴ preferably methyl. Chain-shaped organosiloxanes are particularly preferred

used, the R ^{4 is} preferably methyl and the Z is preferably -OH.

The kinematic viscosity of the organosiloxanes measured at 25 ° C. is preferably 1 mm ² / s to 100000 mm ² / s, preferably 2 mm ² / s to 10000 mm ² / s and particularly preferably 5 mm ² / s to 1000 mm ² / s ,

OH-terminated are particularly preferred

Polydimethylsiloxanes used, which preferably a

Kinematic viscosity measured at 25 ° C from 5 mm ² / s to 100 mm ² / s.

Networked or partially networked are also preferred

Organopolysiloxanes, so-called silicone resins, are used, which are preferably the building blocks of

general formula III-a and building blocks of the general formula III-e contain, particularly preferably with R ⁴ equal to methyl, a equal to 3 and b equal to 0, or those which preferably

Building blocks of the general formula III-c and building blocks of contain general formula III-b, particularly preferably with R ⁴ being methyl.

The amount of hydrophobizing agent added in step i depends on the specific surface area (BET surface area) of the

Silicas, their share in the mixture, the type of silanes or siloxanes, and that required for the end use

Hydrophobicity. The amount added is preferably at least 1.5% by weight, particularly preferably at least 10% by weight,

particularly preferably at least 15% by weight, based in each case on the entire mixture.

In a preferred embodiment, the components are mixed. The hydrophobicizing agent is preferably added in liquid form during the preparation of the mixture, it being necessary for the individual components to be thoroughly mixed. The hydrophobizing agent is preferably adsorbed by spraying the silica with the liquid hydrophobizing agent in the

Fluid bed or in the fluidized bed.

The temperature is preferably selected in the range from 15 to 35 ° C., so that the hydrophobizing agent used during the mixing process in step i and before the compression in

Step iii does not yet fully react with the silanol groups on the silica surface. This temperature setting ensures that the coated silica largely behaves like a hydrophilic silica with regard to processability in terms of compression, in particular granulation. This is crucial for the production of granules with an optimal combination of hydrophobicity and mechanical stability. The rate of addition and the subsequent stirring time of the hydrophobizing agent are generally chosen so that thorough mixing is ensured.

After step i and before compaction in step iii, the mixture is preferably stored only briefly. The storage period of the mixture is generally chosen so that the hydrophobizing agent used has not yet reacted completely with the silanol groups on the silica surface during the mixing process or before compaction.

The storage period until compaction is preferably at most 15 days, particularly preferably at most one week, in particular at most 3 days, very particularly preferably

at most 24 hours, especially preferred, the material is compressed and granulated immediately.

Since silicas, in particular pyrogenic silicas or

Mixtures containing silica usually have very low bulk densities, the challenge in the production of granules is to remove the air. If the mixture from step ii is deaerated, the molded bodies obtained do not expand and disintegrate again after the pressing process.

Adequate ventilation can be achieved, for example, by very slow compression. Such slow compression steps cannot be used economically for large-scale, in particular continuous, production. It is therefore advantageous to actively deaerate the silica. This can be achieved, for example, by using reduced pressure. A can already occur during the venting

Volume decrease of the mixture take place. The venting and subsequent compression and granulation can either in different devices or in a device that fulfills both functions.

After the mixture has been produced in step i, it is preferably brought to the desired density by compacting or pressing in step iii. In general, higher compression results in harder, more stable particles. This compression can be carried out by all methods known to the person skilled in the art. It should be noted that a higher

Compression leads to a higher thermal conductivity of the granules. The pressure used during step iii is preferably chosen so that a compromise between the

Thermal insulation effect and the mechanical stability of the granules is achieved.

In order to be able to avoid additional process steps, a preferably takes place simultaneously during the compression

Shaping. Depending on the pressing process, you can

various shapes, sizes and size distributions

can be set. Free-flowing moldings are often used for applications in building insulation.

Shaped bodies are generally understood to mean all shapes which can be produced by means of devices for compacting powders known to the person skilled in the art.

Shaped bodies (F) are preferably understood to mean shapes which can be produced by compaction by means of rollers (smooth or perforated) (for example sleeves, sleeves, platelets, rods, briquettes, tablets, pellets, spheres, lenses, fragments, fragments). The average size of the shaped bodies (F) is preferably at least in one dimension, preferably in two dimensions, particularly preferably in all three dimensions at most 100 mm, particularly preferably at most 50 mm,

particularly preferably at most 10 mm.

Equipment known to the person skilled in the art can be used for the compacting.

The compacting is preferably carried out as a dry compacting in such a way that the mixture is pressed in a compacting unit between two rotating rollers, wherein

particularly preferably at least one, particularly preferably both rollers has depressions, such as flutes, troughs or pillows. The rollers can be straight or concave. The compacted material formed in this way is then screen-granulated and fractionated to the desired particle size fraction. For the combination of a compacting with a subsequent screen granulation and fractionation e.g. an apparatus from Hosokawa Alpine Compaction can be used.

Furthermore, it can be advantageous if at least one roller is designed in such a way that a

Suppression can be generated (filter roller) through which the mixture to be compacted is sucked onto the roller and thereby vented. Preferably takes place after suction and

Vent the compression to the desired density using a suitable counter roller (press roller) instead. All devices known to the person skilled in the art, e.g. the Vacupress from Grenzebach BSH are used. The vent and

Compression takes place in succession in one device.

The supply of the silica to the compacting unit can be done by means of all means known to the person skilled in the art, such as

for example, conveyor screws or twin screws. In a particularly preferred embodiment, funnels and screw conveyors are used for metering and conveying, which at least partially have surfaces (for example the screw itself, the wall or special internals) on which a negative pressure can be generated and thus the ventilation

takes place.

After compacting, the sleeves and

Granules that exceed the size required for the application are separated and / or crushed. This can be carried out by all methods known to the person skilled in the art, for example by breaking, classifying or grinding. The fragments obtained are then separated into different grain fractions. For example, a sieve mill from Hosokawa Alpine can be used for this

Compaction can be used.

Particles can also be separated, which the

fall below the required size. All methods known to the person skilled in the art for sieving or classifying bulk goods can be used. The different grain size fractions are preferably separated by sieving. Particles that are too small can e.g. due to increased dust formation, may be disadvantageous for the end use.

After granulation of the shaped body (F), this can be done

Hydrophobing agents react completely with the silanol groups of the silica. In a preferred embodiment, this takes place without tempering, e.g. by storage at

Room temperature. The storage time of the shaped bodies (F) at room temperature is preferably at least 3 days, preferably at least one week, particularly preferably at least two weeks. This final water repellency can also be achieved with a Temperature increase can be accelerated. In a preferred embodiment, the shaped bodies (F) are tempered at a temperature of preferably from 60 to 300 ° C. and

particularly preferably at 70 to 130 ° C. The final binding of the hydrophobizing agent to the SiOH groups after the granulation can also be accelerated by adding catalytically active substances. For this purpose, all compounds known to the person skilled in the art can be functional for activation

Organosilicon compounds such as Bröndsted or Lewis acids can be used. Examples of Bröndsted acids are hydrochloric acid, sulfuric acid or nitric acid, hydrochloric acid is preferably used as Bröndsted acid. Lewis acids which can be used are, for example, tin or titanium compounds such as tin alkoxides or titanium alkoxides.

The shaped bodies (F) can, however, also be produced by pressing hydrophilic fumed silica and subsequent treatment with water repellents, for example by

Hydrophilic fumed silica is first compacted and, after compacting has been carried out, it is subsequently hydrophobized in a second step, e.g. described in DE102012211121A1.

The proportion by weight of moldings (F) is preferably outside a size range from 0.1 mm to 15 mm, particularly preferably a range from 0.5 mm to 10 mm, very particularly preferably a range from 0.8 mm and 6.0 mm, particularly preferably in a range of 1.0 mm and 4.0 mm

10%.

In order to be able to obtain moldings (F) with good insulating properties and stabilities, these moldings are preferably compacted to the desired bulk density. The thermal conductivity of the shaped bodies (F) in the form of a loose bed is preferably at most

35 mW / (m * K), preferably at most 30 mW / (m * K), particularly

preferably at most 28 mW / (m * K) and particularly preferably at most 26 mW / (m * K), the thermal conductivity at

Room temperature is measured with the aid of a THB transient hot bridge analyzer from Linseis, D-95100 Selb, and for this measurement the shaped bodies (F) are placed in a cylindrical

Measuring device are filled, the measuring sensor is inserted through a slot in the middle of the cylinder and the molded body (F) are then compressed.

The moldings (F) preferably have a C content of 1 to 10% by weight, particularly preferably 2 to 8% by weight, in particular 3 to 6% by weight.

The methanol wettability of the shaped bodies (F) is preferably measured by mechanically comminuting the shaped bodies (F) to particle sizes smaller than 0.5 mm, pouring 2 mL of the comminuted shaped bodies (F) into transparent centrifuge tubes, then the centrifuge tubes with a Methanol / water mixture containing 0, 10, 20, 30, 35,

40, 45, 50, 55, 60, 70 or 80 vol .-% methanol to 8 mL

be filled, the sealed centrifuge tubes are then shaken for 30 s and then centrifuged at 2500 min-1 for 5 min., the sediment volumes are then read, converted into percent and graphically plotted against the

Methanol content (in vol .-%) and the

The turning point is determined, which corresponds to the methanol wettability in the curve obtained. The water-miscible mixture (M) preferably contains 20 to 95% by volume, particularly preferably 40 to 90% by volume,

in particular 50 to 85 vol .-% of moldings (F).

In the water-mixable mixture (M) can be used as

Wetting agents (G) all previously known wetting agents (G), in particular the ionic and non-ionic surfactants, can be used both individually and as mixtures of different surfactants. The wetting agent (G) can also be a particulate substance, in particular a mineral substance

Substance, for example a powdered silica.

The silica is preferably a fumed silica, in particular partially hydrophobic. Preferably, the

partially hydrophobicized fumed silica has a carbon content of 0.01-10% by weight, in particular 1 to 5% by weight.

The particulate substance preferably has a methanol wettability of at most 90% by volume, in particular at most 80% by volume.

Examples of anionic wetting agents (G) are:

1. Alkyl sulfates, especially those with a chain length of 8 to 18 carbon atoms, alkyl and alkaryl ether sulfates with 8 to 18 carbon atoms in the hydrophobic radical and 1 to 40 ethylene oxide (EO) or propylene oxide (PO) units.

2. sulfonates, especially alkyl sulfonates with 8 to 18 carbon atoms, alkylarylsulfonates with 8 to 18 carbon atoms, taurides, esters and half-esters of sulfosuccinic acid with monohydric alcohols or alkylphenols with 4 to 15 carbon atoms; optionally these alcohols or alkylphenols can also be ethoxylated with 1 to 40 EO units.

3. Alkali and ammonium salts of carboxylic acids with 8 to 20 carbon atoms in the alkyl, aryl, alkaryl or aralkyl radical. 4. partial phosphoric acid esters and their alkali and ammonium salts, especially alkyl and alkaryl phosphates having 8 to 20 carbon atoms in the organic radical, alkyl ether or alkaryl ether phosphates

8 to 20 carbon atoms in the alkyl or alkaryl radical and 1 to 40 EO units.

Examples of nonionic wetting agents (G) are:

5. Polyvinyl alcohol, which still has 1 to 50%, preferably 2 to 20% vinyl acetate units, with a

Degree of polymerization from 500 to 50,000.

6. Alkyl polyglycol ethers, preferably those with 3 to 40

EO units and alkyl residues of 8 to 20 carbon atoms.

7. Alkylaryl polyglycol ethers, preferably those with 5 to 40 EO units and 8 to 20 C atoms in the alkyl and

Aryl residues.

8. ethylene oxide / propylene oxide (EO / PO) block copolymers,

preferably those with 8 to 40 EO or PO units.

9. Addition products of alkylamines with alkyl radicals of 8 to 22 carbon atoms with ethylene oxide or propylene oxide.

10. Fatty acids with 6 to 24 carbon atoms.

11. Alkyl polyglycosides of the general formula R * -0-Z0, in which R * is a linear or branched, saturated or unsaturated alkyl radical with an average of 8-24 carbon atoms and ZO one

Oligoglycoside residue with on average o = 1-10 hexose or

Pentose units or mixtures thereof.

12. Natural products and their derivatives, such as lecithin, lanolin, saponins, cellulose; Cellulose alkyl ether and

Carboxyalkyl celluloses, the alkyl groups of which each have up to 4 carbon atoms.

13. Linear organo (poly) siloxanes containing polar groups, in particular containing the elements 0, N, C, S, P, Si,

in particular those with alkoxy groups with up to 24 carbon atoms and / or up to 40 EO and / or PO groups.

Examples of cationic wetting agents (G) are:

14. Salts of primary, secondary and tertiary fatty amines with 8 to 24 carbon atoms with acetic acid, sulfuric acid, hydrochloric acid and phosphoric acids.

15. Quaternary alkyl and alkylbenzene ammonium salts,

in particular those whose alkyl groups have 6 to 24 carbon atoms, in particular the halides, sulfates, phosphates and acetates.

16. Alkylpyridinium, alkylimidazolinium and

Alkyloxazolinium salts, in particular those whose alkyl chain has up to 18 carbon atoms, especially the halides, sulfates, phosphates and acetates.

The following are particularly suitable as ampholytic wetting agents (G):

17. Long-chain substituted amino acids, such as N-alkyl-di (aminoethyl) glycine or N-alkyl-2-aminopropionic acid salts.

18. Betaines, such as N- (3-acylamidopropyl) -N, N-dimethylammonium salts with a C8-C18 acyl radical and alkylimidazolium betaines.

Preferred wetting agents (G) are nonionic surfactants, in particular those listed above under 6

Alkyl polyglycol ether. The wetting agent (G) can be selected from one of the above. Surfactants or from a mixture of two or more of the above Surfactants exist, it can be in pure form or as solutions of one or more surfactants in water or organic

Solvents are used.

The mixture (M) can contain further additives which are selected from fillers and additives, such as air entraining agents, binder auxiliaries, fluxes, retarders, Water repellents, pigments and agents for improving workability.

Examples of fillers are non-reinforcing fillers, i.e. fillers with a BET surface area of up to 50 m ² / g, such as quartz, diatomaceous earth, calcium silicate, zirconium silicate, zeolites, metal oxide powder, such as aluminum, titanium, iron, or zinc oxides or their mixed oxides, barium sulfate,

Calcium carbonate, gypsum, silicon nitride, silicon carbide,

Boron nitride, glass and plastic powder; reinforcing fillers, i.e. fillers with a BET surface area of at least

50 m ² / g, like fumed silica, precipitated

Silica, carbon black, such as furnace and acetylene black and silicon-aluminum mixed oxides with a large BET surface area. The above

Fillers can be hydrophobic, for example

by treatment with organosilanes or organosiloxanes or by etherification of hydroxyl groups to alkoxy groups. It can be a type of filler, a mixture of at least two fillers can also be used.

Examples of pigments are earth pigments such as chalk, ocher, umber, green earth, mineral pigments such as titanium dioxide, chrome yellow, red lead, zinc yellow, zinc green, cadmium red, cobalt blue, organic pigments such as sepia, Kasseler Braun, indigo, azo pigments, antrachinoid, Indigoide, dioxazine, quinacridone,

Phthalocyanine, isoindolinone and alkali blue pigments, whereby many of the inorganic pigments also act as fillers and vice versa.

The content of fillers in the mixture (M) is

preferably at most 0 to 30% by weight, particularly preferably 0 to 20% by weight, in particular 0 to 10% by weight. The invention also relates to a method in which the water-miscible mixture (M) is combined with water to form a

Coating compound is mixed.

Preferably 100 parts of mixture (M) with 50 to 180 parts by weight, particularly preferably 80 to 160 parts by weight,

in particular 100 to 140 parts by weight of water mixed.

The coating composition is preferably processed to insulating materials, in particular thermal insulation plasters.

Examples

In the following examples, unless stated otherwise, all quantities and percentages are based on weight, all pressures are 0.10 MPa (abs.) And all temperatures are 20 ° C.

1 . Where to Buy

1 . 1 Fumed silica

a) HDK ^® T30: hydrophilic, pyrogenic silica from Wacker Chemie AG, with a BET surface area of 300 m ² / g.

b) HDK ^® H30: hydrophobic, pyrogenic silica from Wacker Chemie AG, with a BET surface area of 300 m ² / g and a

Residual silanol content of approx. 50%.

c) Pyrogenic silica, with a BET surface area of

200 m ² / g and a residual silanol content of approx. 80%

(Production described in DE102010062839A1 [0112]).

d) HDK ^® H15: hydrophobic, pyrogenic silica from Wacker Chemie AG, with a BET surface area of approx. 150 m ² / g and a

Residual silanol content of approx. 50%. 1.2 OH-terminated polydimethylsiloxane

OH-terminated polydimethylsiloxane from Wacker Chemie AG with a kinematic viscosity in the range of 12 - 15 mm ² / s.

1.3 Other aids

Sodium dodecyl sulfate (CAS number: 151-21-3) and

Polyvinyl alcohol (molar mass: 9000 - 10000 g / mol; CAS number: 9002-89-5) was obtained from common suppliers.

2. Production of the shaped bodies from hydrophobicized pyrogenic silica

2.1 Coating of a hydrophilic fumed silica with

Hydrophobicizers

In the first step, the hydrophilic fumed silica HDK ^® T30 is coated with 15% by weight of OH-terminated polydimethylsiloxane as a hydrophobizing agent. For this purpose, part (approx. 10%) of the hydrophilic fumed silica to be covered is combined in one

Containers with the total amount of OH-terminated

Polydimethylsiloxane stirred until an optically homogeneous

Mixture of the powdery hydrophilic fumed silica in the liquid OH-terminated polydimethylsiloxane is formed. The stirring takes place e.g. by a magnetic stirrer or by a dissolver. After that, the so obtained

Premix with the remaining hydrophilic pyrogenic

Silica is mixed vigorously with addition in portions in a dissolver until a homogeneous mixture is again obtained. The powder mixture obtained in this way is then compacted.

2.2 Forming the shaped body: compacting the with a

Hydrophobing agents covered pyrogenic silica and subsequent comminution The powder mixture prepared in accordance with 2.1 is filled into a mold (110 x 110 x 180 mm) on the day it is filled at room temperature. On the filled with this powder mixture

A stamp is then applied to the die

Bring powder mixture to its target bulk density in the range of 80 - 250 g / L. Here, the stamp on the

Powder mixture filled press mold. The

Target bulk density is based on the quantity filled in

Powder mixture controlled. The feed of the stamp must be selected so that the air can slowly escape over the edge of the stamp (ventilation). For a thorough

Venting the feed of the punch is interrupted at about 80 - 90% for about 10 minutes (venting through the gap

between stamp and mold). The target bulk density is then compacted and waiting for another 10 minutes before removal from the mold. The stamp is then relaxed, which in this way becomes a plate (the plate thickness is approx.

20 mm) compacted mixture removed from the mold and then mechanically crushed into smaller moldings. Any formed bodies larger than 4 mm are separated off via a sieve and comminuted in such a way that they pass through the 4 mm sieve. The fine fraction of the shaped bodies created in this way is then removed using a hand sieve (mesh size 1 mm).

3. Evaluation of the shaped bodies made of hydrophobized silica

3.1 Bulk density of the shaped bodies

The bulk density of the shaped bodies is determined based on DIN ISO 697. For this purpose, the material to be examined is poured into a vessel with a known volume (1 L). Surplus material is wiped off with a bar. By weighing determines the weight of the bed and calculates the bulk density.

3.2 Determination of the methanol wettability to describe the hydrophobicity of the shaped bodies

Methanol wettability is a measure of the hydrophilicity / hydrophobicity of silica materials. For this purpose, a sample (approx. 15 g) of the molded body is mechanically crushed until it passes through a sieve with a mesh size of 0.5 mm. In transparent

Centrifuge tubes are filled with 2 mL (± 0.05 mL) of the powder to be examined and then with a previously prepared methanol / water mixture (0, 10, 20, 30,

35, 40, 45, 50, 55, 60, 70, 80 vol .-% methanol) made up to 8 mL. The sealed tubes are then shaken for 30 s and then centrifuged at 2,500 revolutions per minute for five minutes. The sediment volumes are then read, converted into percent and plotted against the methanol content (in% by volume). The turning point of the curve obtained corresponds to the methanol wettability.

For the moldings (F) used in the examples below, the methanol wettability is more than 55% by volume.

4. Production of a dry mixture containing moldings made of hydrophobized silica

4.1 Production of a cementitious binder matrix

The components for a cementitious binder matrix are mixed in a ratio according to Table 1 using a stirrer until an optically homogeneous mixture is formed. Table 1: plaster formulation

WITHOUT molded body (F)

4.2 Production of a dry mixture containing plaster mixture and molded body

80% by volume of the shaped body are added to the mixture (prepared in accordance with 4.1) and by conventional methods (e.g.

Shake this mixture in an air-filled, closed plastic bag) until an optically homogeneous dry mixture is formed.

5. Homogeneous water incorporation of a dry mixture

containing a) plaster mixture and b) moldings: 5.1 Comparative example

a) 300 mL water are placed in a Toni mixer (mortar mixer, Testing, Berlin, content: 5 liters), then 1 liter of the homogenized dry mixture from 4.2 is added and stirring is carried out in this mixer

(Stirring speed 140 revolutions per minute) for two

Minutes stirred. After this stirring time, none

obtained homogeneous mixture. Even with considerably longer stirring times, a homogeneous mixture is not obtained because the

Most of the moldings float on the cementitious binder matrix.

Summary: Shaped bodies with a methanol wettability of> 55% by volume cannot be incorporated into the cementitious binder matrix without further additives.

5.2 Example 1: Homogeneous water incorporation of a

Dry mix containing a) plaster mix, b) moldings and c) surfactants

a) 10 g of sodium dodecyl sulfate are dissolved in 300 ml of water. This solution is placed in a Toni mixer (mortar mixer, Testing, Berlin, content: 5 liters), then 1 liter of the homogenized dry mixture from 4.2 is added and with constant stirring in this mixer (stirring speed 140 revolutions per minute) for two minutes touched. After this period of stirring, a homogeneous mixture is obtained. b) 10 g of polyvinyl alcohol (molar mass: 9,000 - 10,000 g / mol) are dissolved in 300 ml of water. This solution is placed in a Toni mixer (mortar mixer, Testing, Berlin, content: 5 liters), then 1 liter of the homogenized

Dry mixture from 4.2 added and with constant stirring in this mixer (stirring speed 140 revolutions per minute) stirred for two minutes. After this period of stirring, a homogeneous mixture is obtained.

Summary: By adding ionic and non-ionic surfactants, moldings with a methanol wettability of> 55% by volume can be incorporated into the cementitious binder matrix.

5.3 Example 2: Homogeneous incorporation of a dry mixture containing a) plaster mixture, b) moldings and c) hydrophobicized pyrogenic silicas in water

(Stirring speed 140 revolutions per minute) for 20

Seconds stirred. With stirring, the

Add pyrogenic silica HDK ^® H30 and water until an optically homogeneous mixture is obtained. This homogeneous mixture contains a total of 50 g HDK ^® H30 and a total volume of water of 1000 mL. b) 300 ml of water are placed in a Toni mixer (mortar mixer, Testing, Berlin, content: 5 liters), then 1 liter of the homogenized dry mixture from 4.2 is added and stirring is carried out in this mixer

(Stirring speed 140 revolutions per minute) for 20

Seconds stirred. With stirring, the

pyrogenic silica according to 1.1b) and water added until an optically homogeneous mixture is obtained. This homogeneous mixture contains a total of 55 g of the pyrogenic

Silica according to 1.1b) and a total volume of water of 1100 mL. c) 300 mL of water are placed in a Toni mixer (mortar mixer, Testing, Berlin, content: 5 liters), then 1 liter of the homogenized dry mixture from 4.2 is added and stirring is carried out in this mixer

(Stirring speed 140 revolutions per minute) for 20

Seconds stirred. Then in portions

pyrogenic silica HDK ^® H15 and water are added until an optically homogeneous mixture is obtained. This homogeneous mixture contains a total of 70 g HDK ^® H15 and a total volume of water of 1300 mL.

Summary: By adding the partially hydrophobic fumed silicas, moldings with a methanol wettability of> 55% by volume can be added to the cementitious binder matrix

be incorporated.

Claims

claims

1. Containing mixture miscible with water (M)

a) binder (B),

b) molded body (F) made of hydrophobicized pyrogenic silica and

c) wetting agent (G).

2. Mixture (M) according to claim 1, in which the binder (B) is selected from lime-based binder,

gypsum-based binder, silicone resin, alkyl silicates, alkali silicate, organic binder and mixtures thereof.

3. Mixture (M) according to one or more of the preceding claims, in which the shaped bodies (F) have a bulk density of 60-250 g / L, determined according to DIN ISO 697.

4. Mixture (M) according to one or more of the preceding claims, in which the shaped bodies (F) have a C content of 1 to 10% by weight.

5. Mixture (M) according to one or more of the preceding claims, which contains 20 to 95 vol .-% of moldings (F).

6. Mixture (M) according to one or more of the preceding claims, in which the wetting agent (G) is selected from ionic and non-ionic surfactants and particulate substances.

7. Mixture (M) according to claim 6, in which as a particulate

Substance is a partially hydrophobicized fumed silica.

8. Mixture (M) according to claim 7, wherein the

partially hydrophobicized fumed silica has a methanol wettability of more than 55% by volume,

the methanol wettability of the pyrogenic silica is measured by the fact that the shaped body (F)

Particle sizes smaller than 0.5 mm are mechanically comminuted so that 2 mL of the comminuted shaped bodies (F) are filled into transparent centrifuge tubes, then the centrifuge tubes with a methanol / water mixture containing 0, 10, 20, 30, 35, 40, 45, 50,

55, 60, 70 or 80 vol .-% methanol are filled to 8 mL, the sealed centrifuge tubes are then shaken for 30 s and then at 2500 min-1 for 5 min.

are centrifuged, the sediment volumes are then read, converted into percent and plotted against the methanol content (in% by volume) and the inflection point is determined, which corresponds to the methanol wettability in the curve obtained.

9. A method for producing a coating composition, in which the water-miscible mixture (M) according to one or more of the preceding claims is mixed with water.