WO2020011354A1 - Mixture that can be made up with water, comprising shaped silica bodies - Google Patents

Abstract

The invention provides a mixture (M) that can be made up with water, comprising shaped bodies (F) composed of hydrophobized fumed silica having a thermal conductivity, measured in the bed, of not more than 35 mW/(m K), wherein the thermal conductivity is measured at room temperature with the aid of a THB Transient Hot Bridge Analyzer from Linseis, D-95100 Selb, and wherein the shaped bodies (F), for this measurement, are introduced into a cylindrical measurement apparatus, the measurement sensor is inserted through a slot in the middle of the cylinder and the shaped bodies (F) are then compressed, and a methanol wettability of the shaped bodies (F) of not more than 55% by volume, wherein the methanol wettability of the shaped bodies (F) is measured by introducing 2 ml in each case of the comminuted shaped bodies (F) into transparent centrifuge tubes, then making the centrifuge tubes up to 8 ml with a methanol/water mixture containing 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80% by volume of methanol, then shaking the closed centrifuge tubes for 30 s and subsequently centrifuging for 5 min. at 2500 min-1, then reading off the sediment volumes, converting to percent and plotting in the form of a graph against the methanol content (in % by volume) and determining the turning point corresponding to the methanol wettability in the curve obtained; and provides a process for producing a coating composition in which the mixture (M) that can be made up with water is mixed with water.

Description

 Water-mixable mixture containing silica

 moldings

The invention relates to a water-miscible mixture (M) containing shaped bodies (F) made of hydrophobicized pyrogenic silica and a process for producing a coating composition.

There is a need for moldable 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 conductivities of the perlite used according to the prior art for thermal insulation plasters are low. 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-cell perlites are preferred over open-line perlites.

 Aerogels are particularly delicate due to their small pore sizes and very thin pore surfaces. 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). The volumetric proportion of a filler in thermal plaster 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 deteriorated too much.

 The fillers used for insulating plasters must be hydrophobic, as described in EP2799409A1 for perlite. This statement is confirmed for aerogels in CH708679A2.

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. Due to their complex manufacturing process (incl.

Processing or necessary process aid recovery) too expensive, although it has been on the market for some years (Fixit 2017 price list: comparison between airgel insulation plaster with an insulation plaster based on perlite).

The invention relates to a water-miscible

Mixture (M) containing shaped body (F) made of hydrophobized pyrogenic silica with a thermal conductivity, measured in the bed, of at most 35 mW / (m K), the

Thermal conductivity is measured at room temperature with the aid of a THB transient hot bridge analyzer from Linseis, D-95100 Selb, and for this measurement the molded bodies (F) are filled into a cylindrical measuring device which

Measuring sensor is inserted through a slot in the middle of the cylinder and the moldings (F) are then compressed, and a methanol wettability of the moldings (F) of at most 55 vol .-%, whereby the methanol wettability of the moldings (F) is measured that 2 mL of the shredded shaped bodies (F) are filled into transparent centrifuge tubes, then the centrifuge tubes with a

Methanol / water mixture containing 0, 10, 20, 30, 40, 50, 60, 70 or 80 vol.% Methanol are made up to 8 mL, the sealed centrifuge tubes are then shaken for 30 s and then centrifuged at 2,500 min-1 for 5 min., the sediment volumes are then read, converted into percent and plotted against the methanol content (in% by volume) and the turning point is determined, which in the curve obtained shows the methanol Wettability corresponds.

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.

 Compared to aerogels, the shaped bodies (F) show better cost performance, since the shaped bodies (F) are made up of pyrogenic silica and the underlying pyrogenic silica has already formed the pore structure necessary for good thermal insulation performance after compression. In addition, the shaped bodies (F) can also be incorporated into a binder, such as e.g. a plaster matrix can be incorporated without destroying the porous structure, while the

production-related very hydrophobic aerogels only in

Particle sizes above about 1 mm can be incorporated into a typical hydrophilic plaster matrix without destroying it. An insulating material with moldings (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, and the freshly applied insulation material can also be used

dry within an acceptable time window.

Mixture (M) preferably contains a binder,

preferably an inorganic or an organic binder and mixtures thereof. Examples of inorganic binders are cement, such as Portland cement, white cement,

 Alumina cement and pozzolan cement. Other examples of inorganic binders are lime-based binders, such as hydrated lime Ca (OH) 2, which is 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 calcining processes, starting from existing gypsum stone or artificially produced plaster. 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,

Recycled plaster and artificially produced plaster (at the

Flue gas desulfurization, the manufacture of phosphorus and

Hydrofluoric acid or organic carboxylic acids) are suitable.

Other examples of inorganic binders are

Silicone resins and alkali silicate, preferably of the general formula (SZO2) _m (M2O) _nr where M is selected from Li, Na, K and NH4 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 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.

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

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

Silicas.

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

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

 ii) the mixture from step i is deaerated and

 iii) the mixture from step ii is compressed 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 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, which 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 m. 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, Si0 ₂ -containing dusts, which 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 To be able to ensure, the addition of fibers is dispensed with in a preferred embodiment.

The mixture preferably contains hydrophilic

Silicic acid, which is coated with hydrophobicizing agent in step i, at least 85% by weight, particularly preferably

at least 90% by weight, in particular at least 95% by weight of hydrophilic silica.

All substances known to those skilled in the art for the hydrophobization of silicas can be used as hydrophobicizing agents, in particular organosilicon compounds (e.g. organosilanes, organosiloxanes or silicone resins) and hydrocarbons (e.g. paraffins, waxes, carboxylic acids, especially fatty acids).

The preferred hydrophobicizing agents are liquid, reactive organosilanes, organosiloxanes or at 25 ° C.

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

Silica surface are capable.

The water repellents can be used neat or in any mixtures.

The reactivity of those used is preferred

Hydrophobing agent chosen so that the hydrophobizing effect is not fully developed before the compression step iii.

Organosilanes of the general formula are preferably used as water repellents

R ¹ nR ² mSiX4- (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 residue, preferably a Ci-Cis hydrocarbon residue, or an aryl residue, or C ₁ -C ₁₅ hydrocarbonoxy residue, preferably a Ci-Cs hydrocarbonoxy residue, particularly preferably a C ₁ - C ₄ - hydrocarbonoxy radical, in each of which one or more methylene units which are not adjacent to one another 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 residue, preferably a Ci-Cis hydrocarbon residue, or an aryl residue, or Ci-Ci5-hydrocarbonoxy residue, preferably a Ci-Cs-hydrocarbonoxy residue, particularly preferably a C ₁ -C ₄ - hydrocarbonoxy radical, in each of which one or more methylene units which are not adjacent to one another are formed 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 ^{3 has} the same meaning as R ² , and R ² and R ³ may be the same or different,

X is a C-0 bonded Ci-Ci5 hydrocarbon residue, preferably a Ci-Cs hydrocarbon residue, particularly preferably a C ₁ -C ₃ - Is a hydrocarbon radical, or an acetyl radical, or a halogen radical, preferably chlorine, or hydrogen, or an OH radical,

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 has} the meaning of R ¹ and R ^{5 have} the meaning of R ² , and Z have the meaning of X and can each be the same or different, and a and b can 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 units of the general formula III-a and preferably 1 to 100,000 units of the general formula III-b, preferably 1 to 50,000 units of the general formula III-b, particularly preferably 1 to 10,000 units 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

Polydimethylsiloxane used, the preferred one

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

 Crosslinked or partially crosslinked 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

Contain building blocks of the general formula III-c and building blocks of the 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 between 0.5 and 20% by weight, preferably between 1 and 15% by weight, particularly preferably between 5 and 12% by weight, in each case based on the mixture as a whole.

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 adsorption of the

Hydrophobing agent is preferably carried out by spraying the silica with the liquid hydrophobizing agent in the

Fluid bed or in the fluidized bed. The temperature is preferably selected so that the hydrophobicizing agent used does not yet react completely with the silanol groups on the silica surface during the mixing process in step i and before the compaction. This temperature setting ensures that the coated silica largely behaves like a hydrophilic silica in terms of processability in terms of compression, in particular granulation. For the production of

This is crucial for granules with an optimal combination of hydrophobicity and mechanical stability.

The addition rate and the stirring time of the

Hydrophobing agents are generally chosen so that intimate mixing is ensured.

After step i and before compaction in step ii, the mixture is preferably stored only briefly. The storage period of the mixture is generally chosen so that the hydrophobicizing agent used does not yet react 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 1 week, in particular at most 3 days, very particularly preferably

at most 24 hours, in particular, the material is compacted 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. Venting the mixture from step i causes the Do not inflate and disintegrate the molded bodies obtained 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 deaeration and subsequent compression and granulation can be carried out 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 ii. This is preferred in order to adjust the pore size with regard to an optimal insulation effect and to be able to obtain mechanically stable granules. In general, higher compaction results in harder,

more stable particles. This compression can be carried out by all methods known to the person skilled in the art.

 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 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 sieved 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 on the roller surface

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. Everyone can do this Devices known to the person skilled in the art, for example 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 (e.g. the screw itself, the wall or special fittings) 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, such as, for example, 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 short of the required size. All methods known to the person skilled in the art for sieving or classifying bulk materials can be used. The different grain size fractions are preferably separated by sieving. Particles that are too small can be disadvantageous for the end use, for example due to increased dust formation. After granulation of the shaped body (F), this can

Hydrophobing agents react 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 waterproofing can also be achieved by increasing the temperature

be accelerated. In a preferred embodiment, the shaped bodies (F) are tempered at a temperature of preferably from 60 to 300 ° C. and preferably from 70 to 130 ° C. The final binding of the hydrophobicizing 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 for activating functional organosilicon compounds, such as Brödsted or Lewis acids, can be used. Examples of Brøndsted acids are hydrochloric acid, sulfuric acid or nitric acid, preferred as Brøndsted acid

Hydrochloric acid used. Possible Lewis acids 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 hydrophobicizing agents, 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. in DE 10 2012 211 121 Al

described.

The proportion by weight of moldings (F) which is outside a size range of 0.1 mm to 15 mm is particularly preferred 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 a range from 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 7% by weight, particularly preferably 1 to 6% by weight, in particular 1 to 5% by weight.

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).

The mixture (M) may 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, ie fillers with a BET surface area of at least 50 m ² / g, such as pyrogenically prepared silica, precipitated

Silicic acid, carbon black, such as furnace black 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 mixture (M) which is miscible with water 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 otherwise stated, all quantities and percentages are based on weight, all pressures are 0.10 MPa (abs.) And all temperatures are 20 ° C.

1. Sources of supply a) Fumed silica

 HDK® T30: hydrophilic, pyrogenic silica from Wacker Chemie AG with a BET surface area of 300 m2 / g.

 HDK® N20: hydrophilic, pyrogenic silica from Wacker Chemie AG with a BET surface area of 200 m2 / g.

HDK® V15: hydrophilic, pyrogenic silica from Wacker Chemie AG with a BET surface area of approx. 150 m2 / g. b) OH-terminated polydimethylsiloxane (“OH-term. PDMS”): OH-terminated polydimethylsiloxane from Wacker Chemie AG with a kinematic viscosity in the range of 12-15 mm ² / s. c) Other aids: All other laboratory chemicals were obtained from common suppliers. d) Perlite (for comparative tests):

Knauf® Perlite: Superlite 0/6 - grain size: 0-6 mm; Bulk density: approx. 90 kg / m ³

AeroBall®: supplier Aero Dämm Technik, Müllheim; Grain size: 0.5-0.7 mm; Bulk density: approx. 78 kg / m ³

2. Production of the Shaped Bodies from a Hydrophobic Fumed Silica a) Covering a Hydrophilic Fumed Silica with

Hydrophobicizers

 In the first step, the hydrophilic fumed silica with different contents (% by weight) of OH-terminated

Polydimethylsiloxane as a hydrophobizing agent. For this purpose, part (approx. 10%) of the hydrophilic pyrogenic silica to be coated is stirred in a container with the total amount of OH-terminated polydimethylsiloxane until an optically homogeneous mixture of the powdery hydrophilic pyrogenic silica in the liquid OH-terminated

 Polydimethylsiloxane has arisen. The stirring takes place e.g. by a magnetic stirrer or by a dissolver.

 Then this premix obtained in this way is intensively mixed with the remaining hydrophilic fumed silica with addition in portions in a dissolver until a homogeneous mixture is again obtained. The powder mixtures obtained in this way are then compacted. b) Forming the shaped body: compacting the with a

Water repellents coated pyrogenic silica The powder mixture prepared according to a) 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 press mold, to which the

Hydrophobing agent to bring coated powders to their target density. The stamp is pressed onto the mold filled with powder mixture. The target density is controlled by the amount of the powder mixture. The feed of the stamp must be selected so that the air can slowly escape over the edge of the stamp (ventilation) without large amounts of the fine pyrogenic silica

escape. For a thorough ventilation, the feed of the punch is interrupted at about 80-90% for about 10 minutes (venting through the gap between the punch and the mold). The target density is then compacted and another 10 minutes waiting before demolding. The stamp is then relaxed, the mixture compacted in this way to form a plate (the plate thickness is approximately 20 mm) is removed from the press mold and then mechanically comminuted. Any formed bodies larger than 4 mm are separated using a sieve and comminuted so that they pass through the 4 mm sieve. The fine fraction of the shaped bodies created in this way is then sieved using a hand sieve (mesh size 1 mm).

3. Evaluation of the Shaped Bodies from Hydrophobicized Silica a) 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. The weight of the bed is determined by weighing and the bulk density is calculated therefrom. b) Thermal conductivity of the moldings

 The thermal conductivity is determined at

Room temperature on a bed of the molded articles produced using a THB Transient Hot Bridge Analyzer (THB-100) from Linseis, D-95100 Selb, using an HTP sensor. For molded articles made from pyrogenic silica, the measuring time is 45 seconds with a measuring current of 27 mA and a current for temperature measurement of 10 mA. The sensor is calibrated on a plate reference sample with the

thermal conductivity of 20 mW / (m * K). This plate sample is made from hydropilic fumed silica and measured for its thermal conductivity on the A206 from Hesto (method based on DIN EN 12667: 2001). For the perlite-based reference products, the measurement time is 10 seconds with a measurement current of 40 mA and a current for temperature measurement of 10 mA. The sensor is calibrated using a granular reference pattern with a thermal conductivity of 53 mW / (m * K). In accordance with DIN EN 12667: 2001, the device A206 (Hesto) is used for this

Thermal conductivity of a pearlite bed determined.

 For the measurement, 100 mL of the filler to be analyzed is poured into a cylindrical measuring device (material: PP, height 100 mm, cylinder diameter 80 mm), in the middle of which there is a slot (dimensions: 25 x 2 mm) through which the

Measuring sensor is inserted. Hydraulic plungers press the molded bed slightly from both ends during the entire measurement. c) hydrophobicity of the shaped bodies (qualitative)

 Approx. 20 g are used to assess the hydrophobicity

Shaped body in approx. 500 mL deionized water

Stored at room temperature. The moldings to be tested added to the water at the latest one week after their production.

 The hydrophobicity is assessed in two steps:

 a) Immediate test: assessment is carried out after the molded articles have been introduced into deionized water:

 + Hydrophobic: Molded bodies are hardly wettable by water and float completely on the water surface.

 0 Partially hydrophobic: moldings are wettable, but mostly float on the water surface.

 Not hydrophobic: moldings can be wetted immediately and sink down in the water within a few minutes. b) Test after 6 weeks of storage of the moldings in water:

 + Hydrophobic: Molded bodies are hardly wettable by water and at least 80% (number) float on the water surface.

 Partially hydrophobic: after six weeks of storage, moldings can be partially wetted by water and more than 20% float in the water. d) 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, 2 mL (+ - 0.05 mL) of the molded body to be examined are filled into a transparent centrifuge tube and then with a previously prepared methanol / water mixture (0, 10, 20,

30, 40, 50, 60, 70, 80 vol.% Methanol) to 8 mL. The sealed tubes are then shaken for 30 s and then centrifuged at 2,500 rpm for 5 minutes. The sediment volumes are then read off, in percent

converted and plotted against the methanol content (in% by volume). The turning point of the short obtained corresponds to Methanol wettability values entered in table 2, column 8).

4. Production of a plaster mixture containing moldings from hydrophobized silica a) Production of a plaster mixture:

 The components for a cementitious binder matrix are mixed in a ratio according to Table 1 using a stirrer until an optically homogeneous dry mixture is formed. By not adding one

Porosity agents in this plaster mixture can better compare the values for the thermal conductivity of the test bodies formed therefrom, since porosity agents usually have a strong influence on the thermal conductivity of applied thermal insulation plasters. b) Preparation of a dry mixture (M) containing

Plaster mixture and molded body (F):

 80% by volume of the shaped body (F) or of the reference filler perlite are added to the dry mixture (produced according to FIG. 4a)

added and by conventional methods (e.g. shaking this mixture in a closed air-filled

Plastic bag) until the formation of an optically homogeneous

Mixture mixed. c) Homogeneous incorporation of water into a dry mixture (M) containing plaster mixture and molded body (F):

 To produce a homogeneous mixture from the

Dry mixture containing plaster mixture and molded body (F) with water (pasting) is carried out as follows: - Preliminary test to determine the amount of water required for a test specimen: 200 mL of the components in Table 1

containing plaster mixture and 800 mL of the to be tested

Shaped body (F) (or the filler not according to the invention for comparison) are mixed until an optically homogeneous mixture has formed. This homogeneous dry mixture is then placed in a Toni mixer (mortar mixer, from Testing, Berlin, content 5 L) and to this

Mixture was first added to 100 g of water and stirred under 140 min-1 for 2 min. Then a further 20 g of water are added in portions and stirred again until a homogeneous, supple mass has formed. Such a mass is homogeneous and smooth when the water and the dry mixture can be mixed completely into a uniform phase and this phase is spreadable.

 The amount of water required for this filler is in the

Follow-up trial used.

Table 1: Plaster formulation

 WITHOUT molded body (F)

- Attempt to determine the duration until a homogeneous mass is formed (stirring time): 200 mL of the plaster mixture and 800 mL of the molded body to be examined (F) (or reference

Filler for comparison) are homogenized by shaking gently in a closed plastic bag. The in

The relative amount of water determined beforehand is placed in a Toni mixer, after which the homogenized plaster / molded body / reference filler mixture is added under

constant stirring in this mixer (stirring speed 140 min-1). The time between the addition of the solid mixture in the water until the formation of a homogeneous mixture is determined. d) Production of a test body from a dry mixture containing plaster mixture and molded body (F) or

Reference filler into which water has been homogeneously incorporated:

The paste produced under 4c) is transferred to a formwork (PE ring from our own production, diameter 200 mm) and first air-dried at 23 ° C for 3 days.

Then this test body in the formwork for another 3 days in a climatic cabinet at 50 ° C and 50% rel.

Humidity dried before the formwork is removed.

5. Evaluation of the test specimens from a dry mixture

containing plaster mixture and molded body (F) or

Reference filler into which water has been homogeneously incorporated a) Duration of incorporation until homogeneous incorporation of the

Dry mix in the water (duration homogenization for

Test specimen):

 The training period from the time between the addition of the dry mixture to the water provided until the formation of a homogeneous, pasted plaster is an empirically important measurement variable in practice for assessing which

(Mechanical, time) expenditure of thermal insulation plaster can be made before its (manual or mechanical) application. Typical values for commercially available thermal insulation plasters are in the range of a few 10 seconds. Test specimens with dry mixtures, for which the duration determined in this way until they are homogenized in the water is 300 s and more, are denoted by “> 300” and are not in practice reasonable

representable. b) Thermal conductivity of the test specimen:

 The thermal conductivity is based on DIN EN

12667: 2001 determined on a device named A206 from Hesto on circular test specimens with a diameter of approx. 200 mm at a temperature of 23 ° C.

6. Performed examples

The shaped bodies (F) are as in point 2 above.

described, the parameters relevant to the tests carried out being listed in Table 2 (columns 2, 3, 4).

Table 2

The bulk densities determined for these moldings are in Table 2 in column 5 and the qualitative evaluation of the

Hydrophobia listed in columns 8 and 9.

The test specimens are as described in point 4

manufactured. The incorporation times required for a homogenization of the dry mixture (containing plaster mixture and shaped body / reference filler) with the water are entered in column 10 of this table, the thermal conductivity of these test bodies in column 11.

7. Evaluation of the examples carried out (data in Table 2):

That for the application of with light fillers

Enriched thermal plaster is the decisive criterion for the homogenization of the dry mix with the

Water. It can be seen from Table 2 that Examples 1-11 meet the criterion of a homogenization period of less than 300 s, as do the comparative tests cf. 5 - cf. 7. In cf. For comparison, molded articles made of hydrophilic fumed silica are processed and evaluated: These

Shaped bodies can be used in insulating plasters with regard to their duration of homogenization, but as expected they show hydrophilic properties (negative hydrophobicity tests). Cf. 6 and cf. 7 perlite-based hydrophobic (reference) fillers available on the market and used for this purpose are processed: Homogenization and hydrophobicity properties are sufficiently good for their use in thermal insulation plasters, but their thermal conductivity is significantly higher than that of the moldings used according to the invention. The comparative tests cf. 1 - cf. 4 lead to in cannot be represented sufficiently well in practice

Homogenization _Z nits.

Through targeted variation of the weight proportion

Hydrophobing agent in relation to the used

Hydrophilic fumed silica can affect the mixing time

can be set. For a sufficient one in practice

The applicability of high-performance thermal plasters which contain molded articles (F) composed of hydrophobicized pyrogenic silica is therefore a minimal interaction between them

Shaped body with the aqueous plaster system required, which is due to a minimum number of reactive SiOH groups,

proven by the maximum methanol wettability is guaranteed. Shaped articles (F) with methanol wettability of more than 55%, on the other hand, are too hydrophobic to be able to be incorporated into water within a maximum incorporation period that is acceptable in practice for the target application of thermal insulation plaster.

From the experiments listed in Table 2 (1-11) for

Shaped body used according to the invention (made of

fumed silica and OH-terminated

 Hydrophobing agent PDMS) it can be seen that the values for the methanol wettability must be below 55% in order to be able to achieve a homogenization time of less than 300 s in the insulating plaster sample formulation shown in Table 1.

An increasing proportion of OH-terminated PDMS as

Hydrophobing agents in the moldings lead to a stronger hydrophobization, which is particularly positive in the hydrophobicity long-term behavior. However hydrophobic moldings result in a longer incorporation period until they are homogenized with water.

Fumed silicas (WACKER HDK® T30, BET ~ 300 m ² / g) coated with less than 15% by weight OH-terminated

 Water repellents PDMS can be homogenized sufficiently well with water, whereby - depending on the customer's requirements - their water repellency properties can be specifically adjusted.

The thermal conductivity of the moldings (F) listed in these examples is in the range between 19 and 22 mW / (m K) (measured in bulk with the aid of a THB

Transient Hot Bridge Analyzers from Linseis) and thus ~ 30 mW / (m K) below the values corresponding to pearlite fillings. The thermal conductivity values of the dried

Test specimens for molded articles based on pyrogenic silica are between 65 and 70 mW / (m K) and are therefore also approx. 30 mW / (m K) below the thermal conductivity values of test specimens with pearlite-based fillers.

Shaped bodies (F) used according to the invention have bulk densities in the range from 80 to 150 g / L in the tests carried out, and they are also particularly mechanically stable.

Claims

claims 1. Water-miscible mixture (M) containing shaped bodies (F) made of hydrophobicized pyrogenic silica with a thermal conductivity, measured in the bed, of  at most 35 mW / (m K), the thermal conductivity being measured at room temperature with the aid of a THB Transient Hot Bridge Analyzer from Linseis, D-95100 Selb, and for this measurement the shaped bodies (F) into one  cylindrical measuring device can be filled, the  Measuring sensor through a slot in the middle of the cylinder  is inserted and the molded body (F) then  be compressed, and  a methanol wettability of the moldings (F) from  at most 55% by volume, the methanol wettability of the shaped bodies (F) being measured by the fact that 2 ml of the comminuted particles are placed in transparent centrifuge tubes  Shaped body (F) are filled, then the  Fill the centrifuge tubes with a methanol / water mixture containing 0, 10, 20, 30, 40, 50, 60, 70 or 80 vol.% Methanol to 8 mL, then shake the sealed centrifuge tubes for 30 s and then at 2,500 min. 1 centrifuged for 5 min  Sediment volumes are then read off, 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. 2. Mixture (M) according to claim 1, which contains binder and in which the binder is selected from lime-based binder, gypsum-based binder, cement-based Binder, silicone resin, alkali silicate, organic  Binders 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, determined according to DIN ISO 697, of 60-250 g / L. 4. Mixture (M) according to one or more of the preceding claims, in which the proportion by weight of moldings (F) which are outside a size range from 0.1 mm to 15 mm is less than 10%. 5. Mixture (M) according to one or more of the preceding claims, in which the shaped bodies (F) have a C content of 1 to 7% by weight. 6. Mixture (M) according to one or more of the preceding claims, which contains 20 to 95 vol .-% of moldings (F). 7. 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. 8. The method of claim 7, wherein the with water  mixable mixture contains moldings (F) which are produced in a process in which  i) a mixture containing the hydrophilic silica is coated with hydrophobizing agent,  ii) the mixture from step i is deaerated and  iii) the mixture from step ii is compressed to a target bulk density.