WO2011018457A1

WO2011018457A1 - Moulded part

Info

Publication number: WO2011018457A1
Application number: PCT/EP2010/061628
Authority: WO
Inventors: Wolfgang Wirth; Peter Jahn; Daniel Decker
Original assignee: Frenzelit-Werke Gmbh
Priority date: 2009-08-11
Filing date: 2010-08-10
Publication date: 2011-02-17
Also published as: DE202009010871U1

Abstract

The present invention relates to a dimensionally stable, but not brittle moulded part, in particular a thermal moulded insulating part, of fibrous insulating material, which is characterised by the fact that only a minimum of additional substances have to be added to achieve dimensional stability. The actual structure of the fibrous material is not changed. Important product features such as the thermal conductivity or the vibrational resistance are not adversely influenced. The extremely small proportion of necessary organic additives can be lowered to virtually 0% by suitable process control, without losing dimensional stability. This meets the requirements of the market for high-temperature moulded parts, that no toxic substances may be given off under thermal exposure. Production of fumes is likewise inadmissible. Preferred areas of application are the automobile industry (for example as a moulded insulating part for heat shields, for example on the catalytic converter) but also any other application in which a dimensionally stable three-dimensional moulded part provides advantages over a two-dimensional blank, such as for example improved ease of positioning, easier separation into individual units, or general time-savings.

Description

MOLDING

Field of the invention

The present invention relates to a dimensionally stable, but not brittle, molded part, in particular a thermal insulation molding, of a fibrous insulating material, which is characterized in that only a minimum of additives must be added to achieve dimensional stability. The actual structure of the fiber material is not changed. Important product features such as thermal conductivity or vibration resistance are not adversely affected. The extremely low proportion of necessary organic additives can be reduced by suitable process control to almost 0%, without losing the dimensional stability. This takes into account the requirements of the market for high-temperature molded parts that no toxic components may be released when the temperature is applied. Smoke is also not allowed. Preferred fields of application are the automotive industry (for example heat shield insulation molding, for example on the catalyst) but also any other application in which a dimensionally stable three-dimensional molded part has advantages over a two-dimensional cutting, such as e.g. better positioning, easier separability, or generally time savings.

State of the art

Moldings of fibrous insulation materials for high temperatures have long been known. A well-known example are molded parts in the automobile end muffler, for example made of basalt wool or glass fiber, which are impregnated with phenolic resin or with other polymer-forming agents. These systems have the great disadvantage that to form a certain dimensional stability, a fairly high percentage of binder measured on the total weight of the molded part must be used. This results in the first time exposure to temperature to a strong smoke and depending on the conditions more or less strongly to the formation of hazardous substances. For example, this led to massive uncertainty among customers in the automotive industry. The market is therefore urgently looking for alternatives. Another major disadvantage of these systems are the hard residual particles that result from incomplete pyrolysis of the binder. (For this the usual application temperatures are too low). These crack residues can cause the fibers to be destroyed, especially during vibration, similar to the effect in a ball mill (so-called shot effect). The fibers are shortened more and more and thus the volumetric weight continues to increase until the fiber is finally discharged in the form of powder. The isolation is destroyed.

Another known method for the production of molded parts is the impregnation of fiber materials with sheet silicates (for example bentones or bentonites, that is to say clays) in the form of dispersions or slips. Although this system releases no toxic substances, with regard to the discharge behavior due to the abrasive pigments, d. H. the vibration resistance, but there is the same problem as described above. In addition, there is a risk in this process of recrystallization of the insulation fiber at higher temperatures, by reprecipitation between the oxides of the fiber and the inorganic binder used.

Moldings that are produced by the paper process in a vacuum process, must be fired to expel the binder. Due to the short fibers in this process creates a brittle material that is not resistant to vibration and thus can be easily discharged.

It is therefore an object of the present invention, a dimensionally stable, but not brittle, molding, in particular a thermal insulation molding, of a fibrous

Isolation material to produce, which already by adding a small Weight portion of a forming additive is dimensionally stable, without becoming brittle, has no odor, contains no toxic components or produced and yet has a high fire resistance, ie the building material class Al according to the standard DIN 4102 or Class A IfI according to the standard DIN EN 13501-1 (non-combustible building materials without fractions of combustible building materials).

Description of the invention

This object is achieved by a method for producing a dimensionally stable, but not brittle, molded part of a fibrous insulating material, in which a textile fabric containing glass fibers and / or silicate fibers is applied with at least one silazane in solution or as a solid (eg B. through

Impregnate). The textile fabric may be, for example, a nonwoven fabric

Knit fabric or a fabric. According to the invention, silazane is understood as meaning a monomeric, oligomeric or polymeric silazane. The silazane corresponds to one of the formulas I, II or III:

(II)

Here are

(a) R ² and R ^{3 are the} same or different and denote hydrogen or straight-chain, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, aryl, arylalkyl, alkylaryl, alkenylaryl or arylalkenyl, wherein each of the substituents R ² and R ³ in the case of m and / or o is greater than 1 in different units has a different or the same meaning,

R ² and R ^{3 are} identical or different and are straight-chain, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, aryl, arylalkyl, alkylaryl, alkenylaryl or arylalkenyl, where each of the substituents R ² and R ³ in the case of n and / or o greater than 1 in different units has a different meaning or the same meaning,

or

(b) if at least one radical R ³ and one radical R ³ are present, R ² and R ^{2 have} the meaning given above, and

(i) all, or

(ii) one part each

the radicals R ³ and R ³ together represent an unsubstituted or substituted, straight-chain or branched alkylene group, wherein in variant (ii) the remaining part of the radicals R ³ and R ^{3 has} the meaning given under (a). Furthermore are R ⁴ and R ^{4 are} alkyl, phenyl or hydrogen, it being possible for several radicals R ⁴ and / or R ⁴ to be identical or different in each case in one molecule of the compounds (I) to (III),

R ¹ and R ^{5 are} identical or different and may have the same meaning as R ² or R ³ , wherein R ^{5 may} also mean Si (R ') (R ² ) (R ³ ) or R ¹ and R ⁵ together represent a single bond,

R ⁶ Si (R ² ) (R ^{2 '} ) -XR ⁷ -Si (R ² ) _q (OR ^2' ) _3-q , wherein X is either O or NR ⁴ , R ^{7 is} a single bond or a substituted or unsubstituted, represents straight-chain, branched or cyclic alkylene group and q can be 0, 1, 2 or 3,

P is an alkylene group having 1 to 12 carbon atoms,

m and p are independently an integer between 1 and 25,000 and n and o are independently 0 or an integer between 1 and 25,000.

The units in square brackets are preferably distributed randomly in the respective molecule. Instead, they may also be distributed in blocks and, if appropriate, alternatively uniformly in the respective molecule. The term "units" refers in this case to the parts of the molecule which are each placed in a square bracket and provided with an index (m, n...) Indicating the amount of these units in the molecule.

Alternatively, the silazane may also correspond to formula IV

wherein R ⁸ and R ^{9 are the} same or different and are selected from the group consisting of hydrogen, organic groups and amino groups. R ¹⁰ is selected from the group consisting of hydrogen and organic radicals wherein the organic radicals are preferably selected from the group of straight-chain and branched C ₁ to C ₄ alkyl groups.

The indices m, n, o, p and q in the formulas I to IV are so dimensioned that the silazane has a number average molecular weight of 150 to 150,000 g / mol. The number average molecular weight of the silazane according to the invention is preferably 1,000 to 5,000 g / mol.

Particularly preferably, the silazane according to the invention corresponds to one of the formulas V or VI:

where the index m corresponds to the above definition. The number average molecular weight M _{n of} the silazanes according to the formulas V and VI is preferably from 1,000 to 5,000 g / mol. The textile fabric is then brought into shape, ie, after exposure to silazane, to obtain a green body. This can be done for example by pressing, in particular at a pressure in the range of 0.5 MPa to a maximum of 20 MPa. If appropriate, it is also possible to remove the solvent shortly before the shaping step at a temperature of, for example, up to 120 ^° C., without this impairing the dimensional stability of the green body. In the actual reaction, which leads to a stiffening of the molded part, it comes with elimination of a primary amine (NH ₂ R ⁴ or NH ₂ R ⁴ ) or for R ⁴ = H with elimination of ammonia (NH ₃ ) to chemical compounds between the fibers and the silazane. At the points of intersection of contacting fibers, bonding of the same occurs at this point. Here, an advantage (ie, an intermediate product) is obtained. As advantageous has the Use of dissolved silazanes proved because the formation of a surface of silazane is greatest in the crossing points here. The binding mechanism between two fibers is shown by way of example in FIG. 1 for R ⁴ = H. Finally, the advantage is further processed into a molded part as a final product.

In addition, it has proven particularly preferable to treat the dissolved silazane with a catalyst. This is selected from the group consisting of N-heterocyclic compounds, monoalkylamines, dialkylamines, trialkylamines, organic acids, inorganic acids, peroxides (especially dicumyl peroxide), azo compounds, metal carboxylates, acetylacetonate complexes, metal powders and organometallic compounds. This results in short reaction times, which in turn leads to short cycle times. The expulsion of the solvent can be drastically shortened by increased temperatures. When using silazane as a solid, one of these catalysts is preferably mixed with the solid silazane. The amount of catalyst to be used is known to the person skilled in the art and is at most 10% by weight, based on the silazane.

The remaining organic constituents can be subsequently removed by a heat treatment, without the stiffness of the molded part being lost. However, this is usually not necessary, since due to the small amounts of organic components under thermal stress of the molded part practically no smoke or odor development takes place. It should be emphasized in this process that the moldings thus obtained have a pronounced and permanent hydrophobicity, which is generally very advantageous for insulation.

Different Silanauflagen can be applied by means of programmable microdosing to reinforce areas of the molding targeted. Furthermore, the textile fabric may optionally contain incombustible pigments for coloring or opacifying, such as TiO ₂ as a white pigment. Antibacterial equipment can be made, for example, by silver particles which also do not increase flammability.

The fibers of the textile fabric are preferably selected from the group consisting of E glass fibers, R glass fibers, AR glass fibers and S2 glass fibers. Glass fibers with an SiO ₂ content of> 90% by weight produced by pickling from a precursor are particularly preferred.

In an alternative embodiment it is preferred that the fibers are selected from the group of KMF fibers (artificial mineral fibers) which are produced via a sol-gel process or via a green fiber by means of subsequent pyrolysis.

When mixtures of glass fibers and mineral fibers are used, the fabric preferably contains at least 10% by weight of glass fibers. Most preferably, it consists of 100% of glass fibers. An alternative to the use of fabrics is the manufacture of the molded article by making a blank by fiber spraying rovings and / or yarns, wherein the rovings and yarns of glass fibers and / or silicate fibers, and wherein the rovings and / or yarns in the fiber spraying with at least one silazane of one of the formulas I, II or III or formula IV is applied in solution or as a solid (for example by wetting). In fiber spraying, the rovings and / or yarns are cut and blown into a mold by means of air. This process replaces several textile production stages, such as weaving followed by confectioning, with a large amount of waste avoided. The diameter of the glass fibers and silicate fibers is preferably at least 5 μm, and the ratio L / D of length L to diameter D is> 3. Furthermore, it is preferred that the diameter of the fibers is a maximum of 30 μm. Such fibers are not respirable as defined by the World Health Organization (WHO), so that health risks such as pleural plaques, asbestosis, lung cancer or malaria. Mesothelioma can be excluded.

The at least one silazane is preferably used in dissolved form, the concentration of the silazane in the solution being 0.1 to 10% by weight. The concentration of silazane in the solution is particularly preferably 2 to 10% by weight. Furthermore, the amount of the solution or of the silazane solid used for the application is preferably selected so that the amount of silazane is less than 5% by weight, based on the weight of the textile fabric. In contrast to the prior art, which incorporates a large amount of ceramic or other substances in the fabric to achieve a shaping, according to the invention a very small amount of silazane is sufficient to make sufficient bonds between the glass fibers or silicate fibers, so that satisfactory dimensional stability is achieved. The silazane crosslinking product preferably constitutes 1 g / m ² to 100 g / m ² basis weight of the thermal insulation molding.

Particularly suitable solvents for dissolving the silazane are organic solvents which contain no water and no reactive groups (such as hydroxyl or acid groups). These are, for example, aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, esters such as ethyl acetate or butyl acetate, ketones such as acetone or methyl ethyl ketone, ethers such as tetrahydrofuran or dibutyl ether, and mono- and polyalkylene glycol dialkyl ethers (glymes) or mixtures of these solvents. The polysilazane solution may contain a filler from the group of ceramic powders. This filler is preferably selected from the group consisting of silicon carbide, silicon nitride, boron nitride, and metal oxides (for example, aluminum oxide).

In another preferred embodiment, the silazane is used as a solid, in particular in the form of a powder. After the application of the solid, it can be melted, for example, by means of infrared radiation, in order to detach it from the To prevent glass fibers during the shaping step. For this purpose, the solid silazane is preferably heated to 100 to 120 ⁰ C.

The shaping of the textile fabric can be done for example in a press.

The crosslinking of the silazane can be carried out at room temperature. Preferably, however, higher temperatures are chosen, such as up to 170 ⁰ C or higher, in order to accelerate the reaction. It is preferred that the temperature does not exceed 250 ^° C. The crosslinking is preferably carried out within 5 seconds to 10 minutes. When the solvent was shortly before the shaping step, for example by evaporation, removed a particularly rapid crosslinking of the silazane is possible because the crosslinking can be carried out at a temperature of up to 400 ⁰ C in this case.

The shaped part of a fibrous insulating material can be produced in a fully automated process.

With the method according to the invention a dimensionally stable, but not brittle molding is obtained. This may be, for example, a board or a plate or even a prefabricated part. However, it is particularly preferably a thermal insulation molding. This can, for example, for the thermal insulation of motors or engine auxiliary units, such. As catalysts are used to keep them at a sufficient operating temperature. Due to the dimensional stability can be saved in otherwise 3-layer heat shields (sheet metal, insulation, sheet metal) directed to the hot side sheet. Furthermore, the thermal insulation molding can be used in the installation and heating technology.

Brief description of the drawings

Figure 1 shows schematically the binding mechanism between two glass fibers in a molded part according to the invention. FIG. 2 shows a micrograph of the bond between two glass fibers in a molded part according to the invention.

Figure 3 shows a thermal insulation molding according to an embodiment of the invention.

Figure 4 shows a schematic representation of a board according to an embodiment of the invention. FIG. 5 shows a prefabricated part according to an embodiment of the invention.

The following examples serve to further illustrate the invention without limiting it: Examples

According to a first embodiment of the invention, a thermal insulation molding is produced by first a glass fiber fleece of fibers having a SiO ₂ content of at least 90 wt .-% with a basis weight of 960 g / m ² and a fiber length of the glass fibers of about 50 mm wt (isoTHERM ^® S Frenzelit) by means of a microdosing with a 5 wt .-% solution of a silazane of the formula VI (NL 120 from Clariant) in aromatic-free gasoline (petroleum ether) containing a total of 0.4 g of the silazane and further 3 .-% dicumyl peroxide (bis (1-methyl-1-phenylethyl) peroxide, DCP) based on the weight of the silazane used, is applied. The glass fiber fabric is introduced within 0.1 to 2 minutes in a mold which is heated to a temperature of 170 ⁰ C. The solvent contained in the web is evaporated after closing the mold, through suitable openings, within 30 sec. The actual crosslinking of the silazane then takes place within 2 min to 5 min. Crosslinking converts the web to an advantage in which the glass fibers are bonded together by the silazane such that the silica crosslinking product accounts for 30 g / m ² basis weight of benefit. This advantage then becomes a thermal one Further processing of insulation molding. The thermal insulation molding has a density of 260 kg / m ² and is temperature resistant up to 1100 ⁰ C. Its strength remains even after temperature exposure. A micrograph of the bond between two glass fibers in the thermal insulation molding is shown in FIG. The thermal insulation molding itself is shown in FIG. It has a surface dimension of 110 mm x 130 mm and a thickness of 5 mm. The thermal insulation molding has a weight of 30 g. 1.5% by weight of the molded part consists of the silicane crosslinking product. It is intended for use in the engine sector. According to a second embodiment of the invention, a board (plate) is prepared by first a glass fiber fleece of fibers having an SiO ₂ content of at least 90 wt .-% with a basis weight of 3,500 g / m ² , a thickness of 20 mm and a density of 175 kg / m ³ (isoTHERM ^® S Frenzelit) with 95 g / m ² or 4.750 g / m ^J of a silazane of the formula V (KiON ^® HTT 1800 and KiON Ceraset ^® polysilazanes 20 from Clariant) in powder form with a already introduced in the powder crosslinker, namely 3% DCP, is applied and is briefly melted by means of infrared irradiation at a temperature of 100 to 120 ⁰ C to prevent trickling out of the powder. After cooling, a storage-stable semi-finished product is thus obtained which can be further processed at a later time. This further processing takes place by pressing the semifinished product in a heated press at 300 ^° C. Depending on the wall thickness, the now stiff plate can be demolded within a few minutes. The board has a thickness of 10 mm and a density of 360 kg / m ³ . A schematic representation of the board is shown in FIG. This board can then be further assembled, for example with the help of a water jet, by drilling milling or sawing. A prefabricated part is shown in FIG.

According to a third embodiment of the invention a pre-fabricated part is produced by first forming a textile fabric of E glass fibers with a silazane of the formula V (KiON HTT ^® 1800 and KiON Ceraset polysilazanes ^® 20 from Clariant) is applied. The admission takes place here by a melting of the silazane and the swirling of the melt by means of compressed air through a nozzle. The substrate is applied with a uniform amount of silazane. In this case, the necessary crosslinker may already be present in the melt, in which case a peroxide must be used whose decomposition temperature is significantly above the melting temperature of the silazane used or else applied in advance to the substrate in an upstream step, for example by means of powder scattering. After cooling, a storage-stable semi-finished product is thus obtained which can be further processed at a later time. This further processing takes place, for example, by pressing the semifinished product in a heated press at 300 ^° C. Depending on the wall thickness, the now rigid plate or the now stiff molded part can be demolded within a few minutes. This advantage can then be further customized, for example by means of a water jet, by drilling milling or sawing. This method is especially for thinner wall thicknesses up. 6 mm, since the silazane does not penetrate into the textile fabric and the stiffening only takes place over the surface.

Claims

claims

A method of making a molded article from a fibrous insulating material, comprising the following steps:

Applying a textile fabric containing glass fibers and / or silicate fibers with at least one silazane of one of the formulas I, II or III in solution or as a solid,

wherein

(a) R ² and R ^{3 are the} same or different and are hydrogen or straight, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, aryl, arylalkyl, alkylaryl, alkenylaryl or arylalkenyl, wherein each of the substituents R ² and R ^{3 is} in the case from m and / or o greater than 1 in different units a different one or has the same meaning,

R ² and R ^{3 are the} same or different and are straight-chain, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, aryl, arylalkyl, alkylaryl, alkenylaryl or arylalkenyl, wherein each of the substituents R ² and

R ³ in the case of n and / or o greater than 1 in different units has a different meaning or the same meaning,

or

(i) all, or

(ii) one part each

the radicals R ³ and R ³ together represent an unsubstituted or substituted, straight-chain or branched alkylene group, where in variant

(ii) the remaining part of the radicals R ³ and R ^{3 has} the meaning given under (a),

and in which

R ⁴ and R ^{4 are} alkyl, phenyl or hydrogen, wherein several

Radicals R ⁴ and / or R ⁴ in each case one molecule of

Compounds (I) to (III) may be the same or different,

R ¹ and R ^{5 are the} same or different and have the same meaning as

R ² or R ³ may furthermore have, where R ⁵ can furthermore mean Si (R ¹ XR ² XR ^{3 '} ) or R ¹ and R ⁵ together represent a single bond,

R ⁶ Si (R ² ) (R ^{2 '} ) -XR ⁷ -Si (R ² ) _q (OR ^2' ) _3-q wherein X is either O or NR ⁴ , R ^{7 is} a single bond or a substituted or unsubstituted one represents straight-chain, branched or cyclic alkylene group and q is 0,

1, 2 or 3, P is an alkylene group having 1 to 12 carbon atoms, m and p are independently an integer between 1 and

25,000 mean, and

n and o are independently 0 or an integer between 1 and 25,000, where m, n, o and p are such that the silazane has a number average molecular weight of 150 to 150,000 g / mol, in particular from 1,000 to 5,000 g / mol and in which the units set in square brackets can be distributed uniformly, randomly or in blocks in the respective molecule, in a form of the textile fabric, in particular by pressing, optionally removing the solvent,

Conversion of the formed fabric by the crosslinking of the silazane and the reaction of the silazane with the fiber surface and concomitant bonding of the fibers of the fabric, preferably at the crossing points of the fibers, to a

Advantage, and

Processing the advantage to a molding. 2. The method according to claim 1, characterized in that the molded part is produced by applying different Silazanauflagen by means of programmable microdosing.

3. A process for producing a shaped article from a fibrous insulating material, comprising the following steps: Producing a blank by means of fiber spraying of rovings and / or yarns, wherein the rovings and yarns consist of glass fibers and / or silicate fibers, wherein the rovings and / or yarns in the fiber spraying with at least one silazane of one of the formulas I, II or III in solution or as Be acted upon solid

wherein

or

(i) all, or

(ii) one part each

and in which

R ⁴ and R ^{4 are} alkyl, phenyl or hydrogen, wherein several

Radicals R ⁴ and / or R ⁴ in each case one molecule of

Compounds (I) to (III) may be the same or different,

R ¹ and R ^{5 are the} same or different and have the same meaning as

25,000 mean, and

n and o are independently 0 or an integer between 1 and 25,000, where m, n, o and p are such that the silazane has a number average molecular weight of 150 to 150,000 g / mol, in particular from 1,000 to 5,000 g / mol , and wherein the units set in square brackets can be distributed uniformly, randomized or blockwise in the respective molecule,

Converting the blank by the cross-linking of the silazane and the reaction of the silazane with the fiber surface and concomitant bonding of the fibers of the blank, preferably at the crossing points of the fibers, to an advantage, and

Processing the advantage to a molding. 4. The method according to any one of the preceding claims 1 to 3, characterized in that the silazane is selected from the group consisting of the silazanes of the formulas V and VI and mixtures thereof:

(VI) wherein the silazane preferably has a number average molecular weight of from 1,000 to 5,000 g / mol. 5. The method according to any one of the preceding claims 1 to 4, characterized in that the fibers are selected from the group consisting of E glass fibers, R glass fibers, AR glass fibers and S2 glass fibers, wherein fibers produced by pickling from a precursor with a SiO ₂ content> 90 wt .-% are preferred. 6. The method according to any one of the preceding claims 1 to 4, characterized in that the fibers are selected from the group of KMF fibers, which are prepared via a sol-gel process or a green fiber by means of subsequent pyrolysis. 7. The method according to any one of the preceding claims 1 to 6, characterized in that the diameter of the fibers is preferably> 5μm and the ratio of the length L to the diameter D of the fibers L / D> 3.

8. The method according to any one of the preceding claims 1 to 7, characterized in that silazane is present in solution and the concentration of silazane in the solution is preferably 0.1 to 10 wt .-%, particularly preferably 2 to 10 wt .-%, is in which the solvent is in particular selected from the group consisting of aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, esters, ketones, ethers and mixtures of these solvents.

9. The method according to any one of the preceding claims 1 to 8, characterized in that the amount of the solution used for the application or the silazane solid is chosen so that the amount of silazane less than 5 wt .-%, based on the weight of textile fabric, amounts to.

10. The method according to any one of the preceding claims 1 to 8, characterized in that the amount of the solution used for the application or the silazane solid is chosen so that the silazane crosslinking product 1 g / m ² to 100 g / m ² basis weight of makes thermal insulation molding.

11. The method according to any one of the preceding claims 1 to 10, characterized in that the polysilazane solution contains a filler from the group of ceramic powders, wherein the filler is in particular selected from the group consisting of silicon carbide, silicon nitride, boron nitride, and metal oxides.

12. The method according to any one of the preceding claims 1 to 11, characterized in that the textile fabric is produced in that the reaction is carried out at a temperature above room temperature, in particular at a temperature of at most 250 ⁰ C.

13. The method according to any one of the preceding claims 1 to 12, characterized in that the curing of the silazane of the solution of silazane, a catalyst is added, which is selected from the group consisting of N-heterocyclic compounds, monoalkylamines, dialkylamines, trialkylamines, organic acids , inorganic acids, peroxides, in particular dicumyl peroxide,

Azo compounds, metal carboxylates, acetylacetonate complexes, metal powders and organometallic compounds.

14. molding, prepared by a process according to any one of claims 1 to 13, wherein the molding is in particular selected from the group consisting of a plate, a preformed molding and a thermal insulation molding, wherein a thermal insulation molding is particularly preferred and this is particularly preferred for Use in the automotive sector, in the installation technology or heating technology is provided.

15. Use of a silazane according to one of the formulas I, II or III for applying glass fibers and / or silicate fibers

wherein

(a) R ² and R ^{3 are the} same or different and are hydrogen or straight, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, aryl, arylalkyl, alkylaryl, alkenylaryl or arylalkenyl, wherein each of the substituents R ² and R ^{3 is} in the case of m and / or o greater than 1 in different units has a different or the same meaning,

R ² and R ^{3 are the} same or different and are straight-chain, branched or cyclic, substituted or unsubstituted alkyl, alkenyl, aryl, arylalkyl, alkylaryl, alkenylaryl or arylalkenyl, wherein each of the substituents R ² and R ³ in the case of n and / or o greater 1 in different units a different one Has meaning or the same meaning,

or

(i) all, or

(ii) one part each

the radicals R ³ and R ³ together represent an unsubstituted or substituted, straight-chain or branched alkylene group, in variant (ii) the remaining part of the radicals R ³ and R ³ having the meaning given under (a),

and in which

R ⁴ and R ^{4 '} Alky 1, phenyl or hydrogen, where a plurality of radicals R ⁴ and / or R ⁴ in each case one molecule of the compounds (I) to

(III) may be the same or different,

R ¹ and R ^{5 are the} same or different and may have the same meaning as R ² or R ³ , wherein R ⁵ in addition also

Si (R ') (R ^2' ) (R ³ ) may mean or R ¹ and R ⁵ together a

Represent single bond,

R ⁶ Si (R ² ) (R ^{2 '} ) -XR ⁷ -Si (R ² ) _q (OR ^2' ) _3-q wherein X is either O or NR ⁴ , R ^{7 is} a single bond or a substituted or unsubstituted one , straight-chain, branched or cyclic

Alky lengruppe represents and q can be 0, 1, 2 or 3,

P is an alkylene group having 1 to 12 carbon atoms, m and p independently represent an integer between 1 and 25,000, and

n and o are independently 0 or an integer between 1 and

25,000, where m, n, o and p are such that the silazane has a number average molecular weight of 150 to 150,000 g / mol, in particular from 1,000 to 5,000 g / mol, and wherein the units in square brackets uniformly, randomized or block-wise distributed in each molecule,

wherein a silazane is preferred, which is selected from the group consisting of the silazanes of the formulas V and VI and mixtures thereof, and in particular a number average molecular weight of 1,000 to 5,000 g / mol .:

(VI)