WO2011104010A2

WO2011104010A2 - Light paste-like refractory adhesives and their use

Info

Publication number: WO2011104010A2
Application number: PCT/EP2011/000874
Authority: WO
Inventors: Rainer Angenendt; Heike Meschke
Original assignee: Vatramaxx Gmbh
Priority date: 2010-02-24
Filing date: 2011-02-23
Publication date: 2011-09-01
Also published as: DE102010009145A1; WO2011104010A3; EP2539297A2

Abstract

The light paste-like refractory adhesives which harden when dried and which contain at least one light-weight filler, a binder, fibers and/or wollastonite and water are characterized in that an organic-inorganic binder (hybrid binder) is used as the binder, said binder containing finely divided silicic acid and an organic polymer. The material or the mortar contains white clay or kaolinite and silica gel, especially silica.

Description

Light pasty refractory adhesives and their use

The invention relates to adhesive according to the preamble of claim 1, in particular one-component high-temperature resistant ready-to-use light pasty refractory adhesive with immediate adhesion, which harden when dried and at least one

Light filler, a binder containing fibers and / or wollastonite and water, for applications up to about 1100 ° C.

The term lightweight fillers are to be understood here as high-melting mineral granules of low density, for example, expanded volcanic ash, expanded perlite, etc.

In the present application, "finely divided" or "fine" is not used in the sense of a certain small grain size, but in the sense of "powdery" or "granular" in contrast to "lumpy." So there is no specific one

Grain size or grain size distribution.

PRIOR ART Adhesives based on metal oxides and silicon oxide as well as are known

Glasses of water. These adhesives for temperatures up to 1000 ° C and higher have high densities of 1 - 2.8 g / ml and tend to shrink on drying, which can cause fine cracks. Also, a fixation of the products to be bonded is necessary.

Bonding of insulation materials for vehicle construction, shipbuilding, aircraft construction, building construction and industry, for bonding against molten metal in foundry technology The main application spectrum is fireproof bonding of mineral wool or other porous insulating materials on various absorbent or non-absorbent substrates, for example in shipbuilding, and in the field of shipbuilding rail vehicle construction. In shipbuilding, aircraft construction and rail vehicle construction is always looking for new lighter materials. In addition to the energy costs that every kilogram of material used consumes, every kilogram of material that is installed above the waterline is problematic, especially in shipbuilding, since this reduces the payload of a ship by one

Multiple (tilting moment) is reduced. On the other hand, especially in shipbuilding the Fire safety regulations extremely high, as there are no fast and safe escape routes on ships.

The adhesives according to the invention have, in addition to the adhesive, an insulating (low apparent density 0.250-0.350 g / ml) and optionally a cooling in case of fire

Function (elimination of water from minerals). This combination makes it possible to build thinner, lighter and safer fire protection structures with conventional insulation and fire protection materials. Document EP 1 508 602 A1 describes a high-strength assembly adhesive in order to be able to withstand greater loads.

Object of the invention and its solution

The invention has for its object to develop light pasty refractory adhesive of the type mentioned for cost-effective full-surface bonding of insulating areas, which only a very low shrinkage (<1%) and secure fixing of the insulating materials to be mounted or

1100 ° C, have a low bulk density of only 0.250 to 0.350 g / ml and, where appropriate, an in

Fire case containing cooling component.

This object is achieved according to the invention in the light pasty refractory adhesives of the type mentioned by the features of claim 1. Further advantages of the light pasty refractory adhesive according to the invention will become apparent from the comments below.

Comparison with the prior art

The document EP 1 508 602 A1 describes a mounting adhesive with a creamy consistency on an organic basis with any inorganic fillers. In fact, not all fillers are suitable for this at all. The recipes are kept very vague.

In contrast, according to the invention, a pasty adhesive with hybrid binders is described, wherein the organic fraction is based on an inorganic framework of silica sol grafted, so the organic portion forms a unit with the inorganic portion. In this way, the shrinkage and thus the destruction of the structure is counteracted in case of fire. Since the adhesive according to the invention is additionally mixed with binders of pure silica sols and mineral binders of silica which contains finely divided kaolin, the adhesive according to the invention retains its structure even at temperatures up to 1100.degree.

Document EP 1 508 602 A1 describes a high-strength assembly adhesive in order to be able to withstand greater loads.

According to the invention, however, an adhesive is described which is suitable exclusively for fixing lightweight insulating materials or for filling, jointing and coating and whose function is to protect the object in the event of a fire by obtaining the adhesive, coating, etc. Therefore, the content of organic adhesive components is very low (fire class and low energy release) and the inorganic and mineral adhesive components (high

Fire resistance) very high. The mineral adhesive component kaolin or kaolinite develops its adhesive power completely only at high temperatures of 500 to 1000 ° C, so that the product then obtains its final strength and high fire resistance. At these temperatures, the adhesive according to the

Document EP 1 508 602 Al long failed.

These differences to the adhesive according to document EP 1 508 602 A1 and the completely different applications show the novelty and the inventive content of the adhesive according to the invention.

Details of the invention

The meaning and function of the individual components of the light pasty refractory adhesives according to the invention are explained below.

The content of fibers and / or wollastonite serves to cohesion of the mass in the wet state. Wollastonite is predestined for combination with microcellular expanded volcanic rocks due to its coarse needle-like structure. The short needles of wollastonite and the microcellular bloated volcanic rocks easily penetrate into open porous layers and thereby reinforce the bond of the surfaces to be bonded together. The hybrid binder (s) provide cohesion after drying at temperatures up to about 200/400 ° C due to the organic constituent and at higher temperatures due to the sintering of the silica particles.

The kaolin used and the silica sol are also a binder, which develops its function at elevated temperature. Kaolin is also used at

Applications of the adhesive in the foundry industry as a seal against liquid aluminum.

The closed-cell lightweight fillers provide the necessary volume and a very low density compared to the state of the art. In addition to the kaolin, which splits off approximately 14% of water at 550 ° C, the glue can

Aluminum hydroxide are added. Al (OH) ₃ is the world's most widely used flame retardant (also known as ATH for "aluminum trihydrate"), which works by splitting off water, which already starts at 150 ° C, cooling and gas-diluting.

The microcavities are surface treated to protect against water attack in the plastic adhesives, thereby rendering the adhesives shelf stable. Advantageous embodiments of the invention are set forth in the subclaims.

Furthermore, the invention relates to the use of the aforementioned adhesive for various advantageous applications according to claim 8.

As lightweight filler, preferably expanded cellular volcanic rocks are used.

Perlite (English: perlite) refers to an altered (chemically and physically transformed) volcanic glass (obsidian) in the geosciences and thus belongs to the rocks. The so-called pearlitic structure here is about pea-sized

Glass beads formed. Perlite contains up to 2% water and has a density of about 900 to 1000 kg / m ³ (bulk density of crude perlite). By annealing to about 800 ° C to 1000 ° C, perlite inflates to the fifteen to twenty times its original volume and then has a bulk density of 50 to 100 kg / m ³ and a thermal conductivity of λ = 0.040 to 0.070 W / mK. Microcellularly expanded volcanic rocks, produced using new environmentally friendly and energy-saving processes, achieve properties and technical values that distinguish them from older, porous expanded volcanic rocks ("expanded perlites"). Microcellular expanded volcanic rock is a filler from the group of aluminum silicates and is composed of spherical ("honeycomb"), rod-shaped and flaked particles, resulting in high packing densities and higher bond strengths than conventional hollow microspheres due to mechanical and cohesive bonding forces. targeted

Surface coatings enable an advantageous bond with the inorganic or organic matrix. This results in less shrinkage and better technical properties.

Commercially available is blown impregnated perlite z. B. under the

Trade names NOBLITE® (product of NOBLITE, Route de Claye, F-77181 LE PIN, France) and Technoperl® (product of Europerl Germany D-94032 Passau, Nibelungenplatz 4).

The expanded volcanic rock is preferably used in the form of nonporous hollow granules. It is also proposed that the expanded volcanic rocks consist entirely of cellular expanded volcanic rocks. For porous

Hollow granules would increase the bulk density, due to the increased need for binders and minerals (infiltrate). The masses would be dull and would be worse to process. According to the invention, the mass after hardening is extremely stable, even at 1000

° C virtually no shrinkage, no external or internal cracks and is for

Continuous temperatures up to 1000 ° C suitable.

Kaolin, also referred to as china clay or aluminum silicate, is a fine, iron-free, white rock containing kaolinite, a weathering product of feldspar, as the major constituent.

The kaolin used as a film covers the high-melting light filler and additionally solidifies the structure of the adhesive at 550 ° C and 970 ° C. The strength of the structure and the shrinkage are determined by the ratio

Kaolin Siliceous / KieselsoiyAluminiumhydroxyd to the light fillers and their distribution influenced. Another advantage of the used mixture of kaolin / silica sol and / or silica is that the mass after drying in addition to the binder, the fibers and or wollastonite is mechanically stabilized.

It is also proposed that a binder mixture of several

Binders is used with a binding effect in different temperature ranges. The innovation of the product according to the invention also consists in that suitable, complementary binder systems are used, for. B. the hybrid binder, which adheres the support structures made of fibers and / or wollastonite already during drying under room temperature with the light fillers (microcellular expanded volcanic rock) sufficiently to fix the structure. By mineral binders, z. As kaolin and silica sol and / or silica, which are already finely divided, and the silica contained in the hybrid binder, this structure is sufficiently strong solidified even in temperature ranges above 300 ° C. At about 550 ° C, the structure is solidified again by the reaction of kaolinite in metakaolin. From about 970 ° C, a further solidification of the adhesive by conversion of metakaolin in spinel and quartz. At temperatures above 1100 ° C, the lightweight fillers melt and thereby reduce the volume of the adhesive, but the bond itself remains above 1100 ° C. It is particularly innovative that the different binders and the high-melting mineral granules complement each other with regard to the solidification of these materials when the temperature rises so that a dimensionally stable and constant weight product with high strengths up to the maximum

Application temperature arises.

Fibers used according to the invention

In particular, ceramic and / or mineral refractory fibers and / or organic refractory fibers, for example carbon fibers, alone or in

Combination with wollastonite used. Preferably, wollastonite is used. Wollastonite (rarely also tablespar or tablespat) is a frequently occurring mineral with the chemical composition CaSi0 ₃ , more precisely Ca ₃ [Si ₃ 0 ₉ ]. From a chemical point of view, wollastonite is a calcium salt of metasilicic acid and therefore belongs to the mineral class of silicates. Based on

Crystal structure can explain some macroscopic properties of wollastonite. Monocrystals of wollastonite have a needle-like to fibrous form

(Habitus), because the crystals preferentially grow in the direction of the crystallographic b axis, which corresponds to the orientation of the silicate chains in the crystal structure. If a wollastonite needle breaks through in the middle, that is, the silicate chains are broken, uneven fracture surfaces result, while under mechanical stress, even split surfaces are created parallel to the b axis. This can also be explained by the chemical bonding conditions in the crystal. While silicon and

Oxygen via covalent bonds (atomic bonds) are interconnected, there is an ionic bond between calcium and oxygen, which is based on a purely electrostatic interaction and thus represents the weaker bond. Due to its fibrous to needle-like crystals and its high melting point (1540 ° C), wollastonite offers a wide range of technical applications (source:

Wikipedia). Ceramic fibers or ceramic fibers are fibers

inorganic, non-metallic material. Originally, only polycrystalline inorganic materials were called ceramic. However, there are now various polymers, so-called precursors, produced by pyrolysis amorphous fibers, which are referred to by their properties as ceramic fibers. The distinction to amorphous glass fibers, which are not counted among the ceramic fibers, is best made possible by the manufacturing process (glass fibers from glass melt, amorphous ceramic fibers from polymeric precursors by pyrolysis). The ceramic fibers are classified into oxidic and non-oxidic. On oxide ceramic fibers are fibers based on alumina and

Silica in different proportions and in part still with additional boron oxide or zirconium oxide known. Mixed oxide fibers of 85% A1 ₂ 0 ₃ and 15% Si0 ₂ are also referred to as mullite fibers. All of these fibers are polycrystalline. Non-oxide, industrially produced fibers (other than carbon fibers) have various types of silicon carbide fibers known. Starting polymers are almost exclusively so-called poly-carbosilanes. These are polymers Hydrocarbons in which individual carbon atoms have been replaced by silicon atoms or silanes in which individual silicon atoms have been replaced by carbon atoms. Additives crosslink the polymers in a curing process, so that they do not simply evaporate after the spinning process during the pyrolysis, but - as in the production of carbon fibers - are converted into an amorphous, usually non-stoichiometric, still free carbon-containing SiC ceramic fiber. In special manufacturing processes, it is also possible to produce very finely crystalline and pure SiC fibers with significantly improved high-temperature properties.

Hybrid bonding agent used according to the invention

Preferably, an organic-inorganic hybrid binder is used, which is available under the trade name COL.9 BASF and Inowool W + from the company Inomat. COL 9 contains 50 to 100 nm composite particles containing amorphous silica particles 5 and a polymer 6 based on n-butyl acrylate and methyl methacrylate (see Figure 1). The particles are dispersed in water. Due to the stickiness of the particles due to the polymer content is obtained an excellent binder for low temperatures, up to about 200 ° C. At elevated temperatures, the polymer fraction decomposes and the silica particles remain and thus preserve the structure, wherein the silica particles also forms a solid framework at a correspondingly high temperature. This also applies to the binder "inof lamb base." In this case, the polymer is an alkyl-modified polysiloxane, and shrinkage therefore does not occur at low or elevated temperature Both binders have a solids content of about 35 to 60% by weight. proportion, based on the solids content, is 30 to 60 wt .-%.

Silica used according to the invention

Preferably, a surface-treated silica is used. Silica is an intimate mixture of finely divided silica and kaolinite. For example, the Neuburg Siliceous Earth is known, which is preferably used according to the invention. For better wettability with water, the silica is treated with a silane so that the individual particles have a functional hydrophilic surface. Such an activated silica is available under the trade name "AKTISII EM" from Hoffmann Mineral GmbH, Neuburg (Danube), where the silica is treated with 3-epoxypropyloxipropyltrimethoxysilane.This so-called activated silica can be used in powder form the use of a mixture of silica sol and kaolin / kaolinite.

example recipe

for 100 kg light pasty refractory adhesive:

Microcellular flowered volcanic rock "Noblite 200 EC"

the company Noblite 30,00 kg binder "Inowool W +" of the company Inomat 14,00 kg

Silica "Aktisil EM" from Hoffmann Mineral 7.00 kg

Surface-modified wollastonite flour "Tremin-300 EST"

the company Quarzwerke 7.00 kg

Surface-modified aluminum hydroxide "Trefil 744-300 EST"

quartz works 5,00 kg loose Rockwool Rockwool 3,00 kg

Binder "COL. 9 "from BASF 3.00 kg

Water 31.00 kg Production example for light pasty refractory adhesive

All liquid components of the formula are accurately weighed and carefully mixed to avoid foaming. Simple toothed disc stirrers have proven themselves here in practice.

The precisely weighed fibers are carefully added to this mixture, teased by stirring (at low speed) and completely wetted with the aqueous solution.

Thereafter, the precisely weighed light fillers and minerals are mixed with each other in a free fall mixer. Both premixes are mixed together with uniform slow stirring in a compulsory mixer for about 45 min. High shear forces, pressure and friction are to be avoided as much as possible in order not to damage the microcellular bloated volcanic rocks. The lightweight fillers must be completely wetted to obtain a homogeneous lightweight pasty adhesive.

Special advantage

A central customer benefit when using the products according to the invention is the desired goal of more efficient and safe fire protection

Simultaneous weight saving with simple and safe processing. Further important advantages of the invention are:

• Low weight

• High adhesion even on porous materials

• High temperature resistance

• Low thermal conductivity

· Good strength properties

• Easy installation and processing

• Many combination options

• Low flue gas development

• Low alkalinity

· High chemical resistance

• Recyclable

• Landfillable Use according to the invention The adhesives according to the invention are preferably used for the bonding of

Mineral wool or other porous insulating materials used on absorbent or non-absorbent substrates.

The fields of application are the industrial furnace construction, the foundry technology, the

Shipbuilding, aircraft and vehicle construction, industrial power plant and plant construction, rail vehicle construction, building construction and technical heat insulation.

In particular, the light pasty refractory adhesive according to the invention for the o. G. Bonding of mineral fiber insulating materials to metal or other non-absorbent and absorbent substrates is particularly well suited.

The paste-like, light-weight structure of the adhesive enables it to adhere to almost any surface, while at the same time allowing the adhesive to be incorporated into porous surfaces. Due to the resulting high capillary forces, the light pasty refractory adhesives can also be used on porous and absorbent substrates.

From the different application and processing possibilities of the

adhesive according to the invention results in a tremendous number of possible uses, which are summarized here, without claim to completeness, in a nutshell:

· Cable / pipe bulkheads,

• joint seals,

• closing holes and cracks in walls and ceilings,

• fire protection seals,

• coatings for exhaust systems, heat shields, electrical appliances,

Motors, ovens and grills,

• repair of fireplaces,

• Wall and ceiling coatings

• spray plaster on reinforced concrete structures,

• Spray plaster coverings.

Claims

claims

Pasty refractory adhesive, which hardens when dried and at least

a lightweight filler,

a binder,

- fibers and / or wollastonite,

- Water

contains

characterized,

that as a binder one or more organic-inorganic

Hybrid binders are used which contain silica and an organic polymer that the adhesive contains kaolin and / or kaolinite, that the adhesive contains silica and / or silica sol.

Adhesive according to claim 1,

characterized,

that the hybrid binder contains particles which in turn are composed of amorphous silica particles (5) containing as binder a polymer (6) based on acrylate, in particular n-butyl acrylate and

Methyl methacrylate and / or alkyl-modified polysiloxanes.

Adhesive according to claim 1,

characterized,

that a modified silica is used which contains silica-kaolinite particles whose surface is coated with a wetting agent, in particular a silane.

4. adhesive according to claim 1,

characterized,

that as light filler blown closed cell volcanic rock is used.

5. adhesive according to claim 4,

characterized,

that the expanded, closed-cell volcanic rock is surface-treated. Adhesive according to claim 1,

characterized,

that a uniform type of fibers or a mixture of different fibers and / or WoUastonit, in particular surface-modified wollastonite, with softening points of at least 950 ° C are used.

Adhesive according to claim 1,

marked by

the following composition

Light filler 20 to 40% by weight

Hybrid binder 10 to 25% by weight

Fibers Obis 7Gew .-%

WoUastonite 0 to 15% by weight

modified silica or silica sol 0 to 30% by weight

further mineral fillers 0 to 20% by weight

Rest of water

8. Use of the light pasty refractory adhesive according to claim 1 as a high temperature adhesive, to support fire protection and / or thermal insulation, as a filling material or for sealing small cavities or for coating wall surfaces.