DE2434445A1 - INORGANIC FELT PRODUCTS - Google Patents

Description

PATENT LAWYERS DR.-ING. H. FINCKE DI PL-ING. H. BOHR DIPL.-ING. S. STAEGER

Long-distance call: '26 60 60 Telegrams: Claim »Munich Postal checking account: Munich 27044

Bayor bank details. Association bank Mönchen, account 620404 -

MUNICH 5. M0llerstrasse 31

Folder No. 23574 "

Specify BiHe in the answer

ICI CASE MD 26301/26818

IMPERIAL CHEMICAL INDUSTRIES LIMITED

Imperial Chemical House,

Millbank

London S.W.1 / UK

"Inorganic mushroom products"

PRIORITY

British patent no. 33917/73 of July 17, 1973 and

British patent no. 8367/74 of February 25, 1974

• x * * * *

The invention relates to inorganic felt products, and in particular on felt products, which are composed of inorganic fibers and an inorganic binder.

According to the invention a method for the production of proposed inorganic felt products, which is carried out by an aqueous dispersion, the synthetic

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table polycrystalline inorganic fibers and a colloidal one contains inorganic binder, produces and then removes the water from the dispersion, the felt product is formed.

The surface characteristics such as roughness and the surface charge, of synthetic polycrystalline inorganic fibers can be controlled more easily and more precisely than those of vitreous or natural inorganic fibers, creating a better opportunity is to bring about a sufficient bond between the fibers and the inorganic binder without one Must use fibers with a very rough surface. Excessive surface roughness is common in the manufacture of Felt products according to the invention undesirable because the fibers then too easily through mutual contact in the Dispersion can be damaged, which leads to degraded fibers. In addition, polycrystalline fibers can be controlled with Surface and porosity can be produced, so that there is another advantage in terms of proper absorption of the binder into the fiber, so that a good anchorage is obtained.

By the term "felt product ¹¹ is meant a cohesive mass of non-woven fibers. It is generally in the form of paper, cardboard, blanket, felt, wadding, mat or shaped article, especially tubes, corrugated or ribbed. ***" Plates or perforated matrices.

Preferably, the polycrystalline inorganic fiber is a refractory fiber because then the felt product for applications with high! temperatures can be used. Preferably the refractory fibers are polycrystalline metal oxide fibers, especially those made of aluminum oxide, zirconium oxide,

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Titanium oxide, silicon oxide and thorium oxide, as these are particularly heat-resistant. Alumina and Zirconia Fibers are particularly suitable.

Synthetic polycrystalline inorganic fibers are useful by making a sol or a Solution, preferably an aqueous sol or an aqueous solution, of a salt or other compound contained in the material from which the fiber is made can be converted into fibers. Suitable processes are described, for example, in GB-PS 1,098,595. The mentioned Fibers are particularly suitably made by those processes in which the above-mentioned sol or the above-mentioned solution additionally contains a dissolved organic polymer, in particular a linear organic polymer, contains. Such methods are described in British Pat. ! 9909 / 70- ^ 369/71 described, (published as Dutch. Patent application No. 7 108 399), the details of which are to be considered included in the present description. at According to these methods, fibers are made by using a composition having a viscosity greater than 1 poise is processed into fibers made from an aqueous solution or an aqueous sol of a metal compound such as e.g. an oxychloride, basic acetate, basic formate or nitrate of a metal, in particular aluminum and / or zirconium and a smaller amount of a water-soluble organic polymer, preferably polyethylene oxide, polyvinyl alcohol or polyvinylpyrrolidone, after which the fiber produced is dried and heated to obtain the Metal compound in the oxide and the polymer to decompose.

For the process according to the invention, it is preferred to use inorganic Use fibers that are small in diameter, such as an average diameter

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from 0.5 to 5.0 / rev. The pasers should in particular have a narrow range of diameters, such as, for example, a range such that at least 90 % of the pasers have a diameter in the range from 2 to 4 / u. own. It is also preferred that the fibers in the dispersion have a length of at least 0.5 mm, preferably 0.5 to 25 mm. In the method according to the invention, it is advantageous to use a material which is largely free from shot, that is to say a material with a non-fibrous nature. The use of relatively straight fibers supports the dispersion in water.

Inorganic fibers having the above-mentioned desirable properties of small and uniform diameter Minimal length, shot-free and straightness are conveniently obtained by a blow molding process like that in British Patent Am. No. 29909 / 70-4369 / 71. This procedure consists of having an in Composition that can be processed, such as one as described above, through one or more holes, which preferably have a diameter of 50 to 500 / u have, extruded in at least one gas stream, which is a component of high speed in the direction of travel having extruded composition. It is convenient to use two gas streams, one at or near the extrusion point converge, preferably at an angle of 30 to 60 °, so that the fibers are pulled down. The rate of water removal from the composition is conveniently controlled by keeping the gas mixes with steam. For example, air with a relative humidity greater than 80 # can be used.

The inorganic binder can be preformed in the dispersion Colloid or preformed sol, or as one in one

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Colloid transferable soluble material are incorporated, the necessary conversion by a suitable treatment of the fiber dispersion, for example by hydrolysis and / or heating. Materials in Colloids are convertible, are expediently from oxychlorides or basic inorganic salts of metals are selected, which are converted into metal oxide sols on heating. Oxychlorides, basic acetates or basic formates of aluminum and / or zirconium are particularly preferred. Inorganic silicates, such as sodium silicates, are useful because, for example, by acidification they are converted into colloidal Silicon oxide can be transferred.

Preferred colloidal inorganic binders for use in accordance with the invention are hydrated oxide sols of alumina, silica, titania, zirconia or a mixture of two or more of these. All of these form refractory oxides when heated so that temperature resistant mushroom products can be made therefrom. Silica sols available from NALFLOC LIMITED under the names "Syton", "Ludox" or "Nalcoag" (under order numbers N1030 and N1050) are particularly suitable. Alumina sols and alumina hydrate sols (boehmite) sold under the names "Baymal" or "Cerasol" are more preferred. Particularly suitable fiber-forming boehmite sols, which can be prepared according to GB-PS 893 852 or 1,029,421, are commercially available under the names "GC Powder" (CAWOOD WHARTON & COMPANI LIMITED) or "Balgel" (AERE, Harwell, England) .

It has surprisingly been found that, despite the fact that the particles in the fiber-forming boehmite sols are positively charged, they result in a particularly good bond of the metal oxide fibers, which are also positively charged. A particularly good combination of fiber and binding

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Medium are aluminum oxide and / or zirconium oxide fibers, which can be obtained by the blow molding process described above are, and fiber-forming boehmite sol, because the binding is then special runs well and the mushroom products made from them are strong and tough and easy to handle.

Organic binders can optionally be present in the aqueous dispersion of the polycrystalline fibers, such as e.g. vinyl or acrylic materials, water-soluble polymers, such as starch or cellulose derivatives, thermoplastic resins or thermosetting resins such as phenol / formaldehyde resins ...

Optionally, fillers can be added to the aqueous dispersion may be added, such as clays such as kaolin and bentonite or puffed mica. Other organic or inorganic fibers than the synthetic polycrystalline fibers, such as glass fibers, cellulose fibers or uylon fibers, can also be present in the dispersion. Organic fibers can optionally be removed from the finished felt product by burning it out.

The aqueous dispersion can be made by an appropriate dispersing technique getting produced. Appropriate processes are e.g. those used for the production of paper and Cardboard can be used. Dutch bats or pulpers can be used appropriately. Usually the The fiber is beaten or otherwise dispersed for a sufficient time to produce a uniform dispersion. It is a particular advantage of polycrystalline fibers and especially of polycrystalline alumina and alumina Zirconia fibers that such fibers are not broken into excessively short lengths when passed by a conventional one Dispersion technology are treated. The binder

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(and other optional additives) can be added at any convenient stage, preferably during or after the dispersion method. Too long beating, which excessively shortens the fiber length, should preferably avoided. The concentration of the polycrystalline inorganic fibers in the dispersion can be can be varied within wide limits, but it is usually in the range of 0.05 to 2.0 parts by weight each 100 parts by weight of the dispersion. For papers with a low basis weight, the preferred concentration is Fibers in the dispersion 0.1 to 0.5 part by weight per 100 parts by weight of the dispersion. For products with a high basis weight concentrations of 0.5 to 1.0 part by weight are preferred. The concentration of the colloidal inorganic binder can also be varied widely, but is normally 0.002 to 2.0 parts by weight per 100 parts by weight of Dispersion.

It is usually advantageous to use a dispersant add to facilitate the dispersion of the fibers. Preferred dispersants are salts of low molecular weight polymeric carboxylic acids and sodium hexametaphosphate. When the pH of the dispersion is kept at about 3 to 7 the dispersion of the fibers is thereby also supported.

TJm loss of binder in the subsequent water removal To keep from the dispersion low, it is preferred to use the colloidal binder and optionally also the organic Precipitate or coagulate binder after dispersion is complete. This can be expedient can be achieved by adding acid and / or alum to the dispersion.

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A retention aid can optionally be used in the dispersion be present to increase the pest control of the binder and any filler that may be present and prevent migration of the binder in the felt product. A preferred retention aid is a high molecular one (for example more than 20,000, preferably more than 100,000) polyacrylamide, especially a straight-chain one Polyacrylamide. Partially hydrolyzed polyacrylamide can be used, which optionally contains other comonomers.

Initially, water is preferably removed from the dispersion by a suitable mechanical dehydrator. The usual methods can be used, such as draining from a pourdrinier sieve, from rotary machines, such as the "Rotoformer" or the "Hydroformer" Drum machines and from machines with inclined wire nets. Any suitable vacuum forming technique can also be used be used. Papers and cardboard are expediently produced by the fact that the liquid can run under the force of gravity or under a slight negative pressure (suction) on a wire mesh. Thicker and three-dimensional mushroom products or those with complex porms are preferably processed by a Vacuum forming technique, generally using a higher negative pressure. Cylindrical felt products with open ends can be conveniently made thereby be that the dispersion is dehydrated on a wire cylinder. Cylindrical products with a closed The end can be made on a wire cup. Paper, cardboard, and other flat products can all be on one Wire mesh can be couched in the usual way, such as using a couch felt. It. is a special one Advantage of mushroom products made from polycrystalline aluminum oxide and zirconia fibers have been manufactured so that such products have a uniform and easily controlled

- 409888/1006

manageable thickness and a substantially smooth surface texture exhibit"

The products can optionally be pressed before further drying, for example under a pressure of up to to 7 at. The absence of shot in the polycrystalline fibers used makes this possible, namely at Paper pinholes arise when there is grist in the fibers be subjected to other beneficial treatments. For example, further binders can be added or the product, in particular a paper, can be brought into the desired shape, e.g. by rib formation (where expediently the paper is passed through a pair of intermeshing corrugated rollers), embossing or molding.

After draining, and after carrying out any process "is still wet while the product, as described above, the wet product is dried, preferably by heating the product to a temperature at which the water evaporates, for example, 60 to 170 ⁰ C,

The dried products can then already be used, but they are preferably made further refractory by ^{firing them, for example at a temperature of 500 to 2000 °} C. The firing removes the organic material which is used in this process . In addition, desired changes can take place in the inorganic materials, such as decomposition to more refractory compounds, phase changes or sintering.

The invention also relates to felt products made from synthetic consist of polycrystalline fibers and an inorganic binder.

4 0 9 3 8 6/1006

The synthetic polycrystalline fiber is preferred a metal oxide fiber, particularly a refractory metal oxide fiber. Alumina and / or zirconia fibers are most preferred, especially when made by a process as disclosed in U.S. Patent No. 5,214,211 British Patent App. JJr. 29909 / 70-4369 / 71 is described. Fibers with average diameters from 0.5 to 5.0 / U are preferred, especially fibers that fall within a narrow range of diameters, such as such that at least 90% of the fibers have a Diameter from 2 to 4 / u. exhibit. It is very preferred when the fibers are largely free of grist.

The inorganic binder is preferably selected from silica, zirconia, titania and alumina. At the Most preferred is a fiber-forming boehmite binder, especially if it is used to bind aluminum oxide and / or zirconia fibers produced by the above-mentioned blowing method is used.

The proportions of polycrystalline fibers and inorganic binder in the dry product can vary widely, for example from 5 to 99 parts by weight of polycrystalline Fibers and from 1 to 95 parts by weight of binder per 100 parts by weight dry product. The products with the most versatile applications contain 10 to 80 parts by weight of a polycrystalline Fiber and 10 to 50 parts by weight of a binder per 100 parts by weight of dry product. A particularly useful paper product contains 80 to 90 parts by weight of fibers and 10 to 20 parts by weight of a binder per 100 parts by weight of dry Product. The above values for molded parts deformed by vacuum, such as perforated matrices, are between 50 and 80 parts by weight for the fibers and 20 to 50 parts by weight for the binder per 100 parts by weight of dry product.

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The products described here "can be used for many different purposes Applications are used. So can paper and cardboard for thermal insulation, the handling of melted Metals, the piltration of hot gases, molten metals and corrosive liquids, electrical insulation and seals are used. Molded parts such as rods, tubes, honeycombs and corrugated or folded structures are suitable for hot chimneys, conveyors in glass bottle production, electrolytic cell separators, electric Battery components, catalyst carriers and many other applications where heat resistance and chemical inert, are important.

Vacuum formed or cast moldings based on refractory fibers according to the invention are particular Useful products as they are lightweight and have excellent heat insulation and fire resistance a good stiffness. Another useful property of this molding process is the ease with which it is made of complex structures can be produced.

One of the special uses for these products is as an insulating refractory lining for ovens and other heated Structures. Tubular and box-shaped parts for small ovens or plates for larger ovens can easily getting produced.

Many such structures are electrically heated and require support for the heating elements. Such supports can be vacuum formed or cast according to the invention in at least three ways manufactured, such as:

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1) A groove or notch for the heating element (wire or rod) can easily be cut into the shape after the latter has been made, conveniently uses a simple tool such as a razor blade, knife, or scalpel will.

2) The notch or groove can be worked into the molding, while it is being manufactured using an appropriate mold in which the groove is provided is. The heating element is placed in the groove after the mold has dried and possibly also fired has been. ·

3) The entire heating element (wire or groove) can be in the molding can be incorporated at any suitable stage during its manufacture. For example A small tubular chamber of a muffle furnace can be made by making the fiber dispersion into a cylindrical shape, the molding process at any point during the build the wall thickness interrupts, winds a wire on this element and then completes the vacuum forming operation. The element is thus firmly incorporated into the furnace lining and in the vicinity of the hot surface, so that the thermal insulation between the element and the furnace chamber is low.

When the heating element is placed in a groove or notch that is cut or molded into the molding then it can either remain exposed on the hot surface of the molding or with a strip, a slurry or a pourable cement to hold the element in place or to remove it to protect mechanical or abrasion damage.

409886 / 100.6.

The techniques described here can be applied to the most varied of product types. Small laboratory muffle ⁱ to large linings of industrial furnaces can be prepared in a similar manner although it is more convenient in the latter case the lining of flat ironing is produced and does not consist of complex-shaped, produced by vacuum forming parts.

Another application is thermal insulation on pipes of method, with the heating elements in wraps can be incorporated, which greatly simplifies assembly. Flask heating hoods can be used in the laboratory. can be produced more easily by forming the insulation and the heater as a single block. Household heating plates can be provided with a pre-formed carrier insulation or the elements can be incorporated into a heating pad while central heating radiators can be made from sheets of the felted products in which the heating elements are embedded.

Densities of the mushroom products of the invention can be strong can be varied. Products with densities from 0.35 to 3.5 kg / cm are usually produced;

The invention is further illustrated by the following examples, in which all parts are expressed by weight, unless otherwise stated.

B e is ρ IeI 1 .

Alumina fibers with diameters ranging from 0.5 to 5yU were prepared as follows: 50 ml of an aluminum oxychloride solution, The 11.2 wt .- # Al and 8.1 wt .- 5ε Cl contained, with 30 ml of a 2 # (weight) solution of a

100 8

mixed with high molecular weight polyvinyl alcohol. The mixture was concentrated to a viscosity of 50 poise by evaporation under reduced pressure. The concentrated solution was introduced into a fiber blowing device into which two rapid streams of air were introduced from both sides and at an angle of 30 ° to the flow of the solution which was under pressure came out of a hole with a width of 25 / u _{r met} . The air streams had a temperature of 35 ^° C. and a relative humidity of 40 °.

A mat of very fine fibers with lengths up to 10 cm and diameters of about 1 / rev was collected on a hedge. The mat was ^{heated to 800 °} C. for 1 hour, with clear, glassy fibers being obtained which were silk-like and flexible.

40 parts of aluminum oxide fibers, which had been produced according to the above procedure, were introduced into 20,000 parts of water, which were located in a standard laboratory float. 8 parts of an acrylic latex ("Revertex" A272 ex Revertex Limited) with a solids content of $ 55 and 14 parts of a colloidal silicon oxide sol with a solids content of $ 35 were added to this dispersion.

A 10 # (w / w) alum solution was added under mild Stirring was added to bring the pH of the dispersion to 4 »5 bring to.

Then, 12 parts of a solution of a high molecular weight polyacrylamide ( "MagnafloD ¹¹ £ 292 ex Allied Colloids) st with a fixed off gehält of 0.20 i" (wt. / Wt.) Was added and then on a sieve in a laboratory paper former paper was produced.

The paper was removed from the screen and squeezed "dried at 10O ⁰ C. The paper was then 10 min." Fired at 800 ⁰ C. The paper, dried at 100 ° C. but not fired, had a basis weight of 200 g / m 2, a density of 16 g / cm 3 and a tensile strength of 0.35 kg / cm.

example

Zirconium oxide fibers with a diameter in the range from 0.5 to 4 / U were produced as follows: A solution for the production of high-temperature resistant, yttrium oxide stabilized zirconium oxide fibers, which are particularly suitable for thermal insulation, was made from 500 g of zirconium acetate solution (22 # ( W / W) ZrO ₂ ), 220 ml 1 # (w / w) polyethylene oxide solution, 12.8 g yttrium chloride hydrate and 2 ml concentrated hydrochloric acid.

The solution was evaporated on a vacuum rotary evaporator to a viscosity of 15 poise at 20 ⁰ C and placed in a container with a spinning hole with a diameter of 25 / u. was equipped.

High velocity air jets exiting through slots on either side of this hole and at an angle of 30 ° converged, pulled a thread out of the liquid from the hole, so that one essentially shot-free fiber was obtained.

The fibers were ^{dried at 20O 0} C for 1/2 hour.

40 parts of zirconia fibers (prepared as described above) were placed in 20,000 parts of water in a laboratory beater dispersed.

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8 parts of a styrene / butadiene latex were added to this dispersion ("Breon" V 6480) with a solids content of 50 # and 80 parts of fiber-forming colloidal boehmite sol having a solids content of 5 # was added.

A 10 # (w / w) solution of alum was added under added mild stirring to bring the pH of the dispersion to 4.5.

Then 12 parts of a solution of a high molecular weight polyacrylamide ("Magnafloc ¹¹ R292) having a solids content of 0.20 # (w / w) were added, after which a paper was then produced on a laboratory paper former.

example

40 parts of aluminum oxide fibers (prepared as described in Example 1) with a diameter of 0.5 to 5 / U were in 20,000 parts of water, the pH of which was adjusted to 4 with hydrochloric acid, dispersed.

8 parts of an Acrylaltex ("Revertex" A272 ex Revertex Limited) with a solids content of 55 Å and 14 parts of a colloidal silicon oxide sol with a solids content of 35 Å were added to this dispersion.

A 10 # (w / w) alum solution was added under moderate Stir added to bring the pH of the dispersion to 4.5.

Then 12 parts of a solution of a high molecular weight polyacrylamide (»Magnafloc ¹¹ R292 ex Allied Colloids) with a solids content of 0.20 # (w / w) were added and a paper was placed on a sieve in a laboratory paper

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former manufactured.

The paper was removed from the sieve, pressed out and ^{dried at IQO 0} O * Bas Papier wandle gutm W BKiL. Fired at 800 ^° C. The dried, unfired paper possessed a

vent 200 g / m% a density -sram Ö »t5 g / ear and

a tensile strength of 2.1. kg / cm *

BeIa ρ i e 1

4 ©> geile ftTT> mfwfTwn-eaqraJtaggEB: 'CfeeggestfeLlt as in example 1 bescitriebeit) mdlt diameters from Q "5 to 5 / U were in 2O QOÖ iPeileBt water cliapergiert: “The 15 parts of a 40 # CSew /./ Wol ») PoijacrylaBiidl-bispersant (" Dispex "A40 ex Mliei G ^ ll & iäs) Entdelt

this dispersion were added 8 ropes of an acrylic latex { "KerrerteaE * 4272 ex. Eevertex Mmited) eiaes with a Feststoffgeüialt of 55 2 £ ναιϋί 14 Oieile colloidal Siliciumntit a solids content of 55% was added.

Was it a 10? S ^ ig © CSew./Öew;^^ Haunlösung added with moderate stirring, almost the pH of the dispersion to 4.5

Now there were 12 parts of a solution of a high molecular weight

{«MsgaaflQC * E292 ex Allied Colloids) with Solid content of 0.20 # (w / w)> added, whereupon a paper on a sieve in a laboratory paper former was produced.

The paper was removed from the sieve, pressed and dried at 100.degree. C. The paper was then tO min . 800 ⁰ Cr burnished. The unfired, dried paper possessed a. Basic weight of 2QO g / cm \. A density of 0.15 g / cm and a tensile strength of 1.4

example

40 ropes of zirconium oxide fibers (! Manufactured as in example 2 described) with a burcia knife from 0.5 to 5 / rev dispersed in 20,000 parts of water in a laboratory beater «

To this dispersion were 8 parts of an acrylic latex ("Revertex" A272) with a .Peststoffhalt of 55 S *, 14 parts of a colloidal silicon dioxide sol ("Nalcoag" ΙΓ1030) with a solids content of 35 i> rand 40 parts of fine kaolin (type of paper) admitted.

A 10 # (w / w) alarm solution was added under moderate Stir added to bring the pH of the dispersion to 4.5 bring. -

Then, 12 parts of a solution of a high molecular weight polyacrylamides ( "Magnafloc." R292) were mixed with a solid content was added from 0 _f 20 i »{wt .- / wt.) And a paper was prepared on a screen in a laboratory paper former.

The paper was removed from the sieve, pressed out and put at 10Q ° C]
burned.

100 ° C dried. The paper was then 10 min. At 800 ⁰ C

2 The paper obtained had a basis weight of 200 g / cm

and a tensile strength of 14 kg / cm. The tensile strength

after it was burned. 10.5 kg / cm.

B e 1 s ρ i β 1

40 parts of aluminum oxide fibers (produced as in Example 1 described) with a diameter of 0.5 to 5 * in 20,000 files of water in a laboratory racket in the usual

Chen way dispersed.

8 parts of an acrylic latex were ( "Revertex ¹¹ A272) was added with a solids content of 55%, 14 parts of a colloidal Siliciumoxydsols content of 35 $> and 40 parts Bentoni't with a Peststoff to this dispersion.

A 10 #ige (wt./wt.) Solution of alum was added with moderate stirring to bring the pH of the dispersion to 4 ». 5

Then, 12 parts of a solution of a high molecular weight polyacrylamides ( "Magnafloc" R292) having a Peststoffgehalt of 0.20 i "(wt .- / wt.) Was added, and a paper was prepared on a screen of a Laborpapierformers.

The paper was removed from the wire, pressed and dried at 100 ⁰ C. The paper was then fired 10 min. At 80O ⁰ C. The paper obtained had a basis weight of

2 2

200 g / cm and a tensile strength of 14 »7 kg / cm before

Burn. The tensile strength after firing was 17.5 kg / cm

Example 7

40 parts of aluminum oxide fibers with a diameter of 0.5 to 4 / U were in 20,000 parts of water in a laboratory beater dispersed in the usual way.

To this dispersion were added 8 parts of an acrylic latex ("Revertex" A272) with a pesticide content of 55 #, parts of a colloidal silica sol ("ITalcoag" N1030) with a pesticide content of $ 35 and 40 parts of kaolin (paper-making grade).

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A 10 # (w / w) alum solution was added under moderate Stir added to bring the pH of the dispersion to 4.5.

Then 12 parts of a solution of a high molecular weight polyacrylamide ("Magnafloc" R292) with a solids content of 0.20 56 (w / w) was added and then a Paper made on a sieve of a laboratory paper former.

The paper was removed from the wire, pressed and dried at 100 ⁰ C. The paper was then baked ^{at 800 ° C. for 10 minutes.} The paper obtained had a basis weight of

2 2

200 g / cm and a tensile strength of -15.4 kg / cm before Burn. The tensile strength after firing was 8.4 kg / cm,

Example 8

75 parts of zirconia fibers 0.5 in diameter up to 4 / U were in 18,000 parts of water in a laboratory racket dispersed. 15 parts of a fiber-forming boehmite sol (as a 5 # dispersion) were added to this dispersion. was added, followed by the addition of a 10 # (w / w) alum solution to bring the pH to 4.5 bring.

A paper was made on a screen former and dried to a moisture content of 75% by weight. That Paper was passed through meshing, finned heated rollers spaced a constant distance from 1 mm between the roll surfaces to produce a corrugated paper with good strength and flexibility to manufacture.

4 098ÖB / 1O06

Be is pie 1

4-0 parts of zirconium oxide fiber with a diameter of 0.5 to 4 / U were dispersed in 10,000 parts of water in a laboratory beater. 8 parts of an acrylic latex ("Revertex" Ä272) (pesticide content $ 0.50) and 8 parts of a zirconium oxide oil (as a 10 # dispersion) were added to this dispersion. Then a 10 # w / w solution of alum was added to bring the pH to 4.5. Then a paper was made on a laboratory screen former. The paper was dried at 100.degree. It "had a tensile strength of 10.5 kg / cm and a density of 0.25 g / cm 2. After heating at 800 ° C. for 2 hours, the tensile strength was 6.44 kg / cm ² .

Eg 1 10

100 parts of alumina fibers were dispersed in 20,000 parts of water in a laboratory beater. 20 parts of an acrylic latex ("Revertex" A2727) were added to this dispersion, whereupon 10 parts of an aluminum oxide sol (as AIoO _x ) as a 3.0% (w / w) dispersion in water were added, the sol used being composed of " Gerasol "existed. A TO 5% (w / w) alum solution was then added to bring the pH to 4.5.

This batch was drained on a cylindrical screen former with suction applied to one end to produce a bonded fiber structure which was closed at one end. After drying at 100 ⁰ O and after firing at TOOO ⁰ O, the product was strong and elastic and possessed excellent resistance to thermal shock.

EXAMPLE 1 11

150 parts of zirconia fibers were dispersed in 10,000 parts of water using a laboratory beater. 600 parts of a 30 # was added to this dispersion (W / w) silicon oxide sol dispersion, "lialcoag" NI030, and 250 parts of an acrylic latex "Revertex" A272 are added. The dispersion was further diluted by adding 90,000 parts of water and the pH was adjusted by adding a 10 # solution (W / w) alum solution brought to 4.5.

The dispersion was poured into a 5 cm radius cylindrical mold which had 825 uniformly arranged coaxial steel pins 1.6 mm in diameter and placed at 2.38 mm centers. One end of the "cylindrical form was perforated, and suction was applied to this end in order to mechanically remove as much water as possible from the dispersion. The solid" green "structure produced was ^{dried at 100 °} C., removed from the form and removed Fired at 1000 ^° C. for 2 hours.

Firing became a dry fiber matrix of 10 cm Diameter and 5 cm depth, the 825 parallel Had holes and had a density of approximately 0.6 kg / cnr.

Example 12

40 parts of zirconia fibers ("Zircar" ex Union Carbide Corporation) with an average diameter of 12 / U were placed in 20,000 parts of water in a laboratory beater dispersed in the usual way. About this dispersion 8! plots of a fiber-forming colloidal boehmite in In the form of a 5 3 igen {w / w} dispersion in water added

ben. Then a 10 # (w / w) solution of alum added to bring the pH to 4.

The mass was then drained on a cylindrical screen to make a bonded fiber ferrule. After drying and firing at 80O ⁰ C, a strong elastic product was obtained.

PATENT CLAIMS; 409886/1006

Claims (31)

PATENT CLAIMS: 1. mushroom product, characterized in that it
contains synthetic polycrystalline fibers and an inorganic binder. 2. Product according to claim 1, characterized in that. the fibers consist of metal oxide fibers. 3. Product according to claim 2, characterized in that
that the fibers consist of refractory fibers. 4. Product according to claim 3, characterized in that the strands consist of aluminum oxide fibers and / or zirconium oxide fibers. 5. Product according to claim 4, characterized in that the strands have been made by processing a composition into strands, the one Has a viscosity of more than 1 poise and is obtained from an aqueous solution or an aqueous sol of an oxychloride, basic acetate, basic formate or nitrate of aluminum and / or zirconium and contains a minor amount of a water-soluble organic polymer, the fibers so produced are dried and for the formation of the metal oxide and for decomposition of the polymer are heated. 6. Product according to claim 5 »characterized in that the conversion into fibers by extruding the composite 409886/1006 mensetzuhg through one or more holes in at least a gas flow has been effected, the one component higher speed in the direction of the extruded Composition,. '. 7. Product according to any one of the preceding claims, characterized in that the fiber rows are cut through Diameter of Ö, 'f> to 5, ÖyU have ^ 8. Product according to claim 7, characterized in that at least 90 # of the fibers eihen iJurchmesser ^r ranges from 2 to have AM; " 9 · Product according to one of the preceding claims, characterized characterized in that the fibers are largely shot-free are. 10. Product according to one of the preceding claims, daV characterized in that the inorganic binder consists of. Silicon oxide, zirconium oxide and aluminum oxide is selected. 11. Product according to claim ^10: characterized gekennizeichnet that the organic binder is selected from; a fibrous or fiber-forming boehmite tape. 12. Product according to one of the preceding claims, thereby characterized in that the proportion of polycrystalline Fibers 5 to 99 parts by weight per to 10 parts by weight of the dry product. 13. Product according to claim 12, characterized in that the proportion of polycrystalline fibers is 10 to 80 parts by weight per 100 parts by weight of the dry product '» 14. Product according to one of the preceding claims, characterized in that the proportion of inorganic Binder 1 to 95 parts by weight per 100 parts by weight of the dry product. 15. Product according to claim. 14, characterized in that the proportion of inorganic binder .10 .. to 50 parts by weight per 100 parts by weight of dry product. 16. Process for the production of inorganic fiIf products according to one of the preceding claims, characterized in that an aqueous dispersion, the synthetic polycrystalline inorganic fibers uiid contains a colloidal inorganic binder, and then the water from the dispersion removed from the felt product. 17. The method according to claim 16, characterized in that that the inorganic fibers in the dispersion have a Have a length of at least 0.5 mm. 18. The method according to claim 17, characterized in, that the inorganic fibers have a length of 0.5 to 25 mm "exhibit. 19. The method according to any one of claims 16 to 18, characterized in that a colloidal binder hydrated aluminum oxide, silicon oxide or Zirconium oxide or a mixture of two or more the same is used. 20. The method according to claim 19, characterized in that a fiber-forming or fibrous boehmite sol is used as the colloidal binder. 21. The method according to any one of claims 16 to 20, characterized 403886/10 06 - OBiGiNALINSPECTED characterized in that a water-soluble material which can be converted into a colloid is added to the dispersion and that the inorganic binder is formed by hydrolysis and / or heating. 22. The method according to any one of claims 16 to 21, characterized characterized in that the concentration of the inorganic binder is 0.002 to 2 parts by weight per 100 parts by weight the dispersion is. 23. The method according to any one of claims 16 to 22, characterized in that the concentration of the inorganic Fibers in the dispersion is 0.05 to 2 parts by weight per 100 parts by weight of the dispersion. 24. The method according to any one of claims 16 to 23, characterized in that an organic binder is present in the aqueous fiber dispersion. 25. The method according to any one of claims 16 to 24, characterized characterized in that the colloidal inorganic binder prior to removing the water from the dispersion is precipitated or coagulated. 26. The method according to any one of claims 16 to 25, characterized in that a retention aid in the Dispersion of the inorganic fibers is present. 27. The method according to claim 26, characterized in that
that the retention aid is a high molecular weight
Is polyamide. 28. The method according to any one of claims 16 to 27, characterized in that the water from the dispersion
removed by mechanical drainage. 409886/1006 29 «The method according to claim 28, characterized in that the product of the mechanical dewatering before the further drying is squeezed out. 30. The method according to claim 28 or 29, characterized in that that the product of the mechanical dehydration is dried by heating. 31. The method according to claim 30, characterized in that that the product of mechanical dewatering is then fired at a temperature of at least 500 ⁰ C. .KfINCKK DIPL-tNG. H. "O" MtUNQ. ·. STAK * 4098 86/1006