EP0000580B1 - Process for the preparation of inorganic-organic plastics - Google Patents

Description

Inorganic-organic plastics based on polyisocyanates and aqueous alkali silicate solutions are known; see e.g. DT-OS 1 770 384, 2 227 147, 2 359 606, 2 359 607, 2 359 608, 2 359 609, 2 359 610, 2 359 611, 2 359 612, DT-AS 2 325 090 and 2310559.

In this way, plastics can be produced which, due to the inorganic components, have above all improved fire resistance compared to purely organic substances and which, depending on the composition and reaction conditions, can be foamed or non-foamed, hard or soft, brittle or flexible. Due to the great variability of the properties, these inorganic-organic plastics offer a wide range of possible applications.

These combination plastics have in common that the organic and the inorganic phase must be mixed with one another for their production. This creates dispersions of type W / 0 (water in oil) or O / W (oil-in-water).

The plastics resulting from a W / O type dispersion are particularly interesting. They have high mechanical strengths, even when exposed to moisture, because the hardened, coherent organic phase envelops and thus fixes the likewise hardened aqueous, inorganic, incoherent phase. The perfect coherent organic phase of these plastics also depends on the improved fire resistance of such systems due to the amount of water enclosed.

Attempts have been made to produce the described plastics by mixing the reaction components in a batch or continuous mixer in one stage or in several stages and then allowing the resulting dispersion to solidify.

• a) einem organischen Polyisocyanat
• b) einer wäßrigen Silikatlösung
• c) einer organischen Komponente

so vorgenommen, daß zunächst die Anteile b) und c) vorgemischt oder aber a), b) und c) gleichzeitig vermischt werden.For example, according to DT-OS 2 359 606 the mixing of

• a) an organic polyisocyanate
• b) an aqueous silicate solution
• c) an organic component

in such a way that portions b) and c) are premixed or a), b) and c) are mixed simultaneously.

In this way, however, products are often obtained which, with an increasing proportion of organic component, can increasingly have faults which, in extreme cases, prevent the controlled build-up of an inorganic-organic plastic.

The invention is based, to avoid the disadvantages described above and to produce inorganic-organic plastics, even with high amounts of organic components, the task.

This object is achieved with the method according to the invention.

• a) einem organischen Polyisocyanat
• b) einer wäßrigen basischen Lösung und/oder einer wäßrigen basischen Suspension mit Gehalten an anorganischem Feststoff von 20-80 Gew.-%, vorzugsweise 30-70 Gew.-96,
• c) einer organischen Verbindung, die mindestens ein gegenüber Isocyanat reaktionsfähiges Wasserstoffatom sowie mindestens eine nichtionisch-hydrophile Gruppe enthält, und
• d) gegebenenfalls Katalysatoren und weiteren Zusatzmitteln und Ausreagierenlassen des so erhaltenen Gemischs,

dadurch gekennzeichnet, daß die Vermischung in der Weise vorgenommen wird, daß zunächst die Komponenten a) und b), gegebenenfalls unter Zusatz der ganzen Menge oder eines Teils der Komponente d), zu einer stabilen Primärdispersion umgesetzt und anschließend die Komponente c), gegebenenfalls unter Zusatz der ganzen Menge oder eines Teils der Komponente d), unter Ausbildung einer Enddispersion zugegeben wird, wobei die Enddispersion vor Beginn des Aushärtens bei Raumtemperatur einen Viskositätsbereich von 100-4000 cP aufweist und aus 10-50 Gew.-% anorganisch wäßriger Phase und 90-50 Gew.-% organischer Phase besteht.The present invention thus relates to a process for the preparation of inorganic-organic plastics of high strength, elasticity, heat resistance and flame resistance, consisting of a polymer-polysilicic acid gel composite material present as a colloidal xerosol by mixing

• a) an organic polyisocyanate
• b) an aqueous basic solution and / or an aqueous basic suspension with an inorganic solid content of 20-80% by weight, preferably 30-70% by weight,
• c) an organic compound which contains at least one hydrogen atom which is reactive toward isocyanate and at least one nonionic-hydrophilic group, and
• d) optionally catalysts and other additives and allowing the mixture thus obtained to react,

characterized in that the mixing is carried out in such a way that components a) and b), if appropriate with the addition of all or part of component d), are first converted into a stable primary dispersion and then component c), if appropriate under Addition of all or part of component d) is added, with the formation of a final dispersion, the final dispersion having a viscosity range of 100-4000 cP before the start of curing at room temperature and consisting of 10-50% by weight of inorganic aqueous phase and 90 -50 wt .-% organic phase.

The process according to the invention can be carried out continuously or preferably batchwise. After the discontinuous procedure, the stable primary dispersion is first prepared from polyisocyanate, aqueous basic solution or suspension and, if appropriate, further additives, such as activators, emulsifiers and blowing agents, and then the organic compound (component c)) is added. According to the continuous mode of operation, the primary dispersion is generated beforehand in a prechamber in accordance with the discontinuous mode of operation by means of a special mechanical arrangement; the mixing with the organic compound (component c)) takes place continuously in a downstream mixing head.

The discontinuous variant is recommended when using such organic compounds as component c) which, for example, spontaneously gel aqueous alkali silicate solutions. Here will preferably first a stable primary dispersion is prepared from polyisocyanate and, for example, aqueous alkali silicate, and component c) is then metered in.

Often desired, longer mixing times can be achieved by the discontinuous process in that the activator required for curing is only added after the stable primary dispersion has been prepared.

Organic compounds according to component c) which do not gel or only very slowly gel aqueous alkali silicates can be used either by the continuous or by the batch process.

According to the invention, mixing of the individual components, e.g. carried out in the order that first a spatially and temporally from components a) and b), optionally with the addition of all or part of component d), a dispersion is produced with the aid of a mixing unit and to this dispersion in a spatially and temporally then arranged mixing unit, component c), optionally with the addition of all or part of component d), is added.

• 1) Es werden zwei Rührwerksmischköpfe benutzt.
• 2) Es werden zwei Mischaggregate benutzt, die aus zwei nacheinander auf einer angetriebenen Achse angebrachten Mischorganen bestehen, wobei die Komponenten a) und b) [und ggf. d)] am oberen Teil der angetriebenen Achse eindosiert werden, die Komponente c) [und ggf. d)] dagegen im unteren Teil der Achse.
• 3) Die Mischaggregate bestehen aus zwei nacheinander angeordneten statischen Mischvorrichtungen, wobei die Komponenten a) und b) [und ggf. d)] am ersten statischen Mischer eindosiert werden und nach dem Passieren der ersten Mischstrecke im zweiten statischen Mischer mit der Komponente c) [und ggf. d)] vermischt werden.
• 4) Als erstes Mischaggregat wird ein Rührwerksmischkopf benutzt und als zweites Mischaggregat ein statischer Mischer.
• 5) Als erstes Mischaggregat wird ein statischer Mischer und als zweites Mischaggregat ein Rührwerksmischkopf benutzt.

There are various possibilities for the technical implementation of this successive mixing:

• 1) Two agitator mixing heads are used.
• 2) Two mixing units are used, which consist of two mixing elements mounted one after the other on a driven axle, components a) and b) [and possibly d)] being metered in at the upper part of the driven axle, components c) [and if necessary d)] on the other hand in the lower part of the axis.
• 3) The mixing units consist of two static mixing devices arranged one after the other, components a) and b) [and possibly d)] being metered in at the first static mixer and after passing through the first mixing section in the second static mixer with component c) [ and possibly d)] are mixed.
• 4) An agitator mixing head is used as the first mixing unit and a static mixer as the second mixing unit.
• 5) A static mixer is used as the first mixing unit and an agitator mixing head as the second mixing unit.

Starting components (component a) to be used according to the invention are aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, as described, for example, by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, for example those such as in DE-OS 2,647,482 pages 5-6 _- are called.

It is also possible to use the distillation residues containing isocyanate groups obtained in the technical production of isocyanates, optionally dissolved in one or more of the aforementioned polyisocyanates. It is also possible to use any mixtures of the aforementioned polyisocyanates.

The technically easily accessible polyisocyanates, e.g. 2,4- and 2,6-tolylene diisocyanate as well as any mixtures of these isomers ("TDI"), polyphenyl-polymethylene polyisocyanates, such as those produced by aniline-formaldehyde condensation and subsequent phosgenation ("crude MDI") and carbodiimide groups, Polyisocyanates containing urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups ("modified polyisocyanates").

Polyisocyanates containing ionic groups, as described in DT-OS 2 227 147, are particularly preferred according to the invention, for example sulfonated polyisocyanates (DT-OS 2227111, 2359614, 2 359 615), polyisocyanates containing carboxylate groups (DT-OS 2 359 613). Also preferred according to the invention are nonionic-hydrophilic polyisocyanates as described in DT-OS 2 325 909, furthermore polyisocyanates containing polar groups according to DT-OS 2 359 608 and phenolic OH groups containing polyisocyanates as described in DT OS 2 359 616.

The above-mentioned, particularly preferred polyisocyanates are preferably made from polyphenyl-polymethylene polyisocyanates, such as those produced by aniline-formaldehyde condensation and subsequent phosgenation ('crude MDI'), and from the distillation residues obtainable therefrom by distillation of two-core products, which generally have a viscosity between 50 and 50000 P / 25 ° C, an NCO content of 28-33 weight percent and a functionality> 2.

According to the invention, basic components (component b)) are furthermore aqueous basic solutions or suspensions with an inorganic solid content of 20-80% by weight, preferably 30-70% by weight, especially aqueous alkali silicate solutions or alkaline stabilized silica sols, but also liquid-flowable basic suspensions of finely divided fillers. The aforementioned aqueous basic solutions or suspensions are often also used in combination.

Aqueous solutions of alkali silicates are to be understood as the solutions of sodium and / or potassium silicate in water which are usually referred to as “water glasses”. It can too raw technical solutions, which can additionally contain, for example, calcium silicate, magnesium silicate, borates and aluminates, are used. Preferably, however, 32-54% by weight sodium silicate solutions are used, with a Na ₂ O / SiO ₂ molar ratio of 1: 1.6 to 1: 3.3.

Component c) is to be understood as meaning (preferably liquid at room temperature) organic compounds which, in addition to at least one isocyanate-reactive hydrogen atom, have at least one nonionic-hydrophilic group.

The nonionic-hydrophilic groups are primarily hydrophilic polyether groups.

Polyether groups which are composed of ethylene oxide and / or propylene oxide are preferred.

Suitable organic compounds which, in addition to a hydrogen atom which is reactive toward isocyanate, have at least one nonionic-hydrophilic group are, in particular, polyethers which are made up of alcohols with a functionality of 1-3 and ethylene oxide and / or propylene oxide and have terminal OH groups.

The hydrophilic center can also be introduced into the organic compound by incorporating a glycol such as tri- and tetraethylene glycol.

Of course, according to the invention, organic compounds having differently prepared polyether groups can also be used, provided that they contain - in addition to at least one reactive H atom - hydrophilic groups, e.g. monofunctional polyether based on monoalcohols and ethylene oxide. The proportion of ethylene oxide in the polyether should preferably be at least 10% by weight.

Nonionic-hydrophilic compounds suitable according to the invention are furthermore polycarbonates based on ethylene glycol, propylene glycol, tetraethylene glycol. Formose can also be used here, as it is e.g. in DT-OS 2,639,084, 2,639,083, 2,714,084, 2,714,104, 2,721,186 and 2,721,093.

Furthermore, compounds are also suitable which have a hydrophilic polyester segment, e.g. Contain triethylene glycol or diethylene glycol and succinic acid or oxalic acid. Such segments can be destroyed in the course of the further reaction with water glass, the organic component becoming hydrophobic with hardening of the inorganic component.

Polyethers which are composed of amines with a functionality of 1-4 and ethylene oxide and / or propylene oxide and have terminal OH groups are also particularly suitable for the batch process.

According to the invention, volatile organic substances are optionally used as blowing agents, such as those e.g. in DE-OS 2 647 482, page 13. A blowing effect can also be achieved by adding compounds which decompose at temperatures above room temperature with the elimination of gases, for example nitrogen, e.g. Azo compounds such as azoisobutyronitrile can be achieved.

The water contained in the aqueous basic solution or suspension can also take on the function of the blowing agent. Fine metal powders, e.g. Calcium, magnesium, aluminum or zinc serve as a blowing agent through the development of hydrogen with sufficient alkaline water glass, while at the same time exerting a hardening and strengthening effect.

According to the invention, catalysts are also often used, e.g. those as described in DE-OS 2 647 482 pages 13-15.

Further representatives of catalysts to be used according to the invention and details of the mode of action of the catalysts are in the plastics manual, volume VII, published by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich, 1966, e.g. on pages 96 to 102.

The catalysts are generally used in an amount between about 0.001 and 10% by weight, based on the amount of isocyanate.

According to the invention, surface-active additives (emulsifiers and foam stabilizers) can also be used, as well as reaction retarders, cell regulators of the type known per se, pigments, dyes, flame retardants, stabilizers against aging and weathering effects, plasticizers, fungistatic and bacteriostatic substances and fillers (cf. e.g. this DE-OS 2 647 482, pages 15-16).

Further examples of surface-active additives and foam stabilizers to be used according to the invention, as well as cell regulators, reaction retarders, stabilizers, anti-inflammatory substances, plasticizers, dyes and fillers, as well as fungistatic and bacteriostatic substances, and details on the use and action of these additives are given in the Plastics Manual, Volume VII by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, e.g. on pages 103 to 113. The mixing of the reaction components is preferably carried out at room temperature.

To interpret the technical advantages according to the invention, it is assumed that the primary dispersion produced in the meantime by the process according to the invention is extremely stable and that further additives do not endanger this stable state beyond the reaction and curing time.

According to the previous state of the art, on the other hand, dispersions are generally obtained which, with an increasing proportion of organic components and changing the W / O phase structure, undergo unstable dispersion states which, after hardening, can result in disturbances in the structure of the inorganic-organic plastic.

This is because organic substances, introduced using conventional mixing techniques, can initiate segregation processes and thereby prevent the production of technically useful inorganic-organic plastics. It is believed likely that such additives will gel the inorganic phase and / or that the organic and inorganic phase will not mix sufficiently due to the premature crosslinking reaction with the polyisocyanate.

The process products find the application known for organic-inorganic plastics, e.g. as sound and heat insulation materials, as building material, as concrete and joint sealing compounds.

Examples (Unless otherwise stated,% figures are percentages by weight). Starting materials: a) polyisocyanate component

A ₁ : Sufficient diisocyanatodiphenylmethane is distilled off from the crude phosgenation product of an aniline / formaldehyde condensate so that the distillation residue at 25 ° C. has a viscosity of 400 cP. (2-core fraction: 45.1% by weight, 3-core fraction :, 22.3% by weight, proportion of higher-core polyisocyanates: 32.6% by weight) NCO content: 30-31% by weight .

A ₂ : A ₁ sulfonated with gaseous sulfur trioxide (sulfur content: 0.96%, NCO content: 30.5%, viscosity at 25 ° C: 24000 cP, production see DT-OS 2 227 111).

A ₃ : Correspondingly A ₁ sulfonated with chlorosulfonic acid (sulfur content: 0.9%, NCO content: 30.2% viscosity at 20 ° C: 2000 cP).

b) silicate component

B ₁ : sodium water glass, 44% solids, molar weight ratio Na ₂ 0: Si0 ₂ = 1: 2

B ₂ : sodium water glass, 51% solids, molar weight ratio Na ₂ O: SiO ₂ = 1: 2

B ₃ : sodium water glass, 48.6% solid, molar weight ratio Na ₂ O: SiO ₂ = 1.2

c) polyether

C ₁ : Polyethylene oxide monoalcohol started on n-butanol OH number: 49.2

C ₂ : Polyethylene oxide-polypropylene oxide trial alcohol started on glycerin. OH number: 56

C ₃ : on sucrose / TMP / H20 / started polypropylene alcohol OH number: 380

C ₄ : Polypropylene tetra alcohol started on ethylenediamine. OH number: 630

C ₅ : 2.5 parts by weight of C ₁ + 7.5 parts by weight of C ₄

C ₆ : 5 parts by weight of C ₁ + 10 parts by weight of C ₄

d) Formose (manufactured according to DT-OS 2 721 186)

D ₁ : 14.5% H ₂ 0; Acid number 9.7; OH ― number 724

e) suspension

Production of a chalk suspension

E ₁ : 240 g of a chalk (specific weight: 2.7, 90% of the particles <2 μ, Omyalite 90 from Omya GmbH) were dissolved in 80 g of water and 5 g of a 30% aqueous solution of a high molecular weight di Potassium salt of a maleic acid-styrene copolymer with carboxylate and sulfonate groups suspended. Solids content: 75%.

example 1

Components II and III were premixed. Component I was 10 sec. mixed to achieve the primary dispersion with a high-speed stirrer, the mixture component (II + III) was then within 5 seconds. added with stirring. After 20 seconds Total mixing time was that Poured reaction mixture into a paper packet, started after 30 sec. to foam up and was after 85 sec. stiffens. A tough elastic inorganic-organic lightweight foam was obtained with a bulk density of 48 kg / m ³ and a compressive strength of 0.07 [MPa].

Comparative example

A conventional, simultaneous mixing of the three components according to Example 1 leads to a foam which is not practical, with foam disorders and defoamed, wet floor zone.

These segregation phenomena in the area of the soil zone are obviously caused by insufficient mixing of the individual components.

Example 2

Foaming was carried out according to Example 1. The foaming process continued after 28 seconds. on, after 75 sec. the reaction mixture had solidified.

Bulk density [kg / m ³ ]: 34

Compressive strength [MPa]: 0.06

• t_R = Rührzeit, Mischzeit der Mischung aus Komponente I, Komponente II und Komponente III
• t_L = Liegezeit, Zeitraum von Beginn des Mischens bis zum Beginn des Aufschäumens
• t_A = Abbindezeit, Zeitraum von Beginn des Mischens bis zur Erhärtung.

In the following examples mean:

• t _R = stirring time, mixing time of the mixture of component I, component II and component III
• t _L = lying time, period from the start of mixing to the start of foaming
• t _A = setting time, period from the start of mixing to hardening.

Example 3

• t_R: 20 sek., t_L: 33 sek., t_A: 85 sek.
• rohdichte [kg/m³]: 29
• Druckfestigkeit [MPa]: 0,04

Example 2 was repeated with an additional 3 g of polyether C ₃ in component II. A light foam was obtained with the following data:

• t _R : 20 sec., t _L : 33 sec., t _A : 85 sec.
• apparent density [kg / m ³ ]: 29
• Compressive strength [MPa]: 0.04

Example 4

• Rohdichte [kg/m³]: 42
• Druckfestigkeit [MPa]: 0,07

Foaming was carried out according to Example 1. A light foam was obtained with the data: t _R : 20 sec .; t _L : 40 sec .; t _A : 105 sec.

• Bulk density [kg / m ³ ]: 42
• Compressive strength [MPa]: 0.07

Example 5

• t_R: 20 sek.; t_L: 29 sek.; t_A: 105 sek,;
• Rohdichte [kg/m³]:, 50
• Druckfestigkeit [MPa]: 0,09

Foaming was carried out according to Example 1.

• t _R : 20 sec .; t _L : 29 sec .; t _A : 105 sec .;
• Gross density [kg / m ³ ] :, 50
• Compressive strength [MPa]: 0.09

Example 6

• t_R: 20 sek.; t_L: 42 sek.; t_A: 90 sek.;
• R ohdichte [kg/m³]: 61
• Druckfestigkeit [MPa]: 0.12

Foaming was carried out according to Example 1.

• t _R : 20 sec .; t _L : 42 sec .; t _A : 90 sec .;
• Tube density [kg / m ³ ]: 61
• Compressive strength [MPa]: 0.12

Example 7

• t_R: 20 sek.; t_L: 34 sek.; t_A: 140 sek.;

Foaming was carried out according to Example 1. A tough, elastic, inorganic-organic lightweight foam is obtained with the values:

• t _R : 20 sec .; t _L : 34 sec .; t _A : 140 sec .;

Conventional, simultaneous mixing of the 3 components leads to inhomogeneous, non-foamable reaction mixtures.

Further inorganic-organic foams produced according to Example 7 are listed in Table 1.

• TCAP: Tris(ß-chloräthyl)phosphat
• R₁₁: Trichlorfluormethan
• L 5340: Polyäthersiloxan der Fa. Union Carbide Corp.
• DB: Dimethylbenzylamin
  

It means:

• TCAP: Tris (ß-chloroethyl) phosphate
• R ₁₁ : trichlorofluoromethane
• L 5340: polyether siloxane from Union Carbide Corp.
• DB: Dimethylbenzylamine
  

Example 12

Components II and III were mixed. Component I was 10 sec. mixed to achieve the primary dispersion with a high-speed stirrer, the mixture component (II + III) was then within 5 seconds. added with stirring. After 20 seconds Total mixing time, the reaction mixture was poured into a paper packet, started after 37 seconds. to foam up and was frozen after 40 seconds. A tough, elastic, inorganic-organic lightweight foam with a bulk density of 48 kg / m ³ and a compressive strength of 0.09 [MPa] was obtained.

Further inorganic-organic foams produced according to Example 12 are listed in Table 2:

Example 18

Components II and III were premixed. Component I was 10 sec. mixed to achieve the primary dispersion with a high-speed stirrer, the mixture component (II + 111) was then within 5 seconds. added with stirring. After 20 seconds Total mixing time, the reaction mixture was poured into a paper packet, started after 34 seconds. lather and was, after 90 sec. stiffens. A tough-elastic inorganic-organic lightweight foam was obtained with a bulk density of 47 kg / m ³ and a compressive strength of 0.10 [MPa].
+) Unsaturated polyester resin from Bayer AG

Example 19

• t_R: 20, t_L: 30, t_A: 53
• Rohdichte [kg/m³]: 212
• Druckfestigkeit [MPa]: 0,60

Components I and II were 5 sec. mixed with a high-speed stirrer to achieve the primary dispersion. Component III was subsequently within 5 seconds. added with stirring. After 20 seconds Total mixing time, the reaction mixture was poured out into a paper packet. A hard foam was obtained with the values:

• t _R : 20, t _L : 30, t _A : 53
• Bulk density [kg / m ³ ]: 212
• Compressive strength [MPa]: 0.60

A conventional, simultaneous mixing of all three components leads within 20 seconds. to an inhomogeneous, highly viscous, non-foamable reaction mixture.

Example 20

According to Example 19, components I + II were premixed with a high-speed stirrer, component III was then within 5 seconds. added with stirring. After 30 seconds intensive mixing, the reaction mixture was poured into a wooden box mold of approx. 55 dm ³ , started after 48 sec. to foam up and was after 70 sec. stiffens. A hard inorganic-organic foam with a bulk density of 169 kg / m ³ and a compressive strength of 0.57 [MPa] was obtained.

Example 21

• t_R: 20 sek.; t_L: 30 sek.; t_A: 50 sek.
• Rohdichte [kg/m³]: 225
• Druckfestigkeite [MPa]: 0,58

Foaming was carried out according to Example 19.

• t _R : 20 sec .; t _L : 30 sec .; t _A : 50 sec.
• Bulk density [kg / m ³ ]: 225
• Compressive strength [MPa]: 0.58

Example 22

• t_R: 20 sek.; t_L: 29 sek.; t_A: 55 sek.
• Rohdichte [kg/m³]: 229
• Druckfestigkeit [MPa]: 0,42

Foaming was carried out according to Example 19.

• t _R : 20 sec .; t _L : 29 sec .; t _A : 55 sec.
• Bulk density [kg / m ³ ]: 229
• Compressive strength [MPa]: 0.42

Example 23

• t_R: 20 sek.; t_L: 31 sek.; t_A: 65 sek.;
• Rohdichte [kg/m³]: 166
• Druckfestigkeit [MPa]: 0,37

Foaming was carried out according to Example 19.

• t _R : 20 sec .; t _L : 31 sec .; t _A : 65 sec .;
• Bulk density [kg / m ³ ]: 166
• Compressive strength [MPa]: 0.37

Example 24

In a first stirrer, a dispersion of water glass (50% solids content) and polyisocyanate A is prepared, which is then mixed with a mixture M of the following composition in a second stirrer:

The product flows are set to the following values: water glass 8000 g / min, polyisocyanate 8040 g / min., 4920 g / min. the mixture M. Both mixing units have stirrers in an approx. 300 ml mixing chamber at 3000 rpm. The promotion takes place via standard gear pumps.

A uniformly fine-cell foam with a bulk density of 14 kg / m ^{3 is obtained} , which can be produced continuously without difficulty at heights of up to 80 cm and a width of 100 cm.

Example 25 (Comparative example)

With product flows of the same size as in Example 24, all components are simultaneously entered into a single mixing head. The foam that is now created is clearly heterogeneous and shows strong flow disturbances on the floor and on the sides, reaching up to a height of approx. 60% of the block height. The malfunctions cannot be eliminated by increasing the stirrer speed up to 6000 rpm; Likewise, adding more stabilizer does not bring any noticeable improvement, but instead leads to rapidly shrinking foams.

Example 26

With product streams of the same size as in Example 24, a dispersion of water glass and isocyanate is first produced in a mixing unit as in Example 24, which is fed to a static mixer and mixed with the mixture M there. An equally good foam is obtained as in Example 24.

Claims (6)

1. A process for the production of inorganic-organic synthetic materials having high strength, elasticity, dimensional stability under heat, and flame resistance, consisting of a polymer-polysilicic acid gel composite material in the form of a colloidal xerosol, by mixing

a) an organic polyisocyanate,

b) an aqueous alkali metal silicate solution, an alkali-stabilized silica sol, or a liquid-fluid basic suspension of finely-divided fillers, having an inorganic solid content of from 20 to 80% by weight,

c) an organic compound containing at least one isocyanate reactive hydrogen atom and at least one non-ionic-hydrophilic group and

d) optionally catalysts and other additives and leaving the resulting mixture to react, characterized in that mixing is carried out in that components a) and b), optionally with the addition of part or all of component d) are first reacted together to form a stable primary dispersion and thereafter component c), optionally with the addition of all or part of component d), is added to form the final dispersion, which final dispersion has a viscosity range of 100 to 4000 cP at room temperature before it begins to harden and consists of 10 to 50% by weight of inorganic aqueous phase and from 90 to 50% by weight of organic phase.

2. A process according to claim 1, characterized in that the alkali metal silicate used is sodium silicate having an Na₂O : SiO₂ molar ratio in the region of 1:1.6 to 1:3.3.

3. A process according to claims 1 to 2, characterized in that the organic polyisocyanates used are phosgenation products of aniline-formaldehyde condensation.

4. A process according to claims 1 to 3, characterized in that the polyisocyanate used is a polyisocyanate containing ionic groups.

5. A process according to claims 1 to 4, characterized in that the polyisocyanate containing ionic groups is a polyisocyanate containing sulphonic acid and/or sulphonate groups.

6. A process according to claims 1 to 2, characterized in that the polyisocyanate used is a prepolymer having isocyanate end groups and containing non-ionic-hydrophilic groups.