Inorganic foam based on calcium sulfoaluminate

Abstract

The present invention relates to a process for preparing a particle-stabilized inorganic foam based on calcium sulfoaluminate, to a particle-stabilized inorganic foam based on calcium sulfoaluminate, to a cellular material obtainable by hardening and optionally drying the particle-stabilized inorganic foam based on calcium sulfoaluminate, and to a composition for preparing an inorganic foam formulation for providing a particle-stabilized inorganic foam based on calcium sulfoaluminate.

Claims

1. A process for preparing an inorganic foam comprising the steps of (1) mixing (i) at least one group of inorganic particles; (ii) at least one amphiphilic compound; (iii) at least one inorganic binder mixture comprising (iiia) at least one calcium sulfoaluminate mixture, and optionally (iiib) at least one further inorganic binder selected from the group consisting of hydraulic binders, latent hydraulic binders, pozzolanic binders, and mixtures thereof; (iv) water; and optionally (v) at least one additive; and (2) foaming the resulting foam formulation by chemical, physical or mechanical foaming; wherein the at least one calcium sulfoaluminate mixture contains a) ye'elimite (4CaO×3Al.sub.2O.sub.3×SO.sub.3) and optionally belite (2CaO×SiO.sub.2) and b) anhydrite (CaSO.sub.4), calcium sulfate hemihydrate (CaSO.sub.4×0.5H.sub.2O) and/or gypsum (CaSO.sub.4×2H.sub.2O), in a weight ratio of a):b) of from 90:10 to 60:40.

2. The process according to claim 1, wherein the at least one group of inorganic particles is selected from the group consisting of oxides, hydroxides, carbides, nitrides, phosphates, carbonates, silicates, sulfates, and mixtures thereof.

3. The process according to claim 1, wherein the at least one group of inorganic particles is selected from the group consisting of silica particles, alumina particles, zirconia particles, CaCO.sub.3 particles, and mixtures thereof.

4. The process according to claim 1, wherein the at least one group of inorganic particles has a median particle size D.sub.50 in the range of from 30 nm to 300 μm.

5. The process according to claim 1, wherein the at least one amphiphilic compound comprises amphiphilic compounds with at least one polar head group and at least one apolar tail group, wherein the at least one head group is selected from the group consisting of phosphates, phophonates, sulfates, sulfonates, alcohols, amines, amides, pyrrolidines, gallates, and carboxylic acids; and wherein the at least one tail group is selected from an aliphatic or an aromatic or a cyclic group with 2 to 8 carbon atoms, wherein the carbon atoms are optionally substituted with one or more, same or different substituents selected from C.sub.1-C.sub.8-alkyl, secondary —OH, and secondary —NH.sub.2.

6. The process according to claim 1, wherein the at least one amphiphilic compound comprises amphiphilic compounds with at least one head group selected from the group consisting of carboxylic acids, gallates and amines, and at least one tail group selected from aliphatic groups with 2 to 8 carbon atoms.

7. The process according to claim 1, wherein the at least one calcium sulfoaluminate mixture has the analytical oxide composition of 5 to 35 wt.-% of SO.sub.3, 30 to 60 wt.-% of CaO, 0 to 30 wt.-% of SiO.sub.2 and 5 to 35 wt.-% of Al.sub.2O.sub.3.

8. The process according to claim 1, wherein the at least one further inorganic binder is selected from the group consisting of blast furnace slag, microsilica, metakaolin, aluminosilicates, fly ash, and mixtures thereof.

9. The process according to claim 1, wherein the at least one further inorganic binder is a mixture of metakaolin and fly ash.

10. The process according to claim 1, wherein the at least one inorganic binder mixture (iii) comprises (iiic) at least one cement selected from CEM I, CEM II, CEM III, CEM IV, CEM V cements, according to DIN EN 197-1 (11/2011), or calcium aluminate cement.

11. The process according to claim 1, wherein the at least one additive is selected from the group consisting of pH modifiers, fillers, accelerators, retarders, rheology modifiers, superplasticizers, surfactants, fibers, waterglass, further hydrophobization agents, catalysts, and mixtures thereof.

12. The process according to claim 1, wherein the amount of amphiphilic compound to inorganic particle surface is from 0.5 to 160 μmol/m2; and/or wherein the inorganic particles are provided in an amount of from 0.1 to 25 wt.-% with regard to the amount of the at least one inorganic binder mixture; and/or wherein the weight ratio of water to the inorganic binder mixture is from 0.1 to 2.0.

13. The process according to claim 1, wherein step (1) comprises the steps of (1a) dispersing the at least one group of inorganic particles, the at least one amphiphilic compound, and optionally the at least one additive in water to obtain an aqueous dispersion; and (1b) mixing the aqueous dispersion with the at least one inorganic binder mixture.

14. An inorganic foam obtained by the process according to claim 1.

15. A cellular material obtained by hardening and optionally drying an inorganic foam according to claim 14.

16. An inorganic foam comprising (i) at least one group of inorganic particles; (ii) at least one amphiphilic compound; (iii) at least one inorganic binder mixture comprising (iiia) at least one calcium sulfoaluminate mixture, and optionally (iiib) at least one further inorganic binder selected from the group consisting of hydraulic binders, latent hydraulic binders, pozzolanic binders, and mixtures thereof; (iv) water; and optionally (v) at least one additive; wherein the at least one calcium sulfoaluminate mixture contains a) ye'elimite (4CaO×3Al.sub.2O.sub.3×SO.sub.3) and optionally belite (2CaO×SiO.sub.2) and b) anhydrite (CaSO.sub.4), calcium sulfate hemihydrate (CaSO.sub.4×0.5H.sub.2O) and/or gypsum (CaSO.sub.4×2H.sub.2O), in a weight ratio of a):b) of from 90:10 to 60:40.

17. The process according to claim 1, wherein the at least one inorganic binder mixture (iii) comprises CEM I cement, according to DIN EN 197-1 (11/2011).

18. A cellular material obtained by hardening and optionally drying an inorganic foam according to claim 16.

19. A composition for preparing an inorganic foam formulation comprising as components (i) at least one group of inorganic particles; (ii) at least one amphiphilic compound; (iii) at least one inorganic binder mixture comprising (iiia) at least one calcium sulfoaluminate mixture, and optionally (iiib) at least one further inorganic binder selected from the group consisting of hydraulic binders, latent hydraulic binders, pozzolanic binders, and mixtures thereof; wherein the components (i), (ii), and (iii) are present separately; or the components (i) and (ii) are present as a mixture and the component (iii) is present separately; or the components (i), (ii) and (iii) are present as a mixture; wherein the at least one calcium sulfoaluminate mixture contains a) ye'elimite (4CaO×3Al.sub.2O.sub.3×SO.sub.3) and optionally belite (2CaO×SiO.sub.2) and b) anhydrite (CaSO.sub.4), calcium sulfate hemihydrate (CaSO.sub.4×0.5H.sub.2O) and/or gypsum (CaSO.sub.4×2H.sub.2O), in a weight ratio of a):b) of from 90:10 to 60:40.

20. A process for preparing an inorganic foam comprising the steps of (1) mixing (i) at least one group of inorganic particles; (ii) at least one amphiphilic compound; (iii) at least one inorganic binder mixture comprising (iiia) at least one calcium sulfoaluminate mixture, and optionally (iiib) at least one further inorganic binder selected from the group consisting of hydraulic binders, latent hydraulic binders, pozzolanic binders, and mixtures thereof; (iv) water; and optionally (v) at least one additive; and (2) foaming the resulting foam formulation by chemical, physical or mechanical foaming; wherein the at least one further inorganic binder is a mixture of metakaolin and fly ash.

21. A process for preparing an inorganic foam comprising the steps of (1) mixing (i) at least one group of inorganic particles; (ii) at least one amphiphilic compound; (iii) at least one inorganic binder mixture comprising (iiia) at least one calcium sulfoaluminate mixture, and optionally (iiib) at least one further inorganic binder selected from the group consisting of hydraulic binders, latent hydraulic binders, pozzolanic binders, and mixtures thereof; (iv) water; and optionally (v) at least one additive; and (2) foaming the resulting foam formulation by chemical, physical or mechanical foaming; wherein the at least one inorganic binder mixture (iii) comprises (iiic) at least one cement selected from CEM I, CEM II, CEM III, CEM IV, CEM V cements, according to DIN EN 197-1 (11/2011), or calcium aluminate cement.

22. A process for preparing an inorganic foam comprising the steps of (1) mixing (i) at least one group of inorganic particles; (ii) at least one amphiphilic compound; (iii) at least one inorganic binder mixture comprising (iiia) at least one calcium sulfoaluminate mixture, and optionally (iiib) at least one further inorganic binder selected from the group consisting of hydraulic binders, latent hydraulic binders, pozzolanic binders, and mixtures thereof; (iv) water; and optionally (v) at least one additive; and (2) foaming the resulting foam formulation by chemical, physical or mechanical foaming; wherein step (1) comprises the steps of (1a) dispersing the at least one group of inorganic particles, the at least one amphiphilic compound, and optionally the at least one additive in water to obtain an aqueous dispersion; and (1b) mixing the aqueous dispersion with the at least one inorganic binder mixture.

Description

EXAMPLES

Comparative Example 1

(1) A geopolymer foam was prepared from the following composition of raw materials in weight percent:

(2) 20.5% Metakaolin (Argical™ M 1200S, Imerys)

(3) 20.5% Fly ash (Microsit® M10, BauMineral) 7.8% Calcium aluminate cement (Ciment Fondu®, Kerneos)

(4) 1.2% Surfactant (Alkyl Polyglucoside, Glucopon®, 225 DK, BASF)

(5) 0.2% PAN Fibers (6 mm, 6.7 dtex)

(6) 19.5% Water

(7) 27.4% Waterglass (“Kaliwasserglass K58”, BASF)

(8) 2.9% NaOH

(9) The liquid raw materials were first mixed with NaOH. The solid raw materials were added to the liquid components and stirred until a homogeneous slurry is created. The foam was then generated with a kitchen mixer. The so obtained foam was poured to a mold. The setting reaction took place and the foam started to solidify. The geopolymer foam was stored in humid atmosphere for 3 days to allow proper setting. Thereafter, it was demolded and dried at 70° C. until constant mass.

(10) The resulting geopolymer foam part exhibited a dimension of 300 mm×300 mm×40 mm. Its dry density was 144 kg/m.sup.3 and its thermal conductivity 42.1mW/mK. The compressive strength was 48 kPa, the flexural strength was 28 kPa. The sample featured an air flow resistivity (DIN EN 29 053) of 4.2 kPa s/m.sup.2. The foam exhibited mainly open pores as shown in FIG. 1.

Comparative Example 2

(11) A mixture comprising 79.8 wt.-% calcium carbonate (Socal 31), 15.1 wt.-% butyl gallate and 5.1 wt.-% manganese (IV) oxide was premixed as “Foam Formation Powder”.

(12) A geopolymer foam was prepared from the following composition of raw materials in weight percent:

(13) 19.2% Metakaolin (Argical™ M 1200S, Imerys)

(14) 19.2% Fly ash (Microsit® M10, BauMineral)

(15) 7.3% Calcium aluminate cement (Ciment Fondu®, Kerneos)

(16) 2.3% Foam Formation Powder

(17) 0.2% PAN Fibers (6 mm, 6.7 dtex)

(18) 23.4% Water

(19) 26.3 Waterglass (“Kaliwasserglass K58”, BASF)

(20) 2.8% Hydrogen Peroxide (50% solution)

(21) The foam formation powder was first dispersed in water. Then, the suspension was added to the waterglass. The mix of metakaolin and fly ash was added and the suspension was stirred for 10 min. Subsequently, the calcium aluminate cement was admixed. After 15 min of stirring, the foaming of the suspension was initiated by adding the hydrogen peroxide. The so obtained slurry was poured to a mold where the foam expansion evolves until the decomposition of the hydrogen peroxide was completed. The prepared wet foam was stable until after about 30 min the setting reaction took place and the foam started to solidify. The geopolymer foam was stored in humid atmosphere for 3 days to allow proper setting. Thereafter, it was demolded and dried at 70° C. until constant mass.

(22) The resulting geopolymer foam part exhibited a dimension of 200 mm×200 mm×50 mm. Its dry density was 127 kg/m.sup.3 and its thermal conductivity 39.6 mW/mK. The sample featured an air flow resistivity of 233 kPa s/m.sup.2. The foam exhibited mainly closed pores. A picture of the foam is provided in FIG. 2.

Working Example 1

(23) A mixture comprising 88.5 wt.-% calcium carbonate (Schafer Precarb 100), 5.8 wt.-% enanthic acid and 5.7 wt.-% manganese (IV) oxide was premixed as “Foam Formation Powder”.

(24) A calcium sulfoaluminate foam was prepared from the following composition of raw materials in weight percent:

(25) 39.4% Calcium Sulfoaluminate (Alipre®, ltalcementi)

(26) 12.2% Calcium Sulfate Dihydrate

(27) 6.5 Foam Formation Powder

(28) 0.3 PAN Fibers (6 mm, 6.7 dtex)

(29) 38.7% Water

(30) 2.9% Hydrogen Peroxide (50% solution)

(31) The foam formation powder was first dispersed in water. Then, the mix of calcium sulfoaluminate and calcium sulfate dihydrate was admixed. After 15 min of stirring, the foaming of the suspension was initiated by adding the hydrogen peroxide. The so obtained slurry was poured to a mold where the foam expansion evolved until the decomposition of the hydrogen peroxide was completed. The prepared wet foam was stable until after about 15 min the setting reaction took place and the foam started to solidify. The calcium sulfoaluminate foam was stored in humid atmosphere over night to allow proper setting. Thereafter, it was demolded and dried at 70° C. until constant mass.

(32) The resulting calcium sulfoaluminate foam part exhibited a dimension of 240 mm×480 mm×100 mm. Its dry density was 111 kg/m.sup.3 and its thermal conductivity 42.1 mW/mK. The compressive strength was 48 kPa. The sample featured an air flow resistivity of 1990 kPa s/m.sup.2. The foam exhibited closed pores as shown in FIG. 3.

Working Example 2

(33) A mixture comprising 83.7 wt.-% calcium carbonate (Schafer Precarb 100), 5.5 wt.-% enanthic acid and 10.8 wt.-% manganese (IV) oxide was premixed as “Foam Formation Powder”.

(34) A calcium sulfoaluminate foam was prepared from the following composition of raw materials in weight percent:

(35) 18.7% Calcium Sulfoaluminate (Alipre®, ltalcementi)

(36) 5.8% Calcium Sulfate Dihydrate

(37) 12.2% Metakaolin (Argical™ M 1200S, lmerys)

(38) 12.2% Fly Ash (Microsit® M10, BauMineral)

(39) 3.7% Foam Formation Powder

(40) 0.2% PAN Fibers (6 mm, 6.7 dtex)

(41) 43.9% Water

(42) 3.2% Hydrogen Peroxide (50% solution)

(43) The foam formation powder was first dispersed in water. Then, the mix of calcium sulfoaluminate, calcium sulfate dihydrate, metakaolin and fly ash was admixed. After 15 min of stirring, the foaming of the suspension was initiated by adding the hydrogen peroxide. The so obtained slurry was poured to a mold where the foam expansion evolved until the decomposition of the hydrogen peroxide was completed. The prepared wet foam was stable until after about 15 min the setting reaction took place and the foam started to solidify. The calcium sulfoaluminate foam was stored in humid atmosphere for 3 days to allow proper setting. Thereafter, it was demolded and dried at 70° C. until constant mass.

(44) The resulting calcium sulfoaluminate foam part exhibited a dimension of 240 mm×480 mm×100 mm. Its dry density was 83 kg/m.sup.3 and its thermal conductivity 36.4mW/mK. The compressive strength was 43 kPa, the flexural strength was 28 kPa. The sample featured an air flow resistivity of 2220 kPa s/m.sup.2. The foam exhibited closed pores as shown in FIG. 4.