PROCESS FOR PRODUCING POROUS MATERIALS

Abstract

The present invention relates to a process for preparing a porous material, at least comprising the steps of providing a mixture (I) comprising a composition (A) comprising components suitable to form an organic gel and a solvent (B), reacting the components in the composition (A) in the presence of the solvent (B) to form a gel, and drying of the gel obtained in step b), wherein the composition (A) comprises a catalyst system (CS) at least comprising a catalyst component (C1) selected from the group consisting of ammonium salts and a carboxylic acid as catalyst component (C2). The invention further relates to the porous materials which can be obtained in this way and the use of the porous materials as thermal insulation material and in vacuum insulation panels and vacuum insulation systems, in particular in interior or exterior thermal insulation systems as well as for the insulation of refrigerators and freezers and in water tank or ice maker insulation systems.

Claims

1-16. (canceled)

17. A process for preparing a porous material, the process comprising: a) providing a mixture (I) comprising (i) a composition (A) comprising components suitable to form an organic gel and (ii) a solvent (B), b) reacting the components in the composition (A) in the presence of the solvent (B) to form a gel, and c) drying the gel obtained in b), wherein the composition (A) comprises a catalyst system (CS) comprising a tetraalkylammonium salt as a catalyst component (C1) and a carboxylic acid as a catalyst component (C2), and at least one polyfunctional isocyanate as component (al).

18. The process according to claim 17, wherein the catalyst system (CS) comprises a tetraalkylammonium hydroxide as the catalyst component (C1).

19. The process according to claim 18, wherein the tetraalkylammonium hydroxide is selected from the group consisting of tetramethylammonium hydroxide, tetra(n-butyl)ammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, hexa-decyltrimethylammonium hydroxide, tetrahexylammonium hydroxide, triethylmethylammonium hydroxide, tetraoctylammonium hydroxide, tri-n-butylmethylammonium hydroxide, diethyl dimethylammonium hydroxide, octyltrimethylammonium hydroxide, trimethylethylammonium hydroxide, tetrapentylammonium hydroxide, tripropylmethylammonium hydroxide, tetrakisdecylammonium hydroxide, and tributyl ethyl ammonium hydroxide.

20. The process according to claim 17, wherein the carboxylic acid is selected from the group consisting of an aliphatic or aromatic monocarboxylic acid with 1 to 24 carbon atoms, an aliphatic or aromatic dicarboxylic acid with 1 to 24 carbon atoms, an aliphatic or aromatic tricarboxylic acid with 1 to 24 carbon atom, and an aliphatic or aromatic tetracarboxylic acid with 1 to 24 carbon atoms.

21. The process according to claim 17, wherein the carboxylic acid is selected from the group consisting of a saturated or an unsaturated monocarboxylic acid with 1 to 24 carbon atoms, a saturated or an unsaturated dicarboxylic acid with 1 to 24 carbon atom, a saturated or an unsaturated tricarboxylic acid with 1 to 24 carbon atoms, and a saturated or an unsaturated tetracarboxylic acid with 1 to 24 carbon atoms.

22. The process according to claim 17, wherein the catalyst system (CS) is added in a form of an aqueous solution.

23. The process according to claim 17, wherein the composition (A) comprises at least one monool.

24. The process according to claim 17, wherein the composition (A) further comprises at least one aromatic amine as component (a2), optionally water as component (a3), and optionally at least one further catalyst as component (a4).

25. The process according to claim 17, wherein the drying c) is carried out by converting liquid comprised in the gel into a gaseous state at a temperature and a pressure below the critical temperature and the critical pressure of the liquid comprised in the gel.

26. The process according to claim 17, wherein the drying c) is carried out under supercritical conditions.

27. A porous material, obtained by the process according to claim 17.

28. A method for preparing a thermal insulation material or a vacuum insulation panel, the method comprising preparing the thermal insulation material or the vacuum insulation panel using the porous materials according to claim 27.

29. The method according to claim 28, wherein the porous material is used in an interior or exterior thermal insulation system.

30. The method according to claim 29, wherein the porous material is used for insulation of thermal bridges.

31. The method according to claim 29, wherein the porous material is used for insulation of refrigerators or freezers.

Description

EXAMPLES

1. Methods

1.1 Determination of Thermal Conductivity

[0317] The thermal conductivity was measured according to DIN EN 12667 with a heat flow meter from Hesto (Lambda Control A50).

1.2 Solvent Extraction with Supercritical Carbon Dioxide

[0318] One or several gel monoliths were placed onto sample trays in an autoclave of 25 I volume. Subsequent to filling with supercritical carbon dioxide (scCO.sub.2), the gelation solvent was removed (drying) by flowing scCO.sub.2 through the autoclave for 24 h (20 kg/h). Process pressure was kept between 120 and 130 bar and process temperature at 60° C. in order to maintain carbon dioxide in a supercritical state. At the end of the process, the pressure was reduced to normal atmospheric pressure in a controlled manner. The autoclave was opened, and the obtained porous monoliths were removed.

1.3 Determination of Compressive Strength and E Modulus

[0319] The compressive strength and the elastic modulus was measured according to DIN EN ISO 844with 10% strain.

2. Materials

[0320] Component a1: Oligomeric MDI (Lupranat M200) having an NCO content of 30.9 g per 100 g in accordance with ASTM D-5155-96 A, a functionality in the region of three and a viscosity of 2100 mPa.s at 25° C. in accordance with DIN 53018 (hereinafter “M200”) [0321] Component a2: 3,3′,5,5′-Tetraethyl-4,4′diaminodiphenylmethane (hereinafter “MDEA”) [0322] Component a3: Ethane-1,2-diol (hereinafter: “MEG”) [0323] Component a4: Exolit® OP560 (hereinafter: “OP560”) [0324] Component a5: n-Butanol [0325] Catalysts: Tetrabutylammonium hydroxide (55 wt % in water, hereinafter “TBA-OH”) [0326] Carboxylic acids: Acetic acid [0327] Citric acid [0328] 2-Ethylhexanoic acid [0329] (2E,4E)-Hexa-2,4-dienoic acid

3. Examples

[0330] Thermal conductivity values for all examples are shown in Table 1. Furthermore, data regarding the compressive strength and density are included for several examples.

3.1 Example 1 (Comparative)

[0331] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 0.93 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.30 g TBA-OH and 0.13 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was broken upon handling and subsequently not supercritically dried.

3.2 Example 2 (Comparative)

[0332] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 0.93 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.10 g 2-ethylhexanoic acid and 0.26 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was broken upon handling and subsequently not supercritically dried.

3.3 Example 3 (Comparative)

[0333] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 0.93 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.07 g (2E,4E)-hexa-2,4-dienoic acid and 0.26 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was broken upon handling and subsequently not supercritically dried.

3.4 Example 4 (Comparative)

[0334] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 1.00 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.05 g acetic acid and 0.24 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was broken upon handling and subsequently not supercritically dried.

3.5 Example 5

[0335] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 0.93 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.32 g TBA-OH, 0.10 g 2-ethylhexanoic acid and 0.12 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h.

[0336] The resulting monolithic gel slab was dried through solvent extraction with scCO.sub.2 in a 25 I autoclave leading to a porous material.

[0337] The compressive strength was determined according to DIN EN ISO 844 with 6% strain. The compressive strength was 0.461 N/mm.sup.2.

3.6 Example 6

[0338] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 0.93 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.30 g TBA-OH, 0.07 g (2E,4E)-hexa-2,4-dienoic acid and 0.13 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was dried through solvent extraction with scCO.sub.2 in a 25 I autoclave leading to a porous material.

[0339] The compressive strength was determined according to DIN EN ISO 844 with 6% strain. The compressive strength was 0.469 N/mm.sup.2.

3.7 Example 7

[0340] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 1.00 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.39 g TBA-OH, 0.05 g acetic acid and 0.06 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was dried through solvent extraction with scCO.sub.2 in a 25 I autoclave leading to a porous material.

[0341] The compressive strength was determined according to DIN EN ISO 844 with 6% strain. The compressive strength was 0.429 N/mm.sup.2.

3.8 Example 8 (Comparative)

[0342] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 1.00 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.13 g citric acid and 0.29 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was broken upon handling and subsequently not supercritically dried.

3.9 Example 9

[0343] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 1.00 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.32 g TBA-OH, 0.07 g citric acid and 0.07 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was dried through solvent extraction with scCO.sub.2 in a 25 I autoclave leading to a porous material.

[0344] The compressive strength was determined according to DIN EN ISO 866 with 6% strain. The compressive strength was 0.366 N/mm.sup.2.

3.10 Example 10

[0345] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 1.00 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.64 g TBA-OH, 0.13 g citric acid and 0.13 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was dried through solvent extraction with scCO.sub.2 in a 25 I autoclave leading to a porous material.

[0346] The compressive strength was determined according to DIN EN ISO 866 with 6% strain. The compressive strength was 0.309 N/mm.sup.2.

3.11 Example 11

[0347] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 1.00 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.32 g TBA-OH, 0.04 g citric acid and 0.04 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was dried through solvent extraction with scCO.sub.2 in a 25 I autoclave leading to a porous material.

[0348] The compressive strength was determined according to DIN EN ISO 866 with 6% strain. The compressive strength was 0.366 N/mm.sup.2.

3.12 Example 12

[0349] In a polypropylene container, 32.00 g M200 were stirred in 293.33 g MEK at 20° C. leading to a clear solution. Similarly, 5.33 g MDEA, 1.33 g MEG, 1.00 g OP560, 1.00 g water and 2.67 g butanol were dissolved in 293.33 g MEK before a previously prepared solution containing 0.96 g TBA-OH, 0.13 g citric acid and 0.13 g water was added. The solutions were combined in a rectangular container (16 cm×16 cm×3 cm height) by pouring one solution into the other, which led to a homogeneous mixture of low viscosity. The container was closed with a lid and the mixture was gelled at room temperature for 24 h. The resulting monolithic gel slab was dried through solvent extraction with scCO.sub.2 in a 25 I autoclave leading to a porous material.

[0350] The compressive strength was determined according to DIN EN ISO 866 with 6% strain. The compressive strength was 0.151 N/mm.sup.2.

4. Results

[0351]

TABLE-US-00001 TABLE 1 Results. Thermal conductivity Compressive Density [mW/m*K] (p = 1 bar, strength [kg/m.sup.3] T = 10° C.) [kPa] Example 1 (comparative) Not determined, gel instable 5.33 g MDEA, 0.30 g TBA-OH Example 2 (comparative) Not determined, gel instable 5.33 g MDEA, 0.10 g 2-ethylhexanoic acid Example 3 (comparative) Not determined, gel instable 5.33 g MDEA, 0.07 g (2E,4E)-hexa-2,4-dienoic acid Example 4 (comparative) Not determined, gel instable 5.33 g MDEA, 0.05 g acetic acid Example 5 121 17.1 461 5.33 g MDEA, 0.32 g TBA-OH + 0.10 g 2-ethylhexanoic acid Example 6 118 17.4 469 5.33 g MDEA, 0.30 g TBA-OH + 0.07 g (2E,4E)-hexa-2,4-dienoic acid Example 7 126 16.9 429 5.33 g MDEA, 0.39 g TBA-OH + 0.05 g acetic acid Example 8 (comparative) Not determined, gel instable 5.33 g MDEA, 0.13 g citric acid Example 9 114 16.5 366 5.33 g MDEA, 0.32 g TBA-OH + 0.07 g citric acid Example 10 130 16.3 309 5.33 g MDEA, 0.64 g TBA-OH + 0.13 g citric acid Example 11 111 16.7 366 5.33 g MDEA, 0.32 g TBA-OH + 0.04 g citric acid Example 12 177 16.6 151 5.33 g MDEA, 0.96 g TBA-OH + 0.13 g citric acid

5. Abbreviations

[0352] OP560 Exolit® OP560

[0353] H.sub.2O Water

[0354] M200 Lupranate M200 (polyisocyanate)

[0355] MEG Ethane-1,2-diol

[0356] MEK Methyl ethyl ketone

[0357] MDEA 4,4′-Methylene-bis(2,6-diethylaniline)

[0358] TBA-OH Tetrabutylammonium hydroxide (55 wt % in water)

Literature Cited

[0359] WO 95/02009 A1

[0360] WO 2008/138978 A1

[0361] WO 2011/069959 A1

[0362] WO 2012/000917 A1

[0363] WO 2012/059388 A1

[0364] WO 2016/150684 A1

[0365] PCT/EP2017/05094

[0366] PCT/EP2017/050948

[0367] WO 2009/027310 A1

[0368] Polyurethane, 3.sup.rd edition, G. Oertel, Hanser Verlag, Munich, 1993

[0369] Plastics Additive Handbook, 5th edition, H. Zweifel, ed. Hanser Publishers, Munich, 2001