Process for producing porous materials
The present invention relates to a process for preparing a porous material, at least 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 (C) selected from the group consisting of alkali metal and earth alkali metal salts of a saturated or unsaturated monocarboxylic acid with 4 to 8 carbon atoms. 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, in particular in interior or exterior thermal insulation systems.
1. A process for preparing a porous material, the process comprising:
a) providing a mixture (I) comprising
(i) composition (A) comprising a catalyst (C) and 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 catalyst (C) is selected from the group consisting of an alkali metal linear saturated monocarboxylic acid with 4 to 7 carbon atoms, an earth alkali metal salt of linear saturated monocarboxylic acid with 4 to 7 carbon atoms, an alkali metal linear unsaturated monocarboxylic acid with 4 to 7 carbon atoms, an alkali metal salt of a linear unsaturated monocarboxylic acid with 4 to 7 carbon atoms, and a combination thereof.
2. The process according to claim 1 , wherein the catalyst (C) is selected from the group consisting of an alkali metal salt of a linear unsaturated monocarboxylic acid with 4 to 7 carbon atoms and an earth alkali metal salt of a linear unsaturated monocarboxylic acid with 4 to 7 carbon atoms.
3. The process according to claim 1 , wherein the catalyst (C) is selected from the group consisting of an alkali metal sorbate and an earth alkali metal sorbate.
4. The process according to claim 1 , wherein the catalyst (C) is present in the composition (A) in an amount of from 0.1 to 30% by weight, based on a total weight of the composition (A).
5. The process according to claim 1 , wherein the composition (A) comprises a glycol.
6. The process according to claim 5 , wherein the composition (A) comprises a glycol selected from the group consisting of monoethylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TrEG), tetraethylene glycol (TeEG), pentaethylene glycol (PeEG), hexaethylene glycol (HeEG), octaethylene glycol (OcEG), monopropylene glycol (MPG), dipropylene glycol (DPG), tripropylene glycol (TrPG), tetrapropylene glycol (TePG), pentapropylene (PePG), hexapropylene glycol (HePG), and octapropylene glycol (OcPG).
7. The process according claim 5 , wherein the catalyst (C) is mixed with the glycol to give a composition (C*).
8. The process according to claim 1 , wherein the composition (A) comprises at least one monool (am).
9. The process according to claim 1 , wherein the composition (A) comprises at least one polyfunctional isocyanate as component (a1).
10. The process according to claim 1 , wherein the composition (A) comprises at least one polyfunctional isocyanate as component (a1), at least one aromatic amine as component (a2), optionally water as component (a3), and optionally at least one further catalyst as component (a4).
11. The process according to claim 10 , wherein the at least one aromatic amine is a polyfunctional aromatic amine.
12. The process according to claim 10 , wherein the at least one aromatic amine (a2) is represented by formula I:
where
R 1 and R 2 are each independently selected from the group consisting of hydrogen and a linear or branched alkyl group comprising from 1 to 6 carbon atoms and Q 1 to Q 5 and Q 1′ to Q 5′ are each independently selected from the group consisting of hydrogen, a primary amino group, and a linear or branched alkyl group comprising from 1 to 12 carbon atoms, where the alkyl group optionally comprises a functional group, with the proviso that the at least one aromatic amine represented by the formula I comprises at least two primary amino groups, where at least one of Q 1 , Q 3 and Q 5 is a primary amino group and at least one of Q 1′ , Q 3′ and Q 5′ is a primary amino group.
13. The process according to claim 11 , wherein the composition (A) comprises
(a0) from 0.1 to 30% by weight of the catalyst (C),
(a1) from 25 to 94.9% by weight of the at least one polyfunctional isocyanate, and
(a2) from 0.1 to 30% by weight of the at least one polyfunctional aromatic amine,
which is represented by formula I;
where R 1 and R 2 are each independently selected from the group consisting of hydrogen and a linear or branched alkyl group comprising from 1 to 6 carbon atoms and Q 1 to Q 5 and Q 1′ to Q 5′ are each independently selected from the group consisting of hydrogen, a primary amino group, and a linear or branched alkyl group comprising from 1 to 12 carbon atoms, where the alkyl group optionally comprises a functional group, with the proviso that the at least one polyfunctional aromatic amine represented by the formula I comprises at least two primary amino groups, where at least one of Q 1 , Q 3 and Q 5 is a primary amino group and at least one of Q 1′ , Q 3′ and Q 5′ is a primary amino group,
(a3) from 0 to 15% by weight of water, and
(a4) from 0 to 29.9% by weight of the at least one further catalyst,
based on a total weight of the components (a0) to (a4), where the % by weight of the components (a0) to (a4) adds up to 100% by weight, and
wherein a sum of the components (a0) and (a4) is in the range of from 0.1 to 30% by weight based on the total weight of the components (a0) to (a4).
14. The process according to claim 10 , wherein the at least one aromatic amine component (a2) comprises at least one compound selected from the group consisting of 3,3,′,5,5′-tetraalkyl-4,4′-diaminodiphenylmethane, 3,3′,5,5′-tetraalkyl-2,2′-diaminodiphenylmethane and 3,3′,5,5′-tetraalkyl-2,4′-diaminodiphenylmethane, where the alkyl groups in the 3,3′,5 and 5′ positions are independently a linear or branched alkyl group comprising from 1 to 12 carbon atoms and optionally a functional group.
15. The process according to claim 10 , wherein the composition (A) comprises the at least one further catalyst, (a4), which catalyzes trimerization to form at least one isocyanurate group.
16. The process according to claim 10 , wherein the composition (A) comprises the at least one further catalyst (a4), which comprises at least one tertiary amino group.
17. The process according to claim 1 , wherein no water is used.
18. The process according to claim 1 , 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 a critical temperature and a critical pressure of the liquid comprised in the gel.
19. The process according to claim 1 , wherein the drying c) is carried out under supercritical conditions.
20. A porous material, obtained or obtainable by the process according to claim 1 .
21. A method of making a thermal insulation material or a vacuum insulation panel, the method comprising
preparing the thermal insulation material or the vacuum insulation panel with the porous materials according to claim 20 .
22. The method according to claim 21 , wherein the porous material is used in interior or exterior thermal insulation systems.