# US 2023/0265247 A1 · Process for preparing polyimides

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- Number: US 2023/0265247 A1
- Document ID: US20230265247A1
- Status: Published application
- Kind: A1
- Application number: 18/012,465
- Filed: 2021-06-17
- Published: 2023-08-24
- Earliest claimed: 2020-06-23
- Assignees: Technische UniversitäT Wien
- Applicants: Technische Universität Wien
- Inventors: Miriam Margarethe UNTERLASS; Daniel Alonso CERRON-INFANTES
- Web page: https://patentgrep.com/patent/US20230265247A1

## CPC

- C08G 73/1028: {characterised by the process itself, e.g. steps, continuous}
- C08G 73/1032: {characterised by the solvent(s) used}
- C08G 73/1082: {wholly aromatic in the tetracarboxylic moiety}
- C08G 73/1085: {Polyimides with diamino moieties or tetracarboxylic segments containing heterocyclic moieties}
- C09D 179/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08L 2203/16: used for films
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

The invention relates to a stoichiometric salt of a tetracarboxylic acid and a diamine of the following general formula (I), wherein R1 is selected from tetravalent residues of butane, cyclobutane, cyclopentane, cyclohexane, tetrahydrofurane and benzophenone and R2 is selected from divalent residues of unbranched, branched or cyclic aliphatic hydrocarbons with 3 to 15 carbon atoms, with the proviso that the salt of the formula (I) is water-soluble and is selected from compounds (1) to (28); and to the polyimides prepared from these salts by polycondensation.

## Claims

### Claim 1

A stoichiometric salt of a tetracarboxylic acid and a diamine of the following general formula (I):
wherein R1 is selected from tetravalent residues of butane, cyclobutane, cyclopentane, cyclohexane, tetrahydrofuran and benzophenone and R2 is selected from divalent residues of straight, branched or cyclic aliphatic hydrocarbons having from 3 to 15 carbon atoms,
wherein
i) the salt of formula (I) is water-soluble; and
ii) it is selected from the following compounds:
a) Salts of tetrahydrofuran-2,3,4,5-tetracarboxylic acid with aliphatic diamines
Propane-1,3 -diammonium-dihydrogen-tetrahydrofuran-2,3,4,5 -tetracarboxylate (1),
Butane-1,4-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (2),
Pentane-1,5-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (3),
2,2-Dimethylpropane-1,3-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (4),
Hexane-1,6-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5 -tetracarboxylate (5),
2-Methylpentane-1,5-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (6),
Heptane-1,7-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (7),
Octane-1,8-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (8),
Nonane-1,9-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (9);
b) Salts of tetrahydrofuran-2,3,4,5-tetracarboxylic acid with alicyclic diamines
Cyclohexane-1,2-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (10),
Cyclohexane-1,3 -diammonium-dihydrogen-tetrahydrofuran-2,3,4,5 -tetracarboxylate (11),
Cyclohexane-1,4-diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (12),
Cyclohexane-1,3-bis(methanammonium)-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (13),
Cyclohexane-1,4-bis(methanammonium)-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (14),
Norbornane bis(methylammonium)-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (15),
Isophorone diammonium-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (16),
Tricyclo[5.2.1.02,6]decane-3(4),8(9)-bis(methanammonium)-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (17),
4,4′-Methylene-bis(2-methylcyclohexylammonium)-dihydrogen-tetrahydrofuran-2,3,4,5-tetracarboxylate (18);
c) Salts of 1,2,3,4-butanetetracarboxylic acid with alicyclic diamines
Norbornane bis(methylammonium)-dihydrogen-1,2,3,4-butanetetracarboxylate (19),
Tricyclo[5.2.1.02,6]decane-3(4),8(9)-bis(methanammonium)-dihydrogen-1,2,3,4-butanetetracarboxylate (20);
d) Salts of 1,2,3,4-cyclobutanetetracarboxylic acid with alicyclic diamines
Norbornane bis(methylammonium)-dihydrogen-1,2,3,4-cyclobutanetetracarboxylate (21),
Tricyclo[5.2.1.02,6]decane-3(4),8(9)-bis(methanammonium)-dihydrogen-1,2,3,4-cyclobutanetetracarboxylate (22);
e) Salts of 1,2,3,4-cyclopentanetetracarboxylic acid with alicyclic diamines
Norbornane bis(methylammonium)-dihydrogen-1,2,3,4-cyclopentanetetracarboxylate (23),
Tricyclo[5.2.1.02,6]decane-3(4),8(9)-bis(methanammonium)-dihydrogen-1,2,3,4-cyclopentanetetracarboxylate (24);
f) Salts of 1,2,4,5-cyclohexanetetracarboxylic acid with alicyclic diamines
Norbornane bis(methylammonium)-dihydrogen-1,2,4,5-cyclohexanetetracarboxylate (25),
Tricyclo[5.2.1.02,6]decane-3(4),8(9)-bis(methanammonium)-dihydrogen-1,2,4,5-cyclohexane tetracarboxylate (26); and
g) Salts of 3,3′,4,4′-benzophenonetetracarboxylic acid with alicyclic diamines
Norbornane bis(methylammonium)-dihydrogen-3,3′,4,4′-benzophenone-tetracarboxylate (27),
Tricyclo[5.2.1.02,6]decane-3 (4), 8(9)-bis(methanammonium)-dihydrogen-3,3′,4,4′benzophenone tetracarboxylate (28).

### Claim 2 (depends on 1)

The salt of formula (I) according to claim 1, wherein the salt is selected from compounds (2), (3) and (5) to (9) above; or the salt is selected from the above compounds (10) to (28), wherein the residue R2 of the alicyclic diammonium ion is a mixture of multiple isomers in each case.

### Claim 3 (depends on 1)

A process for preparing the salt of formula (I) according to claim 1 by mixing the respective tetracarboxylic acid or dianhydride thereof with the respective diamine in a solvent and then isolating the stoichiometric salt thereby formed, wherein the tetracarboxylic acid or dianhydride thereof is dissolved, optionally under heating, in an organic solvent that is a solvent for both reactants but a non-solvent for the salt, followed by addition of the diamine and stirring of the reaction mixture to form the stoichiometric salt, which subsequently precipitates out of the solution and is isolated, wherein optionally
an aliphatic diamine having a chain length of 4 to 9 carbon atoms is added; or
an alicyclic diamine in the form of a mixture of multiple isomers is added.

### Claim 4 (depends on 3)

The process according to claim 3, wherein a protic polar solvent, preferably isopropanol, is used.

### Claim 5 (depends on 1)

A method of preparing polyimides comprising using the salt of formula (I) according to claim 1.

### Claim 6 (depends on 5)

The method according to claim 5, wherein a polyimide is prepared by subjecting an aqueous solution of the salt of formula (I) to a processing step and subsequent heating in order to bring about polycondensation and simultaneously evaporate the water.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the aqueous solution of the salt is formed into a desired shape or applied to a surface in the processing step prior to heating.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the aqueous solution of the salt is formed into a desired shape by foaming, with a foaming agent and/or a foam stabilizer being optionally added to the aqueous solution of the salt prior to foaming.

### Claim 9 (depends on 8)

The method according to claim 8, wherein at least one fatty acid dialkanolamide is added as a foam stabilizer.

### Claim 10

A polyimide of general formula (II) prepared using a salt of formula (I):
wherein R1 and R2 are as previously defined and n is ≥2, wherein the polyimide is selected from the following:
a) polyimides from tetrahydrofuran-2,3,4,5-tetracarboxylic acid and aliphatic diamines
poly(N,N′-(1,3-propylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (101),
poly(N,N′-(1,4-butylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (102),
poly(N,N′-(1,5-pentylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (103),
poly(N,N′-(2,2-dimethyl-1,3-propylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (104),
poly(N,N′-(1,6-hexylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (105),
poly(N,N′-(2-methyl-1,5-pentylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (106),
poly(N,N′-(1,7-heptylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (107),
poly(N,N′-(1,8-octylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (108),
poly(N,N′-(1,9-nonylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (109);
b) polyimides from tetrahydrofuran-2,3,4,5-tetracarboxylic acid and alicyclic diamines
poly(N,N′-(1,2-cyclohexylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (110),
poly(N,N′-(1,3-cyclohexylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (111),
poly(N,N′-(1,4-cyclohexylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (112),
poly(N,N′-(cyclohexane-1,3 -dimethylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (113),
poly(N,N′-(cyclohexane-1,4-dimethylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (114),
poly(N,N′-(norbornane dimethylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (115),
poly(N,N′-(isophorylene)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (116),
poly(N,N′-(tricyclo[5.2.1.02,6]decane-3(4), 8(9)-dimethylene)tetrahydrofuran-2,3,4,5 -tetracarboxylic acid diimide) (117),
poly(N,N′-(4,4′-methylene-bis(2-methylcyclohexyl)tetrahydrofuran-2,3,4,5-tetracarboxylic acid diimide) (118);
c) polyimides from 1,2,3,4-butanetetracarboxylic acid and alicyclic diamines
poly(N,N′-(norbornane dimethylene)butane-1,2,3,4-tetracarboxylic acid diimide) (119),
poly(N,N′-(tricyclo[5.2.1.02,6]decane-3(4),8(9)-dimethylene)butane-1,2,3,4-tetracarboxylic acid diimide) (120);
d) polyimides from 1,2,3,4-cyclobutanetetracarboxylic acid and alicyclic diamines
poly(N,N′-(norbornane dimethylene)cyclobutane-1,2,3,4-tetracarboxylic acid diimide) (121),
poly(N,N′-(tricyclo[5.2.1.02,6]decane-3(4),8(9)-dimethylene)cyclobutane-1,2,3,4-tetracarboxylic acid diimide) (122);
e) polyimides from 1,2,3,4-cyclopentanetetracarboxylic acid and alicyclic diamines
poly(N,N′-(norbornane dimethylene)cyclopentane-1,2,3,4-tetracarboxylic acid diimide) (123),
poly(N,N′-(tricyclo[5.2.1.02,6]decane-3(4),8(9)-dimethylene)cyclopentane-1,2,3,4-tetracarboxylic acid diimide) (124);
f) polyimides from 1,2,4,5-cyclohexanetetracarboxylic acid and alicyclic diamines
poly(N,N′-(norbornane dimethylene)cyclohexane-1,2,4,5-tetracarboxylic acid diimide) (125),
poly(N,N′-(tricyclo[5.2.1.02,6]decane-3(4),8(9)-dimethylene)cyclohexane-1,2,4,5-tetracarboxylic acid diimide) (126); and
g) polyimides from 3,3′,4,4′-benzophenonetetracarboxylic acid and alicyclic diamines
poly(N,N′-(norbornane dimethylene)-3,3′,4,4′-benzophenone tetracarboxylic acid diimide) (127),
poly(N,N′-(tricyclo[5.2.1.02,6]decane-3(4),8(9)-dimethylene)-3,3′,4,4′-benzophenonetetracarboxylic acid diimide) (128).