Polyester carbonates from cycloaliphatic diacids and aliphatic diols, and process for preparing same
The present invention relates to a method for preparing a polyester carbonate starting from cycloaliphatic diacids and aliphatic diols and to the polyester carbonate prepared by the method. The method according to the invention is a direct synthesis in which all the structural elements that form the subsequent polyester carbonate are already present as monomers in the first step of the method.
1. A method for preparing a polyester carbonate by melt transesterification, comprising the steps of
(i) reacting at least one cycloaliphatic dicarboxylic acid with at least one diaryl carbonate using at least one catalyst and in the presence of at least one aliphatic dihydroxy compound and
(ii) subjecting the mixture obtained from step (i) of the method to further condensation, at least with removal of the chemical compound eliminated in the condensation,
wherein the molar ratio of all aliphatic dihydroxy compounds present in step (i) of the method to all cycloaliphatic dicarboxylic acids present in step (i) of the method prior to reaction in step (i) of the method is 1:0.6 to 1:0.05,
wherein the at least one cycloaliphatic dicarboxylic acid is selected from a compound of the chemical formula (IIa), (IIb) or mixtures thereof
in which
B in each case independently represents a carbon atom or a heteroatom selected from the group consisting of O, S and N and n is a number between 0 and 3.
2. The method according to claim 1 , wherein the at least one aliphatic dihydroxy compound is selected from the group consisting of cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, cyclohexane-1,2-dimethanol, cyclohexane-1,3-dimethanol, cyclohexane-1,4-dimethanol, tricyclodecanedimethanol, 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5] undecane, 2,2-bis(4-hydroxycyclohexyl) propane, tetrahydro-2,5-furandimethanol and 1,4:3,6-dianhydrohexitols such as isomannide, isoidide and isosorbide.
3. The method according to claim 2 , wherein the at least one aliphatic dihydroxy compound is isosorbide.
4. The method according to claim 1 , wherein the at least one cycloaliphatic dicarboxylic acid is selected from the group consisting of cyclohexane-1,4-dicarboxylic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,2-dicarboxylic acid, tetradihydro-2,5-furandicarboxylic acid, tetradihydro-2,5-dimethylfurandicarboxylic acid, decahydronaphthalene-2,4-dicarboxylic acid, decahydronaphthalene-2,5-dicarboxylic acid, decahydronaphthalene-2,6-dicarboxylic acid and decahydronaphthalene-2,7-dicarboxylic acid.
5. The method according to claim 1 , wherein the at least one diaryl carbonate is selected from the group consisting of a compound of the formula (2)
in which
R, R′ and R″ may each independently be identical or different and represent hydrogen, optionally branched C1-C34 alkyl, C7-C34 alkylaryl, C6-C34 aryl, a nitro group, a carbonyl-containing group, a carboxyl-containing group or a halogen moiety.
6. The method according to claim 5 , wherein the at least one diaryl carbonate is diphenyl carbonate.
7. The method according to claim 1 , wherein the molar ratio of the sum of all aliphatic dihydroxy compounds present in step (i) of the method and all cycloaliphatic dicarboxylic acids present in step (i) of the method to all diaryl carbonates present in step (i) of the method prior to reaction in step (i) of the method is 1:0.4 to 1:1.6.
8. The method according to claim 1 , wherein step (ii) of the method is carried out at temperatures in the range from 210° C. to 280° C.
9. The method according to claim 1 , wherein all monomers that are to undergo condensation to the polyester carbonate in step (ii) of the method are already present during step (i) of the method.
10. The method according to claim 1 , wherein the chemical compound eliminated in the condensation is removed in step (ii) of the method by means of reduced pressure.
11. The method according to claim 1 , wherein the polyester carbonate prepared has a relative solution viscosity eta rel of 1.12 to 1.60.
12. The method according to claim 1 , wherein at least one inorganic base and/or at least one organic catalyst is used in step (i) of the method.
13. The method according to claim 12 , wherein the at least one inorganic base or the at least one organic catalyst is selected from the group consisting of the hydroxides, carbonates, halides, phenoxides, diphenoxides, fluorides, acetates, phosphates, hydrogen phosphates and borates of lithium, sodium, potassium, caesium, calcium, barium and magnesium, tetramethylammonium hydroxide, tetramethylammonium acetate, tetramethylammonium fluoride, tetramethylammonium tetraphenylborate, tetraphenylphosphonium fluoride, tetraphenylphosphonium tetraphenylborate, dimethyldiphenylammonium hydroxide, tetraethylammonium hydroxide, cetyltrimethylammonium tetraphenylborate, cetyltrimethylammonium phenoxide, diazabicycloundecene (DBU), diazabicyclononene (DBN), 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-phenyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7,7′-hexylidenedi-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7,7′-decylidenedi-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7,7′-dodecylidenedi-1,5,7-triazabicyclo[4.4.0]dec-5-ene, the phosphazene base P1-t-oct (tert-octyliminotris(dimethylamino)phosphorane), the phosphazene base P1-t-butyl (tert-butyl-iminotris(dimethylamino)phosphorane) and 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diaza-2-phosphorane (BEMP).
14. A polyester carbonate obtained by the method according to claim 1 .