Polyester carbonates from aliphatic diacids and aliphatic diols, and process for the production thereof
The present invention relates to a process for preparing a polyester carbonate on the basis of aliphatic diacids and aliphatic diols and to the polyester carbonate prepared according to the process and to a moulding mass and moulding body containing the polyester carbonate. The process according to the invention is a direct synthesis in which all structural elements forming the subsequent polyester carbonate are already present as monomers in the first process step and in which two catalysts are used.
1 . A process for producing a polyester carbonate by melt transesterification, comprising the steps of:
(i) reacting at least one linear aliphatic dicarboxylic acid and/or at least one cycloaliphatic dicarboxylic acid with at least one diaryl carbonate in the presence of at least one aliphatic dihydroxy compound and in the presence of a first catalyst and/or a second catalyst,
(ii) subjecting the mixture obtained from process step (i) to a further condensation in the presence of the first catalyst and the second catalyst, at least with removal of the chemical compound eliminated in the condensation,
wherein the first catalyst is at least one tertiary nitrogen base,
wherein the second catalyst is at least one basic alkali metal salt,
and wherein the proportion of alkali metal cations in process step (ii) is 0.0008% to 0.0030% by weight based on all components used in process step (i).
2 . The process as claimed in 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, tetrahydrofuran-2,5-dimethanol, and 1,4:3,6-dianhydrohexitols.
3 . The process as claimed in claim 2 , wherein the at least one aliphatic dihydroxy compound is isosorbide.
4 . The process as claimed in claim 1 , wherein the at least one linear aliphatic dicarboxylic acid and/or the at least one cycloaliphatic dicarboxylic acid is a hydrogenated dimer fatty acid or is represented by the general formula (1):
in which A represents R 3 or one of formulas (Ia) or (Ib),
where R 3 represents a linear alkylene group having 3 to 16 carbon atoms, and this alkylene group may optionally be mono-or polysubstituted or
in which
B in each case independently represents a CH 2 group, O or S,
R 1 in each case independently represents a single bond or an alkylene group having 1 to 10 carbon atoms, and
R 2 in each case independently represents an alkyl group having 1 to 10 carbon atoms,
n is a number between 0 and 3,
m is a number between 0 and 6, and “*” indicate the positions at which the carboxylic acid groups in formula (1) are present.
5 . The process as claimed in claim 4 , wherein R 3 is selected from —CH 2 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —, —CH 2 —C(CH 3 ) 2 —CH 2 —, —CH 2 —CH(CH 3 )—CH 2 —C(CH 3 ) 2 —, —CH 2 —C(CH 3 ) 2 —CH 2 —CH(CH 3 )—, and —CH(CH 3 )—CH 2 —CH 2 —C(CH 3 ) 2 — and the cycloaliphatic dicarboxylic acid is hydrogenated dimer fatty acid or a compound of formula (IIa), (IIb) or mixtures thereof,
in which
B in each case independently represents a CH 2 group or a heteroatom selected from the group consisting of O and S, and n is a number between 0 and 3.
6 . The process as claimed in claim 5 , wherein the at least one cycloaliphatic dicarboxylic acid is cyclohexane-1,4-dicarboxylic acid.
7 . The process as claimed in claim 1 , wherein the at least one diaryl carbonate is selected from the group consisting of a compound of formula (2),
in which
R, R′, and R″ are each independently 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 group.
8 . The process as claimed in claim 7 , wherein the at least one diaryl carbonate is diphenyl carbonate.
9 . The process as claimed in claim 1 , wherein the first catalyst is selected from the group consisting of bases derived from guanidine, 4-dimethylaminopyridine, 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo [4.3.0]non-5-ene (DBN), 1,5,7-triazabicyclo [5.4.0]dec-5-ene and mixtures of these substances.
10 . The process as claimed in claim 1 , wherein the first catalyst is used in an amount of from 0.002% to 0.1% by weight based on all components used in process step (i).
11 . The process as claimed in claim 1 , wherein the second catalyst is selected from the group consisting of sodium phenoxide, lithium phenoxide, sodium hydroxide, lithium hydroxide, sodium benzoate, lithium benzoate, and mixtures thereof.
12 . The process as claimed in claim 1 , wherein the chemical compound eliminated in the condensation is removed in process step (ii) by means of reduced pressure.