PROCESS FOR PRODUCING A POLYESTER

Abstract

The invention relates to a process for producing a polyester by reacting a H-functional starter substance with a lactone in the presence of a catalyst, wherein the H-functional compound has one or more free carboxyl groups, wherein the lactone is a four-membered ring lactone, and wherein the catalyst is a Brönsted acid or a double metal cyanide (DMC) catalyst. The invention also relates to the polyester that can be obtained by the present invention.

Claims

1. A process for preparing a polyester comprising reacting an H-functional starter substance with a lactone in the presence of a catalyst; wherein the H-functional compound has one or more free carboxyl groups; wherein the lactone comprises a 4-membered-ring lactone; and wherein the catalyst comprises a Brønsted acid or a double metal cyanide (DMC) catalyst.

2. The process as claimed in claim 1, wherein the 4-membered-ring lactone comprises propiolactone, β-butyrolactone, diketene, preferably propiolactone and β-butyrolactone, or a mixture thereof.

3. The process as claimed in claim 1, comprising: i) initially charging the H-functional starter substance and optionally the catalyst to form a mixture i); ii) adding the lactone to the mixture i).

4. The process as claimed in claim 3, wherein the lactone is added continuously or stepwise to the mixture i) in step ii).

5. The process as claimed in claim 1, comprising: (a) initially charging the H-functional starter substance, the lactone and optionally the catalyst to form a mixture (a); (b) reacting the mixture (a) to afford the polyester.

6. The process as claimed in claim 1, wherein the H-functional starter substance having one or more free carboxyl groups comprises a monobasic carboxylic acid, a polybasic carboxylic acid, a carboxyl-terminated polyester, a carboxyl-terminated polycarbonate, a carboxyl-terminated polyether carbonate, a carboxyl-terminated polyether ester carbonate polyols and a carboxyl-terminated polyether or a mixture thereof.

7. The process as claimed in claim 1, wherein the H-functional starter substance having one or more free carboxyl groups comprises methanoic acid, ethanoic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, lactic acid, fluoroacetic acid, chloroacetic acid, bromoacetic acid, iodoacetic acid, difluoroacetic acid, trifluoroacetic acid, dichloroacetic acid, trichloroacetic acid, oleic acid, salicylic acid, benzoic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citric acid, trimesic acid, fumaric acid, maleic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid and trimellitic acid, acrylic acid, methacrylic acid, or a mixture thereof.

8. The process as claimed in claim 1, wherein the catalyst comprises a double metal cyanide (DMC) catalyst.

9. The process as claimed in claim 8, wherein the double metal cyanide (DMC) catalyst comprises an organic complex ligand, wherein the organic complex ligand comprises tert-butanol, 2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, ethylene glycol mono-tert-butyl ether and 3-methyl-3-oxetanemethanol, or a mixture thereof.

10. The process as claimed in claim 1, wherein the process is performed without addition of a solvent.

11. The process as claimed in claim 1, wherein the molar ratio of the lactone to the H-functional starter substance is from 1:1 to 30:1.

12. A polyester obtained by the process of claim 1.

13. The polyester as claimed in claim 12, wherein the polyester has a polydispersity index of ≤1.15 as determined by means of gel permeation chromatography.

14. A coating composition or adhesive composition comprising the polyester of claim 12.

Description

EXAMPLES

[0132] The present invention is more particularly elucidated with reference to the following examples without, however, being limited thereto.

Starting Materials Used

Cyclic Lactones

[0133] β-Propiolactone (bPL, purity 98.5%, Ferak Berlin GmbH)

[0134] β-Butyrolactone (bBL, purity 98%, Sigma-Aldrich Chemie GmbH)

H-Functional Starter Substance

[0135] Octane-1,8-diol (98%, Sigma Aldrich)

[0136] Adipic acid (Sigma-Aldrich, BioXtra, 99.5% (HPLC))

[0137] Citric acid (anhydrous, Sigma Aldrich, 99.5%)

[0138] Terephthalic acid (Sigma Aldrich, 98%)

Catalysts

[0139] All examples employed a DMC catalyst produced according to example 6 in WO 01/80994 A1.

Solvent

[0140] Toluene (>99.5%, Azelis Deutschland GmbH)

[0141] THF (Fisher Scientific, GPC grade)

Description of the Methods

[0142] Gel permeation chromatography (GPC): Measurements were performed on an Agilent 1200 Series (G1311A Bin Pump, G1313A ALS, G1362A RID), detection by RID; eluent: tetrahydrofuran (GPC grade), flow rate 1.0 ml/min at 40° C. column temperature; column combination: 2×PSS SDV precolumn 100 Å (5 μm), 2×PSS SDV 1000 Å (5 μm). Calibration was carried out using ReadyCal Kit Poly(styrene) low in the range Mp=266-66 000 Da from “PSS Polymer Standards Service”. The measurement recording and evaluation software used was the “PSS WinGPC Unity” software package. The polydispersity index from weighted (Mw) and number-average (Mn) molecular weight from the gel permeation chromatography is defined as Mw/Mn.

.SUP.1.H NMR

[0143] The conversion of the monomer was determined by .sup.1H NMR (Bruker DPX 400, 400 MHz; pulse program zg30, relaxation delay D1: 10 s, 64 scans). Each sample was dissolved in deuterated chloroform. The relevant resonances in the .sup.1H NMR (relative to TMS=0 ppm) and the assignment of the area integrals (A) are as follows: [0144] poly(hydroxybutyrate) (=polybutyrolactone) with resonances at 5.25 (1H), 2.61 (1H), 2.48 (1H) and 1.28 (3H). [0145] β-butyrolactone with resonances at 4.70 (1H), 3.57 (1H), 3.07 (1H) and 1.57 (3H). [0146] poly(hydroxypropionate) (=polypropiolactone) with resonances at 4.38 (2H) and 2.66 (2H) [0147] β-propiolactone with resonances at 4.28 (2H) and 3.54 (2H)

[0148] The conversion is determined as an integral of a suitable polymer signal divided by the sum of a suitable polymer signal and monomer signal. All signals are referenced to 1H.

Example 1: Preparation of a Polyester from β-Butyrolactone Using DMC Catalysis and Carboxylic Acid-Functionalized Starter (Adipic Acid)

[0149] A 300 ml steel reactor is initially charged with toluene (50.0 g), DMC catalyst (1500 ppm based on the total mass of starter and β-lactone) and adipic acid (2.92 g, 20.0 mmol, 1.00 eq.). The reactor is purged with N.sub.2. β-Butyrolactone (17.1 g, 198 mmol, 9.90 eq.) is then continuously fed into the reactor over 120 min at 130° C. The mixture is stirred for a further 120 min at 130° C. Volatile components are subsequently removed under vacuum. The molecular weight is analyzed by gel permeation chromatography (GPC) in THF. The conversion is determined by means of .sup.1H NMR analysis.

Comparative Example 1: Preparation of a Polyester from β-Butyrolactone Using DMC Catalysis and Hydroxy-Functionalized Starter (Octane-1,8-Diol)

[0150] The polymerization is effected analogously to example 1. As starter, adipic acid is replaced by octane-1,8-diol in identical mass and molar proportions.

Example 2: Preparation of a Polyester from β-Butyrolactone Using DMC Catalysis and Carboxylic Acid-Functionalized Starter (Adipic Acid)

[0151] A 300 ml steel reactor is initially charged with toluene (50.0 g), DMC catalyst (2000 ppm based on the total mass of starter and β-lactone) and adipic acid (5.84 g, 40.0 mmol, 1.00 eq.). The reactor is purged with N.sub.2. β-Butyrolactone (14.1 g, 164 mmol, 4.10 eq.) is then continuously fed into the reactor over 120 min at 130° C. The mixture is stirred for a further 120 min at 130° C. Volatile components are subsequently removed under vacuum. The molecular weight is analyzed by gel permeation chromatography (GPC) in THF. The conversion is determined by means of .sup.1H NMR analysis.

Comparative Example 2: Preparation of a Polyester from β-Butyrolactone Using DMC Catalysis and Hydroxy-Functionalized Starter (Octane-1,8-Diol)

[0152] The polymerization is effected analogously to example 3. As starter, adipic acid is replaced by octane-1,8-diol in identical mass and molar proportions.

Example 3: Preparation of a Polyester from β-Propiolactone Using DMC Catalysis and Carboxylic Acid-Functionalized Starter (Adipic Acid)

[0153] A 300 ml steel reactor is initially charged with THF (50.0 g), DMC catalyst (3000 ppm based on the total mass of starter and β-lactone) and adipic acid (2.92 g, 20.0 mmol, 1.00 eq.). The reactor is purged with N.sub.2. β-Propiolactone (17.1 g, 237 mmol, 11.9 eq.) is then continuously fed into the reactor over 120 min at 130° C. The mixture is stirred for a further 120 min at 130° C. Volatile components are subsequently removed under vacuum. The molecular weight is analyzed by gel permeation chromatography (GPC) in THF. The conversion is determined by means of .sup.1H NMR analysis.

Comparative Example 3: Preparation of a Polyester from β-Propiolactone Using DMC Catalysis and Hydroxy-Functionalized Starter (Octane-1,8-Diol)

[0154] The polymerization is effected analogously to example 1. As starter, adipic acid is replaced by octane-1,8-diol in identical mass and molar proportions.

Example 4: Preparation of a Polyester from β-Propiolactone Using DMC Catalysis and Carboxylic Acid-Functionalized Starter (Adipic Acid)

[0155] A 300 ml steel reactor is initially charged with THF (50.0 g), DMC catalyst (3000 ppm based on the total mass of starter and β-lactone) and adipic acid (5.84 g, 40.0 mmol, 1.00 eq.). The reactor is purged with N.sub.2. β-Propiolactone (14.1 g, 196 mmol, 4.90 eq.) is then continuously fed into the reactor over 120 min at 130° C. The mixture is stirred for a further 120 min at 130° C. Volatile components are subsequently removed under vacuum. The molecular weight is analyzed by gel permeation chromatography (GPC) in THF. The conversion is determined by means of .sup.1H NMR analysis.

Comparative Example 4: Preparation of a Polyester from β-Propiolactone Using DMC Catalysis and Hydroxy-Functionalized Starter (Octane-1,8-Diol)

[0156] The polymerization is effected analogously to example 3. As starter, adipic acid is replaced by octane-1,8-diol in identical mass and molar proportions.

Example 5: Solvent-Free Preparation of a Polyester from β-Propiolactone Using DMC Catalysis and Carboxylic Acid-Functionalized Starter in a Batch Process (Adipic Acid)

[0157] A 300 ml steel reactor is initially charged with DMC catalyst (3000 ppm based on the total mass of starter and β-lactone), adipic acid (14.6 g, 99.9 mmol, 1.00 eq.) and β-propiolactone (35.4 g, 491 mmol, 4.91 eq.). The reactor is purged with N.sub.2. The mixture is stirred for a further 240 min at 130° C. Volatile components are subsequently removed under vacuum. The molecular weight is analyzed by gel permeation chromatography (GPC) in THF. The conversion is determined by means of .sup.1H NMR analysis.

Example 6: Preparation of a Polyester from β-Propiolactone Using DMC Catalysis and Carboxylic Acid-Functionalized Starter (Citric Acid)

[0158] A 300 ml steel reactor is initially charged with THF (50.0 g), DMC catalyst (3000 ppm based on the total mass of starter and β-lactone) and citric acid (3.84 g, 20.0 mmol, 1.00 eq.). The reactor is purged with N.sub.2. β-Propiolactone (16.2 g, 224 mmol, 11.2 eq.) is then continuously fed into the reactor over 120 min at 130° C. The mixture is stirred for a further 120 min at 130° C. Volatile components are subsequently removed under vacuum. The molecular weight is analyzed by gel permeation chromatography (GPC) in THF. The conversion is determined by means of .sup.1H NMR analysis.

Example 7: Preparation of a Polyester from β-Propiolactone Using DMC Catalysis and Carboxylic Acid-Functionalized Starter (Terephthalic Acid)

[0159] A 300 ml steel reactor is initially charged with THF (50.0 g), DMC catalyst (3000 ppm based on the total mass of starter and β-lactone) and terephthalic acid (3.32 g, 20.0 mmol, 1.00 eq.). The reactor is purged with N.sub.2. β-Propiolactone (16.7 g, 231 mmol, 11.6 eq.) is then continuously fed into the reactor over 120 min at 130° C. The mixture is stirred for a further 120 min at 130° C. Volatile components are subsequently removed under vacuum. The molecular weight is analyzed by gel permeation chromatography (GPC) in THF. The conversion is determined by means of .sup.1H NMR analysis.

TABLE-US-00001 TABLE 1 Preparation of polyesters from β-lactones using DMC catalysis H-funct. starter x(cat) m(bPL)/m M.sub.n X(lactone) No. Lactone substance Catalyst [ppm] (starter) Solvent [g/mol] PDI [%] Ex. 1 bBL adipic acid DMC 1500 5.84 toluene 970 1.02 93 Comp. bBL octane-1,8-diol DMC 1500 5.84 toluene octane-1,8-diol, multimodal 100 ex. 1 2300, 4500 .sup.a) Ex. 2 bBL adipic acid DMC 2000 2.42 toluene 610 1.03 93 Comp. bBL octane-1,8-diol DMC 2000 2.42 toluene octane-1,8-diol, multimodal 100 ex. 2 2000, 4500 .sup.a) Ex. 3 bPL adipic acid DMC 3000 5.84 THF 1260  1.02 94 Comp. bPL octane-1,8-diol DMC 3000 5.84 THF octane-1,8-diol, multimodal 91 ex. 3 2300, 3700 .sup.a) Ex. 4 bPL adipic acid DMC 3000 2.42 THF 790 1.06 90 Comp. bPL octane-1,8-diol DMC 3000 2.42 THF octane-1,8-diol, multimodal 96 ex. 4 1900, 4000 .sup.a) Ex. 5 bPL adipic acid DMC 3000 2.42 — 580 1.08 99 Ex. 6 bPL citric acid DMC 3000 3.76 THF 1260  1.07 95 Ex. 7 bPL terephthalic acid DMC 3000 5.03 THF 1290  1.06 95 .sup.a) A multimodal molecular weight distribution is observed. Non-converted starter was identified here. The peak maxima of the polyester signals observed are also given.