# US 2021/0332183 A1 · Process for producing a polyester > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0332183 A1 - Document ID: US20210332183A1 - Status: Published application - Kind: A1 - Application number: 17/312,574 - Filed: 2019-12-16 - Published: 2021-10-28 - Earliest claimed: 2018-12-21 - Assignees: Covestro Intellectual Property GmbH & Co. KG - Applicants: Covestro Intellectual Property GmbH & Co. KG - Inventors: Martin Machat; Aurel Wolf; Christoph Guertler; Markus Meuresch - Web page: https://patentgrep.com/patent/US20210332183A1 ## CPC - C08G 63/08: Lactones or lactides - C08G 63/823: {for the preparation of polylactones or polylactides} - C09D 167/04: Polyesters derived from hydroxycarboxylic acids, e.g. lactones (C09D167/06 takes precedence) - C09J 167/04: Polyesters derived from hydroxycarboxylic acids, e.g. lactones (C09J167/06 takes precedence) - 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) - C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H) ## 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 ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 1) 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). ### Claim 4 (depends on 3) The process as claimed in claim 3, wherein the lactone is added continuously or stepwise to the mixture i) in step ii). ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 1) 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. ### Claim 7 (depends on 1) 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. ### Claim 8 (depends on 1) The process as claimed in claim 1, wherein the catalyst comprises a double metal cyanide (DMC) catalyst. ### Claim 9 (depends on 8) 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. ### Claim 10 (depends on 1) The process as claimed in claim 1, wherein the process is performed without addition of a solvent. ### Claim 11 (depends on 1) 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. ### Claim 12 (depends on 1) A polyester obtained by the process of claim 1. ### Claim 13 (depends on 12) 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. ### Claim 14 (depends on 12) A coating composition or adhesive composition comprising the polyester of claim 12.