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US-12617892-B2 - Application of the ring-opening of uretdiones at low temperature and ambient atmosphere

US12617892B2US 12617892 B2US12617892 B2US 12617892B2US-12617892-B2

Abstract

A process for preparing a polymer containing a structural element —N—C(═O)—X 2 — involves: (a) providing an uretdione of formula (I), and (b) opening a ring of the uretdione at a temperature greater than 50° C. and in the presence of a catalyst composition containing at least one catalyst, to obtain the polymer. In the element —N—C(═O)—X 2 , X 2 is a derivative of the group X 1 reactive towards isocyanates. The polymer containing the element —N—C(═O)—X 2 — obtained from the process is useful. A method for modifying polymers which have reactive groups towards isocyanate groups involves: (i) providing a polymer having at least one functional group reactive towards isocyanate groups; (ii) providing an uretdione, of formula (II); and (iii) reacting the polymer with the uretdione at a temperature of more than 50° C., in the presence of a catalyst composition containing at least one catalyst. The modified polymer obtained according to the method is useful.

Inventors

  • Aggeliki QUELL
  • Florian Ludwig GEYER

Assignees

  • BASF SE

Dates

Publication Date
20260505
Application Date
20210722
Priority Date
20200723

Claims (18)

  1. 1 . A process for preparing a polymer comprising a structural element —N—C(═O)—X 2 —, the process comprising: (a) providing an uretdione of formula (I) wherein R 1 is selected from the group consisting of: branched and unbranched C1 to C20-alkylene groups; substituted and unsubstituted C4 to C20-cycloalkyl groups, wherein a substituted C4 to C20-cycloalkyl group has one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups, wherein each C4 to C20-cycloalkyl group is either directly bonded to Y 1 or is bonded via a CH 2 group to Y 1 , and is either directly bonded to the nitrogen atom of the uretdione structure or via a CH 2 group; C1 to C5 alkyl-bridged dicyclohexyl groups; substituted and unsubstituted C6 to C14-aryl groups, wherein a substituted C6 to C14-aryl group has one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups; C1 to C5-alkyl-bridged di-C6 to C14-aryl groups, wherein each C6 to C14-aryl group is unsubstituted or substituted with one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups; X 1 is a group reactive towards isocyanates, Y 1 is a linker group, wherein Y 1 is absent or selected from the group consisting of —NH—C(═O)—[R 2 —]—, —NH—C(═O)—O—[CH 2 ] n —, —NH—C(═O)—O—[R 1 ] n —, each with the nitrogen-atom being attached to R 1 , —[CH 2 ] n —, —[R 2 ]—, —NH—C(═O)—NH—[R 1 ] n —, —[R 1 ] n —, —NH—C(═O)—NH-cyclohexyl-, which has at least one CH 3 group on the cyclohexyl ring, —NH-cyclohexyl-, which has at least one CH 3 group on the cyclohexyl ring, —NH—C(═O)—NR 3 —[R 1 ] n —, —[R 1 ] n —, —NH—C(═O)—NR 3 -cyclohexyl which has at least one CH 3 group on the cyclohexyl ring, —NR 3 -cyclohexyl-, which has at least one CH 3 group on the cyclohexyl ring, and R 1 ; wherein R 1 is as defined above, R 2 is a polyetherpolyol residue having on each side a terminal oxygen atom based on ethylene oxide, propylene oxide, butylene oxide, or a mixture thereof, with 1-100 repeating units, or —[(CH 2 ) 4 —O] r — with r being an integer in the range of from 1-100; or a mixture of polyetherpolyol residues having on each side a terminal oxygen atom based on ethylene oxide, propylene oxide, butylene oxide, or a mixture thereof with p repeating units, and —[(CH 2 ) 4 —O] r , wherein a sum of p and r is an integer in the range of from 1-100, R 3 is selected from the group consisting of methyl group, ethyl group, propyl group, isopropyl group, butyl group, iso-butyl group, ethyl hexyl group, and benzyl group; and n is zero or an integer in the range of from 1 to 12; and (b) ring opening the uretdione of formula (I) provided according to (a) at a temperature of more than 50° C., in the presence of a catalyst composition comprising at least one catalyst C, wherein the at least one catalyst C comprises one or more ionic liquids, which are salts of the following formula (I) [ A ] n + [ Y ] n - , ( I ) wherein n is an integer in the range of from 1 to 4; [A] + is a quaternary ammonium cation, which comprises a five or six membered heterocycle, which comprises at least one nitrogen atom and optionally an oxygen atom or a sulfur atom, wherein the nitrogen atom of the heterocycle is quaternised with t C 1 -C 18 alkyl residues; and [Y] n− is a mono-, di-, tri-, or tetra-valent anion; thereby obtaining the polymer comprising the structural element —N—C(═O)—X 2 , wherein X 2 is a derivative of the group X 1 reactive towards isocyanates; and wherein the one or more ionic liquids are combined with one or more co-catalyst, wherein the one or more co-catalyst is selected from the group consisting of organometallic catalyst, tertiary amine catalyst, and a mixture of organometallic catalyst and tertiary amine catalyst.
  2. 2 . The process according to claim 1 , wherein in the uretdione of formula (I), X 1 is a hydroxyl group and Y 1 is selected from the group consisting of —NH—C(═O)—[R 2 ]—, —NH—C(═O)—O—[CH 2 ] n —, —NH—C(═O)—O—[R 1 ] n —, —[CH 2 ] n —, and —[R 2 ]—, wherein n, R 1 , and R 2 are as defined in claim 1 ; or X 1 is a NH 2 group and Y 1 is selected from the group consisting of —NH—C(═O)—NH—[R 1 ] n —, —[R 1 ] n —, —NH—C(═O)—NH-cyclohexyl-, which has at least one CH 3 group on the cyclohexyl ring, and —NH-cyclohexyl, which has at least one CH 3 group on the cyclohexyl ring, wherein n and R 1 are as defined in claim 1 ; or X 1 is a NHR 3 group and Y 1 is selected from the group consisting of NH—C(═O)—NR 3 —[R 1 ] n —, —[R 1 ] n —, —NH—C(═O)—NR 3 -cyclohexyl which has at least one CH 3 group on the cyclohexyl ring, and —NR 3 -cyclohexyl-, which has at least one CH 3 group on the cyclohexyl ring, wherein n, R 1 , and R 3 are as defined in claim 1 .
  3. 3 . The process according to claim 1 , wherein in the uretdione of formula (I), R 1 is selected from the group consisting of —[CH 2 ] m — group with m being an integer in the range of from 3 to 20, 1,2-phenylene group, 1,3-phenylene group, and 1,4-phenylene group, optionally substituted with one or more substituents selected from the group consisting of methyl group, cyclohexylene, and CH 2 -cyclohexylene group, wherein a cyclohexylene ring of the cyclohexylene or CH 2 -cyclohexylene group is optionally substituted with one or more methyl groups, and —CH 2 -bridged di-C6-aryl group.
  4. 4 . The process according to claim 1 , wherein (b) is conducted at a pressure in the range of from 500 to 2000 mbar.
  5. 5 . The process according to claim 1 , wherein (b) is conducted in an atmosphere comprising more than 5 volume-% of oxygen, based on a total composition of the atmosphere, or wherein (b) is conducted in a protective atmosphere.
  6. 6 . The process according to claim 1 , wherein the one or more ionic liquids in the at least one catalyst C comprised in the catalyst composition is selected from the group consisting of 1-ethyl-3-methyl imidazolium bromide (EMIM-Br), 1-benzyl-3-methyl imidazolium chloride (BEMIM-Cl), 1-butyl-1-methylpiperidinium chloride (BMPM-Cl), 1-ethyl-2,3-dimethylimidazolium bromide (EDMIM-Br), 1-(2-hydroxyethyl)-3-methyl imidazolium chloride (HEMIM-Cl), butyl-1-methylpiperidinium acetate (BMPM acetate), and a mixture of two or more thereof.
  7. 7 . A polymer comprising the structural element —N—C(═O)—X 2 —, obtained from the process according to claim 1 .
  8. 8 . A method for modifying polymers, which have reactive groups towards isocyanate groups, the method comprising: (i) providing a polymer having at least one functional group reactive towards isocyanate groups; (ii) providing an uretdione of formula (II) wherein R 4 is a Y 2 —R 5 group, wherein Y 2 is a single oxygen atom —O—, or Y 2 is —NR 3 — with R 3 being selected from the group consisting of hydrogen atom, methyl group, ethyl group, propyl group, isopropyl group, butyl group, iso-butyl group, ethyl hexyl group, and benzyl group; and R 5 is selected from the group consisting of branched and unbranched C1 to C20-alkylene groups; substituted and unsubstituted C3 to C20-cycloalkyl groups, wherein a substituted C3 to C20-cycloalkyl group has one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups, wherein each C3 to C20-cycloalkyl group is either directly bonded to Y 2 or is bonded via a CH 2 group to Y 2 ; substituted or unsubstituted C6 to C14-aryl groups, wherein a substituted C6 to C14-aryl group has one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups; C1 to C5-alkyl-bridged di-C6 to C14-aryl groups, wherein each C6 to C14-aryl group is unsubstituted or substituted with one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups; and isobornyl, bornyl, and menthyl; or R 4 is selected from the group consisting of: acrylate and methacrylate, an esterification product of diol with acrylic acid and/or methacrylic acid; wherein the diol is selected from the group consisting of ethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, butane-2,3-diol, pentane-1,2-diol, pentane-1,3-diol, pentane-1,4-diol, pentane-1,5-diol, pentane-2,3-diol, pentane-2,4-diol, hexane-1,2-diol, hexane-1,3-diol, hexane-1,4-diol, hexane-1,5-diol, hexane-1,6-diol, hexane-2,5-diol, heptane-1,2-diol 1,7-heptanediol, 1,8-octanediol, 1,2-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,2-decanediol, 1,12-dodecanediol, 1,2-dodecanediol, 1,5-hexadiene-3,4-diol, cyclopentanediol, cyclohexanediol, cyclohexane dimethanol, isosorbitol, hydroxypivalinic acid neopentylglycol ester, inositol, inositol derivative, (2)-methyl-2,4-pentanediol, 2,4-dimethyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, pinacol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, difunctional polyetherpolyol based on ethylene oxide, propylene oxide, butylene oxide, and a mixture thereof, with 1-100 repeating units; an esterification product of polytetrahydrofuran with acrylic acid and/or methacrylic acid with 1-100 repeating units, an esterification product of acrylic acid and/or methacrylic acid with at least one polyol having three or more hydroxyl groups, and a mixture of two or more thereof; R 1 is selected from the group consisting of: branched and unbranched C1 to C20-alkylene groups; substituted and unsubstituted C4 to C20-cycloalkyl groups, wherein a substituted C4 to C20-cycloalkyl group has one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups, wherein each C4 to C20-cycloalkyl group is either directly bonded to the nitrogen atom of the —NH— unit or is bonded via a CH 2 group to the nitrogen atom of the —NH— unit, and is either directly bonded to the nitrogen atom of the uretdione structure or via a CH 2 group; C1 to C5 alkyl-bridged dicyclohexyl groups; substituted and unsubstituted C6 to C14-aryl groups, wherein a substituted C6 to C14-aryl group has one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups; C1 to C5-alkyl-bridged di-C6 to C14-aryl groups, wherein each C6 to C14-aryl group is unsubstituted or substituted with one or more substituents independently selected from the group consisting of branched and unbranched C1 to C8-alkyl groups; (iii) reacting the polymer having at least one functional group reactive towards isocyanate groups of (i) with the uretdione of formula (II) of (ii) at a temperature of more than 50° C., in the presence of a catalyst composition comprising at least one catalyst C, wherein the at least one catalyst C comprises one or more ionic liquids, which are salts of the following formula (I) [ A ] n + [ Y ] n - , ( I ) wherein n is an integer in the range of from 1 to 4; [A] + is a quaternary ammonium cation, which comprises a five or six membered heterocycle, which comprises at least one nitrogen atom and optionally an oxygen atom or a sulfur atom, wherein the nitrogen atom of the heterocycle is quaternised with t C1-C18 alkyl residues; and [Y] n− is a mono-, di-, tri-, or tetra-valent anion.
  9. 9 . The method for modifying polymers having reactive groups towards isocyanate groups according to claim 8 , wherein in the uretdione of formula (II), R 1 is selected from the group consisting of an unbranched C3 to C20-alkylene group, [CH 2 ] m -group with m being an integer in the range of from 3 to 20, 1,2-phenylene group, 1,3-phenylene group, and 1,4-phenylene group, optionally substituted with one or more substituents selected from the group consisting of methyl group, cyclohexylene, and —CH 2 -cyclohexylene group, wherein a cyclohexylene ring of the cyclohexylene or CH 2 -cyclohexylene group is optionally substituted with one or more substituents selected from the group consisting of methyl group and —CH 2 -bridged di-C6-aryl group.
  10. 10 . The method for modifying polymers having reactive groups towards isocyanate groups according to claim 8 , wherein (ii) is conducted at a pressure in the range of from 500 to 2000 mbar; and/or wherein (ii) is conducted in an atmosphere comprising more than 5 volume-% of oxygen, based on a total composition of the atmosphere.
  11. 11 . The method for modifying polymers having reactive groups towards isocyanate groups according to claim 8 , wherein the one or more ionic liquids in the at least one catalyst C comprised in the catalyst composition is selected from the group consisting of 1-ethyl-3-methyl imidazolium bromide (EMIM-Br), 1-benzyl-3-methyl imidazolium chloride (BEMIM-Cl), 1-butyl-1-methylpiperidinium chloride (BMPM-Cl), 1-ethyl-2,3-dimethylimidazolium bromide (EDMIM-Br), 1-(2-hydroxyethyl)-3-methyl imidazolium chloride (HEMIM-Cl), butyl-1-methylpiperidinium acetate (BMPM acetate), and a mixture of two or more thereof.
  12. 12 . The method for modifying polymers having reactive groups towards isocyanate groups according to claim 11 , wherein the at least one catalyst C comprises the one or more ionic liquids and one or more co-catalyst, wherein the one or more co-catalyst is selected from the group consisting of organometallic catalyst, tertiary amine catalyst, and a mixture of organometallic catalyst and tertiary amine catalyst.
  13. 13 . A modified polymer, obtained according to the method of claim 8 .
  14. 14 . The process according to claim 1 , wherein in the structural element —N—C(═O)—X 2 , X 2 is selected from the group consisting of oxygen atom (—O—), —NH— group, and —NR 3 —; wherein R 3 is selected from the group consisting of methyl group, ethyl group, propyl group, isopropyl group, butyl group, iso-butyl group, ethyl hexyl group, and benzyl group.
  15. 15 . The process according to claim 3 , wherein R 1 is selected from the group consisting of wherein dotted lines represent bonds towards Y 1 and towards the nitrogen atom of a central uretdione structure.
  16. 16 . The process according to claim 5 , wherein (b) is conducted in an inert gas atmosphere, wherein the inert gas selected from the group consisting of helium, neon, argon, krypton, xenon, nitrogen, and a mixture of two or more thereof.
  17. 17 . The method for modifying polymers having reactive groups towards isocyanate groups according to claim 8 , wherein the polymer in (i) has at least two functional groups which are reactive towards isocyanate groups.
  18. 18 . The method for modifying polymers having reactive groups towards isocyanate groups according to claim 9 , wherein R 1 is selected from the group consisting of wherein dotted lines represent bonds towards a —NH— unit and towards the nitrogen atom of a central uretdione structure.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is the National Stage entry under § 371 of International Application No. PCT/EP2021/070555, filed on Jul. 22, 2021, and which claims the benefit of priority to European Application No. 20187450.0, filed on Jul. 23, 2020. The content of each of these applications is hereby incorporated by reference in its entirety. BACKGROUND OF THE INVENTION Field of the Invention In a first aspect, the invention relates to a process for preparing a polymer comprising a structural element —N—C(═O)—X2—, wherein the process comprises (a) Providing an uretdione of formula (I) and (b) ring opening of the uretdione of formula (I) provided according to (a) at a temperature of more than 50° C., and in the presence of a catalyst composition comprising at least one catalyst C, thereby obtaining a polymer comprising a structural element —N—C(═O)—X2, wherein X2 is a derivative of the group X1 reactive towards isocyanates. A second aspect of the invention relates to a polymer comprising a structural element —N—C(═O)—X2— obtained or obtainable from the process according to the first aspect. A third aspect of the invention is directed to a method for modifying polymers, which have reactive groups towards isocyanate groups, the method comprising: (i) providing a polymer having at least one, preferably at least two, functional groups which are reactive towards isocyanate groups; (ii) providing an uretdione of formula (II); and (iii) reacting the polymer having at least one functional group reactive towards isocyanate groups of (i) with the uretdione of formula (II) of (ii) at a temperature of more than 50° C., in the presence of a catalyst composition comprising at least one catalyst C. In a fourth aspect, the invention relates to a modified polymer obtained or obtainable according to the method of the second aspect. A fifth aspect of the invention relates to an uretdione of formula (II) as defined in view of the method of the second aspect. Description of Related Art The synthesis of toluene diisocyanate-uretdione (TDI-uretdione) has long been described in literature [A. Davis, Dimerisation and Trimerisation of 2,4 Tolylene Di-isocyanate, Die Makromolekulare Chemie, 1963, 196-204]. 2,4-TDI reacts with itself to TDI-uretdione. The reaction is reversible at high temperature. The potential for a selective addition chemistry to TDI has likewise been long noted. Singh and Boivin [P. Singh, J. L. Boivin, Canadian Journal of Chemistry, 1962, 935-940] described the syntheses of several bisadducts from TDI with urea and carbamate moieties by reacting both NCO from TDI-uretdione with amines or alcohols. Risch et al. [N. Risch, U. Westerwelle, J. Kiene, R. Keuper, Preparation, Characterization and Selective Reactions of Novel [1,3]Diazetidine-2,4-diones (Uretdiones)—A New Route to Generate Assymetric Substituted Toluylenediisocyanate-Derivatives, J. Prakt. Chem, 1999, 341, 616-619] demonstrate the usage of the uretdione-ring as a protected NCO-group and selectively cleave the 4-membered ring under presence of another nucleophile and a phosphine catalyst. US 2010/298490 A1 discloses a method of making an oligomer, comprising reacting one mole of a uretdione compound. Inter alia, a hydroxyl propyl carbamate-capped hexamethylene diisocyanate (HDI) urethdione is ring-opened using zinc acetylacetonate hydrate as catalyst. US 2006/052527 A1 discloses a process for preparing a binder. An urethane acrylate containing uretdione groups is prepared by using an HDI uretdione which is reacted with 2-HEA. The urethane acrylate containing uretdione groups is further reacted with a polyether triol in the presence of zinc(II)ethylhexanoate as catalyst, thereby resulting in a ring-opening of the uretdione groups. US 2010/152404 A1 discloses a process for preparing a carboxyl functional polyuretdione resin composition; zinc hexadecanoat, tin hexadecanoat, zinc acetylacetonate, and zinc acetate are described as suitable catalysts. Querat et al. [E. Querat, L. Tighzert, J. P. Pascault, K. Dusek, Die Angewandte Makromolekulare Chemie, 242, 1996, 1-36] shortly review the synthesis of uretdiones by catalysis with phosphines or a mixture of pyridine with triethylamine before studying the thermal dissociation without a catalyst and with three different potential catalysts. Without catalyst, the hydroxyl group (OH) of polycaprolactone reacted with free isocyanate (NCO) of the TDI-dimer between 90-150° C. The ring-opening and reaction with the OH functions of the polycaprolatone with the uretdione/regenerated NCO could be found between 160-220° C. The authors also showed that upon storage in mixture with polycaprolactone at 40° C. for 8 days, no uretdione ring opening occurred. Triethylamine (TEA), tributylphosphine (TBP) and dibutyltin dilaureate (DBTL) were compared for the reaction of TDI-uretdione with polycaprolactone and examined by DSC. Two distinct reactions could be observed with TEA and TBP. Triethylamine perfo