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EP-4739742-A1 - LATENT CATALYST AND COATING COMPOSITIONS INCLUDING THE SAME

EP4739742A1EP 4739742 A1EP4739742 A1EP 4739742A1EP-4739742-A1

Abstract

The present disclosure provides a latent catalyst for use in two-component crosslinkable coating systems, and preferably two-component Michael addition chemistry. The latent catalyst is a salt having a structure of BR + A - wherein BR + has a structure configured, in one approach, to be deprotonated forming a carbene with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom and R thereof represents one or more substituents on the heterocyclic ring and selected from hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, alkaryl group, hydrocarbyl group, or combinations thereof. The A - moiety may be a carbonate anion, a bicarbonate anion, or a carbamate anion.

Inventors

  • XU, RUISONG
  • BANISADR, Seyedali
  • GISSER, KATHLEEN R.C.
  • BRAUN, CARL
  • Rook, Tony A.

Assignees

  • SWIMC LLC

Dates

Publication Date
20260513
Application Date
20240823

Claims (20)

  1. 1. A latent catalyst for use in two-component crosslinkable coating systems, the latent catalyst comprising: a salt having a structure of BR + A' (Formula I); wherein the BR + cation thereof has a structure configured to be deprotonated forming a carbene or an olefin with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom and R moiety thereof being one or more substituents on the heterocycle selected from hydrogen or a substituted or unsubstituted alkyl group, vinyl group, aryl group, alkaryl group, hydrocarbyl group, or combinations thereof; and wherein the A’ anion is a carbonate anion, a bicarbonate anion, a carbamate anion, or combinations thereof.
  2. 2. The latent catalyst of claim 1, wherein R is a hydrocarbyl substituent with one or more carbon atoms thereof optionally replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(R X )-, -Si(-Rx)(Ry)-, or combinations thereof, wherein R x and R y are each, independently, selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.
  3. 3. The latent catalyst of claim 1 or 2, wherein the BR cation is a 1,3-di-substituted imidazolium compound, tautomer thereof, or derivative thereof.
  4. 4. The latent catalyst of any preceding claim, wherein the 5-, 6-, or 7-membered aromatic heterocycle of the BR + cation includes a fused bi-cyclic compound, a bis-heterocyclic compound, or combinations thereof.
  5. 5. The latent catalyst of any preceding claim, wherein the two or more heteroatoms are nitrogen atoms and wherein the intermediate carbon atom is configured to form the carbene.
  6. 6. The latent catalyst of any preceding claim, wherein the BR + cation has the structure of Formula II or tautomer thereof: (Formula II) wherein each of Ri, R2, R3, and R4 is, independently, hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, or alkaryl group and R’ is hydrogen or a -CHR5R6 group, while either Rs or Re is independently hydrogen, a substituted or unsubstituted alkyl, aryl, or alkaryl group, in some occasions, Rs and Re can form a ring or Rs or Re, independently forms a ring with either Ri or R2.
  7. 7. The latent catalyst of claim 6, wherein Ri and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.
  8. 8. The latent catalyst of claim 6 or claim 7, wherein R2 and R3, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.
  9. 9. The latent catalyst of claims 6 to 8, wherein R3 and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.
  10. 10. The latent catalyst of claim 6, wherein at least one of Ri, R2, R3, and R4 is a Cl to C25 saturated or unsaturated alkyl group.
  11. 11. The latent catalyst of claim 6, wherein at least one of Ri, R2, R3, and R4 includes a substituted or unsubstituted aromatic moiety having 6 to 18 carbon atoms selected from a phenyl, a naphthyl, a phenanthryl, an anthracyl, a biphenyl, or a terphenyl group.
  12. 12. The latent catalyst of any preceding claim, wherein the BR + cation has the structure of Formula Ila or tautomer thereof: (Formula Ila) wherein each of Ri, R2, R3, and R4 is, independently, hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, or alkaryl group, each R’ is, independently, hydrogen or a -CHR5R6 group, while either Rs or Re is independently hydrogen, a substituted or unsubstituted alkyl, aryl, or alkaryl group, in some occasions, Rs and Re can form a ring or Rs or Re, independently forms a ring with either Ri or R2, and R is a hydrocarbyl group with one or more carbon atoms thereof optionally replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(R X )-, -Si(-R x )(Ry)-, or combinations thereof, wherein Rx and R y are each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.
  13. 13. The latent catalyst of claim 12, wherein Ri and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.
  14. 14. The latent catalyst of claim 12 or claim 13, wherein R2 and R3, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.
  15. 15. The latent catalyst of claims 12 to 14, wherein R3 and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.
  16. 16. The latent catalyst of claim 1, wherein BR + A’ is 1,3-dialkyl imidazolium bicarbonate or carbonate salt.
  17. 17. The latent catalyst of any one of claims 1 to 16, wherein the A' anion has the structure of Formula III (Formula III) wherein Rs is hydrogen, alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof.
  18. 18. The latent catalyst of claim 17, wherein Rs is a hydrocarbyl group and wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-R x )(R y )-, or combinations thereof, wherein R x and Ry are each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.
  19. 19. The latent catalyst of any one of claims 1 to 16, wherein the A’ anion has the structure of Formula IV (Formula IV) wherein Re and R? are each, independently, hydrogen or linear or branched alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof.
  20. 20. The latent catalyst of claim 19, wherein one or both of Re and R? is, independently, a hydrocarbyl group and wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-R x )(Ry)-, or combinations thereof, wherein Rx and Ry are each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

Description

LATENT CATALYST AND COATING COMPOSITIONS INCLUDING THE SAME CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority under 35 U.S.C 119(e) to U.S. Provisional Application No. 63/534,611, filed on August 25, 2023. The entire contents of the aforementioned application is incorporated herein. TECHNICAL FIELD [0002] This disclosure relates to latent catalysts and to coating compositions including such latent catalysts, and in particular, latent carbene catalysts for use in two-component crosslinkable coating systems. BACKGROUND [0003] Typically, crosslinkable two-component compositions are coating compositions where the components are stored separately and mixed prior to use. The two components are often highly reactive and will begin to crosslink as soon as they are mixed. It is conventional to include a catalyst in such coating systems to increase the rate of the crosslinking reaction between the two components. [0004] The crosslinking reaction may be base-catalyzed or acid-catalyzed. Base-catalyzed systems are sometimes preferred because they are capable of a fast cure. However, because of the rapid rate of cure, prior base-catalyzed compositions can only be used for a relatively short period of time after the components are mixed, defined as the pot-life of the coating composition. In some base-catalyzed systems, viscosity increases so rapidly that the coating starts to cure before it can be fully applied to a surface, and accordingly, these systems are of limited practical use. [0005] For waterborne systems where viscosity may not be a good indicator for pot-life, the hardness and/or the gloss level of applied coatings at various times may be used a measure of pot life. Due to concerns regarding the use of volatile organic compounds (VOC) in coatings, high solids systems with low solvent content or even waterborne systems substantially free of solvent are oftentimes preferred. However, such systems present several additional challenges with regard to balancing pot-life, hardness/gloss, and kinetics of cure or dry speed. For example, a high solids composition typically includes less solvent that can evaporate when the coating is applied, and as a result, the pot-life is much lower than preferred. [0006] On the other hand, the increase in reaction rate when the coating is applied is also reduced with less solvent in the system, leading to slower cure. Thus, a combination of rapid cure and long pot-life is often challenging to achieve for two-component, high-solids solvent borne coating systems and/or for waterborne systems where the reaction may occur in the dispersion phase. Thus, a further challenge in two-component crosslinkable systems, both solvent borne and waterborne, using latent catalysts is the cure kinetics at room temperature or lower bake conditions of about 100°C or less. Prior systems using latent base catalysts oftentimes required too high of an activation temperature for such systems to have cure kinetics practicable at the lower room temperature or low bake conditions. In some prior systems, the latent catalyst may also be blocked to provide desired pot life. However, blocked catalysts also provide challenges. For instance, blocked catalysts tend to deposit or leave salts in a dried coating film that, in some circumstances, may degrade coating performance. In other instances, only the anionic portion of a blocked catalyst after the de-blocking acts as a base for catalyzing the reaction tending to limit the cure mechanisms. SUMMARY [0007] In one approach or embodiment, the present application describes a latent catalyst for use in two-component crosslinkable coating systems, and in one aspect, a latent carbene catalyst and, in another aspect, a latent N-heterocyclic olefin catalyst. In aspects of this approach, the latent carbene catalyst includes a salt having a structure of BR A (Formula I); wherein the BR cation thereof has a structure configured to be deprotonated forming a carbene with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom and R moiety thereof being one or more substituents on the heterocycle selected from hydrogen or a substituted or unsubstituted alkyl group, vinyl group, aryl group, alkaryl group, hydrocarbyl group, or combinations thereof; and wherein the A' anion is a carbonate anion, a bicarbonate anion, a carbamate anion, a carboxylate, or combinations thereof. In other aspects, the BR+ cation has a structure configured to form a N-heterocyclic olefin including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom and R moiety thereof being one or more substituents on the 2 57068427 2 heterocycle selected from hydrogen or a substituted or unsubstituted alkyl group, vinyl group, aryl group, alkaryl group, hydrocarbyl group, or combinations thereof. [0008] In other approaches or embodiments, the latent catalyst, t