Catalyst compound for two-component coating compositions

• US 9,388,253 B2
• Filed: 05/03/2012
• Issued: 07/12/2016
• Est. Priority Date: 05/03/2011
• Status: Active Grant

• Current Assignee: Axalta Coating Systems Ip Co Llc (Axalta Coating Systems Ltd.)
• Original Assignee: Axalta Coating Systems Ip Co Llc (Axalta Coating Systems Ltd.)
• Inventors: Becker, Wiebke, Dreger, Katharina, Flosbach, Carmen
• Primary Examiner(s): CAMERON, ERMA C
• Application Number:
  US14/115,571
• Publication Number:
  US 20140106076A1
• Time in Patent Office: 1,531 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C08F 4/72 selected from metals not provided for in group C08F4/44 C08F4/54 - C08F4/70 take precedence
• CPC Class Codes: C08F 4/76 selected from titanium, zirconium, hafnium, vanadium, niobium or tantalum
• CPC Class Codes: C08G 18/22 containing metal compounds
• CPC Class Codes: C08G 18/244 tin salts of carboxylic acids
• CPC Class Codes: C08G 18/246 containing also tin-carbon bonds
• CPC Class Codes: C08G 18/6229 Polymers of hydroxy groups containing esters of acrylic or methacrylic acid with aliphatic polyalcohols
• CPC Class Codes: C08G 18/6258 the acid groups being esterified with polyhydroxy compounds or epoxy compounds during or after polymerization
• CPC Class Codes: C09D 175/04 Polyurethanes

Abstract

Catalyst compounds for water-based two-component coating compositions include: I) an organo-metal catalyst for a curing reaction between isocyanate groups and functional groups reactive towards isocyanate groups and II) an oligomeric or polymeric binder compound having a glass transition temperature Tg of ≧20° C., measured by DSC (differential scanning calorimetry) at a heating rate of 10 K/min. The glass transition temperature Tg of binder compound II) is above the temperature at which a water-based two-component coating composition comprising the catalyst compound is applied, preferably is at least 10° C., more preferred at least 20° C., above the temperature at which the two-component coating composition is applied.

Claims

1. A catalyst composition for water-based two-component coating compositions comprising:

an aqueous phase mixture of I) an organo-metal catalyst for a curing reaction between isocyanate groups and functional groups reactive towards isocyanate groups including for curing a reaction between at least one crosslinkable binder having at least one functional group reactive towards the isocyanate groups and at least one cross-linking agent having at least one free isocyanate group, and

II) an oligomeric or polymeric binder compound having a glass transition temperature Tg of 20 to 70°

C., measured by DSC (differential scanning calorimetry) at a heating rate of 10 K/min, wherein one or more ionic groups of the oligomeric or polymeric binder compound are neutralized with a neutralizing agent, wherein the organo-metal catalyst is immobilized in the oligomeric or polymeric binder compound, wherein the catalyst is present in the aqueous phase in oil droplets formed by the oligomeric or polymeric binder compound II), and wherein the oil droplets are separate from the at least one crosslinkable binder and the at least one cross-linking agent.

2. The catalyst composition of claim 1, wherein the glass transition temperature Tg of the binder compound II) is above the temperature at which a water-based two-component coating composition comprising the catalyst composition is applied.

3. The catalyst composition of claim 1, wherein the glass transition temperature of the binder compound II) is at least 10°

C. above the temperature at which a water-based two-component coating composition comprising the catalyst composition is applied.

4. The catalyst composition of claim 3, wherein the glass transition temperature of the binder compound II) is at least 20°

C. above the temperature at which a water-based two-component coating composition comprising the catalyst composition is applied.

5. The catalyst composition of claim 1, wherein the glass transition temperature Tg of the binder compound II) is 30 to 65°

C.

6. The catalyst composition of claim 1, comprising 0.05 to 20% by weight of catalyst I) and 99.95 to 80% by weight of binder compound II), wherein the percentages by weight are based on the total amount of the catalyst composition.

7. The catalyst composition of claim 6, comprising 0.1 to 10% by weight of catalyst I) and 99.9 to 90% by weight of binder compound II), wherein the percentages by weight are based on the total amount of the catalyst composition.

8. The catalyst composition of claim 1, wherein the catalyst I) comprises a metal salt and/or a metal complex of organic compounds.

9. The catalyst composition claim 8, wherein the metal complex comprises ligands selected from the group of beta-diketones, alkyl acetoacetates, alcoholates, and combinations thereof.

10. The catalyst composition of claim 9, wherein the metal complex comprises aluminum, titanium, zirconium or hafnium.

11. The catalyst composition of claim 8, wherein catalyst I) is an organo-tin carboxylate.

12. The catalyst composition of claim 1, wherein the binder compound II) is a (meth)acrylic copolymer, a polyester or a combination thereof.

13. The catalyst composition of claim 1, wherein the organo-metal catalyst comprises a ligand selected from the group of beta-diketones, alkyl acetoacetates, alcoholates, and combinations thereof, and a metal selected from the group consisting of aluminum, titanium, zirconium, hafnium, and combinations thereof, and wherein the oligomeric or polymeric binder compound has the glass transition temperature Tg of 30 to 65°

C.

14. A process for preparing a catalyst compound for water-based two-component coating compositions, the process comprising the steps of:

1) Preparing an oligomeric or polymeric binder compound having a glass transition temperature Tg of 20 to 70°

C., measured by DSC (differential scanning calorimetry) at a heating rate of 10 K/min (“

binder compound II)”

) in an organic medium by forming an organic solution or dispersion of the binder compound II) in one or more organic solvents,

2) Mixing the organic solution or dispersion of the binder compound II) with an organo-metal catalyst for a curing reaction between isocyanate groups and functional groups reactive towards isocyanate groups including for curing a reaction between at least one crosslinkable binder having at least one functional group reactive towards the isocyanate groups and at least one cross-linking agent having at least one free isocyanate group (“

catalyst I)”

), and

3) Converting the mixture of catalyst I) and binder compound II) into an aqueous phase by forming an aqueous dispersion or emulsion, wherein one or more ionic groups of the binder compound II) are neutralized prior to or during the conversion into the aqueous phase, wherein the catalyst I) is immobilized in the binder compound II), wherein the catalyst is present in the aqueous phase in oil droplets formed by the binder compound II), and wherein the oil droplets are separate from the at least one crosslinkable binder and the at least one cross-linking agent.

15. A method for applying a two-component coating composition containing a catalyst compound to a substrate, the method comprising the steps of:

preparing an oligomeric or polymeric binder compound having a glass transition temperature Tg of 20 to 70°

C., measured by DSC (differential scanning calorimetry) at a heating rate of 10 K/min (“

binder compound II)”

) in an organic medium by forming an organic solution or dispersion of the binder compound II) in one or more organic solvents;

mixing the organic solution or dispersion of the binder compound II) with an organo-metal catalyst for a curing reaction between isocyanate groups and functional groups reactive towards isocyanate groups including for curing a reaction between at least one crosslinkable binder having at least one functional group reactive towards the isocyanate groups and at least one cross-linking agent having at least one free isocyanate group (“

catalyst I)”

);

converting the mixture of catalyst I) and binder compound II) into an aqueous phase by forming an aqueous dispersion or emulsion, wherein one or more ionic groups of the binder compound II) are neutralized prior to or during the conversion into the aqueous phase, and wherein the catalyst I) is immobilized in the binder compound II), wherein the catalyst is present in the aqueous phase in oil droplets formed by the binder compound II), and wherein the oil droplets are separate from the at least one crosslinkable binder and the at least one cross-linking agent;

applying the aqueous phase to a substrate; and

drying and curing the aqueous phase, wherein curing comprises reacting the at least one crosslinkable binder with the at least one cross-linking agent in the presence of the catalyst I).