Core shell rubber modified solid epoxy resins

Patent metadata

Field	Value
Publication number	US-9701851-B2
Application number	US-201314425985-A
Country	US
Kind code	B2
Filing date	Oct 13, 2013
Priority date	Oct 17, 2012
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A polymer comprising: a) a thermosetting epoxy-terminated oxazolidinone ring containing polymer modified by b) core shell rubber particles, wherein at least 50% of the core shell rubber particles are prepared by a process comprising: I) carrying out an emulsion polymerization of monomers in an aqueous dispersion medium to form thermoplastic core shell rubber particles; II) coagulating the thermoplastic core shell rubber particles to form a slurry; and III) dewatering the slurry to form dewatered particles and IV) drying the dewatered particles to form dried particles is disclosed.

First claim

What is claimed is:

1. A thermosetting powder coating composition comprising a solid thermosetting epoxy-terminated oxazolidinone ring containing polymer modified by core shell rubber particles;
wherein the modified solid thermosetting epoxy-terminated oxazolidinone ring containing polymer is obtained by forming a reaction mixture and subjecting the reaction mixture to reaction conditions yielding a solid thermosetting epoxy-terminated oxazolidinone ring containing polymer having an epoxy equivalent weight of 340 to 1,000 and the core shell rubber particles dispersed therein;
wherein the reaction mixture is formed by:
providing at least one liquid epoxy resin;
dispersing the core shell rubber particles in the at least one liquid epoxy resin to form a dispersion;
adding at least one catalyst to the dispersion;
adding at least one polyisocyanate compound to the dispersion, such that a weight ratio of the at least one liquid epoxy resin to the at least one polyisocyanate compound is from 75:25 to 85:15; and
optionally adding at least one di- or multifunctional nucleophilic compound capable of forming crosslinks between epoxy groups, said optional addition is performed before or during dispersing the core shell rubber particles, before and/or after adding the at least one polyisocyanate compound, or during and/or after adding the at least one polyisocyanate compound;
wherein at least 50% of the core shell rubber particles are prepared by a process comprising:
I) carrying out an emulsion polymerization of monomers in an aqueous dispersion medium to form thermoplastic core shell rubber particles;
II) coagulating the thermoplastic core shell rubber particles to form a slurry;
III) dewatering the slurry to form dewatered particles; and
IV) drying the dewatered particles to form dried particles; and
wherein a cured thermosetting powder coating of the thermosetting powder coating composition has a glass transition temperature of at least 160° C., measured by differential scanning calorimetry according to ISO 21809-2.

2. The thermosetting powder coating composition of claim 1 wherein the at least one liquid epoxy resin is a diglycidyl ether.

3. The thermosetting powder coating composition of claim 1 wherein the dispersion has a core shell rubber content of at least 10 weight percent.

4. The thermosetting powder coating composition of claim 1 wherein the at least one polyisocyanate compound is selected from the group consisting of polymeric 4,4′-methylene bis(phenylisocyanate) (polymeric MDI) and 4,4′-methylene bis(phenylisocyanate) (MDI).

5. The thermosetting powder coating composition of claim 1 wherein the solid thermosetting epoxy-terminated oxazolidinone ring containing polymer has a ratio of oxazolidinone rings to isocyanurate rings of about 95:5 to about 100:0.

6. The thermosetting powder coating composition of claim 1 wherein the solid thermosetting epoxy-terminated oxazolidinone ring containing polymer has an epoxy equivalent weight of 360 to 1,000.

7. The thermosetting powder coating composition of claim 1 , further comprising one or more curing catalysts.

8. A substrate having thereon a fusion-bonded epoxy coating made from the thermosetting powder coating composition of claim 1 .

9. A method of making a solid thermosetting epoxy-terminated oxazolidinone ring containing polymer modified by core shell rubber particles comprising:
forming a reaction mixture and subjecting the reaction mixture to reaction conditions yielding a solid thermosetting epoxy-terminated oxazolidinone ring containing polymer having an epoxy equivalent weight of 340 to 1,000 and the core shell rubber particles dispersed therein;
wherein forming the reaction mixture comprises:
providing at least one liquid epoxy resin;
dispersing the core shell rubber particles in the at least one liquid epoxy resin to form a dispersion;
adding at least one catalyst to the dispersion;
adding at least one polyisocyanate compound to the dispersion, such that a weight ratio of the at least one liquid epoxy resin to the at least one polyisocyanate compound is from 75:25 to 85:15; and
optionally adding at least one di- or multifunctional nucleophilic compound capable of forming crosslinks between epoxy groups, said optional addition is performed before or during dispersing the core shell rubber particles, before and/or after adding the at least one polyisocyanate compound, or during and/or after adding the at least one polyisocyanate compound; and
wherein at least 50% of the core shell rubber particles are prepared by a process comprising:
I) carrying out an emulsion polymerization of monomers in an aqueous dispersion medium to form thermoplastic core shell rubber particles;
II) coagulating the thermoplastic core shell rubber particles to form a slurry;
III) dewatering the slurry to form dewatered particles; and
IV) drying the dewatered particles to form dried particles.

10. The method of claim 9 , wherein the at least one polyisocyanate compound is selected from the group consisting of polymeric 4,4′-methylene bis(phenylisocyanate) (polymeric MDI) and 4,4′-methylene bis(phenylisocyanate) (MDI).

11. The method of claim 9 wherein the at least one polyisocyanate compound is added to the dispersion in two or more steps.

12. The method of claim 9 wherein the reaction conditions comprise a temperature of at least about 150° C.

13. The method of claim 9 wherein the at least one liquid epoxy resin comprises bisphenol A diglycidyl ether.

Assignees

• Dow Global Technologies Llc

Inventors

• Aguirre Vargas Fabio

Classifications

• C08G2150/20

  Compositions for powder coatings · CPC title

• C08G59/022 Primary

  characterised by the preparation process or apparatus used · CPC title

• C08L2314/00

  Polymer mixtures characterised by way of preparation · CPC title

• C08G59/1477

  containing nitrogen · CPC title

• C08G59/26

  heterocyclic · CPC title