Patent ID: 9701851
Date: 2017-07-11
CPC Classifications: C08G,C08L,C09D

Claim:
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.