Coemulsion and electrodeposition properties of mixtures of cationic epoxy resin and cationic acrylic resin containing blocked‐isocyanate groups

Abstract

SYNOPSIS2-Ethylhexanol-half-blocked-toluene diisocyanate ( 2EH-half-blocked TDI) was first reacted with 2-hydroxyethyl methacrylate (HEMA) to prepare HEMA-TDI-2EH monomer containing blocked-isocyanate groups. This monomer was reacted with butyl acrylate, styrene, and N,N-dimethylaminoethyl methacrylate to prepare an acrylic copolymer 111' containing blocked-isocyanate groups and tertiary amine groups. The acrylic copolymer 111' can be mixed with a n epoxy-amine adduct IV', acetic acid, and deionized (D.I.) water to form an electrodepositable coemulsion. The electrophoretic codeposition of the coemulsion and physical and chemical properties of the codeposited film were investigated. The resin composition of film deposited from coemulsion was determined by Fourier transform infrared ( FTIR ) quantitative analysis to study the coemulsion and electrophoretic codeposition behavior. The applicability of this two-component coemulsion in primer-surface (pricer) electrodepositable paint was also discussed. The results indicate that the deposition yield of cationic acrylic copolymer I11 is greater than that of cationic epoxy resin IV, i.e., the deposition velocity of I11 is faster than that of IV. However, resins I11 and IV can be well codispessed in D.I. water to form stable coemulsions; thus, the resin composition of deposited is almost equal to the coemulsion resin composition. Moreover, the throwing power of coemulsion is almost equal to that of IV emulsion but greater than that of I11 emulsion. The optimum resin compositions of coemulsions for obtaining better gel content of deposited films are between 0.65 and 0.8

Synthesis, characterization and properties of amphiphilic block copolymers of 2-hydroxyethyl methacrylate and polydimethylsiloxane prepared by atom transfer radical polymerization

“…10 Poly(2-hydroxyethyl methacrylate) is hydrophilic acrylic polymer with unique assets, including transparency, good mechanical properties and biocompatibility. The pHEMA hydroxyl groups can be crosslinked with melamine-formaldehyde (M-F) resins, isocyanates 11 and epoxides. 12 Flexible and high-gloss polymer films were prepared by curing 2-Hyroxyethyl methacrylate (HEMA)-modified polysiloxane.…”