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Viscoelastic properties and coating performance of water‐soluble acrylic copolymers crosslinked with melamine resin
Author(s) -
Fukuda Tadanori
Publication year - 1995
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1995.070581101
Subject(s) - itaconic acid , copolymer , melamine resin , acrylic acid , polymer chemistry , materials science , melamine , solvent , glass transition , dynamic mechanical analysis , monomer , coating , chemistry , polymer , composite material , organic chemistry
Acrylic copolymers with different amounts of carboxyl and hydroxyl groups for obtaining practical performance of melamine‐cured acrylic coatings was investigated. Property testing results indicated that glass transition temperature ( T g ) and shear modulus increased, and molecular weight between crosslinks ( M c ) decreased with the increase of hydroxyl and carboxyl number in the acrylic copolymers. The degree of crosslinks influenced the resistance to solvent and chemicals at a lower baking temperature. Compared with acrylic acid, itaconic acid as a carboxyl monomer was more effective in inducing a lower baking schedule. The water‐soluble acrylic copolymer, which is neutralized with triethylamine, consists of 20 wt % methylmethacrylate, 55 wt % buthylacrylate, 15 wt % hydroxyethyl methacrylate, and 10 wt % itaconic acid. The copolymer showed higher crosslinks when cured with methoxymethyl melamine formaldehyde resin under a relatively lower baking schedule at 135°C for 30 min. It also has excellent solvent and chemical resistance. This coating film has a T g value of 39°C, modulus of 2 × 10 8 dyne/cm 2 in the rubbery state, and M c value of 464. Also the acrylic copolymer films with M c < 900 have good properties for solvent, acid, and alkali resistance. © 1995 John Wiley & Sons, Inc.