POLYESTER ENAMEL Russian patent published in 2006 - IPC C09D167/00 

FIELD: varnish-and-paint industry.

SUBSTANCE: invention relates to hot-drying enamel for coloring winding material as well as building units, automobiles, and various devices. Polyester enamel comprises film-forming agent, curing catalyst, hardener, organic solvent, and pigment. Indicated film-forming agent contains: (i) 60% solution of saturated polyester resin in 3:1 Solvent/butyl glycol mixture, said resin (Uralak SN844S2G3-60) having molecular mass 4000, hydroxyl number 30-35 mg KOH/g, acid number 0-4 mg KOH/g, and vitrification temperature 19°C, and (ii) 75% Solvent solution of saturated polyester resin (Uralak SN865S2-75) having molecular mass 4500, hydroxyl number 15-30 mg KOH/g, acid number 3-7 mg KOH/g, and vitrification temperature -17°C. Curing catalysts are 40% solution of p-toluenesulfonic acid in isopropyl alcohol and 30% solution of dinonylmononaphthalenesulfonic acid in xylene. Hardener is methylated melamine-formaldehyde resin. Organic solvent contains 4:1 mixture of Solvent and n-butyl alcohol. Pigment is titanium dioxide stabilized aluminum and zirconium oxides. In addition, enamel contains mat additives: amorphous silica gel (Siloid ED-3) with particle size 5.3-6.3 μm and SiO₂ content 99% (calculated for solids) and spread agent, namely 75% solution of acrylic polymer in 4:1 mixture of Solvent and n-butyl alcohol. All components are used in specified proportions. Drying time of polyester enamel at peak metal temperature up to 249°C ranges from 65 to 72 sec. Resistance of film to methyl ethyl ketone is 140-160.

EFFECT: improved performance characteristics of enamel and films.

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