(5) Polyester resin paint

Unsaturated polyester resin is a prepolymer with unsaturated acid base such as maleic anhydride and alcohol divalent such as ethylene glycol, propylene glycol. This dissolved in reactive monomers such as styrene monomer in a slight excess of the double bond equivalent is polyester resin paint.
For instance, by adding cobalt naphthenate peroxide as accelerator as a catalyst to polyester of ethylene glycol and maleic anhydride, insoluble paint coating is formed by reactive monomer bridge bonded in the double bond of maleic acid.
This is a two-component paint where a catalyst is mixed immediately before painting. In this case, the styrene monomer acts as a solvent that gives a fluidity to the paint, and becomes the paint coating element as a bridge bonding agent. Therefore, this paint is a non-solvent paint.
The polyester paint [1] can obtain thick coating just with a single application and there is no volatilization of the solvent, [2] has hard coating with good chemical resistance and wear resistance, [3] poor adhesion with large volumetric shrinkage when hardens, [4] paint coating is poor in elastic deformity and easily scratched, [5] significantly loses luster due to exposure.

(6) Polyurethane resin paint

This is the generic name of the paint with a urethane bond in the cured coating film, and there are roughly following 4 types of commercial urethane paints.

(1) Two-component polyurethane resin paint

When isocyanate compound solution with a large number of (-NCO) isocyanate group and polyester prepolymer solution with a large number of OH groups are mixed right before painting, OH groups and NCO groups bridge react and form urethane bonding.

(2) Polyurethane resin baked paint

A 1 component baking paint composed of polyester resin and alcoholic OH group blocked isocyanate component or NCO group blocked phenol, and is baked at 180℃. It is used on urethane enamel wire, and etc.

(3) Moisture curing polyurethane resin paint

The paint with the main component of prepolymer with toluene diisocyanate (TDI) bridged with alcohol of 2-3 valence. This paint forms mesh structure paint coating by a reaction of free NCO group and moisture within the air, after painting. It cures faster with the higher air moisture similar to lacquer, and is used for lacquer-ware for that reason.

(4) Oil modified polyurethane resin paint

Urethane alkyd resin or oil modified urethane is created by reacting toluene diisocyanate (TDI) and oil modified alkyd. Curing mechanism requires the addition of a drying agent the same as oil paint. It is used in woodworking paint.