Synthesis And Characterization Of The Functionalized Acrylic Coating Resins

Acrylic polyurethane coating is one of the important acrylic paint species having excellent anti-chemical, weather-ability, adhesion, flexibility, anti-abrasion performance and so on. It can be widely used in the finishing and revision for the trains, cars and other products and it is one of the better development-prospect varieties in paint products. The coating was prepared by crosslinking-curing reaction with polyisocyanate and hydroxyl acrylic resin. The advantages of these two types of paints were combined in the acrylic polyurethane coating because that the urethane-acrylic ester bond and carbon-carbon long-chain were in the molecular structure, and the film is also of good fullness and decorative performance.The hydroxyl thermosetting acrylic resins with different initiator amounts and different copolymer composition were synthesized by free radical solution polymerization. The methyl methacrylate (MMA), butyl acrylate (BA), hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) were used as monomers, and the azobisisobutyronitrile (AIBN) was used as initiator in the copolymerization. The coatings’structures were studied by FTIR at first. And the effect of initiator amounts and copolymer composition on the viscosity of the polymers was discussed by an Ubbelohde viscometer. The films were prepared by hydroxyl acrylic resin curing with hexamethylene diisocyanate (HDI) trimer. And the films’structures and coating-properties were researched in this paper. The curing regular of the films were characterized by FTIR in different curing temperature and different curing time.The results show that the viscosities of the polymer were declined with the increase of AIBN. In the terpolymerization the viscosity of the terpolymer were decreased slightly with the increase of HEMA, and the viscosity of the terpolymer became flat after rose slightly with the increase of BA. In the four-unit copolymerization the viscosities of the quadripolymer were almost invariant with the increase of HEMA/AA ratio. The curing degree of the films that prepared by quadripolymer (MBHA) and HDI trimer increased gradually with curing temperature rising. The curing reaction rate reached maximum at80-100℃, and rate was up to the peak value when HEMA/AA was9/1. We can also seen that the curing rate went up with the increase of HEMA/AA, and the-NCO was consumed quickly when the functionalized monomer was all HEMA. The curing degree increased gradually with the curing time extension, and the curing reaction rate reached maximum with the increase of HEMA/AA ratio. The-NCO was consumed very fast when the functionalized monomer was all HEMA, and it was almost consumed completely in30 minutes. The hydroxyl acrylic resin that cured with HDI trimer show that the films are of excellent performance:adhesion of0-1grade, hardness of4H and the good anti-chemical and anti-heat performance.