The Modification Of Cellulose Acetate Butyrate By Transesteriifcation And The Preparation Of Mimic Plating Coatings

Cellulose acetate butyrate (CAB) is becoming more and more important accessoryingredient in metal paint coating because it not only has the excellent metal orientation rankproperty and transparency, but also can improve leveling property and reduce drying viscosity,drying time and decrease agglomeration and shrinkage hole, and so on. However, theapplication of CAB is quite limited because of its shortcomings of low hardness, poorabrasion resistance and solvent resistance. The consumers’ demand is more and more largerwith the increasing consumers’ emphasis on surface metallization of plastics. Therefore, thestudy on mimic plating coating with excellent metallic-like appearance, high hardness, highabrasion resistance and solvent resistance has an important significance and practical value.The main research content and related achievements are as follows:First of all, the research system of directly graft modification was perfected. Graftedpolymer CAB-g-MMA was synthesized through polymerizing MMA with CAB radical whichwas initiated by solution radical polymerization method. The effect of viscosity andappearance of the resin solution on the performance of the coating was studied, the resultsindicated that the coating owns excellent composite performance and fine transparency whenthe viscosity of modified resin solution is8000~9000mpa.s, the dosage of initiator was2.0%of mass of monomer, monomer feeding speed was13g/h in nitrogen atmosphere.Moreover, remaining-OH of CAB was grafted with ester containing-C=C-bytransesterification process. The ester containing-C=C-which owns high reactivity canpolymerize with various vinyl monomers. Then, the various factors of transesterification wereresearched systematically. Modified CAB was polymerized with styrene. The feasibility ofmodifying CAB through transesterification was confirmed through the characterizationmethods such as FTIR, TG,1H NMR on product.Finally, modified CAB containing-C=C-through transesterification was polymerizedwith various acrylate monomers, and the effect of various acrylate monomers on coatingperformance was studied. In order to future improve coating performance, amino resin andPU curing agent that can make coating to take place cross-linking reaction were introducedinto coating formulation, and cross-linking reaction was characterized by FTIR, TG, et al. The prepared coating owns the best performance when the transesterification monomer wasDBMA or MMA, the mass ratio of acrylate monomers and modified CAB was1:1, andacrylate monomers contained11.6%HEMA,14.0%LMA,8.3%t-BMA but without MMA.The coating has excellent performance containing3H hardness,50times’ abrasionresistance and57times’ alcohol resistance when25%of resin mass amino resin and PUcuring agent whose mass was1/6of the resin mass and PU curing agent (dibutyltin dilaurate0.25%phr) were introduced and stoved for3h in60℃.