Study On The Preparation And Properties Of Modified Water-based Alkyd Resin

Alkyd resin is a kind of binder with relatively cheap raw material price and excellentcoating film properties. Because of these advantages, alkyd resin is still playing an importantrole in coating paint industries. With development in coating industry, the environmentalproblem arouses more attention. Therefore, it is necessary to produce a water-based alkydresin, which has superior properties and less pollution, instead of the traditional solvent-based alkyd resin.In this paper, TMA, epoxy resin, styrene and acrylate monomer were used to synthesiswater-based alkyd resins. The effect of each factor on the film properties of water-based alkydresin was discussed to confirm the optimum condition for outstanding product performance.(1) Water-based alkyd resin made by TMA: Results showed that not only the sort anddosage of raw material, but also the technological condition has an impact on productperformance. According to experimental results, using linseed oil, glycerol, phthalicanhydride, trimellitic anhydride as raw materials, LiOH as alcoholysis catalyst, controlling theratio of oil and glycerol at1/2.07, the oil length at45~50%, the excess glycol at7%, the finalacid value at50~55mg KOH/g, controlling the reaction temperature of esterification with PAstart at180oC and then rise the temperature to235oC at the rate of20oC/h, keeping thetemperature of esterification with TMA at170~180oC, using butyl cellosolve and n-butylalcohol as cosolvent and N, N-dimethylethanolamine as neutralizer, controlling the pH valueof product at7.5~8were the appropriate condition to prepared water-based alkyd resin withexcellent gloss, hardness, flexibility but poorer water tolerance and storage stability.(2) Epoxy/styrene/acrylic modified alkyd resin: The process that adding epoxy resin inthe late stage of esterification to prepare an epoxy-modified alkyd resin. Then mixed this resinwith styrene and acrylic monomers and water-based alkyd resin was obtained by the graftcopolymerization of epoxy modified alkyd and monomers. The effect of the material, initiatorand reaction temperature on product properties was discussed. And results showed that using19%of epoxy resin E-20,20%of monomers, controlling the ratio of styrene and MMA at1/1,the ratio of soft and hard monomers at1/3, controlling the acid value of product at45mgKOH/g, using BPO as initiator, keeping the temperature for copolymerization at115oC, astable water-based alkyd resin with outstanding performance of drying property, hardness,adhesion, water tolerance and salt water resistance could be prepared.