Preparation And Research Of Waterborne Anticorrosion Coatings

With the increasingly stringent environmental protection regulations,waterborne anti-corrosion coatings have become a hot topic in the research of anti-corrosion coatings in recent years because of the low VOC characteristics.In this paper,acrylic graft-modified epoxy resin water dispersion and high hydroxyl value acrylic resin water dispersion were prepared by self-made water-borne resin.Then,practical waterborne epoxy anticorrosive primer and waterborne polyurethane anticorrosive topcoat were prepared.The effects of preparation process and synthesis conditions on the stability and properties of aqueous dispersions were investigated;the effects of the type of curing agent,the amount of curing agent used,the PVC value,the type and amount of pigments,and the activation period on the properties of the paint film were explored.Firstly,a water-borne acrylic graft-modified epoxy dispersion was prepared,and used to make a waterborne epoxy anticorrosive primer.The results of the study were as follows: BPO was used as the initiator,butanol/BCS was used as the initiator.Under the conditions of mixed solvent,115°C and 4.5h reaction,the system acid value is 85mgKOH/g and the degree of neutralization is 80-90%,and a stable epoxy dispersion can be prepared with an average particle size of 184.4nm.After compounding study,the dispersion and 901 curing agent with epoxy/amine hydrogen molar ratio of 1.2:1,PVC value of 50%,after the compounding,the activation period is 4h,the paint film surface defects,hardness of 2H,Impact resistance>50Kg·cm,finger dry time 3h,salt spray resistance more than 550 h.Next,a high hydroxyl value acrylic acid aqueous dispersion was prepared to make an aqueous bright anticorrosive topcoat.The results of the study were as follows: AIBN was used as an initiator,MEK/BCS was a mixed solvent,and the reaction conditions were 5 hours at 80°C.The hydroxyl value is 22.5 mgKOH/g,and the degree of neutralization is 90%,and a stable aqueous hydroxypropyl dispersion can be prepared with an average particle size of 91.53 nm.After compounding studies,the high hydroxyl dispersion does not match Bayhydur XP 2655 curing agent,which is commonly used in water-based preservation.The film-forming effect is poor,and the 105 curing agent with low NOC content and low activity has an NCO/OH molar ratio of 1.5: 1.When the PVC value is 15.35%,after the compounding,the activation period is 3h,the gloss of the film exceeds 85°,the hardness is 2H,the impact resistance is >50Kg·cm,and the finger pressure drying time is 3h.A highly decorative water-based anticorrosive finish is prepared.With self-made water-based anti-corrosion primer,composite coating resistance to salt spray more than 1000 h.