Preparation And Properties Of Silicone Modified Acrylic Waterproof Coating

Hydroxylsiloxane was synthesized by anionic ring-opening polymerization of octamethylcyclotetrasiloxane using LiOH as the catalyst. The different catalysis efficiency of LiOH and Me₃NOH was also discussed. By condensation between hydroxysiloxane and methyl dichloridesilane in the presence of triethylamine, hydrosiloxane was prepared. The active Si-H bond of the hydrosiloxane was reacted with one of the double bond in allyl raethacrylate, which produced the siloxane graft-modified AMA. Infrared spectrum was used to characterize the structure of these monomers, such as hydroxysiloxane, hydrosiloxane and Si-AMA.Si-AMA, together with methyl methacrylate, butyl acrylate, Hydroxyethyl methacrylate and γ-methyacryloxypropyltrimethoxysilane, were copolymerized in the toluene solution to obtain the siloxane modified acrylate resin. Infrared spectrum characterize the structure of the copolymer, while TG-DTA spectra testified the heat resistance of the siloxane-acrylated copolymer. Various factors influencing the inherent viscosity, molecule weight and surface tension of the copolymer resins, such as the content of Si-AMA, HEMA, KH-570 and the proportion of MMA/BA, were analyzed and discussed. Uniform design experimental method was introduced to investigate the properties of siloxane-acrylate resins, and the regressive equation of the main performances was established to optimize formation. So that the properties of the coatings could be estimated.On the base of these studies, TiO₂ was added to the copolymer resin solution to improve the anti- ultraviolet function. As a result, siloxane-acrylate coatings with good water-proofness, excellent perdurability and high heat resistance were prepared.