Research On The Polyester Resin Modified By Titanium-doped Silicone And The Application In The Coating With Highly Heating-resistant And Anticorrosive

In order to prevent oxidation erosion of the metal products and prolong service life of the equipments under high temperature, the coatings with highly heating-resistant and anticorrosive are widely used in the fields of electron, light industry, chemical industry, aerospace and so on, such as decorations of steel smoke tailpipes, stoves, petroleum cracking units, high temperature equipments and military equipments.In this paper, a kind of titanium-doped silicone resin(TDS) which has active functional group was prepared by the partial hydrolysis-condensation of Tetra-n-butyl titanate, methyltriethoxysilane, dimethyldiethoxysilane and phenyltriethoxysilane. After the research of the proportion of monomer, the catalysis system, the reaction conditions of the production, the optimum technological conditions were obtained in this test as follow: hydrochloric acid used as catalyst, R/Si=1.44, Ph/R=0.21, the hydrolysis temperature 65℃, the rotating speed 140 rpm. The structure of titanium-doped silicone resin was characterized by FT-IR and the heat resistant performance was tested by TGA. The results showed that, when the molar ratio of Ti to Si was 1:4 in reactants, the thermal stability of the titanium-doped silicone resin was best and the heat temperature of synthesized was up to 450-500℃A novel series of hydroxyl-terminated saturated polyester resins(HTSP) for coating was synthesized by solution polycondensation method of m-phthalic acid, adipic aid, dineopentyl alcohol, diglycol and trimethylolpropane. The polyester resin modified by titanium-doped silicone for coating was synthesized by esterification of titanium-doped silicone prepolymer with hydroxyl-terminated saturated polyester resin. Both the copolymerization and blending reaction were adopted. Infrared spectrum diagram analysis showed that the oxyethyl group in the polyester modified by copolymerization was disappeared. The weight-average molecular weight of modified polyester was increased, which indicated that the titanium-doped silicone is combined with the polyester to form a polymer. It was also found that the thermal stability of polyester resins modified by titanium-doped silicone through copolymerization increased more obviously than that through blending.The mechanical capacity and antiseptic property of the coating film prepared with iron panel were tested respectively. The research found that the coating possess the best mechanical properties and anti-corrosion properties when the mass ratio of the titanium-doped silicone and the polyester was 1:1. The properties of the coating were as follow:the pencil hardness,5 H; the adhesion,1 level; the impact resistance, more than 50 kg-cm; the boiling water resistance,5 h; the acid resistance,90 d; the alkali resistance,30 d; the resistance to alternating hot and cold,40 cycles; the heat-resistance temperature,400℃, the coating resistance,2.0×108Ω·cm, which improves two orders of magnitude than that before modification. Electron microscopy analysis showed that the improvement of performance is owing to the increased crosslinking density and the coating became dense and uniform when titanium-doped silicone chain was connected to the polyester.The titanium-doped silicone modified polyester resin (mass ratio 1:1) was used as film forming matter; titanium pigment, zinc phosphate, pulverized soap stone and bentonite were used as pigments and fillers; fumed silica, KH560, dibutyl tin laurate were used as rheological agent, silane coupling agent and drier of the high-temperature resistant and anticorrosion coating. The performance detection of the coating film prepared with iron panel showed that when the content of titanium dioxide was 40%, the properties of coating as follow:the boiling water resistance 6 h; the acid resistance 100 d; the alkali resistance 40 d; the resistance to alternating hot and cold 50 cycles; the heat-resistance temperature 400℃; the solvent-acetone resistance 24 h; the salt fog resistance 300 h. The corrosion resistance of the coating improved significantly when zinc phosphate was added.