Synthesis Of Reactive Disperse Silicon-containing Dyes And Coloration On Silicone Rubbers

Silicone rubbers have been extensively used in medicine,aviation and aerospace fields,electric wires and cables,electronics and electric appliances,and automobiles and machines due to their high and low temperature-resistance,aging resistance,oil resistivity and chemical resistance.Silicone rubbers should be colored in healthcare and electric wires and cables fields.Silicone rubbers' colorants include inorganic pigments and organic pigments.Inorganic pigments are mainly metal oxides.But their tone ranges are narrow,they are not bright,and the costs of inorganic pigments are expensive.Some inorganic pigments contain heavy metals.Heavy metals have the risk of ecological environment and human compatibility.Organic pigments have bright colors and strong dyeing power,but both pigments are dispersed in the form of particles in silicone rubbers.For solving above problems,this paper designed and synthesized reactive disperse silicon-containing dyes for coloring of silicone rubbers.Novel yellow,red and purple reactive disperse silicon-containing dyes were designed and synthesized using p-nitroaniline and 2,4-dinitro-6-bromo-aniline as diazonium components,the first condensation product of cyanuric chloride,1-phenyl-3-methyl-5-pyrazolone and 3-(N,N-diethyl)amino aniline as coupling component,and 3-aminopropylmethoxydimethylsilane,3-aminopropylmethyldimet-hoxysilane,and 3-aminopropyltrimethoxysilane as silicone reactive agents.These dyes were characterized by UV-Vis,FT-IR,1H NMR,13C NMR,and MS.A method for predicting the solubility of silicon-containing dyes was established.The solubility characteristics of these dyes were analyzed and the rules were summarized.The kinds of solvents for silicon-containing dyes were obtained,which laid the foundation for the industrial application of silicon-containing dyes.For obtaining solubility of dyes in the pure and mixed solvents,this paper built a thermodynamically consistent model to correlate and predict dyes solubility in pure and mixed solvent systems based on a small initial set of measured solubility data.The solubility of the two dyes in different solvents was calculated with COSMO-SAC and NRTL-SAC models.Based only on molecular structure of the dye molecules,COSMO-SAC was able to qualitatively predict solubility,and NRTL-SAC was capable of providing accurate correlation and prediction of solubility in the pure solvents.A thermodynamic model was used to predict the solubility of silicon-containing dyes in mixed solvents.The results showed that the mixed solvents were better than pure solvents for the solubility of dyes.This method has guiding significance for the synthesis of insoluble reactive disperse silicon-containing dyes and the selection of solvents.The obtained reactive disperse silicon-containing dyes were used to color silicone rubbers and the colored silicone rubbers showed bright and rich colors.The color fastness of the dyes were evaluated,the dry/wet rubbing and washing fastness of these dyes all reached 4-5 grade and the sublimation fastness was also above 4 grade,indicating outstanding performance in terms of color fastness.Their static mechanical properties remain unchanged.The dyes with siloxane group with 3 methoxyl groups have better tear strength in the coloring silicones rubbers.Considering the cost of raw materials,the price of 3-aminopropyltrimethoxysilane(raw material of DY3,DR3 and DP3)is much lower than 3-aminopropylmethoxydimethylsil-ane and 3-aminopropylmethyldimethoxysilane.In view of the above factors,reactive disperse silicon-containing dyes with siloxane group with 3 methoxyl groups will have more advantages in the industrial application of silicon-containing dyes in the future.