Synthesis Of Organic Pigments With Good Light Fastness

Hindered amine as light stabilizer is applied wildly in polymer , which is the most active polymeric additive field in the last 30 years . Hindered amine can trap the radicals that polymers generate during degradation, but can not absorb ultra-violate rays. This ensures that the desirable polymer properties can be maintained throughout the entire service life. 4-hydroxylpiperidine and 4-aminopiperidine are two important intermediate of hindered amine. Millions of kinds of hindered amine are derivatives of the two ones.In all kinds of hindered amine on sale, the amount of esters of 4-hydroxylpiperidine counts a large scales. The synthetic methods of ester include acyl chloride reaction, carboxylic acid reaction, and inter-esterification reaction. Inter-esterification reaction of 4-hydroxylpiperidine has been found in the American Patents. In this paper 4-hydroxylpiperidine is used to exchange with 3-substituted or 4-subsitituted bezoate, and two intermediate are obtained. Reaction conditions, such as the mole ratio of piperidin-4-ol to benzoate, the amount of catalysis, reaction time, have been optimized by level experiments. The objective compounds are characterized by TLC , IR data and elemental analyses.Pigments are used broadly as colorant for printing ink, dope and plastics. The yield of printing ink, or dope and plastics exceeds one hundred of million tons, most of which are coloring polymer. Organic pigments have become the hotspot in view of its vivid luster, strength tint, and wild chromatogram. But poor light stability and low mobile are two common drawbacks for most kinds of organic pigments. It is a difficult task to research a kind of pigment with good light stability, and this task needs to be finished immediately.To date, pigments and stabilizers are melt with polymer during theprocess. The molecular weight of pigments or stabilizers is low, resulting in the poor light stability and low migration. Usually improving the molecular weights of pigments and stabilizer can solve this problem. But that will increase the cost and the efficiency of easy mixture is very low.In this paper, a new kind of organic pigment with hindered amine structure is synthesized. These new organic pigments integrate with hindered amine by chemical bonds, so that the light fastness of pigments are increased, what's more, the heat-resistance fastness and migration are improved because of the higher molecular weight.Eleven organic pigments are synthesized, eight of which are novel pigments with hindered amine structure. Another three are old kinds, which act as collators. All pigments are characterized by TLC , IR data and elemental analyses.The hindered amine structure has effect on the photo-oxidation of pigments. In this paper, the light stability and photo-degradation mechanism of the eleven synthetic pigments are discussed.Sun Deshuai (Textile chemistry and dying and finishing Specialty)Directed by Professor Zhang Xiaodong...