Stability of lac pigment

The stability of lac pigment under different conditions such as temperature,pH value,metal ions,oxidants and reducing agents was investigated by spectrophotometric methods for the purpose of providing a theoretical basis for its utilization in dyeing of textiles.The results showed that the lac pigment color changed with the pH value of solution;and temperature had little influence on it in acidic condition;oxidant,reducing agent,and alkali were disadvantageous to its stability;Ca~(2+)、Cu~(2+)、Al~(3+)、 Fe~(3+)、Fe~(2+)、Zn~(2+)、Sn~(2+)could complex with lac pigment,alter the color of pigment solution;lac-Fe~(2+)complex was confirmed by infrared absorption spectrum.