Abstract: Polyester fabrics are usually dyed with disperse dyes. However, the affinity between disperse dyes and polyester are weak interactions, such as van der Waals force and hydrogen bond. During the finishing process, thermal migration of dyed polyester fabrics may occur if high temperature is used. In such case, the dye molecule will migrate from the inside to the surface of the fiber, resulting in unlevelness and poor color fastness. The use of dyes with a planar molecular structure can enhance the force between the dye and the fiber and effectively alleviate the heat migration phenomenon. Indophenine is composed of quinoidal bithiophene structure that end-capped with two indole-2-one groups. The molecular π-conjugation system of indophenine presents planar characteristic. In addition, indophenine is usually synthesized by indophenine reaction, which is easy to operate and has high product yield. Previously, our group discussed the dyeing properties of hydrophobic indophenine dyes on polyester fibers. The results showed that the dye-fiber interaction force between indophenine dye molecules and polyester fiber is very strong. However, due to the existence of strong intermolecular force which hinders the formation of single-molecule-state dyes, the dye exhaustion of indophenine dyes on polyester fabrics is not high enough.
In this paper, three blue dyes D1―D3 were synthesized through indophenine reaction. The structures of dyes D1―D3 were characterized by mass and infrared spectra. The lattice parameters and HOMO/LUMO energy level information of dyes D1―D3 were calculated. The thermal stability, acid and alkali stability and absorption characteristics in DMF of dyes were tested and analyzed. Polyester fabrics were dyed with dyes D1―D3 by high-temperature and high-pressure dyeing method. The dyeing process was optimized, and the dye uptakes, color depths, color fastnesses and migration values of the dyed fabrics were tested. The results showed that the optimized dyeing condition should be at pH of 5~6, dyeing temperature of 130 ℃ and dyeing bath ratio of 1∶50. Under the optimum dyeing condition, the dye uptakes are 84.8% (D1), 97.5% (D2) and 85.2% (D3) and the K/S values of dyed polyester fabrics are 17.1 (D1), 8.1 (D2) and 16.3 (D3). The fabrics dyed with dyes D1―D3 have excellent thermal migration resistance, and the migration values are less than 10%, which are obviously better than that of the conventional disperse dye C.I. disperse blue 56. In addition, the color fastnesses to soaping, rubbing and sublimation of polyester fabrics dyed with dyes D1―D3 are excellent, all of which are above 4~5. The introduction of methoxy or methyl groups on the thiophene unit can effectively tune the intermolecular forces between the dye molecules, promote the formation of single-molecule-state dyes in the dye bath, and thus improve the dyeing performance of the indophenine dyes.

Key words: indophenine, steric group, dyeing properties, polyester, heat migration

摘要： 为探究噻吩单元取代基对靛吩咛型分散染料染色性能的影响，采用靛吩咛反应合成3支蓝色染料D1―D3，通过高温高压染色法对涤纶织物进行染色，并测试了染色织物的上染率、色深和色牢度。结果表明：染料D1―D3的合成收率为61%~85%，在二氯甲烷中的最大吸收波长位于635~649 nm，摩尔消光系数为16500~39300 L/(mol·cm)，且具有较好的热稳定性与耐酸碱稳定性。染色优化工艺参数为：染色温度130 ℃、浴比1∶40、染浴pH值5~6。在优化染色工艺条件下，染料D1―D3的上染率分别为84.8%、97.5%和93.3%，染色织物K/S值分别为17、8和16，耐摩擦、耐皂洗和耐升华色牢度均在4级以上；染色织物还具有很好的耐迁移性，染料迁移率均在10%以下。噻吩单元引入取代基对于调节靛吩咛染料分子间作用力、提升上染率具有显著的促进作用。

关键词: 靛吩咛, 位阻基团, 染色性能, 涤纶, 热迁移