Study On Improvement Of Wet Rubbing Fastness Of Dark Bio-polishing Knitted Fabrics

Wet rubbing fastness is an important quality index for dark dyed cotton fabrics, which is alsoa technical difficulty of the dyeing and finishing process. Systematic control measures should beadopted from the gray fabric quality, dye selection, dyeing and finishing process, so as to improvethe fixation rate of the dye and fiber, and minimize the dye quantity adsorbed on the fiber byphysical adsorption status. Based on theoretical factors affecting the fastness to wet rubbingfastness, this paper is to sort out and analyze the dyeing and finishing process of bio-polishingfabrics, make it clear about the causes for low web rubbing fastness, and explore specificmeasures to enhance the wet rubbing fastness. In this way, it is expected to make fabrics soft andmeet certain requirements, while improving the fastness to wet rubbing by1.5-2level.It is determined by study that main factors affecting the fastness to web rubbing fastness inthe original process are as follows:(1) Black knitted fabrics of cotton and polyurethane dyeingrequires multiple dyes for combination dyeing as well as high dye concentration. Dyeing craft canhave significant influence on the fabric bursting strength with much flooding. But it is inconsistentwith the actual benefit to replace the dye and dyeing craft.(2) The subsequent dye-fixing agentcan dramatically improve the wet rubbing fastness of fabrics, but the softening agent can affect theprocessing effect of the dye-fixing agent and reduce the wet rubbing fastness. So the wet rubbingfastness of black knitted fabrics of cotton and polyurethane will be improved by adjusting thesubsequent craft and auxiliaries.Through the selection of the waterborne polyurethane wet rubbing improving agent, thewaterborne polyurethane wet rubbing improving agent806is determined to be the dye-fixingagent, and its fixation mechanism is identified via the infrared test and the electron microscopescanning, that is, membrane coverage mechanism, salt-forming mechanism, and absorbingcross-linking fixation mechanism. After the optimization of the single factor and orthogonal test,the fixation treatment craft of the black bio-polishing black knitted fabrics of cotton and polyurethane is: concentration of the dye-fixing agent is8%(o.w.f),30min treatment at30℃isconducted, and then for5min drying at100℃and60s baking at160℃. Compared to traditionalcrafts, the treatment temperature of the new craft has reduced from45℃to30℃, and the webrubbing fastness of the fabric has been improved from level1-2to level4, but the fabric lackspositive hand feeling, which is hard and unsmooth.Using the new block amino silicon oil8992as the softening agent. The infrared spectrum testis carried out for structural characterization of the softening agent, the result of which indicatesthat the new block amino silicon oil8992applied is a copolymer of siloxane, polyamine andpolyether ternary block. When there is a small amount of dosage, the satisfactory hand feeling canbe achieved. The exploration about the impact of softening agent concentration on the burstingstrength, creasy recovery angle, draping and crock-fastness has suggested that the burstingstrength and crock-fastness of black cotton polyurethane feeding hair cloth will reduce constantlywith the increase of softening agent concentration, and that the creasy recovery angel and drapingwill be improved continuously, which indicates that the softness and hand feeling of fabrics aftertreatment have been improved significantly. The dye-fixing and softening craft of blackbio-polishing knitted fabrics of cotton and polyurethane after optimization is: concentration of thedye-fixing agent is8%(o.w.f), and concentration of the softening agent is1%(o.w.f),30mintreatment at30℃is conducted, and then for5min drying at100℃and60s baking at160℃.Compared to traditional crafts, the web rubbing fastness of the fabric after new craft processinghas enhanced from level1-2to level3-4, and its hand feeling is soft, plump and smooth, whichcan meet certain requirements.The impact of the treated new craft on the performance of the black bio-polishing knittedfabrics of cotton and polyurethane is shown below: The color tone of the dyed fabrics has nodistinct change, but the bursting strength has been reduced significantly. The cotton polyurethanefeeding hair knitted fabric after treatment has certain water-washing resistance and soap-washingresistance properties. After washed by water for20times or by soap for10times, the fastness towet rubbing of the fabrics can reduce from level3-4to level3.