Easy-Care Finishing For High Level Of Cotton Fabrics

Wrinkle resistant finishing of cotton fabrics as an important step infinish processes, has been paid great attention for a long time, however,wrinkle resistant for higher DP rating has been a hard task since thetechnology of wrinkle resistant finishing came into existence. In this paper,ultra low formaldehyde finishing agent of SDP1 and non-formaldehydefinishing agent of butaneteracarboxylic acid （BTCA） were used ascross-linking agents to finish cotton fabrics, respectively, and the finishingeffects of agents, catalysts, additives, and processes on cotton fabrics werestudied.Two different catalysts for SDP1 were used in the treatingformulation, one is the traditional MgCl₂·6H₂O/CA and the other is LFC.The proper concentration of the two catalysts was determined bycomparing the wrinkle recovery angle （WRA）, strength retention andwhiteness of finished fabrics, and the effects of different catalysts werecompared. The results reveal that the two catalysts have differentadvantages, finished fabrics using LFC as catalyst have higher strengthretention, while those using MgCl₂·6H₂O/CA have good whiteness.The effects of water soluble polyurethane and softening agents on fabric performances were studied. Single factor and compoundingexperiments were carried out to determine the effects of factors such as theconcentration of finishing agent and water soluble polyurethane, as well asthe types and amounts of softening agents. And an orthogonal design wasintroduced on that basis to decide the preferred treating formulation. Theresults indicate that the treatment using SDP1 combined with polyurethaneand softeners is more effective in wrinkle resistant finishing of cottonfabrics. Softeners would improve the WRA and impart a pleasing handle totreated fabrics. Water soluble polyurethane would form a thin elastic filmon the surface of fabrics and improve the WRA without adverse influenceon strength retention of fabrics. The cotton fabric finished with thepreferred formulation features a DP rating of 4.0, breaking strengthretention of 40.6%, tearing strength retention of 65.2%, and theformaldehyde release less than 75mg/kg.In order to improve the strength retention of treated fabrics, the effectsof some additives were explored. The proper dosages of these additiveswere determined by examining the fabric performances. The resultsrevealed that some additives such as sodium chloride, methanol, urea andammonia improved the strength retention of treated fabrics to differentdegrees. Among the additives, ammonia and urea are the more effectivestrength protectants, and both of them can improve the strength retentionfrom 41% to more than 51%, while WRA only slightly decreases. Methanol can also improve the strength effectively and the treated fabricshave fairly good whiteness.A comparison of padding process and impregnating process wasmade with SDP1 as the cross-linking agent. The results showed that withthe same formulation the impregnated fabrics have slightly higher WRA,strength retention and breaking elongation. This could possibly due to thehigher fiber accessibility and uniformity of crosslinking in theimpregnating process.The application of non-formaldehyde agent of BTCA on cottonfabrics was also carried out. The DP rating of BTCA-treated fabrics isnearly 4.0. With the similar WRA or DP rating, the BTCA-treated fabricexhibits higher strength retention than that of SDP1-treated.