Study On Dyeing Of Ultra High Molecular Weight Polythylene Fibers

Disperse dyes with high planarity and super hydrophobic structure were studied to dye ultra high molecular weight polyethylene（UHMWPE）fiber and its wet gel spinning extraction fiber which have extreme hydrophobicity and high level of crystallinity.The dyeing property of UHMWPE finished fiber was discussed by evaluation of the color strength（K/S）,fastness,mechanical properties and so on.The dyeing processes of UHMWPE finished fiber were discussed by carrier dyeing method,high temperature and high pressure dyeing method and temperature-gradient dyeing method.Firstly,the dyes,carriers and dispersing agents were selected,the results showed that methyl yellow,Sudan disperse dyes and dispersant AEO-9 were effective and could be used in the following specific dyeing processes.And the carrier effect was not obvious,for the UHMWPE fiber which have extreme hydrophobicity and high level of crystallinity.Dyeing properties of the UHMWPE finished fiber with high temperature and high pressure dyeing method were discussed.Through single factor experiment and L9（3⁴）orthogonal test,the influences of different factors,such as dyeing temperature,dyeing time,the dispersant and pH value of dyeing bath,were discussed.The optimization process was achieved at the concentration of dye 5%o.w.f.,the concentration of dispersant 0.3%,130℃for 60 min,pH=5.The K/S value of dyed fiber reached 12.82 and the color fastness was higher than rating 3,which was in accordance with industry requirements,but the strength drop rate of dyed fiber was about14.5%.In order to reduce the damage to the strength of fiber by the high temperature,the temperature-gradient dyeing method was explored.The results showed that under the conditions of dyeing at 85℃for 30min,high temperature at 125℃for 25min and the concentration of dispersant 0.2%,the K/S value of the colored fiber was 11.79,the color fastness were more than3,and the fiber strength drop rate was decreased obviously to 3.4%.Dyeing properties of extraction UHMWPE by wet frozen spinning were studied with single factor experiment and orthogonal test.When the dye was 5%o.w.f.,the concentration of dispersant was 0.3%,dyeing temperature was 100℃for 20 min,pH=7,the optimization dyeing process was determined and the fastness of dyed extraction fiber were more than 3.The extraction yarns were dyed under optimum conditions,and the maximum draw ratio of the three stages was 2.4 times.The kinetic data were investigated based on the methyl yellow and oil red O.The results show that the equilibrium adsorption capacity of oil red O is much more than that of methyl yellow dye,but the diffusion of methyl yellow dye in UHMWPE fibers is better than that of oil red O dye.The thermodynamic study of methyl yellow dye showed that the isotherm of methyl yellow dye was Nernst type adsorption.The standard affinity of methyl yellow dye at 130℃is about-5.39 kJ·mol^-1.