Study On The Nano-pigment Dope Dyeing Of Polylactic Acid Fiber

Polylactic acid(PLA)fibers are excellent biodegradable fibers with physical properties close to those of polyester(PET)fibers,and have excellent biodegradable properties that can be completely degraded by the natural environment.Moreover,PLA fibers can be produced from plants and crops such as corn,wheat or even straw,which is natural,environmentally friendly,and from a wide range of sources.PLA fiber is an eco-friendly synthetic fiber with excellent potential to replace polyester fibers in some applications.This thesis used nano-pigments to do the dope dyeing of PLA fibers.Analyzing the properties of the color masterbatch and PLA-colored filaments was studied.The application performance of PLA nano-pigment dyed filament colored fabric was explored by weaving PLA colored filament into a woven fabric in further.Finally,a color development experiment was carried out.Complementing the two colors of purple & green and the combination of purple & orange mixed with a variety of nano-pigments,which completes the chromatographic integrity of the coloring of the PLA stock solution.The specific research content and results are as follows:First,the nano-pigment is dispersed and prepared into masterbatch by two dispersion processes,and the dispersion effect of the pigment and the performance of the masterbatch are analyzed.The results show that the minimum particle size of the pigment in the ultra-dispersed color masterbatch is in the order of hundreds of nanometers,and in the ordinary dispersion masterbatch of only 1-5 microns.Using ultra-dispersing agents to disperse the nano pigments,the particle size of the pigment is smaller and the dispersion is more uniform.The dispersion effect of the pigment will affect the performance of the masterbatch.The super-dispersed masterbatch has a larger MFR,a smaller FPV,good dispersibility and fluidity,which has little effect on the spinning process.Then,using the masterbatch to do the dope dyeing,in which 860D/120 F PLA colored yarn with a pigment content of 1% was prepared,and the tensile properties and coloring effects of the colored yarn were characterized.The results showed that the ultra-dispersed colored yarn has better tensile properties and coloring quality.When the strength loss is about 1%,the elongation loss is about 3%,which is much smaller than the 8% and 10% of the ordinary dispersed colored yarn;The color difference of the super-dispersed colored yarn is 0.2,the heat-resistant migration level is above grade 4,the coloring uniformity and stability are very good,which can satisfy the requirements of production and processing.The heat-resistant migration grade of the ordinary dispersed colored filament is below grade 4,which does not meet the requirements.Next,in order to study the effect of PLA dope dyeing in further,PLA colored filaments were made into a woven fabric.Analyzed its tensile properties,dyeing effect and color fastness,and compared with two PLA fabrics dyed by high temperature & high pressure and carrier dyeing process.The results showed that the K/S values of 1%(o.w.f)red,yellow,and blue super-dispersed colored fabrics were 16,20,and 22.The optimal color depth that is slightly worse than 2%(o.w.f)of the high temperature and high pressure dyeing PLA fabric,the breaking strength and elongation loss were only 3% and 4%,the color fastness was above grade 4,and the comprehensive effect was the best.And the pigment content was only 1%(o.w.f),there was a lot of room for coloring depth.However,the tensile properties and coloring effects of ordinary disperse colored fabrics were very poor,with the worst overall performance.Finally,the nano-pigments were used to conduct the dope dyeing test for the two inter-colored of purple & green and two mixed colors of orange & purple.The tensile properties,coloring effect and color fastness of the prepared purple and green super-dispersed colored filament were close to the three primary colors.The indicators of purple red and orange would be slightly worse because of the mutual influence of various pigments when the original liquid was colored.It could also satisfy the requirements of production and processing,and had a good coloring effect.Therefore,PLA can expand the chromatographic system of the coloring of the original liquid by mixing colors with nano pigments.