High Absorption Dyeing Of PA6 Microfiber/Polyurethane Composite Material

Island fiber non-woven consists of nylon-6(PA6) and low density polyethylene(LDPE) can be used to make the composites which has been made of PA6 microfiber non-woven and microporous polyurethane filling body through impregnating polyurethane slurry, wet impregnating and toluene detaching. Mainly, this composites is used to produce microfiber synthetic leather. PA6 microfiber has large specific surface area and the polyurethane filling body has a microporous structure, so there are great differences in the structure and dyeing properties of them, these lead to PA6 microfiber/PU composite material have nonuniform dyeing and poor color fastnesss. When PA6 microfiber/PU composite material dyeing, a large quantity of dyes is needed, which will generate plenty of dyeing waste water. All these dyeing problems have become an technical challenge in PA6 microfiber/polyurethane composite material dyeing field.In order to solve these technical difficulties, this thesis has effectively improved level dyeing and color fastness of PA6 microfiber/PU composite material through the synergistic effect among those various additives with nonionic surfactant(YDA) as levelling agent, weakly cationic surfactant(MDA) as darkening agent, anionic surfactant(TDA) as penetrating agent, multi-metal acetate(SLA) as fixing agent. The dye uptake was up to 95%, that had achieved the goal of PA6 microfiber/PU composite material high absorption dyeing.This thesis has studied the microstructure and dyeing properties of PA6 microfiber non-woven component and microporous PU filling body component, which separately obtained from PA6 microfiber/PU composite material through DMF stripping and formic acid stripping method. The results show that PA6 microfiber non-woven is three-dimensional structure and PU filling body is linkaged microporous. The dyeing depth and color fastness of PA6 microfiber non-woven significantly higher than the microporous PU filling body dyeing under the same conditions, which are the main reason to leading the uneven dyeing and poor color fastnesss of composite material.This thesis has studied the dyeing conditions and optimized the dyeing auxiliaries’ amount and ratio of PA6 microfiber/polyurethane composite material with YDA, MDA, TDA as dyeing auxiliaries through the water bath asynchronous staining method which dyes penetrate firstly and then fixed. The results show that the optimal proportion and conditions of dyeing were that the content of levelling agent YDA was 1.0%, darkening agent MDA was 1.5%, penetrating agent was 0.5%, acetic acid was 1%, the amount of dye was 3%~5%, liquid ratio was 1:15, dyebath temperature was 95 ℃, the levelling time was 60 min, the fixation time was 30 min.This thesis has discussed the fixation effect respectively of multi-metal acetate(SLA), polyquaternium compounds(DUR), blocked cationic aqueous polyurethane(ZH), the aromatic polymer compound of sulfonic acid group(OD) through the water-bath asynchronous staining method. The results show that fixing agent SLA could fix dyes on PA6 microfiber/PU composite material mainly through hydrogen bonding, coordination reaction and precipitation effect. After fixing, the microfiber synthetic leather had lustrous color. When fixing agent SLA amount was 0.4%(owf), fixing temperature was 80℃, fixing time was 40 min, the wet rub fastnesses of composite material would reach to grade 3.5 and the dry rub fastness would reach to grade 4.5, which would meet the dyeing requirements of composite material products.This thesis has discussed the water-bath asynchronous dyeing mechanism through the water bath asynchronous staining method. Rate of dyeing rate curve showed that the dyes penetrated fully at high p H and were being fixed fully at low p H, the dyes did not exist competitive phenomenon on the two components, and the dyed composite material appeared better uniformity and permeability, and the dye-uptake was up to 95%. Adsorption isotherms of dyes showed that dyes’ take-up presented Langmuir-Nernst binary sorption model, when the amount of dyes was less than 5%, the dyes exhibited excellent build up property and color rendering property. The TGA and mechanical property test showed that after the dyeing, the mechanical property and thermal s Table ility of composite material had not obvious variation, which made composite material industrial production possible.In conclusion, the results of this thesis have provided a new dyeing solution and theoretical basis for PA6 microfiber/polyurethane composite material dyeing and solved the key issue for nonuniform dyeing and poor color fastnesss and dyeing pollution.