Properties, Dyeing & Finishing Of Islands-in-Sea Superfine Fiber Substrate Of Synthetic Leather

The detaching process of Polyurethane (PU) superfine fiber substrate of synthetic leather was studied in this paper. Some properties of PU superfine fiber substrate of synthetic leather were detected. PU superfine fiber substrate of synthetic leather can be accessible to disperse, acid and neutral dyes. Some new dyeing methods of PU superfine fiber substrate of synthetic leather were researched. The kinetic and thermodynamic properties of superfine fiber substrate of synthetic leather were investigated by measuring the adsorption isotherm, the rate of dye uptake, the time of half dyeing and amount of equilibrium adsorption. Some new auxiliary agents and technics were studied to improve the dyeability and fastness of PU superfine fiber substrate of synthetic leather.PU superfine fiber substrate of synthetic leather was detached with chemical treatment. NaOH and ethylenediamine play important roles in detaching process. The weight loss ratio and detaching ratio were researched under different concentration of alkali and ethylenediamine, bath ratio, processing time and temperature. Some properties of PU superfine fiber substrate of synthetic leather concerning comfortability such as stiffness, water vapor permeability, gas permeability were investigated. The results show that the weight loss ratio and detaching ratio increase with the rising of alkali and ethylenediamine concentration, bath ratio, processing time and temperature. Detaching treatment causes the increase of surface roughness and the specific surface area of the samples. With the rising of the detaching ratio, stiffness, gas and water vapor permeability increase gradually. But warp breaking strength and tearing strength decrease firstly and then increase slightly. Latitudinal breaking strength always increases with the rising of the detaching ratio.The disperse dyeing of PU superfine fiber substrate of synthetic leather in the presence of methyl methacrylate (MMA) was investigated in this paper. The incorporation of a low concentration methyl methacrylate monomer to disperse dyeing bath was found to be very useful in improving dyeability. The dye uptake and color strength were improved significantly by incorporating MMA in the dyeing bath. The influence of MMA on dyeing is explained to have two aspects: (a) MMA can entrap the disperse dye in its micelle and form a concentrated dye layer on the superfine fibre surfaces. The dye layer facilitates diffusion and fixation of the dye molecules on superfine fibres. (b) MMA acts as a dye carrier for the polyamide superfine fibre during dyeing. It loosens the molecular structure of the superfine fibre and facilitates the entry of dyestuff molecules. Partition coefficient (K) of disperse dye decreases with the rising of temperature, but always more than 1. The adsorption isotherms for PU superfine fiber substrate of synthetic leather with disperse dye present Langmuir-Nernst sorption model. Disperse dye exhibits excellent build up and deep dyeing for PU superfine fiber substrate of synthetic leather.PU superfine fiber substrate of synthetic leather was dyed with acid dyes in the presence and absence of double-chain surfactant. The dyeing properties of the sample were studied by measuring the adsorption isotherm, the rate of dye uptake, the time of half dyeing and amount of equilibrium adsorption. The surfactant having aliphatic double chains aggregates themselves in aqueous solution to form bilayer structures. It seems to have affinity to both acid dye and PU superfine fiber substrate of synthetic leather. The ultimate consequence of the function is to facilitate diffusion into and absorption of the dye molecules on the samples. The kinetic results show the dyeing samples in the presence of double-chain surfactant have a higher equilibrium dye uptake compared to that in the absence of the surfactant. The thermodynamic analysis shows that the adsorption isotherms for PU superfine fiber substrate of synthetic leather with acid dye present Langmuir sorption model. Partition coefficient (K) of acid dye changes largely with the variety of temperature, but always more than 1. The deep dyeing and build up of acid dye for PU superfine fiber substrate of synthetic leather is good. The washing fastness and rubbing fastness of acid dye in the presence of double-chain surfactant lower than in its absence.PU superfine fiber substrate of synthetic leather was dyed with neutral dyes in the presence and absence of benzoic alcohol. Dyeing kinetics and thermodynamic of the samples were investigated. The results indicate that the dye uptake and color strength in the presence of benzoic alcohol are substantially higher than in its absence. Benzoic alcohol acts in two ways: First, it dissolves large amounts of neutral dye and is considerably adsorbed on the fibers. The concentrated dye layer on the sample surfaces plays an important role in improving dyeing rate and dye exhaustion. Second, it interacts with the fiber, breaks the intermolecular bonds, and reduces the glass transition temperature. Due to the solvent function, the diffusion and absorption of the dye molecules are enhanced. Partition coefficient (K) of neutral dye is different drastically with the change of temperature, but always more than 1. The level-dyeing property of PU superfine fiber substrate of synthetic leather with neutral dye is not very good. The adsorption isotherms for PU superfine fiber substrate of synthetic leather with neutral dye present Langmuir sorption model. The deep dyeing and build up of neutral dye for PU superfine fiber substrate of synthetic leather is excellent. Benzoic alcohol has no effect on washing fastness and rubbing fastness of PU superfine fiber substrate of synthetic leather.Two techniques concerning deep dyeing of PU superfine fiber substrate of synthetic leather were presented. One is mixing thulium deepening agent ZSJ-1 into dye bath to increase dye depth. The other is to reduce surface refractive index by finishing with organosilicon resin NTF-3. The remarkable deepening effect was shown when PU superfine fiber substrate of synthetic leather treated with thulium deepening agent. The deepening effect of thulium deepening agent for acid and neutral dyes is better than for disperse dye. The deepening function of thulium mainly comes from mordanting action. Thulium acts as a bridge during the dyeing process. The dye molecules and fiber molecules are linked together through thulium, which enhance the dye depth and fastness. A uniform film is formed on the surface of PU superfine fiber substrate of synthetic leather after treated with organosilicon resin, which reduces the refractive index of the samples. It is obvious that the organosilicon resin can deepen the dyed samples. The K/S andΔE can be enhanced after resin finishing. The organosilicon resin has an unfavorable effect on gas permeability and moisture penetrability. PU superfine fiber substrate of synthetic leather has a soft and smooth handle after resin finishing.Two processes concerning fixation of PU superfine fiber substrate of synthetic leather were investigated, which included using cation fixing agent and sol-gel treatment. The experimental data showed that the wetting fastnesses of acid and neutral dyes were enhanced after cation fixing agent treatment. Cation fixing agent can dissociate to organic cations in the solution. These organic cations integrated with dye negative ions and formed undissolvable sediment in the fibers. Thus, the samples dyed with acid and neutral dyes got good color fastness. The results also showed that the sol-gel treatment has a function on fixation. A thin oxide film can be formed on the surface of PU superfine fiber substrate of synthetic leather after sol-gel treatment. The dye molecules are thus anchored on the samples, which enhance the color fastness to some extents. The washing fastness and rubbing fastness of PU superfine fiber substrate of synthetic leather can be improved half grade or so. Breaking strength and tearing strength decrease greatly and gas permeability and moisture penetrability decrease slightly after sol-gel treatment. The handle of the treated substrate changes bad.