Spun-Lace Process Of Leather Waste Collagen Fiber And Application Properties Of The Product

Leather waste collagen fibers are obtained after mechanical separation of leather scrap. This kind of fiber has large discreteness of fineness and length. It also has a high specific surface area and the tendency of fibrillation, leading to inter-fiber flocculation into the group easily and poor separation. According to these features, this paper conducted researches including the uniformity of webbing, spun-lace technology, the mechanism of fiber entanglement and the products'application performances. Through these studies we can get a good uniformity of the web and appropriate spun-lace process conditions, we can also understand the entanglement mechanism and performances of the products for different applications. Thus we can provide full and accurate experimental data for leather waste collagen fibers in spun-lace processing.Due to the poor separation of waste leather collagen fibers, the good uniformity of the fiber web is hard to be obtained. To solve this problem, the fiber surface treatment, carded and air-laid pilot test were taken. The aim was to find a suitable webbing process and get better uniformity of the web.The results of webbing experiment show that when 80% of raw material content is collagen fiber, the web can not be formed through carding process. While in the same condition, the air-laid process is feasible. Twice pre-loosening can improve the uniformity of network in the air-laid process. The reasonable air-laid process parameters are as follows, the input speed of network is 92, the output speed of network is 100 (the two values are DC electrical resistance).In this paper, we carried out systematic studies of spun-lace process. The spun-lace pressure, the transmission belt speed and the number of spun-lace times were chosen as three important factors for the parameters, while tensile breaking strength, average pore size and entanglement coefficients were being as the characterization of the products. Firstly the single-factor tests were taken to study the performance variation of the products when each parameter changed. Then a orthogonal experiment was taken to find the optimal process parameters.Spun-lace processing test shows that the spun-lace pressure, the transmission belt speed and the number of spun-lace times all impact on the products' performances. And the impacts also have a certain degree of regularity. As the parameters change, there is respective critical state in tensile breaking strength, average pore size and entanglement coefficients. Through the orthogonal experiment and a comprehensive analysis, the optimal spun-lace process is concluded as follows, the spun-lace pressure is 155bar, the transmission belt speed is 6m/min and the number of spun-lace times is 4.In this article we also observed the internal structure of the product by scanning electron microscopy and three-dimensional imaging, to analyze its entanglement mechanism. Then through analysis of different entanglement coefficients products, we aimed to find the law of entanglement under the influence of spun-lace parameters changing. This also provides a structural basis for changes in product performance.By observing the internal structure of the products, we conclude that the entanglement mainly consists of three parts, which include mutual entanglement of polyester fibers, the adhesion between collagenous fibril and polyester and the entanglement between the collagenous fibril. With the tangles coefficient changing, the structure of the products changes in a certain law. The higher the tangles coefficient of the sample is, the better degree polyester fibers interspersing in the thickness direction has, and the larger tensile breaking strength the sample has. The greater opening degree collagen fibers have, the smaller average pore size will be. When the sample surface holes increased, the flatness of the surface decreased.Finally, the heavy metal adsorption, sound-absorbing and leather fabric test were taken into account to show the application performances of the product. According to this, we then found the different spun-lace parameters'influence on the product's application performances, which provided a reliable experimental basis to the practical application of the product.The results showed that the product has a good heavy metal absorption and sound-absorbing effect. The Cu2+ adsorption of the product increased with the increase of collagen content. With spun-lace pressure changing, significant changes happen in its adsorption capacity. When the transmission belt speed increased, the sample's Cu2+ adsorption also increased. When spun-lace process changed to improve the uniformity of the product structure, it could improve the sound absorption coefficient. As the thickness increased, the acoustic performance gradually improved. Tear strength and dry shrinkage rate in line with requirements of leather fabric, with a good prospect. And its tear strength and dry shrinkage rate were both in line with requirements of synthetic leather fabric. Therefore, the collagen fiber spun-lace fabric has good prospects.