Research Of The Wood Pulp Fiber Loss Phenomenon In Different Consolidated Structures Of Fiber Web During The Hydroentangled Composite Process

Wood pulp fiber hydro-entangled nonwoven material has high tensile strength, and it is breathable and soft, with good draping, moisture absorption and low price, so it is a kind of high value-added products, extending a broad market prospects in the healthcare field as wipes. But in the process of hydro-entanglement, wood pulp fiber is extremely short so it is easy to lose, and enter the water filtration system. It not only creates difficulty for water filtration system, but also creates fiber waste, and increases cost. Researches of the influence factors of wood pulp fibers loss in the process of hydro-entanglement is inadequate and fiber loss mechanism is almost blank.Based on the analysis of the various properties of different nonwoven base web, the suitable nonwoven base webs are selected to be reinforced with wood pulp fibers by hydro-entanglement as samples. Mainly the influence of the types of base webs, wood pulp content, hydro-entangled parameters on sample performances is discussed, and the wood pulp fiber loss mechanism is preliminary explored. Conclusions are basically obtained as follows:(1) Wood pulp fibers and fibers in the nonwoven base webs are entangled by hydro-entanglement. Under the water drive, wood pulp fibers penetrate into the nonwoven base webs internal space, and entangle fibers in the webs; Nonwoven webs works as skeleton to support, entangle the wood pulp fibers. In addition, the wood pulp fiber is flexible to move, movement of fibers in base webs is relatively not obvious; The distribution of wood pulp fiber in the material opposite is less than the positive.(2) Optimal composition of wood pulp fiber and hydro-entangled parameters are determined. When the PP/PE spun-bonded nonwoven base web with an area density of17g/m2is hydro-entangled with wood pulp fiber, advisable wood pulp fiber content is around65%. Hydro-entangled process parameters choice:wood pulp hydro-entangled material should be made with low pressure water; Wood pulp fiber loss increased with the increase of the water jet number, so the water jet number is suitable to be controlled within4; Wood pulp fiber loss reduce with the increase of belt speed, but fiber entanglement is not enough because the speed is too high, also high speed of belt is leading to high wood pulp fiber loss, so it is suggested the belt speed is12m/min.(3) The Nonwoven base webs have influence on the entanglement and loss of wood pulp fiber. Wood pulp fibers do not adhere to the bonding areas of the point bonded nonwoven base webs and slide, but entangle fibers of webs in the fiber areas, and the entanglement between the fibers in the webs and the wood pulp fibers is weakened as the fibers in the webs are bonded; fibers in the hot air-through bonded nonwoven base webs are bonded by small point, so fiber motion is also restricted so that entanglement between the fibers in the base web and wood pulp fibers is weakened; fibers in the hydro-entangled nonwoven base web are easier to move to help wood pulp fiber to insert, prone to grip and entangle wood pulp fibers.(4) Nonwoven base web needs to have a suitable pore size distribution for wood pulp fiber entanglement. The pore diameter of aperture in the base web is too small, wood pulp fiber is not easy to penetrate into the base web, and sliding, gathering together, unable to realize effective compound; The pore diameter of aperture in the base web becomes bigger, the worse entanglement effect of wood pulp fiber, so the loss of wood pulp fibers increases.(5) Wood pulp fiber loss has occurred in the edges and inside of the nonwoven base web. The loss mechanism of wood pulp fiber in the edge of the base web is the result of horizontal driving and splashing of the water jets, as well as flushing action of the turbulent above the surface of web; The loss mechanism of fiber wood pulp in the inside of the base web is: stability of the entanglement structure formed by wood pulp fiber and wood pulp fiber, wood pulp fiber and fibers in the web is poor, under the effect of spraying of water jets, wood pulp fiber moves, and when water energy is higher than the friction between wood pulp fiber and other fibers, wood pulp fiber loss will happen. The loss of wood pulp fiber increases with the increase of water energy.