Study On Forming And Properties Of CPC Spunlaced Composite Nonwoven Materials

Spunlaced composite technology can be used to prepare new materials with high performance and multiple functions through hydroentangling of several layers.Pulp fiber,a kind of natural biodegradable cellulose fiber, is regarded as perfect green material with an extensive source and a lower cost.In this study,green fiber combined with new nonwoven technology were used to develop the CPC spunlaced composite material.The results demonstrated that CPC spunlaced composite material can meet the performance requirements of fabric and solve raw material sourcing problem of one-off products.The mechanism of pulp paper fluffing and entanglement with synthetic fiber by squirt impact were studied through analyzing CPC web-forming and consolidating technology,as well as understanding the properties of raw materials thoroughly.The optimum processing parameters configuration and technical problems were also investigated.Moreover, the properties of mechanism,the performance of absorbency and the capability of permeation were tested,respectively.Pulp wrinkled tissue has suitable tensile strength,high absorbent capability,flat and strip shaped cross section,and low moment of inertia, so it is easy to be fluffed and entangled with polyester and viscose fiber under squirt impact so that pulp fiber is valued as the most suitable for hydroentangling.The experiment was carried out by single regulator method,and all process schemata were evaluated by Borda excess method.The results revealed that polyester is superior to viscose fiber for spunlacing,and it is best to control pulp paper content between 20%and 30%on the way of low pressure,impacting several more times, alternating impacted surfaces every twice for processing.What's more, tension controlling setting is needed to meet the requirements of unwinding and synchronization during process,so as pre-wetting procedure to CPC forming,which should be spent a period of more than 0.5 seconds between pre-wetting injector and the first one.And sleeve is better than mesh grid for CPC forming.On the basis of mastering spunlaced principle thoroughly,when the impacting pressure equals to 100 bar,the speed of water jet is calculated as 135.77m/s,squirt impact is only 0.215N,and energy coefficient is 9.6×10~4,as a result,the impact of hydroentangling is very flexible to web that can hardly damage fiber.With the increase of energy,Bonding Index (BI) and Utilizing Coefficient of fiber strength(QLV) level up and then down,which have a high linear regression.Theoretically,pulp paper's fluffing process under water jetting can be described as five steps:contact on the surface;additive chemical dissolution;fiber swelling;further swelling and paper fluffing.In the pulping,Congestion Factor is 42.46 which is less than 60,so pulp fiber can only move limitedly as continuous reticulation structure,but its rotating is very easy to realize which has the highest degree of freedom. Hydrogen bond is the primary way for pulp fiber to be combined with synthetic fiber,and bonding and fencing also exist besides mutually entangling,furthermore,pulp fiber can be seen on the surface of CPC.The handle of CPC is more fluffy than normal spunlaced materials without pulp paper inside,and capillary,wicking capability,as well as water retention have also been improved.The tensile strength of CPC mainly depends on synthetic fiber rather than pulp paper,but MD/CD ratio can be reduced a lot with pulp paper.In addition,the stages of tensile fracture can be considered as follows:stretch and slippage of synthetic fiber;fracture of synthetic fiber and failure of pulp fiber.