Hemp Fiber "flash Explosion" Processing Technology

By far, all the textile's researchers and producers in China and other countries have common realized that the de-gumming is a necessary process to spin yarns and weave cloth. The traditional de-gumming ways are time-consuming, laborious, ineffective and poor quality, and some ways recently adopted such as chemical, enzymatic and chemical-enzymatic and so on don't completely resolve the de-gumming question. According to the utilization of the explosive principle and technique in the field of paper making, in this trial the raw hemp is treated with the explosive technique. That is to say, the internal water molecules of the fibers, which have absorbed high energy under the high temperature and high pressure, conduct the adiabatic expansion in the transient period of pressure release, and apply work outside meanwhile. Then the expanding gas acts on the big molecule chains of cellulose, hemi-cellulose and lignin etc. in the form of shock wave, which enables them to produce the shear force under the condition of batching. Because the deformation speed of fibers is much slow than that of shear wave, a repeat function of shear force is created, leading to disbranch and microstructure deformation of hemp fibers. In addition, the thermal function under the high temperature and high pressure probably decomposes hemi-cellulose into soluble candy, promote the softness and partly degradation of lignin, contributing to the looser linkage among fibers, which is beneficial to treat the hemp in ways of the mechanical and chemical.The research shows that the hemp fiber bundle, which are adhered together with the gum, is effectively separated. The micro-hole of single fiber's surface becomes bigger, which is beneficial to absorb easily chemical reagents, and the fiber's physical-chemical properties have apparently changed. After the explosive treated hemp is directly immersed into water and dried in oven, the weight loss rate and cellulose content obviously raise while the lignin content declines especially. With the comparison of the untreated sample, the chemical de-gumming's time obviously becomes shorter, and the residual gum content is also smaller. Under the condition of 30%(moisture content), 2.0Mpa(pressure) and134℃ (temperature), the best degummed hemp fibers can be obtained.With the combined of cotton spinning machine and wool spinning machine, the pure hemp yarns can be made in our trial. And the spinning process is: degummed hemp , opener for wool, oil, fearnaught machine, oil, woollen card, drawframe, ring-spinning frame. Through this trial, it verifies that the hemp spinning is realized easily after the explosive treatment and the spinning condition also becomes simplied, which shows that the explosive treatment is an effective method in order to better improve the hemp yarns' quality.