| 摘要 |
PURPOSE:To obtain a package having good unwinding performance in high speed longitudinal taking by using a cylindrical coreless carbon fiber having a specified apparent winding density and a specified twill angle in the innermost layer. CONSTITUTION:The winding density is within the range of 0.3-1.0g/cm<3>. With a lower density, a little vibration will cause a package to get out of shape. On the contrary, with a higher density, than 1.0g/cm<3>, it is necessary to increase tension at the time of winding, so that in case of carbon fiber (CF) having low ductility, the occurrence of yarn breakage is increased to degrade the value of a product. The twill angle theta of the innermost layer is preferably within the range of 8 deg.-25 deg.. If it is smaller than 8 deg., as the mutual overlap of CF in the package is a little, the package is liable to get out of shape in the coreless condition, and if it is larger than 25 deg., the hardness of the package is lessened, so that when a shock is given, the package is liable to get out of shape. In order to obtain a coreless package, CF is taken up under designated conditions by using a split bobbin, and then the split bobbin is pulled out, or the CF is taken up on an air-back type bobbin, and then air is let out to be coreless. Thus, as the CF is taken up corelessly,, the CF can be smoothly taken out to improve efficiency of production. |
