| 摘要 |
941,199. Spinning polypropylene. MONTECATINI SOC. GENERALE PER L'INDUSTRIA MINERARIA E CHIMICA. Aug. 24, 1962 [Aug. 29, 1961], No. 32607/62. Heading B5B. In melt-spinning crystalline polypropylene, the fibres are heated to form 130‹ to 300‹ C. on leaving the spinneret but before stretching or stabilization and finishing. The preferred crystalline polypropylene has an intrinsic viscosity of 2 to 5, determined in tetrahydronaphthalene at 130‹ C. Preferably the polypropylene is extruded through spinneret holes having a length/diameter ratio higher than 1, and the resulting fibres heated by passing through a heated tubular column placed immediately beneath the spinneret, and having a diameter 2.5 cms. larger than the diameter of the array of spinneret holes and a length of 2 cms. to 1 metre. The extruded fibres are preferably subsequently stretched in a ratio between 1: 2 and 1: 10 at temperatures between 80‹ C. and 150‹ C. After stretching, the fibres may be subjected to thermal stabilization and finishing treatments. The crystalline polypropylene may be mixed with stabilizers, opacizers, organic or inorganic pigments, dyes or tinctorial modifiers. Preferred tinctorial modifiers are basic nitrogen compounds obtained by condensation of epichlorohydrin with amines. A preferred stabilizer is a mixture (0.02-2% by weight) of the polymer, of an aliphatic thioester, a dialkylphenol sulphide and calcium stearate. Fibres containing a tinctorial modifier may be subjected, before or after stretching, to the action of formaldehyde, diisocyanates or diepoxy compounds to render the modifier water insoluble. |
