| 摘要 |
Linear aromatic polyamides are continuously prepared from a diammonium dicarboxylate salt of a diamine NH2-X-NH2 and a dicarboxylic acid HOCO-Y-COOH or from an amino-acid NH2-Z-COOH where X is a chain of p-methylene groups and q m- or p-phenylene groups, Y is a chain of r-methylene groups and s m- or p-phenylene groups and Z is a chain of t-methylene groups and u m- or p-phenylene groups, p, q, r, s, t and u being zero or positive integers, q and s being 0-2 at least one being greater than 0, u being 1 or 2, p being at least 6 if q is 0 but otherwise at least 2, r being at least 4 if s is 0, the sum of p and r being at least 6, t being at least 3, the phenylene groups not being directly connected to the amino groups, and X, Y and Z being optionally alkyl substituted and optionally containing -O- links other than -O-O-, -O-CH2-N =, and -O-(CH2)2-O-. The monomer is mixed with water and pumped along a tube of up to 3.5 cm. diameter, heated to the polymerization temperature and having a pressure of at least 14 atmospheres at the inlet decreasing to atmospheric or sub-atmospheric at the outlet but everywhere being sufficiently low to permit evolution of steam from the mixture, the rate of passage being such that at least 90% of the potential water of condensation is in fact evolved. Entirely aliphatic polyamide forming monomers may be mixed with the aromatic monomers of the invention. Monoacids and amines, e.g. acetic acid, and the difunctional acids and amines, as distinct from their salts, may also be present. Other additives are dyes, pigments, plasticizers, heat stabilizers, photostabilizers, and delustrants. Numerous examples of the monomeric reactants and the plasticizers are given. The reaction tube may be a vertical or horizontal helix made of steel the material entering at the upper or lower end. It may increase in diameter from inlet to outlet and be jacketed with hot fluid. The temperature may be 275-300 DEG C. The product may issue into a vessel or a larger diameter tube from which it may subsequently be drawn off and made into fibres, films, ribbons or shaped objects. |
