| 摘要 |
<p>For the preparation of thermoplastic moulding compositions having a high rate of crystallisation, 0.05-1.5 % by weight of an alkali metal salt or alkaline earth metal salt of an organic sulphonic acid of the given formula (I) such as, for example, the sodium salt of isethionic acid or acetyl-isethionic acid, of taurine, of N-methyl-N-palmitoyltauric acid or of an alkanesulphonic acid is added to a linear polyester of the polyethylene terephthalate type. The addition of such sulphonates, which can be carried out before, during or after the preparation of the polyester, makes it possible, owing to their double nucleating and lubricating action, to shorten the injection-moulding cycle and hence to increase the production rate and, furthermore, makes it possible to obtain manufactured products having dimensional stability and a high heat distortion point. In this way, the addition of solid inorganic substances and hence the appearance of agglomerates and cracks, which would lead to a consequent reduction in the resilience of the finished objects, are completely avoided. The technical and application characteristics of the polyester are not comprised by the addition of such sulphonates and permit a significant increase in the production rate, with the finished products having improved mechanical characteristics (resilience). R X R'SO3Me (I> where: Me = alkali metal or alkaline earth metal; R = hydrogen atom or an alkyl, aryl or arylalkyl radical having 1 to 20 carbon atoms; R' = linear or branched alkylene radical having 1 or more carbon atoms, which can contain polar groups such as -COOR'' or -CH2COOR'' in its branches, X = a -CH2 group or a polar group such as <IMAGE> where R'' is a hydrocarbon radical.r</p> |
