Rapidly crystallizing polyphenylene sulphide material containing sulfonic acid ester

Highly crystalline, rapidly crystallizing thermoplatic material comprising

• (a) 70-99.5% by weight of a polyphenylene sulphide with a melt viscosity of at least 5 Pacal-seconds, measured at 306.degree. C. and a shearing stress of 10.sup.2 Pascal units, and
• (b) 0.5-30% by weight based on (a) and (b) of a sulphonic acid ester prepared by reacting
• (i) an alkylsulphonyl chloride of the formula
• R.sup.1 --CH.sub.2 --(CHR.sup.2).sub.n --CH.sub.2 R.sup.3
• wherein
• R.sup.1, R.sup.2 and R.sup.3 independently of one another are H, Cl or SO.sub.2 Cl, at least one of which must be SO.sub.2 Cl, and
• n represents an integer from 3 to 33, and wherein the molar ratio C/SO.sub.2 Cl is 35 to 1.25, with
• (ii) equivalent amounts of a compound of the formula (I) ##STR5## wherein R.sup.4 denotes a bivalent aromatic radical with 6-14 Carbon atoms and
• R.sup.5 denotes an alkyl, cycloalkyl or aryl radical with 1-20 Carbon atoms or H,
• and wherein
• m represents the number 0 or 1,
• or the formula (II) ##STR6## wherein R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are identical or different and denote a hydrogen atom, an alkyl radical with 1-4 Carbon atoms or a chlorine or bromine atom and X is a single bond, or X is an alkylene or alkylidene radical with 1-8 Carbon atoms, a cycloalkylene or cycloalkylidene radical with 5-15 Carbon atoms, S, ##STR7## SO.sub.2, --O--or ##STR8##