Verfahren zum Polymerisieren von Lactamen

摘要

1,223,175. Anionic lactam polymerization. ALLIED CHEMICAL CORP. 22 July, 1968 [21 July, 1967; 24 July, 1967], No. 34880/68. Heading C3R. Lactams are polymerized in the presence of an alkali metal or alkaline earth metal lactam salt as catalyst and as co-catalyst a compound of formula wherein either X is O and Y is a 5- or 6-membered ring containing nitrogen which bonded to the rest of the molecule by a direct link to a ring nitrogen atom or through a sulphur atom to a ring carbon atom or X is S and Y is -S-CO-(O) m -R where R is a hydrocarbon radical and m is 0 or 1. The lactam may have 6-12 carbon atoms, e.g. epsilon - caprolactam. A lactam-catalyst mixture may be prepared by adding to the lactam sufficient of an alkali metal or alkaline earr,h metal or basic compound thereof, e.g. LiAlH 4 , to convert 0À1-5 mole per cent of the lactam to lactam salt and heating the mixture above the m.p. of the lactam. The process should be carried out under anhydrous conditions, i.e. less than 50 p.p.m. of water or other proton donors should be present. The product may be stored or reacted immediately with the co-catalyst. The co-catalyst may be 1 - (2 - benzoxazoyl)benzotriazole, di - (2 - benzoxazolyl) thioether, 31-(21-benzoxazoyl)-3,5- dimethylpyrazole, 3 - (21- benzoxazoyl)- benzoxazoline - 2, 2 - (ethoxycarbonylthio)- benzothiazole, 2 - benzoylthiobenzthiazole or 2 - (n - butyloxy - carbonylthio)benzothiazole. They may be prepared by reacting the sodium salt of 2 - mercaptobenzothiazole with an equimolar amount of a compound of formula R(O) m COCl in a solvent, e.g. xylene, or heating 2 - chlorobenzoxazole with an equimolar amount of a compound of formula YH, where H is an active hydrogen atom, under anhydrous conditions, in a solvent, e.g. xylene, at a temperature between 50‹ C. and reflux temperature until HCl evolution ceases. 0À1-10 moles of co-catalyst may be used per mole of catalyst and 0À05-1À5 moles of co-catalyst may be used per mole of lactam. The reaction temperature e.g. 110-215‹ C. may be between the m.p. of the lactam and the softening point of the polymer so that the product is a solid shaped article. Fillers and plasticizers may be added to the reaction mixture. In Example 8, the lactam is polymerized partially in the presence of the catalyst only before the co-catalyst is added.