Abstract: .epsilon.-Caprolactam is continuously recovered from carpet made from nylon 6 face fibers and a backing. The carpet is fed to a separator to prepare scrap containing nylon 6 and auxiliary materials. The scrap from the separator is fed to a depolymerizing reactor to produce an .epsilon.-caprolactam containing distillate and more auxiliary materials. The .epsilon.-caprolactam in the distillate is separated from other volatiles and purified. The auxiliary materials are also recovered or re-used.

Abstract: A process for recovering caprolactam from waste containing both polycaprolactam and materials which are insoluble in acidic solvents for polycaprolactam includes agitating the waste in an acidic solvent capable of dissolving polycaprolactam without degrading the acid insoluble materials, separating the solution containing polycaprolactam from the acid insoluble materials, feeding the solution containing the polycaprolactam to a depolymerization reactor, without substantially precipitating the polycaprolactam and depolymerizing the polycaprolactam solution to obtain substantially pure caprolactam.

Abstract: A process for preparing polyamides from amide monomers in a reaction vessel where a portion of the monomers remain unreacted or form oligomers as an extractable fraction includes extracting from the polyamide unreacted amide monomers and oligomers to yield an extracted proportion by weight based on total reaction charge; reducing the oligomer concentration of the extracted proportion relative to the total extract concentration; and returning the extract to the reaction vessel as substantially the same proportion as extracted by weight based on the total reaction charge, so that, after a single extraction, throughout the process the extractable fraction remains below its equilibrium concentration.

Abstract: A process for the continuous recovery of .epsilon.-caprolactam provides a carpet made from nylon 6 fibers and having a backing to a separator to prepare scrap containing nylon 6 and waste. The scrap from the separator is fed to a depolymerizing reactor where the scrap is subjected to a depolymerization catalyst, temperatures of at least the melting point of nylon 6 and superheated steam to produce an .epsilon.-caprolactam containing distillate and more waste. The .epsilon.-caprolactam in the distillate is separated from other volatiles therein; and purified.

Abstract: A process for preparing polyamides of substantially constant cyclic dimer concentration from amide monomers includes extracting unreacted amide monomers and oligomers, reducing the oligomer concentration relative to the concentration of total extractants and then returning the extract to the reaction vessel in substantially the same total proportion as extracted.

Abstract: A molecular weight controller having particular application in the polymerization of a lactam, i.e., epsiloncaprolactam, to a polyamide, i.e., poly(epsiloncaprolactam). The molecular weight controller comprises a primary monofunctional amine, i.e., benzylamine, a primary monofunctional acid, i.e., acetic acid, and a salified aminoacid containing an aromatic, a cyclohexane, or cyclopentane moiety, i.e., 4-(aminomethyl)benzoic acid salified with p-toluenesulfonic acid. The resulting polyamide has a reduced water extractable content.

Abstract: A molecular weight controller having particular application in the polymerization of a lactam, i.e., epsiloncaprolactam, to a polyamide, i.e., poly(epsiloncaprolactam). The molecular weight controller comprises a primary monofunctional amine, i.e., benzylamine, a primary monofunctional acid, i.e., acetic acid, and a salified aminoacid containing an aromatic, a cyclohexane, or cyclopentane moiety, i.e., 4-(aminomethylbenzoic acid salified with p-toluenesulfonic acid. The resulting polyamide has a reduced water extractable content.

Abstract: A method for removing impurities from caprolactam is disclosed. The method comprises the sequential steps of treating the impure caprolactam with phosphorus pentoxide so that the impurities react therewith to form high boiling species and then distilling the so treated impure lactam to recover substantially pure caprolactam as overhead, with the impurities remaining as bottoms.