Process for the recovery of epsilon-caprolactam from nylon 6-containing multi-component material

A process for recovering purified ε-caprolactam from material derived from nylon 6-containing multi-component material in a plant, wherein the plant comprises

• a depolymerization section [B],
• a recovery section [C], and
• a purification section [D],
• and wherein the process comprises the steps of:
• a) providing a pre-concentrated nylon 6-containing material that has been obtained by extracting a nylon 6-containing multi-component material with one or more solvents to obtain a solid pre-concentrated nylon 6-containing material, which is enriched in nylon 6 as compared to the nylon 6-containing multi-component material, and charging said pre-concentrated material derived from nylon 6-containing multi-component material to the depolymerization section [B];
• b) depolymerizing the material derived from nylon 6-containing multi-component material in the depolymerization section [B] at a temperature ranging from 180° C. to 400° C., so that an ε-caprolactam comprising stream is obtained;
• c) discharging the ε-caprolactam comprising stream from the depolymerization section [B] and recovering crude ε-caprolactam from said stream in the recovery section [C];
• and
• d) purifying said crude-caprolactam in the purification section [D] to obtain purified & caprolactam wherein the purification comprises the steps of
• (i) extracting the crude ε-caprolactam with an organic solvent, whereby an organic phase is obtained, and wherein the organic phase comprises the organic solvent, ε-caprolactam and impurities;
• and
• (ii) a) solvent switching based on back-extraction with water;
• or
• (ii) b) solvent switching based on solvent swap distillation;
• and
• (iii) distillative removal of impurities with lower- or higher-boiling points than ε-caprolactam under vacuum conditions;
• and
• (iv) obtaining purified ε-caprolactam by crystallization of ε-caprolactam from a solution comprising ε-caprolactam and impurities at a temperature of 10 to 95° C.;
• and wherein the nylon 6-containing multi-component material is or comprises
• a) a multi-layer film that contains at least one layer comprising or consisting of nylon 6 and at least one layer comprising or consisting of a polyolefin,
• b) a multi-layer film that contains at least one layer comprising or consisting of nylon 6 and at least two layers comprising or consisting of a polyolefin, wherein the at least one layer comprising or consisting of nylon 6 is sandwiched in between two or more layers comprising or consisting of a polyolefin, and/or
• c) a multi-component material comprising nylon 6 and at least one polyolefin, wherein the nylon 6 is present in the nylon 6-containing multi-component material as a separate domain and/or as a mixture with the at least one polyolefin.