Method for producing ethylene-vinyl alcohol copolymer resin composition pellets

• Main Authors: NAGAE, HIROYUKI, SHIOTA, HIROTAKA, KATAHIRA, ERIKO
• Format: Patent
• Language: Chinese; English
• Published: 16.08.2024
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; MAKING GRANULES OR PREFORMS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PREPARATION OR PRETREATMENT OF THE MATERIAL TO BESHAPED; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIALCONTAINING PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

This method for manufacturing EVOH resin composition pellets comprises: a first drying step (I) for introducing EVOH hydrous pellets having a water content W0 of 25-50 mass% into a dryer to reduce the water content W1 of the pellets to 5-25 mass%; a melting-kneading step (II) for introducing the pellets obtained in the first drying step (I) into an extruder, adding a water dispersion liquid or an aqueous solution containing an additive, and melting and kneading the mixture; a cutting step (III) for cutting the molten resin composition discharged from the extruder to obtain EVOH resin composition hydrous pellets having a water content W2 of 5-20 mass%; and a second drying step (IV) for drying the hydrous pellets obtained in the cutting step (III) to obtain EVOH resin composition pellets having a water content W3 of 0.5 mass% or less. The reduction (W0-W1) of the water content in the first drying step (I) is 10-45 mass%. Accordingly, it is possible to efficiently obtain EVOH resin composition pellets by increas