Abstract: Provided is a method that can stably produce polyaryletherketone that has a high degree of polymerization and can be easily recovered. The method for producing polyaryletherketone includes: a polycondensation step of carrying out desalting polycondensation in a reaction solvent; and a cooling step of cooling a reaction mixture after desalting polycondensation is completed. When the method is implemented, the polycondensation step is carried out in a hydrophilic solvent under pressurized conditions, and the polymerization temperature in the polycondensation step is at or above the boiling point of the hydrophilic solvent at ambient pressure. In addition, the polymer content in terms of monomers at the time of cooling in the cooling step is from 1 part by mass to 50 parts by mass, per 100 parts by mass of the hydrophilic solvent in the reaction mixture.

Abstract: Provided is a method that can stably produce polyaryletherketone that has a high degree of polymerization and can be easily recovered. The method for producing polyaryletherketone includes: a polycondensation step of carrying out desalting polycondensation in a reaction solvent; and a cooling step of cooling a reaction mixture after desalting polycondensation is completed. When the method is implemented, the polycondensation step is carried out in a hydrophilic solvent under pressurized conditions, and the polymerization temperature in the polycondensation step is at or above the boiling point of the hydrophilic solvent at ambient pressure. In addition, the polymer content in terms of monomers at the time of cooling in the cooling step is from 1 part by mass to 50 parts by mass, per 100 parts by mass of the hydrophilic solvent in the reaction mixture.

Abstract: A method of recycling a laminate shaped product, including the steps of: breaking a shaped product having a laminate structure including at least one layer of aliphatic polyester resin in addition to a principal resin layer, storing resultant broken pieces in a moisturizing environment to adjust a moisture content of the aliphatic polyester resin (layer) to at least 0.5 wt. %, and then washing the broken pieces with alkaline water to remove the aliphatic polyester resin layer, thereby recovering the principal resin. As a result, it becomes possible to shorten an induction period in the alkaline water washing step that is a principal process step, thereby rationalizing the entire process.

Abstract: A method of recycling a laminate shaped product, including the steps of: breaking a shaped product having a laminate structure including at least one layer of aliphatic polyester resin in addition to a principal resin layer, storing resultant broken pieces in a moisturizing environment to adjust a moisture content of the aliphatic polyester resin (layer) to at least 0.5 wt. %, and then washing the broken pieces with alkaline water to remove the aliphatic polyester resin layer, thereby recovering the principal resin. As a result, it becomes possible to shorten an induction period in the alkaline water washing step that is a principal process step, thereby rationalizing the entire process.

Abstract: A packaged product formed by enclosing a content material, such as food or beverage, sanitary products or medical products, within a packaging material including at least a layer of hydrophilic resin, is heat-treated with hot water for, e.g., boil sterilization or retort sterilization. The hot water is caused to contain a water-soluble compound in an amount substantially exceeding a level contained in tap water, whereby it becomes possible to suppress the opalescence of the packaging material causing inferior appearance or transparency and leading to a lowering in gas-barrier property, which has been problematic in the conventional boil or retort hot water treatment.