Provided is a method for producing a polymer, comprising: a first step for synthesizing a crude polymer by reacting a monomer containing a pyrimidinetrione structure, an imidazolidinedione structure, or a triazinetrione structure, in an organic solvent in the presence of a quaternary phosphonium salt or quaternary ammonium salt; and a second step for precipitating and separating a purified polymer by mixing a poor solvent with the crude polymer-containing solution obtained in the first step.

Provided is a method for producing a polymer, comprising: a first step for synthesizing a crude polymer by reacting a monomer containing a pyrimidinetrione structure, an imidazolidinedione structure, or a triazinetrione structure, in an organic solvent in the presence of a quaternary phosphonium salt or quaternary ammonium salt; and a second step for precipitating and separating a purified polymer by mixing a poor solvent with the crude polymer-containing solution obtained in the first step.

Disclosed are methods for purifying polyols containing oxyalkylene units that is an alkali metal catalyzed alkoxylation reaction product of an alkylene oxide and an H-functional starter. The methods include neutralizing the alkali metal ions with an aqueous solution comprising water and sulfuric acid, in which: (i) the sulfuric acid is present in an amount of no more than 5% by weight, based on the total weight of the aqueous solution, and (ii) the sulfuric acid is used in an amount of 2% to 10% more than the theoretical amount necessary to neutralize all of the alkali metal ions present. The methods can produce polyols having a low content of 2-methyl-2-pentenal.

Disclosed are methods for purifying polyols containing oxyalkylene units that is an alkali metal catalyzed alkoxylation reaction product of an alkylene oxide and an H-functional starter. The methods include neutralizing the alkali metal ions with an aqueous solution comprising water and sulfuric acid, in which: (i) the sulfuric acid is present in an amount of no more than 5% by weight, based on the total weight of the aqueous solution, and (ii) the sulfuric acid is used in an amount of 2% to 10% more than the theoretical amount necessary to neutralize all of the alkali metal ions present. The methods can produce polyols having a low content of 2-methyl-2-pentenal.

The invention provides a production method that is capable of obtaining a polyalkylene oxide having high whiteness by a simple method, and a polyalkylene oxide.

The method for producing a polyalkylene oxide of the present invention comprises a step of irradiating a high-molecular-weight polyalkylene oxide with radiation in the presence or absence of an antioxidant to obtain a polyalkylene oxide,

wherein the high-molecular-weight polyalkylene oxide has a viscosity in a 1% aqueous solution of 1500 to 16000 mPa.Math.s, when the antioxidant is present, the antioxidant is present in an amount of less than 2000 mass ppm relative to the total mass of the high-molecular-weight polyalkylene oxide, and the following formula (1):

0≤C.sup.3×I×10.sup.−8<30   (1),

wherein C is the concentration of the antioxidant used in the step, and represents the proportion (mass ppm) of the antioxidant relative to the total mass of the polyalkylene oxide, and I represents the irradiation dose (kGy) of the radiation emitted in the above step, is satisfied.

The present invention provides a production method for obtaining, by a simple method, a polyalkylene oxide whose molecular weight and polydispersity are controlled in the desired range.

The method for producing a polyalkylene oxide of the present disclosure comprises step 1 of performing a polymerization reaction of an alkylene oxide in the presence of a chain transfer agent to obtain a high-molecular-weight polyalkylene oxide; and step 2 of irradiating the high-molecular-weight polyalkylene oxide obtained in step 1 with radiation to obtain a polyalkylene oxide; wherein the amount of the chain transfer agent is 800 mass ppm or more relative to the alkylene oxide, and the high-molecular-weight polyalkylene oxide has a viscosity in a 1 mass % aqueous solution of 6000 mPas or less.

The present invention provides a production method for obtaining, by a simple method, a polyalkylene oxide whose molecular weight and polydispersity are controlled in the desired range.

The method for producing a polyalkylene oxide of the present disclosure comprises step 1 of performing a polymerization reaction of an alkylene oxide in the presence or absence of a chain transfer agent to obtain a high-molecular-weight polyalkylene oxide; and step 2 of irradiating the high-molecular-weight polyalkylene oxide obtained in step 1 with radiation to obtain a polyalkylene oxide; wherein the amount of the chain transfer agent when used is less than 300 mass ppm relative to the alkylene oxide, and the high-molecular-weight polyalkylene oxide has a viscosity in a 1 mass % aqueous solution of 7500 mPa.Math.s or more.

The present invention relates to an improved process for the preparation of poly (1,3-alkenes)-block-poly (alkylene oxides) copolymers. Furthermore, this invention also relates to the purification of crude amphiphilic block copolymers PD-b-PAO having oligomers and low molecular weight polymers.

Disclosed are processes and systems for removing water from a polyether polyol that employs a controlled temperature and pressure profile.

Disclosed are processes and systems for removing water from a polyether polyol that employs a controlled temperature and pressure profile.