Provided is a method for producing an absorbent article comprising a water-absorbing resin having an excellent initial water absorption speed under load even substantially without adding a liquid permeability enhancer.

The method steps for producing the water-absorbing resin includes the step of polymerizing a monomer while adding certain polyalkylene glycol thereto so as to generate, during or after the polymerization, a crosslinked hydrogel polymer containing the polyalkylene glycol of a specific molecular weight, wherein the crosslinked hydrogel polymer has a centrifuge retention capacity within a given range and a final water-absorbing resin to be obtained has various physical properties (CRC, AAP, SFC, FSR) being within given ranges.

The present invention relates to a method for producing an ethylene-based copolymer, and more particularly, to a method for producing an ethylene-based copolymer capable of increasing process efficiency by preventing plugging and corrosion of a facility. The method for producing an ethylene-based copolymer includes a producing mode and a washing mode of which one is selectively performed. The producing mode includes: a) hyper-compressing primary compressed ethylene, and a mixture including a carboxylic acid-containing comonomer and a polar solvent to produce a compressed material; b) reacting the compressed material to produce a reaction product including an ethylene-based copolymer; and c) separating and recovering unreacted residues from the reaction product and introducing the unreacted residues into the mixture of step a). The washing mode includes: re-supplying the compressed material produced in step a) to step a) as a mixture, without performing step b).

Provided is a method for producing a thiocarbonylthio group-removed polymer, including a step of irradiating a mixed solution which contains a polymer having a thiocarbonylthio group at a terminal of a main chain and contains at least one hydroxyl group-containing compound of an alcohol compound or a phenol compound to remove the thiocarbonylthio group from the polymer.

Provided is a method for producing a thiocarbonylthio group-removed polymer, including a step of irradiating a mixed solution which contains a polymer having a thiocarbonylthio group at a terminal of a main chain and contains at least one hydroxyl group-containing compound of an alcohol compound or a phenol compound to remove the thiocarbonylthio group from the polymer.

A method for producing a polymer solution including a methacrylate copolymer having a weight average molecular weight of not less than 100,000, a weight average molecular weight/number average molecular weight of 1.01 to 1.8 and a glass transition temperature of not more than 40° C. and including methyl methacrylate units and alkyl (meth)acrylate units containing a C10-36 alkyl group, and a first solvent having a boiling point of not less than 200° C., through steps including a step (I) of preparing the methacrylate copolymer by polymerizing monomers in a second solvent having a boiling point of below 200° C., and a step (II) of mixing the solution from the step (I) which includes the methacrylate copolymer and the second solvent, with the first solvent, and removing the second solvent to raise the content of the first solvent to not less than 10 mass % of the polymer solution.

The present invention provides a method for storing a polycarboxylic acid copolymer solution capable of preventing or reducing cloudiness and an increase in viscosity of a polycarboxylic acid copolymer solution after storage. The present invention relates to the method for storing a solution of a polycarboxylic acid polymer, the polycarboxylic acid polymer having a weight-average molecular weight of 1,000 to 20,000 and a degree of neutralization of 15 mol % or lower based on 100 mol % of a total of carboxyl groups and salts thereof in the polycarboxylic acid polymer, the polycarboxylic acid polymer containing a structural unit derived from an unsaturated carboxylic acid monomer in a content of 85 to 100 mol % based on 100 mol % of structural units derived from all monomers, the storage method comprising storing at 40° C. or higher.

The present invention provides a method for storing a polycarboxylic acid copolymer solution capable of preventing or reducing cloudiness and an increase in viscosity of a polycarboxylic acid copolymer solution after storage. The present invention relates to the method for storing a solution of a polycarboxylic acid polymer, the polycarboxylic acid polymer having a weight-average molecular weight of 1,000 to 20,000 and a degree of neutralization of 15 mol % or lower based on 100 mol % of a total of carboxyl groups and salts thereof in the polycarboxylic acid polymer, the polycarboxylic acid polymer containing a structural unit derived from an unsaturated carboxylic acid monomer in a content of 85 to 100 mol % based on 100 mol % of structural units derived from all monomers, the storage method comprising storing at 40° C. or higher.

A belt drier arrangement for drying an aqueous polymer gel and for comminuting the dried polymer gel to give dried polymer particles, having: a belt drier having a drier setup and a conveyor belt for receiving and for drying the aqueous polymer gel to give a dry cake or fragments on a receiving surface of the conveyor belt, and a comminution arrangement, disposed downstream of the drier setup in product flow direction, for comminution of the dried polymer gel of the dry cake or fragments to give dried comminuted polymer particles. The comminution arrangement has a comminutor in the form of a milling drum which is disposed with an upper working line of a working edge of the milling drum at the level of or above a receiving surface of a conveyor belt, for mill processing of the dry cake or of the fragments, where the milling drum is designed to eject comminuted dried polymer particles of the dry cake or of the fragments in the downward direction.

A belt drier arrangement for drying an aqueous polymer gel and for comminuting the dried polymer gel to give dried polymer particles, having: a belt drier having a drier setup and a conveyor belt for receiving and for drying the aqueous polymer gel to give a dry cake or fragments on a receiving surface of the conveyor belt, and a comminution arrangement, disposed downstream of the drier setup in product flow direction, for comminution of the dried polymer gel of the dry cake or fragments to give dried comminuted polymer particles. The comminution arrangement has a comminutor in the form of a milling drum which is disposed with an upper working line of a working edge of the milling drum at the level of or above a receiving surface of a conveyor belt, for mill processing of the dry cake or of the fragments, where the milling drum is designed to eject comminuted dried polymer particles of the dry cake or of the fragments in the downward direction.

The present invention is directed to a process for separating an olefin copolymer from volatile gases using a flash separator. The flash separator can be used with a solution or high pressure process. The mass transport of volatile gases from the viscous polymer melt is increased.