A method for providing particles of polyvinyl chloride, wherein the particles offer improved chlorinating efficiency, the method comprising (i) providing polyvinyl chloride particles; and (ii) introducing a chlorination accelerant to the polyvinyl chloride particles to thereby provide polyvinyl chloride particles having an accelerant associated therewith.

A method for providing particles of polyvinyl chloride, wherein the particles offer improved chlorinating efficiency, the method comprising (i) providing polyvinyl chloride particles; and (ii) introducing a chlorination accelerant to the polyvinyl chloride particles to thereby provide polyvinyl chloride particles having an accelerant associated therewith.

The production method includes: a gel-crushing step of grinding a crosslinked hydrogel polymer to obtain a particulate crosslinked hydrogel polymer; a heating drying step of obtaining dried particles from the particulate crosslinked hydrogel polymer by using a continuous stirring drying machine; a post-crosslinking step of post-crosslinking the particulate crosslinked hydrogel polymer or the dried particles; and a sizing step of adjusting a particle size of the dried particles or the post-crosslinked dried particles to obtain water-absorbent resin powder. The particulate crosslinked hydrogel polymer contains a gel fluidizer. A gel temperature of the particulate crosslinked hydrogel polymer containing the gel fluidizer, the gel temperature being measured by a contact thermometer, is not lower than 50° C. In the production method, the dried particles or the post-crosslinked dried particles is forcedly cooled before the sizing step.

A method for producing a crosslinking polymer gel, the method including polymerizing a monomer composition containing at least one (meth)acrylic acid compound selected from the group consisting of (meth)acrylic acid and a salt thereof and benzaldehyde to obtain a crosslinking polymer gel, in which a centrifuge retention capacity of crosslinking polymer particles obtained by coarsely crushing, drying, and pulverizing the crosslinking polymer gel is 60 g/g or more. A monomer composition for obtaining a crosslinking polymer gel, the monomer composition containing at least one (meth)acrylic acid compound selected from the group consisting of (meth)acrylic acid and a salt thereof, and benzaldehyde, in which a centrifuge retention capacity of crosslinking polymer particles obtained by coarsely crushing, drying, and pulverizing the crosslinking polymer gel is 60 g/g or more.

The present invention provides polymer particles capable of being dissolved in a dissolving medium without generating an unmixed lump and capable of uniformly improving the viscosity of a composition, and a thickener using the polymer particles. The polymer particles of the present invention have a number average particle diameter of 1 to 50 .Math.m and a coefficient of variation in a number-based particle size distribution of 30% or more, wherein where the weight average molecular weight of the whole polymer particles is defined as A, the weight average molecular weight of small particles having a cumulative number percentage of 5% or less counted from the smaller diameter side in the number-based particle size distribution of the polymer particles is defined as B, and the weight average molecular weight of large particles having a particle diameter of 5 times or more the number average particle diameter of the polymer particles is defined as C, polymer particles satisfy the following formulas (1) and (2).

[00001]$0.90\le \left(\text{B}/\text{A}\right)<1.0$

[00002]$\left(\text{C}/\text{B}\right)<1.25$

The present invention provides polymer particles capable of being dissolved in a dissolving medium without generating an unmixed lump and capable of uniformly improving the viscosity of a composition, and a thickener using the polymer particles. The polymer particles of the present invention have a number average particle diameter of 1 to 50 .Math.m and a coefficient of variation in a number-based particle size distribution of 30% or more, wherein where the weight average molecular weight of the whole polymer particles is defined as A, the weight average molecular weight of small particles having a cumulative number percentage of 5% or less counted from the smaller diameter side in the number-based particle size distribution of the polymer particles is defined as B, and the weight average molecular weight of large particles having a particle diameter of 5 times or more the number average particle diameter of the polymer particles is defined as C, polymer particles satisfy the following formulas (1) and (2).

[00001]$0.90\le \left(\text{B}/\text{A}\right)<1.0$

[00002]$\left(\text{C}/\text{B}\right)<1.25$

The present invention relates to an ethylene-vinyl alcohol copolymer (EVOH) resin composition, an EVOH film formed therefrom, and a multilayer structure containing the same. The surface roughness of the EVOH resin composition is the peak material volume (Vmp) between 0.0008 and 10 μm.sup.3/μm.sup.2. The EVOH of the invention can reduce the torque output during processing, and can obtain the EVOH film with excellent appearance.

The present invention relates to an ethylene-vinyl alcohol copolymer (EVOH) resin composition, an EVOH film formed therefrom, and a multilayer structure containing the same. The surface roughness of the EVOH resin composition is the peak material volume (Vmp) between 0.0008 and 10 μm.sup.3/μm.sup.2. The EVOH of the invention can reduce the torque output during processing, and can obtain the EVOH film with excellent appearance.

The present invention relates to a superabsorbent polymer showing a low degree of decrease in absorption capacity, and a preparation method thereof. Specifically, the present invention provides a superabsorbent polymer having an excellent rewetting prevention ability such that moisture hardly leaks out under pressure even after a certain time, and a preparation method thereof, by preparing an acrylic resin with a high molecular weight main chain that is evenly cross-linked for maintaining high gel strength by minimizing an amount of an initiator with respect to a monomer.

The present invention relates to an ethylene-vinyl alcohol copolymer (EVOH) resin composition, an EVOH film formed therefrom, and a multilayer structure containing the same. The surface roughness of the EVOH resin composition is a kurtosis (Sku) ranging from 0.05 to 100. The EVOH of the invention can reduce the torque output during processing, and can obtain the EVOH film with excellent appearance.