The present invention relates to salts of etheramines and polymeric acid, and in particular to salts of etheramines and polycarboxylic acid and their manufacturing process.

Disclosed are water-absorbent resin particles comprising a crosslinked polymer comprising a monomer unit derived from a water-soluble ethylenically unsaturated monomer, wherein an initial swelling force as measured according to a swelling force test conducted by a predetermined method is 8 N or more, and further, a ratio of the particles having a particle diameter of more than 250 μm and 850 μm or less is 70% by mass or more and a ratio of the particles having a particle diameter of 250 μm or less is 20% by mass or less, with respect to the total amount of the water-absorbent resin particles.

A resin composition suitable for an optical compensation film, an optical compensation film using the same, which is excellent in the retardation characteristics and wavelength dispersion characteristics, and a production method of an optical compensation film. A resin composition containing, as resin components, from 30 to 99 wt % of a cellulose-based resin represented by the following formula (1) and from 1 to 70 wt % of a cinnamic acid ester copolymer:

##STR00001## where each of R.sub.1, R.sub.2 and R.sub.3 independently represents hydrogen or a substituent having a carbon number of 1 to 12.

Disclosed is a method of preparing a superabsorbent polymer, including a) drying and pulverizing a hydrogel polymer, and then classifying into a first fine powder having a particle size of less than 150 μm and a base polymer having a particle size of 150 to 850 μm; b) mixing a portion of the first fine powder, water and an additive, thus preparing a first fine-powder regranulate; c) passing the first fine-powder regranulate through a chopper and then performing drying and pulverizing; and d) classifying the pulverized first fine-powder regranulate into a superabsorbent polymer having a particle size of 150 to 850 μm and a second fine powder having a particle size of less than 150 μm, thus yielding the superabsorbent polymer.

A method of preparing a superabsorbent polymer is provided. The method of preparing the superabsorbent polymer according to the present disclosure is able to provide the superabsorbent polymer having an improved absorption rate while having superior centrifuge retention capacity (CRC) and absorbency under pressure (AUP).

A method of preparing absorbent polymer granules is provided. The method of preparing fine particle granules according to the present disclosure may provide granules of which re-breaking is minimized due to a superior binding force between fine particles.

A composite film 10 according to the present invention is provided with: a resin film 1 which is formed of a cured product of a photocurable adhesive composition; and solid particles 3 which are affixed, in the form of a single layer, to the resin film 1, while having edges thereof exposed from one and the other main surfaces of the resin film 1. The resin film 1 is formed by irradiating an adhesive layer 1a in a semi-cured state with light 13, said adhesive layer 1a being formed of the adhesive composition.

To provide a method for producing a water-absorbing resin by which problems caused by addition of a particulate additive or water-absorbing resin fine powder can be prevented and a water-absorbing resin having high physical properties can be stably and efficiently obtained.

A method for producing a polyacrylic acid (salt)-based water-absorbing resin, the method including: an aqueous monomer solution preparation step for preparing an aqueous solution containing a monomer having an acrylic acid (salt) as a main component; a polymerization step for polymerizing the monomer to obtain a hydrogel-forming crosslinked polymer; and a drying step for drying the hydrogel-forming crosslinked polymer to obtain a dry polymer, wherein the method further includes an adding step for adding a particulate additive to the aqueous monomer solution and/or the hydrogel-forming crosslinked polymer, and in the adding step, an oxygen concentration in an ambient atmosphere of the particulate additive is set to 5% by volume or less.

Provided are: a water-absorbent resin which, when used as an absorbent material, retains a high water-absorption performance, increases the diffusivity of a to-be-absorbed liquid and makes it possible to effectively decrease the amount of re-wet; and an absorbent article formed using an absorbent material including the water-absorbent resin. The water-absorbent resin according to the present invention is a water-absorbent resin obtained by polymerizing a water-soluble ethylenically monomer in the presence of an internal-crosslinking agent and thereafter post-crosslinking the polymer with a post-crosslinking agent, characterized in that when subjected to a liquid flow test, the water-absorbent resin has an effective absorbent material index (K) indicated by equation (I) of 250 or greater.

Effective absorbent material index (K)=[(the amount of liquid flow) (g)]×[(artificial-urine absorption ratio) (g/g)]  (I)

To provide water-absorbing resin powder particularly useful for a sanitary article, water-absorbing resin powder containing a polyacrylic acid (salt)-based water-absorbing resin as a main component is surface-crosslinked, and satisfies (1) to (3) below: (1) a proportion of a water absorbent resin powder having a particle size of not less than 150 μm and less than 850 μm is not less than 90 weight %; (2) a water absorption time according to a vortex method is not more than 42 seconds; and (3) an elastic modulus index (600-500) is not less than 5500.