JP2005194524A5

JP2005194524A5 -

Info

Publication number: JP2005194524A5
Application number: JP2004358955A
Authority: JP
Filing date: 2004-12-10
Publication date: 2008-02-14
Anticipated expiration: 2024-12-10

Claims

A water-absorbing agent mainly composed of a water-absorbing resin having a crosslinked structure obtained by polymerizing a monomer component mainly composed of an acid group-containing unsaturated monomer ,
The water-absorbing agent is subjected to a surface treatment,
And the water absorbing agent is
(1) Thermal insulation index 1 (maximum temperature decrease per minute in 5 to 10 minutes after 10-fold swelling with 0.90 wt% sodium chloride aqueous solution at 50 ° C.) is 0 to 3.0 ° C./minute,
(2) Absorption capacity without load (value for 30 minutes) with respect to a 0.90% by weight sodium chloride aqueous solution is 34 g / g or less,
(3) Absorption capacity under pressure at 2.0 kPa against a 0.90 wt% aqueous sodium chloride solution (60 minutes value) is less than 30 g / g,
(4) The flow inductive (SFC) value of the 0.69 wt% sodium chloride aqueous solution is less than 20 × 10 ⁻⁷ cm ³ sec / g,
A water-absorbing agent characterized by satisfying all the requirements (1) to (4).

The acid group-containing unsaturated monomer is acrylic acid (salt), and the other monomer in the monomer component is 0 to 30 mol% based on acrylic acid (salt). The water-absorbing agent according to claim 1.

The water-absorbing agent is composed of particles, particles having a particle size of 600 to 300 μm as defined by sieving classification are composed of 60% by weight or more, and particles having a particle size of less than 150 μm are composed of 3% by weight or less (lower limit 0% by weight). The water-absorbing agent according to claim 1, wherein a logarithmic standard deviation of (σζ) satisfies 0.250 to 0.400.

The water-absorbing agent according to any one of claims 1 to 3, further comprising water-insoluble inorganic fine particles in addition to the water-absorbing resin.

The heat retention index 2 (the gel surface temperature after 10-fold swelling with a 0.90% by weight sodium chloride aqueous solution at 50 ° C, 10 minutes later) is 20 ° C or higher. Water-absorbing agent.

6. The heat retention index 3 (the time for the gel surface temperature to reach 37 ° C. after 10-fold swelling with a 0.90% by weight sodium chloride aqueous solution at 50 ° C.) is 120 seconds or more. The water-absorbing agent described in 1.

The water-absorbing agent according to any one of claims 1 to 6, wherein a mass-average particle diameter (specified by sieve classification) is 400 to 600 µm.

The water-absorbing agent according to claim 1, further comprising a polyol in addition to the water-absorbing resin.

A molded absorbent comprising the water-absorbing agent according to any one of claims 1 to 8 and a hydrophilic fiber.

It is an absorber of Claim 9, Comprising: Content of the said water absorbing agent with respect to the total weight of the water absorbing agent in any one of Claims 1-8 and a hydrophilic fiber is 20 weight% or more. Characteristic absorber.

An absorbent article comprising the absorbent body according to claim 9 or 10, a top sheet having liquid permeability, and a back sheet having liquid impermeability.

A method for producing a water-absorbing agent mainly comprising a water-absorbing resin having a crosslinked structure obtained by polymerizing a monomer component mainly comprising an acid group-containing unsaturated monomer ,
A polymerization step for obtaining a water-absorbent resin by polymerizing a monomer component mainly composed of an acid group-containing unsaturated monomer;
A surface cross-linking process (surface treatment process) for performing a surface cross-linking process (surface treatment) on the water absorbent resin obtained by the polymerization process,
In the polymerization step,
The water-absorbent resin is a particle, and the water-absorbent resin has an absorption capacity without load (30 minutes value) with respect to 0.90% by weight sodium chloride of 35 g / g or more,
(1) The particles are 60% by weight or more of particles having a particle diameter of 600 to 300 μm defined by sieve classification, and 3% by weight or less of particles having a particle size of less than 150 μm,
(2) Logarithmic standard deviation (σζ) of particle size distribution is 0.250-0.400,
Polymerized to meet each specific particle size of
In the surface crosslinking step,
A method for producing a water-absorbing agent, wherein the water-absorbent resin satisfying each specific particle size in the polymerization step is subjected to surface cross-linking treatment to perform surface cross-linking.

In the surface crosslinking step,
The water absorbent resin satisfying each specific particle size in the polymerization step,
Absorption capacity without load (value for 30 minutes) with respect to 0.90% by weight sodium chloride aqueous solution is 34 g / g or less, and
Absorption capacity under pressure at 2.0 kPa against a 0.90% by weight sodium chloride aqueous solution (60 minutes value) is less than 30 g / g,
The method for producing a water-absorbing agent according to claim 12, wherein surface crosslinking treatment is performed until