Method for filling particulate water-absorbing agent having as a main component water-absorbing resin
There is provided a filling method which is capable of suppressing uneven distribution of particle diameter and suppressing property decrease of the particulate water-absorbing agent. The method for filling the particulate water-absorbing agent according to the present invention includes a abutting step for making a member for filling the particulate water-absorbing agent abutted on a vibrator; a supplying step for supplying the particulate water-absorbing agent to the member for filling; and a vibration step for vibrating the particulate water-absorbing agent present in the member for filling by vibrating the vibrator. Preferably, the supplying step is performed by dividing into a plurality of times. Preferably, the vibration step includes an intermediate vibration step performed at a stage where a part of a plurality of times of the supplying steps is completed, and a final vibration step performed at a stage where all of a plurality of times of the supplying steps is completed. Total filling mass W 2 is set preferably at 500 kg to 1500 kg.
1. A method for filling a particulate water-absorbing agent having as a main component a water-absorbing resin, comprising:
an abutting step for making a member for filling the particulate water-absorbing agent abutted on a vibrator;
a supplying step for supplying the particulate water-absorbing agent to the member for filling; and
a vibration step for vibrating the particulate water-absorbing agent present in the member for filling by vibrating the vibrator,
wherein the particulate water-absorbing agent is a polyacrylic acid or a salt based water-absorbing resin and further includes a polyamine polymer, a polyvalent metal or a salt thereof, or a water-insoluble inorganic fine particle.
2. The filling method according to claim 1 , wherein at least a part of the supplying step and at least a part of the vibration step are performed at the same time.
3. The filling method according to claim 1 , wherein in the supplying step and the vibration step, relative humidity around the member for filling is 30% to 65%.
4. The filling method according to claim 1 , wherein in the vibration step, the vibrator is vibrated in a frequency of vibration of 30 Hz to 120 Hz.
5. The filling method according to claim 1 , wherein the member for filling is a flexible container bag; and in the abutting step, the flexible container bag is mounted on the vibrator.
6. The filling method according to claim 1 , wherein the supplying step is performed by dividing into a plurality of times;
the vibration step comprises an intermediate vibration step performed at a stage where a part of a plurality of times of the supplying steps is completed, and a final vibration step performed at a stage where all of a plurality of times of the supplying steps are completed.
7. The filling method according claim 6 , wherein in the intermediate vibration step, ratio (W 1 /W 2 ) of mass [W 1 (kg)] of the particulate water-absorbing agent present in the member for filling to total mass [W 2 (kg)] of the particulate water-absorbing agent filled is 0.3 to 0.6; and total mass [W 2 (kg)] of the particulate water-absorbing agent filled is 500 kg to 1500 kg.
8. The filling method according to claim 1 , wherein AAP (4.8 kPa) of the particulate water-absorbing agent is equal to or higher than 15 g/g.
9. The filling method according to claim 1 , wherein temperature of the particulate water-absorbing agent in the vibration step is 30 to 70° C.
10. The filling method according to claim 1 , wherein the water-absorbing resin is an irregular shaped pulverized substance obtained by continuous kneader polymerization or continuous belt polymerization.
11. The filling method according to claim 1 , wherein the particulate water-absorbing agent further includes a polyvalent metal or a salt thereof.
12. The filling method according to claim 11 , wherein the particulate water-absorbing agent is formed by mixing the polyvalent metal or a salt thereof with the water-absorbing resin as an aqueous solution.
13. The filling method according to claim 11 , wherein the polyvalent metal or a salt thereof is an aluminum salt.
14. The filling method according to claim 11 , wherein the polyvalent metal or a salt thereof is in an amount of 0.001 to 5 parts by weight, relative to 100 parts by weight of the water-absorbing resin.
15. The filling method according to claim 1 , wherein the polyamine polymer, the polyvalent metal or a salt thereof, or the water-insoluble inorganic fine particle is in an amount of 0.001 to 10 parts by weight, relative to 100 parts by weight of the water-absorbing resin.