초록 ▼

An object of the present invention is to make it possible, in order to form the fine powder of the water-absorbent resin into a water-absorbing material having particle diameters favorable for practical use, that a water-absorbing material which has high agglomeration strength and is excellent in th

An object of the present invention is to make it possible, in order to form the fine powder of the water-absorbent resin into a water-absorbing material having particle diameters favorable for practical use, that a water-absorbing material which has high agglomeration strength and is excellent in the quality performances is obtained at a low cost with good efficiency without causing the problems of the adhesion to such as treatment apparatus. As a means of achieving this object, a process according to the present invention for production of a water-absorbing material is a process for production of a water-absorbing material from a fine powder of a water-absorbent resin wherein the water-absorbing material is a particulate water-absorbing material having particle diameters larger than the fine powder, with the process comprising: a step (a) of adding an aqueous liquid to the fine powder of the water-absorbent resin with such as a high-speed stirring type continuous extrusion mixer 50 so that the overall average water content will be in the range of 20 to 60 weight %, whereby particles of the fine powder are agglomerated to thus obtain a particulate hydrous material 70 of the water-absorbent resin; and a step (b) of applying a mechanical compression force to the particulate hydrous material 70 and, at the same time, knead-pulverizing it, with such as a meat chopper apparatus 30, thereby obtaining particulate agglomerates 40 of the water-absorbing material.

대표청구항 ▼

What is claimed is: 1. A process for production of a water-absorbing material, which is a process for production of a water-absorbing material from a fine powder of a water-absorbent resin wherein the water-absorbing material is a particulate water-absorbing material having particle diameters large

What is claimed is: 1. A process for production of a water-absorbing material, which is a process for production of a water-absorbing material from a fine powder of a water-absorbent resin wherein the water-absorbing material is a particulate water-absorbing material having particle diameters larger than the fine powder, with the process comprising: a step (a) of adding an aqueous liquid to the fine powder of the water-absorbent resin so that the overall average water content will be in the range of 20 to 60 weight %, whereby particles of the fine powder are agglomerated to thus obtain a hydrous material of the water-absorbent resin having at least two portions with different water contents; and a step (b) of applying a mechanical compression force to the hydrous material and, at the same time, pulverizing it, thereby obtaining particulate agglomerates of the water-absorbing material. 2. A process for production of a water-absorbing material, which is a process for production of a water-absorbing material from a fine powder of a water-absorbent resin wherein the water-absorbing material is a particulate water-absorbing material having particle diameters larger than the fine powder, with the process comprising: a step (a) of adding an aqueous liquid to the fine powder of the water-absorbent resin so that the overall average water content will be in the range of 20 to 60 weight %, whereby particles of the fine powder are agglomerated to thus obtain a sheet hydrous material of the water-absorbent resin constituted by at least two layers having different water contents; and a step (b) of applying a mechanical compression force to the hydrous material and, at the same time, pulverizing it, thereby obtaining particulate agglomerates of the water-absorbing material. 3. A process for production of a water-absorbing material according to claim 1, wherein the hydrous material of the water-absorbent resin is a hydrous material of the water-absorbent resin which includes at least two layers, namely, a higher-water-content layer having a water content of 50 to 99 weight % and a lower-water-content layer having a water content of 1 to less than 50 weight %, and has a water content gradient in the hydrous material. 4. A process for production of a water-absorbing material according to claim 3, wherein, in the hydrous material of the water-absorbent resin having the water content gradient, the higher-water-content portion accounts for 2 to 98 weight % of the entirety, and the lower-water-content portion accounts for 98 to 2 weight % of the entirety. 5. A process for production of a water-absorbing material according to claim 1, wherein, in the step (a), the fine powder of the water-absorbent resin is brought into contact with the aqueous liquid under stirring to thereby obtain, as the hydrous material, a particulate hydrous material of the water-absorbent resin constituted by a lower-water-content surface layer and a higher-water-content central layer. 6. A process for production of a water-absorbing material according to claim 2, wherein, in the step (a), the fine powder of the water-absorbent resin is accumulated in layers to thereby obtain, as the hydrous material, a sheet hydrous material of the water-absorbent resin constituted by a lower-water-content central layer and higher-water-content surface layers on both sides of the lower-water-content layer. 7. A process for production of a water-absorbing material according to claim 1, wherein the particulate agglomerates of the water-absorbing material are obtained by applying the mechanical compression force to the hydrous material and, at the same time, pulverizing it within 0.001 to 5 minutes after the fine powder of the water-absorbent resin and the aqueous liquid have come into contact with each other. 8. A process for production of a water-absorbing material according to claim 1, wherein the hydrous material of the water-absorbent resin has a temperature of 40 to 100�� C. before being pulverized after the aqueous liquid has been added thereto. 9. A process for production of a water-absorbing material according to claim 1, which further comprises a drying step (c) of further drying the particulate agglomerates of the water-absorbing material after the step (b). 10. A process for production of a water-absorbing material according to claim 9, which further comprises a pulverization step (d) of further pulverizing the particulate agglomerates of the water-absorbing material after the drying step (c), thereby obtaining a water-absorbing material including a fine powder of not larger than 150 μm in particle diameter in an amount of 0 to 20 weight % relative to the water-absorbing material. 11. A process for production of a water-absorbing material according to claim 10, which further comprises a surface-crosslinking step (e) of further crosslink-treating the surfaces or surface neighborhood portions of particles of the water-absorbing material after the pulverization step (d). 12. A process for production of a water-absorbing material according to claim 11, wherein the water-absorbing material having been surface-crosslinked in the surface-crosslinking step (e) exhibits a water absorption capacity of not less than 20 g/g under a load of 4.8 kPa (0.7 psi). 13. A process for production of a water-absorbing material according to claim 2, wherein the hydrous material of the water-absorbent resin is a hydrous material of the water-absorbent resin which includes at least two layers, namely, a higher-water-content layer having a water content of 50 to 99 weight % and a lower-water-content layer having a water content of 1 to less than 50 weight %, and has a water content gradient in the hydrous material. 14. A process for production of a water-absorbing material according to claim 2, wherein the particulate agglomerates of the water-absorbing material are obtained by applying the mechanical compression force to the hydrous material and, at the same time, pulverizing it within 0.001 to 5 minutes after the fine powder of the water-absorbent resin and the aqueous liquid have come into contact with each other. 15. A process for production of a water-absorbing material according to claim 2, wherein the hydrous material of the water-absorbent resin has a temperature of 40 to 100�� C. before being pulverized after the aqueous liquid has been added thereto. 16. A process for production of a water-absorbing material according to claim 2, which further comprises a drying step (c) of further drying the particulate agglomerates of the water-absorbing material after the step (b). 17. A process for production of a water-absorbing material according to claim 16, which further comprises a pulverization step (d) of further pulverizing the particulate agglomerates of the water-absorbing material after the drying step (c), thereby obtaining a water-absorbing material including a fine powder of not larger than 150 μm in particle diameter in an amount of 0 to 20 weight % relative to the water-absorbing material. 18. A process for production of a water-absorbing material according to claim 17, which further comprises a surface-crosslinking step (e) of further crosslink-treating the surfaces or surface neighborhood portions of particles of the water-absorbing material after the pulverization step (d). 19. A process for production of a water-absorbing material according to claim 18, wherein the water-absorbing material having been surface-crosslinked in the surface-crosslinking step (e) exhibits a water absorption capacity of not less than 20 g/g under a load of 4.8 kPa (0.7 psi). 20. The process for production of a water-absorbing material according to claim 1, wherein the hydrous material is selected from the group consisting of a particulate hydrous material and sheet hydrous material. 21. The process for production of a water-absorbing material according to claim 1, wherein the hydrous material is a particulate. 22. The process for production of a water-absorbing material according to claim 1, wherein the hydrous material is a sheet having at least two layers with different water content.