Process for transporting, storing, and producing a particulate water-absorbent resin

• US 6,817,557 B2
• Filed: 01/04/2001
• Issued: 11/16/2004
• Est. Priority Date: 01/20/2000
• Status: Active Grant

• Current Assignee: Nippon Shokubai Company Limited
• Original Assignee: Nippon Shokubai Company Limited
• Inventors: Maruo, Tatsuo, Kakita, Hiroyuki, Irie, Yoshio, Hatsuda, Takumi
• Primary Examiner(s): Rosenbaum, Mark
• Application Number:
  US09/753,677
• Publication Number:
  US 20010011123A1
• Time in Patent Office: 1,412 Days
• Field of Search: 428/402, 241/30, 241/23, 241/65, 241/100, 241/25, 209/11, 528/503
• US Class Current: 241/23
• CPC Class Codes: C08J 2300/14 Water soluble or water swellable polymers, e.g. aqueous gels
• CPC Class Codes: C08J 3/12 Powdering or granulating

Abstract

The present invention provides: a process for treating a particulate water-absorbent resin, which enables to carry out pulverization stably in a process for producing a particulate water-absorbent resin, and transportation or storage of the particulate water-absorbent resin stably during or after producing the particulate water-absorbent resin, and to prevent contamination of cohered matters of the particulate water-absorbent resin; and involves no or little deterioration of properties. The process for treating a particulate water-absorbent resin is characterized by carrying out at least one selected from the group consisting of: (1) heating at least one portion of a surface getting contact with the particulate water-absorbent resin from the outside, (2) maintaining the temperature of at least one portion of a surface getting contact with the particulate water-absorbent resin at 30 to 150° C., and (3) maintaining the temperature of at least one portion of a surface getting contact with the particulate water-absorbent resin above a temperature that is lower than a temperature of the particulate water-absorbent resin by 20° C.

Claims

1. A process for storing a particulate free-flowing water-absorbent resin, which comprises a step of storing a particulate water-absorbent resin in a storage apparatus where said particulate water-absorbent resin is obtained by pulverizing a dry water-absorbent resin product,

with the process for storing being characterized by all of the steps of:

(1) heating at least one portion of a surface of said storage apparatus making contact with the particulate water-absorbent resin, where said storage apparatus is heated from the outside,

(2) maintaining the temperature of at least one portion of said surface of a storage apparatus making contact with the particulate water-absorbent resin where said surface is at a temperature of 30 to 150°

C., and

(3) maintaining the temperature of at least one portion of a surface of said storage apparatus making contact with the particulate water-absorbent resin where said surface is at a temperature above a temperature that is lower than a temperature of the particulate water-absorbent resin by 20°

C.,

when storing the particulate water-absorbent resin.

2. A process for storing a particulate water-absorbent resin according to claim 1, wherein the particulate water-absorbent resin is a surface-crosslinked particulate water-absorbent resin.

3. A process for storing a particulate water-absorbent resin according to claim 2, wherein the surface-crosslinked particulate water-absorbent resin contains at least a polyhydric alcohol.

4. A process for storing a particulate water-absorbent resin according to claim 2 wherein an absorption capacity of the surface-crosslinked particulate water-absorbent resin under a load is not less than 18 g/g.

5. A process for storing a particulate water-absorbent resin according to claim 1, wherein the particulate water-absorbent resin is a crosslinked partially-neutralized polycarboxylic acid salt.

6. A process for storing a particulate water-absorbent resin according to claim 1, wherein the dry water-absorbent resin product is a dry product obtained by drying at 160 to 250°

C.

7. A process for storing a particulate water-absorbent resin according to claim 1, wherein the particulate free-flowing water-absorbent resin has a water content of 3% to 15%.

8. A process for storing a particulate water-absorbent resin according to claim 1, wherein said particulate free-flowing water-absorbent resin has a particle diameter of not greater than 1000 μ

m.