Disclosed is a method for producing a water absorbent resin, by which a surface-crosslinked water absorbent resin having excellent physical properties can be efficiently obtained at low cost, while assuring high productivity. When the production scale is increased to a continuous production at 1 t/h
Disclosed is a method for producing a water absorbent resin, by which a surface-crosslinked water absorbent resin having excellent physical properties can be efficiently obtained at low cost, while assuring high productivity. When the production scale is increased to a continuous production at 1 t/hr or more, the physical properties are improved and stabilized (for example, standard deviation of the physical properties is reduced) by a surface-crosslinking treatment, and the absorption against pressure (AAP) and liquid permeability (SFC) are further improved. Specifically disclosed is a method for producing a water absorbent resin, which is characterized in that the stirring shaft of the continuous mixing apparatus for the surface-crosslinking agent is heated during the mixing step of the surface-crosslinking agent or that the continuous mixing apparatus for the surface-crosslinking agent is operated at a pressure that is reduced relative to the ambient pressure and a gas flow is passed through the mixing apparatus during the mixing of the surface-crosslinking agent so that the gas flow in the mixing apparatus is 40° C. or more (when defined with respect to the gas temperature at the exit).
대표청구항▼
1. A method for producing a polyacrylic acid (salt)-type water absorbent resin comprising steps of: preparing an aqueous monomer solution of an acrylic acid (salt),continuously polymerizing the aqueous monomer solution into a hydrous gel-like crosslinked polymer,finely shredding the hydrous gel-like
1. A method for producing a polyacrylic acid (salt)-type water absorbent resin comprising steps of: preparing an aqueous monomer solution of an acrylic acid (salt),continuously polymerizing the aqueous monomer solution into a hydrous gel-like crosslinked polymer,finely shredding the hydrous gel-like crosslinked polymer during or after polymerization,drying the obtained particulate hydrous gel-like crosslinked polymer to obtain a dried water absorbent resin powder,adding a surface-crosslinking agent to the dried water absorbent resin powder with a continuous mixing apparatus, wherein the pressure inside of the continuous mixing apparatus is a reduced pressure greater than 0 kPa and is 10 kPa or lower than atmospheric pressure, andcarrying out reaction of the mixture, whereina stifling shaft of the continuous mixing apparatus for the surface-crosslinking agent is heated in the step of mixing the surface-crosslinking agent. 2. A method for producing a polyacrylic acid (salt)-type water absorbent resin comprising steps of: preparing an aqueous monomer solution of an acrylic acid (salt),continuously polymerizing the aqueous monomer solution into a hydrous gel-like crosslinked polymer,finely shredding the hydrous gel-like crosslinked polymer during or after polymerization,drying the obtained particulate hydrous gel-like crosslinked polymer to obtain a dried water absorbent resin powder,adding a surface-crosslinking agent to the dried water absorbent resin powder with a continuous mixing apparatus, andcarrying out reaction of the mixture, whereinthe continuous mixing apparatus for the surface-crosslinking agent is operated at below ambient pressure and at a gas current of at least 40° C. to adjust the outlet gas temperature of the gas current in the mixing apparatus during mixing the surface-crosslinking agent, wherein the pressure inside of the continuous mixing apparatus is a reduced pressure greater than 0 kPa and is 10 kPa or lower than atmospheric pressure. 3. The production method according to claim 1 or 2, wherein the stirring shaft of the continuous mixing apparatus for the surface-crosslinking agent is so heated as to be at a higher temperature than the inner wall temperature of the continuous mixing apparatus. 4. The production method according to claim 1 or 2, wherein the pressure of the inside of the continuous mixing apparatus for surface-crosslinking agent is reduced. 5. The production method according to claim 1 or 2, wherein 50 to 100% in the inner surface area of the continuous mixing apparatus is of a metal. 6. The production method according to claim 1 or 2, wherein the inner face of the inside of the continuous mixing apparatus for the surface-crosslinking agent is of a stainless steel with a surface roughness (Rz) of 800 nm or lower. 7. The production method according to claim 1 or 2, wherein the reaction step for the mixture is carried out at 150° C. to 250° C. 8. The production method according to claim 1 or 2, wherein the water absorbent resin powder is pneumatically transported by using compressed air with a dew point of −5° C. to −100° C. 9. The production method according to claim 1 or 2, wherein the mixing apparatus is a hoe type blender. 10. The production method according to claim 1 or 2, wherein the temperature of the mixture is 50 to 95° C. until the mixture flows to the reaction step after the surface-crosslinking agent is mixed. 11. The production method according to claim 1 or 2, wherein the reaction step of the mixture has two or more lines in the polymerization step. 12. The production method according to claim 1 or 2, wherein the average residence time of the water absorbent resin in the continuous mixing apparatus is within 1 minute. 13. The production method according to claim 1 or 2, wherein the temperature of the mixture is increased by 0.5° C. or more by continuously mixing the crosslinking agent to the dried water absorbent resin powder. 14. The production method according to claim 1 or 2, wherein the water absorbent resin has 20 g/g or higher of water absorption against pressure (AAP) for an aqueous 0.9 wt. % sodium chloride solution at a pressure of 4.8 kPa, 1 (×10−7·cm3·s·g−1) or higher of saline flow conductivity of 0.69 wt. % physiological saline solution (SFC), and 20 g/g or higher of water absorption under no pressure (CRC).
연구과제 타임라인
LOADING...
LOADING...
LOADING...
LOADING...
LOADING...
이 특허에 인용된 특허 (49)
Goldman Stephen Allen (Wyoming OH) Haynes Nancy Ann (Okeana OH) Mansfield Todd Leon (Cincinnati OH) Plischke Manfred (Steinbach DEX) Retzsch Herbert Louis (Cincinnati OH) Walker Trevor (Cincinnati OH, Absorbent members for body fluids having good wet integrity and relatively high concentrations of hydrogel-forming absor.
Chmelir Miroslav (Krefeld DEX) Pauen Josef (Willich DEX), Apparatus for the continuous production of polymers and copolymers of water-soluble monomers.
Dahmen Kurt (Mnchengladbach-Rheydt DEX) Mertens Richard (Krefeld DEX), Aqueous-liquid and blood-absorbing powdery reticulated polymers, process for producing the same and their use as absorbe.
Riegel, Ulrich; Weismantel, Matthias; Frenz, Volker; Daniel, Thomas; Engelhardt, Fritz, Method for the secondary cross-linking of hydrogels with 2-oxotetrahydro-1,3-oxazines.
Riegel, Ulrich; Weismantel, Matthias; Frenz, Volker; Daniel, Thomas; Engelhardt, Fritz, Method for the secondary cross-linking of hydrogels with N-acyl-2-oxazolidinones.
Dairoku,Yorimichi; Adachi,Yoshifumi; Nogi,Kozo; Inoue,Hiroki; Wada,Katsuyuki; Irie,Yoshio, Particulate water absorbent agent and production method thereof, and water absorbent article.
Brehm Helmut (Krefeld DEX) Hartan Hans-Georg (Kevelaer DEX), Powdery polymers capable of absorbing aqueous liquids, a process for their production and their use as absorbents.
Mertens, Richard; Harren, Jorg, Powdery, cross-linked polymers which absorb aqueous liquids and blood, method for the production thereof and their use.
Rudiger Funk DE; Volker Frenz DE; Ulrich Riegel DE; Matthias Weismantel DE; Fritz Engelhardt ; Thomas Daniel, Process for crosslinking hydrogels with bis- and poly-2- oxazolidinones.
Hatsuda,Takumi; Irie,Yoshio; Nakamura,Masatoshi; Wada,Katsuyuki; Fujino,Shinichi; Kimura,Kazuki; Ishizaki,Kunihiko, Water-absorbent resin and production process therefor.
Dairoku,Yorimichi; Irie,Yoshio; Fujino,Shinichi; Fujita,Yasuhiro; Azumi,Takashi; Ishizaki,Kunihiko, Water-absorbent resin, hydropolymer, process for producing them, and uses of them.
Nakashima,Yasuhisa; Ikeuchi,Hiroyuki; Fujita,Yasuhiro; Nagasawa,Makoto; Sakamoto,Shigeru; Dairoku,Yorimichi; Wada,Katsuyuki; Fujino,Shinichi; Kitayama,Toshimasa; Hitomi,Kazuhisa, Water-absorbing agent and production process therefor, and sanitary material.
Kazuhisa Hitomi JP; Yuji Yamamoto JP; Shigenori Kirimura JP; Nobuyuki Harada JP, Water-absorbing composition and production process for water-absorbing agent.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.