POLYACRYLIC ACID (SALT), POLYACRYLIC ACID (SALT)-BASED WATER-ABSORBING RESIN, AND PROCESS FOR PRODUCING SAME

• US 20170158791A1
• Filed: 02/23/2017
• Published: 06/08/2017
• Est. Priority Date: 04/26/2010
• Status: Active Grant

• Current Assignee: Nippon Shokubai Company Limited
• Original Assignee: Nippon Shokubai Company Limited
• Inventors: MATSUMOTO, Satoshi, MIURA, Yuki, ISHIZAKI, Kunihiko, SAKAMOTO, Shigeru
• Granted Patent: US 10,640,588 B2
• Time in Patent Office: Days
• CPC Class Codes: B01J 20/261 obtained by reactions only involving carbon to carbon unsaturated bonds macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds per se C08F
• CPC Class Codes: B01J 20/267 Cross-linked polymers
• CPC Class Codes: B01J 20/3085 Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
• CPC Class Codes: C08F 120/06 Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• CPC Class Codes: C08F 20/06 Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• CPC Class Codes: C08F 220/06 Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof

Abstract

Disclosed are a polyacrylate (salt) and a polyacrylate (salt) water-absorbent resin containing a tracer which can be verified back to the manufacturing process of the water-absorbent resin when dealing with various problems with the water-absorbent resin which can occur from the manufacturing process of the water-resistant resin, during the use thereof by a consumer, up until the disposal thereof. The disclosed polyacrylate (salt) and the polyacrylate (salt) water-absorbent resin have a carbon stable isotope ratio (δ¹³C) of at least −20‰ when measured by accelerator mass spectrometry.

Claims

1. A method for producing a polyacrylic acid (salt)-type water-absorbing resin selected from a water-soluble polyacrylic acid (salt) or a polyacrylic acid (salt)-type water-absorbing resin comprising a polymerization step for a water-soluble unsaturated monomer and a drying step for the obtained water containing gel-like crosslinked polymer, wherein

the polymerization step is for polymerizing acrylic acid with a carbon stable isotope ratio (δ

¹³C) 20‰

or higher as the water-soluble unsaturated monomer.

2. The method for producing a polyacrylic acid (salt)-type water absorbing resin according to claim 1, wherein a raw material main component of the acrylic acid is obtained from biomass derived from a C4 plant.

3. The method for producing a polyacrylic acid (salt)-type water-absorbing main according to claim 1, wherein the carbon stable isotope ratio (δ

¹³C) of acrylic acid in the polymerization step is changed depending on one of a production line, production time, and a product lot number.

4. The method for producing a polyacrylic acid (salt)-type water-absorbing resin according to claim 1, wherein the water-soluble unsaturated monomer is obtained by mixing acrylic acid having different carbon stable isotope ratios (δ

¹³C).

5. The method for producing a polyacrylic acid (salt)-type water-absorbing resin according to claim 1, wherein the dried material obtained in the drying step is surface-crosslinked with an organic surface-crosslinking agent after the drying step and, if necessary, coated with a surface treatment agent selected from a polyvalent metal salt, a polyamine polymer, and water insoluble inorganic particles after the drying step.

6. The method for producing a polyacrylic acid (salt)-type water-absorbing resin according to claim 1, wherein the water-soluble unsaturated monomer further satisfies one or more of the following:

the content of 3-hydroxypropionic acid in 1000 ppm or less;

the content of the polymerization inhibitor is 1 to 160 ppm;

the content of Fe is 0 to 2 ppm; and

the content of mono- or di-hydroxyacetone is 0 to 10 ppm or less.

7. The method for producing a polyacrylic acid (salt)-type water-absorbing resin according to claim 1, wherein a drying temperature at the drying step is 50 to 300°

C. (drying is conducted under reduced pressure if the drying temperature is 100°

C. or lower) and a drying time at the drying step is 10 to 120 minutes.

8. The method for producing a polyacrylic acid (salt)-type water-absorbing resin according to claim 1, wherein a fine powder recycle step is employed besides the above steps.