Lithium styrene sulfonate

Patent metadata

Field	Value
Publication number	US-10011563-B2
Application number	US-201515116345-A
Country	US
Kind code	B2
Filing date	Feb 4, 2015
Priority date	Feb 5, 2014
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

To provide a novel lithium styrene sulfonate which is capable of solving a problem of an increase of the production cost due to drying under atmospheric pressure or reduced pressure at a temperature of at least 40° C. and a problem of polymerization of lithium styrene sulfonate. The lithium styrene sulfonate is characterized in that when measured by using a Thermogravimetric-Differential Thermal Analyzer under measuring condition of heating at a temperature raising rate of 2° C./min in a nitrogen stream, the temperature at the top of the main endothermic peak in a range of from 80 to 170° C., is at least 120° C.

First claim

The invention claimed is:

1. Plate crystals of lithium styrene sulfonate wherein when measured by using a Thermogravimetric-Differential Thermal Analyzer under measuring condition of heating at a temperature raising rate of 2° C./min in a nitrogen stream, the temperature at the top of the main endothermic peak in a range of from 80 to 170° C., is at least 120° C.

2. The plate crystals of lithium styrene sulfonate according to claim 1 , wherein when measured by using a Thermogravimetric-Differential Thermal Analyzer under measuring condition of heating at a temperature raising rate of 2° C./min in a nitrogen stream, the weight reduction in a range of from 120 to 170° C., is at least 2.2 wt %, and the water content is from 4.0 to 50.0 wt %.

3. The plate crystals of lithium styrene sulfonate according to claim 1 , wherein the content of plate crystals is at least 10 area % and at most 100 area %.

4. The plate crystals of lithium styrene sulfonate according to claim 1 , wherein the ratio of (long side length/width) of the plate crystals is at most 3.0.

5. The plate crystals of lithium styrene sulfonate according to claim 1 , wherein the width of the plate crystals is at least 10 μm.

6. The plate crystals of lithium styrene sulfonate according to claim 1 , wherein when measured by a powder X-ray diffraction method by using Cu-Ka radiation, at least the intensity of a peak appearing at a diffraction angle of 7.9° is stronger than the intensity of a peak appearing at a diffraction angle of 6.8°.

7. The plate crystals of lithium styrene sulfonate according to claim 1 , wherein when measured by using a Thermogravimetric-Differential Thermal Analyzer under measuring condition of heating at a temperature raising rate of 2° C./min in a nitrogen stream, the half-value width of the main endothermic peak in a range of from 80 to 170° C., is at most 3.5° C.

8. The plate crystals of lithium styrene sulfonate according to claim 1 , wherein the content of the polymer is at most 0.05 wt %.

9. The plate crystals of lithium styrene sulfonate according to claim 1 , wherein the content of lithium bromide is at most 1.5 wt %.

10. A method for producing the plate crystals of lithium styrene sulfonate as defined in claim 1 , wherein reacting an aqueous lithium hydroxide solution and an aqueous β-bromoethylbenzene sulfonic acid solution at a temperature of at least 60° C., followed by adding seed crystals of lithium styrene sultanate at a temperature of at least 40° C.

Assignees

• Tosoh Corp

Inventors

• Shiraishi Chikara
• Kasahara Senshi

Classifications

• C07C309/29 Primary

  of non-condensed six-membered aromatic rings · CPC title

• C07B2200/13

  Crystalline forms, e.g. polymorphs · CPC title

• C07C303/32

  of salts of sulfonic acids · CPC title