Lithium styrene sulfonate

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.

Claims

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 m.

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 -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.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a diagram illustrating an example for determining the length of the long side and the width (height) in the present invention.

(2) FIG. 2 is a diagram illustrating an example for determining the half-value width of the main endothermic peak in the present invention.

(3) FIG. 3 is a diagram showing a microscopic photograph of lithium styrene sulfonate in a wet cake state obtained in Example 1.

(4) FIG. 4 is a diagram showing the results of differential thermogravimetric simultaneous measurement of lithium styrene sulfonate in a wet cake state obtained in Example 1.

(5) FIG. 5 is a diagram showing a powder X-ray diffraction pattern by Cu-K radiation of lithium styrene sulfonate in a wet cake state obtained in Example 1.

(6) FIG. 6 is a diagram showing the change in weight with time, when left at room temperature, of lithium styrene sulfonates in a wet cake state obtained in Example 1 and Comparative Example 1.

(7) FIG. 7 is a diagram showing the change in weight with time, when left to stand still at 40 C., of lithium styrene sulfonates in a wet cake state obtained in Example 1 and Comparative Example 1.

(8) FIG. 8 is a diagram showing a microscopic photograph of lithium styrene sulfonate in a dried cake state obtained in Example 3.

(9) FIG. 9 is a diagram showing the results of differential thermogravimetric simultaneous measurement of lithium styrene sulfonate in a dried cake state in Example 3.

(10) FIG. 10 is a diagram showing a powder X-ray diffraction pattern by Cu-K radiation of lithium styrene sulfonate in a dried cake state obtained in Example 3.

(11) FIG. 11 is a diagram showing an optical microscopic photograph of lithium styrene sulfonate obtained in Example 5.

(12) FIG. 12 is a diagram showing the results of differential thermogravimetric simultaneous measurement of lithium styrene sulfonate obtained in Example 5.

(13) FIG. 13 is a diagram showing a powder X-ray diffraction pattern by Cu-K radiation of lithium styrene sulfonate obtained in Example 5.

(14) FIG. 14 is a diagram showing a microscopic photograph of lithium styrene sulfonate in a wet cake state obtained in Comparative Example 1.

(15) FIG. 15 is a diagram showing a powder X-ray diffraction pattern by Cu-K radiation of lithium styrene sulfonate in a wet cake state obtained in Comparative Example 1.

(16) FIG. 16 is a diagram showing the results of differential thermogravimetric simultaneous measurement of lithium styrene sulfonate in a wet cake state obtained in Comparative Example 3.

(17) FIG. 17 is a diagram showing an optical microscopic photograph of lithium styrene sulfonate obtained in Comparative Example 4.

EXAMPLES

(18) Now, Examples of the present invention and Comparative Examples will be described, but the present invention is by no means limited thereto.

(19) Further, parts are by weight.

(20) Various physical properties were measured by the following methods.

(21) <Powder X-Ray Diffraction Apparatus and Conditions>

(22) Apparatus: X-ray diffraction apparatus XRD-6100 (manufactured by Shimadzu Corporation)

(23) X-ray: Cu-K

(24) Intensity: 40 kV, 30 mA

(25) Scanning speed: 2 deg./min.

(26) <Thermogravimetric-Differential Thermal Analyzer and Conditions>

(27) Apparatus: Thermogravimetric-Differential Thermal Analyzer TG/DTA6300 (manufactured by Seiko Instruments Inc.)

(28) Temperature-raising rate: 2 C./min.

(29) Measurement temperature range: 30 to 200 C.

(30) Nitrogen flow: 100 mL/min.

(31) Sample cell: made of alumina (cylindrical cell (diameter: 5.2 mm, height: 5 mm, without a lid))

(32) Amount of sample: 15 to 20 mg

(33) <Water Content Measuring Device and Conditions>

(34) Apparatus: Infrared moisture meter FD-610 (manufactured by Kett Electric Laboratory)

(35) Sample amount: 5 g

(36) Drying time: 20 min.

(37) Drying temperature: 120 C.

(38) Water content: (WW0)/W100 (W: initial sample mass, W0: dried sample mass)

(39) <Lithium Bromide Content Measuring Device and Conditions>

(40) Apparatus: ion chromatography

(41) Column: IC-Anion-PW

(42) Column temperature: 40 C.

(43) Eluent: potassium hydrogen phthalate 2 g+acetonitrile 100 mL+water (total 1,000 mL)

(44) <Polymer Content Measuring Device and Conditions>

(45) Apparatus: SEC (size exclusion chromatography)

(46) Column: TSKgel 6000+3000+guardcolumu

(47) Eluent: phosphoric acid buffer solution (pH=7)/CH.sub.3CN=9/1

(48) Detection conditions: 230 nm

(49) Column temperature: 40 C.

(50) Flow rate: 0.6 mL/min.

(51) Injection volume: 100 L

Example 1

(52) Into a reactor made of glass and equipped with a stirrer, 129 parts of lithium hydroxide monohydrate, 19 parts of lithium chloride, 0.6 part of sodium nitrite and 367 parts of pure water, were introduced, and the temperature was raised to 70 C. with stirring. Then, while stirring at a temperature of from 70 to 90 C., 431 parts of a 70 wt % -bromoethylbenzene sulfonic acid aqueous solution was dropwise added in a nitrogen atmosphere over a period of 1.5 hours. After the dropwise addition, the mixture was aged at 90 C. for 30 minutes and cooled to 50 C. At 50 C., 0.3 part of lithium styrene sulfonate was added as seed crystals, and the mixture was kept at 50 C. for 15 minutes, then cooled to 45 C. and kept at 45 C. for 15 minutes. After cooling to room temperature, the obtained slurry of lithium styrene sulfonate crystals was subjected to solid-liquid separation by centrifugal filtration at a centrifugal acceleration of about 2,500 G to obtain a compound (A) in a wet cake state of lithium styrene sulfonate crystals. The water content in the wet cake state lithium styrene sulfonate (A) was 17.8 wt %, the lithium bromide content was 0.8 wt %, and the polymer content was at most 0.01 wt %. When observed by an optical microscope, it was a mixture of plate crystals and rod-shaped crystals, and the content of plate crystals was about 25 area %. As a result of observing 50 or more plate crystals, the ratio of (long side length/width) of plate crystals was 1.4 on average, and the width of plate crystals was 80 m on average. The microscopic photograph of the wet cake state lithium styrene sulfonate (A) is shown in FIG. 3, the results of differential thermogravimetric simultaneous measurement are shown in FIG. 4, and the powder X-ray diffraction pattern by Cu-K radiation is shown in FIG. 5 and in Table 1.

(53) As the results of differential thermogravimetric simultaneous measurement, the weight reduction in a range of from 120 to 170 C. was 2.2 wt %, the temperature at the top of the main endothermic peak in a range of from 80 to 170 C. was 133 C., and the half-value width of the main endothermic peak in a range of from 80 to 170 C. was 18 C.

(54) As a result measured by a powder X-ray diffraction method, the intensity of the peak appearing at a diffraction angle of 7.9, was 4.3 times the intensity of the peak appearing at 6.8.

(55) TABLE-US-00001 TABLE 1 Diffraction angle Relative intensity (2) d (A) (I/I.sub.0) 7.9 11.2 100% 15.7 5.6 98% 25.8 3.5 45% 29.5 3.0 40% 20.0 4.4 33% 20.7 4.3 25% 26.4 3.4 25%

(56) Then, 5 g of the wet cake state lithium styrene sulfonate (A) was spread over each of two petri dishes, whereupon one was left to stand at room temperature, and the other was left to stand still in a dryer maintained at 40 C., to confirm the change in weight with time.

(57) The change in weight with time when being left to stand at room temperature is shown in FIG. 6, and the change in weight with time when being left to stand still at 40 C. is shown in FIG. 7. With the wet cake state lithium styrene sulfonate (A), reduction in weight was observed in both being left to stand at room temperature and being left to stand still at 40 C. That is, it was confirmed that the wet cake state lithium styrene sulfonate (A) can be easily dehydrated, since water content was reduced simply by being left to stand at room temperature.

Example 2

(58) A compound in a wet cake state of lithium styrene sulfonate was prepared in the same manner as in Example 1, except that an aqueous -bromoethylbenzene sulfonic acid solution was dropwise added, and after aging at 90 C. for 30 minutes, 2.1 parts of lithium styrene sulfonate was added as seed crystals at 60 C., and kept at 60 C. for 15 minutes, followed by cooling to room temperature. The water content of the wet cake state lithium styrene sulfonate was 14.3 wt %, the lithium bromide content was 0.8 wt %, and the polymer content was 0.02 wt %. When observed by an optical microscope, it was a mixture of plate crystals and rod-shaped crystals, and the content of the plate crystals was about 40 area %. As a result of observing 50 or more plate crystals, the ratio of (long side length/width) of plate crystals was 1.3 on average, and the width of plate crystals was 130 m on average. As the results of differential thermogravimetric simultaneous measurement, the weight reduction in a range of from 120 to 170 C. was 4.0 wt %, the temperature at the top of the main endothermic peak in a range of from 80 to 170 C. was 142 C., and the half-value width of the main endothermic peak in a range of from 80 to 170 C. was 14 C. The powder X-ray diffraction pattern by Cu-K radiation was the same diffraction pattern as in FIG. 5, and the intensity of the peak appearing at a diffraction angle of 7.9 was 4.1 times the intensity of the peak appearing at 6.8.

Example 3

(59) Into a reactor made of glass and equipped with a stirrer, 156 parts of lithium hydroxide monohydrate, 20 parts of lithium chloride, 0.7 part of sodium nitrite and 305 parts of pure water were introduced, and the temperature was raised to 70 C. with stirring. Then, while stirring at a temperature of from 70 to 90 C., 518 parts of a 70 wt % -bromoethylbenzene sulfonic acid aqueous solution was dropwise added in a nitrogen atmosphere over a period of 1.5 hours. After the dropwise addition, the mixture was aged at 90 C. for 50 minutes, and 2.4 parts of lithium styrene sulfonate was added as seed crystals, whereupon the mixture was kept at 90 C. for a few minutes. After cooling to room temperature, the obtained slurry of lithium styrene sulfonate crystals was subjected to solid-liquid separation by centrifugal filtration at a centrifugal acceleration of about 2,500 G to obtain a compound (B) in a dried cake state of lithium styrene sulfonate crystals. The water content of the dried cake state lithium styrene sulfonate (B) was 6.6 wt %, the lithium bromide content was 0.6 wt %, and the polymer content was at most 0.01 wt %. As shown in FIG. 8, when observed by an optical microscope, it was substantially plate crystals, and the content of the plate crystals was about 100 area %. As a result of observing 50 or more plate crystals, the ratio of (long side length/width) of plate crystals was 1.2 on average, and the width of the plate crystals was 280 m on average. The results of differential thermogravimetric simultaneous measurement of the dried cake state lithium styrene sulfonate (B) is shown in FIG. 9, and the powder X-ray diffraction pattern by Cu-K radiation is shown in FIG. 10 and in Table 2.

(60) As the results of differential thermogravimetric simultaneous measurement, the weight reduction in a range of from 120 to 170 C. was 4.3 wt %, the temperature at the top of the main endothermic peak in a range of from 80 to 170 C. was 145 C., and the half-value width of the main endothermic peak in a range of from 80 to 170 C. was 12 C.

(61) As a result measured by powder X-ray diffractometry, no peak at 6.8 was detected.

(62) TABLE-US-00002 TABLE 2 Diffraction angle Relative intensity (2) d (A) (I/I.sub.0) 7.8 11.3 100% 15.7 5.7 92% 20.7 4.3 71% 19.9 4.5 36% 13.0 6.8 22% 11.0 8.0 21% 23.7 3.7 21%

Example 4

(63) A compound in a wet cake state of lithium styrene sulfonate was prepared in the same manner as in Example 1, except that the obtained slurry of lithium styrene sulfonate was subjected to solid-liquid separation by suction filtration. The water content of the wet cake state lithium styrene sulfonate was 37.7 wt %. Further, the content of the plate crystals, the ratio of (long side length/width) of plate crystals, the width of plate crystals, and the powder X-ray diffraction pattern by Cu-K radiation of the cake, were substantially the same as in Example 1.

Example 5

(64) The dried cake state lithium styrene sulfonate (B) in Example 3, was pulverized for 15 minutes by using an agate mortar to obtain a compound of the shape shown in FIG. 11. When observed by an optical microscope, it was fine particles, and no plate crystals were observed. The results of differential thermogravimetric simultaneous measurement are shown in FIG. 12, and the powder X-ray diffraction pattern by Cu-K radiation is shown in FIG. 13 and in Table 3. As the results of differential thermogravimetric simultaneous measurement, the weight reduction in a range of from 120 to 170 C. was 3.7 wt %, the temperature at the top of the main endothermic peak in a range of from 80 to 170 C. was 126 C., and the half-value width of the main endothermic peak in a range of from 80 to 170 C. was 2.0 C. As a result measured by powder X-ray diffractometry, no peak was detected at 6.8.

(65) TABLE-US-00003 TABLE 3 Diffraction angle Relative intensity (2) d (A) (I/I.sub.0) 20.8 4.3 100% 7.9 11.1 74% 15.8 5.6 71% 20.0 4.4 52% 13.1 6.8 33% 11.2 7.9 32% 23.5 3.8 32%

Comparative Example 1

(66) A compound (C) in a wet cake state of lithium styrene sulfonate was prepared in the same manner as in Example 1 except that a -bromoethylbenzene sulfonic acid aqueous solution was dropwise added, and after aging at 90 C. for 30 minutes, the mixture was cooled to room temperature without addition of seed crystals of lithium styrene sulfonate at 50 C. The water content in the wet cake state lithium styrene sulfonate (C) was 19.1 wt %, the lithium bromide content was 0.9 wt %, and the polymer content was 0.02 wt %. As shown in FIG. 14, when observed by an optical microscope, it is rod-shaped crystals, and no plate crystals were observed. The powder X-ray diffraction pattern by Cu-K radiation of the wet cake state lithium styrene sulfonate (C) is shown in FIG. 15 and in Table 4. As a result measured by powder X-ray diffractometry, no peak was detected at 7.9.

(67) TABLE-US-00004 TABLE 4 Diffraction angle Relative intensity (2) d (A) (I/I.sub.0) 26.6 3.4 100% 19.9 4.5 63% 6.8 13.1 41% 33.3 2.7 17% 11.3 7.8 13% 16.0 5.5 13% 30.5 2.9 12%

(68) Then, 5 g of the wet cake state lithium styrene sulfonate (C) was spread over each of two petri dishes, whereupon one was left to stand at room temperature, and the other was left to stand still in a dryer maintained at 40 C. to ascertain the change in weight with time.

(69) The change in weight with time when being left at room temperature is shown in FIG. 6 and the change in weight with time when being left to stand still at 40 C. is shown in FIG. 7. The wet cake state lithium styrene sulfonate (C) was slow as compared with in Example 1, but decrease in weight i.e. dehydration was observed at 40 C. However, no substantial change in weight was observed when left to stand at room temperature.

Comparative Example 2

(70) A compound in a wet cake state of lithium styrene sulfonate was prepared in the same manner as in Example 1, except that a -bromoethylbenzene sulfonic acid aqueous solution was dropwise added, and after aging at 90 C. for 30 minutes, 0.3 part of lithium styrene sulfonate was added as seed crystals at 35 C., and the mixture was kept at 35 C. for 15 minutes and then, cooled to room temperature. The water content of the wet cake state lithium styrene sulfonate was 18.1 wt %. When observed by an optical microscope, it was rod-shaped crystals, and no plate crystals were observed. Further, the powder X-ray diffraction pattern by Cu-K radiation was the same diffraction pattern as in FIG. 15, and no peak was detected at 7.9.

Comparative Example 3

(71) Into a reactor made of glass and equipped with a stirrer, 186 parts of lithium hydroxide monohydrate, 18 parts of lithium chloride, 0.7 part of sodium nitrite and 226 parts of pure water were charged, and the temperature was raised to 70 C. with stirring. Then, while stirring at a temperature of from 70 to 90 C., 617 parts of a 70 wt % -bromoethylbenzene sulfonic acid aqueous solution was dropwise added in a nitrogen atmosphere over a period of 1.5 hours, followed by aging at 90 C. for 30 minutes. Then, without addition of seed crystals, the mixture was cooled to room temperature, and the obtained slurry of lithium styrene sulfonate crystals was subjected to solid-liquid separation by centrifugal filtration at a centrifugal acceleration of about 2,500 G, to prepare a compound in a wet cake state of lithium styrene sulfonate. The water content of the wet cake state lithium styrene sulfonate was 18.9 wt %, the lithium bromide content was 1.6 wt %, and the polymer content was 0.02 wt %. When observed by an optical microscope, it was rod-shaped crystals, and no plate crystals were observed. The results of differential thermogravimetric simultaneous measurement are shown in FIG. 16. As the results of differential thermogravimetric simultaneous measurement, the weight reduction in a range of from 120 to 170 C. was 0.1 wt %, the temperature at the top of the main endothermic peak in a range of from 80 to 170 C. was 104 C., and the half-value width of the main endothermic peak in a range of from 80 to 170 C. was 12 C. Further, the powder X-ray diffraction pattern by Cu-K radiation was the same diffraction pattern as in FIG. 15, and no peak was detected at 7.9.

Comparative Example 4

(72) Commercially available lithium styrene sulfonate (Supinoma LiSS, manufactured by Tosoh Organic Chemical Co., Ltd.) prepared by drying and pulverizing rod-shaped crystals, were fine particles as shown in FIG. 17, and no plate crystals were observed. The water content was 8.0 wt %, the lithium bromide content was 2.4 wt %, and the polymer content was 0.08 wt %. Further, as a result of differential thermogravimetric simultaneous measurement, weight reduction in a range of from 120 to 170 C. was 1.1 wt %, the temperature at the top of the main endothermic peak in a range of from 80 to 170 C. was 109 C., and the half-value width of the main endothermic peak in a range of from 80 to 170 C. was 14 C. The powder X-ray diffraction pattern by Cu-K radiation was the same diffraction pattern as in FIG. 10, and no peak was detected at 6.8.

(73) Thus, a difference in the results of differential thermogravimetric simultaneous measurement was observed between the lithium styrene sulfonate obtained by drying and pulverizing the commercially available rod-shaped crystals, and the lithium styrene sulfonate containing plate crystals of the present invention or lithium styrene sulfonate obtained by pulverizing the crystals, i.e. in the lithium styrene sulfonate of the present invention, the content of the polymer and the content of lithium bromide were lower.

Comparative Example 5

(74) The commercially available lithium styrene sulfonate in Comparative Example 4 was pulverized for 15 minutes by using an agate mortar to obtain a compound having the same shape as in FIG. 11. When observed by an optical microscope, it was fine particles, and no plate crystals were observed. As the results of differential thermogravimetric simultaneous measurement, the weight reduction in a range of from 120 to 170 C. was 0.3 wt %, the temperature at the top of the main endothermic peak in a range of from 80 to 170 C. was 104 C., and the half-value width of the main endothermic peak in a range of from 80 to 170 C. was 4.5 C. The powder X-ray diffraction pattern by Cu-K radiation was the same diffraction pattern as in FIG. 10, and no peak was detected at 6.8.

(75) In the foregoing, the present invention has been described in detail and with reference to specific embodiments thereof, and it is apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.

(76) The entire disclosure of Japanese Patent Application No. 2014-020735 filed on Feb. 5, 2014 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

(77) The lithium styrene sulfonate containing plate crystals of the present invention is useful for applications as dyeing auxiliaries, ion-exchange resins, surfactants, viscosity reducing agents, dispersing agents, hydrophilic coating agents, antistatic agents, binders for lithium secondary battery and capacitor electrode, emulsions, dispersions, etc.

REFERENCE SYMBOLS

(78) .circle-solid.: shows the results in Example 1 : shows the results in Comparative Example 1