Mesoporous silica, process for the preparation of the same, and use thereof

1. Mesoporous silica characterized by having an average pore diameter in the mesopore region of from 1.5 to 10 nm, a nitrogen adsorption specific surface area determined by the BET method of from 500 to 1400 m 2 /g and a monolayer adsorption of water at 25° C. of 1.7 H 2 O molecules/nm 2 specific surface area or more.

2. A process for synthesizing mesoporous silica comprising the steps of:

mixing and reacting active silica with a neutral template to synthesize an active silica/neutral template complex; and

bringing the active silica/neutral template complex into contact with a solvent to remove the neutral template from said complex;

wherein said mesoporous silica is characterized by having a monolayer adsorption of water at 25° C. of 1.7 H 2 O molecules/nm 2 specific surface area or more.

3. The process for synthesizing mesoporous silica as claimed in claim 2 , wherein said neutral template is an amine represented by the following structural formula (1):

RNH 2   (1)

wherein R represents an alkyl group having 8 to 20 carbon atoms.

4. The process for synthesizing mesoporous silica as claimed in claim 2 , wherein said neutral template is a nonionic surfactant represented by the following structural formula (2):

R(OCH 2 CH 2 ) n OH  (2)

wherein R represents an alkyl group having 12 to 20 carbon atoms; and n is from 2 to 30.

5. The process for synthesizing mesoporous silica as claimed in claim 2 , wherein said neutral template is an amine oxide represented by the following structural formula (3):

R(CH 3 ) 2 NO  (3)

wherein R represents an alkyl group having 8 to 20 carbon atoms.

6. The process as claimed in claim 2 , wherein said solvent to be used in removing the neutral template is an alcohol.

7. An ink absorbent comprising a mesoporous silica synthesized by using a template, wherein said mesoporous silica is the mesoporous silica as claimed in claim 1 .

8. An ink absorbent slurry composed of the ink absorbent as claimed in claim 7 and a solvent.

9. A recording sheet characterized by containing the ink absorbent as claimed in claim 7 .

10. An ink absorbent comprising the mesoporous silica as claimed in claim 1 .

11. An ink absorbent comprising the mesoporous silica of claim 1 , which is synthesized by a process comprising mixing and reacting a silica source with a template to synthesize a silica/template complex.

12. The ink absorbent as claimed in claim 11 , wherein said template is a neutral template and said silica/template complex is a silica/neutral template complex.

13. The ink absorbent as claimed in claim 12 , wherein said process further comprising removing said neutral template from said silica/neutral template complex.

14. The ink absorbent as claimed in claim 11 , wherein said silica is an active silica.

15. The ink absorbent as claimed in claim 12 , wherein said neutral template is an amine represented by the following structural formula (1):

RNH 2   (1)

wherein R represents an alkyl group having 8 to 20 carbon atoms.

16. The ink absorbent as claimed in claim 12 , wherein said neutral template is a nonionic surfactant represented by the following structural formula (2):

R(OCH 2 CH 2 ) n OH  (2)

wherein R represents an alkyl group having 12 to 20 carbon atoms; and n is from 2 to 30.

17. The ink absorbent as claimed in claim 12 , wherein said neutral template is an amine oxide represented by the following structural formula (3):

R(CH 3 )NO  (3)

wherein R represents an alkyl group having 8 to 20 carbon atoms.

18. The ink absorbent as claimed in claim 13 , wherein said neutral template-removing step is carried out by bringing said silica/neutral template complex into contact with a solvent.

19. The ink absorbent as claimed in claim 18 , wherein said solvent comprises an alcohol.

20. An ink absorbent slurry comprising the ink absorbent as claimed in claim 10 and a solvent.

21. An ink absorbent slurry comprising the ink absorbent as claimed in claim 11 and a solvent.

22. A recording sheet containing the ink absorbent as claimed in claim 10 .

23. A recording sheet containing the ink absorbent as claimed in claim 11 .

24. An ink absorbent slurry comprising the ink absorbent as claimed in claim 14 and a solvent.

25. A recording sheet containing the ink absorbent as claimed in claim 14 .

26. An ink absorbent comprising mesoporous silica synthesized by the process of claim 2 .

27. An ink absorbent slurry comprising the ink absorbent of claim 26 and a solvent.

28. A recording sheet comprising the ink absorbent of claim 26 .

29. An ink absorbent slurry comprising the ink absorbent of claim 12 and a solvent.

30. A recording sheet containing the ink absorbent of claim 12 .

31. An ink absorbent slurry comprising the ink absorbent of claim 13 and a solvent.

32. A recording sheet containing the ink absorbent of claim 13 .

33. An ink absorbent slurry comprising the ink absorbent of claim 15 and a solvent.

34. A recording sheet containing the ink absorbent of claim 15 .

35. An ink absorbent slurry comprising the ink absorbent of claim 16 a solvent.

36. A recording sheet containing the ink absorbent of claim 16 .

37. An ink absorbent slurry comprising the ink absorbent of claim 17 and a solvent.

38. A recording sheet containing the ink absorbent of claim 17 .

39. An ink absorbent slurry comprising the ink absorbent of claim 18 and a solvent.

40. A recording sheet containing the ink absorbent of claim 18 .

41. An ink absorbent slurry comprising the ink absorbent of claim 19 and a solvent.

42. A recording sheet containing the ink absorbent of claim 19 .