Precipitated silica having particular morphology, grading and porosity, preparation thereof and reinforcing of polymers therewith

Patent metadata

Field	Value
Publication number	US-9359215-B2
Application number	US-92142309-A
Country	US
Kind code	B2
Filing date	Mar 9, 2009
Priority date	Mar 10, 2008
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

Precipitated silicas including clusters of large primary silica particles having at the surface thereof small primary silica particles, have a specific surface area CTAB (S CTAB ) ranging from 60 to 400 m 2 /g; a cluster average size d50, as measured by XDC grading after ultrasound deagglomeration, such that d50 (nm)>(6214/S CTAB (m 2 /g)+23; a pore volume distribution such that V (d5-d50) /V (d5-d100) >0.906−(0.0013×S CATB (m 2 /g)); and a pore size distribution such that Mode (nm)>(4166/S CTAB (m 2 /g))−9.2; such silicas are useful reinforcing fillers for polymers.

First claim

The invention claimed is:

1. A precipitated silica, comprising aggregates of precipitated silica primary particles (A) at the surface of which are grafted silica primary particles (B), wherein the silica primary particles (B) have a size smaller than that of the primary particles (A), and having:
a CTAB specific surface (S CTAB ) ranging from 60 to 400 m 2 /g;
a d50 median size of aggregates, measured by XDC particle sizing after ultrasonic deagglomeration, such that the value of d50 expressed in nanometers is greater than

(

6214
⁢

⁢

nm

m
2

/g

/

S
CTAB

)

+

23
⁢

⁢
nm

;

a pore volume distribution such that the ratio V(d5-d50)/V(d5-d100) is greater than

0.906
-

(

0.0013
⁢

⁢

1

m
2

/
g

×

S
CTAB

)

;

and
a pore size distribution such that the value of the Mode expressed in nanometers is greater than

(

4166
⁢

⁢

nm

m
2

/g

/

S
CTAB

)

-

9.2
⁢

⁢
nm

;

wherein S CTAB is the value of the CTAB specific surface expressed in m 2 /g.

2. The precipitated silica as defined by claim 1 , comprising aggregates of large silica primary particles, at the surface of which are small silica primary particles, the number median diameter of the large primary particles being at least 12 nm and the number median diameter of the small primary particles ranging from 2 to 8 nm.

3. The precipitated silica as defined by claim 1 , having a pore volume distribution such that V (d5-d50) /V (d5-d100) >0.71.

4. The precipitated silica as defined by claim 1 , having a CTAB specific surface (S CTAB ) ranging from 80 to 300 m 2 /g.

5. The precipitated silica as defined by claim 1 , having a BET specific surface (S BET ) ranging from 60 to 500 m 2 /g.

6. The precipitated silica as defined by claim 1 , having a CTAB specific surface (S CTAB ) and a BET specific surface (S BET ) such that the S BET /S CTAB ratio ranges from 1.0 to 1.5.

7. The precipitated silica as defined by claim 1 , having a median diameter (D 5M ), after ultrasonic deagglomeration, of less than 6.0 μm.

8. The precipitated silica as defined by claim 1 , in the form of substantially spherical beads, optionally having a mean size of at least 80 μm.

9. The precipitated silica as defined by claim 1 , in the form of a powder, optionally having a mean size of at least 3 μm.

10. The precipitated silica as defined by claim 1 , in the form of granules, optionally having a size of at least 1 mm.

11. The precipitated silica as defined by claim 1 , wherein the proportion of isolated small primary particles (B), aggregated or not aggregated together, is less than 10% by number.

12. The precipitated silica as defined by claim 1 , having a parameter C, measured by small angle X-ray scattering (SAXS), such that C/S CTAB is greater than 0.001 g/m 2 , wherein S CTAB is the value of the CTAB specific surface expressed in m 2 /g.

Assignees

• Allain Emmanuelle
• Hernandez Julien
• Ventelon Lionel
• Guy Laurent
• Airiau Marc
• Rhodia Operations

Inventors

• Allain Emmanuelle
• Hernandez Julien
• Ventelon Lionel
• Guy Laurent
• Airiau Marc

Classifications

• C01B33/12

  Silica; Hydrates thereof, e.g. lepidoic silicic acid · CPC title

• C01B33/193 Primary

  of aqueous solutions of silicates · CPC title

• Y10T428/2982

  Particulate matter [e.g., sphere, flake, etc.] · CPC title