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Patent Searching and Data


Title:
SILICA
Document Type and Number:
Japanese Patent JPH01111710
Kind Code:
A
Abstract:

PURPOSE: To produce an amorphous silica suitable for use as an abrasive of a transparent toothpaste composition by specifying a surface area, particle size, abrasion value, pore diameter and a transmittance at a specified refractive index.

CONSTITUTION: In the amorphous silica, BET surface area is about 420-550 m2/g, wt. average particle size is about 5-20 μ, perspex abrasion value is about 15-28, preferably about 15-25, average pore diameter is about 3.0-8.0 nm, a transmittance in the RI range of 1.444-1.460 is ≥70%. In the production of the silica, a sodium silicate having a ratio of silica and Na2O of (3.2-3.4):1 is allowed to react with a mineral acid, and concn. and amount of these reactants are controlled to adjust pH to about 10-10.5. Then an aq. electrolyte containing a cation such as Na or K and an anion such as Cl or SO4 are allowed to exist, and the weight ratio of the electrolyte to the silica is kept in about 0.4-1.2, and a sedimentation reaction is executed at about 45-55°C. Then the mineral acid is added to keep a reaction system acidic and a formed silica is separated and washed.


Inventors:
DEREKU ARUDOKUROFUTO
JIYON ROBAATO NIYUUTON
PIITAA UIRIAMU SUTANIA
Application Number:
JP23143188A
Publication Date:
April 28, 1989
Filing Date:
September 14, 1988
Export Citation:
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Assignee:
UNILEVER NV
International Classes:
A61K8/00; A61K8/25; C01B33/187; A61Q11/00; C01B33/12; C01B33/18; C01B33/193; (IPC1-7): A61K7/16; C01B33/187
Attorney, Agent or Firm:
Yuzo Yamazaki (3 others)