| 摘要 |
An Abrasive compn. conyains an amorphous silica, pptd. by acidulation of a soln. of an alkaline earth metal silicate in soft water, which is intimately reacted with an alkaline earth, pref Ca, Sr or Mg, partic, Ca, salt to give 10-300, pref. 10-100, ppm. alkaline earth ions. The amorphous silica has a radioactive abrasion value > 40, a compressed mass of 0.24-0.55 g/ml an oil absorption of 70-95 cm3/100g, a BET specific surface of 100-250 m2/g, and a heat loss of 4-6 %. This silica is used in dentifrice pastes.
|
