Wettable silylated metal oxides

摘要

Production of partially hydrophobized metal oxide involves silylating the metal oxide with an organosilane and/or organosiloxane in an amount of 0.015-0.15 mmole/g per 100 m2/g of BET surface area. Production of partially hydrophobized metal oxide involves silylating the metal oxide with an organosilane of formula (I) and/or an organosiloxane comprising at least two units of formula (IIa)-(IIc) in an amount of 0.015-0.15 mmole/g per 100 m2/g of BET surface area: (R1nSiX(4-)) (I) (R13SiO(1/2)) (IIa) (R12SiO(2/2)) (IIb) (R1SiO(3/2)) (IIc) n = 1-3; R1 = optionally halogenated 1-24C hydrocarbyl; H = halo, nitrogen residue (not defined), OR2, OCOR2 or O(CH2)xOR2; R2 = H or 1-12C hydrocarbyl; x = 1-3. Independent claims are also included for: (1) A partially hydrophobized silica with a water contact angle in air of less than 180 degrees, a surface coverage with organosilyl groups of 1-50%, a surface silanol group density of 0.9-1.7 groups/nm2, a carbon content of 0.1-20 wt.% and a methanol number of less than 30; (2) An additive for controlling the rheology of liquid and powder systems, comprising silica as above; (3) A toner or developer comprising silica as above; (4) An emulsion comprising silica as above.