Silica with homogeneous layer of silylating agent

A process for preparing silylated silica particles, comprising silylating silica particles with an organosiloxane composed of A units of the formula (I)

• (R13SiO1/2) (I)
• and B units of the formulae (IIa-c)
• (R12SiO2/2), and/or (IIa)
• (R1SiO3/2), and/or (IIb)
• (SiO4/2) (IIc),
• said organosiloxane optionally bearing 1 or 2 attached groups X bonded to Si atoms where X is OR, halogen, or acetoxy, where R is H or a monovalent C1-4 alkyl radical,
• R1 is identical or different a saturated or unsaturated, monovalent, or halogenated C1-18 hydrocarbon radical,
• the number of groups ≡SiX or ═SiX2 present in said organosiloxane defined as C, wherein A, and
• B, and C obey the relationships 750<B<10,000,
• B≧A+C.

A process for preparing silylated silica particles, comprising silylating silica particles with an organosiloxane composed of A units of the formula (I)

• (R13SiO1/2) (I)
• and B units of the formulae (IIa-c)
• (R12SiO2/2), and/or (IIa)
• (R1SiO3/2), and/or (IIb)
• (SiO4/2) (IIc)
• said organosiloxane optionally bearing 1 or 2 attached groups X bonded to Si atoms where X is OR, halogen, or acetoxy, where R is H or a monovalent C1-4 alkyl radical,
• R1 is identical or different a saturated or unsaturated, monovalent, or halogenated C1-18 hydrocarbon radical,
• the number of groups ≡SiX or ═SiX2 present in said organosiloxane defined as C, wherein A, B, and C obey the relationships 1≦B≦100 or 750<B<10,000,
• B≧A+C,
• and, when A+C=0, 10≦B≦100 or 750<B<10,000, and wherein at least one B unit selected from the group consisting of (IIb) and (IIc) is present.