Precipitated silicic acids, process for their preparation and use thereof

1 . Precipitated silicas, having:

a N-cetyl-N,N,N-trimethylammonium bromide (CTAB) surface area ≤115 m 2 /g,

a dioctyl adipate (DOA) absorption ≥130 ml/(100 g),

a RoTap for >300 μm of ≥86%,

a silanol group density ≥5.4 OH/nm 2 , and

a pore volume distribution of V (d5−d50)/V (d5−d100)<0.66.

2 . The precipitated silicas according to claim 1 , having a CTAB surface area ≤90 m 2 /g.

3 . The precipitated silicas according to claim 1 , having a PV value at 0.0042 MPa-414 MPa, and 140°, in the range of 1.00-3.00 ml/g.

4 . The precipitated silicas according to claim 1 , having a bulk density of at least 180 g/l.

5 . The precipitated silicas according to claim 1 , having a grain length ≥1 mm.

6 . A method of producing the precipitated silicas according to claim 1 , comprising:

a) forming an aqueous solution of an organic and/or inorganic salt and/or an alkali metal or alkaline earth metal silicate and/or an organic and/or inorganic base with a pH ≥9;

b) adding a waterglass and an acidifying agent simultaneously into the aqueous solution while stirring at 80-98° C. for 60-120 minutes;

c) adding acid only in a smaller amount than in b) in order to attain a mixture with a pH (measured at 60° C.) of 9.0-10.0;

d) stirring the mixture at a temperature >85° C. for 45 min to 200 min, without adding further reactants;

e) adding sulfuric acid for acidification to a pH of about 3.5-4.5 € when measured at 60° C.) to obtain a mixture of precipitated silica;

f) filtering the precipitated silica from the mixture,

g) washing the filtered precipitated silica;

h) drying the washed precipitated silica to a drying loss of <8%, and

i) forming a pellet of the dried precipitated silica.

7 . A rubber mixture comprising:

(A) a rubber or a mixture of rubbers; and

(B) at least one precipitated silica according to claim 1 .

8 . A method of producing the rubber mixture according to claim 7 , comprising:

mixing the rubber or the mixture of rubbers, the at least one precipitated silica, and optionally further rubber auxiliaries in a mixing unit.

9 . A material comprising the rubber mixture of claim 7 , wherein the material is selected from the group consisting of tires, cable sheaths, hoses, drive belts, conveyor belts, roll coverings, footwear soles, gasket elements and damping elements.