Silica suspension in an organic solvent and method for its manufacture

A suspension of silica particles comprising:

• a liquid [liquid (L)] selected from the group consisting of the linear or branched, saturated or unsaturated, aliphatic and cycloaliphatic hydrocarbons having from 6 to 30 carbon atoms and of the aromatic hydrocarbons having from 6 to 10 carbon atoms,
• silica particles, and
• at least one compound [compound (S)] selected from the group consisting of:
• i. the acid phosphate esters of formula (I)
• P(O)((OCH2CH2)nOR)a(OM)b (I)
• wherein:
• R represents a linear or branched, saturated or unsaturated, aliphatic hydrocarbon group having from 1 to 24 carbon atoms or an aromatic hydrocarbon having from 6 to 24 carbon atoms;
• either M is H and n is an integer from 4 to 10, or M is Na or K and n is an integer from 0 to 12;
• a is an integer equal to 1 or 2, and b is 3−a;
• ii. the amines of formula (II)
• NR1R2R3 (II)
• wherein each R1, R2, R3 is independently selected from the group consisting of H, linear or branched, saturated or unsaturated, aliphatic hydrocarbon groups having from 1 to 24 carbon atoms, and —(CH2CH2O)n1H, wherein each n1 is an integer from 1 to 16, with the proviso that at least one of R1, R2 and R3 is —(CH2CH2O)n1H with n1 as previously defined;
• and
• iii. the succinates of formula (III):
• R4OC(O)CH2CHM1C(O)OR5 (III)
• wherein R4 and R5 are independently selected from the group consisting of the linear or branched, saturated or unsaturated, aliphatic hydrocarbon groups having from 1 to 24 carbon atoms;
• and
• iv. functionalised oligomers comprising recurring units deriving from at least one conjugated diene monomer and at least one alkoxysilyl functional group,
• characterised in that said compound (S) is miscible in liquid (L) in the temperature range from 20° C. to 50° C.