Patent ID: 7563827

Claim:
A process for producing a modified metal oxide sol, comprising: producing a stannic oxide aqueous sol comprising stannic oxide particles, wherein sizes of the stannic oxide particles are from 4 to 50 nm, and a SnO 2 concentration of from 0.5 to 50 wt %; hydrothermally treating the stannic oxide aqueous sol at a temperature of from 100 to 300° C.; mixing the hydrothermally treated stannic oxide aqueous sol with an aqueous solution of an oxyzirconium salt having a concentration of from 0.5 to 50 wt % as calculated as ZrO 2 ; heating the obtained mixed liquid at a temperature of from 60 to 100° C. for from 0.1 to 50 hours to prepare a stannic oxide-zirconium oxide composite aqueous sol having particle sizes of from 4 to 50 nm; mixing the heated stannic oxide-zirconium oxide composite aqueous sol with an aqueous medium comprising Sb 2 O 5 colloidal particles comprising an alkylamine, an oligomer thereof or a mixture thereof; aging the aqueous mixture of the stannic oxide-zirconium oxide composite aqueous sol and aqueous medium comprising Sb 2 O 5 colloidal particles comprising an alkylamine at a temperature of from 20 to 300° C. for from 0.1 to 50 hours; and contacting the aged aqueous mixture with an anion exchanger to remove anions present in the sol; wherein a weight ratio of ZrO 2 /SnO 2 in the stannic oxide-zirconium oxide composite aqueous sol is from 0.05 to 0.50, an alkylamine/Sb 2 O 5 molar ratio in the Sb 2 O 5 colloidal particles comprising an alkylamine is from 0.02 to 4.00, and a weight ratio of Sb 2 O 5 /SnO 2 +ZrO 2 ) in the aqueous mixture of the stannic oxide-zirconium oxide composite aqueous sol and aqueous medium comprising Sb 2 O 5 colloidal particles comprising an alkylamine is from 0.01 to 0.50, calculated as metal oxides.