Patent ID: 7910216

Claim:
A process for forming a composition comprising organosilsesquioxanes, the process comprising the following steps: (1) partially hydrolysing hydrolysable inorganic monomer precursors comprising at least 50 mole % of first hydrolysable inorganic monomer precursors having the formula RSiY 3 , in which R is an organic group which is stable to hydrolyis and which is the same or different to each other R group, the R—Si bond is a non-hydrolysable bond, and each Y group is the same as or different to each other Y group and is selected from chemically-reactive groups such that each Si—Y bond is hydrolysable to form a Si—OH bond, to form inorganic monomers and allowing partial condensation of the inorganic monomers to form a liquid composition comprising inorganic oligomers, wherein a mineral acid catalyst is used to initiate hydrolysis of the hydrolysable inorganic monomer precursors, wherein an amount of water is added to the hydrolysable monomer precursors so as to achieve hydrolysis of one or at most two of the hydrolysable bonds present in the first hydrolysable monomer precursors; (2) prior to complete condensation of the inorganic monomers, quenching the liquid composition with an amount of water which, in combination with the water used in step (1) and any water liberated by condensation of the inorganic monomers in step (1), is in excess of the stoichiometric amount of water required to achieve complete hydrolysis of all the hydrolysable inorganic monomer precursors present, so as to fully hydrolyse the hydrolysable monomer precursors present and favor further condensation; and (3) drying the composition to remove essentially all free water and any volatiles and form a dried, essentially water- and volatiles-free composition that is a liquid, wherein, when step (1) comprises partially hydrolysing different hydrolysable inorganic monomer precursors, said different hydrolysable inorganic monomer precursors are hydrolyzed separately from one another, followed by partial condensation of the resulting different inorganic monomers, and then mixing the resulting liquid compositions prior to carrying out step (2); wherein the amount of water used in step (2), in combination with the amount of water used in the hydrolysis of step (1) and any water liberated by condensation in step (1), is at least two times the stoichiometric amount of water required for complete hydrolysis of all the hydrolysable monomer precursors present; and wherein in step (2) of the process, further condensation is allowed to proceed, and the final product is essentially completely condensed.