Modified polysilazane film and method for producing gas barrier film

A method for producing a gas barrier film using a modified polysilazane film comprising a substrate and a modified polysilazane layer formed thereon, comprising the following steps (1) to (3):

• (1) a polysilazane layer forming step, comprising forming a polysilazane layer on the substrate, wherein a composition used for forming the polysilazane layer comprises a polysilazane compound having a repeating unit represented by the following general formula (1):
• wherein in the general formula (1), Rx, Ry and Rz each independently represents a hydrogen atom, or a non-hydrolysable group selected from the group consisting of an alkyl group being unsubstituted or having at least one substituent, a cycloalkyl group being unsubstituted or having at least one substituent, an alkenyl group being unsubstituted or having at least one substituent, an aryl group being unsubstituted or having at least one substituent, and an alkylsilyl group, and the subscript n represents an arbitrary natural number;
• (2) an intermediate treatment step, comprising heat-treating the polysilazane layer obtained in step (1) and then air-conditioning-treating the polysilazane layer at a temperature below that of the heat-treating to form the modified polysilazane layer having a thickness of a value in the range of 10 to 500 nm, a refractive index of a value in the range of 1.50 to 1.58, and an oxygen amount measured by X-ray Photoelectron Spectroscopy of a value in the range of 30 to 58 mol % with respect to the overall amount, taken as 100 mol %, wherein the overall amount is the total amount of the silicon amount, oxygen amount and nitrogen amount, to thereby give the modified polysilazane film as an intermediate material, wherein conditions for the heat treatment of the polysilazane layer include a heating temperature of 60 to 140° C. and a heat treatment time of a value in the range of 30 seconds to 60 minutes, and conditions for the air-conditioning treatment include leaving the polysilazane layer on the substrate under atmospheric conditions at a temperature of 15 to 35° C. under a relative humidity of 40 to 60% for 24 hours to 10 days;
• and
• (3) a plasma ion implantation step, comprising conducting a plasma ion implantation process into the modified polysilazane layer of the modified polysilazane film obtained in step (2) to form the modified polysilazane layer into a gas barrier layer to thereby give the gas barrier film comprising the substrate and the gas barrier layer formed thereon, wherein the plasma ion implantation process comprises generating plasma in an atmosphere containing a plasma generating gas, and applying a plasma ion implantation pressure adjusted to a value within the range of 0.01 Pa to 1 Pa and a negative high voltage pulse with an applied voltage adjusted to a value within the range of −1 kV to −50 kV.