Inorganic polysilazane resin

Abstract

An inorganic polysilazane resin of the present invention has a Si/N ratio (i.e. a ratio of contained silicon atoms to contained nitrogen atoms) of 1.30 or more. The inorganic polysilazane resin having such a high Si content can be produced by, for example, a method in which an inorganic polysilazane compound containing both Si—NH and Si—Cl is heated to react NH with Cl, a method in which a silazane oligomer (polymer) that leaves no Si—Cl bond is synthesized and a dihalosilane is added to the synthesized silazane oligomer (polymer) to perform a thermal reaction, and the like. A siliceous film can be formed by, for example, applying a coating composition containing the inorganic polysilazane resin onto a base plate and then dried and the dried product is then oxidized by bringing the dried product into contact with water vapor or hydrogen peroxide vapor and water vapor under heated conditions.

1 . An inorganic polysilazane resin, wherein a ratio of containing silicon atoms to containing nitrogen atoms, Si/N is 1.30 or more. 
     
     
         2 . The inorganic polysilazane resin according to  claim 1 , wherein a ratio of containing silicon atoms to containing nitrogen atoms, Si/N is 1.32 or more 
     
     
         3 . The inorganic polysilazane resin according to  claim 1 , which weight-average molecular weight in terms of polystyrene is 1,200 to 20,000. 
     
     
         4 . The inorganic polysilazane resin according to  claim 1 , which is produced by heating an inorganic polysilazane compound containing both Si—NH and Si—Cl to react NH with Cl. 
     
     
         5 . The inorganic polysilazane resin according to  claim 4 , wherein the heating is conducted in the presence of a catalyst. 
     
     
         6 . The inorganic polysilazane resin according to  claim 5 , wherein the catalyst is a tertiary amine. 
     
     
         7 . A inorganic polysilazane resin according to  claim 1 , which is produced by synthesizing a silazane oligomer or polymer with no Si—Cl bond and then thermally reacting the synthesized silazane oligomer or polymer with an added halosilane. 
     
     
         8 . The inorganic polysilazane resin according to  claim 7 , wherein the halosilane is a dihalosilane. 
     
     
         9 . A coating composition containing the inorganic polysilazane resin according to  claim 1 . 
     
     
         10 . A method for forming a siliceous film, wherein the coating composition containing the inorganic polysilazane resin according to  claim 9  is applied to a substrate and oxidized by contacting with a water vapor under a heated condition after drying. 
     
     
         11 . A method for forming a siliceous film, wherein the coating composition containing the inorganic polysilazane resin according to  claim 9  is applied to a substrate and oxidized by contacting with a hydrogen peroxide vapor and a water vapor under a heated condition after drying. 
     
     
         12 . A siliceous film, which is formed by the method for forming a siliceous film according to  claim 10 . 
     
     
         13 . The siliceous film according to  claim 12 , of which shrinkage is 15% or less.