Method for forming insulating coating material for electronic circuit board

A method for forming an insulating coating layer for an electronic circuit board, which method comprises:

• applying a solution consisting essentially of a perfluoroalkylacryl copolymer resin, a fluorinated solvent and a m-xylene hexafluoride solvent by spraying said solution onto the surface of an electronic circuit board with electronic elements mounted thereon,
• said fluorinated solvent being capable of dissolving said perfluoroalkylacryl compolymer resin and having a boiling point not higher than 100.degree. C. at 760 mmHg and said m-xylene hexafluoride solvent being compatible with said fluorinated solvent and having a boiling point higher than that of said fluorinated solvent,
• a mixing rate of said m-xylene hexafluoride solvent to said fluorinated solvent falling in an range of 0.1 to 20 parts by weight with respect to 100 parts by weight of said fluorinated solvent, and then
• drying said solution to form an insulating coating layer in which the thickness at edge portions having electroconductivity on the circuit board and the thickness at the other portion than the edge portions are almost equal to each other.

A method for forming an insulating coating layer for an electronic circuit board, which method comprises:

• dipping an electronic circuit board with electronic elements mounted thereon int a solution consisting essentially of a perfluoroalkylacryl copolymer resin, a fluorinated solvent and a m-xylene hexafluoride solvent,
• said fluorinated solvent being capable of dissolving said perfluoroalkylacryl copolymer resin and having a boiling point not higher than 100.degree. C. at 760 mmHg and said m-xylene hexafluoride solvent being compatible with said fluorinated solvent and having a boiling point higher than that of said fluorinated solvent,
• a mixing rate of said m-xylene hexafluoride solvent to said fluorinated solvent falling in a range of 0.1 to 20 parts by weight with respect to 100 parts by weight of said fluorinated solvent,
• pulling up the electronic circuit board from the solution to apply the solution onto the surface of said circuit board, and
• drying the solution to form an insulating coating layer in which the thickness at edge portions having electroconductivity on the circuit board and the thickness at the other portion than the edge portions are almost equal to each other.