| 摘要 |
A porous, electrical insulating adhesive substrate is made by (A) electrostatically coating a flexible sheet material with heat reactive adhesive resin particles, having an average particle size of between about 1 micron to 2,000 microns, the adhesive particles are applied in a predetermined pattern on the sheet covering from about 10 percent to 90 percent of the sheet material area, the area between the resin pattern not being coated; and then (B) heating the patterned coated sheet material between about 65.degree.C to 250.degree.C, forming a discontinuous 0.25 mil to 25 mil (0.006 mm to 0.635 mm) thick dry coating pattern of heat reactive adhesive particles bonded to the sheet material, said heat reactive adhesive coating covering from about 10 percent to 90 percent of the sheet material area; the patterned coated sheet may then be inserted as an oil permeable layer insulation between high voltage windings and low voltage windings and between layers of high and low voltage windings in a wound coil assembly, after which the assembly can be heated at a temperature and for a time effective to securely bond the winding layers together, and thus provide a porous, oil permeable, bonded transformer coil assembly. |
