A method preparing organically reinforced electroinsulating materials

摘要

In the production of electrically insulating material based on thermosetting synthetic binder resin and wood flour, the wood flour is pre-impregnated with an aqueous or aqueous alcoholic solution of a phenol resol which has a molecular ratio of phenol to formaldehyde of 1 to 0.5-3 and has been prepared in the presence of calcium oxide, the calcium oxide having been precipitated by carbon dioxide after the preparation. The resol may be admixed with 5-20% of 30% formalin and 1-10% of 25% ammonia based on the wood flour. The impregnated wood flour may be dried at 100-160 DEG C. The impregnated wood flour may be mixed with phenol novolac, hexamethylenetetramine, stearin, fluorite, and lac black, calendered at 100-120 DEG C., cooled, crushed, and pressed.ALSO:In the production of electrically insulating material based on thermosetting synthetic binder resin and a cellulose filler, for example in the form of wood flour, paper or textile material, the cellulose filler is pre-impregnated with an aqueous or aqueous alcoholic solution of a phenol resol which has a molecular ratio of phenol to formaldehyde of 1 to 0.5-3 and has been prepared in the presence of calcium oxide, the calcium oxide having been precipitated by carbon dioxide after the preparation. When the filler is in the form of wood flour, the resol may be admixed with 5-20% of 30% formalin and 1-10% of 25% ammonia based on the wood flour. The impregnated wood flour may be dried at 100-160 DEG C. When the filler is in the form of paper or textile, material, the resol may be admixed with a phenol novolac in the ratio of 1 to 0.5-3. The impregnated paper or textile material may be dried at 120 - 180 DEG C.