| 摘要 |
756,303. Filters. FRAM CORPORATION. Nov. 12, 1954 [Dec. 8, 1953], No. 32860/54. Class 46. [Also in Group XXVIII] A method of securing metal closure discs 15 to the ends of a filter element 10 comprising an annulus of porous fibrous filter material, such as resin-impregnated paper, having pleats extending lengthwise comprises applying a film of lacquer 20 and then a layer of paste 21 formed of a vinyl resin powder and a plasticizer to one face of each of the discs 15, forcing the thus-coated discs against the ends of the annulus and heating the discs, while they are so held, to the softening point of the resin to transform it to a continuous phase that firmly bonds the discs to the annulus. The lacquer 20 (preferably formed of vinyl resin), is allowed to dry or is baked before application of the paste. To prevent any tendency for the paste to drip or run down the pleats a gelling agent may be added to it or it may be heated to a temperature below the softening point of the resin to cause gelling before the discs are applied to the ends of the annulus.
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