Patent GB-982950-A (GB)
Title: Seam structure for fourdrinier type screen fabric and method of making same
IPC: D03D1/00
Filed: 1962-06-08
Abstract: 982,950. Seaming non-metallic sheet material. CHENEY BIGELOW WIRE WORKS Inc. June 8, 1962 [June 21, 1961], No. 22228/62. Heading B5K. A Foudrinier screen fabric 1 having a non- metallic warp 2 containing synthetic organic material includes a seam having lapped end portions 6, 7 of the warp 2 embedded in a body 12 of synthetic organic material extending transversely of the fabric between and parallel to the adjacent weft elements 3 of the fabric 1 and bonding the embedded warp ends 6, 7 to each other and to the body 12. Before seaming the end portions of the fabric 1 are annealed or heat treated to remove internal strains from and to stabilize the warp 2. The fabric ends are trimmed along the terminal weft wires 3, as shown at 4 and 5, Fig. 2. The terminal wires 3 are then removed leaving the ends 6, 7 which are then flattened, as shown at 8, by swaging or pressure, under heat if desirable, and cleaned to remove any foreign matter. The ends 6, 7 are overlapped to an extent not exceeding the width of a weft wire 3 and so that the opposed warp ends interdigitate, Fig. 4. Bars 9, 10, Fig. 5, clamp the ends 6, 7 against a support, not shown. A solvent or plastic solution is applied to the ends 6, 7. The solute embedding material is either an adhesive for the warp material or is miscible therewith. For a fabric having a nylon warp 2, a solution of nylon in phenol is applied in a single or successive coats to the lapped ends 6, 7 by a dip pen. The solution is heated to 350 F. before application and after each application the temperature of the seam area is raised, preferably to a temperature between 350 and 375 F., to drive off the solvent. After each of the first two applications pressure may be applied over the seam area to hold the ends 6, 7 in position. The ends 6, 7 become integrally bonded together into a body 12. After the last coating, without drying this coating, lengths of nylon ribbon 13, 14 softened with hot phenol at 350 F. are placed longitudinally over the body 12 and the temperature of the seam area is again raised to between 350 F. and 375 F. If desired, pressure may be employed during the integration of the ribbons. In a modification, the warp 2 is nylon and the embedding material comprises a cyanoacrylate monomer which may be applied in successive coats and polymerizing, preferably at room temperature, with approximately 10% plasticizer, thickening agent and stabilizer. The monomer may contain up to 10% by weight of aluminium powder. A phenol butyral adhesive may be used. In a further modification, the warp 2 is formed of polyethylene terephthalate and the body 12 comprises one or more coatings of a solvent such as m-chloro-aniline or phenol, preferably containing about 5% polyethylene terephthalate applied at a temperature of 350- 420 F. to opposite sides of the lapped ends 6, 7. Ribbons 13, 14 of polyethylene terephthalate film coated with a polyester adhesive are applied to the body 12. In another modification, Fig. 9, for seaming a heavier fabric, the fabric ends are filled with a solid barrier material 16 which is soluble, in water for example, but insoluble in the solvents used for bonding. During the seaming, the space between the barriers 16 may be bridged with mould plates filled with the bonding composition by injection. After seaming, the barriers 16 are removed by a solvent, manually or by air blasting.