Patent GB-902812-A (GB)
Title: Film faced boards of mineral fibres and method of making same
IPC: B29C63/00
Filed: 1960-12-21
Abstract: 902,812. Laminates and laminating. OWENSCORNING FIBERGLAS CORPORATION. Dec. 21, 1960 [Dec. 24, 1959], No. 43938/60. Class 140. [Also in Groups X and XXX] Boards or panels of bonded glass or other mineral fibres are covered with a film layer by coating their edges with porous adhesive, covering an assembly of the boards, arranged in spaced relation on a flat surface, with a single film, preferably heat-softened and applying suction beneath the assembly to draw the film against the coated edges while leaving it unsecured to the faces of the boards. The film is subsequently cut between the boards. The film used is preferably unplasticized polyvinyl chloride but may be such material plasticized, polyvinylidene chloride, a polycarbonate, a fluorovinyl polymer or nylon; it may be wholly heat-softened, in which case it shows the irregular pattern of the board surfaces, or may be protected from softening over those surfaces, then having a surface which is plain or retains a pattern of previous embossing. The finished board or tile, Fig. 1A, of which the film covering is unsecured on its face 21 and is adhesively secured at its edges 24, is cut or ground away on its underside and has an undercut groove 25 for assembly on a slatted framework. Apparatus, Fig. 2, operated by electric timeswitches for carrying out the invention automatically comprises a hopper 35 containing, as shown, four piles 50 of small square tile bases, but having a wall 36 movable laterally by intergeared screw shafts 37, 38 to accommodate larger sizes. The piles 50 are supported on fingers which are withdrawn to release the four lowest units simultaneously on to a chain conveyer 33, the piles being meanwhile held between the wall 36 and a plate 52 pressed against them by the linkwork shown, and being released to fall on the fingers on their return. The released units are transferred to and spaced by a second conveyer 77 of slightly higher speed, and during travel are sprayed on their edges by nozzles 79, 80 with adhesive which is dried by radiant heaters 100, 101; they are then further spaced on a conveyer 110, and fall upon a conveyer 115 arranged at right-angles and at a lower level and having a transfer roller 114 and a guiding arm 116. A slower conveyer 119 closes the units together again and has nozzles 121, 122, and radiant heaters 127, 128 for adhesive coating, and drying, of their uncoated edges ; a conveyer 130 then assembles them for transfer to the laminating table A. The transfer apparatus comprises rods 149 carrying terminal suction cups and operated by rack and pinion mechanism to be moved axially in roller guides along slightly diverging paths; screw and other mechanism raises the tile units to contact the cups, applies suction and, on forward movement of the rods, conveys the units to, and releases them in, slightly spaced positions on the table A. The laminating table A comprises a perforated, intermittently moving conveyer belt 174 on which the units are assembled by the transfer rods 149 in equi-spaced array. A web 176 of thermoplastic film, wider than the array, is drawn from a reel 177 and pressed by a roller over the whole assembly. A chamber 183 contains radiant heaters immediately over the assembly and is connectible beneath the belt 174, to a suction chamber 188 and then to a pressure chamber 194, firstly to draw the heated and softened film 176 between the units where it adheres to their coated edges, and then to detach the film from the surface of the units. The laminated units then pass to circular blades 217 and to lateral blades, not shown, which slit the cover film between the units. The radiant heaters in the chamber 183, particularly when a pre-embossed film is used, may be screened to allow heat to reach only those parts of the film 176 to be applied to the edges of the units or may be disposed over those parts only. The laminated tiles may be finished as in Fig. 1A. If a stippled surface corresponding to that of the base is desired the tiles may be heated and then cooled to cause the film to shrink on to the surface.