Patent GB-1325017-A (GB)
Title: Process and appa'atus for making ribbed synthetic resin boards
IPC: B29C48/08
Filed: 1970-10-12
Abstract: 1325017 Laminates; ribbed structures SEISAN NIPPONSHA KK 12 Oct 1970 [22 Oct 1969] 48394/70 Headings B5A B5B and B5N A process for the production of a composite structure comprising a ribbed structure c having an integral film 6 bonded to at least one surface thereof, comprises extruding a ribbed structure of a synthetic resin from a fluted roller through a slot, and extruding a film of a synthetic resin from an orifice on to one surface of the ribbed structure at the speed at which the ribbed structure is extruded. In a preferred embodiment, a sandwich structure is produced by extruding a second film 6<SP>1</SP> of a synthetic resin from a second orifice on to the other surface of the ribbed structure at the speed at which the ribbed structure is extruded. The ribbed structure may be stretched in a direction perpendicular to the direction of advance thereof prior to or after extrusion of the first film. The second film may be extruded simultaneously with or after the extrusion of the first film and before or after stretching the composite of the ribbed structure and the first film. An apparatus for effecting the process of the invention comprises a fluted roller 2 for forming the ribbed structure, means for extruding said ribbed structure from the fluted roller through a slot 3, an orifice 30 for extruding a film on to one surface of the ribbed structure at a speed at which the ribbed structure is extruded, means for supplying a synthetic resin to the fluted roller and to the orifice and stretching means for stretching the ribbed structure in a direction perpendicular to its direction of advance comprising a pair of spaced rollers 5a, 5b, a doctor blade 15a, 15b disposed above each roller and means for adjusting the spacing between the rollers and the blades. With reference to Fig. 5, the ribbed structure formed at the fluted roller 2 is combined at slot 3 with a film emerging from orifice 30 and the resultant composite stretched in the nip between rollers 5a and 5b, the thickness of the ribs of the composite emerging from the nip being dependent on the spacing of the rollers 5a and 5b and of the individually adjustable doctor blades 15a and 15b. In the embodiment described, a second film is extruded through orifice 38 on to the exposed surface of the ribbed structure after stretching of the composite of the first film and the ribbed structure. The resin is forced through inlet 21 into first manifold 22 and then uniformly into second manifolds 25 and 26 via passages 23 and 24 provided in rows and part thereof introduced into chamber 25<SP>1</SP> containing the fluted roller, other portions of the resin being fed from manifolds 25 and 26 through passages 27 and 28<SP>1</SP> to nozzles 28 and 35 and then to orifices 30 and 38, the flow of resin through a choke 37 being provided to regulate the resin flow. In the embodiment of Figs. 6 and 7, a spacer 40 is provided between the second nozzle 35 and the intermediate member 33, the nozzle being slidably mounted on the spacer and a variable manifold 42 to enable adjustment of the lip position of the orifice 38 to be effected. The ribbed structure may be in the form of a honeycomb of intersecting ribs; alternatively the ribs may be separated from one another.