Abstract: A continuous process of forming a sheet of thermoplastic material by sequentially pressing against one face of the hot sheet of material the cold tips of projections set in and extending normally from a first series of separately moveable combs and sequentially pressing against the second face of the material the cold tips of projections set in and extending normally from a second series of separately moveable combs so that the projections of the first series of combs interpenetrate with the projections of the second series of combs in such a manner that the projections of the first series are spaced from the projections of the second series by a distance greater than the thickness of the sheet; and the interpenetrated projections are substantially parallel during the act of interpenetration; and wherein the interpenetrated combs are moved along at the speed of the sheet until the sheet is set and the combs are then removed and recycled.

Abstract: A process of cold drawing a shaped plastic sheet wherein said sheet has an array of substantially parallel rows of hollow pointed projections on one or both faces; said projections having at least a portion of the distal portion of the sides at an angle of over 60.degree. to the median plane of the sheet which process comprises cold drawing the shaped plastic sheet along an axis in the plane of the sheet normal to the rows of hollow projections.

Abstract: Apparatus for deforming a sheet of thermoplastic material by sequentially pressing against one face of the hot sheet of material the cold tips of projections set in and extending normally from a first series of separately moveable combs and sequentially pressing against the second face of the material the cold tips of projections set in and extending normally from a second series of separately moveable combs so that the projections in the first series of combs interpenetrate with the projections on the second series of combs in such a manner that the projections of the first series are spaced from the projections of the second series by a distance greater than the thickness of the sheet; the interpenetrated projections are substantially parallel during the act of interpenetration; and the combs of any one series form a block pressing against the sheet of thermoplastic material, wherein the block so formed by the combs of any one series has two straight parallel sides, parallel with the sides of the thermoplas

Abstract: A process of manufacturing a cuspated sheet comprising deforming a sheet of hermoplastic material by pressing against one face of a molten sheet of the material the cold outer tips of a first array of pointed pins set in a first block and simultaneously pressing against the second face of the material the cold outer tips of a second array of projections set in a second block so that the arrays interpenetrate in such a manner that the projections on the second block are spaced from the projections of the first block by a distance greater than the thickness of the sheet and wherein the temperature of the cold outer tips of the arrays is less than the melting point of the thermoplastic material.

Abstract: A laminate comprising a core consisting of a cuspated sheet consisting of a series of hollow projections projecting upwardly and downwardly from the median plane of said sheet and wherein the outer tips of the projections on the ends furthest from the median plane are closed and the ends of the projections in the median plane are open and wherein the projections form a series of pointed cusps said core laminated to a porous sheet wherein the points of the cusps on at least one face have been melted and at least partially allowed to impregnate the porous sheet.