a web of thermoplastic material and a method and apparatus for manufacture of the web are disclosed with the web having a repeating pattern of alternately thick and thin portions . a molten thermoplastic material is extruded through a duct between a first rotatable driven roll and a circular - cylindrical seat . the first driven roll includes a surface having a pattern of recessed portions . the web is transferred from the first driven roll to a second driven roll having a smooth surface . the temperatures of the first and second rolls may be selectively maintained . the thermoplastic material may be extruded through a plurality of ducts leading to the surface of the first driven roll . transfer of the web from the first roll to the second may be encouraged by means of a vacuum . furthermore , complete filling of the recesses of the first driven roll by the thermoplastic material may be encouraged by the use of a vacuum .