Patent GB-891715-A (GB)
Title: Improvements relating to the manufacture of sheet-like mats
Inventor: JR ROBERT LEE JACKSON
IPC: D04H3/07
Filed: 1958-02-17
Abstract: 891,715. Forming fibrous mats. AMERICAN AIR FILTER CO. Inc. Feb. 17, 1958, No. 5116/58. Classes 120(1) and 120(3) [Also in Group VIII] A sheet-like filamentous mat comprises a plurality of overlying layers of filamentous material in which at least one layer includes a succession of transversely spaced, substantially straight non- crossing multi-filament collected cords and also includes other multi-filament collected cords which are generally undulated or curled in the plane of the mat. The said layer may also include a succession of substantially straight non-crossing monofilaments and also monofilaments which are generally undulated or curled. The multifilament collected cords or monofilaments of one layer may lie generally in crossed relationship to the multi-filament collected cords or monofilaments of an adjacent layer. The mat may include a binder of the filamentous material. The filaments may be of glass. One face of the mat may be provided with a backing ply composed entirely of monofilaments. As shown in Fig. 1, the mat comprises a group of spaced multi-filament collected cords 2 extending generally straight in one direction, another group of similar cords extending generally straight in another direction and crossing the first group, a third group of cords 4 which are curled or undulated in the plane of the mat, and a plurality of separated individual monofilaments 5. As shown (Figs. 4 and 5) apparatus for making the mat according to the invention comprises a drum 10, journalled for rotation, and driven by belt 12; a glass furnace 13 supported for reciprocation along rails 15; a group of spinnerets (not shown) on the bottom of furnace 13 for feeding individual glass filaments 16 to the drum; filament collector wheel 18 supported by bracket 17; and horizontal discharge pulley 20. The apparatus comprises two additional glass furnaces 23, 23<SP>1</SP>, stationarily mounted beyond one end of drum 10 and co-operating with collector wheels 18<SP>1</SP> and 18<SP>11</SP> and discharge pulleys 20<SP>1</SP> and 20<SP>11</SP>. In operation the furnace 13 is reciprocated while drum 10 is rotated a multiplicity of times during each traverse of the furnace; the filaments 16 from the furnaces are fed to the respective collector wheels which form them into cords 19 which are fed to the respective discharge pulleys and thence delivered to the rotating drum. There is thereby built up on the drum, during successive traverses of the furnace, a cylindrical condensed mat 21 having a succession of layers each containing a plurality of helical turns of collected filament cords. The mat is thereafter slit axially and removed from the drum. The traversing speed of the furnace is varied in a cyclically repetitive pattern between maximum and minimum values one or more times during each traverse. In order to form a mat having layers containing both collected filament cords and individual separated filaments, the winding may be carried out as shown in Fig. 6, wherein a portion of the filaments, 16<SP>1</SP>, from furnace 13 are fed directly to the periphery of the drum 10. After removal from the drum, the mat may be stretched axially, (Fig. 9) to form an elongate expanded thickness web 29 which is conveyed by conveyer 30 through a bath of binder liquid 32 wherein it is compressed by roller 33 and then passes over suction device 35 and through heater 37 and is wound on roll 38. The configuration of the cords in the finished mat is determined by the helix deposition angle. Upon stretching the mat, the cords disposed at greater helix angles form the substantially straight cords and the cords of lesser helix angle form the undulated cords.