Patent GB-1491228-A (GB)
Title: Production of corrugated paperboard
IPC: B31F1/36
Filed: 1974-12-10
Abstract: 1491228 Corrugated paperboard laminates KOPPERS CO Inc 10 Dec 1974 [4 Nov 1974] 53475/74 Heading B5N The quantity of blanks cut from a doubleface corrugated paperboard web made in a corrugator machine from a single-face web and a double-face liner is improved by automatically maintaining substantially constant during operation of the machine the heating time of the double-face web advancing through the machine, the amount of heat applied to the singleface web and double face liner prior to formation of the double face web and the amount of moisture applied to the single-face web and double-face liner prior to formation of the double-face web. Warp in the blanks, which may be cross-machine direction warp, machinedirection warp, S-warp or twist warp, may be observed and reduced by selectively changing at least one of the heating times of the double-face web, the relative amounts of heat applied to the single-face web and double-face liner and the relative amounts of moisture applied to the single face web and double face liner, and following the selective changing automatically maintaining substantially constant the heating time of the double-face web and the relative amounts of heat and moisture applied to the single-face web and double-face liner at selected running speeds of the machine. The bonding pressure applied to the web in the heating section, the adhesives applied to the flutes of the corrugated medium, the tension in the single face web or double-face liner and the location of the portions of the web to which moisture is applied may also be adjusted automatically. In Fig. 1 paper 13 from roll 108 is passed over a steam shower and then between corrugating rolls 104 and 106, the tips of the corrugations being coated with starch adhesive. Single-face liner 11 fed from roll 107 is passed around drum 114 in pre-heater 112 and bonded to the corrugated medium by means of heated pressure roll 105. Single-face web 12 is then passed over bridge 14 where it may be stored in folds if single facer 100 runs faster than double facer 200. A single-face web vacuum brake 150 may be supported at the downstream end of bridge 14 to produce tension which may be varied, in the single-face web between brake 150 and double-facer 200. The single-face web and double-face liner 16 fed from roll 172 are heated by passage round drums 170 and 174 respectively in pre-heater 164, sprayed with moisture by spray assemblies 166 and 168 respectively, heated by passage over rolls 180 and after the application of glue to the tips of the corrugations by roll 176 are pressed together in doublefacer 200. In the heating section 202 the doubleface web 18 is passed over a plurality of serially aligned steam-heated hot plates and pressed and advanced by ballast belt 206 provided with ballast rollers 208. It is then cooled in section 204 by passage over unheated rolls, slit into webs 20 and 22 by slitter-scorer 300 and cut into blanks by rotary knife 500. The heat applied to the single-face liner, single-face web and doubleface liner may be adjusted by varying their wrap about the drums in preheaters 112 and 164. The water spray assemblies 166 and 168 are arranged so that the amount of moisture applied across the widths of the webs may be varied. The amount of heat applied and the heating time in the double-facer 200 may be varied by adjusting the number of ballast rollers 208 in contents with belt 206 and the number of hot plates over which the double-face web is passed. Belt lifters and air pressure may be used in double-facer 200 to prevent damage to the web.