GB2131742A

GB2131742A - Corrugating apparatus

Info

Publication number: GB2131742A
Application number: GB08333158A
Authority: GB
Inventors: Webster C Roberts
Original assignee: Molins Machine Co Inc
Current assignee: Molins Machine Co Inc
Priority date: 1982-12-13
Filing date: 1983-12-13
Publication date: 1984-06-27
Also published as: JPS59155031A; DE3344941C2; FR2537501A1; DE3344941A1; JPH0364299B2; GB8333158D0; GB2131742B; FR2537501B1

Abstract

An apparatus for making a web of corrugated paperboard 42 or 73 includes first and second corrugating rolls 20, 22 for corrugating a medium 14 passing therebetween, a means 24 for applying electron beam curable adhesive 30 to the crest of flutes while the corrugating medium is on the second corrugating roll and an electron beam generator means 36 for causing the adhesive to cure and bond the flute crest on one side of the medium to a liner. A second liner may be bonded to the other side of the medium, and the adhesive used for that purpose may be cured by the same electron beam generator means (Figure 3). <IMAGE>

Description

SPECIFICATION Corrugating apparatus A conventional paperboard corrugator is a plurality of separate machines arranged in a particular sequence and having a total length of about 100 metres. A corrugator includes a single facer machine, a bridge, and a double facer machine arranged in that sequence. The single facer machine, bridge, and double facer machine occupy about 40 to 50 percent of the length of the corrugator and require the greatest energy input.

Present energy input involves the use of steam heated rollers and steam heated chests which must meet boiler code specifications and require substantial time before they reach their operating temperature of about 3000F.

The present invention is directed to a solution of the problem of reducing the length of the corrugaton As will be made clear hereinafter, the problem has been solved by radically changing the "wet end" of the corrugator which includes the single facer machine and the double facer machine as well as the form of energy input.

This invention is concerned with using an electron beam curable adhesive (in place of the conventional starch adhesive) for bonding a corrugated medium to at least one liner to form corrugated paperboard. In particuiar this invention revolves around an appreciation that electron beam curable adhesive enables a single facer machine and a double facer machine to be combined without the conventional bridge.

The corrugated medium is preferably (as is common) corrugated in that it has transverse flutes, but the flutes could in principle be longitudinal.

The adhesive is preferably (as is common) applied to the crests of the flutes of the medium, but could in principle be applied to the liner in the form of spaced stripes to coincide with the crests of the flutes when the medium and liner are brought together.

Examples of apparatus according to this invention are shown in the accompanying drawings. In these drawings: Figure 1 is a vertical sectional view of apparatus in accordance with the present invention; Figure 2 is a view similar to Figure 1 but illustrating a second embodiment of the present invention; and Figure 3 is a view similar to Figure 1 but illustrating a third embodiment of the present invention.

Referring to the drawings in detail, wherein like numerals indicate like elements, there is shown in Figure 1 apparatus in accordance with the first embodiment of the present invention wherein a frame 11 supports a single facer machine 10 and a double facer machine 12, one above the other.

The frame 11 is illustrated diagramatically and may assume a wide variety of configurations. If desired, separate frames may be provided for each of the machines 10 and 12.

At the single facer machine 10, a web 14 (the "medium") passes over a steamer 16, around idler roller 18, and into the nip between corrugating rolls 20 and 22. The rolls 20 and 22 have longitudinally extending corrugations meshed with one another. The corrugating roll 22 preferably is of the vacuum type so as to eliminate the need for fingers. A wide variety of vacuum corrugating rolls are known to those skilled in the art. Vacuum is utilized to hold the corrugations in contact with approximately 1800 of the peripheral surface of roll 22. Alternatively, the corrugations may be formed by above-atmospheric pressure supplied to an external chamber extending partly around the roll 22.

A vessel containing adhesive 30 is supported by the frame 11 below the elevation of the corrugating rolls 20, 22. Adhesive 30 is applied to the crests of flutes of the medium 14 while the latter is held onto the outer periphery of roll 22 by an applicator roll 24. A doctor roll 26 having a doctor blade 28 is provided in association with the roll 24. The bonding agent 30 is not of the conventional starch type but rather is preferably 100% solids (free of solvents and water) and in the form of a monomer.

A liner 32 may be fed from the right, or from the left as shown in dotted lines in Figure 1, and around an idler roller 34. Liner 32 is fed into contact with the crests of the flutes of the medium 14 and is held in such contact by idler rollers 40 and 41. Rollers 40,41 are mounted within the housing 38. Within or adjacent housing 38 there is provided an electron beam generator means 36.

The interior of housing 38 is preferably filled with an inert gas such as nitrogen at a pressure of about 1 inch (25 mm) water gauge. The inert gas is continuously fed into housing 38 via conduit 39 to replace gas that escapes. Depending on the web speed, gas is introduced at a rate of .5 to 1.5 M3 per hour per cm of web width.

As presumably understood, the curing, drying and hardening effect is based on a free radical chain reaction. Energized electrons from the beam break the chemical bonds in the adhesive to form free radicals. The free radicals combine with other radicals and create in milliseconds a higher density polymeric network or chain of monomers, resulting in a cured adhesive. At the proper energy level and exposure period (hereinafter "dose") the adhesive is perfectly dry and there is an absence of the typical odor of the acrylate combinations of epoxies, urethanes, and polyesters.

The impact speed of low energy electrons, with the help of clouds of secondary electrons, leads to instant drying without creating excessive heat. In curing of adhesive with a typical dose of 1 to 4 Mrads, the temperature rise is not more than 5 to 1 00C. Very often no temperature rise of the web can be detected. The energy to cure adhesive is generally not more than 4 kcal per kg of adhesive. Thus, the energy to cure adhesive is only 1% or 2% of the energy needed to dry and cure a solvent. The enert gas in housing 38 prevents the free radicals from combining with oxygen.

Web 42 thus formed by the joining of liner 32 to corrugated medium 14 moves upwardly from the single facer machine 10 and around an idler roller 44 and then below idler roller 46. As a result, the crests of the flutes on the other side of the medium 14 are now in a position for contact with applicator roll 48. Roll 48 is provided with a doctor roll 50 in the same manner as described above. The adhesive 52 is applied to the exposed crests of the flutes.

The single-faced web 42 then passes around idler rolls 54, 56 and enters housing 58 of the double facer machine 12 by way of inlet opening 62. Housing 58 is provided with an outlet opening 64. Between said openings, there is provided a support plate 60 within housing 58.

An endless belt 66 is trained around a plurality of idler rolls 68 at an elevation immediately above the support plate 60. A tension roll 69 contacts the outer peripheral surface of the belt 66. Roll 69 is adjustable in a conventional manner. An electron beam generator means 70 is disposed within housing 58 and within the loop of belt 66.

The interior of housing 58 preferably has an inert gas as described above. A liner 72 enters the housing 58 through the inlet opening 62 and is bonded to the crests of the flutes of the web of single-faced web 42 by the electron beam generator means as described above. The resultant is a web of double-faced paperboard 73 exiting from the opening 64 of the housing 58.

By positioning the double facer machine 12 directly above the single facer machine 10, substantial floor space is saved. If desired, the double facer machine 12 may be downstream from the single facer machine 10 and at the same elevation. The combination single facer machine and double facer machine as illustrated in the drawing may reduce the length of the corrugator by up to 50 meters or by even more, the conventional bridge between the two machines being eliminated. The apparatus may be operated immediately after a preliminary warm-up time for rolls 20, 22 which are steam heated rolls.

In Figure 2 there is illustrated another embodiment of the present invention which is identical with that described above except as will be made clear hereinafter. Corresponding elements are provided with corresponding prime numerals.

As shown in Figure 2, the single facer machine 10' has a single applicator roll 24' without any doctor roll 26. A doctor blade is provided for cleaning the surface of roll 24'. In like manner, applicator roll 48' applies adhesive 52' to the crests of the flutes on the web of single-faced paperboard 42'. At the double facer machine 12', an endless belt 74 is trained around idler rolls 76.

The upper run of the belt 74 is between the support plate 60 and the web of single-faced paperboard 42'.

In Figure 3, there is illustrated another embodiment of the present invention wherein a combination single facer machine and double facer machine is designated generally as 80. A medium 86 passes into the nip between meshed corrugating rolls 82, 84. Roll 84 is preferably of the vacuum type as described above. An adhesive 88 is applied to the exposed crests of the flutes of the medium 86 by an applicator roll 90. A doctor roll 92 may be provided for cleaning the surface of roll 90.

A liner 94 is unwound from a roll and passes around idler rolls 96, 98, 100, 102 and thereafter contacts the exposed crests of the flutes of the medium 86. Electron beam generator means causes the adhesive bonding agent to bond the crests of the flutes of medium 86 to the liner 94 while such flutes are still in contact with the outer periphery of the corrugating roll 84 to thereby form a web of single faced paper board 106.

The electron beam generator means 104 is disposed adjacent to or within the housing 108.

The interior of housing 108 is filled with an inert gas as described above. The inert gas is continuously introduced into housing 108 via conduit 109. The web of single-faced paperboard 106 is trained around idler rolls 110 and 112.

While the web is supported by the roll 110, adhesive 11 4 is applied to the exposed crests of the flutes by the applicator roll 11 6. Roll 11 6 has a doctor roll 11 8.

Thereafter, the web 106 enters the housing 108 and is bonded to a liner 120 by the electron beam generator means 104. Idler rollers 1 22 are provided within the housing 108 to support the web of double-faced paperboard 124. It will be noted that the web 124 and all of its components move from left to right. Thus, medium 86 and liners 94, 120 are unwound from large rolls (not shown) to the left of the apparatus 80 in Figure 3.

The web 1 24 also is discharged to the right in Figure 3 for further processing downstream in a conventional manner. The apparatus 80 has the advantage of only requiring one electron beam generator means for curing the adhesive for forming the bond between medium 86 and liner 94 as well as the bond between web 106 and liner 120. The adhesives 88, 114 are the same as those described above. The vairous electron beam generator means disclosed herein are commercially available devices.

The space between the rolls 102 and 112 (below the roll 84) may be supplied with inert gas which may be at a pressure slightly above that in the housing 108 so as to press the single-faced web onto the liner 120; for that purpose the liner 120 may be further supported by fixed plates and/or possibly by a belt passing around the rolls 122 and below the electron beam generator means 104. Other arrangements may alternatively be provided in this embodiment and in the other embodiments for pressing the medium and liner together by air or gas pressure while the adhesive is being cured by the electron beam generator means.

Other advantages of the present invention include the elimination of the conventional pressure roll at the single facer machine. Liners 72, 72' may be preprinted liners. Because there is no degradation due to halting movement of the double faced paperboard as was the case in connection with conventional double facers, interruption due to order changes can be tolerated, thereby making possible new dry end configurations.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims

1. Apparatus for making a web of corrugated paperboard, including means for applying an adhesive for joining to a liner web the crests of flutes on one side of a corrugated medium, and electron beam generator means for causing said adhesive to cure and bond said fluted crests to the liner.

2. Apparatus in accordance with claim 1 including electron beam generator means for causing an adhesive on crests located on the other side of the medium to cure and to bond the medium to another liner and thereby form doublefaced paperboard.

3. Apparatus in accordance with claim 2 wherein a single electron beam generator means is provided for curing adhesive at each of said bonds at a location adjacent a corrugating roll.

4. Apparatus according to claim 3 in which the medium is arranged to pass around the corrugating roll initially with one liner and then to return together also with the second liner along a straight path spaced from the corrugating roll, the electron beam being directed towards the corrugating roll so as to pass twice through the medium and the first of the liners.

5. Apparatus in accordance with claim 2 wherin said electron beam generator means are discrete units, the second mentioned electron beam generator means being downstream from the first mentioned electron beam generator means.

6. Apparatus in accordance with any previous claim including means for applying the second liner at a location above the location wherein the first liner is applied to the medium.

7. Apparatus in accordance with any previous claim including first and second corrugating rolls for corrugating a medium, said adhesive applying means including a roller for applying adhesive to crests of flutes of a medium while the medium is on the outer periphery of a corrugating roll.

8. Apparatus in accordance with claim 4 including a housing through which a web of single faced paperboard and liner move, said housing including the second electron beam generator means therewithin, and at least one endless belt within said housing for moving the liner and web of single faced paperboard through the housing.

9. Apparatus according to any one of claims 1 to 8 including a housing through which the electron beam is arranged to pass to cure the adhesive, and means for purging the housing with an inert gas.

10. Apparatus comprising a combined single facer machine and double facer machine for making double-faced paperboard comprising first and second corrugating rolls for corrugating a medium, first means for applying an adhesive to the crests of flutes while the corrugated medium is on the second corrugating roll, means for feeding a liner into contact with the crests of flutes on the second corrugating roll, electron beam generator means for causing the adhesive to cure and bond said flute crests on one side of a medium to a first liner and thereby produce a web of single faced paperboard, means for applying adhesive to the crests of flutes of the web of single-faced peperboard, means for feeding a second liner into contact with the crests of flutes of the web of single faced paperboard, and electron beam generator means for curing the last mentioned adhesive and bonding the second liner to the web of single faced paperboard thereby producing a web of doubpe faced paperboard.

11. Apparatus in accordance with claim 10 wherein a single electron beam generator means is provided for curing each adhesive.

12. Apparatus in accordance with claim 11 wherein said electron beam generator means is disposed at an elevation below and adjacent to the second corrugating roll.

13. Apparatus in accordance with claim 12 including means for guiding the web of singlefaced paper board downwardly and then horizontally so that the exposed crests are on the lower surface thereof, said means for feeding the second liner being arranged to direct the second liner into contact with the crests on said lower surface at an elevation between the elevations of said corrugating roll and electron beam generator means.

14. A method of producing corrugated paperboard comprising feeding a corrugated paper web medium, feeding a liner web towards the medium, applying electron beam curable adhesive to join the liner to the corrugated medium and curing said adhesive by directing an electron beam at a predatermined region while moving the medium and liner through said region.

1 5. A method in accordance with claim 14, including purging said region with an inert gas.

16. A method in accordance with claim 14 or claim 1 5 in which the adhesive is substantially free from water or other solvent.

1 7. A method according to claim 1 5 or claim 1 6 in the medium with the first-mentioned liner is arranged to pass through the said region a second time together with a second liner and with additional adhesive to join the second liner to the medium.

1 8. A method of producing corrugated paperboard comprising: (a) providing a moving medium having transverse corrugations defined by alternating crests, (b) applying adhesive to crests of the corrugations, (c) sequentially joining first and second liners to said alternating crests on opposite sides of said medium, and (d) curing said adhesive applied to said crests by directing an electron beam thereto in the presence of an inert gas.

19. A method in accordance with claim 18 including providing a housing having an inert atmosphere, and performing at least a portion of steps (c) and (d) in said housing.

20. Apparatus for making corrugated paperboard, substantially in accordance with any one of the examples described with reference to the accompanying drawings.

21. A method of making corrugated paperboard, substantially in accordance with any one of the examples described with reference to the accompanying drawings.