EP0662045B1 - Machine and method for making a sheet of single face corrugated cardboard - Google Patents

Abstract

PCT No. PCT/FR94/00896 Sec. 371 Date May 15, 1995 Sec. 102(e) Date May 15, 1995 PCT Filed Jul. 18, 1994 PCT Pub. No. WO95/03166 PCT Pub. Date Feb. 2, 1995A machine for manufacturing a sheet of corrugated board by gluing a fluted sheet of board onto a liner sheet of board includes: a fluted cylinder, a central fluted cylinder equipped with an assembly for applying the fluted sheet against its periphery, a smooth cylinder for bringing the liner sheet into contact with the crests of the flutes of the fluted sheet, and a motorized smooth heating cylinder situated downstream of a path of the corrugated board and entirely at distance from the first three cylinders; an assembly for controlling and adjusting the rotational speed of the motorized smooth heating cylinder; and an assembly for adjusting and maintaining during operation the pressure of the liner sheet on the flutes of the fluted sheet over a line of contact below 3 kg/cm. The fourth cylinder presses the fluted sheet onto the central fluted cylinder over an circular arc corresponding to a subtended angle between an order of 30 DEG and an order of 80 DEG . The fourth cylinder contacts with the back of the liner sheet over an circular arc corresponding to a subtended angle between an order of 90 DEG and an order of 200 DEG .

Description

The present invention relates to manufacturing corrugated cardboard and more particularly a cardboard sheet making machine single-sided corrugated by gluing a sheet fluted cardboard on a flat sheet of cardboard so-called cover sheet, of the type comprising three substantially tangent heating cylinders two to two, of parallel axes, namely a first grooved cylinder, sheet pre-forming fluted, a second cylinder, fluted, central, associated with means for applying the sheet grooved against its periphery, and a third cylinder, smooth, supplying the flat sheet in contact with the grooves of the grooved sheet, at the periphery of the second cylinder, as well as means for gluing splines before contact between fluted sheet and cover sheet.

It also relates to a method of manufacture of single-sided corrugated cardboard sheets using in particular a machine of the above type.

It finds a particularly important, although not exclusive, application in the field of manufacturing single-sided sheet at high speed, with cardboard obtained from recycled paper with a low grammage (less than about 150 g / m ² ). .

We already know machines of the above type defined.

There is thus shown in Figure 1 a machine 1 of the prior art in a chain of manufacture 2 of single-sided corrugated cardboard.

The chain includes supply means 3 and 4 respectively in flat sheet, of cover, and in flat sheet intended to form the sheet grooved.

These supply means include, so known in itself, from the reels 5 which allow good control of the progress and braking necessary for the production of cardboard.

They also include a preheater 6, for the cover sheet, generally consisting a steam heated steel cylinder small rollers called "bar feeders" which are used to vary the paper / roll contact surface, and a preconditioner 7 for the fluted sheet, which in turn, and in addition, a ramp humidification of the leaf which promotes formation of grooves.

The chain 2 also includes means evacuation 8 of the single-sided cardboard obtained, constituted by a system of belts partly high of the chain.

Figure 2 shows more specifically, in view cutting, the machine 1 single face of the chain of figure 1.

It includes, on the food side corrugated sheet, a preheater cylinder additional 9 and a humidifying cylinder 10, and on the sheet feeding side cover, two rotating preheater cylinders 11.

The machine 1 also includes a first cylinder 12, grooved, upper, steel stainless. It is hollow and designed to be heated steam in a manner known per se.

Machine 1 also includes a second cylinder 13, grooved, central, stainless steel, axis parallel to that of the first cylinder substantially tangent to the latter, and for example from same diameter.

The second cylinder is for example of the type known as "Air Drive", manufactured by the French company MARTIN.

It has two bedrooms, namely a bedroom steam-heated plant and a vacuum chamber 15 connected to a vacuum device 16. The chamber includes 17 channels drilled all over the length of the cylinder and communicates with the peripheral surface fluted by holes.

Machine 1 includes a third cylinder 18 lower, smooth surface, axis parallel to first two and for example of the same diameter. This cylinder is similarly steam heated to the first two and is arranged to compress the cover sheet against the edges of grooves of the grooved sheet, in contact with the periphery of the central grooved cylinder, as we go see it.

The machine 1 also comprises means 19 for gluing the ridges of the grooves, known in themselves, comprising a laminating roller 20, a tray glue 21 and a glue roller 22.

The operating principle of the machine 1 is the next.

Two sheets or sheets of cardboard paper 23 and 24 are introduced into machine 1.

The sheet 23 is intended to form the sheet grooved.

After drying and humidification treatment in 7, 9 and 10, it goes around the first cylinder fluted heater 12, on part of its periphery.

It is then introduced between the two fluted heating cylinders 12 and 13 which rotate in reverse of each other, like two gear cylinders.

The vacuum created in the lower part of the cylinder 13 then plates the fluted sheet 23 formed against the heating cylinder on an arc of circle with an apex angle equal to around 180 °.

When passing in front of the glue roller 22, a line of glue is, moreover and as we have seen, deposited at the crest of the grooves.

The glue is for example based on starch.

The cover sheet 24 is introduced in the lower part and opposite the machine 1.

It is pre-dried at 11 and wrapped around the third cylinder 18, also called press smooth. Very high hydraulic pressure, by example of 5 kg / cm (linear pressure), ensures a successive contact at 25 (see Figure 3) between each upper edge of leaf grooves fluted 23 and the cover sheet 24 of paper smooth.

The adhesive joint is therefore obtained by the action combined with high pressure and temperature in a fraction of a second.

The training of the leaves is done by traction, the fluted sheet being driven by the meshing of the grooved cylinders 12 and 13, and the cover sheet being driven by clamping between the central cylinder 13 and the smooth cylinder 18.

Other types of single sided machines exist, such as those where the leaf fluted is pressed by air instead of being vacuumed on the central cylinder.

Their operating principle and the elements structural they implement remain however in general identical to those described above.

Although they achieve strong rates by giving a single sided paper acceptable, known machines have however always drawbacks.

In particular, to obtain a good bonding, this which is the goal if you want a box corrugated of good quality, we considered, until day it was necessary to apply both leaves on top of each other with very strong pressure, it being further understood that sufficient temperature is maintained at the time of bonding to allow gelatinization of the glue.

Unfortunately and in particular this pressure has harmful effects.

It is indeed applied to the part upper ridges of the grooves (see figure 3), which causes cardboard cuts in particular to resonant speeds, or even to high speeds.

In addition the application of the pressure cylinder 18 on the central grooved cylinder 13 discontinuously, from one groove to another, vibrations and significant noise (105 to 110 decibels at high speed) are generated.

This results in a bad corrugated cardboard quality, including resistance characteristics moisture and shattering of the cover, for example, are lessened.

The document EP-A-0 492 310 describes a machine corresponding to the preamble of claim 1, and implementing belted systems, fragile and exerting strong pressure.

The same is true of document DE-2,527,819.

Document EP-A-0 492 310 concerns before him a system for manufacturing cardboard corrugated for edge-to-edge plates, which has disadvantages including this fact.

The present invention aims to provide a carton making machine and method wavy single sided responding better than those previously known to the requirements of practice, especially in that it allows to remove practically paper cuts at speeds of resonance and / or at high speed, i.e. by example greater than 300 m / min, and in that it provides excellent bonding, which produces corrugated cardboard of improved performance and this for a low cost and easy to set up artwork.

Existing machines can also be easily adapted to take advantage of the improvement of the present invention.

To do this, the present invention starts from a an entirely new idea, including significantly reduce the pressure, or even at the totally remove, between the grooved cylinder 12 and the cylinder 18 smooth on the contact surface between the sheets, and unlike this that the prior art taught, replacing the high pressure by prolonged heating of sheets against each other.

For this purpose the present invention provides especially a sheet manufacturing machine single-sided corrugated cardboard by gluing a corrugated sheet of cardboard on a flat sheet of carton according to claim 1.

Advantageously control means and adjusting the speed of rotation of said fourth cylinder with respect to the speed of rotation of said second cylinder (or what is equivalent, to the running speed of the corrugated board) are by elsewhere planned.

• la première valeur déterminée est comprise entre de l'ordre de 30° et de l'ordre de 80° ;
• la première valeur est de l'ordre de 60° ;
• la seconde valeur déterminée est comprise entre de l'ordre de 90° et de l'ordre de 200° ;
• la seconde valeur déterminée est de l'ordre de 180° ;
• le quatrième cylindre chauffant est de même diamètre que les trois premiers cylindres chauffants ;
• la machine comporte de plus un petit cylindre lisse d'axe parallèle à l'axe desdits cylindres chauffants, situé en aval des dits cylindres sur le trajet du carton ondulé et en dessous du plan horizontal tangent à la génératrice supérieure du quatrième cylindre ;
• la machine comporte des moyens de maintien de la distance entre les surfaces des deuxième et troisième cylindres, agencés pour supprimer toute pression du troisième cylindre sur les feuilles cannelées et de couverture de la feuille ondulée en contact avec le deuxième cylindre.

In advantageous embodiments, use is made of one and / or the other of the following arrangements:

• the first determined value is between around 30 ° and around 80 °;
• the first value is of the order of 60 °;
• the second determined value is between about 90 ° and about 200 °;
• the second determined value is of the order of 180 °;
• the fourth heating cylinder has the same diameter as the first three heating cylinders;
• the machine further comprises a small smooth cylinder with an axis parallel to the axis of said heating cylinders, located downstream of said cylinders on the path of the corrugated cardboard and below the horizontal plane tangent to the upper generatrix of the fourth cylinder;
• the machine comprises means for maintaining the distance between the surfaces of the second and third cylinders, arranged to remove any pressure from the third cylinder on the fluted sheets and for covering the corrugated sheet in contact with the second cylinder.

Such a system indeed gives results excellent even at unwinding speeds of the cardboard of 200 m / min.

The invention also provides a method of manufacturing using a machine as described above, and more particularly a method of making a single sheet of corrugated cardboard face, from a sheet of fluted cardboard and a flat sheet of cardboard, called a cover, by gluing one to the other, according to claim 10

• la première valeur déterminée est comprise entre de l'ordre de 30° et de l'ordre de 80° :
• la première valeur déterminée est de l'ordre de 60° :
• la seconde valeur déterminée est comprise entre de l'ordre de 90° et de l'ordre de 200° ;
• la seconde valeur déterminée est de l'ordre de 180° ;
• on règle la vitesse du cylindre lisse chauffant, à une vitesse comprise entre de l'ordre de 1,02 V et de l'ordre de 1,25 V , avantageusement 1,06 V, V étant la vitesse de défilement du carton ondulé formé ;

In advantageous embodiments, use is made of one and / or the other of the following arrangements:

• the first determined value is between around 30 ° and around 80 °:
• the first determined value is around 60 °:
• the second determined value is between about 90 ° and about 200 °;
• the second determined value is of the order of 180 °;
• the speed of the smooth heating cylinder is adjusted, at a speed of between about 1.02 V and about 1.25 V, advantageously 1.06 V, V being the running speed of the corrugated board formed ;

The invention will be better understood on reading the description of an embodiment of the invention given below by way of example not limiting.

• La figure 4 montre schématiquement un mode de réalisation de l'amélioration que constitue l'invention, en coupe transversale.
• La figure 5 est une coupe schématique selon V-V du quatrième cylindre de la figure 4.

The description refers to the accompanying drawings, in which, in addition to FIGS. 1 to 3, already described concerning a machine of the prior art:

• FIG. 4 schematically shows an embodiment of the improvement which the invention constitutes, in cross section.
• FIG. 5 is a diagrammatic section along VV of the fourth cylinder of FIG. 4.

The machine according to the embodiment of the invention more particularly described here comprises on the one hand a single-sided machine of the type described with reference to Figure 2, and secondly a fourth cylinder arranged like this is going to be described below with reference to Figure 4. To simplify, the same reference numbers are used when they refer to the same elements.

In addition to the first, second and third cylinder 12, 13 and 18 described with reference to the Figure 2, the machine according to the invention comprises a fourth cylinder 26 smooth, heating, axis 27, parallel to the axes of the previous cylinders and located above these, for example directly after the second cylinder on the path of the sheet of corrugated cardboard.

This cylinder is steam heated so similar for example to reach a temperature cylinder skin between 160 ° C and 200 ° C.

It is made of stainless steel and has for example a diameter identical to other.

Means (not shown) for adjusting the speed of rotation of the cylinder 26, known in themselves, are provided. The gear ratio cylinder 26 and cardboard scrolling is therefore adjustable to ensure the tension of the sheet cover which is rolled up and in contact with the smooth surface of the cylinder.

With a machine thus modified, bonding is different from classic collage. Instead of realizing the adhesive joint instantly by combined action heat and strong pressure, bonding is mainly provided by heat, the pressure being reduced significantly.

• une première zone de contact 28 entre la feuille cannelée 23 et la feuille de couverture 24, où les deux feuilles sont maintenues l'une contre l'autre sur le cylindre cannelé central 13 sur un angle d'enroulement α, par exemple d'environ 60°. Au point de jonction 29 des deux feuilles, l'espace entre le cylindre cannelé 13, central, et le troisième cylindre 18, lisse, presseur, est par ailleurs maintenu à une valeur fixe par des butées réglables, de façon à ce que la pression soit nulle ou faible, par exemple comprise entre 0 et 3 kg/cm, et ne détériore pas les feuilles ;
• une seconde zone de contact 30, où les deux feuilles sont à nouveau maintenues l'une contre l'autre mais cette fois-ci sur le cylindre 26 sur un angle d'enroulement β, par exemple de 180°, ce qui permet de compléter la gélatinisation et le séchage de la colle.

The glue dries in two areas:

• a first contact zone 28 between the corrugated sheet 23 and the cover sheet 24, where the two sheets are held against one another on the central corrugated cylinder 13 at a winding angle α, for example of approximately 60 °. At the junction 29 of the two sheets, the space between the central grooved cylinder 13 and the smooth, pressing third cylinder 18 is moreover kept at a fixed value by adjustable stops, so that the pressure either zero or weak, for example between 0 and 3 kg / cm, and does not damage the leaves;
• a second contact zone 30, where the two sheets are again held one against the other but this time on the cylinder 26 on a winding angle β, for example of 180 °, which makes it possible to complete gelatinization and drying of the glue.

Advantageously, V being the speed of cardboard scrolling, and V1 being the speed outside of cylinder 26, V1 is between around 1.02 V and around 1.25 V.

In the more embodiment particularly described here, and in order to maintain the corrugated sheet of fluted side, in contact with the grooved surface of cylinder 13 on an angle α, the cylinder 26 has at least by relation to the tangent plane at the point of contact 29 with the cylinder 13 part of its surface on the side of said cylinder 13.

To do this, the axis 27 of the cylinder 26 can also be located on the side of cylinder 13, for relative to the vertical plane passing through axis 31 of smooth cylinder 18.

To hold the sheet of corrugated cardboard, smooth side, in contact with cylinder 26 on a angle β, a small roller 32, smooth and full, known in itself, and suitable for being in contact with the sheet of corrugated cardboard, on the corrugated side, is by example provided.

To do this, it presents for example a lower generator 33 located below the plane horizontal 34 tangent to the upper generatrix of the cylinder 26.

Advantageously, the axis 35 of the cylinder 32 is located below the axis 27 of the cylinder 26.

Sufficient distances e and e 'between walls side, respectively of cylinders 13 and 26, and 26 and 32 are also provided to allow a smooth running of the formed cardboard sheet 36.

Figure 5 shows a schematic sectional view according to V-V of cylinder 26.

It includes two cylindrical ends 37 and 38 mounted on bearings 39, and a cylindrical body 40, for example made of stainless steel or cast iron, provided with a central recess 41 supplied with steam 42 by the end 37.

Steam circulates in the recess and is discharged at 43 via the same end 37. A motor with variable speed 44 allows you to vary the speed of rotation of cylinder 26 in known manner in itself, depending on the voltage sought for corrugated cardboard.

The smooth surface of the cylinder 26 allows possible slippages, allowing skating that catches any games.

Thanks to the invention, a significant improvement in characteristic of single-sided corrugated cardboard.

In particular and for example, it has been observed, all other things being equal, an improvement in the COBB humidity resistance of at least around 20%, and the burst strength of the 10% coverage, compared to a machine of the type from that of figure 2.

More generally, a device according to the invention retains the qualities of resistance to COBB humidity of the cover paper, without alterations, contrary to what is observed with the devices of the prior art.

Claims (16)

1. Machine (1) for the manufacture of a sheet (36) of single-faced corrugated cardboard by sticking a fluted sheet (23) of cardboard on to a flat liner sheet (24), comprising

   two heating cylinders substantially tangential in pairs, with parallel axes, namely a fluted first cylinder (12), for the preforming of the fluted sheet, and a central fluted second cylinder (13), provided with means for applying the fluted sheet against its periphery,

   means for pressing and flattening the flat sheet on to the flutings of the fluted sheet at the periphery of the said second cylinder, the said means being positioned so as to bring the flat sheet into contact with the flutings of the fluted sheet at the periphery of the second cylinder and to flatten the fluted sheet on to the second cylinder along a circular arc corresponding to an angle alpha at the centre with a first predetermined value, the said means for pressing and flattening comprising two cylinders, namely a third (18) and fourth (26) cylinders with axes parallel to the axes of the first and second cylinders,

   and means (19) for spreading adhesive over the said flutings before the said contact, characterised

   in that the third (18) and fourth (26) cylinders are heating and motor-driven cylinders,

   in that the third cylinder (18) is positioned so as to be in contact with the flat sheet (24) and so as to be, in operation, pressing on a line of contact (25) with the flutings of the second cylinder,

   in that the said third cylinder (18) is provided with means for regulating the said pressure of the flat sheet on the said line of contact with the flutings of the second cylinder, in operation, below a predetermined threshold value of 3 kg/cm, and

   in that the fourth cylinder (26) is smooth, located downstream from the second cylinder and is positioned so that it is itself in contact with the back of the flat sheet (24) over a circular arc corresponding to an angle beta at the centre having a second predetermined value.
2. Machine according to Claim 1, characterised in that it comprises means (44) for controlling and regulating the rotational speed of the said fourth cylinder with respect to the rotational speed of the said second cylinder.
3. Machine according to either of Claims 1 and 2, characterised in that the first predetermined value lies between a value of the order of 30° and one of the order of 80°.
4. Machine according to Claim 3, characterised in that the first predetermined value is of the order of 60°.
5. Machine according to any one of the preceding claims, characterised in that the second predetermined value lies between a value of the order of 90° and one of the order of 200°.
6. Machine according to Claim 5, characterised in that the second predetermined value is of the order of 180°.
7. Machine according to any one of the preceding claims, characterised in that the fourth heating cylinder (26) has the same diameter as that of the first three heating cylinders.
8. Machine according to any one of the preceding claims, characterised in that it also comprises a small smooth cylinder (32), with axis parallel to the axis of the said heating cylinders, located downstream from the said cylinders on the path of the corrugated cardboard and below the horizontal plane (34) tangential to the upper generator of the fourth cylinder.
9. Machine according to any one of the preceding claims, characterised in that the fourth cylinder comprises means (44) for regulating the rotational speed of the said fourth cylinder between a value of the order of 1.02 V and one of the order of 1.25 V, V being the speed of movement of the already formed corrugated cardboard.
10. Method for the manufacture of a sheet (36) of single-faced corrugated cardboard, from a sheet (23) of fluted cardboard and a flat sheet (24) of cardboard, called the liner, by sticking one on to the other, in which the peaks of the flutings of the corrugated sheet previously coated with adhesive are maintained in contact with the flat sheet over a first zone (28) formed by a first surface portion of a central fluted heating cylinder (13), called the second cylinder, over an arc corresponding to an angle at the centre having a first predetermined value,
    characterised in that

    before the said first portion and after spreading the adhesive, a linear pressure having a value below 3 kg/cm is applied to the second cylinder (13) by means of a heating and motor-driven press-cylinder, called the third cylinder (18), the said third cylinder being tangential to the said second cylinder and the said pressure being applied at the point of contact between the peaks of the flutings and the flat sheet (29), and

    after, and at a distance from, the said first portion, the sheet of fluted cardboard and the flat sheet are maintained in contact over a second zone (30) formed by a second surface portion of a smooth heating motor-driven rotating cylinder (26), called the fourth cylinder, located downstream from the central fluted cylinder (13) on the path of the corrugated cardboard, over an arc corresponding to an angle beta at the centre having a second predetermined value.
11. Method according to Claim 10, characterised in that the first predetermined value lies between a value of the order of 30° and one of the order of 80°.
12. Method according to Claim 11, characterised in that the first predetermined value is of the order of 60°.
13. Method according to any one of Claims 10 to 12, characterised in that the second predetermined value lies between a value of the order of 90° and one of the order of 200°.
14. Method according to Claim 13, characterised in that the second predetermined value is of the order of 180°.
15. Method according to any one of Claims 10 to 14, characterised in that the speed of the smooth fourth heating cylinder (26) is regulated at a speed lying between a value of the order of 1.02 V and one of the order of 1.25 V, V being the speed of movement of the already formed corrugated cardboard.
16. Method according to Claim 15, characterised in that the speed of the smooth fourth heating cylinder (26) is of the order of 1.06 V.

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