EP0794050A1 - Corrugated packaging material and machine and process for the manufacture of corrugated packaging material - Google Patents

Abstract

The packaging in wide longitudinal sheets is made of a reinforcing sheet (3) with saw tooth fluting and a cover sheet (2). To manufacture the reinforcing sheet a pressurised gas flow (6), from a compression chamber (4), is applied on the sheet surface to press it against a fluted support surface (5). A compression gutter (12), supplied with pressurised and humidified air (13), applies the cover sheet against the reinforcing sheet. Rollers (11) lead and guide the cover sheet to and from the gutter. A paster (8) coated with glue (10) assembles the cover and reinforcing sheets along one of their faces.

Description

The present invention relates to a packaging made of fluted material in large longitudinal plies, a process for the manufacture of this packaging and a machine for carrying out the process and manufacturing the product.

The present invention is particularly intended for the cardboard industry and cardboard packaging which can for example be used for the packaging of various manufactured products. It also concerns the machinery industry for the production of cardboard and packaging.

Cardboard packaging that can be used for packaging various manufactured products is already known and corrugated cardboard is a material widely used to make this type of packaging.

Corrugated cardboard generally consists of at least two elements. Praying is a cover sheet which is most often flat and made of paper. It makes it possible to give corrugated cardboard a substantially smooth external appearance.

The second component is a reinforcing sheet called a groove which is generally obtained by deformation of a flat sheet by making undulations. This reinforcement constitutes most of the thickness of the final material and gives it transverse rigidity.

The two sheets are joined by any means and most often by gluing. For example, an adhesive deposit is made on the top of the corrugations of one face of the reinforcing sheet and the covering sheet is applied to it to assemble them.

Devices and methods are known for the production of corrugated cardboard and packaging made of corrugated material.

It is for example known to shape the reinforcing sheet by placing it between two bearing surfaces having a wavy relief. By pressing these two surfaces on the sheet, a strong constraint is imposed on it and it is deformed to produce the undulations.

To implement this method, two cylinders are used which mesh and drive the sheet by deforming it. A corrugated reinforcing sheet is thus obtained. The cylinders are often large, for example a length of 2.5 meters in order to produce large sheets of corrugated cardboard. Investment in equipment is therefore heavy.

Corrugated material packaging has drawbacks.

One of their drawbacks is the limited number of shapes that can be made for the reinforcement sheet. Corrugated cardboard packaging is currently used very generally. Their profile is substantially sinusoidal and stepped. constant.

When making cardboard packaging, the sinusoidal profiles are not the most favorable forms for the optimal mechanical strength of the packaging. Thus, if the corrugated material is stressed in compression according to its thickness, the curved profile of the reinforcing sheet rapidly deforms and collapses under low loads. Likewise in bending, a corrugated cardboard plate does not have an optimal stiffness due to the rapid deformation of the corrugated profile.

Thus, packages made of current corrugated material have the drawback of not having optimum mechanical strength in compression and in bending.

In addition, the profiles of current materials require a significant consumption of paper. Indeed, a sinusoidal profile has a relatively long contour, from 2 to 6% longer for example than a sawtooth contour. The lengths of ply necessary for the manufacture of the reinforcing sheet are therefore greater. Paper consumption is a very sensitive point in the cardboard and cardboard packaging industry due to the amount of paper used. For example, lengths of 30,000 km of aquifers are commonly transformed there per year per machine.

In addition, the low resistance of current corrugated materials requires the use of thicker sheets of paper. As a result, the amount of raw material required is increased.

One of the consequences of this high consumption is the high cost price of current fluted material packaging.

The existing methods of manufacturing corrugated packaging and their implementation devices also have several drawbacks.

As described above, the methods of shaping the reinforcing sheet often use two bearing surfaces. There are therefore two solid-solid contacts on the sheet of paper. These contacts deteriorate the sheet and cause fractures which are detrimental to the strength and use of the packaging.

In the case where the bearing surfaces are meshing cylinders, these tend to crush the sheet under the action of a force perpendicular to its surface. On the other hand, the meshing of the grooves is done with a high friction, which subjects the sheet to a high lateral force. This effort tends to tear the sheet or to create incipient fractures.

Consequently, current methods and devices often result in an imprint and a degradation of the mechanical characteristics of the reinforcing sheet in the places where it has been deformed. A drawback is therefore the damage to the material during the formation of the reinforcing sheet.

Another drawback is the limited number of achievable groove shapes. The longitudinal grooves called grooves, which are machined on a cylinder, can have very different shapes. However, since it is necessary to use two meshing cylinders, the shapes of grooves allowing proper operation are limited to corrugated profiles with constant pitch. As a result, current methods and devices offer only few choices of groove shape.

Another disadvantage is the high cost of current devices. The reinforcement sheet is very generally formed by means of two fluted cylinders. They often have to meet demanding specifications.

On the one hand, the meshing requires very precise dimensions and adjustments and a significant surface hardness. Thus, the cylinders must often be made of steel and undergo heat treatments to increase their surface hardness. On the other hand, the profile of the cylinders must be slightly curved so that, during operation, the bearing force is well distributed along the cylinders and so that the contact with the sheet is well uniform.

These requirements induce a very heavy cylinder manufacturing cost. This is an important drawback which weighs on the cost price of packaging made of fluted material.

Another disadvantage is that the contact of the two cylinders quickly leads to their wear. Their lifespan is therefore limited. They should therefore be changed regularly, which leads to production stoppages. For example, in the corrugated cardboard industry, it is common to change the cylinders after processing 30,000 km of paper.

Another disadvantage is the delicate start-up and regular adjustments required by current devices.

The proper functioning of devices with two fluted cylinders is carried out under several conditions. The positioning of the cylinders must be very precise so that their axes are well parallel on the one hand and on the other hand so that the force applied to the sheet is constant.

The wear of the cylinders results in very frequent adjustments. They are also necessary to maintain a constant deformation quality. In practice, since the adjustments cannot be continuous, this consistency is not always achieved. Another disadvantage of two-cylinder machines is that it does not guarantee the production of cardboard of uniform quality over time.

The operation of such devices is very noisy. The cause is the rotation and meshing of the cylinders. Another disadvantage is therefore operating noise.

The rotation of the cylinders and the meshing also limit the production rates. Indeed, the vibrations generated by the operation of current machines do not allow very high speeds of rotation for the cylinders. Another drawback is therefore the limited manufacturing speed.

The packaging of fluted material packaged in large longitudinal layers, the method and the machine for the manufacture of packaging of fluted material, objects of the present invention, have many advantages.

The packaging described by the present invention is said to be fluted and non-corrugated material because the shapes of reinforcing sheets that can be produced are no longer limited to corrugations and may for example be sawtooth or slot profiles, possibly with a variable pitch.

One of the main aims of the invention is to produce a packaging made of fluted material having good mechanical strength.

A characteristic of the packaging made of fluted material described here is in fact to present a reinforcing sheet with substantially rectilinear groove shapes. Therefore, in the thickness direction, the reinforcing sheet has less tendency to bend than in the case of corrugated profiles existing so far.

In the particular case where the profile of the grooves is sawtooth, the packaging has the advantage of having good mechanical strength, especially in compression.

In the particular case where the profile of the grooves is in slots, the packaging has the advantage of having good rigidity. Another advantage of this profile is to offer a large contact surface between the reinforcing sheet and the cover sheet. Thus, the fluted material acquires a good cohesion which reinforces these mechanical characteristics.

Another object is to produce packaging made of fluted material whose cost price is low.

To do this, the present invention allows decrease the cost of raw material.

It has the advantage of being very resistant. As a result, it is possible to manufacture packaging that is as resistant as that currently existing with reduced paper thicknesses. By reducing the grammage of the paper, the costs are reduced.

In the particular case where the packaging of fluted material has a sawtooth profile, the consumption of paper is further reduced. Indeed, the triangular contour is very short compared in particular to that of the wavy profiles. A lower quantity of material is therefore necessary for its manufacture. Paper consumption can be reduced by creating a corrugated profile with variable pitch.

The corrugated cardboard packaging described here has the advantage of offering the user or the manufacturer the choice of the shape of the grooves according to the application envisaged for the packaging and no longer according to the manufacturing requirements.

The method and the machine for manufacturing fluted material packaging described by the present invention also have several advantages. The use of a single bearing surface has in particular interesting consequences.

One of the aims of the present invention is to propose a method and a machine making it possible to manufacture packaging made of fluted material, the flutes of which have very diverse shapes.

By using a single bearing surface, the present invention limits the form requirements linked to operation. We can therefore consider very diverse forms of grooves in particular sawtooth or slots, with variable pitch.

Another object of the present invention is to allow the manufacture of packaging made of fluted material with a reduced production cost.

The elimination of a support surface has the advantage of reducing the cost of purchasing equipment. If you use a support cylinder, you save the purchase of a cylinder first. Then, the manufacture of the cylinder will be less expensive than in the case of two meshing cylinders since the requirements of tolerances, adjustments, shapes and hardness are much lower.

Another advantage of the invention is that the life of the bearing surface is significantly increased. The elimination of the operation by solid-solid support greatly limits the wear of the support surface. Equipment renewal is therefore less frequent and limits the cost.

Another advantage is to allow the production of very varied groove shapes and in particular sawtooth with possibly a variable pitch in order to save raw materials. In addition, the proposed method does less damage to the material to be shaped. As a result, the sheet thicknesses can be small without the risk of tearing them. Thus, the mass of paper consumed is reduced.

Consequently, the installation, maintenance and raw material costs are reduced and make it possible to lower the cost price according to one of the aims of the present invention.

Another goal is to enable the production of better quality products.

The sheet to be deformed is no longer constrained between two bearing surfaces. As a result, it is less crushed and undergoes low lateral stresses. Thus, it is observed that the reinforcing sheet is less marked and has less incipient fractures in the area where it has been deformed. It also tears less often. One of the advantages of the invention is therefore to do little damage to the reinforcing sheet.

Another object is to reduce the operating noise of the device. By eliminating the solid-solid contact, in particular produced in the case of a gear with two fluted cylinders, noise pollution is greatly limited.

Another aim is to allow high production speeds. The vibrations and the resonance phenomena are very reduced by the absence of meshing and it is possible to use high production rates.

Another object of the invention is to lighten the design of machines for manufacturing corrugated cardboard packaging by eliminating a bearing surface.

Other objects and advantages will appear during the present description which is however given only for information.

The product which is the subject of the present invention relates to a packaging made of fluted material in large longitudinal plies consisting of at least one reinforcing sheet and a covering sheet, for example of paper, secured by one of their faces, intended for the production resistant packaging, particularly in compression and bending, characterized in that the profile of the reinforcing sheet consists of grooves with substantially rectilinear shapes such as saw teeth or slots made in the material of the sheet without damaging it and uniformly on the web for the production of resistant packaging products.

• on applique sur une face d'une feuille au moins un flux de gaz sous pression de façon à la plaquer sur une surface d'appui pour la déformer et réaliser la feuille de renfort,
• on solidarise par des moyens d'assemblage la feuille de renfort avec la feuille de couverture par l'une de leurs faces,

permettant de réaliser des emballages avec des cannelures de diverses formes.The process which is the subject of the present invention relates to a process for manufacturing a packaging made of fluted material consisting of at least one reinforcing sheet and a covering sheet secured by one of their faces, intended in particular for the manufacturing industry of cardboard packaging, characterized by the fact:

• at least one flow of gas under pressure is applied to one side of a sheet so as to press it onto a bearing surface to deform it and produce the reinforcing sheet,
• the reinforcing sheet is joined by assembly means to the cover sheet by one of their faces,

for packaging with grooves of various shapes.

• des moyens permettant d'appliquer sur une face d'une feuille au moins un flux de gaz sous pression de façon à la plaquer sur une surface d'appui pour la déformer et réaliser la feuille de renfort,
• des moyens d' assemblage permettant de solidariser la feuille de renfort avec la feuille de couverture par l'une de leurs faces,

permettant de réalise des emballages avec des cannelures de diverses formes.The machine which is the subject of the present invention relates to a machine for the manufacture of packaging made of fluted material consisting of at least one reinforcing sheet and one covering sheet, integral by one of their faces, intended in particular for the packaging industry. manufacture of cardboard packaging, characterized in that it has:

• means making it possible to apply at least one stream of pressurized gas to a face of a sheet so as to press it onto a bearing surface to deform it and produce the reinforcing sheet,
• assembly means making it possible to secure the reinforcement sheet with the cover sheet by one of their faces,

allowing packaging with grooves of various shapes.

Reading the figures in the appendix will facilitate understanding of the present invention.

Figure 1 illustrates a particular embodiment of the packaging in fluted material object of the present invention. The embodiment shown is that of sawtooth grooves.

Figure 2 shows schematically a second embodiment of the packaging in fluted material with grooves in slots.

FIG. 3 represents an example of packaging made of fluted material whose profile is variable along the reinforcement sheet.

Figure 4 shows a bearing surface consisting of a grooved cylinder and a compression chamber.

Figures 5 and 6 show schematically the manufacture of the packaging in fluted material according to particular embodiments of the invention.

The present invention relates to a packaging of fluted material (1) in large longitudinal layers, consisting of at least one reinforcing sheet (3) and a cover sheet (2), for example of paper, secured by one of their faces. .

The cover sheet (2) most often gives the packaging its external appearance. For example, it will be flat and smooth. The cover sheet (2) may be made of different materials, in particular paper. It may have variable dimensions.

The reinforcement sheet (3) constitutes most of the thickness of the packaging and gives it its rigidity. It can be made of different materials, especially paper. Its width, its length, its thickness can be variable.

The reinforcing sheet (3) has a relief which can take very diverse aspects. The profile of the grooves may nevertheless consist of substantially rectilinear edges to increase the mechanical strength of the packaging (1). The rising and falling sides of the reinforcing sheet (3) will be substantially rectilinear over a large part of their length. It is possible, for example, to produce a sawtooth profile, as illustrated in FIG. 1, or a notched profile, as illustrated in FIG. 2. The top of the grooves may not be straight and be bent.

Variable profiles can also be produced along the sheet by modifying the shape and distribution of the grooves: one can for example modify their spacing, their pitch, their height or their width. An example is shown in Figure 3.

The reinforcing sheet (3) and the covering sheet (2) are integral by one of their faces. This assembly can for example be constituted by a bonding line at the top of the grooves of the reinforcement sheet (3) in contact with the cover sheet (2).

The reinforcing sheet (3) does not show any deterioration of its material at the level of the grooves. It is in fact manufactured in such a way as to avoid marking and incipient fractures in deformed areas.

In the particular case where a regular profile is produced on the reinforcement sheet (3), for example sawtooth or in slots, this profile is produced uniformly along the reinforcement sheet, ie with a constant shape and dimensions of grooves.

The present invention also relates to a method and a machine for manufacturing packaging made of fluted material.

One of the characteristics of the machine described here is to have a single bearing surface (5). This surface can be made of various materials, in particular of steel, and can come in a variety of shapes and sizes. We can, in the particular mode illustrated in Figure 4, achieve it with a cylinder (5) of fluted steel on its periphery. The grooves are in this case hollow longitudinal grooves in the steel. They can be presented in various aspects, in particular with a sawtooth, square or wavy profile.

The machine also has means (4) for applying a flow of gas (6) under pressure on one face of the sheet to be shaped. Their number, shape, size and material are not limited.

In a particular embodiment, these means are a compression chamber (4). This chamber (4) may be made of steel and comprise at least two parts: a gas inlet and a part allowing the application of the flux. It will be designed to direct the flow towards the chosen application area with the desired pressure. A temple for making the chamber (4) is shown in FIG. 4.

In a particular embodiment of the invention, the chamber (4) comprises means for humidifying the gas. These means can be constituted by any known device.

In another particular embodiment, the compression chamber (4) comprises means for preheating the gas. We can for example perform preheating using a heating resistance system or a steam injection.

The production of fluted material packaging requires assembly means. Bonding may in particular be used.

According to the embodiments of the invention illustrated in FIGS. 5 and 6, use is made of a glue (8) of common design and of glue (10) which coats the glue (8).

Figure 5 shows schematically the case where the cover (2) is applied to the reinforcement sheet (3) by means of a smooth press (9).

According to the embodiment shown in Figure 6, the application of the cover sheet (2) on the reinforcement sheet (3) is effected by means of a compression gutter (12). This gutter (12) will have variable shapes and dimensions. It will preferably be made to adapt to the shape of the support surface (5).

Its operation is substantially equivalent to that of the compression chamber (4). It in fact comprises a gas inlet and a part allowing this pressurized gas (13) to be applied, in particular possibly heated and humidified air or water vapor, to the surface of the cover (2).

The fluid pressure coming from the gutter (12) makes it possible to press the cover sheet (2) on the reinforcement sheet (3) to assemble them.

Rollers (11) can be used to bring, by guiding it, the cover sheet (2) towards the gutter (12) and to evacuate, by guiding it, the packaging made of fluted material (1) manufactured.

In a particular embodiment, the machine for manufacturing packaging made of fluted material has drive means (7) making it possible to bring the sheet onto the bearing surface (5).

One can for example use drive rollers (7). These rollers (7) are parallel and are placed facing each other on the sheet. They are driven by their own rotation by any means of motorization in order to be able to rotate in opposite directions and carry the sheet placed between them. They apply light pressure to the sheet so as not to damage it.

In a particular embodiment, these rollers (7) are grooved and mesh with one another in order to carry out a pre-shaping of the sheet.

The present invention also uses a flow of gas (6) under pressure. Different gases can be used and in particular compressed air or steam. The surface of application of the flow and the pressure of the gas are not limited but will often remain unimportant.

The process and the machine for manufacturing fluted material packaging are implemented in several stages. It is here chosen to describe the mode particular embodiment of the invention where the bearing surface is a cylinder (5) and where the means for applying the flow of gas (6) under pressure are constituted by a compression chamber (4) according to the illustration of Figure 4.

The sheet to be shaped (3) is first brought to the cylinder (5). To do this, rollers (7) can be used as illustrated in FIG. 5. Once the sheet in position, a flow of pressurized gas (6) coming from the compression chamber (4) is applied to one face of the sheet (3).

The gas flow (6) exerts a pressure which presses the sheet on the cylinder (5). The sheet then tends to follow the shape of the outline of the cylinder (5). The flow (6) and the reaction force of the cylinder (5) impose a deformation on the sheet (3). The reinforcing sheet (3) is thus produced and its shape is determined by the relief of the support cylinder (5).

To achieve continuous production, the support cylinder (5) can rotate to continue shaping along the sheet (3) and to bring the reinforcing sheet (3) to the assembly means.

It is then possible to join the reinforcing sheet (3) and the cover sheet (2). In the case of an assembly by gluing, FIG. 5 illustrates that glue (10) can be deposited on the raised surfaces of one face of the reinforcing sheet (3) by means of a glue (8). You can then apply the cover sheet (2).

This application can be done by means of a press (9) which brings the cover sheet and puts it in contact, by exerting significant pressure, with the reinforcement sheet (3).

In another embodiment of the invention, the pressurized gas (13) presses the cover sheet (2) on the reinforcement sheet (3). This pressurized gas is applied by means of a gutter (12) placed near the bearing surface. The gutter (12) compresses the sheet (2) on the sheet (3) to a pressure sufficient for the contact of the two sheets to be important.

In another particular embodiment, this pressurized gas (13), for example steam, is heated and humidified to promote the bonding of the cover (2) and reinforcement (3) sheets.

After a drying time, a package of fluted material (1) is obtained, the constituent parts of which are integral.

Depending on the nature of the fluted material, it may be necessary to preheat or humidify the reinforcing sheet (3) and the sheet (2) to allow shaping or assembly.

The heat supply or the humidification can be carried out via the gas flow (6) and (13).

This is why a particular embodiment of the invention comprises means for preheating the gas flow (6) and (13) making it possible to heat the reinforcing sheet (3) at the time of its shaping and the sheet ( 2) at the time of bonding.

In another particular embodiment of the invention, means make it possible to humidify the flow of pressurized gas (6) and (13) in order to provide a supply of moisture for the reinforcing sheet (3) and the sheet cover (2).

Claims (10)

Packaging of fluted material (1) in large longitudinal layers, consisting of at least one reinforcing sheet (3) and a cover sheet (2), for example of paper, joined by one of their faces, intended for the production of resistant packaging, particularly in compression and bending, characterized in that the profile of the reinforcing sheet consists of grooves with substantially rectilinear shapes such as saw teeth or slots made in the material of the sheet (3) without damage it evenly on the tablecloth for the manufacture of resistant packaging products. Method for manufacturing a packaging of fluted material (1) consisting of at least one reinforcing sheet (3) and a cover sheet (2), integral by one of their faces, intended in particular for the industry of manufacture of cardboard packaging, characterized by the fact: - at least one flow of pressurized gas (6) is applied to one side of a sheet so as to press it onto a bearing surface (5) to deform it and produce the reinforcing sheet (3), - that the reinforcing sheet (3) is joined by means of assembly to the cover sheet (2) by one of their faces, for packaging with grooves of various shapes. Machine for the manufacture of packaging made of fluted material consisting of at least one reinforcing sheet (3) and one covering sheet (2), integral by one of their faces, intended in particular for the manufacturing industry cardboard packaging, characterized by the fact that it has: - Means (4) making it possible to apply at least one stream of pressurized gas (6) to one face of a sheet so as to press it onto a bearing surface (5) to deform it and produce the sheet of reinforcement (3), assembly means making it possible to secure the reinforcing sheet (3) with the cover sheet (2) by one of their faces, for packaging with grooves of various shapes. Machine for the manufacture of packaging made of fluted material (1) consisting of at least one reinforcement sheet (3) and a cover sheet (2), integral by one of their faces, intended in particular for the industry of manufacture of cardboard packaging according to claim 3, characterized in that it has drive means (7) making it possible to bring the sheet (3) onto the bearing surface (5). Machine for the manufacture of packaging made of fluted material (1) consisting of at least one reinforcement sheet (3) and a cover sheet (2), integral by one of their faces, intended in particular for the industry of manufacture of cardboard packaging according to claim 4, characterized in that the drive means (7) enabling the sheet (3) to be brought to the bearing surface (5) consist of at least two rollers parallel. Machine for the manufacture of packaging made of fluted material (1) consists of at least one reinforcement sheet (3) and a cover sheet (2), integral by one of their faces, intended in particular for the industry of manufacture of cardboard packaging according to claim 3, characterized in that the bearing surface (5) consists of the peripheral surface of a cylinder whose profile is that desired for the reinforcing sheet (3). Machine for the manufacture of packaging made of fluted material (1) consisting of at least one reinforcement sheet (3) and a cover sheet (2), integral by one of their faces, intended in particular for the industry of manufacture of cardboard packaging according to claim 3, characterized in that the means (4) making it possible to apply at least one flow of pressurized gas (6) to one face of a sheet are constituted by a compression. Machine for the manufacture of packaging made of fluted material (1) consisting of at least one reinforcement sheet (3) and a cover sheet (2), integral by one of their faces, intended in particular for the industry of manufacture of cardboard packaging according to claim 7, characterized in that the compression chamber (4) has means for humidifying the pressurized gas to be applied to the sheet to facilitate the shaping of the sheet. Machine for the manufacture of packaging made of fluted material (1) consisting of at least one reinforcement sheet (3) and a cover sheet (2), integral by one of their faces, intended in particular for the industry of manufacture of cardboard packaging, according to claim 7, characterized in that the compression chamber (4) has means for heating the gas under pressure to be applied to the sheet (3) to produce a thermal contribution on the sheet. Machine for the manufacture of packaging made of fluted material (1) consisting of at least one reinforcement sheet (3) and a cover sheet (2), integral by one of their faces, intended in particular for the industry of manufacture of cardboard packaging, according to claim 3, characterized in that the assembly means making it possible to secure the reinforcement sheet (3) with the cover sheet (2) by one of their faces, comprise a compression gutter (12) which applies a pressurized gas (13) to one face of the cover sheet (2) to press it onto the reinforcement sheet (3) in order to secure them.

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