CN110614835A - Pressure roller and method, composite packaging material, packaging sheet and packaging container - Google Patents

Abstract

The present invention provides a pressure roller and a method for manufacturing laminated packaging material, and a composite packaging material, a packaging sheet and a packaging container manufactured thereby. The pressure roller is arranged on a composite production line of the laminated packaging material, the pressure roller and a cooling roller which is also arranged on the production line are arranged in pairs, the semi-finished packaging material which is pre-provided with pre-pressing holes passes through a squeezing roller gap between a roller group consisting of the pressure roller and the cooling roller, the outermost layer of the pressure roller is made of polymer elastic material, and a plurality of discontinuous grooves are arranged on each circumferential area corresponding to the positions of the pre-pressing holes on the outermost layer of the pressure roller. The technical scheme of the invention can obviously improve the reliable opening performance and the transportation stacking stability of the composite packaging material, the packaging sheet and the packaging container.

Description

Pressure roller and method, composite packaging material, packaging sheet and packaging container

Technical Field

The present invention relates to the technical field of opening devices on packaging materials, and particularly to a pressure roller and a method for manufacturing laminated packaging materials, and a composite packaging material, a packaging sheet and a packaging container manufactured by the same.

Background

Single-use, disposable packaging containers for liquid food products such as milk, dairy products, non-carbonated beverages, fruit juices, purees and the like are usually produced from a packaging laminate comprising a bulk core layer of paper or paperboard and a liquid-tight layer of thermoplastic. In order to render the packaging containers light-and gas-tight, in particular oxygen-tight, for aseptic packaging, the laminate material used for these packaging containers is usually provided with at least one metal foil layer, most commonly an aluminium foil. The aluminium foil makes the packaging material heat-sealable by induction heat-sealing, which is a fast and effective sealing technique to obtain a mechanically strong, liquid and gas tight sealing joint or seam during the production of the container. As shown in fig. 1, a common layer structure of a packaging laminate is as follows: the core layer 12 of paperboard is covered with a layer of low density polyethylene plastic to form the outermost layer 11 of the packaging laminate, i.e. the side of the finished package not in contact with the enclosed product. The inner side of the paperboard core layer 12 is covered with a similar low density polyethylene layer for laminating a thin aluminum foil layer 14 to the paperboard core layer 12, herein referred to as core adhesive layer 13. To avoid contact between the encapsulated product and the aluminium foil, the aluminium foil layer 14 is covered by a polymer layer, herein referred to as inner adhesive layer 15. The inner adhesive layer 15 is in turn covered by an innermost layer 16 of low density polyethylene or a blend of low density polyethylene and linear low density polyethylene, which innermost layer 16 will be in direct contact with the encapsulated product in the packaging container, which innermost layer 16 typically has sufficient properties for heat sealing and for acting as a moisture barrier against the encapsulated product filled in the package.

In the manufacture of laminated packaging material, as shown in fig. 2, it is common to start with a paperboard web, on both sides of which different types of film or foil layers are laminated to obtain the desired properties of the finished packaging material. Paperboard webs are typically delivered in roll form. A paperboard roll is applied to one end of a laminating machine which includes a plurality of rollers which together form a wrapper path. To achieve the pressure necessary for lamination, the pressure roll and the cooling roll at lamination are usually placed close to each other, forming a press nip between the two rolls. When the web of composite layers is passed through a press nip under lamination conditions, the layers are pressed to adhere to one another by means of a pressure roll and a cooling roll. The extent of the press nip in the axial direction of the web is determined on the one hand by the pressure between the pressure roller and the cooling roller and on the other hand by the elasticity/hardness of the material of the pressure roller and the cooling roller. This means that the pressure roller may have a slightly convex shape, which compensates for the outward flexing of the rollers and exerts a uniform pressure over the entire width of the rollers at a certain pressure between the rollers. The application of the polymer layer in laminates is usually carried out by extrusion coating or extrusion lamination of molten thermoplastic polymers. In an extrusion lamination operation, the core adhesive layer 13 is extruded from the laminating machine in the form of a molten curtain applied between the paperboard web and the aluminum foil web as they enter the press nip or applied to the paperboard web just before the press nip. In an extrusion coating operation, the innermost layer 16 is extruded from the laminating machine together with the inner adhesive layer 15 in the form of a molten curtain applied to the laminated web of paperboard 12, core adhesive layer 13 and aluminum foil 14 as they enter the press nip. The temperature of the molten polymer curtain when applied to the aluminum foil 14 is quite high, in the range of 200 c to 350 c, and its density changes by at least 10% when the molten film solidifies to form the adhesive layer. This does not normally cause any problems, since the main part of the aluminium foil is supported by the more dimensionally stable cardboard web.

In the process of wrapping a product with a laminated packaging material, the packaging container is usually produced by a filling machine which forms, fills and seals the package from a web or sheet. The production of packaging containers from a web is carried out by joining two longitudinal edges of the web to each other in such a way that they overlap to form a continuous tube. The tube is filled with the liquid food product and is divided into individual packages by repeated transverse sealing of the tube at a distance from each other below the level of the contents of the tube. The packages are separated from the tube by transverse cuts at transverse sealing sites and given the desired geometry by fold formation along pre-stressed crease lines in the packaging material.

From the point of view of the consumer, it is desirable that the packaging container is easy to handle and easy to open when the enclosed product is to be drunk or emptied, and to meet this requirement, the packaging container is usually provided with some type of opening device by means of which the package can be opened easily without the need to use scissors or other tools. Opening devices which are commonly present in packaging containers comprise a hole punched in a packaging core layer, the pre-punched hole being covered on the inside and outside of the packaging core layer by other layers of the packaging which are sealed to each other in the area of the opening contour of the pre-punched hole, thereby forming a film without paperboard. For smaller volume containers, the Pre-Punched holes are straw holes, with smaller diameters, commonly referred to as Pre-Punched holes (PPH). For larger volume containers, the Pre-punched holes have a larger pore size, commonly referred to as Pre-punched holes (PLH). At the punching press hole region in advance, for punching a hole in advance, for the packing integrality in the transportation, the pre-compaction hole has higher requirement to the intensity of polyethylene layer and aluminium foil, and for the lid convenience of opening, the pre-compaction hole has higher requirement to the interlaminar viscous force of polyethylene layer and aluminium foil, and for gas, water barrier property, the pre-compaction hole has higher requirement to the barrier property of polyethylene layer and aluminium foil.

An opening device has a separate pull tab or easy-open sticker which is applied over the pre-pressure hole and is sealed rupturably to the outermost layer of the package along a sealing joint around the entire opening contour of the pre-pressure hole and at the same time permanently to the aluminium foil and the inner layer in the region inside the opening contour of the pre-pressure hole. In another opening device, an opening device, usually made of moulded plastic, having a pouring spout and a screw cap for resealing, is applied to the pre-stressed hole and the area around it, which penetrates or removes the hole membrane in the area of the pre-stressed hole by a pushing-down and/or screwing action or removes the hole membrane by a screwing-up and/or pulling-up action. A prerequisite for the above-described opening device to function effectively and conveniently is that there is sufficient adhesion between the different layers of the apertured film, in particular between the aluminium foil and the layers of the laminate, so that the pull-tab or easy-open sticker can be torn off following the opening operation during the opening operation and ensures that the plastic layers and the aluminium foil are torn off simultaneously, or that the apertured film does not delaminate when a screwing and/or pulling force or a screwing and/or pushing force is applied to the apertured film.

Two key problems exist with the pre-perforated region of the packaging material. One key issue is interlayer adhesion. When laminating together an aluminium foil and a thermoplastic layer, it is often difficult to obtain sufficient adhesion in the area of the pre-pressed hole, due to the difference in total lamination thickness between the area of the pre-pressed hole and the area outside the pre-pressed hole. When the opening device is opened, sudden ruptures may occur between the aluminium foil and the innermost layer, and between the aluminium foil and the inner adhesive layer, due to the rotating and/or pulling action of the apertured film, with the result that part of the apertured film remains covering the pre-stressed aperture, preventing the packaged product in the package from pouring out. This problem may also exist in insufficient bonding between the aluminium foil and the core adhesive layer. The main reason is that the aluminum foil forming the oxygen barrier layer is generally very thin, in the range of about 5 to 10 μm. Thus, when laminating the core adhesive layer and the inner adhesive layer, the innermost layer, to the aluminium foil, the aluminium foil is rather fragile and may cause some problems. When the aluminum foil is laminated to the edge around the pre-pressure hole in the body core layer by the pressure roller and is partially pressed into the pre-pressure hole, there is a risk that the aluminum foil is broken since the pre-pressure hole has a relatively sharp edge, and thus the adhesion with the body core layer may be deteriorated in the edge region of the pre-pressure hole. Some problems arise from poor adhesion between adjacent layers; uneven application of the core and inner adhesive layers, the innermost layer; defects such as minute pinholes in the composite layer, and the like. Due to the tension in the aluminium foil that is formed during lamination, there may be a fracture of the aluminium foil in the area near the pre-pressing hole of the paperboard core layer. When the pre-stressed aluminum foil material is subjected to further stress, fractures in the aluminum foil may first occur during subsequent handling in a filling machine or during distribution and transportation. The rupture of the aluminium foil results in an insufficient tightness of the package. Thus, such problems may be more pronounced when there are pre-embossed holes in the paperboard core layer instead of a completely flat, uniform thickness layer. Another reason is that the aluminium foil is unsupported in the area of the pre-embossed holes of the cardboard web. Since the unsupported aluminum foil of the paperboard web is hot in the areas applied, when the polymer cools and solidifies around the edges of the pre-press holes, tension may be present in the aluminum foil due to polymer shrinkage, especially during high speed processes, which may result in tension being included in the layer of aluminum foil in the final laminate of melt extrusion lamination or extrusion coating of the aluminum foil with adjacent layers. In the area defined by the pre-punched holes, due to the difference in pore size, a press nip suitable for pre-punching often cannot press the aluminium foil and the polymer layer together sufficiently at the pre-punched holes to obtain the necessary adhesion.

Another key problem is air entrapment between the layers. The thickness variation of the core layer may result in that the thinner aluminium foil is not sufficiently pressed and bonded to the surrounding layer of thermoplastic material throughout the area defined by the pre-pressed hole, which means that the edges adjacent to the pre-pressed hole may be embedded with air. This in turn means that there may be crack formation in the aluminium foil which may lead to impaired air tightness of the packaging container and thus to impaired colour, taste and nutritional value of the packaged food product. Furthermore, the integrity of the package may be compromised, which in turn may interfere with the sterility of the package. Air inclusions also result in difficulties in tearing or piercing the film of the hole formed by the aluminum foil and the polymer film in the pre-pressed hole, limiting the ability to open the package and/or failing to produce a clean cut upon piercing, resulting in the formation of burrs.

One solution to increase the adhesion between the aluminium foil and the other layers in the area of the pre-stressed hole and to reduce the air inclusions between the layers is to reduce the web speed, but this is not suitable from a production economics point of view. There is therefore a need for an improved, more stable solution for manufacturing laminated packaging materials, allowing to provide laminated packaging materials with reliable adhesion in high speed lamination composite processes and in difficult to handle areas of the laminated material and between thin and sensitive laminate layers. It is particularly desirable to avoid and minimize the formation of tension or air pockets around the pre-stressed hole area of the paperboard. In particular, the laminated aluminium foil and the polymer layer in the area of the pre-pressed holes of the cardboard should have good adhesion over the whole area of the hole film or pre-pressed holes, and the hole film should have as few defects as possible, such as tension in the aluminium foil, air residues, cracks or pinholes in the layer, uneven thickness of the polymer layer, etc.

Disclosure of Invention

The main object of the present invention is to provide a pressure roller and a method for manufacturing laminated packaging material as well as a composite packaging material, a packaging sheet and a packaging container manufactured therefrom. The technical scheme of the invention enhances the interlayer bonding performance of the prepressing hole area on the composite packaging material.

According to a first aspect of the present invention, there is provided a pressure roller for manufacturing laminated packaging material, provided on a composite production line of laminated packaging material, the pressure roller being provided in pair with a cooling roller also provided on the production line, a semi-finished packaging material previously provided with pre-press holes being passed through a press nip between the pressure roller and the set of rollers consisting of the cooling roller, the outermost layer of the pressure roller being of a polymeric elastic material, characterized in that a plurality of discontinuous grooves are provided on each circumferential region of the outermost layer of the pressure roller corresponding to the position of the pre-press holes.

According to a preferred embodiment of the present invention, the grooves are a left and right row of groove sequences, each groove in the left groove sequence is inclined to the left at an angle to the direction of the pinch nip, and each groove in the right groove sequence is inclined to the right at the same angle to the direction of the pinch nip.

According to a preferred embodiment of the present invention, each groove crosses a circumference where a center of the pre-pressing hole is located, an inner end of each groove is close to the circumference where the center of the pre-pressing hole is located, an outer end of each groove exceeds a maximum edge of the pre-pressing hole in the axial direction of the pressure roller, and an outer end is close to the maximum edge of the pre-pressing hole in the axial direction of the pressure roller, the inner end being forward of the outer end in the rotational direction of the pressure roller.

According to a preferred embodiment of the present invention, the left and right oblique included angles range from 30 ° to 60 °.

According to a preferred embodiment of the invention, the grooves are discrete but evenly distributed grooves.

According to a preferred embodiment of the invention, the grooves are a plurality of rows of interrupted groove sequences arranged equidistantly, the groove discontinuities in two adjacent rows of groove sequences being non-aligned.

According to a preferred embodiment of the present invention, the groove shapes include, but are not limited to, stripes, circles, irregular patterns, ovals, squares, triangles, wave patterns.

According to a second aspect of the present invention, a method for manufacturing laminated packaging material is provided, characterized in that at least one compounding position of a compounding line of laminated packaging material is provided with the aforementioned pressure roller, which is arranged in pairs with a cooling roller in the compounding position, and that a semi-finished packaging material, which is pre-provided with pre-pressed holes, is passed through a press nip between the pressure roller and the set of cooling rollers.

According to a preferred embodiment of the invention, the method comprises a first step wherein laminating the composite core adhesive layer with the aluminium foil layer on the paperboard core layer is performed at a first compounding location.

According to a preferred embodiment of the invention, step one is followed by step two, wherein lamination of the composite inner adhesive layer with the innermost layer on the aluminium foil layer is performed at a second compounding location.

According to a preferred embodiment of the invention, step three is included before step one or between step one and step two or after step two, wherein laminating the composite outermost layer on the paperboard core layer is performed at a third composite location.

According to a third aspect of the present invention there is provided a composite packaging material manufactured using the aforementioned pressure roller or using the aforementioned method, the composite packaging material being used to form packaging containers.

According to a fourth aspect of the present invention there is provided a packaging sheet made from the aforementioned composite packaging material, each packaging sheet being for forming an individual packaging container.

According to a fifth aspect of the present invention, there is provided a packaging container formed from the aforementioned composite packaging material or the aforementioned packaging sheet.

Compared with the prior art, the technical scheme of the invention improves the outermost layer of the pressure roller, and obviously overcomes the defects of interlayer adhesion and air inclusion between layers in the prepressing hole area of the packaging material. The composite packaging material, packaging sheet and packaging container produced by the pressure roller and method for producing laminated packaging material of the present invention have significantly improved reliable opening performance and shipping stacking stability.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a schematic view of a prior art layer of packaging material;

FIG. 2 is a schematic view of a prior art packaging material lamination compounding apparatus;

FIG. 3 is a schematic view of a pressure roll-chill roll according to an embodiment of the invention;

FIG. 4 is a schematic view of the outermost ply of a pressure roller being laid flat according to one embodiment of the invention;

FIG. 5 is a schematic view of the outermost ply of a pressure roller being laid flat according to one embodiment of the invention;

FIG. 6 is a schematic view of the outermost ply of a pressure roller being laid flat according to one embodiment of the invention.

In the drawings, the same reference numerals are used to designate the same or similar components.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

In the following description, references to "one embodiment," "an embodiment," "one example," "an example," etc., indicate that the embodiment or example so described may include a particular feature, structure, characteristic, property, element, or limitation, but every embodiment or example does not necessarily include the particular feature, structure, characteristic, property, element, or limitation. Moreover, repeated use of the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may.

Certain features that are well known to those skilled in the art have been omitted from the following description for the sake of simplicity.

Figure 3 schematically shows a set of pressure rollers 21, 23, 25 and cooling rollers 22, 24, 26 in three compound positions in a line for manufacturing laminated packaging material. The web material with pre-pressed holes passes in sequence between three pairs of pressure rollers and cooling rollers, the dotted lines on the pressure rollers indicating the areas corresponding to the pre-pressed holes on the web material.

Example 1

Lamination of the composite core adhesive layer 13 with the aluminium foil layer 14 on the paperboard core layer 12 is performed at a compounding position comprising a pressure roll 21 and a cooling roll 22. The paperboard core layer 12 or a composite layer comprising the paperboard core layer 12 is contacted with a pressure roll 21, the aluminum foil layer 14 is contacted with a cooling roll 22, and the molten curtain of core adhesive layer 13 is first poured onto the side of the paperboard core layer 12 not contacted with the pressure roll 21 and then laminated together with the paperboard core layer 12 and the aluminum foil layer 14 into the pressure nip between the pressure roll 21 and the cooling roll 22.

The chill roll 22 is typically a smooth surfaced metal roll. The outer diameter of the pressure roller 21 ranges from 200 mm to 400 mm. The width of the pressure roll 21 is slightly wider than the width of the paperboard core layer 12, typically 1050 mm to 1350 mm. The maximum circumferential linear speed of the pressure roller 21 can reach 300 m/min-800 m/min. The outermost layer of the pressure roller 21 is a polymer elastic material, preferably polyurethane or rubber. The range of the Shore A hardness value of the outermost layer of the pressure roller 21 is 80-90. The outermost layer of the pressure roller 21 is deformed under pressure, and when the paperboard core layer 12 having a thickness of generally 300 to 500 μm passes through the press nip, the distance between the pressure roller 21 and the cooling roller 22 is adjusted according to the thickness, thereby adjusting the pressing force such that the length of the press nip ranges from 20 to 40 mm. The outermost layer of the pressure roller 21 can penetrate or protrude into the pre-embossed holes of the paperboard core layer 12 when the area of the pre-embossed holes in the packaging material passes the press nip. The diameter or equivalent diameter of the pre-pressing hole ranges from 15 mm to 30 mm.

Since the circumference of the pressure roller 21 is not necessarily proportional to the length of the corresponding unit of each package on the web, and since the pressure of the pressure nip and the deformation are adjustable, the location of the pressure roller 21 in contact with the pre-perforated area is determined in the axial direction of the pressure roller 21, but is not determined in the circumference. That is, the entire circumference of the pressure roller 21 corresponding to the lateral position of the pre-pressure hole may be in contact with the pre-pressure hole.

A coiled material is generally transversely arranged in parallel for 4-7 rows to be cut into sub-coiled materials for loading on a filling machine in the future, the width of each sub-coiled material is the width of a unit corresponding to each packing box, so that the circumference of the transverse position of the corresponding prepressing hole on the pressure roller 21 is correspondingly 4-7, and the distance between the adjacent circumferences is also the width of the corresponding unit of each packing box. Each of fig. 3 to 6 is schematically shown as 4.

As shown in fig. 4, two rows of groove sequences are provided on the circumference of the pressure roller 21 corresponding to the position of the pre-press hole. Every recess in the left recess sequence is certain contained angle and extrudees the roll gap direction and inclines to the left, and every recess is crossed pre-compaction hole centre of a circle place circumference, and the inner of every recess is close pre-compaction hole centre of a circle place circumference, and the outer end of every recess surpasss the biggest edge of pre-compaction hole at pressure roller 21 axial to the outer end is close the biggest edge of pre-compaction hole at pressure roller 21 axial, and in pressure roller 21 direction of rotation, the inner is in outer end the place ahead, also the inner contacts the coiled material earlier than the outer end in the extrusion roll gap. Every recess in the right side recess sequence is the same contained angle with extrusion roll gap direction and inclines right, and every recess is crossed pre-compaction hole centre of a circle place circumference, and the inner of every recess is close pre-compaction hole centre of a circle place circumference, and the outer end of every recess surpasss the biggest edge of pre-compaction hole at pressure roller 21 axial to the outer end is close the biggest edge of pre-compaction hole at pressure roller 21 axial, and in pressure roller 21 direction of rotation, the inner is in outer end the place ahead, just also the inner contacts the coiled material earlier than the outer end in the extrusion roll gap. The left and right included angles are in the range of 30 ° to 60 °, preferably 45 °. The grooves in the left groove sequence are arranged at equal intervals, the grooves in the right groove sequence are also arranged at equal intervals, the grooves in the two groove sequences are arranged in a staggered mode, and the grooves in the two groove sequences are not intersected with each other. The width, depth and length of the groove can be flexibly set according to the diameter and hardness of the pressure roller 21 and the size of the prepressing hole, and the groove is preferably 1-3 mm wide and 2-4 mm deep.

Since the pressure roller 21 is of an elastomeric material when the web passes through the press nip, the pressure roller 21 is partially pressed into the pre-press holes as the pre-press holes pass through the press nip, and interacts with the cooling roller 22 in the area of the pre-press holes to laminate the paperboard core layer 12 with the core adhesive layer 13 and the aluminum foil layer 14. The sequence of two rows of grooves also creates a slight deformation in the press nip, releasing the stress in the aluminium foil in the direction perpendicular to each groove, allowing the paperboard core layer 12, the core adhesive layer 13 and the aluminium foil layer 14 to adhere sufficiently. And each groove is designed to extend in the rotational direction of the pressure roller 21 out of the pre-pressure hole so that air trapped between the layers can be squeezed out.

Example 2

Lamination of the composite inner adhesive layer 15 with the innermost layer 16 on the aluminium foil layer 14 is performed at a composite position comprising a pressure roll 23 and a cooling roll 24. The aluminium foil layer 14 has now been laminated with the paperboard core layer 12 via the core adhesive layer 13. If defined before and after the lamination compounding process, the compounding position including the pressure roller 23 and the cooling roller 24 must be performed after the compounding position including the pressure roller 21 and the cooling roller 22, that is, the lamination of the composite inner adhesive layer 15 and the innermost layer 16 on the aluminum foil layer 14 must be performed after the lamination of the composite core adhesive layer 13 and the aluminum foil layer 14 on the paperboard core layer 12. The composite of paperboard core layer 12, core adhesive layer 13, and aluminum foil layer 14 is in contact with pressure roller 23. The molten curtain of inner adhesive layer 15 and innermost layer 16 is first poured onto a chill roll 24 and then laminated with the composite of paperboard core layer 12, core adhesive layer 13, and aluminum foil layer 14 into a pressure nip between pressure roll 23 and chill roll 24.

As shown in fig. 5, a plurality of rows of concave holes (cylindrical grooves) are provided on the circumference of the pressure roller 23 corresponding to the position of the pre-press hole. In order to ensure uniformity, the positions of the concave holes in each row in the axial direction of the pressure roller 23 are consistent, the concave holes in each row are arranged at equal intervals, the distance between two adjacent rows of concave holes is the same, and the positions of the concave holes in each row in the circumferential direction are staggered. Of course, the recesses may not be arranged in rows, but may be distributed in any discrete manner, as long as a uniform distribution in the area of the pre-pressed holes is ensured. The diameter and the depth of the concave hole can be flexibly set according to the diameter and the hardness of the pressure roller 23 and the size of the prepressing hole, and preferably the diameter of the concave hole is 1-3 mm, and the depth of the concave hole is 2-4 mm.

Since pressure roller 23 is an elastomeric material as the web passes through the nip, pressure roller 23 is partially pressed into the pre-load hole as it passes through the nip, interacting with cooling roller 24 in the region of the pre-load hole to laminate aluminum foil layer 14 with inner adhesive layer 15 and innermost layer 16. The recesses are also slightly deformed in the press nip to relieve the stress in the aluminium foil at the circumference of each recess and allow the aluminium foil layer 14 to fully bond with the inner adhesive layer 15, the innermost layer 16. And each concave hole can absorb a small amount of air, so that air included between layers can be extruded.

Example 3

Lamination of the composite outermost layer 11 on the paperboard core layer 12 is performed at a compounding position comprising a pressure roll 25 and a cooling roll 26. The compounding position comprising pressure roll 25 and cooling roll 26 may be performed before the compounding position comprising pressure roll 21 and cooling roll 22, i.e. laminating the composite outermost layer 11 on the paperboard core layer 12 before laminating the composite core adhesive layer 13 and the aluminium foil layer 14 on the paperboard core layer 12; the laminating position comprising pressure roll 25 and cooling roll 26 may also be performed after the laminating position comprising pressure roll 23 and cooling roll 24, i.e. laminating the composite outermost layer 11 on the paperboard core layer 12 after laminating the composite inner adhesive layer 15 and innermost layer 16 on the aluminium foil layer 14; the laminating position comprising pressure roll 25 and cooling roll 26 may also be performed between the laminating position comprising pressure roll 21 and cooling roll 22 and the laminating position comprising pressure roll 23 and cooling roll 24, i.e. laminating the composite outermost layer 11 on the paperboard core layer 12 between laminating the composite core adhesive layer 13 with the aluminium foil layer 14 on the paperboard core layer 12 and laminating the composite inner adhesive layer 15 with the innermost layer 16 on the aluminium foil layer 14. The paperboard core layer 12 or the composite layer comprising the paperboard core layer 12 is brought into contact with a pressure roll 25 and the molten curtain of the outermost layer 11 is first poured onto a cooling roll 26 and then laminated together with the paperboard core layer 12 in a press nip between the pressure roll 25 and the cooling roll 26.

As shown in fig. 6, on the circumference of the pressure roller 25 corresponding to the position of the pre-press hole, a plurality of rows of grooves are provided. In order to ensure uniformity, the positions of the grooves in each row in the axial direction of the pressure roller 25 are uniform, and the grooves in each row are arranged at equal intervals, the distance between two adjacent rows of grooves is the same, but the positions of the grooves in each row in the circumferential direction are staggered. Of course, the grooves may not be arranged in rows, but may be distributed in any discrete manner, as long as a uniform distribution in the area of the pre-pressing holes is ensured. The width, depth, length and spacing of the grooves can be flexibly set according to the diameter and hardness of the pressure roller 25 and the size of the prepressing hole, and preferably the width, depth and length of the grooves are 1-3 mm, 2-4 mm and 15-25 mm.

Since the pressure roll 25 is of an elastic material when the web passes through the press nip, the pressure roll 25 is partly pressed into the pre-pressing holes when the pre-pressing holes pass through the press nip, and interacts with the cooling roll 26 in the area of the pre-pressing holes for laminating the core layer 12 of the cardboard with the outermost layer 11. If a pressure roller 25 and a cooling roller 26 are provided after the pressure roller 23 and the cooling roller 24, a composite layer of the paperboard core layer 12, the core adhesive layer 13, the aluminum foil layer 14, the inner adhesive layer 15, the innermost layer 16 is laminated with the outermost layer 11. If a pressure roller 25 and a cooling roller 26 are provided between the pressure roller 21 and the cooling roller 22 and the pressure roller 23 and the cooling roller 24, the composite layer of the paperboard core layer 12, the core adhesive layer 13, the aluminum foil layer 14 is laminated with the outermost layer 11. The grooves are slightly deformed in the press nip so as to relieve the stress in the aluminum foil in a direction perpendicular to each groove, so that the laminated layers are sufficiently bonded. And the groove rows are arranged such that at least one groove extends in the direction of rotation of the pressure roller 25 out of the pre-pressure hole, whereby air trapped between the layers can be squeezed out.

It will be clear to those skilled in the art that the above-described shape structures of the pressure rollers 21, 23, 25 are all exemplified, and therefore, are all replaceable with each other in an actual production line. For example, the pressure roller 21 for laminating the composite core adhesive layer 13 and the aluminum foil layer 14 on the paperboard core layer 12 may be configured as the above-described pressure roller 23 or 25, the pressure roller 23 for laminating the composite inner adhesive layer 15 and the innermost layer 16 on the aluminum foil layer 14 may be configured as the above-described pressure roller 21 or 25, and the pressure roller 25 for laminating the composite outermost layer 11 on the paperboard core layer 12 may be configured as the above-described pressure roller 21 or 23.

The shape of the grooves on the pressure roller is not limited to the above-mentioned strip or circle, but may be an irregular pattern such as an oval, square, triangle, wave pattern, etc., or a combination thereof. The molten curtain extruded from the laminator is introduced into a press nip while being cooled, the grooves of the pressure roller are brought into contact with the outermost layer 11 or the core adhesive layer 13 or the aluminum foil layer 14 or the innermost layer 16 in different processes, and the layers introduced into the press nip are pressed while forming a plurality of ridges corresponding to the shapes of the grooves on the circumferential surface of the pressure roller on the layer directly or indirectly in contact with the pressure roller, and air passages for discharging air are formed in the ridges. The pattern of grooves may be various shapes such as straight lines and curved lines depending on the shape of the air passage intended. When using grooves on a pressure roll, the resulting adhesive properties when the composite layers are cooled and laminated are improved, especially for thin single layer thicknesses.

The grooves on the pressure roll may be cut, drilled, laser etched, ablated, laser drilled, plunge cut, machined, molded, or otherwise formed. The grooves do not have to be constant in cross section across the diameter of the pressure roll and may include spiral, chamfered, pyramidal, conical, and the like structures. The plurality of grooves, distributed uniformly or non-uniformly, may be more easily deformed than the elastic material of the pressure roller to adapt to the pressure exerted on the pressure roller.

Although the grooves on the pressure roller have a very good effect on the adhesion properties of the region of the pre-pressed holes, the grooves are not arranged with a total area that is too large to avoid negative effects on the interlaminar adhesion in the region between two adjacent pre-pressed holes on the sub-web, so that it is preferred to design the grooves in as large a number as possible, but with a total area that is as small as possible.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (14)

1. Pressure roller for manufacturing laminated packaging material, arranged on a composite production line of laminated packaging material, said pressure roller being arranged in pairs with cooling rollers also arranged on said production line, a semi-finished packaging material pre-provided with pre-press holes passing through a squeezing nip between said pressure roller and a set of rollers consisting of said cooling rollers, the outermost layer of said pressure roller being of a polymeric elastic material, characterized in that on each circumferential zone of the outermost layer of said pressure roller corresponding to the position of said pre-press holes a plurality of discontinuous grooves is provided.

2. The pressure roll of claim 1, wherein the grooves are a left and right series of grooves, each groove in the left series of grooves being angled to the left at an angle to the direction of the pinch nip and each groove in the right series of grooves being angled to the right at the same angle to the direction of the pinch nip.

3. The pressure roller as claimed in claim 2, wherein each groove crosses a circumference at a center of a circle of the pre-pressing hole, an inner end of each groove is close to the circumference at the center of the circle of the pre-pressing hole, an outer end of each groove crosses a maximum edge of the pre-pressing hole in an axial direction of the pressure roller, and an outer end is close to the maximum edge of the pre-pressing hole in the axial direction of the pressure roller, the inner end being forward of the outer end in a rotational direction of the pressure roller.

4. The pressure roller as recited in claim 2, wherein the left and right oblique included angles range from 30 ° to 60 °.

5. A pressure roller as claimed in claim 1, characterized in that said grooves are discrete but evenly distributed grooves.

6. A pressure roller as claimed in claim 1, characterized in that the grooves are a plurality of rows of interrupted groove sequences arranged equidistantly, the groove discontinuities in two adjacent rows of groove sequences being non-aligned.

7. A pressure roller according to any of claims 1 to 6, characterized in that the groove shape comprises, but is not limited to, a strip, a circle, an irregular pattern, an oval, a square, a triangle, a wave pattern.

8. Method for manufacturing laminated packaging material, characterized in that a pressure roll according to any of claims 1-7 is arranged in at least one compounding position of a compounding line of laminated packaging material, said pressure roll being arranged in pairs with a cooling roll in said compounding position, and a semi-finished packaging material, which is pre-provided with pre-press holes, is passed through a press nip between said pressure roll and a set of rolls consisting of said cooling roll.

9. The method of claim 8 including step one wherein laminating the composite core adhesive layer and the aluminum foil layer on the paperboard core layer is performed at a first compounding location.

10. The method of claim 9 including a second step after the first step wherein laminating the composite inner adhesive layer with the innermost layer on the aluminum foil layer is performed at a second composite location.

11. The method of claim 10 comprising a third step before or between the first and second steps or after the second step, wherein laminating the composite outermost layer on the paperboard core layer is performed at a third composite location.

12. A composite packaging material manufactured using a pressure roll according to any one of claims 1-7 or using a method according to any one of claims 8-11 for forming a packaging container.

13. A packaging sheet made of the composite packaging material according to claim 12, each for forming an individual packaging container.

14. A packaging container formed from the composite packaging material according to claim 12 or the packaging sheet according to claim 13.