DE2423209A1 - Corrugated cardboard with fabric reinforcement - pref. glued to plastics sheet at one or both faces - Google Patents

Abstract

A plate or sheet-like material comprises a reinforcing fabric constituted of rows of crossed cords applied onto one, pref. both faces of the plate material. The material is pref. a cardboard type material with one set of parallel rows of reinforcing cords and a second set, also mutually parallel and generally perpendicular to the first. The rows may be applied directly onto one or both surfaces or, alternatively, may be first applied onto a plastics substrate, which is itself then applied to one or both faces of the cardboard. Pref. two liners have a conventional corrugated cardboard layer sandwiched between them.

Description

Cardboard / plastic material reinforced with a net-like fabric The invention generally refers to certain novel and useful improvements in the case of corrugated cardboard / plastic materials and in particular a corrugated cardboard material that Reinforced by a net-like fabric in the form of rows of crossed strands is.

Corrugated board materials have widespread use on many found commercial and industrial applications, for example at the manufacture of shipping boxes, storage containers and other container shapes that can be used in a variety of ways. In addition, corrugated cardboard materials in recent times for some structural applications use, primarily Line in many areas where previously stiffer materials, such as plastic or sheet metal.

Manufacturers of such materials have found that it to expand the areas of application for corrugated cardboard materials necessary is to reinforce these materials in order to use them in this way for these other areas of application to make suitable. The techniques currently used to reinforce corrugated board materials are generally on the use of additional or thicker layers built up during the manufacture of the cardboard material. However, these techniques have proven themselves not proven overly effective and have the total cost to manufacture of the cardboard material increased significantly.

The present invention addresses those mentioned above as well as others. Disadvantages avoided by adding a reinforcing mesh-like fabric to one or more Surfaces of the cardboard material is applied. The net-like fabric is designed in such a way that that optimal reinforcement can be achieved without the currently usual manufacturing processes to change significantly for the corrugated cardboard. In addition, the aesthetic Appearance of the cardboard material improved.

The present invention is concerned with a novel product in the form of an improved corrugated board material and with a novel process for reinforcing corrugated cardboard material. The improved paperboard material includes a reinforcement a net-like fabric which is applied to at least one of its surfaces and comprises rows of crossed or overlapping strands / ribbons.

In one embodiment, the rows of crossed strands are which form the reinforcing net-like fabric, characterized in that one A plurality of first substantially parallel and spaced apart from one another Rows of strands and a plurality of second substantially parallel and rows of strands arranged at a distance from one another form a matrix in the form of a forming reinforcing reticulated fabric, the second rows of strands essentially run perpendicular to the first rows of strands.

These reinforcing strands may or may not be woven.

In one embodiment of the present invention, the reinforcing Fabric can be applied directly to a surface of the corrugated board material. At a Another embodiment can be the reinforcing strands or the net-like fabric be applied to a surface of a Xoplaststoffsubstrates, which then on at least an exposed flat surface of the paperboard is applied. With another Another embodiment of the present invention are these rows of the crossed Strands on both opposing exposed flat surfaces of the paperboard material upset. In a similar way, the rows of strands can be applied to a surface of the plastic substrate be applied, this substrate being exposed on both opposing sides Flat surfaces of the corrugated cardboard material is applied. In yet another embodiment of the present invention can use the crossed Rows of strands on both flat surfaces of the plastic substrates be applied, after which these substrates Usually applied to both exposed surfaces of the paperboard material are the crossed rows of strands that form the reinforcing net-like fabric, glued to the surface of the cardboard material. In another embodiment the strands can be pre-formed in connection with a plastic substrate, and this plastic substrate can be glued to the surface of the cardboard material or otherwise by any of the known methods of joining Plastic films are attached with cardboard materials.

In general, the preferred method of making the reinforced corrugated cardboard material in that at least one of the paper or cardboard layers (which are usually the structural elements of a conventional corrugated board material form) before the production of the corrugated cardboard material itself with the net-like fabric is coated. The application of the net-like fabric on a flat layer, without the corrugated layer being present is usually simpler than that Applied to a cardboard material containing a corrugated layer. Such a thing specially reinforced laminate and a method of making the same is disclosed in Canadian Patent 879,070. If once a reinforced cardboard layer is formed, it will at least be as one of the structural elements used in a product made from corrugated cardboard material. For example, such reinforced layer can be used for the edging and / or corrugated layers. In most cases it is usually sufficient to have them as one of the edging layers is used. In general, such products can be made using conventional Equipment or manufactured from such equipment with little modification will. A more recent method of making a corrugated product is in US Pat Canadian Patent 879,643. This product and that described in it Methods can be of interest to the present invention.

As described above, the corrugated paperboard material usually comprises one Pair of spaced apart liners and one between the corrugated layer (generally as a double-face bordered on both sides - Corrugated cardboard). In this case the reinforcing mesh is on attached to the outer surface of one of the edging layers. If only one edging layer is used (generally referred to as single-face corrugated cardboard), the reticulated fabric is attached to the outer surface of that one edging layer.

In other products, the fabric can be attached to the inner surface of the edging layer or attached to the edging layers be. Another embodiment of the paperboard material according to the invention comprises at least two outer facing layers and an inner surround layer, each between the inner surround layer and a corrugated layer is disposed on an outer framing layer. At this Embodiment, the net-like fabric in various ways, as suggested above, be attached; generally one will either do it on the outer surface of one outer framing layer or of both outer framing layers or between attach the edging layers. It is expressly noted that the above The two embodiments described are only exemplary for a large number of cardboard materials that can be reinforced according to the present invention. It is also possible for the product to have several layers of corrugated material includes.

In many cases the reinforcing reticulated fabric and / or the plastic substrate and / or the cardboard elements a suitable flame retardant Agents, for example any of the known organic phosphorus compounds, added, or the reticulated fabric and / or the plastic itself can be fireproof be.

In addition, the cardboard material is improved by the fact that the reinforcing reticulated tissue its aesthetic he appearance shape improved. The reinforcing fabric is made from a network of crossed rows of strands formed with the strands or rows generally perpendicular to one another are. The reinforcing fabric and / or the plastic substrate with which it is molded can be appropriately impregnated with a coloring agent or the like so that the cardboard material is given a colored external appearance, or it can be provided with a suitable pattern. This way it will be in both Felling achieved through the fabric not only a reinforcement of the cardboard material, but the attractiveness of the material is also increased and the product becomes different imparted desirable properties.

In the illustration the reinforcing reticulated fabric includes this crossed rows of strands that are arranged at right angles to each other. In addition, however, other geometric shapes can also be used. For most uses will be due to the increased reinforcing effect and the arrangement of the crossed rows at a right angle for ease of manufacture preferred to each other. For many purposes, however, the use of Strands that cross at an acute angle should be appropriate.

The plastic material that is used when that reinforcing reticulated fabric, as described above, formed on a plastic substrate or is covered by a plastic film, can be made of known materials, for example Polyethylene, P, olypropylene and some copolymers thereof and some polyester and polyvinyl (PVC) materials etc.

These plastic films or substrates can be biaxial be oriented. However, such an orientation cannot exist either. For cost reasons and because it is easily adherent, polyethylene is low density the preferred plastic material. The strand material can consist of individual linear Filaments can be shaped to reinforce the surface to which they are applied. For example, each strand can be made up of a plurality of aligned fibers or Filaments that can be of natural origin such as jute, sisal, asbestos, cotton, or made of synthetic materials. The preferred Strand materials are in the form of strips or ribbons. In particular, be the materials described in Canadian Patent 879,070 are preferred. These strips or tapes should not be less than 0.5 mil (0.0127 millimeters) thick. otherwise the resulting laminate will not have an adequate increase in tensile strength, especially the puncture resistance and tear resistance, compared to materials which does not involve the use of film strips. It was found out that when a thickness of 0.0762 mm (3 mil) is exceeded, the increase in strength achieved not the extra effort associated with using the thicker film justifies.

The width of the strip or tape should not be less than 2.54 mm (0.1 ') and not larger than 5.08 mm (0.2').

This bandwidth is used in conjunction with a special lateral Distance between the bands that is not less than 1.27 mm (0.05 ") and not should be greater than 7.62 mm (0.3 "), the BXd product with the required tear strength created.

The maximum elongation of the bands or strips should not be 30 ff and should preferably exceed that of paper in most cases correspond. The ligaments should therefore be oriented so that their maximum extension is in the range of 5 - 30 ß, otherwise the paper or cellulose material to early before the ribbons would tear.

The following detailed information serves to better explain the invention Description in conjunction with the accompanying drawings, in which individual practical Embodiments of the invention are shown.

Fig. 1 is a vertical section showing the interior of the improved paperboard material shows that has been made in accordance with the invention; Fig. 1a is a plan view to the improved paperboard material of Fig. 1 with parts broken away to show individual To show interlayers; Fig. 2 is a vertical section through another embodiment of the improved paperboard material of the invention; Fig. 2a Fig. 2 is a top plan view of the paperboard of Fig. 2 with parts broken away; to show individual intermediate layers; Fig. 3 is a vertical section of another Embodiment of the improved cardboard material of the invention; Figure 3a is a top view on the cardboard material shown in Fig. 3, with parts broken away to individual To show interlayers; Fig. 4 is a fragmentary perspective view, in part in section and with parts broken away showing the application of the reinforcing material shows reticulated fabric on a plastic substrate, which in the improved invention Cardboard material is used; and Fig. 5 is a vertical section through still another embodiment of the Pappma terials according to the invention.

If one now turns to the drawings in detail, one recognizes in Fig. 1 an improved cardboard material denoted by A, the generally a pair of spaced opposed ones Comprises outer layers 10 and 12 or so-called lining layers (liners), separated by a corrugated or grooved layer 14 and connected to this are. A reinforcing net-like fabric 16, the crossed rows of strands, as in FIG Figs. 1 and 1a, is comprised of the upper and outward-facing flat surface of the edging layer 10 is applied. This matrix-like, reticulated Tissue can be adhered to the surface of layer 10 or can be in any be upset in another way. Known adhesives can be used for this purpose Find.

As previously indicated, in one embodiment of the method the edging layer 10 is coated with the fabric 16 using conventional techniques Find application, and reinforced by the fabric 16 edging material 10 and the edging layer 12 are then attached to the corrugated layer 14 in a separate Operation attached, using conventional techniques for the manufacture of corrugated cardboard Find application. A preferred method of securing the reticulated tissue 16 on the edging layer 10 is that the surface of the edging layer 10 coated with a low density polyethylene film by using an extruder and that, while the film is still relatively fluid, the net-like fabric 16 into the polyethylene film embedded / inserted, the Polyethylene film after cooling is not used to attach the fabric 16 on the Edging layer 10 is used, but also for further reinforcement and as a barrier for liquids, gases, punctures, etc.

The thickness of the polyethylene film used depends on the desired Properties from; however, in many cases, a film with a thickness of about 0.0127 mm (0.5 mil) found effective. The facing layers usually exist made of kraft cardboard with a basis weight of about 42 lbs. per 1,000 square feet that Corrugated layer is usually made of kraft cardboard or a semi-chemical Medium with a basis weight of 26 lbs. per 1,000 square feet. The net-like fabric can be made from a variety of materials. A preferred type of material is described in Canadian Patent 879,070 and consists, for example Made from a loosely woven fabric made of polypropylene tapes that have a molecular orientation and are approximately 2.54 mm (0.10 t ') wide and 0.0254-0.0508 mm (1-2 mils) thick and which are substantially perpendicular to each other, with between the bands there is a gap of 6.35-3.17 mm (1 / 4-1 / 8 H).

It has been found that this embodiment is suitable for general purposes proves effective.

There is t the possibility of a modified form of an improved one To create cardboard material. This embodiment B essentially corresponds to that shown in Figures 2 and 2a.

The reinforced paperboard material B here also includes a pair of in the Spaced, substantially parallel outer frame layers 18 and 20, separated by and connected to a corrugated intermediate layer 22 are. A plastic mat or substrate 24 on which the reinforcing reticulated Fabric 26 is applied is in a suitable manner, for example by gluing or other known means applied to the surface of the surround layer 18.

In this case, the plastic mat 24 is applied so that the reinforcing reticulated fabric 26 to the exposed surface of the symbiotic layer 18 is attached. The plastic mat 24 can, however, also be applied so that the reinforcing fabric 26 is exposed.

The last-described product and a process for its manufacture the same and a method of attaching the fabric to the edging layer has already been described in connection with FIGS. 1 and 1a. For the above Product in which the fabric 26 is overlaid by a plastic mat / film 24, meets the general and detailed description of the manufacture of the product A too. For example, such a product was made by a Polyethylene film was extruded onto the skirt layer 18 and, while the Polyethylene layer was still relatively liquid, the net-like fabric 26 and the plastic mat / film 24 were placed on the polyethylene adhesive layer in this order.

This reinforced edging layer 18, 26, 24 was put together with of the edging layer 20 is attached to the corrugated layer 22, conventional Techniques for the production of corrugated cardboard material found application.

This form of the plastic mat 24 is shown more completely in FIG. In this connection it should be noted that a similar reinforcing fabric can be applied to the lower surface of the plastic mat 24.

The different strands are usually on the plastic mat 24 glued. However, they can also be molded in or in one piece in some other way be formed with the mat 24.

3 and 3a is yet another embodiment of the invention Corrugated cardboard material shown. The paperboard material C generally comprises a pair of spaced apart parallel outer enclosure layers 28 and 30, between which an intermediate enclosure layer 32 is arranged. Between the outer facing layer 28 and intermediate facing layer 32 is a corrugated Layer 34 arranged and connected to these layers. As can be seen in Fig. 3 can see, extends / further a second corrugated layer 36 between the outer edging layer 30 and the intermediate edging layer 32, these second corrugated layer 36 with the opposite face of the intermediate edging layer 32 and the edging layer 30 is connected. In this embodiment is on the exposed one Surface of the upper cladding layer 28 a reinforcing net-like fabric 38 attached to a plastic mat 40.

The mat containing the fabric is the same as that shown in FIG and is described in connection therewith. Of course, a similar reinforcing fabric can be used also be attached to the exposed surface of the outer cladding layer 30, or it can suitably be a plastic mat / film and one on top Reinforcement fabric applied to the exposed surface of this Linfassachicht will.

Similarly, any or all of the enclosure layers may be used 28, 30, 32 and corrugated layers 34, 36 with a reinforcing reticulated fabric be provided that is attached to one of its surfaces. Details about it were made already mentioned above. Corrugated board material with two corrugated layers is used in the Trade referred to as double wall board (the one with a Layer as a single wall board. To the different with tissue To put reinforced edging / corrugated layers together, conventional Techniques for making such corrugated cardboard materials are used.

In Fig. 5 is a further modified embodiment of the invention Cardboard material shown. The material D comprises a pair of outer jacket layers 42 and 44 and a corrugated intermediate layer 46 applied to the inner surface of the Edging layer 44 is applied. A plastic mat 50 upon which the reinforcing fabric 48 is applied, which essentially corresponds to the mat provided with the fabric 26, is applied to the inner surface before the complete assembly of the cardboard material the frame layer 42 is applied. The tissue is located with the inner one Surface of the enclosure layer 42 in engagement and is firmly connected to this, after which the plastic mat 50 is connected to the elevations of the corrugated material 46 will.

In this connection it should be noted that a similar reinforcing net-like fabric or a plastic mat with a reinforcing fabric on it may be inserted between the edging layer 44 and the corrugated layer 46 can. If further reinforcement is required, the reinforcement fabric can also on one or both outer sides of the respective edging layers 42 and 44 are applied.

In a further embodiment, instead of directly to the corrugated layer 46 of plastic mat / film 48 bonded this to a third cardboard edging layer be tied, and this edging layer can be attached to the ridges of the corrugated Materials 46 will be addressed.

This embodiment is for conventional equipment in the Corrugated cardboard manufacture is more suitable, while that shown in Fig. 5 is easier the method and apparatus described in Canadian Patent 879,643 can be produced. An exemplary product is described below, which uses three edging layers: An edging layer Kraft cardboard (42 lbs. per 1000 square feet). with a 0.0127 mm (0.5 mil) thick polyethylene film coated; a 0.0127 mm (0.5 mil) thick polyethylene film was extruded onto kraft cardboard (40 lbs. per 3000 square feet), and while the polyethylene was still relatively fluid, became a reinforcing mesh-like fabric and that before 42 lbs. of coated cardboard placed on top of the polyethylene layer in that order (with the polyethylene side the 42 lbs. cardboard on the reinforcing fabric). This reinforced double edging layer, along with another 42 lbs. rraft cardboard facing layer adhered to a corrugated kraft media, wherein the uncoated surface of the 42 lbs. layer (the double edging layer) to the bumps of the corrugated layer using conventional equipment was tied up.

From the description of these special forms of execution one can see that in accordance with the invention produced a large number of improved paperboard materials can be, and that the present invention is not limited to those described herein and illustrated embodiments is limited.

As is clear from the foregoing, one of the goals is the Invention to reinforce products currently on the market to expand their field of application. Because of the special nature of the material from which If they are manufactured, products made of non-reinforced cardboard open up a wide field for improvements. This statement applies in particular to products made from corrugated cardboard to. In addition, such improvements can also be made on inexpensive materials made of relatively weak plastic. Foamed materials Plastics are a good example of this, for example, foamed polystyrene, Urethane, etc. Such materials can be used in a simple manner reinforced are by placing the aforementioned net-like reinforcing fabric on an or both surfaces of the materials using the methods described above is applied. For example, a 0.0254 mm (1 mil) thick polyethylene film was used onto the surface of a 12.70 mm (one-half inch) sheet of foamed foam Polystyrene was extruded and, while the polyethylene was still relatively liquid, was a mesh reinforcement fabric and a 42 lb. kraft cardboard edging layer (previously coated on one side with a 0.0127 mm (0.5 mil) thick polyethylene layer) in this order on the polyethylene layer (with the polyethylene side of the 42 lbs. edging layer placed on the reinforcement fabric). The polyethylene reinforcement fabric-polyAthylene cardboard layer leads to an increase in strength of the foamed polystyrene length.

The product according to the invention reveals its greatly increased strength properties compared to similar conventional products in particular with regard to its Puncture (puncture) strength, tear strength and burst strength.

This increase in strength comes with a lower cost per unit Increased strength than associated with conventional methods. When the polyethylene film solution is used to attach the fabric with the edging layer or medium connect, the product is also impermeable to moisture and water. In addition, the reinforcement increases the resistance to bulging and increased fatigue.

The following table shows products according to the invention (£ P) compared with conventional products (HP), which do not have a net-like fabric.

Material type Impact / burst strength- ability HP EP HP EP HP EP single-walled (200C) 210 890 230 440 - much more (275C) 300 965 380 575 355 600 n (350C) 315 950 380 510 415 double-walled (275BC) 375 1065 360 465 - (350BC) 410 1050 410 565 340 (500BC) 515 1155 - - 490 (600BC) 555 1155 - -Three-walled 1100 - - -Note - Tests at 50% relative humidity.

From the table above it is evident that the invention Products with certain strength properties match those of conventional products. are superior. In addition, it can be seen from the table that the penetration / Puncture resistance value of the fabric-reinforced double-walled product with that of one conventional three-walled product is comparable, but the cost of the the first-mentioned product are much lower than those of the last-mentioned product.

In addition, a fabric-reinforced double-walled cardboard product also significantly higher puncture / puncture strength than 6.35mm (1/4 inch) tempered masonite board. This was after adapted to the free-falling dart method found ASTM test D1709.

The arrow weighed 3 pounds. and was taken from a height of 0.9144 m (3 feet) dropped onto the center of a curved sample.

The width of the sample was 45.72 cm (18 inches with an arch height 45.72 cm (18 in).

Sample Number of Versu- Number of attempts leading to punctures leading to Through led blows led 11 / 4fii tempered material 14 21 350 double-walled Material 48 52 When the reinforced fabric 'of the present invention is shown in When end products are transferred, these products also have better properties on. For example, it occurred in a buffing test of a 50 lb. nail box (packed with nails) made of a fabric-reinforced single-walled cardboard (2.75B type) was manufactured 190 times on failure, while one from a conventional one Cardboard (275B) and nail cardboard made of 275B sleeve failed 140 times.

It has been found that the fabric-reinforced material is the present invention in an excellent way for many other end products, such as storage containers, plate elements, water / moisture-proof containers, etc. suitable.

Claims (17)

Patent claims: 1. Plate material, characterized by a net-like reinforcing fabric of rows of crossed strands applied to at least one surface of the sheet material is upset. 2. Cardboard material according to claim 1, characterized in that the rows dr crossed strands a plurality of first spaced apart essentially parallel rows of strands and a plurality of second spaced apart mutually arranged essentially -parallel rows of strands, which are essentially are arranged perpendicular to the first rows of strands, include. 3. Cardboard material according to claim 2, characterized in that the rows of strands are applied directly to a surface of the paperboard material. 4. Cardboard material according to claim 2, characterized in that the rows of strands are applied to a surface of a plastic substrate that at least an exposed flat surface of the paperboard is applied. 5. Cardboard material according to claim 2, characterized in that the rows of strands applied to both of the opposing exposed flat surfaces of the paperboard material are. 6. Cardboard material according to claim 2, characterized in that the rows of strands are applied to a surface of a plastic substrate and that such Plastic substrate on both opposing exposed flat surfaces of the Cardboard material is applied. 7. cardboard material according to claim 2, characterized in that the rows of strands are applied to both flat surfaces of a plastic substrate and that the substrate on at least one exposed flat surface of the paperboard material is upset. 8. Cardboard material according to one of claims 3 to 7, characterized in that that the strands are glued to the plastic substrate or the cardboard material. 9. cardboard material according to claim 2, characterized in that there is a Pair of spaced apart edging layers and one between comprises these arranged corrugated element and that the net-like reinforcing fabric is applied to the outer surface of one of these edging layers. 10. Cardboard material according to claim 2, characterized in that it is at least two outer skirting layers and one inner skirting layer and between the outer surround layers and the inner surround layer includes corrugated elements and that the reticulate Reinforcement fabric applied to the outer surface of one of the two outer facing layers is. 11. A method for reinforcing cardboard material, characterized by the application of a net-like reinforcing fabric, the rows of crossed Strands onto a flat outer surface of the paperboard material. 12. Yerfahren according to claim 11, characterized in that the rows of the crossed strands a plurality of first spaced apart strands essentially parallel rows of strands and a plurality of second spaced apart to one another arranged essentially parallel rows of strands, which are essentially are arranged perpendicular to the first rows of strands, include. 13. The method according to claim 12, characterized in that the strand rows can be applied directly to a surface of the paperboard material. 14. The method according to claim 12, characterized in that the rows of strands be applied to a surface of a plastic substrate and that the substrate then applied to at least one exposed flat surface of the paperboard material will. 15. The method according to claim 12, characterized in that the rows of strands applied to both of the opposing exposed flat surfaces of the paperboard material will. 16. The method according to claim 12, characterized in that the rows of strands be applied to a surface of a plastic substrate and that such Then place plastic substrate on both of the opposing exposed flat surfaces of the cardboard material is applied. 17. The method according to claim 12, characterized in that the rows of strands are applied to both flat surfaces of a plastic substrate and that this substrate on at least one exposed flat surface of the paperboard material is applied. Blank page