Use of at least one ply cellulose wadding for the production of reshaped products

Abstract

To solve the problem of providing a recyclable and climate-friendly material for the production of formed products, the use of at least a single layer of cellulose wadding comprising cellulose in the form of a web or in the form of blanks for the production of formed products is proposed.

Description

[0001] The present invention relates to the use of at least one layer of cellulose wadding for the production of formed products.

[0002] Pulp is obtained by pulping plant fibers and consists primarily of cellulose. A wide variety of products are manufactured from pulp, such as paper, tissue products, diapers, etc. Pulp is available in various grades. For many applications, bleached or unbleached pulp, or raw material derived from recycled paper, is used. From this, pulp wadding can be produced. After dissolving the pulp or raw material from recycled paper in water in a pulper, a mechanical treatment is carried out, followed by dewatering to obtain the product, which is then dried. Subsequently, further mechanical treatment takes place in the paper machine, where pulp wadding is produced, particularly with a high degree of creping.

[0003] Cellulose wadding is a special type of material made from softwoods, and sometimes also hardwoods. It has excellent water-binding properties and is therefore primarily used for hygiene products such as sanitary napkins, incontinence products, and similar items.

[0004] Formed products according to the present invention are used in particular as packaging. These can be in the form of trays or bowls, for example, to hold sausage, cheese, or fruit, or in the form of blisters or similar containers. These are usually made of plastic or plastic substitutes and generally have chemical additives and, in particular, surface sealants to prevent the packaging from becoming soggy, especially in the case of plastic substitutes. Packaging products made of plastics, but also of coated plastic substitutes, are difficult to recycle, especially when they are multi-layered, regardless of the material, and are therefore generally thermally recycled, for example, by incineration.It would therefore be desirable to provide packaging products that could not only be thermally recycled but, in particular, also be effectively recycled. Furthermore, it is desirable to manufacture packaging products from materials that have a low carbon footprint and are, for example, made from renewable resources.

[0005] It is therefore an object of the present invention to provide formed products, which can be used in particular as packaging, which are recyclable and at the same time less harmful to the climate, in particular climate-neutral, compared to existing products of the generic type.

[0006] This problem is solved according to the invention by using at least a single layer of cellulose wadding comprising cellulose in the form of a web or in the form of blanks for the production of formed products. For the purposes of the present invention, the term "formed products" is understood to mean, for example, that a web or blank of cellulose wadding is hot- or cold-formed under pressure. Optionally, a vacuum can also be used. The single layer of cellulose wadding as a raw material is thereby formed into a semi-finished product or a finished product, for example, a packaging container. Typical processing temperatures can be in a range between about 10°C and about 450°C, preferably about 50°C and about 400°C, and even more preferably from about 175°C to about 375°C.In addition to applying pressure, tension can also be exerted on the web or blank of cellulose wadding during the production of formed products, so that in this sense one can also speak of tensile-compressive forming, here referring to cellulose wadding. However, pure pressure forming, for example by rolling or die forming, is also possible with a web or blank of cellulose wadding according to the present invention, in order to use it for the production of formed products. The cellulose wadding used is preferably made of softwood, in particular coniferous wood. Preferably, the at least single-layer cellulose wadding comprises long-fiber cellulose. More preferably, the cellulose used to produce the cellulose wadding has a fiber length in the range of about 1 mm to about 5.5 mm, more preferably in the range of about 2 mm to about 5 mm, and even more preferably in the range of about 2.5 mm to about 4.5 mm.The fiber length of the cellulose used is preferably retained in the cellulose wadding.

[0007] The cellulose wadding of the present invention, used for the production of formed products, in the form of a single layer, has a crepe factor in the range of approximately 15% to approximately 80%, more preferably in the range of approximately 35% to approximately 75%, and a basis weight in the range of approximately 16 g / m² to approximately 50 g / m². The aforementioned crepe factor is very high and distinguishes the cellulose wadding from other products derived from pulp. It is preferably produced from bleached and unbleached pulp or from recycled paper, more preferably from unbleached pulp or from recycled paper. Mixtures of bleached pulp and / or unbleached pulp and / or raw material from recycled paper can also be provided, depending on the requirements placed on the formed products.

[0008] When the terms "approximately" or "essentially" are used in connection with values ​​or ranges of values, or with properties or geometries, within the scope of the present invention, they are to be understood as a tolerance range that a person skilled in the art considers customary in this field. In particular, when using the term "approximately," a tolerance range of + / - 20%, preferably + / - 10%, and more preferably + / - 5% is provided in connection with values ​​or ranges of values. Lower limits of value ranges may be undercut by 5% to 20%. Upper limits of value ranges may be exceeded by 5% to 20%. Where different value ranges, for example, preferred and more preferred value ranges, are specified in the present invention, the lower limits and the upper limits of the different value ranges can be combined with one another.

[0009] Preferably, the formed products manufactured using at least one layer of cellulose wadding are packaging materials. These can be designed in particular as trays, blisters, bags, containers, etc. The packaging materials are preferably suitable for packaging foodstuffs. However, other products can also be packaged with them, for example, pharmaceutical products, cosmetics, medical devices, technical equipment, and drugstore items, the aforementioned products being examples only.

[0010] The particular advantage of the invention's use of at least one layer of cellulose wadding for the production of formed products lies in the fact that it makes possible to produce formed products made exclusively from renewable raw materials and leaving virtually no CO2 footprint. Above all, these products can also be recycled, as they do not require the coatings otherwise necessary for food products. They can therefore be collected separately with other paper waste and processed accordingly, in particular recycled.

[0011] The at least single-layer cellulose wadding can contain other fibers besides cellulose, which are added during production. Particularly preferably, the at least single-layer cellulose wadding can contain a proportion of cotton fibers. Suitable cotton fibers advantageously have a fiber length in the range of approximately 1 mm to approximately 25 mm. However, fibers from hemp, bamboo, or other renewable raw materials can also be used. The fiber length of the other fibers is preferably in the range of approximately 1 mm to approximately 25 mm, more preferably in the range of approximately 1.5 mm to approximately 10 mm, and even more preferably in the range of approximately 2 mm to approximately 8 mm. The proportion of other fibers, as mentioned above, in the at least single-layer cellulose wadding for the production of unshaped products is in the range of approximately 1 wt.% to approximately 50 wt.%, more preferably in the range of approximately 2 wt.% to approximately 40 wt.%.-%, and even more preferably in a range of about 10 wt.% to about 35 wt.%, based on the total amount of cellulose wadding.

[0012] The formed products manufactured using at least a single layer of cellulose wadding can also have a multi-layered structure. For example, one or more layers of an airlaid material (non-woven material, such as a nonwoven fabric) can be arranged on one or more layers of cellulose wadding, on each side of the airlaid layer. Conversely, one or more layers of cellulose wadding can be arranged between one or more layers of an airlaid material that is arranged on both sides of the cellulose wadding. Other types of multi-layered products can also be manufactured using at least a single layer of cellulose wadding. The invention allows cellulose, and thus cellulose wadding, to be used in a novel way.The use according to the invention of the at least single-layer cellulose wadding in forming processes for the production of semi-finished products or finished products from the raw material cellulose wadding, in particular in the context of pressure forming or tensile-compression forming, preferably tensile-compression forming at elevated temperatures, surprisingly makes it possible to produce high-quality products with excellent properties as packaging materials and to make them particularly usable in the food industry.

[0013] Deep drawing is a preferred tensile-compressive forming process, in which the at least single-layer cellulose wadding, in the form of a web or blanks, is fed to a suitable device and drawn under pressure into hollow forms. Advantageously, the products are manufactured by forming at the temperatures and under pressure specified above, for example, using a forming die with a specific pressure, such as in the range of approximately 10 bar to approximately 100 bar, relative to the part to be formed.

[0014] Advantageously, the at least one layer of cellulose wadding has a thickness according to DIN EN ISO 12625-3 (September 2014) in the range of approximately 0.12 mm to approximately 0.68 mm, more preferably in the range of approximately 0.15 mm to approximately 0.55 mm. These specifications refer to the at least one layer of cellulose wadding before the production of a formed product. Advantageously, cellulose wadding in the form of a web or in the form of blanks, generally multi-layered, in particular at least four-layered, for the production of formed products, which is fed into the forming process, has a thickness according to DIN EN ISO 12625-3 (September 2014) in a range of about 0.5 mm to about 70 mm, preferably in a range of about 1 mm to about 55 mm, more preferably in a range of about 1.5 mm to about 40 mm, and even more preferably in a range of about 1.6 mm to about 15 mm, before forming.Due to the creping of the at least single-layer cellulose wadding, the thickness of the usually multi-layered, in particular at least four-layered, cellulose wadding that is fed into the forming process cannot be used to determine the thickness of a single layer of the cellulose wadding.

[0015] In a preferred embodiment, cellulose wadding is used that is formed in at least four layers. The number of layers can consist of individual, stacked layers or be achieved by folding back a layer. For example, a four-layer cellulose wadding produced by doubling can be manufactured by folding back a single layer of cellulose wadding twice, or by stacking four individual layers of cellulose wadding on top of each other, which is preferred, or by folding back a single layer once and stacking two such double layers on top of each other. Advantageously, the cellulose wadding used for manufacturing formed products is formed in at least eight layers, more preferably in at least ten layers, and even more preferably in at least sixteen layers.A sixteen-layer cellulose wadding can be produced by layering eight double layers of cellulose wadding, each double layer being obtained by folding back a single layer. The basis weight of a layer of cellulose wadding is advantageously in the range of about 16 g / m² to about 50 g / m², more preferably in the range of about 20 g / m² to about 42 g / m².

[0016] The cellulose wadding used according to the invention advantageously has a crepe factor in the range of about 15% to about 80%, more preferably in the range of about 35% to about 75%, and even more preferably in the range of about 40% to about 70%. Creping is achieved by varying the drive speed of cylinders in a paper machine, in particular between the dryer cylinder and the winder (poperoller) on which the cellulose wadding used according to the invention is produced. For example, a crepe factor of about 50% is obtained if the winder runs about 50% slower than the dryer cylinder. The crepe factor is thus also a measure of the (breaking) elongation of the finished, at least single-layer cellulose wadding according to the present invention.The elongation is also influenced by other factors during production, such as the angle of the scraper blade in the paper machine when scraping the produced cellulose wadding from a drying cylinder. The crepe factor of the cellulose wadding used according to the invention is very high compared to the crepe factors of other materials made from pulp. In conjunction with other factors, especially the basis weight, it ensures a uniform appearance of formed products, particularly their surface, and, especially when using multi-layered cellulose wadding, results in very lightweight yet sufficiently strong formed products.

[0017] Preferably, the cellulose wadding used according to the invention has a moisture content in accordance with DIN 54540 Part 9 (2007-10) in the range of approximately 3% to approximately 40%, more preferably in the range of approximately 5% to approximately 35%, and even more preferably in the range of approximately 8% to approximately 32%, and even more preferably in the range of approximately 10.5% to approximately 29%. It may be provided that the cellulose wadding is additionally moistened after production in a paper machine to achieve higher moisture contents. Moisturizing can also take place subsequently in a forming machine or in a process upstream thereof.The moistening can be achieved, for example, by applying water or another liquid to the cellulose wadding before layering three single-layer sheets of cellulose wadding, preferably only to the inner layer. This can be done, for example, by spraying water on at least one side of the layer in question after the cellulose wadding has been produced and before layering or folding and rolling it up. This retains the moisture inside the three-layer cellulose wadding web. However, the outer layers of multi-layer cellulose wadding can also be moistened. Preferably, with regard to the use of the at least single-layer cellulose wadding according to the invention for the production of formed products, a moisture content is adjusted using water. Additionally, other substances can be added to impart specific features to the formed products.For example, grease- or oil-repellent agents can be applied to the at least single-layer cellulose wadding, preferably, in the case of a doubling of the at least single-layer cellulose wadding, to the inner surface of the cellulose wadding after doubling. Particularly preferably, the cellulose wadding used according to the invention is treated with at least one water- and / or oil-repellent agent. This agent is further preferably biodegradable and / or compostable, and particularly preferably comprises silicon dioxide compounds.

[0018] Advantageously, the at least single-layer cellulose wadding used for manufacturing formed products exhibits an elongation at break according to DIN EN ISO 12625-4 (March 2017) in the range of approximately 15% to approximately 180%, more preferably in the range of approximately 30% to approximately 120%, and even more preferably in the range of approximately 40% to approximately 95%. Preferably, the crepe factor in the latter, particularly preferred range, is approximately 45% to approximately 55%. Such values ​​for the elongation at break and the crepe factor are achieved particularly when only cellulose wadding is used in each layer. An elongation at break in the range of approximately 15% to approximately 40% is preferably associated with a crepe factor of approximately 15% to approximately 28%.Such values ​​for elongation at break and crepe factor are achieved particularly when at least one single-layer cellulose wadding forming outer layers is combined with at least one inner layer of an airlaid material. With an elongation at break in the aforementioned ranges, the production of products by forming process, especially packaging materials, particularly within the framework of a deep-drawing process using heat, is advantageously enabled.

[0019] In a preferred embodiment of the at least single-layer cellulose wadding used, in a multi-layer configuration, the moisture content of at least one inner layer is higher than the moisture content of an outer layer before forming the products. Preferably, in a multi-layer configuration, the outer layers of the cellulose wadding are not moistened after production, whereas inner layers can be moistened after production, particularly after leaving the paper machine, in order to achieve a desired moisture content for product forming.Preferably, as described above, during the folding or layering of at least one layer of cellulose wadding, at least one side of the wadding is moistened, and then this first layer is folded back, or a second layer of cellulose wadding is applied, which may also be moistened on at least one side, preferably on the side facing the first layer, so that the moisture content inside the then at least two-layer cellulose wadding is increased. The same procedure can be followed for multiple folding or layering of individual layers of cellulose wadding. Layers to be arranged in the middle can preferably be moistened on both sides.

[0020] As mentioned above, the formed products are advantageously manufactured using a deep-drawing process. This is preferably done using pressure and heat in the areas mentioned above.

[0021] The aforementioned and further advantages of the present invention will be explained in more detail with reference to the following exemplary embodiment.

[0022] From highly bleached, long-fiber softwood pulp with a fiber length of 3 mm to 4 mm, a pulp is first formed by pulping with water in a pulper. The resulting pulp-water mixture is fed into a paper machine and applied to a continuous wire. Right at the beginning of the paper machine, a vacuum-operated suction roll removes a large portion of the water from the pulp-water mixture, thus forming cellulose wadding on the continuous wire. Further dewatering elements in the paper machine ensure further drying of the resulting single-ply cellulose wadding. The still-moist single-ply cellulose wadding is couched off the continuous wire and transported to a downstream drying section of the paper machine. This section includes a steam-heated drying cylinder and a steam hood that uses hot air to dry the single-ply cellulose wadding.The single-layer cellulose wadding obtained in this manner had a moisture content of approximately 3% to 6.5% according to DIN EN ISO 12625-8 (April 2011). This wadding is scraped from the drying cylinder and wound onto a reel. During winding, a crepe factor of approximately 45% to 55% was achieved by varying the speeds of the drying cylinder and the roller used for winding. The elongation at break of the resulting single-layer cellulose wadding was approximately 60% to 85% according to DIN EN ISO 12625-4 (March 2017). The basis weight of the single-layer cellulose wadding web was approximately 31 g / m².After removing the single-layer cellulose wadding produced as described above, it was formed into eight layers by folding the single layer back four times or by unwinding eight individual layers of cellulose wadding and stacking them on top of each other. Water was added to the inner layers of cellulose wadding by spraying to achieve a moisture content of approximately 20% in the eight-layer cellulose wadding. Finally, the eight-layer cellulose wadding, which had a thickness of approximately 2.8 mm, was cut into narrow rolls.

[0023] A cellulose wadding produced in this way can then, for example by doubling it by folding back or layering two sheets of eight-layer cellulose wadding on top of each other, thus creating a sixteen-layer sheet, be formed in a deep-drawing process into, for example, a tray for packaging fruit, sausage or cheese.

Claims

1. Use of at least a single layer of cellulose wadding comprising cellulose in the form of a web or in the form of blanks for the manufacture of formed products.

2. Use according to claim 1, characterized by the fact that which includes at least one layer of long-fiber cellulose wadding.

3. Use according to one or more of the preceding claims, characterized by the fact that The products are packaging materials.

4. Use according to one or more of the preceding claims, characterized by the fact that The cellulose used to produce the cellulose wadding has a fiber length in the range of approximately 1 mm to approximately 5.5 mm.

5. Use according to one or more of the preceding claims, characterized by the fact that One layer of cellulose wadding has a thickness according to DIN EN ISO 12625-3 (September 2014) in a range of approximately 0.12 mm to approximately 0.68 mm.

6. Use according to one or more of the preceding claims, through this characterized that The cellulose wadding has a thickness according to DIN EN ISO 12625-3 (September 2014) in a range of approximately 0.5 mm to approximately 70 mm before forming.

7. Use according to one or more of the preceding claims, through this characterized that the cellulose wadding is formed in at least four layers.

8. Use according to one or more of the preceding claims, characterized by the fact that The at least single-layer cellulose wadding has a basis weight in the range of approximately 16 g / m² 2 up to about 50 g / m² 2 exhibits.

9. Use according to one or more of the preceding claims, through this characterized that The cellulose wadding has a crepe factor in a range of approximately 15% to approximately 80%.

10. Use according to one or more of the preceding claims, characterized by the fact that The cellulose wadding has a moisture content according to DIN EN ISO 12625-8 (April 2011) in a range of approximately 3% to approximately 40%.

11. Use according to one or more of the preceding claims, characterized by the fact that the cellulose used to produce the cellulose wadding is bleached and / or unbleached.

12. Use according to one or more of the preceding claims, characterized by the fact that The cellulose wadding has an elongation at break according to DIN EN ISO 12625-4 (March 2017) in a range of approximately 15% to approximately 180%.

13. Use according to one or more of the preceding claims, characterized by the fact that In a multi-layered design, the cellulose wadding must have a moisture content of at least one inner layer higher than the moisture content of the outer layers before forming.

14. Use according to one or more of the preceding claims, characterized by the fact that The products are manufactured using a deep-drawing process.

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