A method for producing a cellulose product and a cellulose product

Abstract

A High Density Dry Moulded Fibre (HD-DMF) tube-shaped cellulose product (1) and a method for producing such a tube-shaped cellulose product (1) from a cellulose material (2), where the forming mould (3) comprises a first mould part (4) having a cavity (8), a second mould part (5) having a shaft (9), and a third mould part (6) having a tube-shaped pressing member (10), wherein the method comprises the steps of; arranging the shaft (9) in the cavity (8), thereby creating a tube-shaped forming space (11); arranging the cellulose material (2) in the tube-shaped forming space (11); and forming the tube-shaped cellulose product (1) by pressing the cellulose material (2) with the tube-shaped pressing member (10) with a forming pressure to obtain the tube-shaped cellulose product (1).

Description

[0001] A METHOD FOR PRODUCING A CELLULOSE PRODUCT AND A

[0002] CELLULOSE PRODUCT

[0003] TECHNICAL FIELD

[0004] The present disclosure relates to a method for producing a high density dry moulded fibre (HD-DMF) tube-shaped cellulose product from a cellulose material comprising cellulose fibres.

[0005] BACKGROUND

[0006] Cellulose fibres are often used as raw material for producing or manufacturing various products. Products formed of cellulose fibres can be used in many different situations where there is a need for having sustainable products of essentially non-flat shapes. An essentially non-flat shapes may refer to any suitable three-dimensional object shape. There is a wide range of products that can be produced from cellulose fibres and a few examples are disposable plates and cups, blank structures and packaging materials. Packages produced from cellulose fibres may for example be used for packaging of liquids, dry materials and other types of goods, where the packaging may be made in a three-dimensional shape or formed into a three-dimensional shape from a two-dimensional sheet material. Such products are often laminated with different films in order for the product to withstand liquids, grease, heat etc.

[0007] Cellulose fibres are obtained by separating the cellulose fibres from a pulp derived from e.g. wood or other plants. Pulp is a lignocellulosic fibrous material that can be prepared either mechanically or chemically by separating cellulose fibres from wood or other plants. Wood pulp is e.g. obtained by grinding timber or trees in some kind of mill, e.g. a disc refiner, where the wood is ground to wood pulp. The pulp contains water, cellulose fibres, lignin and hemicelluloses. For some products, e.g. where the strength is not a key factor and / or when a low price is important, a lignocellulosic material, i.e. fibres where the lignin is not removed, can be used. There are different processes that can separate wood fibres. When preparing mechanical pulp, thermomechanical pulp or chemo-thermomechanical pulp, the fibres are separated but the lignin is not removed from the cellulose fibres. In a chemical pulp process, the lignin and some of the hemicelluloses is removed more or less completely from the pulp, leaving substantially pure cellulose fibres.

[0008] One material commonly used for cellulose fibre products is wet moulded pulp. The pulp used for wet forming is often obtained from recycled paper boards and newspaper, where the cellulose fibres comprise lignin. This lowers the cost. Wet moulded pulp has the advantage of being considered as a sustainable packaging material, since it is produced from biomaterials and can often be recycled or composted after use. Consequently, wet moulded pulp has been quickly increasing in popularity for different applications. Wet moulded pulp articles are generally formed by immersing a suction mould into a liquid or semi liquid pulp suspension or slurry, while suction is applied, whereby a body of pulp is formed with the shape of the desired product by fibre deposition. The suction mould is then withdrawn from the suspension and the suction is generally continued to compact the deposited fibres while exhausting residual liquid. With all wet-forming techniques there is a need for drying of the wet moulded product, where the drying is a very time and energy consuming part of the production, which is costly. Further, this method requires a large quantity of water. The demands on aesthetical, chemical and mechanical properties of products are increasing, and due to the properties of wet-formed cellulose products, the mechanical strength, flexibility, and chemical properties are limited. It is also difficult in the wet-forming process to control the mechanical properties of the products with high precision.

[0009] Another known method for producing products from cellulose material is by pressing loose cellulose fibres in a dry state, known as Dry Moulded Fibres (DMF). These products can be made in a cost-efficient way without using water as a cellulose fibre bearer and with a reduced energy need. Such products can be used to replace disposable plastic products, but are somewhat limited when it comes to strength and the possibility to vary the thickness of a product to a great extent. A Dry Moulded Fibres product is produced from an air-laid cellulose fibre structure where the cellulose fibre structure is pressed in a forming mould to a three-dimensional cellulose product.

[0010] In a DMF process, cellulose fibres are formed with a forming pressure between 10-20 MPa in a regular compression mould. In such forming, the cellulose fibres arranged in a cellulose fluff blank are drawn apart somewhat when a non-flat shape is created. If the shape or height difference is too large, the cellulose blank may be torn, which is one reason why deep drawn dry moulded fibre products are difficult to produce. Since the cellulose blank does not float or stretch, it is also difficult to produce dry moulded cellulose products where the difference in thickness varies over the cellulose product. DMF products can be produced at the same cost as disposable plastic products.

[0011] There is thus a need for improved sustainable cellulose products, where the cellulose products are having improved mechanical and chemical properties, can be manufactured with high precision, and where the production is costefficient and rational.

[0012] SUMMARY

[0013] An object of the present disclosure is to provide a method for producing a tubeshaped cellulose product where the previously mentioned problems are avoided. This object is at least partly achieved by the features of the independent claim. The dependent claims contain further developments of the method for producing a tube-shaped cellulose product. Another object of the present disclosure is to provide a tube-shaped cellulose product.

[0014] The disclosure concerns a method for producing a High Density Dry Moulded Fibre tube-shaped cellulose product from a cellulose material, where the forming mould comprises a first mould part, a second mould part and a third mould part, where the first mould part comprises a cavity, where the second mould part comprises a shaft, and where the third mould part comprises a tube-shaped pressing member arranged around the shaft of the second mould part, wherein the method comprises the steps of; arranging the shaft of the second mould part in the cavity of the first mould part, thereby creating a tube-shaped forming space between the first mould part and the second mould part; arranging the cellulose material in the tube-shaped forming space of the forming mould; and forming the tube-shaped cellulose product from the cellulose material in the forming mould, by pressing the cellulose material in a pressing action with the tube-shaped pressing member of the third mould part with a forming pressure to obtain the tube-shaped cellulose product.

[0015] One advantage of the method is that the pressing member has a relatively small pressing surface that enables transformation of a pressing force from a relatively small press of e.g. 1 -2 tons to a very high forming pressure.

[0016] According to one example, the forming pressure is at least 100 MPa.

[0017] According to one example, the forming pressure is at least 200 MPa.

[0018] According to one example, the tube-shaped forming space is obtained by bearing a shaft lower end of the second mould part on a cavity bottom wall of the first mould part or by extending the shaft lower end of the second mould part through an opening in the cavity bottom wall of the first mould part.

[0019] According to one example, the pressing of the cellulose material includes rotating and / or vibrating the first mould part and / or the second mould part and / or the third mould part of the forming mould during the pressing action. According to one example, the rotation and / or vibration of the first mould part and / or the second mould part and / or the third mould part takes place during the closing stroke of the pressing action.

[0020] According to one example, the rotation and / or vibration of the first mould part and / or the second mould part and / or the third mould part of the forming mould includes a plurality of back-and-forth movements.

[0021] According to one example, the temperature of the cellulose material is controlled to a predefined temperature during the pressing action, wherein the predefined temperature is in the range of 50-300 °C.

[0022] According to one example, the shape of the cavity of the first mould part, the shape of the shaft of the second mould part and the shape of the tube-shaped pressing member of the third mould part is circular. Other forms and shapes than circular is also possible in order to create non-circular tube-shaped cellulose products.

[0023] According to one example, the cellulose material contains less than 20% water by weight. Preferably, the cellulose material contains between 8-12% water by weight.

[0024] According to one example, the cellulose material comprises at least 90% cellulose fibres by dry weight. It should be noted that the remaining 10% is free from environmentally hazardous substances and compounds.

[0025] According to one example, the cellulose material comprises cellulose fibres and at least one additive. The additive is not intended to act as a binder between the fibres since it contradicts the idea of dry moulding the fibres. The process of dry moulding fibres relies on the forming of hydrogen bonds between the fibres. The invention also relates to a cellulose product forming mould for dry-forming a High Density Dry Moulded Fibre tube-shaped cellulose product from a cellulose material, wherein the product forming mould comprises a first mould part, a second mould part and a third mould part, where the first mould part comprises a cavity, where the second mould part comprises a shaft, and where the third mould part comprises a tube-shaped pressing member, wherein the shaft of the second mould part is configured to be arranged in the cavity of the first mould part, thereby creating a tube-shaped forming space between the first mould part and the second mould part; that the tube-shaped pressing member of the third mould part is arranged around the shaft of the second mould part, and that the forming mould is configured to press cellulose material arranged in the tube-shaped forming space with a pressing surface of the tubeshaped pressing member with a forming pressure to obtain the tube-shaped cellulose product.

[0026] The invention also relates to a High Density Dry Moulded Fibre tube-shaped cellulose product formed from a cellulose material, wherein the tube-shaped cellulose product has a density greater than 1 ,30 g / cm3According to one example, the tube-shaped cellulose product has a smooth inner surface, i.e. inner wall surface, and / or a smooth outer surface, i.e. outer wall surface. According to one example, the tube-shaped cellulose product has a threaded inner surface and / or a threaded outer surface. Hence, the method and apparatus according to the invention can be configured to manufacture various kind of products with high density and thus great properties and performance comparable to similar plastic products.

[0027] According to one example, the tube-shaped cellulose product has a wall thickness of the tube-shaped cellulose product that varies with at least 200%.

[0028] According to one example, the tube-shaped cellulose product comprises a lower end portion, an upper end portion and a side wall having an outer wall surface and an inner wall surface, where the outer wall surface and / or the inner wall surface is provided with at least one protruding element. Here, the shaft outer surface comprises indentations corresponding to the protruding element of the inner wall surface of the cellulose product. In another example, the outer wall surface of the cellulose product is provided with at least one protruding element and, in a similar manner as the shaft outer surface comprises indentations in the example above, the cavity side wall comprises indentations corresponding to the protruding elements in the outer wall surface. In one example the outer wall surface and the inner wall surface comprises protruding elements, and then the cavity side wall comprises indentations and the shaft outer surface comprises indentations correspondingly.

[0029] According to one example, the lower end portion and / or the upper end portion of the product is provided with at least one protruding element. When the lower end portion is provided with at least one protruding element, then the cavity bottom wall comprises corresponding indentations. When the upper end portion is provided with at least one protruding element, then the pressing surface of the pressing member comprises corresponding indentations. When the lower end portion is provided with at least one protruding element and the upper end portion is provided with at least one protruding element, then the cavity bottom wall comprises corresponding indentations and the pressing surface of the pressing member comprises corresponding indentations.

[0030] The cellulose material comprises at least 50% cellulose fibres. The material may e.g. be wood fibres comprising some lignin and hemicellulose, or may comprise cellulose fibres and some additives.

[0031] Advantages with these features are that the method provides an efficient manufacturing process for cellulose products with improved mechanical and chemical properties, where a tube-shaped cellulose product is a high density dry moulded fibre (HD-DMF) product. The advantage with this method is that high density dry moulded fibre products are provided, having a higher strength than regular dry moulded fibre (DMF) products that are moulded with a forming pressure in a range between 10-30 MPa. The forming pressure is greater than 100 MPa, preferably greater than 150 MPa, and preferably greater than 200 MPa or more.

[0032] With a sufficiently high forming pressure and with a possible rotational and / or vibrating movement, the cellulose material will flow in the forming mould. In this way, cellulose products having more complicated shapes that are not possible to obtain by regular dry moulded fibres forming can be produced. It is e.g. possible to provide cellulose products having a wall thickness that varies with more than 200%. One example of such a cellulose product is a screw cap for a beverage bottle, where the cap comprises an internal thread adapted to interact with a thread of a bottle neck. Another product suitable to produce with the inventive method is a coffee capsule, where the coffee capsule is deep drawn. Due to the flow of the cellulose material, a thin, deep cellulose capsule can be obtained. The inventive method further allows for cellulose products having sections with different thicknesses, such that the rim of the capsule may be thicker than the side wall, and such that the bottom of the capsule may comprise thinner sections that are easier to penetrate. In a screw cap, the thickness of a threaded section is around twice as a non-threaded section.

[0033] A further advantage of the inventive method is that the forming mould must not be filled evenly with cellulose material before the pressing action, as is the case with the regular dry moulded fibres method. Due to the shear forces acting on the cellulose material during the pressing action, the cellulose material will flow into all regions of the forming mould, filling the forming mould evenly with cellulose material. In one example, cellulose material is arranged as a tube-shaped cellulose pre-form, made e.g. from a roll of thin paper, a roll of pulp or from pre-pressed fluff pulp. It is important that the correct amount of cellulose material is used when a forming mould having a predefined volume is used, but the exact positioning of the cellulose material is not very important with the inventive method.

[0034] The moulding of a HD-DMF product is in one example performed in a closed mould having a predefined volume, where the cellulose material is completely enclosed by the mould. During a moulding action with a high forming pressure, where the forming pressure exceeds 100 MPa, the forces acting on the cellulose fibres will not only provide a compressing force but also a shear force on the cellulose fibres when a three-dimensional product is moulded, since the cellulose fibres will be displaced somewhat. The shear forces acting on the cellulose fibres will to some extent transform some of the cellulose fibres to micro fibrils and nano-cellulose. This process will be accelerated by introducing shear forces to the cellulose material through rotation and / or vibration of one or more of the forming mould parts relative to other forming mould parts during the pressing action. The high pressure and the rotational and / or vibration movement will allow the cellulose material to flow and to fill the forming mould completely. In this way, relatively complicated circular or non-circular cellulose products can be obtained. By rotating and / or vibrating one or more of the forming mould parts, the cellulose material in the forming mould will be exposed to shear forces that allows the cellulose fibres to flow.

[0035] In one example, the forming pressure is higher than 150 MPa and may be higher than 200 MPa or higher, depending on the produced cellulose product. The forming pressure may be up to 500 MPa or even up to 1000 MPa or more, depending on the intended use and the actual cellulose product. If various additives are used in the cellulose material, this may also impact the most suitable forming pressure. The density of the moulded cellulose product is greater than 1 ,30 g / cm3and may be up to 1 ,40 g / cm3or even higher. Tests have shown that a density of a moulded cellulose product greater than 1 ,40 g / cm3or more is possible to achieve, and densities can come close to the upper limit of 1 .6 g / cm3for crystalline cellulose.

[0036] A higher forming pressure will give a cellulose product with a higher strength and a higher density. By exposing the cellulose material to shear forces by rotating and / or vibrating one or more of the forming mould parts during the pressing action, a cellulose product having the same properties can be achieved with a reduced forming pressure. The rotation and / or vibration of a forming mould part is performed during the pressing action by rotating and / or vibrating one of the forming mould parts with e.g. a hydraulic or electrical rotational device. The rotational or vibration device may be integrated directly with the forming mould part, or may be arranged outside of the forming mould part, at the holder plate for the forming mould part.

[0037] The degree of rotation is in one example at least 60 degrees, and may be up to 720 degrees or more. The rotational speed is relatively low, and may e.g. be between 1 -120 rpm. The rotation may be performed during the closing stroke of the forming mould and / or when the forming mould is completely closed, such that the rotation is performed when the forming pressure is high. The rotation device may be a mechanical, a servo-hydraulic, an electrohydraulic or an electrical rotation device. It is also possible to rotate one of the forming mould parts continuously with a rotating motor. In this way, the rotation does not have to start and stop during a pressing action.

[0038] In one example, one part of the forming mould is rotated in a first rotational direction during the pressing action. This would e.g. be suitable when producing a screw cap having an internal thread. By rotating the forming mould a few degrees in a second rotational direction when the forming mould is opened, the screw cap will be released some from the first forming mould part, such that the screw cap is easier to release completely from the first forming mould part when the forming mould has returned to the initial position.

[0039] The vibrations introduced to the forming mould are in one example created by a vibration device integrated in one of the mould parts of the forming mould. The vibration device may be integrated directly into the forming mould part, may be positioned in the holder plate for the forming mould part or may be arranged at the forming press, e.g. by controlling the hydraulic press cylinder. By positioning the vibration device in the holder plate or at the forming press, the same vibration device can be used for different forming moulds, where a forming mould part is attached to the holder plate. A further advantage of positioning the vibration device to the holder plate or at the forming press is that the vibration device must not be exposed to the heat of the forming mould. There is an insulation between the holder plate and the forming mould. A further advantage is that forming moulds of different sizes and shapes can be attached to the same holder plate, which reduces the need for several vibration devices.

[0040] For relatively low frequency vibration, typically below 100 Hz, servohydraulic or electrohydraulic devices can be used. For frequencies typically between 1 Hz to 2000 Hz, electrodynamic devices can be used. In one example, the vibrations have a relatively low frequency, in the range between a few Hz up to 100 Hz. The vibrations are superimposed on the regular forming pressure, where the initial forming pressure preferably is above 100 MPa or more. The waveform of the vibrations is not crucial, and a sinusoidal waveform or a triangular waveform may be used. The stroke of the vibration device may be relatively short, from parts of a mm up to a few mm. The total energy of the vibrations is a combination of pressure, frequency and stroke length. A rotational vibration over a few degrees up to 30 degrees or more is preferred.

[0041] It is also possible to position a vibration device at the lower end of the first forming mould part such that it can act directly on the cellulose fibres, e.g. a piezo device. Such a device is capable of producing vibration frequencies of up to 20 kHz or more. The used vibration speed and the used amplitude will depend on the size and shape of the cellulose product. A higher frequency and / or higher amplitude may e.g. be required for cellulose products having thinner side walls. The vibrations are introduced to the cellulose fibres at the same time as the rotational movement, e.g. during the closing stroke of the pressing action and / or when the forming mould is closed. The vibrations may continue during the holding time of the pressing cycle, but are shut off during the opening stroke of the pressing action. The direction of the vibrations may also vary, and may be axial, rotational, translational or a combination of these. The high pressure and the shear forces acting on the cellulose fibres due to the rotational and / or vibrational movement allows the cellulose fibres to flow in the forming mould. This may be referred to as burst flow. After a specified holding time, which may be very low, the cellulose product is ready and can be removed from the forming mould.

[0042] The temperature of the cellulose material is preferably above 50 degrees Celsius during the pressing action. The temperature should not exceed 300 degrees Celsius. The temperature of the cellulose material is controlled to a predefined temperature during the pressing action, wherein the predefined temperature is in the range of 50-300 °C

[0043] The material used for the cellulose product preferably comprises natural cellulose fibres and may further comprise other substances. If the material is wood, the material comprises cellulose fibres, lignin and hemicellulose. The material is in one example wood pulp, a fibrous lignocellulosic material prepared from wood or other plants by chemically, semi-chemically or mechanically treatment of the material. Such a material may e.g. comprise between 50-99% cellulose fibres.

[0044] The material used may also comprise cellulose fibres and some additives, such as different barrier materials that are intended to increase the resistance of the cellulose product to withstand liquids, grease, oil, heat etc. The additives are preferably mixed into the cellulose material such that the cellulose material comprises a homogenous mixture of the different ingredients. Other additives that may be used could be additives that increase the strength of the cellulose product, or additives that increase the flowability of the material during the pressing action.

[0045] The cellulose material will also comprise some water. A water content between 2-25% may be used, depending on the actual cellulose material used. A too low water content will reduce the possibility to form hydrogen bonds between the cellulose fibres. In one example, the water content of the cellulose blank is in the range between 8-12% by weight.

[0046] It is of advantage that the forming pressure is as low as possible to obtain a cellulose product with the required properties. By rotating and / or vibrating at least one forming mould part in combination with a high forming pressure, the forming pressure can be reduced when compared to a regular axial pressing action. The rotational and / or vibrational movement will increase the shear forces between the cellulose fibres in the cellulose material. With enough shear forces acting on the cellulose fibres, the cellulose material will flow and will be able to fill the forming mould completely, even if the shape of the forming mould is relatively complicated with varying wall thickness, threads, gripping surfaces etc. This is opposed to regular dry moulded fibre forming, where an air-formed cellulose mat structure is pressed in a forming mould. In such a method, the cellulose mat structure is compacted to a cellulose product having substantially the same wall thickness and having a density below 1 ,30 g / cm3

[0047] The cellulose product may be formed in a closed mould having a specified volume, where a predefined amount of material will be inserted and pressed. This will give a cellulose product having a predefined volume, shape and density. By selecting the pressing parameters correctly, a cellulose product having a density higher than 1 ,30 g / cm3is obtained. It is important that the correct amount of material is used in such a forming mould in order to obtain a cellulose product with the desired density. With a too low material content, there will not be enough shear forces acting on the cellulose fibres. When enough material is used in the forming mould, the material will flow, which will give a cellulose product with a density of at least 1 ,30 g / cm3. More material will give a higher density, up to a maximal value, depending on the used forming pressure and the degree of rotation.

[0048] The preferred forming pressure is a forming pressure where the desired parameters for the cellulose product are met, without exceeding these parameters. A higher forming pressure adds a cost to the cellulose product. This means that in the same press with the same rated pressure, fewer and / or smaller cellulose products can be made with the same forming pressure. There is thus a need to optimize the used forming pressure to the desired properties of the cellulose product. It has been shown that a forming pressure exceeding approximately 100 MPa will allow the cellulose material to flow, which allows for a HD-DMF product having a more complicated shape and a varying thickness. By rotating and / or vibrating one or more of the forming mould parts, the used forming pressure can be reduced.

[0049] One advantage with a higher forming pressure where the cellulose material assumes liquid-like properties is that complicated shapes can be obtained, which are difficult to obtain with regular moulding of DMF products. With the inventive method, more complicated product such as a lid having internal threads and a smooth outer surface can be produced, where the wall thickness of the lid varies with up to 300-400% or more.

[0050] The cellulose product is formed in a forming mould which comprises a first mould part, a second mould part and a third mould part. The forming mould parts are non-flexible, preferably made from steel, and may be heated to the desired forming temperature. The forming mould is in one example heated with integrated heating elements, preferably electrical heating elements, but also liquid heating is possible. The forming mould is in one example provided with a closed volume, such that the density depends on the used amount of cellulose material. In another example, the forming mould is pressure controlled, such that the density depends on the forming pressure and not on the amount of cellulose material.

[0051] The cellulose material is in one example an air-laid cellulose blank structure used for regular dry moulded fibre products. Here, the cellulose material may be pre-pressed in a pre-forming mould with a low pre-forming pressure in the range between 1 - 10 MPa. The purpose of the pre-forming is to compress the cellulose material to a smaller volume such that it will be easier to insert the pre-formed cellulose material into the forming mould. In another example, the cellulose starting material is a cellulose cardboard paper or pulp sheet containing either substantially only cellulose fibres or cellulose fibres and additives. The cardboard paper or pulp sheet may be stacked in several layers in order to obtain a desired amount of cellulose material.

[0052] During the moulding of a HD-DMF tube-shaped cellulose product, different forces will act on the cellulose material. By rotating and / or vibrating one or more of the forming mould parts, shear forces will act on the cellulose material. The shear forces, together with the high forming pressure, temperature and possible movements of one or more of the mould parts, will allow the cellulose fibres to flow in the forming mould.

[0053] The cellulose material may be made from mechanical pulp, thermochemical pulp or chemical pulp comprising at least some lignin and / or hemicellulose, also referred to as a lignocellulosic raw material. The cellulose material may in one example comprise more than 0,5% lignin. The cellulose material may be a lignocellulosic material comprising both lignin and hemicellulose, e.g. made from mechanical pulp. The cellulose material may also include additives, where the additives are used to decrease the liquid and / or gas permeability of the cellulose product and to increase the resistance to e.g. hot and cold liquids, grease, oil etc. Such additives may also be applied to the surface of the cellulose product after the cellulose product is formed. In one example, the cellulose material comprises at least 90% cellulose fibres by dry weight. The additives used are additives adapted to alter the permeability of the cellulose material, and should not function as a binder material to bind the cellulose material together. By using untreated cellulose fibres, the cellulose fibres are bound together by hydrogen bonds and Van der Vaals bonds. Additives may decrease the possibility for hydrogen bonds, and a binder material will definitely reduce the number of hydrogen bonds.

[0054] One suitable product made from cellulose HD-DMF is a screw cap for a bottle. The screw cap is provided with a top section and a concentric side wall having an inner surface and an outer surface, where the inner surface is provided with at least one internal thread section and where the circumferential outer surface is substantially even. Such a cellulose HD-DMF screw cap will resemble a regular plastic screw cap used for e.g. PET plastic bottles. The internal thread section may be a single thread or may comprise several thread sections that constitutes a screw thread. With the inventive method, a cellulose HD-DMF product where the thickness of the product varies with at least 200% can be obtained. A thickness variation up to 300-400% or more is possible if desired. In this way, it is possible to provide an internal thread on the inner surface of the screw cap, while the outer surface can be substantially smooth and even. It is of course also possible to provide the outer surface of the screw cap with some kind of gripping surface, a gripping rim and / or a tamper proof fixation rim. Another suitable product is a flip-lid used on containers that are not provided with a thread.

[0055] The cellulose HD-DMF product is formed in the forming mould during a cycle time period in the range of 0,1 to 10 seconds, and preferably less than 5,0 seconds. A suitable holding time for the product in the forming mould is less than a second, and may be e.g. 0,3-0, 7 seconds. The holding time together with the forming temperature, the forming pressure, humidity and the rotational movement are important parameters in the forming of the HD-DMF cellulose product.

[0056] BRIEF DESCRIPTION OF DRAWINGS

[0057] The disclosure will be described in greater detail in the following, with reference to the attached drawings, in which

[0058] Figs. 1 a-h schematically show a first example of a progression of a method and a forming apparatus comprising a cellulose product forming mould for dry-forming a High Density Dry Moulded Fibre tubeshaped cellulose product from a cellulose material, Figs. 2a-d schematically show a second example of a progression of a method and a forming apparatus comprising a cellulose product forming mould for dry-forming a High Density Dry Moulded Fibre tube-shaped cellulose product from a cellulose material, and

[0059] Figs. 3a-i schematically show an example of an industrial realisation of a manufacturing apparatus comprising a forming apparatus comprising a cellulose product forming mould according any one of the examples in figures 1 a-h and 2a-d.

[0060] DESCRIPTION OF EXAMPLE EMBODIMENTS

[0061] Various aspects of the disclosure will hereinafter be described in conjunction with the appended drawings to illustrate and not to limit the disclosure, wherein like designations denote like elements, and variations of the described aspects are not restricted to the specifically shown embodiments, but are applicable on other variations of the disclosure.

[0062] In the present detailed description, a method for producing a tube-shaped cellulose HD-DMF product from a cellulose material will be described. The method is suitable for different products that should exhibit a higher strength and a higher density than regular DMF products, and that may have a more complicated shape with varying thickness. Such products may be relatively small with a volume of e.g. a few cm3due to the required high forming pressure, which is costly. It would of course also be possible to produce larger cellulose HD-DMF products if desired. The cellulose HD-DMF products are disposable, but may be used several times, depending on the actual product and actual post treatment of the product. The cellulose HD-DMF products may be recyclable and / or compostable.

[0063] The cellulose material used to form the cellulose HD-DMF product is a cellulose material comprising cellulose fibres and that may also comprise at least some lignin and hemicellulose. Such a material is produced from mechanical pulp, thermochemical pulp or chemical pulp where some of the lignin and the hemicelluloses can be removed. Additives may also be added to the cellulose material, where the additives are used to decrease the liquid and / or gas permeability of the cellulose product and to increase the resistance to e.g. hot and cold liquids, grease, oil etc. In one example, the cellulose material comprises at least 90% cellulose fibres by dry weight and at the most 10% lignin or additives by weight. The cellulose material may be a lignocellulosic material comprising both lignin and hemicellulose, e.g. made from mechanical pulp. The cellulose material will also comprise some water, e.g. between 6% to 25% by weight. Water is not seen as an additive, it is necessary to create hydrogen bounds between the cellulose fibres but will evaporate when the cellulose product is heated in an oven. In one example, the water content of the cellulose material is in the range between 8-12% by weight.

[0064] Figs. 1 a-h schematically show a first example of a progression of a method and a forming apparatus comprising a cellulose product forming mould for dry-forming a High Density Dry Moulded Fibre tubeshaped cellulose product from a cellulose material.

[0065] Figs. 2a-d schematically show a second example of a progression of a method and a forming apparatus comprising a cellulose product forming mould for dry-forming a High Density Dry Moulded Fibre tube-shaped cellulose product from a cellulose material, and

[0066] Figs. 3a-i schematically show an example of an industrial realisation of a manufacturing apparatus comprising a forming apparatus comprising a cellulose product forming mould according any one of the examples in figures 1 a-h and 2a-d.

[0067] Figures 1a-h, 2a-d and 3a-i schematically show a method and a device configured to produce a High Density Dry Moulded Fibre tube-shaped cellulose product 1 from a cellulose material 2, where the forming mould 3 comprises a first mould part 4, a second mould part 5 and a third mould part 6, where the first mould part 4 comprises a cavity 8, where the second mould part 5 comprises a shaft 9, and where the third mould part 6 comprises a tubeshaped pressing member 10 arranged around the shaft 9 of the second mould part 5, wherein the method comprises the steps of; arranging the shaft 9 of the second mould part 5 in the cavity 8 of the first mould part 4, thereby creating a tube-shaped forming space 11 between the first mould part 4 and the second mould part 5; arranging the cellulose material 2 in the tube-shaped forming space 11 of the forming mould 3; and forming the tube-shaped cellulose product 1 from the cellulose material 2 in the forming mould 3, by pressing the cellulose material 2 in a pressing action with the tube-shaped pressing member 10 of the third mould part 6 with a forming pressure to obtain the tube-shaped cellulose product 1 .

[0068] One advantage of the method is that the pressing member has a relatively small pressing surface that enables transformation of a pressing force from a relatively small press of e.g. 1 -2 tons to a very high forming pressure.

[0069] According to one example, the forming pressure is at least 100 MPa.

[0070] According to one example, the forming pressure is at least 200 MPa.

[0071] According to one example, the tube-shaped forming space 11 is obtained by bearing a shaft lower end 14 of the second mould part 5 on a cavity bottom wall 12 of the first mould part 4, as can be seen in figures 1 a-1 h, or by extending the shaft lower end 14 of the second mould part 5 through an opening in the cavity bottom wall 12 of the first mould part 4, as can be seen in figures 2a-2d. According to one example, the pressing of the cellulose material 2 includes rotating and / or vibrating the first mould part 4 and / or the second mould part 5 and / or the third mould part 6 of the forming mould 3 during the pressing action.

[0072] According to one example, the rotation and / or vibration of the first mould part 4 and / or the second mould part 5 and / or the third mould part 6 takes place during the closing stroke of the pressing action.

[0073] According to one example, the rotation and / or vibration of the first mould part 4 and / or the second mould part 5 and / or the third mould part 5 of the forming mould 3 includes a plurality of back-and-forth movements.

[0074] Figures 1 c, 1 d, 2c, 2d, 3b, 3c and 3h show that the first mould part 4 is moved back and forth in a rotational movement about the shaft 9. As described above, other relative movements are possible, e.g. ultrasonic vibration of the shaft in the longitudinal, the transverse and / or the rotational direction. The advantage of the relative motion is that the cellulose material is subjected to stress that causes the cellulose material to assume liquid-like properties that allows for the cellulose material to flow into and conform to the forming space 11 .

[0075] According to one example, the temperature of the cellulose material 2 is controlled to a predefined temperature during the pressing action, wherein the predefined temperature is in the range of 50-300 °C.

[0076] According to one example, the shape of the cavity 8 of the first mould part 4, the shape of the shaft 9 of the second mould part 5 and the shape of the tubeshaped pressing member 10 of the third mould part 6 is circular. Other forms and shapes than circular is also possible in order to create non-circular tubeshaped cellulose products 1 . According to one example, the cellulose material 2 contains less than 20% water by weight. Preferably, the cellulose material 2 contains between 8-12% water by weight.

[0077] According to one example, the cellulose material comprises at least 90% cellulose fibres by dry weight. It should be noted that the remaining 10% is free from environmentally hazardous substances and compounds.

[0078] According to one example, the cellulose material comprises cellulose fibres and at least one additive. The additive is not intended to act as a binder between the fibres since it contradicts the idea of dry moulding the fibres. The process of dry moulding fibres rely on the forming hydrogen bonds between the fibres.

[0079] Figures 1 a-h, 2a-d and 3a-i further schematically show a cellulose product forming mould 3 for dry-forming a High Density Dry Moulded Fibre tubeshaped cellulose product 1 from a cellulose material 2, wherein the product forming mould 3 comprises a first mould part 4, a second mould part 5 and a third mould part 6, where the first mould part 4 comprises a cavity 8, where the second mould part 5 comprises a shaft 9, and where the third mould part 6 comprises a tube-shaped pressing member 10, wherein the shaft 9 of the second mould part 5 is configured to be arranged in the cavity 8 of the first mould part 4, thereby creating a tube-shaped forming space 11 between the first mould part 4 and the second mould part 5; that the tube-shaped pressing member 10 of the third mould part 6 is arranged around the shaft 9 of the second mould part 5, and that the forming mould 3 is configured to press cellulose material 2 arranged in the tube-shaped forming space 11 with a pressing surface 17 of the tube-shaped pressing member 10 with a forming pressure to obtain the tube-shaped cellulose product 1 .

[0080] Figures 1 g and 1 h schematically show two examples of a High Density Dry Moulded Fibre tube-shaped cellulose product 1 formed from a cellulose material 2, wherein the tube-shaped cellulose product 1 has a density greater than 1 ,30 g / cm3Figure 1 g shows a tube-shaped product 1 with a smooth inner surface 24 and a smooth outer surface 23. Figure 1 h shows a tube-shaped product 1 with a threaded inner surface 24. Hence, the method and apparatus according to the invention can be configured to manufacture various kind of products with high density and thus great properties and performance comparable to similar plastic products.

[0081] According to one example, the tube-shaped cellulose product has a wall thickness of the tube-shaped cellulose product that 1 varies with at least 200%.

[0082] According to one example, the tube-shaped cellulose product 1 comprises a lower end portion 20, an upper end portion 21 and a side wall 22 having an outer wall surface 23 and an inner wall surface 24, where the outer wall surface 23 and / or the inner wall surface 24 is provided with at least one protruding element 25, see figure 1 h. Figure 1 h shows that the shaft outer surface 16 comprises indentations corresponding to the protruding element 25 of the inner wall surface 24 of the cellulose product 1 . In another example, not shown, the outer wall surface 23 of the cellulose product 1 is provided with at least one protruding element and, in a similar manner as the shaft outer surface 16 comprises indentations in the example above, the cavity side wall 13 comprises indentations corresponding to the protruding elements in the outer wall surface 23. In one example, not shown, the outer wall surface 23 and the inner wall surface 24 comprises protruding elements, and then the cavity side wall 13 comprises indentations and the shaft outer surface 16 comprises indentations correspondingly.

[0083] According to one example, the lower end portion 20 and / or the upper end portion 21 of the product 1 is provided with at least one protruding element, not shown. When the lower end portion 20 is provided with at least one protruding element, then the cavity bottom wall 12 comprises corresponding indentations. When the upper end portion 21 is provided with at least one protruding element, then the pressing surface 17 of the pressing member comprises corresponding indentations. When the lower end portion 20 is provided with at least one protruding element and the upper end portion 21 is provided with at least one protruding element, then the cavity bottom wall 12 comprises corresponding indentations and the pressing surface 17 of the pressing member comprises corresponding indentations.

[0084] Figure 1 a schematically shows an example of a product forming mould 3 according to the above. Figure 1 a shows the forming mould in a cross- sectional side view, i.e. the cross-section is taken in plane described by a longitudinal direction X and a radial direction R. Figure 1 a shows the product forming mould 3 in an exploded view, i.e. all parts separated. Figure 1a shows that the first mould part 4 and the second mould 5 part are concentrically aligned about a centre axis 7, which allows for relative motion, e.g. rotation and / or vibration, of the first and second mould parts about the centre axis. The first mould part 4 comprises a cavity 8 defined by a cavity bottom wall 12 and a cavity side wall 13 extending from the cavity bottom wall 12. The shaft 9 comprises a shaft lower end 14 pointing in a direction towards the cavity 8 and a shaft upper end 15 pointing away from the cavity, and a shaft outer surface 16 between the shaft lower end 14 and the shaft upper end 15. The shaft outer surface 16 is an envelope surface configured to allow the pressing member 10 to move along, and when appropriate rotate, about the shaft. The pressing member 10 comprises: a pressing surface 17 pointing in a direction towards the cavity 8; an upper portion 17a pointing in a direction away from the cavity; an outer bearing surface 18 extending from the pressing surface 17 towards the upper portion 17a defining an envelope surface configured to bear against the cavity side wall 13 during the pressing action allowing relative motion of the pressing member 10 relative the cavity 8, i.e. the first mould part 4; an inner bearing surface 19 extending from the pressing surface 17 towards the upper portion 17a and defines a through channel of the pressing member 10 that is configured to bear against the shaft outer surface 16 allowing relative motion of the pressing member 10 about the shaft 9. Figures 1 a-h and figures 2a-d and figures 3a-i, show that the cellulose material 2 is in the form of a cylinder that is introduced over the shaft 9 before the shaft

[0085] 9 and pressing member 10 is introduced into the cavity 8, see especially figs. 1 b and 2b, 3a, 3f and 3g. This has the advantage that the amount, shape and position of the cellulose material is well controlled. The cellulose material 2 can for example be pre-formed into such a cylinder shape, or can be rolled onto the shaft 9 from a layer material.

[0086] In figure 1 b, the pressing member 10 is positioned in an upper position close to the shaft upper end 15 which allows for the cellulose material 2 to be positioned on the shaft 9 in a position closer to the cavity 8 than the pressing member 10. This is a pre-condition for the process since the pressing member

[0087] 10 shall move from the upper position towards the cavity bottom wall 12 about the shaft 9. In figure 1 c the shaft has moved into the cavity 8 and to an end position where the shaft lower end 14 presses against the cavity bottom wall 12 to form a tight seal so that the cellulose material cannot enter between the two parts. In a similar way, the tolerance between the outer bearing surface 18 and the cavity side wall 13 and the tolerance between the shaft outer surface 16 and the inner bearing surface 19 should be configured such that no or at least a minimum amount of cellulose material can enter the space created between the respective surfaces.

[0088] In figure 1 d, the condition described in figure 1 c prevail with the only difference that the pressing member 10 has moved from the upper position to an ultimate pressing position where the cellulose material is subject to the predetermined forming pressure described above. It should be noted that the predetermined forming pressure varies dependent on e.g. material and desired characteristics of the final product.

[0089] Figures 1 e-1 h shows the release process from the ultimate pressing position in figure 1d, same as figure 1 e, to the unmounting of the product in figure 1g or alternatively figure 1 h. Figure 1f shows that the second mould 5 and third mould part 6 is removed from the cavity 8 and the first mould part 1 , and that the pressing member 10 remains in a position distant from the upper position. In figures 1 g and 1 h the pressing member 10 has returned to its upper position and the cellulose product 1 has been released from the shaft 9. In figure 1 g, the inner and outer wall surfaces 23, 24 are smooth, which allows for the cellulose product to be released from the shaft 9 without need for any other movement than a straight gliding motion. In figure 1 h, the inner wall surfaces 23 comprises protruding elements 25, e.g. threads, which demands for the cellulose product 1 to be released from the shaft 9 with a rotating movement relative the shaft. Here, the relative motion can be done by rotation of the shaft 9 and / or the cellulose product 1 .

[0090] Figures 2a-d are similar to the figures 1 a-d, with the difference that the first mould part 4 comprises a cavity bottom wall through channel 8a in the cavity bottom wall 8 that allows for the shaft 9 to pass through the cavity bottom wall through channel 8a. The cavity bottom wall 12 then comprises a press portion 8b defined by the remaining portion of the cavity bottom wall between the through channel 8a and the cavity side wall 13. This allows for the pressing member 9 to remain in the upper position on the shaft 9, since the through motion of the shaft 9 allows for the pressing surface 17 to apply the predetermined forming pressure onto the cellulose material 2 and the press portion 8b. As an alternative to the cavity bottom wall through channel 8a, not shown, the through channel could be configured as a cavity configured to receive the shaft. Furthermore, in both the examples, the shaft 9 and the pressing member 10 could be attached to each other or be configured in one piece.

[0091] Figures 1 c, 1 d, 2c and 2d show that the tube-shaped forming space 11 is formed between the shaft outer surface 16 of the pressing member 10 and the cavity side wall 13. Figures 3a-i show a forming mould system comprising a forming mould 3 according to figures 1 a-h and 2a-d. In figures 3a-i the system comprises one first mould and two sets, a first set and a second set, of second and third mould parts. Each of the two sets comprises a pressing member 10 and a shaft 9 according to what has been described in connection to figs. 1 a-h and 2a-d. Each set is configured to move between a station configured to load cellulose material 2 to the shaft 9 before pressing action and receive a cellulose product

[0092] 1 from the shaft 9 after pressing action. Figures 3a-c show that the first set releases a cellulose product 1 to a first station and the second set initiates and performs the pressing action. Figures 3d-g show that the first set loads cellulose material 2 from the first station and moves into position for pressing action with the first mould part 4, and wherein the second set has released from the first mould part 4 and started to unload / release a cellulose product to the second station. Figures 3h-i show that the first set presses a cellulose product in the first mould part 4 while the second set loads cellulose material

[0093] 2 from the second station.

[0094] It will be appreciated that the above description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made, and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure is not limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims. Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand.

[0095] REFERENCE SIGNS

[0096] 1 : Cellulose product

[0097] 2: Cellulose material

[0098] 3: Forming mould

[0099] 4: First mould part

[0100] 5: Second mould part

[0101] 6: Third mould part

[0102] 7: Centre axis

[0103] 8: Cavity

[0104] 8a: Cavity bottom wall through channel

[0105] 8b: Press portion

[0106] 9: Shaft

[0107] 10: Tube-shaped pressing member

[0108] 11 : T ube-shaped form ing space

[0109] 12: Cavity bottom wall

[0110] 13: Cavity side wall

[0111] 14: Shaft lower end

[0112] 15: Shaft upper end

[0113] 16: Shaft outer surface

[0114] 17: Pressing surface

[0115] 17a: Upper portion of pressing member

[0116] 18: Outer bearing surface

[0117] 19: Inner bearing surface

[0118] 20: Lower end portion

[0119] 21 : Upper end portion

[0120] 22: Side wall

[0121] 23: Outer wall surface

[0122] 24: Inner wall surface

[0123] 25: Protruding element

Claims

29CLAIMS1. A method for producing a High Density Dry Moulded Fibre tube-shaped cellulose product (1 ) from a cellulose material (2), where the forming mould (3) comprises a first mould part (4), a second mould part (5) and a third mould part (6), where the first mould part (4) comprises a cavity (8), where the second mould part (5) comprises a shaft (9), and where the third mould part (6) comprises a tube-shaped pressing member (10) arranged around the shaft (9) of the second mould part (5), wherein the method comprises the steps of; arranging the shaft (9) of the second mould part (5) in the cavity (8) of the first mould part (4), thereby creating a tube-shaped forming space (11 ) between the first mould part (4) and the second mould part (5); arranging the cellulose material (2) in the tube-shaped forming space (11 ) of the forming mould (3); and forming the tube-shaped cellulose product (1 ) from the cellulose material (2) in the forming mould (3), by pressing the cellulose material (2) in a pressing action with the tube-shaped pressing member (10) of the third mould part (6) with a forming pressure to obtain the tube-shaped cellulose product (1 ).

2. A method according to claim 1 , wherein the forming pressure is at least 100 MPa.

3. A method according to claim 1 or 2, wherein the forming pressure is at least 200 MPa.

4. A method according to any of claims 1 to 3, where the tube-shaped forming space (11 ) is obtained by bearing a shaft lower end (14) of the second mould part (5) on a cavity bottom wall (12) of the first mould part (4) or by extending the shaft lower end (14) of the second mould part (5) through an opening in the cavity bottom wall305. A method according to any of claims 1 to 4, where the pressing of the cellulose material (2) includes rotating and / or vibrating the first mould part (4) and / or the second mould part (5) and / or the third mould part (6) of the forming mould (3) during the pressing action.

6. A method according to claim 5, wherein the rotation and / or vibration of the first mould part (4) and / or the second mould part (5) and / or the third mould part (6) takes place during the closing stroke of the pressing action.

7. A method according to claim 5 or 6, wherein the rotation and / or vibration of the first mould part (4) and / or the second mould part (5) and / or the third mould part (5) of the forming mould (3) includes a plurality of back-and-forth movements.

8. A method according to any of the preceding claims, wherein the temperature of the cellulose material (2) is controlled to a predefined temperature during the pressing action, wherein the predefined temperature is in the range of 50-300 °C.

9. A method according to any of the preceding claims, wherein the shape of the cavity (8) of the first mould part (4), the shape of the shaft (9) of the second mould part (5) and the shape of the tube-shaped pressing member (10) of the third mould part (6) is circular.

10. A method according to any of the preceding claims, wherein the cellulose material (2) contains less than 20% water by weight.11 . A method according to any of the preceding claims,wherein the cellulose material comprises at least 90% cellulose fibres by dry weight.

12. A method according to any of the preceding claims, wherein the cellulose material comprises cellulose fibres and at least one additive.

13. A cellulose product forming mould (3) for dry-forming a High Density Dry Moulded Fibre tube-shaped cellulose product (1 ) from a cellulose material (2), wherein the product forming mould (3) comprises a first mould part (4), a second mould part (5) and a third mould part (6), where the first mould part (4) comprises a cavity (8), where the second mould part (5) comprises a shaft (9), and where the third mould part (6) comprises a tube-shaped pressing member (10), c h a r a c t e r i z e d i n that the shaft (9) of the second mould part (5) is configured to be arranged in the cavity (8) of the first mould part (4), thereby creating a tube-shaped forming space (11 ) between the first mould part (4) and the second mould part (5); that the tube-shaped pressing member (10) of the third mould part (6) is arranged around the shaft (9) of the second mould part (5), and that the forming mould (3) is configured to press cellulose material (2) arranged in the tubeshaped forming space (11 ) with a pressing surface (17) of the tube-shaped pressing member (10) with a forming pressure to obtain the tube-shaped cellulose product (1 ).

14. A High Density Dry Moulded Fibre tube-shaped cellulose product (1 ) formed from a cellulose material (2), c h a r a c t e r i z e d i n that the tube-shaped cellulose product (1 ) has a density greater than 1 ,30 g / cm315. A tube-shaped cellulose product according to any of claim 14, wherein a wall thickness of the tube-shaped cellulose product (1 ) varies with at least16. A tube-shaped cellulose product according to claim 14 or 15, wherein the tube-shaped cellulose product (1 ) comprises a lower end portion(20), an upper end portion (21 ) and a side wall (22) having an outer wall surface (23) and an inner wall surface (24), where the outer wall surface (23) and / or the inner wall surface (24) is provided with at least one protruding element (25).

17. A tube-shaped cellulose product according to claim 16, wherein the lower end portion (20) and / or the upper end portion (21 ) is provided with at least one protruding element (25).

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