Method for producing a cellulose product and cellulose product
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PULPAC AB
- Filing Date
- 2024-12-18
- Publication Date
- 2026-07-14
Smart Images
Figure CN122396578A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a method for producing three-dimensionally molded cellulose products using cellulose materials, wherein a first segment of the cellulose product is pressed with a low molding pressure, and a second segment of the cellulose product is pressed with a higher molding pressure. In this method, three-dimensionally molded cellulose products with segments having different densities are provided, wherein the average density of the first segment is less than 1.30 g / cm³. 3 The average density of the second segment is greater than 1.30 g / cm³. 3 . Background Technology
[0002] Cellulose fibers are frequently used as raw materials for the production or manufacture of a wide variety of products. Products formed from cellulose fibers can be used in many different scenarios where sustainable products with substantially non-planar shapes are required. A substantially non-planar shape can refer to any suitable three-dimensional object shape. The range of products that can be produced from cellulose fibers is extremely broad, including, for example, disposable plates and cups, preform structures, and packaging materials. Packaging made from cellulose fibers can be used, for example, to package liquids, dry-process materials, and other types of articles, where the packaging can be formed into a three-dimensional shape or molded from a two-dimensional sheet into a three-dimensional shape. Such products are often laminated with different membranes to enable the product to withstand liquids, oils, heat, etc.
[0003] Cellulose fibers can be obtained by separating cellulose fibers from wood pulp, which is derived from, for example, wood or other plants. Wood pulp is a lignocellulosic cellulose cellulose material that can be prepared mechanically or chemically by separating cellulose fibers from wood or other plants. Wood pulp is obtained, for example, by grinding wood or trees in a mill (e.g., a disc mill), where the wood is ground into wood pulp. Wood pulp contains water, cellulose fibers, lignin, and hemicellulose. For some products, such as when strength is not a critical factor and / or when low cost is a priority, lignocellulosic materials, i.e., fibers without lignin removal, can be used.
[0004] Different processes exist for separating lignocellulose fibers. When preparing mechanical pulp, thermomechanical pulp, or chemi-thermomechanical pulp, the fibers are separated, but lignin is not removed from the cellulose fibers. In the chemi-pulping process, lignin and some hemicellulose are more or less completely removed from the pulp, yielding high-purity cellulose fibers, hereinafter referred to as pure cellulose fibers.
[0005] One material commonly used in cellulosic fiber products is wet-molded wood pulp. The wood pulp used for wet molding is typically obtained from recycled cardboard and newspaper, where the cellulosic fibers contain lignin. This reduces costs. The advantage of wet-molded wood pulp lies in its status as a sustainable packaging material, as it is made from biomaterials and can often be recycled or composted after use. Therefore, the popularity of wet-molded wood pulp in various applications is rapidly growing. Wet-molded wood pulp articles are typically formed by immersing a suction mold into a liquid or semi-liquid wood pulp suspension or slurry, and during suction, a wood pulp body is formed by fiber deposition, conforming to the shape of the desired product. The suction mold is then removed from the suspension, and suction is typically continued to compact the deposited fibers while draining residual liquid. For all wet molding technologies, a drying process is required for the wet-molded product, which is a very time-consuming and energy-intensive step in production, resulting in high costs. Furthermore, this method requires a large amount of water. The demands on the aesthetic, chemical, and mechanical properties of the product are increasing, and the mechanical strength, flexibility, and chemical properties are limited due to the properties of wet-molded cellulose products. In wet molding processes, it is also difficult to control the mechanical properties of the product with high precision.
[0006] Another known method for producing products from cellulose materials involves pressing loose cellulose fibers in a dry state, known as dry molding fiber (DMF). These products can be manufactured cost-effectively without using water as a carrier for the cellulose fibers and reduce energy requirements. Such products can be used to replace single-use plastic products, but there are some limitations in terms of strength and the feasibility of significantly varying product thickness.
[0007] In the DMF process, cellulose fibers are molded in conventional compression molds at molding pressures of 4-20 MPa. In this type of molding, the cellulose fibers arranged within the cellulose preform structure are slightly stretched when forming a non-flat shape. Because the cellulose preform structure cannot float or stretch, it is difficult to produce dry-molded cellulose products with thickness variations that vary with the cellulose product. The production cost of DMF products is similar to that of single-use plastic products.
[0008] Therefore, there is a need for improved sustainable cellulose products, which have improved mechanical and chemical properties, can be manufactured with high precision, and are produced at low and reasonable costs. Summary of the Invention
[0009] The object of this disclosure is to provide a method for producing three-dimensional cellulose products, wherein the aforementioned problems are avoided. This object is achieved at least in part by the features of the independent claims. The dependent claims contain further definitions of the method for producing three-dimensional cellulose products. Another object of this disclosure is to provide three-dimensionally shaped cellulose products.
[0010] This disclosure relates to a method for producing cellulose products from a cellulose material containing between 6% and 20% water. The method includes the steps of: arranging the cellulose material in a molding die; heating the molding die to a molding temperature in the range of 100°C to 300°C; and molding the heated cellulose material in the molding die using molding pressure to obtain a cellulose product from the cellulose material. A first segment of the cellulose product is molded under a first molding pressure between 4 and 20 MPa, and a second segment of the cellulose product is molded under a second molding pressure of at least 100 MPa. The cellulose material is formed into a three-dimensional cellulose product, and the density of the first segment is less than 1.30 g / cm³. 3 Furthermore, the density of the second segment is greater than 1.30 g / cm³. 3 .
[0011] The advantage of these features is that this method provides an efficient manufacturing process for cellulose products with improved mechanical and chemical properties, wherein the cellulose product comprises a first segment consisting of conventional dry molding fiber (DMF) material and a second segment consisting of high-density dry molding fiber (HD-DMF) material. The advantage of this method is that it provides cellulose products with different densities and strength properties. The conventional DMF segment is molded at a molding pressure in the range of 4-20 MPa, while the HD-DMF segment is molded at a molding pressure greater than 100 MPa. The density of the first segment is less than 1.30 g / cm³. 3 Furthermore, the density of the second segment is greater than 1.30 g / cm³. 3 Cellulose products may include several second stages.
[0012] One advantage of this type of product is that only one or more sections requiring higher strength are configured with a higher density. In one example, the cutlery cutter has a high-density cutting edge, while the handle and the rest of the blade have a density of less than 1.30 g / cm³. 3 The conventional DMF. Using high molding pressure only on segments of the cellulose product to mold it to a higher density reduces costs, as higher pressure is more expensive. To produce, for example, knives (where the entire knife is molded at high molding pressures exceeding 100 MPa), a larger press is required, or the number of knives that can be molded simultaneously is reduced. By using high molding pressure only on segments of the knife and low molding pressure on the rest, more knives can be molded simultaneously with a given pressure. In this way, dry-molded cellulose knives can be obtained at costs comparable to disposable plastic knives.
[0013] During the molding of cellulose materials, the cellulose fibers in the second stage will exhibit a pseudo-liquid state during the pressing action at molding pressures greater than 100 MPa, meaning that the cellulose fibers will exhibit liquid-like properties during the molding process. During the molding action of the second stage with high molding pressures (where the second molding pressure exceeds 100 MPa), the forces acting on the cellulose fibers as the three-dimensional product is molded will provide not only compressive forces but also shear forces, as the cellulose fibers will undergo a certain degree of displacement in the lateral direction. In one example, depending on the cellulose product and the cellulose material, the second molding pressure is higher than 150 MPa and can be higher than 200 MPa or even higher. The use of various additives in the cellulose material may also affect the optimal second molding pressure.
[0014] While a higher second molding pressure will result in higher strength and density in the second segment of the cellulose product, the preferred second molding pressure is one that meets the required parameters for the second segment of the cellulose product without exceeding those parameters. Higher second molding pressure increases the cost of the cellulose product. For this reason, it is advantageous to apply higher molding pressure only to selected segments of the cellulose product where higher strength is required.
[0015] One such example is cutlery. When the cellulose product is a knife, the cutting edge can be molded to a higher density using higher molding pressure to provide a sharp and strong cutting edge, while the rest of the knife is molded using conventional, lower molding pressure. When the cellulose product is a fork, the tines or teeth can be molded to a higher density using higher molding pressure to provide sharp and pointed tines. Other cellulose products that can be configured with segments of different densities and therefore different strengths are, for example, trays, where a reinforcing pattern of high-density grooves can be applied to increase the tray's load-bearing capacity. In this way, the raw material for the tray can have a lighter weight. Another advantage of using segments with higher density is that, for example, in trays or other products, corners should be sharp. By molding the edges with high molding pressure, the cellulose material in the corner areas will exhibit liquid-like properties, which will allow the cellulose material to fill the corner areas. It has been shown that molding pressures exceeding approximately 100 MPa will begin to impart pseudo-liquid properties to the cellulose material.
[0016] One advantage of higher molding pressures, when cellulose fibers exhibit pseudo-liquid properties, is the ability to obtain complex shapes that are difficult to achieve with conventional pressing of dry-molded fibers, using molding pressures such as 4-20 MPa. In conventional DMF molding, cellulose fibers arranged in the cellulose preform structure are slightly stretched when forming non-planar shapes. Because the cellulose preform structure does not float, it is difficult to produce dry-molded cellulose products with thickness variations that vary with the cellulose product. Using the method of this invention, cellulose products with one or more segments of more complex shapes can be produced, where the strength and density of the cellulose product vary. This method can also be used, for example, for the neck of a dry-molded cellulose fiber bottle, where the neck has external threads and a smooth inner surface, and the neck is molded at a molding pressure exceeding 100 MPa. To save costs, the rest of the bottle can be produced with conventional molding pressures of 4-20 MPa.
[0017] The cellulose product is formed in a molding die, which includes a first punch and a second die. In one example, the molding die components are non-flexible, preferably made of steel, and can be heated to a desired molding temperature. In one example, the molding die is heated using an integrated heating element (preferably an electric heating element), but liquid heating is also possible. One of the molding die components may also comprise a solid flexible material, such as silicone or rubber. The mold component intended for molding a first segment of the cellulose product can be made of such a flexible material. The solid flexible material can be used to homogenize the molding pressure acting on the cellulose material during the pressing action. The mold component for molding a second segment of the cellulose product is made of a rigid and non-flexible material, such as steel or another rigid material.
[0018] During the molding of three-dimensional cellulose products, different forces act on the molded cellulose material. When pressing a flat cellulose product, all molding pressure acting on the cellulose material is in the same direction as the molding pressure, i.e., perpendicular to the mold surface. When pressing a three-dimensional cellulose product, some forces will not be parallel to the molding pressure direction, but perpendicular to the mold surface. Since the cellulose material does not float, it will be stretched and displaced to some extent to correspond to the three-dimensional shape of the mold. For low molding pressures of 4-20 MPa, this small displacement of the cellulose material can be ignored. At higher molding pressures exceeding 100 MPa, this small displacement of the cellulose material will induce some shear forces. These shear forces, combined with the high molding pressure, cannot be ignored, but will simultaneously cause some localized pseudo-liquid regions where the cellulose material will exhibit liquid-like properties.
[0019] In the example shown, the cellulose material is a dry-formed cellulose preform structure comprising loose cellulose fibers. Therefore, the cellulose material is a dry-formed cellulose preform structure formed in a dry-forming process, wherein the cellulose fibers are carried by air as a carrier medium and formed into a dry-formed cellulose preform structure. In the specification, the dry-formed cellulose preform structure is sometimes referred to as an air-laid cellulose preform structure. For air-laid / dry-formed cellulose preform structures, the weight of the cellulose preform structure used for conventional DMF products is typically in the range of 400-800 GSM (grams per square meter). Using this material, a density exceeding 1.30 g / cm³ can be obtained. 3 The high-strength second product segment of the cellulose HD-DMF product, wherein the first segment of the cellulose product is set with less than 1.30 g / cm³. 3 And may be below 1.10 g / cm³ 3 The density.
[0020] In one example, the cellulose material consists of pure cellulose fibers without any additives. Pure cellulose fibers refer to cellulose fibers produced from chemical wood pulp, in which most of the lignin and hemicellulose are removed. The cellulose material may also include additives, which are used to reduce the liquid and / or gas permeability of the cellulose product and increase resistance to, for example, hot and cold liquids, greases, oils, etc. Such additives may also be applied to the surface of the cellulose product after molding. In one example, the cellulose material comprises at least 95% cellulose fibers by dry weight and up to 5% suitable additives. The cellulose material may contain up to 99% cellulose fibers by dry weight. The purpose of the additives is to increase resistance to liquids, greases, oxygen, etc. Additives are not binders. Binders are required for product preparation. Additives are materials that improve the product but are not essential for its production. Binders reduce the formation of hydrogen bonds between cellulose fibers in the product.
[0021] The cellulose material may include a first region and a second region. The first region corresponds to a first product segment of the cellulose product and has a weight between 400 and 800 GSM. The second region corresponds to a second product segment of the cellulose product and has a weight greater than that of the first region. The weight of the second region may be, for example, 1000 GSM or greater.
[0022] It has a density of less than 1.30 g / cm³ 3 The first segment and density exceed 1.30 g / cm³ 3An example of a cellulose product with one or more second segments is cutlery. When the cellulose product is a knife, the cutting edge can be molded to a higher density using higher molding pressure to provide a sharp and strong cutting edge, while the rest of the knife is molded using conventional, lower molding pressure. When the cellulose product is a fork, the tines or teeth can be molded to a higher density using higher molding pressure to provide sharp and pointed tines. Other cellulose products that can be configured with segments of different densities and therefore different strengths include, for example, trays, where a reinforcing pattern of high-density grooves can be applied to increase the tray's load-bearing capacity. Another advantage of using segments with higher density is that, for example, in trays or other products, corners should be sharp. By molding the edges with high molding pressure, the cellulose material in the corner areas will exhibit liquid-like properties, which will allow the cellulose material to fill the corner areas. It has been shown that pseudo-liquid properties will begin to be imparted to the cellulose material when the molding pressure exceeds approximately 100 MPa.
[0023] Another suitable cellulose HD-DMF product is the neck of a dry-molded cellulose fiber bottle, which features external threads and a smooth inner surface. To save costs, the rest of the bottle can be produced using conventional molding pressures of 4-20 MPa.
[0024] Cellulose HD-DMF products are formed in a molding die during a cycle time of 0.1 to 10 seconds (preferably less than 5.0 seconds). A suitable holding time for the product in the molding die is less than 1 second, and can be 0.3-0.7 seconds. Holding time, along with molding temperature and molding pressure, are important parameters in the molding of cellulose products.
[0025] Regarding cellulose materials, it should be noted that all cellulose-based materials mentioned in this application are derived from lignocellulosic biomass, i.e., dried plant matter. Lignocellulosic materials can be processed in various ways to produce chemical, semi-chemical, or mechanical pulp, as is known in the art. Chemical treatment of lignocellulosic biomass removes most of the lignin and hemicellulose, while mechanical treatment produces cellulose fibers with high lignin and hemicellulose content. Chemical pulp yields approximately 50%, and is therefore more expensive than mechanically treated lignocellulosic material with a yield of approximately 90%. Depending on the type of product and / or the type of design and / or the type of use, the DMF method described can use any type or combination of chemical, semi-chemical, or mechanical pulp. Therefore, cellulose materials can be in the form of pure cellulose (i.e., substantially free of lignin and hemicellulose) and / or lignocellulosic materials. In summary, pure cellulose is a chemically treated lignocellulosic material in which almost all of the lignin and hemicellulose are removed. One advantage of pure cellulose is its ability to form a large number of hydrogen bonds that bind the fibers together to form a strong and self-supporting three-dimensional product. Lignin and hemicellulose appear to form fewer hydrogen bonds than pure cellulose, making pure cellulose the preferred choice to reduce the need for additional materials. However, for certain types of products, lignin and hemicellulose may be used for cost reasons without compromising product quality (e.g., by using more fibrous material in the mold). Attached Figure Description
[0026] The present disclosure will now be described in more detail with reference to the accompanying drawings, in which...
[0027] Figure 1 The method for producing cellulose products with segments of different densities from a cellulose preform structure, according to the present disclosure, is illustrated schematically.
[0028] Figures 2a-2b The illustration schematically shows a molding die according to the present disclosure for producing cellulose products with different density segments from a cellulose preform structure.
[0029] Figure 3 Another example of a molding die according to this disclosure for producing cellulose products with different density segments from a cellulose preform structure is illustrated.
[0030] Figure 4 Another example of a molding die according to this disclosure for producing cellulose products with different density segments from a cellulose preform structure is illustrated.
[0031] Figure 5 The illustration schematically depicts cellulose products with different density segments produced from a cellulose preform structure according to the present disclosure.
[0032] Figure 6 The illustration schematically shows cellulose products with different density segments produced from cellulose preform structures according to the present disclosure, and...
[0033] Figure 7 The illustration schematically shows cellulose products with different density segments produced from cellulose preform structures according to the present disclosure. Detailed Implementation
[0034] The following description of various aspects of this disclosure is intended to illustrate, rather than limit, the disclosure, wherein like reference numerals denote like elements, and variations of the described aspects are not limited to the embodiments specifically shown, but may be applied to other variations of this disclosure.
[0035] In a specific embodiment, a method for producing a cellulose product from a cellulose material will be described, the cellulose product having a density of less than 1.30 g / cm³. 3 The first segment and density are higher than 1.30 g / cm³ 3 The second segment. This method is applicable to various DMF products, where segments with higher density and therefore higher strength (e.g., tensile strength) are advantageous. High-density segments are preferably relatively small to reduce the required high-cost overall molding pressure. Examples of such cellulose DMF products are, for example, cutlery such as knives and forks, coffee boxes, trays, snap-on lids, etc. In the example shown, a knife is used as an example of a cellulose DMF product.
[0036] In one example, the cellulose material used to form the cellulose DMF product is pure cellulose fiber without any additives. Pure cellulose fiber refers to cellulose fiber produced from chemical wood pulp, in which most of the lignin and hemicellulose are removed. The cellulose material may also include additives, which are used to reduce the permeability of the cellulose product and to increase resistance to substances such as hot and cold liquids, greases, oils, etc. In one example, the cellulose material comprises at least 95% cellulose fiber by dry weight and at most 5% additives by weight. The cellulose material may also contain some water, for example, 6% to 20% water by weight. In one example, the water content of the second segment of the cellulose preform is higher than that of the first segment. The higher water content in the second segment, combined with shear forces, will increase the flowability of the cellulose fibers.
[0037] Figure 1A method for producing cellulose DMF products 1 with segments of different densities using an air-laid cellulose preform structure 2 is schematically illustrated. When the cellulose preform structure is formed in an air-laid process, the cellulose fibers are carried by air as a carrier medium and formed into the cellulose preform structure. In the air-laid process, small amounts of water or other substances can be added to the cellulose material if desired to alter the properties of the cellulose product, but air is still used as the carrier medium in the forming process. The layers of the dry-formed cellulose preform structure can have a dryness primarily corresponding to the ambient humidity of the atmosphere surrounding the cellulose preform structure. Additional water can be added to the cellulose preform structure to achieve a water content of 20% by weight. Lower water content is possible, but this may be difficult to achieve due to the moisture in the ambient air. In the example shown, the cellulose preform structure 2 may include a first thin fiber layer and a second thin fiber layer arranged on each side of the cellulose preform structure 2. To produce the cellulose DMF product, the cellulose preform structure can be arranged as a layered continuous fiber web. Continuous fiber webs can be formed from these layers in a series of process steps, wherein the continuous fiber webs are fed into a molding die to be shaped into cellulose products.
[0038] In the method shown for manufacturing cellulose DMF products in a cellulose product molding apparatus 6, a cellulose preform structure 2 is dry-molded, arranged in a molding die 3, heated to the molding temperature, and pressed with molding pressure in the molding die 3. In the first step, the cellulose preform structure 2 is dry-molded in a dry molding unit including a mill 8, a molding box 9, molding wire 12, and a compaction unit 11. The cellulose preform structure 2 is molded into a three-dimensional cellulose product 1 by this method.
[0039] In mill 8, cellulose is dissociated into discrete cellulose fibers. The cellulose material used in mill 8 is preferably a high-purity cellulose material, such as fluff pulp, which contains a high content of cellulose fibers. As an example, the mill can be a conventional hammer mill. Standard raw fluff pulp can be used as the cellulose raw material and can be purchased, for example, in rolls 7 on the open market. Figure 1 In this process, the fluff pulp roll 7 is used as a raw material and is supplied to the mill.
[0040] Cellulose fibers are conventionally arranged on forming wire 12. Discrete cellulose fibers are extracted from the mill by a centrifugal fan and blown into a forming chamber 9 arranged above the forming wire 12. A vacuum chamber 10 may be arranged below the upper portion of the forming wire 12. The forming chamber 9 may include multiple fiber separating rollers arranged in the chamber housing to uniformly distribute the cellulose fibers onto the forming wire 12. The cellulose fibers are drawn onto the forming wire 12 by the vacuum in the vacuum chamber 10 to form a cellulose preform structure, which is then conveyed by the forming wire 12 to a compaction unit 11. The forming wire 12 can be conventionally arranged as an annular belt (e.g., made of a woven mesh structure) that moves continuously at a constant speed while forming the cellulose preform structure. The density of the cellulose preform structure can be selected to suit the cellulose product to be formed.
[0041] To form the cellulose preform structure 2, the cellulose fibers are preferably compacted or calendered in the compaction unit 11. In this way, the cellulose preform structure 2 is formed into a continuous cellulose preform structure 2. In one example, the dry forming of the cellulose preform structure 2 can be part of a continuous process, such as... Figure 1 As shown, the cellulose product is manufactured in the cellulose product molding equipment 6. Alternatively, the cellulose preform structure can be molded into discrete, independent parts corresponding to the cellulose product.
[0042] The cellulose product is formed in a molding die 3, which includes a first die component 4 and a second die component 5. In the example shown, the first die component is an upper punch component, and the second die component is a lower die component. The molding die components may be non-flexible, preferably made of steel, and can be heated to the desired molding temperature. In one example, the molding die is heated using an integrated heating element (preferably an electric heating element), but liquid heating is also possible.
[0043] One of the molding die components may also include a solid flexible material, such as silicone rubber. This material may be included in the die components intended for molding the first segment of a cellulose product. The solid flexible material can be used to uniform the molding pressure acting on the cellulose material component during the pressing action.
[0044] The cellulose preform structure 2 can be arranged into the molding die 3 in any suitable manner, and as an example, the cellulose preform structure 2 can be manually arranged into the molding die 3. Another alternative is to provide a buffer 13 for the cellulose preform structure 2, which transports the cellulose preform structure 2 to the molding die. The buffer can be, for example, a conveyor belt, an industrial robot, or any other suitable manufacturing equipment. Figure 1As shown, the cellulose preform structure can be supplied to the molding die 3 together with the molding wire 12, wherein when the molding wire 12 moves at a constant speed, the buffer intermittently supplies the cellulose preform structure to the molding die 3, and the cellulose product is formed in the molding die 3 in intermittent process steps.
[0045] As described above, cellulose product 1 is made from cellulose fibers, and may include at least 90% cellulose fibers by weight. Sizing agents or other suitable additives may be applied to the cellulose fibers to increase the hydrophobicity, mechanical strength, and / or other properties of the cellulose preform structure 2. For example, the cellulose product may contain 90-98% cellulose fibers by weight and 2-10% other substances by weight, such as starch, sizing agents, and / or other suitable additives and substances. To ensure that the cellulose product can be recycled after use, the added substances may be biodegradable or suitable for recycling.
[0046] To form a cellulose product, a cellulose preform structure 2 is arranged in a molding die 3, wherein the cellulose preform structure 2 is heated to a molding temperature in the range of 100°C to 300°C, and pressed in the molding die 3 with a molding pressure of at least 1 MPa. When pressed by the pressing unit 14, the heating of the cellulose preform structure 2 preferably occurs in the molding die 3.
[0047] When cellulose fibers are pressed at a molding pressure of at least 1 MPa and a molding temperature ranging from 100°C to 300°C, the fibers bond together, resulting in a cellulose product with good mechanical properties. Tests show that higher molding temperatures impart stronger adhesion between cellulose fibers when pressed at specific molding pressures. At molding temperatures above 100°C and molding pressures of at least 1 MPa, cellulose fibers bond firmly together via hydrogen bonds. Higher molding temperatures increase the fibril agglomeration, water resistance, Young's modulus, and mechanical properties of the final cellulose product. High molding pressure is important for fibril agglomeration in cellulose products. Cellulose fibers undergo thermal degradation at temperatures above 300°C, and therefore temperatures above 300°C should be avoided. Molding pressures and temperatures can be selected to suit the specific cellulose product to be produced.
[0048] In one example, the molding die includes a first mold area arranged to apply a molding pressure in the range of 4-20 MPa to the cellulose preform structure, thereby molding a first segment of the cellulose product. This molding pressure will provide an average density of less than 1.30 g / cm³. 3 And in one example at 1.00 g / cm 3 and 1.10 g / cm 3The regular DMF segments are located between the molding die and the cellulose preform. The first mold region is preferably a larger portion of the molding die. The molding die further includes at least one second mold region arranged to apply a molding pressure exceeding 100 MPa to the cellulose preform structure, such that the average density of the second segment of the cellulose product is higher than 1.30 g / cm³. 3 Or higher. Between the first mold region and the second mold region, there may be an intermediate mold region bridging the first mold region and the second mold region. The intermediate mold region forms a transition section of the cellulose product, and its density is between that of the first product section and the second product section.
[0049] The first mold component 4 includes a first mold surface 18, a second mold surface 19, and a fifth mold surface 22. The second mold component 5 includes a third mold surface 20, a fourth mold surface 21, and a sixth mold surface 23. The first mold surface 18 and the third mold surface 20 are arranged to face each other, the second mold surface 19 and the fourth mold surface 21 are arranged to face each other, and the fifth mold surface 22 and the sixth mold surface 23 are arranged to face each other.
[0050] A first mold region 15 is formed between a first mold surface 17 of a first mold component and a third mold surface 19 of a second mold component. This first mold region will form a first product segment 24 of the cellulose product and corresponds to a conventional molding die for conventional DMF products. The distance between the first and third mold surfaces in the first mold region corresponds to the thickness of the cellulose product and, depending on the actual cellulose product, can be, for example, between 0.6 and 2.0 mm. The first product segment will thus achieve a content below 1.30 g / cm³. 3 The average density, and in one example, at 1.00 g / cm³. 3 and 1.10 g / cm 3 between.
[0051] The second mold region 16 is formed between the second mold surface 18 of the first mold component and the fourth mold surface 20 of the second mold component, and is configured to apply a molding pressure exceeding 100 MPa to the cellulose preform structure, such that the second product segment 25 of the formed cellulose product achieves a density higher than 1.30 g / cm³. 3 Or a higher average density. In one example, the distance between the second mold surface and the fourth mold surface in the second mold region can be between 0.1 and 0.6 mm, depending on the actual cellulose product.
[0052] An intermediate mold region 17 is formed between the fifth mold surface 22 of the first mold component and the sixth mold surface 23 of the second mold component, and is configured to apply a molding pressure between 20 and 100 MPa to the cellulose preform structure. This provides a transition section 26 with a density between the first and second product sections. Depending on the cellulose product, the transition section may be relatively small or absent altogether.
[0053] The thicknesses of the first product segment, second product segment, and transition segment of the cellulose product are defined in the first mold region, the second mold region, and the intermediate mold region, and in the distance between the first mold component and the second mold component. In one example, the first mold component is flat, such that the first mold surface, the second mold surface, and the fifth mold surface are arranged in the same plane. In this example, all surface variations are arranged on the second mold component.
[0054] Figure 2a An example of a molding die 3 including a first mold component 4 and a second mold component 5 in an open state is shown, and Figure 2b A molding die in a closed state is shown. The molding die shown includes a plurality of second mold regions 16 arranged to provide a plurality of second mold segments in a cellulose product. The second mold regions 16 are arranged between first mold regions 15. In this example, the cellulose product may be, for example, a tray, and the second mold segments may provide reinforcing grooves in the bottom region of the tray. The second mold components include a plurality of protruding fourth mold surfaces 21 arranged between third mold surfaces 20 of the second mold components 5. The first mold component 4 includes corresponding first mold surfaces 18 and second mold surfaces 19, which are arranged in the same plane.
[0055] When a cellulose product is formed in a molding die, the cellulose preform structure is positioned within the die, and the die is closed. When the die is closed, molding pressure is applied to the cellulose preform structure. In the first die region 15, the molding pressure will be in the range of 4-20 MPa, while in the second die region, the molding pressure will be higher than 100 MPa. The obtained molding pressure depends on the weight (GSM, grams per square meter) of the cellulose preform structure, the geometry of the molding tool, and the pressure of the pressing unit. By adjusting these parameters, a cellulose product with one or more second die sections having a weight higher than 1.30 g / cm³ can be obtained. 3 Or a higher average density.
[0056] Figure 3A schematic example of a molding tool is shown, which has a second mold section 16 arranged at a location on a molding die. A larger portion of the molding die has a first mold region 15 arranged between a first mold surface 18 of the first mold section and a third mold surface 20 of the second mold section. This could be used, for example, as a blade for a cellulose cutting tool having regular dry-molded fiber properties, such as 1.00-1.10 g / cm³. 3 The average density is between 0.6 and 1.5 mm, and the thickness is between 0.6 and 1.5 mm. A second mold section 16 is disposed at one end of the molding tool and can be used, for example, as a cutting edge for a cellulose tool, wherein the second mold section 16 is disposed between the second mold surface 19 of the first mold component and the fourth mold surface 21 of the second mold component. An intermediate mold section is disposed between the fifth mold surface 22 of the first mold component and the sixth mold surface 23 of the second mold component. In the example shown, the second mold surface 19 and the fifth mold surface 22 are disposed in the same inclined plane. In the second mold section, a molding pressure exceeding 100 MPa is applied to the cellulose preform structure, and in the intermediate mold section, a molding pressure gradually decreasing from 100 MPa to the molding pressure of the first mold section is applied.
[0057] Figure 4 Another schematic example of a molding tool is shown, which has a second mold section 16 arranged at a location on a molding die. A larger portion of the molding die has a first mold region 15 arranged between a first mold surface 18 of the first mold section and a third mold surface 20 of the second mold section. This could be used, for example, as a blade for a cellulose cutting tool having regular dry-molded fiber properties, such as 1.00-1.10 g / cm³. 3 The average density is between 0.6 and 1.5 mm, and the thickness is between 0.6 and 1.5 mm. A second mold section 16 is disposed at one end of the molding tool and can be used, for example, as the cutting edge of a cellulose tool, wherein the second mold section 16 is disposed between the second mold surface 19 of the first mold component and the fourth mold surface 21 of the second mold component. In this example, the distance between the second and fourth mold surfaces is equal throughout the second mold section. An intermediate mold section is disposed between the fifth mold surface 22 of the first mold component and the sixth mold surface 23 of the second mold component. In the second mold section, a molding pressure exceeding 100 MPa is applied to the cellulose preform structure, and in the intermediate mold section, a molding pressure gradually decreasing from 100 MPa to the molding pressure of the first mold section is applied.
[0058] In another example, the cellulose preform structure can be configured with regions of different weights, wherein the second region corresponding to the second product segment 25 of the cellulose product has a higher cellulose preform structure weight. The first region corresponding to the first product segment 24 can, for example, have a weight of 500 GSM, and the second region corresponding to the second product segment can have a weight of 1500 GSM. In this way, an average density of less than 1.30 g / cm³ can be obtained. 3 The first product segment has an average density higher than 1.30 g / cm³. 3 Or higher-grade cellulose products in the second product segment.
[0059] The distance between the molding surfaces of the mold components and / or the weight of the cellulose preform structure can be selected to obtain the desired cellulose product.
[0060] According to this disclosure, when the cellulose product is molded, the cellulose preform structure is further heated to a molding temperature in the range of 100°C to 300°C. Preferably, the molding die is heated to the molding temperature using an integrated heating element. The cellulose preform structure is pressed with molding pressure in the heated molding die to form the cellulose product.
[0061] The molding pressure in the first mold region is preferably between 4 and 20 MPa, resulting in a first product segment similar to a conventional DMF product. The molding pressure in the second region is at least 100 MPa or higher, resulting in a second product segment similar to an HD-DMF product. Cellulose products are formed by heating and pressing a cellulose preform structure in a molding die, wherein during molding, the cellulose preform structure is shaped into a three-dimensional fiber composite structure having a first low-density segment and a second high-density segment.
[0062] The second product segment will have higher tensile strength than the first product segment and, in one example, will be used to provide the cutting edge of the tool. Due to the higher strength, the cutting edge can be made thin and sharp, which will further improve the cutting performance of the tool. A transition segment will exist between the first and second product segments, where the density gradually increases from the first product segment to the second product segment. In one example, the tool length is approximately 150 mm, and the blade width is approximately 20 mm. The width of the second product segment can, for example, be between 1 and 5 mm, while the width of the transition segment is several millimeters.
[0063] When cellulose fibers are compressed, they bond together in a certain way, resulting in a cellulose product with good mechanical properties. Tests show that higher molding temperatures impart stronger bonds between cellulose fibers when compressed under specific molding pressures. At molding temperatures above 100°C and molding pressures of 4-20 MPa, cellulose fibers bond firmly together through hydrogen bonds. Cellulose fibers undergo thermal degradation at temperatures above 300°C, therefore temperatures above 300°C should be avoided.
[0064] When the molding temperature exceeds 100°C and the molding pressure exceeds 100 MPa, cellulose fibers exhibit liquid-like properties. During the molding process, the cellulose fibers can flow to a certain extent, resulting in high-density segments. The molding pressure and temperature can be selected to suit the specific cellulose product to be produced.
[0065] Tests show that when molding the first product segment with conventional DMF properties, the molding pressure level is in the range of 4-20 MPa, and the suitable temperature level is in the range of 100°C to 300°C. However, a temperature level in the range of 140°C to 200°C is usually sufficient to achieve DMF cellulose products with the desired properties. Tests further show that when molding the second product segment with HD-DMF properties, a molding pressure exceeding 100 MPa is required at the same temperature level. For some products, even higher molding pressures (up to 200 MPa or higher) may be preferred.
[0066] exist Figures 5 to 7 An example of cellulose product 1 is shown in the figure, wherein Figure 5 The cutting tool is shown. Figure 6 A fork was shown, and Figure 7 A coffee capsule is shown. In the example shown, the cellulose product includes a first thin cellulose fiber layer, a dry-formed cellulose fiber layer, and a second thin cellulose fiber layer. One or both thin cellulose fiber layers may contain additives to increase resistance to liquids, greases, oils, etc. Depending on the layout of the production system, only one thin cellulose fiber layer may be used, or no thin cellulose fiber layer may be used at all.
[0067] like Figure 5As shown, the cutting tool 27 is provided with a tool handle 28 and a blade 29, wherein the blade includes a cutting edge 30, which can be straight or serrated. A first product section 24 includes a portion of the handle and the blade, and a second product section 25 includes the cutting edge. A thin transition section 26 is provided between the first product section 24 and the second product section 25, wherein the density gradually changes from a lower density to a higher density. The handle and the blade are preferably provided with a non-flat shape to increase the strength of the first product section. The thickness of the cutting edge is the same as the blade at the transition section and is thinner at the outer edge of the blade, wherein the thickness of the cutting edge can be as thin as 0.1 mm.
[0068] like Figure 6 As shown, the fork 31 is provided with a fork handle 32 and a fork head 33, wherein the head includes a plurality of tines 34 extending from the head. The handle and head are contained in a first product section, having a low density and similar to conventional DMF products. The tines, or at least the outer ends of the tines, are contained in a second product section of the fork. The tines are thin and pointed, and have a density exceeding at least 1.30 g / cm³. 3 The high density results in sharp and strong fork teeth. The fork teeth may also include a transition section that connects the outer end of the fork teeth to the fork head.
[0069] Figure 7 An example is shown where the cellulose product is a coffee pod 35, which includes a bottom portion 36, a sidewall portion 37, and an edge portion 38. The bottom portion is provided with one or more grooves 39. The sidewall portion, a portion of the bottom portion, and the edge portion constitute a first product segment 24, and the grooves in the bottom portion constitute a second product segment 25. The grooves are thinner than a conventional bottom portion, and therefore the molding pressure applied to the molding die at the grooves will be higher, exceeding 100 MPa. The density of the grooves will therefore be higher than the density of the rest of the coffee pod. The thinner grooves can, for example, be used to form thinner segments for use when penetrating the bottom wall of the coffee pod.
[0070] Another suitable cellulose product with a different density segment is a food tray (not shown) having a bottom portion and sidewalls. The bottom portion has grooves formed in a predetermined pattern, applied at least over the bottom portion of the food tray. This pattern can be, for example, a cross pattern or may include parallel grooves. The grooves are formed with protrusions, for example, on a second lower mold component, where the protrusions form a second mold segment, and the remainder of the second mold component forms a first mold region, such that a higher molding pressure is applied to the grooves in the second mold region. Therefore, the density of the grooves will be higher than that of the rest of the bottom portion and will exceed 1.30 g / cm³. 3The grooves help strengthen the bottom area of the tray, allowing for the use of lighter airflow-laid cellulose preform structures to shape the food tray. By utilizing the reinforcing grooves, for example, the weight of the cellulose preform structure can be reduced from 450 GSM to 400 GSM to obtain a food tray with the same strength.
[0071] According to the required parameters of cellulose product 1, the molding pressure in the second region of the molding die is at least 100 MPa, and can be as high as 200 MPa or higher. During the molding of the cellulose product, the cellulose material in the second segment of the cellulose product is exposed to high molding pressure. During the molding of the cellulose HD-DMF segment, due to the high molding pressure and the water contained in the cellulose material, the cellulose fibers will exhibit a pseudo-liquid state, causing the cellulose fibers to shift to a certain extent in the molding die, completely filling the second molding die region, as the cellulose fibers will locally exhibit liquid properties. This pseudo-liquid behavior will allow the cellulose fibers to uniformly fill the second molding die region.
[0072] The high molding pressure, water content, and the fact that cellulose fibers must undergo a certain degree of displacement in the second stage cause the cellulose fibers to exhibit a pseudo-liquid state. The high pressure and shear forces acting on the cellulose fibers create the pseudo-liquid state. After a specific holding time, the cellulose product is ready and can be removed from the molding die.
[0073] It should be understood that the foregoing description is merely exemplary in nature and is not intended to limit this disclosure, its application, or use. Although specific examples have been described in the specification and illustrated in the drawings, those skilled in the art will understand that various changes can be made and elements can be replaced with equivalents without departing from the scope of protection defined in the claims of this disclosure. Furthermore, modifications can be made to adapt particular situations or materials to the teachings of this disclosure without departing from the essential scope of this disclosure. Therefore, this disclosure is not limited to the specific examples shown in the drawings and described in the specification as the best mode for implementing the teachings of this disclosure, but the scope of this disclosure will include any embodiments falling within the foregoing description and appended claims. Reference numerals used in the claims should not be considered as limiting the scope of the claims, and their sole purpose is to facilitate understanding of the claims.
[0074] Reference tag list
[0075] 1: Cellulose products
[0076] 2: Cellulose preform structure
[0077] 3: Molding mold
[0078] 4: First mold component
[0079] 5: Second mold component
[0080] 6: Molding equipment
[0081] 7: Wood pulp rolls
[0082] 8: Grinding mill
[0083] 9: Molding box
[0084] 10: Vacuum chamber
[0085] 11: Application Roller
[0086] 12: Molded wire
[0087] 13: Buffer
[0088] 14: Suppression Unit
[0089] 15: First mold area
[0090] 16: Second mold area
[0091] 17: Intermediate mold area
[0092] 18: Surface of the first mold
[0093] 19: Second mold surface
[0094] 20: Surface of the third mold
[0095] 21: Surface of the fourth mold
[0096] 22: Surface of the fifth mold
[0097] 23: Surface of the sixth mold
[0098] 24: First Product Section
[0099] 25: Second Product Section
[0100] 26: Transition Section
[0101] 27: Knives
[0102] 28: Knife Handle
[0103] 29: Blade
[0104] 30: Cutting blade
[0105] 31: Fork
[0106] 32: Fork handle
[0107] 33: Fork head
[0108] 34: Fork tooth
[0109] 35: Coffee pouch
[0110] 36: Bottom section
[0111] 37: Side wall portion
[0112] 38: Edge section
[0113] 39: Groove
Claims
1. A method for producing three-dimensional dry-molded fiber cellulose products (1) from cellulose material (2), wherein, The method includes the following steps: The cellulose material (2) is arranged in the molding die (3); The molding die (3) is heated to a molding temperature in the range of 100°C to 300°C; and The cellulose material (2) is molded in a heated molding die (3) under molding pressure to obtain the cellulose product (1), wherein a first product segment (24) of the cellulose product (1) is molded under a first molding pressure between 4 and 20 MPa, and wherein a second product segment (25) of the cellulose product (1) is molded under a second molding pressure of at least 100 MPa, wherein the cellulose material (2) is formed into a three-dimensional cellulose product (1), and wherein the average density of the first product segment (24) is less than 1.30 g / cm³. 3 Furthermore, the average density of the second product segment (25) is greater than 1.30 g / cm³. 3 .
2. The method according to claim 1, in, The second molding pressure is at least 150 MPa.
3. The method according to claim 1, in, The second molding pressure is at least 200 MPa.
4. The method according to any one of the preceding claims, in, The cellulose material is a dry-formed cellulose preform structure (2) formed in a dry forming process, wherein the cellulose fibers are carried by air as a carrier medium and formed into a dry-formed cellulose preform structure (2).
5. The method according to any one of the preceding claims, in, The cellulose material includes a first region and a second region. The first region corresponds to a first product segment (24) of the cellulose product (1) and the weight of the first region is between 400-800 GSM. The second region corresponds to a second product segment (25) of the cellulose product (1) and the weight of the second region is higher than that of the first region.
6. The method according to any one of claims 1 to 5, wherein, The molding die (3) includes a first mold component (4) and a second mold component (5), wherein the molding die (3) is provided with a first mold area (15) and a second mold area (16), the first mold area being arranged to mold a first product segment (24) of the cellulose product (1), and the second mold area being arranged to mold a second product segment (25) of the cellulose product (1).
7. The method according to any one of the preceding claims, in, The cellulose material comprises at least 95% cellulose fibers on a dry weight basis.
8. The method according to any one of the preceding claims, in, The cellulose material consists essentially of only cellulose fibers.
9. A three-dimensional cellulose product (1) formed from cellulose material (2), characterized in that, The cellulose product (1) includes a first product segment (24) and a second product segment (25), wherein the density of the first product segment is less than 1.30 g / cm³. 3 The density of this second product segment is greater than 1.30 g / cm³. 3 .
10. The product according to claim 9, wherein, The second product section (25) is arranged at the side edge of the cellulose product (1).
11. The product according to claim 9 or 10, wherein, The second product segment (25) is thinner than the first product segment (24).
12. The product according to any one of claims 9 to 11, wherein, The first product section (24) of the cellulose product (1) is molded at a molding pressure between 4 and 20 MPa, and the second product section (25) of the cellulose product (1) is molded at a molding pressure exceeding 100 MPa.
13. The product according to any one of claims 9 to 12, wherein, The cellulose material is a dry-formed cellulose preform structure.