A method and a machine for producing a thermoformed workpiece in thick paper

Abstract

The present invention provides a method for preparing thermoformed 3D workpieces from thick paper, comprising the following steps: feeding thick paper into a processing machine; die-cutting the paper to form a planar unfolded part of the 3D workpiece to be formed; applying a coating material to the paper or the planar unfolded part; placing the planar unfolded part into a heated mold; drawing the planar unfolded part deep into the mold using a punch; and removing the thermoformed 3D workpiece from the mold. In some embodiments, the paper is fed in the form of a single sheet. In alternative embodiments, the paper is fed in the form of a roll. In the embodiments described herein, the paper used is coated paper. The coating material (Q) is a sol, i.e., a viscous solution comprising a silicon compound, which initiates a condensation reaction during a stage after deposition onto the paper to form a three-dimensional lattice with silicon-oxygen bonds, wherein, depending on the exact composition of the initial sol, some silicon-oxygen bonds may be replaced by bonds between silicon and other substances. Preferably, the other substances are alkyl groups. The mold is heated to between 100°C and 250°C, preferably between 150°C and 200°C, to transform the coating material (Q) into a glassy layer. In the deep drawing process, a first forming step and a second de-wrinkling step are provided: in the first forming step, the first punch has a larger gap relative to the die forming the mold to prevent the paper from tearing; in the second de-wrinkling step, the second punch has a smaller gap relative to the die and presses the workpiece against the die to remove all residual wrinkles in the paper.

Description

Technical Field

[0001] This invention relates to the technical field of thermoformed workpieces made of thick paper.

[0002] Specifically, the present invention relates to a method and machine for preparing containers, such as coffee capsules, cup lids, primary and secondary containers for cosmetics, sauce containers, fruit puree containers, cups and boxes, containers for secondary packaging, containers for non-food products, etc. Background Technology

[0003] Coffee capsules made from cellulose pulp are already available on the market. The process mainly involves three steps: - Pulping steps; - Molding steps; and - Drying step.

[0004] The pulping system first feeds water and paper into a hydrapulper at a 3:1 ratio and mixes for 40 minutes. The pulp is then automatically conveyed to the feed tank. A pulp pump transports the pulp to a beater for further mixing, and finally back into the feed tank, which then delivers the pulp to the forming machine.

[0005] The pulp molding machine uses a vacuum pump to draw pulp from a pulp pump into the molding die. Excess water is absorbed and stored in a discharge pump. After the pulp is drawn into the molding die, the product is formed.

[0006] The drying system is used to evaporate the moisture in the wet trays at high temperatures to obtain usable products.

[0007] Products made using this technology have some limitations: 1) A plastic or bioplastic film needs to be inserted inside the product to ensure: a. Liquid-resistant; b. Gas barrier properties; and c. Poor resistance to high and low temperatures.

[0008] 2) The product has extremely high permeability. When the product comes into contact with liquid, especially under pressure and heat, substances contained in the paper will leach out, which changes the sensory characteristics of the beverage to be prepared.

[0009] 3) The product cannot be colored. Summary of the Invention

[0010] The object of the present invention is achieved by the method as defined in claim 1 and the machine as defined in claim 10. The technology described herein can overcome all the defects of pulping processes and can guarantee all of the following properties in a single product (paper): resistance to hot and cold liquids, resistance to greases, barrier properties against water vapor and oxygen, and the ability to withstand high and low temperatures.

[0011] The present invention provides a method for preparing thermoformed 3D workpieces made of thick paper, comprising the following steps: feeding thick paper into a processing machine, die-cutting the paper to form a planar unfolded part of the 3D workpiece to be formed, applying a coating material to the paper or to the planar unfolded part, placing the planar unfolded part into a heated mold, using a punch to draw the planar unfolded part deep into the mold, and removing the thermoformed 3D workpiece from the mold.

[0012] In some embodiments, the paper is fed in the form of a single sheet. In alternative embodiments, the paper is fed in the form of a roll.

[0013] In the embodiments described herein, coated paper is used.

[0014] In several embodiments, the coating material is a sol, i.e., a viscous solution comprising a silicon compound. This silicon compound initiates a condensation reaction during a stage after deposition onto paper to form a three-dimensional lattice of silicon-oxygen bonds, some of which may be replaced by bonds between silicon and other substances, depending on the exact composition of the initial sol.

[0015] In some embodiments, the other substance is an alkyl group.

[0016] More specifically, the mold is heated to a temperature between 100°C and 250°C, preferably between 150°C and 200°C, so that the coating material is transformed into a glassy layer.

[0017] In some embodiments, a first forming step and a second de-crease step are provided in the deep drawing step. In the first forming step, the first punch has a large gap relative to the die forming the mold to prevent the paper from tearing. In the second de-crease step, the second punch has a smaller gap with the die, pressing the workpiece against the die to remove all residual wrinkles from the paper.

[0018] Preferably, the first punch is a movable punch composed of multiple components that intervene in the operation at different times.

[0019] This technical solution also provides a machine for preparing thermoformed 3D workpieces made of thick paper. The machine includes a station for performing the following operations: feeding thick paper, die-cutting the paper to form a planar unfolded part of the 3D workpiece to be formed, applying a coating material to the paper or to the planar unfolded part, forming the 3D workpiece using a heated mold, performing deep drawing using a punch and a die, and removing the thermoformed 3D workpiece from the mold.

[0020] In some embodiments, the paper is fed in the form of a single sheet. In other alternative embodiments, the paper is fed in the form of a roll.

[0021] Typically, the paper used in these machines is coated paper.

[0022] The coating material is a sol, i.e., a viscous solution comprising a silicon compound. This silicon compound undergoes a condensation reaction in subsequent stages after deposition onto the paper, forming a three-dimensional lattice composed of silicon-oxygen bonds; depending on the exact composition of the initial sol, some silicon-oxygen bonds may be replaced by bonds between silicon and other substances, preferably alkyl groups.

[0023] In some technical solutions, the coating station for coating materials is provided with a coating roller.

[0024] In addition, the mold is heated to between 100°C and 250°C, preferably between 150°C and 200°C, by a resistor, so that the coating material is transformed into a glassy layer.

[0025] In some embodiments, a first forming step and a second de-crease step are provided at the deep drawing station. In the first forming step, the first punch has a large clearance relative to the die forming the mold to prevent paper tearing. In the second de-crease step, the second punch has a smaller clearance with the die, pressing the workpiece against the die to remove all residual wrinkles from the paper.

[0026] Preferably, the first punch is a movable punch composed of multiple components that intervene in the operation at different times.

[0027] The technical solution also includes a thermoformed 3D workpiece made of thick paper prepared according to the above method, and a 3D workpiece made of thick paper using the machine.

[0028] Specifically, the mold is heated to polymerize the coating material and fix the paper product, while also giving the paper product mechanical strength and barrier properties against liquids and gases.

[0029] Furthermore, the paper forming process largely benefits from the paper being wetted by a coating material, allowing the wet fibers to move easily to fit the mold shape, thus creating 3D workpieces. Attached Figure Description

[0030] The following description will refer to the accompanying drawings, in which: - Figure 1 An example of a machine for producing thermoformed parts made of thick paper fed in sheet form is shown. - Figure 2 An example of a machine for preparing thermoformed parts made of thick paper fed in roll form is shown. Figure 3 shows an example of a coffee capsule and a planar unfolding component used to obtain the coffee capsule. Figure 4 shows some details of the planar unfolded part used to prepare thermoformed workpieces made of thick paper. - Figure 5 Some details of an example of a machine used to produce thermoformed parts from thick paper are shown. Figure 6 shows some details of the punch used to prepare the coffee capsule in Figure 3. Figure 7 shows another type of hemispherical coffee capsule and its associated planar unfolding component. - Figure 8 Details of the mold / punch assembly used to prepare the coffee capsules in Figure 7 are shown. Figure 9 shows an example of a fruit puree container and its associated planar unfolded components. Figure 10 shows details of the mold / punch assembly used to prepare the fruit puree container in Figure 9. Figure 11 shows an example of a lid for a takeaway cup, and Figure 12 shows details of the mold / punch assembly used to prepare the lid for the takeaway cup in Figure 11.

[0031] Where appropriate, components described in this specification are represented by conventional symbols in the accompanying drawings, which only show specific details that enable understanding of embodiments of the invention, so as not to make unnecessary disclosure of details that are obvious to those skilled in the art in conjunction with the description provided below. Detailed Implementation

[0032] The technical solution of the present invention will be described below with reference to the accompanying drawings.

[0033] The technique proposed in this paper can produce thick paper workpieces of arbitrary shape with a height-to-diameter ratio greater than 1 (e.g., a cup with a base diameter of 10mm and a height of 12mm) through deep drawing. The shape can be circular or polygonal.

[0034] As mentioned above, the following will provide some examples of applications of this technology: - Coffee capsules; - Cup lid; - Primary and secondary containers for cosmetics; - Sauce container; -Pure container; - Glasses and cups; - Containers for secondary packaging; - Containers for non-food products; -etc.

[0035] The base paper used in this technology can be either sheet or roll; the choice between sheet and roll mainly depends on the paper's basis weight. In fact, roll-form paper is designed for a maximum of 450g / m². 2 The weight. For weights exceeding 450 g / m³ 2 The paper can only be made from sheet paper. Clearly, the choice between sheet or roll paper is primarily determined by the shape of the workpiece and production capacity. Roll paper offers faster production speeds, but the investment is significantly higher, both in terms of machinery and molds. The proposed solution provides a method and machine for preparing thick paper workpieces.

[0036] The present invention provides a method for preparing thermoformed 3D workpieces made of thick paper, comprising the following steps: feeding thick paper into a processing machine, die-cutting the paper to form a planar unfolded part of the 3D workpiece to be formed, applying a coating material to the paper or to the planar unfolded part, placing the planar unfolded part into a heated mold, using a punch to draw the planar unfolded part deep into the mold, and removing the thermoformed 3D workpiece from the mold.

[0037] In the embodiments described herein, the paper used is coated paper or glossy paper.

[0038] Coated paper is a type of paper covered with a very thin white or micro-colored coating that gives it a glossy and smooth appearance.

[0039] The composition of the additional coating can use a variety of materials, including kaolin, calcium carbonate, bentonite and talc.

[0040] Depending on the properties that the coating is required to impart to the paper, the mineral filler is bonded by latex or a mixture of latex and adhesive. The primary purpose of the coating is to improve the printing quality of paper, but it can also be used to impart grease resistance or improve the water resistance of paper substrates.

[0041] Paper can be coated on only one side (this is called single-sided coating) or on both sides (this is called double-sided coating). Single-sided coating is used when printing is only required on one side of the paper; this is typically the case for food packaging paper. Double-sided coating is used when printing is required on both sides of the paper; this is typical for glossy magazine or book paper.

[0042] Single-sided or double-sided coated paper is used to give paper a smooth surface and can significantly reduce the porosity of the paper.

[0043] This is used to improve print quality or facilitate coating processes.

[0044] This solution can use various types of paper, but coated paper and double-sided coated paper are preferred because they can further highlight the properties of the coating material used (described in detail below), such as water resistance, oil resistance, and grease resistance. In fact, when using this type of coated paper or double-sided coated paper, the coating material remains on the surface, while in uncoated paper, the coating material penetrates into the fibers and becomes ineffective.

[0045] The paper that passed the tests and achieved the best results was a paper with a basis weight of 180 g / m². 2 Up to 1010g / m 2 Selected from the paper within the specified range.

[0046] For a weight of 180g / m 2 Up to 350g / m 2 The following types of paper from different manufacturers can be cited as examples within this scope: METSA BOARD: PRO FSB CUP, weight 265 g / m³ 2 , BURGO: SUN ICE 2SC, weight 350g / m³ 2 ,as well as IGGESUND: INVERCOTE GPX, weight 210 g / m³ 2 .

[0047] For a weight of 400 g / m 2 Up to 1010 g / m 2 Here are some examples of the paper: IGGESUND: INVERCOTE DUO, weight 700g / m³ 2 ,as well as BURGO: SUN ICE TRIO, weight 900g / m³ 2 .

[0048] The following section describes the technical solution proposed in this paper for a machine that feeds paper in sheet form. A machine M used to prepare thick paper workpieces C from a single sheet of paper F, such as Figure 1 As shown.

[0049] Paper sheet F is fed into die-cutting tool 10 via any known method or means, and die-cutting tool 10 cuts out individual unfolded parts S or planar blanks of the capsule C or container to be prepared. For example... Figure 1a As shown, multiple unfolded parts S can be prepared from each sheet of paper F. Based on the dimensions of the paper sheet F and the dimensions of the container C to be prepared, a corresponding arrangement design can be implemented to reduce waste.

[0050] Starting with the die-cut paper sheet F, each unfolded piece S is removed by a special fixture and positioned on the conveyor belt 14. Then, a coating material Q (which will be described in detail below - Qwarzo material) is applied to the unfolded piece S using a coating roller 20. The coating material Q is supplied to the coating roller 20 via a feed trough 25.

[0051] Preferably, the coating material Q is in a liquid or viscous state, so that it can be coated by the coating roller 20. The coating material Q can be applied to one or both sides. Depending on the type of product, both sides usually need to be treated.

[0052] After picking up the unfolded part S, collect the waste or scraps of paper F SF and pile them in area 16 for subsequent sorting of waste and recycling of paper. The processed planar unfolded part S+Q, i.e. the planar unfolded part that has been coated with coating material Q, is then inserted into the mold 30 by a robot arm 40 with a corresponding clamp 42, which is heated to at least 150 °C by a resistor. Once the planar unfolded part S is positioned in the mold 30, the individual planar unfolded part can be deep drawn using the punch 50 controlled by the press 55 to form a 3D product or container.

[0053] Each machine M can be equipped with a single die 30 and a single punch 50, or multiple dies 30i and multiple punches 50i to increase the production speed of container C. In the proposed scheme, the mold is heated to polymerize and fix the coating material Q onto the paper product, while giving the product mechanical strength and barrier properties against liquids and gases.

[0054] The forming of paper largely benefits from the paper being wetted by the coating material Q, as the fibers can easily move to fit the shape of the workpiece.

[0055] The unloading robot 60 removes the formed 3D product or container and positions it on the discharge conveyor belt 70.

[0056] The following describes the proposed solution, in which paper is fed into the machine via roll B. Figure 2 A machine M1 is shown for preparing thick paper workpieces C from continuous sheets of roll (paper roll) B.

[0057] The roll material B is unwound by the uncoiler 100 and treated with coating material Q (which will be described in further detail below – Qwarzo material) by the coating roller 110. The treated paper is then fed into the die 130 by the push feeder 120 and the pull feeder 140 located at the end of the die.

[0058] Once the paper, fed into the mold 130 by the roll B covered with the coating material Q, is die-cut, it is then deep-drawn by the transverse feed device (tra) 150 to form a 3D product or container C.

[0059] In this scheme, the mold 130 is also heated to at least 150 °C by a resistor to polymerize the coating material Q and fix the paper product, while giving the paper product mechanical resistance and barrier properties against liquids and gases.

[0060] A crucial part of this approach is the study of the planar unfolded part S of the die-cut product. Specifically, the planar unfolded part S is designed based on the characteristics of the 3D container to be prepared to prevent defects, tears, wrinkles, and other problems.

[0061] Therefore, preliminary studies of the planar unfolded part S, which will be used to produce the final product or container C, are crucial for preventing wrinkles and appearance defects and for ensuring the ability to manufacture complex shapes.

[0062] See Figure 3, which shows a method for preparing Figure 3a The unfolded part S of a known coffee capsule of the type shown. The unfolded part S is flower-shaped, with four petals P extending from the central part PC. The creases R visible on the four lobes P of the unfolded part S are indentations designed to facilitate folding the paper when needed. Therefore, creases R must be pressed into the correct positions on the paper to limit aesthetic and functional defects. The central part PC, however, does not have creases.

[0063] When manufacturing 3D products, one can start from pre-printed rolls B and / or sheets of paper F to prepare workpieces C with external printing or decoration as needed.

[0064] Referring to Figure 4, Figure 4 shows an unfolding component for a hemispherical container used in the cosmetics industry for face creams. Currently, these containers are made of plastic. As mentioned above, such as Figure 4b As shown, notches or thickness-reduced areas Z1 and Z2 can be provided on the die-cut components at the edge of the petals to prevent uneven thickness during overlap. This technique can be applied to all shapes requiring extremely high aesthetic properties. Specifically, the thickness of the two regions Z1 and Z2 decreases, so that when the two regions overlap, the resulting thickness is the same as the thickness of the rest of the container or capsule CC.

[0065] See Figure 5 The image shows a mold used to prepare the coffee capsules in Figure 3 using a machine with roll-fed material. In this case, the mold consists of two basic parts: - The first component A cuts and scores the paper; in this step, a cutting punch 200 is used to cut the paper, score it, and remove waste material SF. - The second part B of the mold performs the forming, trimming, and removal of the capsule.

[0066] In the aforementioned machines, paper sheets and rolls are fed by a drive system.

[0067] exist Figure 5 In the process, individual sheets of paper, as well as materials unwound from the roll, are fed from left to right to perform the processing required to produce the final workpiece.

[0068] The second part B of the mold is the most complex part, which consists of a punch 210 and a die 220.

[0069] The punch 210 is preferably movable. The punch 210 is composed of different segments (as shown in Figure 6), allowing it to open when it descends into the die 220. When the punch 210 is activated, the central portion 212 retracts (see...). Figure 6b Therefore, it is located in a more recessed position relative to the molding portion 214. In this state, the center portion 21 is located in a plane parallel to and further back than the plane including the molding portion 214. (See machining...) Figure 6b After that, the center part 212 of the punch 210 is aligned with the forming part 214, that is, the two are on the same plane.

[0070] In some processes, the forming punch 210 can also be fixed in place, i.e., made as a single piece, or kept in a fixed position. Figure 6b The state shown is used. This depends on the complexity of the article to be prepared.

[0071] The forming punch 210 has a gap much larger than the thickness of the paper, allowing the paper to be folded without tearing. This means that the size of the forming punch 210 is smaller than the size of the article to be produced (typically with a smaller diameter). See you again Figure 5 The die 220 is a rotating die with four or more cavities, which can perform different processes simultaneously for different unfolded parts S.

[0072] For example, refer to Figure 5 The rotary die 220 shown includes four molds SM1, SM2, SM3, and SM4, and four machining stations 1, 2, 3, and 4. The following steps are performed: Step 0 - Initialization: Initially, the four molds SM1, SM2, SM3 and SM4 are located at the corresponding four processing stations 1, 2, 3 and 4, respectively, and are all empty; Step 1 – Molding: The first unfolded part S1 is inserted into the first mold SM1 located at the first molding station 1, and cooperates with the movable punch or the fixed punch 210 to form a capsule or container C1. Step 2 – Pressing to Remove Wrinkles: After the rotating die 220 rotates one step, the first unfolded part S1, housed in the first die SM1, is fed into the second station 2. Simultaneously, the second unfolded part S2 is inserted into the fourth empty die SM4 at the first forming station 1 to form a capsule or container C2. The first unfolded part S1, now located at the second station 2 and housed in the first die SM1, is processed by a zero-clearance punch 230, driven by a cam, to press the formed capsule C1 and remove all wrinkles from the paper. While the zero-clearance punch 230 is processing, the cutting element 232 also trims the edges of the capsule C1 formed in step 1 of processing the first unfolded part S1. Step 3 – Removal: After the rotating mold 220 rotates one more step, the first unfolding part S1 in the first mold SM1 moves to the third station 3, and the second unfolding part S2 in the mold SM4 moves to the second station 2. At the second station, it is processed by the punch 230 with zero clearance. At the same time, the third unfolding part S3 is inserted into the mold SM3 and moves to the first forming station 1 for forming a capsule or container C3. The first unfolding part S1 located at the third station 3 is removed in the form of a formed capsule C1. It can be removed by vacuum suction or mechanical extraction. Step 4 – Empty: When the rotating die 220 rotates one more step in the first revolution, it is empty, but a new unfolding part will be filled in during subsequent rotations. In this step 4, the second unfolding part S2, which is housed in the mold SM2 located in the third position 3, is removed in the form of a pre-formed capsule C2. It can be removed by vacuum suction or mechanical extraction.

[0073] To produce the first capsule C1, the mold must be opened and closed three times, but after that, one finished capsule can be produced in each cycle. Therefore, to ensure processing continuity, a fourth station is needed that does not perform any processing to avoid any downtime. Since there are three active processing steps (forming, de-wrinkling, and removal), a fourth station is required to start the next processing cycle when the first finished product is removed. After the first incomplete cycle, the subsequent three active processing cycles (forming, de-wrinkling, and removal) can be performed simultaneously.

[0074] Otherwise, a new processing cycle can only begin after the mold in step 3 has been released. It can be deduced that the different movements of the rotating die and different machining tools can be performed in any known manner. For example, the rotating die can be driven to rotate by an electric motor, and the machining tools (or punches) can be controlled by an electric motor or a pneumatic motor.

[0075] As mentioned above, Figure 6 shows the movable punch 210 in a top view. Figure 6a The division of moving sectors can be observed in this figure.

[0076] Specifically, Figure 6b The initial position of the movable punch 210 is shown, with the center portion 212 retracted and the forming portion 214 extended.

[0077] on the other hand, Figure 6c The movable punch 210 is shown in its final position. The sector expands to form a capsule.

[0078] Specifically, the movable punch 210 is generally truncated conical tube in shape with a circular cross-section.

[0079] In the embodiment illustrated herein, the molded portion 214 (i.e. the exterior) is formed by three tubular elements 214a with a circular cross-section, which are joined together by three tubular elements 214b with an arrow-shaped cross-section.

[0080] The three tubular elements 214a with circular cross-sections have a central toothed protrusion on the chord portion.

[0081] Finally, the central portion 212 of the movable punch 210 is generally tubular with a hexagonal cross-section, wherein each side of the hexagon is provided with a groove, which is adapted to engage with the central toothed protrusion of the tubular element 214a with a circular cross-section and the arrow tail of the tubular element 214b with an arrow-shaped cross-section.

[0082] The groove on the central portion 212, which has a hexagonal cross-section, serves as a guide for the toothed protrusion and the arrow tail to slide.

[0083] Figure 7 shows the second known type of coffee capsule (CC).

[0084] Figure 7f The preparation of Figure 7a and Figure 7b The unfolded part SC of a known spherical coffee capsule CC of the type shown.

[0085] Figure 8 The mold SM and punch PUNZ assembly for the spherical capsule CC in Figure 7 are shown.

[0086] In this example, to prepare the hemispherical capsule CC, the punch in step 1 is divided into two parts, while the punch in step 2 is a single piece, and the die gap is 0.12mm.

[0087] Figure 9 shows another container that can be obtained through the scheme described herein, specifically a fruit puree box CF.

[0088] Figure 9d The preparation of Figure 9a and Figure 9b The unfolded component SF of the fruit puree container CF.

[0089] Figure 10a The mold SM is shown. Figure 10b The preparation of Figure 9a and Figure 9b For the fruit puree, use the CF punch punch.

[0090] Figure 10c and Figure 10d Top views of the die SM and the punch PUNZ are shown respectively.

[0091] In the case of preparing fruit bowls or fruit boxes (CF), the punch remains fixed in the first forming step, and the second punch approaches zero distance to compact the paper. Except for the difference in the gap between the punch and the die in the two cases (the gap is 1.2 mm in step 1 and 0.2 mm in step 2), the rest are similar.

[0092] Figure 11 shows another container C that can be obtained through the scheme described herein, specifically a cup lid CB for transporting hot or cold drinks. Figure 11f The preparation of Figure 11a and Figure 11e The unfolded part SB of the middle cup lid CB.

[0093] Figure 12a The mold SM is shown. Figure 12b The assembly of a mold SM and a punch PUNZ for preparing a cup lid CB (e.g., for hot or cold drinks for transport) is shown.

[0094] In this example, in order to prepare the cup lid, the punch used for forming step 1 is divided into four parts, while the punch used for step 2 is a single piece to compact and remove texture.

[0095] The punch is equipped with a spring system to lower the first central part first, followed by the rest of the parts, so as to fold the paper slightly each time to obtain the desired profile.

[0096] The clearance difference between the punch PUNZ and the die SM depends entirely on the thickness of the paper used. The concept is that, in the forming step 1 above, the punch 210 has a large clearance to prevent the paper from tearing, while in the de-wrinkling step 2, the punch 230 presses the workpiece to remove all residual wrinkles from the paper.

[0097] Regarding indentations on paper (see...) Figure 3b , Figure 4a and Figure 4bIt is not always necessary, depending on the type of workpiece to be prepared. Clearly, each die SM and each punch PUNZ has specific characteristics, and when they work together, they can deeply draw the unfolded part S, thereby producing a 3D finished product with the desired shape.

[0098] As described above, the preparation of 3D products consists of two steps: a first forming step through "folding" and a second "pressing" step to remove all the wrinkles generated in the folding step.

[0099] For the folding step, the gap between the punch and the die is between 1.5 and 2 times the thickness of the paper. For example, if the paper thickness is 1 mm, the gap can be between 1.5 mm and 2 mm.

[0100] For the pressing step, the gap between the punch and the die is between 0.5 and 0.8 times the thickness of the paper. For example, if the paper thickness is 1 mm, the gap between the punch and the die can be between 0.5 mm and 0.8 mm.

[0101] The coating material Q applied to the paper will be described below.

[0102] The coating material Q has two functions: protecting the capsule CC or container C from water intrusion and allowing "paper to be glued", especially at the intersection and overlap of the unfolded parts S.

[0103] The coating material Q is a sol, a viscous solution containing silicon compounds. During the deposition process on the paper, these silicon compounds undergo a condensation reaction to form a three-dimensional lattice of silicon-oxygen bonds. Depending on the exact composition of the initial sol, some of these silicon-oxygen bonds may be replaced by bonds between silicon and other types of groups (typically alkyl groups). This three-dimensional lattice structure forms a glassy layer on the paper surface at a macroscopic level, preventing liquid penetration.

[0104] The sol can be prepared by dispersing or dissolving at least one alkyltrialkoxysilane and at least a second component in water or a water-alcohol mixture, wherein the second component is selected from micron-sized silica, tetraalkoxysilane, or both micron-sized silica and tetraalkoxysilane.

[0105] Micron-sized silica (also known in the art as "colloidal silica" or "fumed silica") is a form of silica comprising primary particles of silica at the nanoscale (i.e., smaller than 1 micrometer, µm) that typically aggregate to form micron-sized secondary particles. This material is widely available on the market, for example, under the AEROSIL brand from Evonik Resource Efficiency GmbH in Essen, Germany. ®Trademark sales (e.g., AEROSIL) ® OX 50 products), or products manufactured by Cabot Corporation, located in Boston, Massachusetts, USA, under the name Cab-O-Sil. ® Trademark sales.

[0106] Tetraalkoxysilanes are compounds with the general formula Si(OR)4, wherein R is usually a C1-C6 alkyl group, preferably a C1-C2 alkyl group.

[0107] Alkyltrialkoxysilanes are compounds of the general formula R'-Si(OR)3, wherein R and R' are the same or different from each other, and are usually C1-C6 alkyl, preferably C1-C2 alkyl.

[0108] Tetraalkoxysilanes and alkyltrialkoxysilanes are also widely available products.

[0109] The sol suitable for the purposes of this invention can be obtained by following the method described in the applicant's patent application WO 2022 / 171893 A1, which involves dissolving or dispersing 25% to 40% by weight of an alkyltrialkoxysilane and a second component in water, the second component being selected from micron-sized silica, tetraalkoxysilane, or both micron-sized silica and tetraalkoxysilane. The amount of micron-sized silica (if present) is between 5% and 20% by weight of the sol, while the amount of tetraalkoxysilane (if present) is between 15% and 25% by weight of the sol. Optionally, one or more other components may be added to the sol. These one or more other components are selected from C1-C6 alcohols or mixtures thereof, and bases selected from the group consisting of NaOH and KOH, wherein the amount of base added is such that the pH is adjusted to a range of 2 to 5.

[0110] Once applied to paper, heating can initiate the condensation reaction that forms the glassy layer described above. The heating temperature is typically between 100°C and 250°C, preferably between 150°C and 200°C. When the heating temperature exceeds approximately 230°C (the auto-ignition temperature of paper), the heating must be carried out rapidly and only for a period sufficient to evaporate the liquid components in the initial sol.

[0111] As mentioned above, the present invention always uses coated paper, which can improve the coating effect of coating material Q and obtain better adhesion.

[0112] An example of coated paper is INVERCOTE G manufactured by IGGESUND, with a basis weight of 530 g / m². 2 .

[0113] In summary, the preparation steps for 3D products are as follows: - This method begins with paper sheets or rolls; specifically, when the paper's basis weight is greater than 450 g / m². 2 Start with a piece of paper; when the paper's basis weight is less than 400 g / m²... 2 When using rolls (paper rolls), start with rolls.

[0114] - All sides of the paper are impregnated with coating material Q.

[0115] - The wet paper enters the mold, and the following steps are performed here: - Die-cutting, - Folding, and - Suppression.

[0116] Between the folding and pressing steps, all steps are performed synchronously with the rotation of the mold. The mold is hot, at a temperature of approximately 150 °C. When paper impregnated with coating material Q is folded and then pressed, the coating material Q penetrates into all fibers and cures due to the temperature of the mold, giving the paper excellent heat resistance, water resistance, and oil resistance, and improving the paper's rigidity and mechanical properties.

[0117] The description of the specific embodiments provided above has illustrated the invention conceptually, enabling those skilled in the art to modify and / or adjust these specific embodiments to suit different applications without further study and without departing from the inventive concept. Therefore, it should be understood that such adjustments and modifications should be considered equivalent to these specific embodiments. The devices and materials that achieve the above functions may have various properties, but do not deviate from the scope of protection of this invention. It should be noted that the terms or expressions used in this document are for descriptive purposes only and are therefore non-limiting.

[0118] Obviously, without affecting the principles of the present invention, various changes can be made to the structural details and embodiments of the present invention relative to the content described and illustrated above by way of example, but these changes will not depart from the protection scope of the present invention.

[0119] If the structural and technical features described in the following claims are followed by reference numerals or numbers, the reference numerals are added only to improve the comprehensibility of the claims themselves, and therefore the reference numerals do not limit the interpretation of the elements exemplified thereon.

Claims

1. A method for preparing thermoformed 3D workpieces made of thick coated paper, wherein the basis weight of the coated paper is selected from 180 g / m³. 2 Up to 1010 g / m 2 Within the scope, the following steps are included: Thick paper (F, B) in the form of single sheet (F) or roll (B) is supplied to machine (M, M1); The paper is die-cut (10, 200) to prepare a planar unfolded part (S) of the 3D workpiece to be formed; Upstream or downstream of the die-cutting process, a coating material (Q) is applied to the paper (F, B) or the planar unfolded part (S), wherein the coating material (Q) is a sol, i.e., a viscous solution comprising a silicon compound, which undergoes a condensation reaction in a subsequent stage after deposition onto the paper to form a three-dimensional lattice with silicon-oxygen bonds, wherein, depending on the exact composition of the initial sol, some silicon-oxygen bonds can be replaced by bonds between silicon and other substances, said other substances being alkyl groups; The planar unfolded part (S) covered with the coating material (Q) is placed into a heated mold (30, SM). The planar unfolded part (S) is deep drawn in the mold (30, SM) using a punch (50, PUNZ), wherein the deep drawing step includes: a first forming step using a first punch (210), the first punch having a clearance relative to the die (SM) constituting the mold being 1.5 to 2 times the thickness of the paper; and a second pressing step using a second punch (230), the second punch having a reduced clearance relative to the die (SM) constituting the mold being 0.5 to 0.8 times the thickness of the paper, to remove all wrinkles generated in the forming step, and Remove the thermoformed 3D workpiece from the mold (30, SM).

2. The method for preparing thermoformed 3D workpieces made of thick paper according to claim 1, wherein the coated paper is covered with an extremely thin coating that gives the coated paper a glossy and smooth appearance, wherein the coating is made of a variety of materials, such as kaolin, calcium carbonate, bentonite and talc, and the mineral filler is bonded by latex or a mixture of latex and adhesive.

3. The method for preparing thermoformed 3D workpieces made of thick paper according to claim 1 or claim 2, wherein the paper is single-sided coated paper.

4. The method for preparing thermoformed 3D workpieces made of thick paper according to claim 1 or claim 2, wherein, The paper is double-coated paper.

5. The method for preparing a thermoformed 3D workpiece made of thick paper according to any one of the preceding claims, wherein, The mold is heated to a temperature between 100°C and 250°C, preferably between 150°C and 200°C, so that the coating material (Q) is transformed into a glassy layer.

6. The method for preparing a thermoformed 3D workpiece made of thick paper according to any one of the preceding claims, wherein, The first punch (210) is a movable punch composed of multiple components (212, 214), which intervene in the operation at different times.

7. A machine (M, M1) for preparing thermoformed 3D workpieces made of thick paper, comprising stations for the following operations: Supply of thick coated paper, wherein the basis weight of the coated paper is selected from 180 g / m². 2 Up to 1010 g / m 2 The scope is available in paper (F) or roll (B) form; The paper is die-cut (10, 200) to obtain a planar unfolded part (S) of the 3D workpiece to be formed; Upstream or downstream of the die-cutting operation, a coating material (Q) is applied to the paper (F, B) or the planar unfolded part (S), wherein the coating material (Q) is a sol, i.e., a viscous solution comprising a silicon compound, which undergoes a condensation reaction in a subsequent stage after deposition onto the paper to form a three-dimensional lattice with silicon-oxygen bonds, wherein, depending on the exact composition of the initial sol, some silicon-oxygen bonds can be replaced by bonds between silicon and other substances, such as alkyl groups. The 3D workpiece was obtained by molding using a heated mold (30, SM). Deep drawing is performed using a punch (50, PUNZ) and a die (SM), and the deep drawing station includes: A first forming step is performed using a first punch (210), the first punch having a clearance relative to the die (SM) constituting the mold being 1.5 to 2 times the thickness of the paper; and a second pressing step is performed using a second punch (230), the second punch having a reduced clearance relative to the die (SM) constituting the mold being 0.5 to 0.8 times the thickness of the paper, to remove all wrinkles generated in the forming step, and Remove the thermoformed 3D workpiece from the mold (30, SM).

8. The machine for preparing thermoformed 3D workpieces made of thick paper according to claim 6, wherein, The coated paper is covered with an extremely thin coating that gives the coated paper a glossy and smooth appearance. The coating is made of a variety of materials, such as kaolin, calcium carbonate, bentonite, and talc, and the mineral filler is bonded by latex or a mixture of latex and adhesive.

9. The machine for preparing thermoformed 3D workpieces made of thick paper according to claim 8 or 9, wherein, The paper is single-sided coated paper.

10. The machine for preparing thermoformed 3D workpieces made of thick paper according to claim 8 or 9, wherein the paper is double-coated paper.

11. The machine for preparing thermoformed 3D workpieces made of thick paper according to any one of claims 8 to 11, wherein the station for coating the coating material (Q) has coating rollers (20, 110).

12. The machine for preparing thermoformed 3D workpieces of thick paper according to any one of claims 8 to 12, wherein the mold is heated by a resistor to a temperature between 100°C and 250°C, preferably between 150°C and 200°C, to transform the coating material (Q) into a glassy layer.

13. The machine for preparing thermoformed 3D workpieces made of thick paper according to claim 12, wherein, The first punch (210) is a movable punch composed of different components (212, 214), which are engaged at different times.

14. A thermoformed 3D workpiece made of thick paper, said thermoformed 3D workpiece being manufactured by the method according to claims 1 to 6.

15. A thermoformed 3D workpiece made of thick paper, said thermoformed 3D workpiece being manufactured by the machine according to claims 8 to 13.

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