Multilayer materials for press molding, delivery systems, and resulting textile products

Abstract

This invention relates to multilayer materials for press molding, a delivery system, and the resulting textile products. A recovery method is also disclosed.

Description

[Technical Field]

[0001] The present invention relates to a material for press-forming textile products intended to be formed at high pressure and high temperature, preferably using a press pad device and a stamping device, thereby producing textile products. The present invention also relates to an efficient delivery system for such press-forming and the resulting products with improved mechanical and resistant properties. The present invention also relates to a three-layer material concept for improving product properties and recyclability. The present invention also relates to a recovery method. [Background technology]

[0002] Textile products can be made by pressing a web or sheet of fibers. Typically, combinations of natural fibers (e.g., wood pulp fibers), synthetic fibers (e.g., polyolefin-based fibers, which may be polyethylene or polypropylene, polyethylene terephthalate), and other additives such as binders or dyes are possible. In some applications, it is preferable that such webs essentially consist of natural fibers, with or without additives. Typical processing conditions are 150–250°C and a pressure of 100–10000 bar (200–2000 bar). The moisture content can usually be less than 20%. In many applications, the material is produced in an integrated operation with the pressing operation to provide sufficient molding flexibility by using a material with slight internal strength.

[0003] Examples of the known methods described above are shown in European Patent Application Publication No. 3736099 and International Publication No. 2020 / 165780. Textile products can be in the form of hollow products, such as packages or closures (lids, screw-on caps, etc.), but can also be flat products. Products are formed from a web of material and can be punched / cut in connection with the forming process. For example, this is completely or partially separated from the web to allow for deeper forming. This exposure is usually done by cutting the material into a shape that will adapt to the final shape very close to the forming process. Typically, for example, a circle is cut to form a circular package.

[0004] Press forming is typically performed using two tools, both of which may consist of several parts that allow the finished product to be ejected. Typically, the pad opens while the stamp contracts. The piston, part of the piston, or part of the pad can also be made from a compressible material, which usually allows for greater perpendicular compressive force to the sides of the cavity by the tool material that shapes it during compression.

[0005] If the material is not produced (or laid) in the immediate vicinity of, or on the same line as, the stamping and molding processes, it must have a certain strength (physical properties) to withstand operations such as production, drying, cutting to roll width, winding, unwinding, cutting to blank, and feeding. Typically, the material is exposed to tension from cutting and handling, from line tension and shear forces.

[0006] Furthermore, the material will require a certain degree of rigidity, primarily bending rigidity, for handling and supply operations, for example. In particular, the surface of the material is at risk of interlocking or fusing with contact surfaces when stored, for example, on rolls or on shipping pallets, resulting in the material being difficult to separate, generating dust when separated, or being damaged while separated. This is a known problem with high-strength materials, known as blocking, but the problem is considerably greater with soft or ambiguous materials typically used in press forming.

[0007] Typically, fibrous materials for 3D-pressed or folded packaging products are delivered flat in one of three main methods: rolls, sheets, or blanks. A drawback of existing methods is the poor volumetric efficiency of the rolls, both due to the circular shape of the rolls themselves and the voids created by the central unwinding core. While blanks and sheets can offer significantly higher volumetric efficiency, the nature of this system means the material is cut into individual items, further complicating the supply system, increasing complexity, cost, and production efficiency.

[0008] When a material is formed into a product, the internal bonding between some fibers needs to be low or nonexistent. This is because the shape of the material changes piecewise as the fibers are partially rearranged, or at least their bonds are broken, for example, by delamination. Since fiber-based materials generally tend to weaken with high moisture content, there is an optimal moisture content for the material during press forming. This imposes special requirements regarding the original strength and relative wet strength of the incoming material.

[0009] The final product must possess certain minimum strength and resistance characteristics. These are partially derived from processing parameters such as pressure, temperature, and molding time, but also from the material composition and additives. In some applications, strength and resistance characteristics may need to be higher on the surface, either on the top and bottom of the product or on the inside and outside of the product. For example, a packaged product experiences extra stress outward from handling and also inward from interaction with the packaging. In items with some types of closing mechanisms, stress arises from the interaction of different parts of the opening mechanism, such as the interaction between the lid and the container, or the interaction between the inside and outside threads.

[0010] Much of the final product is recycled, the fibers are separated and used in new products. This imposes special requirements on products where only the minimum amount of fibers are joined so that they cannot be separated during the recycling process, usually the repulping process. Repulping has the advantage that, since it benefits from thinner materials and objects, when a weak layer is introduced, the object, and the resulting strong layer, can be better exposed to the repulping process and separated more efficiently.

[0011] Therefore, there remains a need to provide products that are easily recyclable and / or compostable. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] European Patent Application Publication No. 3736099 [Patent Document 2] International Publication No. 2020 / 165780 [Overview of the Initiative]

[0013] The present invention solves / mitigates one or more of several problems by providing a multilayer substrate according to a first aspect, the multilayer substrate comprising at least one layer that provides tensile strength and one layer containing fibers that have internal strength low enough to be formed by a press molding operation, thereby forming new bonds at new relative positions, at least partially.

[0014] Furthermore, according to a second aspect of the present invention, a method is provided for processing a multilayer substrate described in any one of the prior claims for providing a multilayer product, the method comprising the following steps, namely: a) the step of providing the multilayer substrate, b) The step of exposing the substrate to high pressure, c) Providing a multilayer product by exposing the substrate to a high temperature, wherein optionally, pre-expanded microspheres and / or expandable microspheres are added, preferably before providing the multilayer substrate in step a), or simultaneously with providing the microspheres in step a), most preferably before providing the multilayer substrate in step a), Includes.

[0015] Furthermore, according to a third aspect of the present invention, a multilayer product that can be obtained by the method according to the second aspect is provided.

[0016] Furthermore, according to a fourth aspect of the present invention, the use of a multilayer product is provided by a method according to the third aspect, the product being part(s) of a molded product such as a lid, screw cap, container, bread clip, or package, the container being a disposable cup or dairy pack or autoclave package or tray, or a plate for eating or storing food, or paper or cardboard such as foldable cardboard.

[0017] Also, according to a fifth aspect of the present invention, there is provided a method for recycling a multilayer product according to a third aspect for providing recycled pulp, the method comprising the following steps, namely: i) preferably, after use of the multilayer product, providing the multilayer product; ii) submerging the product in a liquid, preferably water, most preferably warm water; iii) optionally, adding one or more decoupling agents to the liquid; iv) providing recycled pulp by exposing the product to shear forces in the liquid. This includes.

[0018] Detailed description of the present invention The terms "fibre" or "fiber" may be used interchangeably herein and will have the same meaning. The terms "mold" or "mould" may be used interchangeably herein and will have the same meaning.

[0019] According to a preferred embodiment of the first aspect, the multilayer substrate comprises at least one layer with pre-expanded microspheres and / or expandable microspheres.

[0020] According to a preferred embodiment of the first aspect, the multilayer substrate comprises at least one layer with a fiber mat produced by airlaid technology and / or a fiber mat produced by wetlaid technology.

[0021] According to a preferred embodiment of the first aspect, the multilayer substrate includes at least one layer with a paper sheet, preferably the sheet has a moisture content of about 4% to about 25%, most preferably about 7% to about 15%.

[0022] According to a preferred embodiment of the first aspect, the expandable microsphere is a thermally expandable thermoplastic microsphere, or a pre-expanded thermally expandable thermoplastic microsphere, or a combination thereof. The expandable thermoplastic microsphere may be made of fossil material or biopolymer material. An example of such expandable microspheres is the microspheres marketed by Nouryon under the name "Expancel Microspheres".

[0023] According to a preferred embodiment of the first aspect, the layer providing tensile strength provides tensile strength at least about 10%, preferably at least about 20%, and most preferably at least about 50%, higher than the tensile strength of the other layers.

[0024] According to a preferred embodiment of the first aspect, the substrate is a three-layer material. The substrate may further have more than three layers, for example, four, five, six, seven, eight, nine, or ten layers. Preferably, at least one of the layers of the at least three-layer material comprises at least one fossil-based and / or bio-based polymer and / or a biodegradable polymer, such as PET (polyethylene terephthalate) or one or more polyolefins, the biodegradable polymer being selected from the group including PLA (polylactic acid), PHBH (poly(3-hydroxybutyrate-co-3-hydroxyhexanoic acid)), PHA (polyhyaluronic acid), and PEF (polyethylene furanoate), or combinations thereof.

[0025] Non-limiting examples of polyolefins include polyethylene (PE) and polypropylene (PP). The polymer may be added in pellet form before pressing, or in the form of solid foil (before or after pressing). This will face the contents of the container when at least three layers of material are used in food applications, such as milk caps or other dairy products. When foil is used, lamination occurs, and the polymer then faces the food product. The polyethylene may preferably be bio-based. The polymer material may further improve the rigidity of the at least three-layer material. Furthermore, PET / PE composite materials may be used. Additionally, binders such as EVA, latex, or starch may be suggested. Also, in the above context, lyocell may be used.

[0026] According to a preferred embodiment of the first aspect, the high tensile strength is provided by at least one of the outer layers, preferably with a minimum tensile strength of about 75 N / m(CD) (CD = cross-machine direction).

[0027] According to a preferred embodiment of the first aspect, the high tensile strength is provided by two outer layers, preferably with a total minimum tensile strength of about 150 N / m (MD). Thus, the outer layer provides about 75 N / m, while the intermediate layer provides essentially less (MD = machine direction).

[0028] According to a preferred embodiment of the first aspect, the layer(s) with high tensile strength is thinner than the middle layer(s).

[0029] According to a preferred embodiment of the first aspect, a material with low initial tensile strength provides one or more layers that are well repulped.

[0030] According to a preferred embodiment of the first aspect, at least one of the outer layers has high hydrophobicity and / or oleophobicity by using a water-repellent and / or oil-repellent agent such as AKD (alkyl ketene dimer), ASA (alkenyl succinic anhydride), or wax, or latex, or rosin, or bio-based fiber, or cellulose acetate, or a combination thereof. This can be achieved for at least one or both of the outer layers as follows:

[0031] In this method, large cellulose-based materials (approximately 7-8 cm) 3 The material (which may have a specific volume of 1 / g) is pressed after passing through a decurler unit, thereby applying water-repellent and / or oil-resistant agents before pressing (e.g., using a spray). The cellulosic material may be wet or airlaid. A combination of pressure (about 10 to about 100 MPa, preferably about 20 to about 30 MPa) and heat (about 120 to about 250°C, preferably about 120 to about 180°C) is applied to the material in 0.5 to 2 s, thereby producing a high-density cellulose material (about 1.11 to about 1.25 kg / dm³) with relatively limited porosity and a relatively non-capillary structure. 3 This process occurs. This process affects the material in several ways, including the following: a) The high temperature used to press the material allows the fiber mat to heat above the melting point of the chemicals used for water / grease repellency. This allows the chemicals to be redispersed / diffused more evenly on / around the fibers during pressing, reaching a more homogeneous area of ​​the fibers, and thus enabling high hydrophobicity and / or oleophobicity. b) Extremely high density in the material during pressing results in a smooth, closed-surface object with a low specific volume compared to other cellulosic materials such as cardboard or wet-molded cellulose. The high density of the fiber network allows for the creation of a network of hydrophobic and / or oleophobic agents (i.e., water-repellent and / or oil-resistant agents) around the fibers, and then, due to the lack of space available for the flow of these agents, the agents are trapped within the structure. Furthermore, the smooth, closed surface further reduces the possibility of flow, trapping the agents within the material, and similarly, the possibility of hydrolysis is reduced, thus improving performance. Finally, the high density of the material increases the volume fraction of hydrophobic and / or oleophobic agents (i.e., water-repellent and / or oil-resistant agents) in a given amount of material, resulting in further high density of the network and improved performance.

[0032] A decaler unit that may be used in connection with the method described above may be, for example, a roll decal component provided by Maxson Automatic Machinery Company, or a decal unit provided by Ricoh. The decal unit may include one sponge roller, two metal rollers, and two paths for paper or other cellulosic materials. The strength and curl direction of the decal may be adjustable. It may be a “sandwich” configuration in which an upper pressure roller, a decal roller, and a lower roller are present. The decaler (or decaler unit) exerts a mechanical effect on the fibers, meaning that any bending that initially occurs in the fibers can, in essence, be removed using the decaler.

[0033] Furthermore, the above method can be expressed as follows:

[0034] A method for improving the water and / or grease repellency of a material suitable for packaging purposes comprises the following steps: a) preferably a step of providing a material containing cellulosic fibers, b) The step of passing the material through a decurler unit, c) The step of spraying water and / or a grease water repellent onto the treated material, d) A step of providing a product in which the water repellency of water and / or grease is improved, for example, in food or beverage packaging solutions, by exposing the material treated with the water repellent to high pressure and high temperature, Includes.

[0035] In this method, preferably, the high pressure and high temperature in step d) are provided by a press pad device and a stamping device. The most preferred high pressure and high temperature in step d) is a combination of a pressure of about 10 to about 100 MPa, preferably about 20 to about 60 MPa, most preferably about 30 to about 60 MPa, and a temperature of about 80 to about 250°C, preferably about 120 to about 250°C, most preferably about 120 to about 180°C, thereby preferably the conditions are maintained for a period of about 0.5 to about 2 seconds.

[0036] In this method, the base material is derived from chemothermetic pulp, thermomechanical pulp, kraft pulp, sulfate pulp, sulfite pulp, recycled pulp material, board or cardboard, or a combination thereof. The material may also be derived from bleached or unbleached pulp, or a combination thereof. Furthermore, the base material may be derived from hardwood or softwood, bagasse paper, algae or straw, or a combination thereof.

[0037] In this method, preferably, the material provided in step a) is preferably an airlaid material containing cellulosic fibers, or preferably a wetlaid material containing cellulosic fibers, or a combination thereof, and preferably, the material provided in step a) is about 7-8 cm 3 It has a specific volume of / g.

[0038] As described above, the water and / or grease water repellent is preferably one or more sizing agents selected from the group comprising alkyl ketene dimers (AKD), alkenyl succinic anhydrides, and waxes, or combinations thereof.

[0039] The method described above may provide, for example, a product using the following characteristics: a material preferably containing cellulose fibers with improved water and / or grease repellency suitable for packaging purposes, with a density of approximately 1.11 to approximately 1.25 kg / dm 3 It has a density, which is preferably achieved by using one or more water and / or grease water repellents, preferably one or more sizing agents, due to the improved water repellency.

[0040] The product, which has improved water and / or grease repellency, can be obtained by the method described above.

[0041] The product, which has improved water and / or grease repellency as described above, may be part of a molded product such as a screw-on cap, container, bread clip, or package, the container may be a disposable cup or dairy carton or autoclave package or tray, or a plate for eating or storing food, or paper or cardboard such as foldable cardboard.

[0042] The product, which has improved water and / or grease repellency as described above, can be used in multilayer structures such as screw-on caps, containers, bread clips, or three-layer molded products such as packaging, where the container may be a disposable cup or dairy pack or autoclave package or tray, or a plate for eating or storing food, or paper or cardboard such as foldable cardboard, preferably the layer with improved water and / or grease repellency is in contact with food or beverages during the purchaser's final use.

[0043] Furthermore, the multilayer product may be provided such that one of the outer layers forms a thread or click-on function for sealable packaging, such as a container, a closure, or part of a container or closure.

[0044] As described above, hydrophobicity can be achieved, for example, by using AKD and / or wax and / or bio-based fiber and / or lignin. Also, products using click chemistry can achieve hydrophobicity alone or in combination with a binder. Also, sol-gel treatment can be used to achieve the water-repellent effect of the press material. As an example of AKD, there is the abbreviation AP, and as an example of wax, there are the abbreviations AS or ASCL when combined with a binder.

[0045] According to a preferred embodiment of the first aspect, at least one of the outer layers has a high relative wet strength.

[0046] According to a preferred embodiment of the first aspect, at least one of the outer layers has a high density.

[0047] According to a preferred embodiment of the first aspect, the density is lower than about 0.5 kg / dm 3 and preferably about 0.1 to about 0.4 kg / dm 3 is.

[0048] According to a preferred embodiment of the first aspect, the basis weight is about 100 to about 2000 g / m 2 and preferably about 300 to about 1500 g / m 2 is. When using tissue paper as the starting material for one layer, preferably the outer layer, it can have a basis weight of about 15 to about 18 g / m 2 and preferably about 16.5 g / m 2 has.

[0049] According to a preferred embodiment of the first aspect, the moisture content is about 4 to about 25%, preferably about 7 to about 15%.

[0050] According to a preferred embodiment of the first aspect, at least one of the outer layers contains one or more additives for extra strength and wet strength, and preferably at least one component of the additive(s) contains fibers of artificial polymer.

[0051] In the embodiment of the first aspect, the substrate described above may be made from CTMP (chemothermetic pulp), TMP (mechanical pulp), kraft pulp, sulfate pulp, sulfite pulp, recycled pulp material, pulp for board or carton, or a combination thereof. Furthermore, the substrate may be made from bleached pulp or unbleached pulp, or a combination thereof. In addition, the substrate may be made from hardwood or softwood, bagasse paper or straw, or a combination thereof.

[0052] According to a preferred embodiment of the second aspect, the method includes the following steps when at least one layer comprises a pre-inflated microsphere and / or an inflatable microsphere. d) The multilayer substrate is provided to a mold assembly and the material is heated to about 50 to about 150°C, preferably about 60 to about 120°C, most preferably about 80 to about 100°C, thereby providing a dry content of about 50 to about 70%, and consequently providing an expanded product or foamed multilayer product.

[0053] According to a preferred embodiment of the second aspect, steam is added in step d) to expand the multilayer substrate.

[0054] According to a preferred embodiment of the second aspect, the high pressure and high temperature of step b) and / or c) are provided by the press pad device and the stamp device.

[0055] According to a preferred embodiment of the second aspect, the substrate is made from CTMP (chemothermetic pulp), TMP (mechanical pulp), kraft pulp, sulfate pulp, sulfite pulp, recycled pulp material, board or carton, or a combination thereof.

[0056] According to a preferred embodiment of the second aspect, the substrate is made from bleached pulp, unbleached pulp, or a combination thereof.

[0057] According to a preferred embodiment of the second aspect, the base material is made from a hardwood or softwood, bagasse paper, algae or straw, or a combination thereof.

[0058] According to a preferred embodiment of the second aspect, prior to step a), a delivery step is performed which includes forming the substrate into a strip, and then folding the strip.

[0059] According to a preferred embodiment of the third aspect, the product according to the third aspect is a molded product such as a screw-on cap, container, bread clip, or package, the container may be a disposable cup or dairy pack or autoclave package or tray, or a plate for eating or storing food, or paper or cardboard such as foldable cardboard.

[0060] According to a preferred embodiment of the third aspect, the multilayer product is provided such that one of the outer layers forms a thread or click-on function for sealable packaging, such as a container, a closure, or part of a container or closure.

[0061] The present invention provides a material usable in press molding operations that allows for partial separation and re-bonding of fibers, which is produced to have high tensile strength, shear strength, and surface strength, and can be supplied to the molding operation in an efficient manner. Furthermore, the outer layer and surface properties of the molded product can be sufficiently strong and resistant while minimizing the amount of reinforcing agent, and high repulsion and thus high recyclability can be maintained.

[0062] In one application of the present invention, a multilayer material is folded during or before pressing and forming operations, thereby creating a strong internal material structure in which the outer layers interact. In this way, the structure can be locally reinforced while minimizing the use of strength additives and maintaining recyclability.

[0063] The novel material of the present invention, with its tensile strength and handling properties, enables a new delivery system in which the material can be delivered in folded strips on a pallet. This brings two distinct advantages to the production of items, particularly high-volume packaged items. The delivery method is made possible by using a strong yet flexible material resulting from a multilayer structure, which in this case enables a highly volumetrically efficient system due to its strength and ability to fold without creating creases that affect the final product. The volumetric efficiency of sheets on a pallet is combined with the production advantages associated with continuous material supply from rolls to create continuous blocks of material by folding.

[0064] Moisture content (as described in relation to the specific embodiments above) provides advantages during press forming (see a second aspect of the present invention). Preferably, the moisture is added before the pressing of the substrate (i.e., raw material) is completed.

[0065] Important functions of caps, lids, or similar structures made from fibers include compressibility and dimensional stability. By adding pre-expanded microspheres and / or expandable microspheres to a fiber network, the ability of the compressed material to recover its shape—the so-called bounce-back force—increases. This can also be expressed in a way that influences the viscoelastic properties of the material. As a result, the tendency for time-dependent deformation, the so-called "creep deformation," decreases. Sealed spheres can be added in different ways, for example, to a paper sheet (material). Pre-expanded microspheres and / or expandable microspheres can be added.

[0066] The microspheres may be added during different stages of the manufacturing process. They may be added before the production of the fiber mat, but preferably, they are added in connection with the production of the fiber mat. This can be done while the fiber mat is dry or wet. Alternatively, the microspheres may be added directly during the molding press of the fiber mat. When the product is used in the form of a container closure or sealing member, the additional fibers are added after the molding press. The material may be a fibrous material, preferably a cellulosic material, a polymer material, or a combination thereof.

[0067] Microspheres may be added in an expanded or unexpanded form, or a combination of both. Unexpanded spheres may expand completely or partially by heating during the fiber mat manufacturing process (wet or dry). Spheres may also expand due to the heat transferred during a pressing operation. Alternatively, they may expand in a sealed container before or immediately before a filling or sealing process (see dairy manufacturing processes where dairy products are filled into containers made essentially from cellulosic fibers, and then sealed).

[0068] Next, the final product may contain fully or partially expanded microspheres. Alternatively, it may contain spheres that are expanded and then compressed by a pressing operation.

[0069] Preferred features of each aspect of the present invention are the same as those relating to each of the other aspects, with appropriate modifications. Prior art references made herein are incorporated to the full extent permitted by law. The present invention is further illustrated by the following examples, together with the accompanying drawings, and these drawings and examples are not intended to limit the scope of the present invention.

[0070] Embodiments of the present invention have been described in more detail with reference to examples of embodiments, along with the accompanying drawings, and the sole purpose of such embodiments is to illustrate the present invention and is not intended in any way to limit its scope. [Brief explanation of the drawing]

[0071] [Figure 1] This outlines the production of multilayer materials according to the present invention, in which typically one or both of the outerly molded layers are strong, supporting the other layer which is held loosely together. [Figure 2] The large roll of material, loosely held together internally, is unwound and cut into several smaller rolls, thereby exposing the web to high tension and sharing the forces from the cutting operation, illustrating the approximate cutting process. [Figure 3] This illustrates the schematic shaping process in which partially loosely held fibrous materials are unraveled, cut, pulled, draped, pressed, and, if possible, post-cut to create a multilayer structure with extra strong inner and / or outer surfaces. [Figure 4] This describes a typical multilayer molded structure in which one or both of the outer layers offer high resistance to repulping, while the middle layer is more easily separated, thereby allowing the structure to be delaminated and improving repulping and thus recyclability. [Figure 5] This shows the pressing conditions when creating a proper closure for use of the bottle. [Figure 6] This shows the pressing conditions when creating a proper closure for use of the bottle. [Figure 7] This shows the pressing conditions when creating a proper closure for use of the bottle. [Figure 8] It exhibits hydrophobicity towards the lid. [Figure 9] It exhibits hydrophobicity towards the lid. [Figure 10] It exhibits hydrophobicity towards enclosed objects. [Figure 11] This shows a closure for use in cosmetic containers. [Figure 12] This shows a layered, enclosed structure and the hydrophobic properties emanating from it. [Figure 13] As a further test, the process of creating a coffee lid is shown. [Modes for carrying out the invention]

[0072] Examples 1. Exemplary explanation A. Molding of the first outer or inner layer B. Molding of the second central layer C. Molding of the third outer or inner layer D. Additional manufacturing processes in which the material is exposed to mechanical or chemical stress. Mechanical stress is typically imposed by compressive (calendering) and tensile stress in mechanical or drying operations. Chemical stress is typically imposed by moisture or water, for example, from operations involving the addition of water-soluble or dispersible additives. E. A winding operation in which the material is subjected to tension in order to produce a stable and sufficient roll. If the tension during the winding operation is not high enough, the tension inside the roll will be insufficient to prevent so-called expansion and contraction during handling. F. In the winding operation, web tension is required to pull the material from the larger original roll and must be high enough to generate sufficient web tension on the resulting smaller roll to allow for safe handling. Tension is typically achieved by driving the smaller roll and controlling or braking the rotation of the larger roll. G. Rewinding of the conversion operation. The web tension that generates tension in the material needs to produce a flat and controlled web. This is usually achieved by the material being pulled by the supply unit and the rolls being restrained by a braking mechanism. With regard to rewinding, the layers of the rolls on which the inside of the material is facing outwards need to be separated, which generates not only tension but also planar external forces or shear forces, and if the surface strength of the material is not high enough, there is a risk that the material will break, generate dust, or that part of one surface will adhere to the other surface. H. In some operations, the material is cut into blanks before the supply operation that generates tension and shear forces on the material. I. The material, as a web or sheet (or blank), is typically fed into the press operation (J) by a push operation of a feeder, ensuring that no tension is applied. The material is then punched or draped to form a mold (see “Press Pad Device” in Figures 1 and 2). The push operation generates compressive and buckling forces in the material, and when fed, the material is required to be strong and rigid enough not to compress, fold, or buckle. J. Pressing device (see also Figures 1 and 2 below). The material is typically pressed flat into the pressing area and then pressed or draped into the press pad device using a stamp or specialized tool. The material must be strong enough not to break from the tension or shear force generated from the brake press device and the pad walls, while at the same time being loose enough so that a considerable amount of fibers can be rearranged during the pressing operation. During the pressing operation, the material is formed and new bonds are created. The properties of the material and the additives added determine the characteristics of the new laminate structure. Typically, the material may include strength, wet strength, and hydrophobicity, making it strong and / or resistant to water, while materials without these additives will produce properties that allow for good repulping. When the material is folded in the pressing or draping operation, the inner or outer material becomes a fold that is in direct contact with itself, usually creating a strong reinforcing structure. K. In forming and pressing operations, the outer and / or inner layers typically produce a multilayer structure with extra strength from additives initially added during the manufacturing and transformation operations to create one or more strong layers. If the formed item is cut after forming, the strength of the outer(s) layers assists the cutting operation with good shear and bend resistance. The molded product will benefit from its extra strength. As an example of non-limiting cases, the minimum tensile strength could be 150 N / m(MD) in total, and essentially, the intermediate layer would have no strength. Therefore, each outer layer would have a tensile strength of approximately 75 N / m(CD). L. After use, the fibers of the item need to be recycled and made available for new use as packaging or other products. This is usually done by the item being collected, transported, and repulped together with other fiber and paper products. Repulping, which constitutes a fifth aspect of the present invention, is usually carried out by submerging the item in warm water and exposing it to shear forces that separate the fiber bonds, with or without decoupling agents. Generally, strong bonds, bonds assisted by additives, and thick structures make repulping difficult. M. In multilayer structures where one or more layers are easily peeled, they are peeled or partially peeled, and the layers that are easily repulped separate into single fibers. Layers that are difficult to separate eventually become thinner layers or flakes, and due to their geometric changes, these layers separate more easily into single fibers than if they were maintained in a thicker structure. If all or part of the strong layers do not separate entirely, these are sorted, allowing the main part of the structure to be recycled into new paper or textile products.

[0073] 2. Measurement If an airlaid test material (carrier sheet), which is a multilayer material according to the present invention, is processed during testing and subsequently measured for tensile strength, for example, as performed on all materials (including tissue), data (test results) can be collected, which may be expressed as follows:

[0074] [Table 1]

[0075] The extensibility and breathability of the tissue carrier are two important parameters for conversion in an air-laid machine.

[0076] Additional measurements for an exemplary thermally coupled airlaid tissue carrier are given below.

[0077] [Table 2]

[0078] 3. Tests using hydrophobic materials Materials treated with various hydrophobic products were manufactured or pressed to fit lids or screw-on caps.

[0079] The materials were treated on one or both sides with click chemical products, either with AKD(AP), wax dispersion (AN), or with or without additional binders (ASCL). The percentage (dry weight ratio) of the added hydrophobic product was either 1% or 2%. The material layers were stacked before pressing to create multilayer materials with different levels of hydrophobic treatment on the inside and outside. The materials were pressed at 80–140°C using servo presses and screw-on cap or lid tools, depending on the desired geometry.

[0080] The table below summarizes the evaluated material composition. The numbers (0, 1, 2) represent the percentage of hydrophobic treatment in each layer.

[0081] [Table 3]

[0082] All materials performed adequately on both sides regarding the formation of 3D objects and water repellency. Changes in mechanical performance were observed depending on the type and amount of processing. This makes it possible to adjust the performance of the final product according to the needs and specifications.

[0083] The pressing process is highlighted in Figures 5 to 7. Figures 8 and 9 clearly show the results of the hydrophobic treatment described above, which makes the lids useful. The closure shown in Figure 10 was made in a form suitable for use in bottles such as those used for alcoholic beverages.

[0084] 4. Tests using materials containing various types of polymer fibers The multilayer materials were produced with all layers containing 5-10% (dry weight) of reinforcing polymer fibers. The fibers used were PHA, PHBH, cellulose acetate, PLA, and PE / PET. The bulky materials were pressed into screw-on caps at 140°C using a servo press equipped with the appropriate tools.

[0085] All materials produce perfectly molded closures with high rigidity, and in particular, PLA and PHA fibers result in well-formed, rigid 3D objects, demonstrating the strong potential use of these sustainable polymer fibers as mechanical reinforcement for pressed fiber materials.

[0086] 5. Lamination of biopolymer films Polymer films with a thickness of 20–150 μm were placed on top of bulky cellulosic multilayer materials using a screw-in cap tool before being pressed at 100–140°C in a servo press. The resulting pressed 3D objects contained high-density cellulose layers laminated without adhesive using the polymer film, providing barrier properties such as hydrophobicity, oleophobicity, gas barrier, and aroma barrier, depending on the inherent properties of the polymer film. The tested films included PHA, PLA, and PE films, all of which were obtained by pressing and laminating in a single operation, with the film positioned on one or both sides of the object (see Figure 11).

[0087] 6. Further testing using air raids The additional tests were conducted using a multilayer material (i.e., 250+700+250gsm) created by sandwiching an untreated 700gsm layer between two layers of the hydrophobic material described above. This multilayer material combines the high rigidity and high density of the untreated core cellulose material with the water-repellent properties of the treated outer layer, and may be a method for adjusting both the mechanical and water-repellent properties of a pressed object (see coffee lid in Figure 13).

[0088] While various embodiments of the present invention have been described above, those skilled in the art will recognize minor modifications that fall within the scope of the invention. The scope and scope of the invention should not be limited by any of the exemplary embodiments described above, but should be defined only by the following claims and their equivalents. For example, any of the above layer configurations or methods may be combined with other known methods. Other aspects, advantages, and modifications within the scope of the invention will be apparent to those skilled in the art who are familiar with the invention.

Claims

1. A multilayer substrate comprising at least one layer that provides tensile strength and one layer containing fibers having internal strength low enough to be formed by a press molding operation, wherein at least partially a new bond is formed at a new relative position.

2. The multilayer substrate according to claim 1, wherein at least one layer comprises pre-expanded microspheres and / or expandable microspheres.

3. The multilayer substrate according to claim 1, wherein at least one layer comprises a fiber mat produced by air-laid technology and / or a fiber mat produced by wet-laid technology.

4. The multilayer substrate according to claim 1, wherein at least one layer may include a paper sheet, preferably having a moisture content of about 4 to about 25%, most preferably about 7 to about 15%.

5. The multilayer substrate according to claim 1, wherein the layer providing the tensile strength provides a tensile strength at least about 10%, preferably at least about 20%, and most preferably at least about 50%, higher than the tensile strength of the other layers.

6. The multilayer substrate according to claim 1, wherein the substrate is made of at least three layers.

7. The multilayer substrate according to claim 6, wherein at least one of the layers of the at least three-layer material comprises at least one fossil-based and / or bio-based polymer and / or biodegradable polymer, such as PET or one or more polyolefins, and the biodegradable polymer is selected from the group comprising PLA, PHBH, PHA, and PEF, or combinations thereof.

8. The multilayer substrate according to claim 6, wherein the aforementioned high tensile strength is provided by at least one of the outer layers, and preferably the minimum tensile strength is about 75 N / m (CD).

9. The multilayer substrate according to claim 6, wherein the high tensile strength is provided by the two outer layers, and preferably the sum of the minimum tensile strengths is about 150 N / m (MD).

10. The multilayer substrate according to claim 6, wherein the layer(s) having high tensile strength is thinner than the central layer(s).

11. The multilayer substrate according to claim 1, 5, or 6, wherein the material has low initial tensile strength and provides one or more layers that are well repulped.

12. The multilayer substrate according to claim 6, wherein at least one of the outer layers preferably has high hydrophobicity and / or oleophobicity by using a water-repellent and / or oil-repellent agent such as alkyl ketene dimer, alkenyl succinic anhydride, or wax, or latex, or rosin, or bio-based fiber, or cellulose acetate, or a combination thereof.

13. The multilayer substrate according to claim 6, wherein at least one of the outer layers has high relative wet strength.

14. The multilayer substrate according to claim 6, wherein at least one of the outer layers has a high density.

15. The density is approximately 0.5 kg / dm³ ３ Lower than that, preferably about 0.1 to about 0.4 kg / dm ３ The multilayer substrate according to claim 1, 5, or 6.

16. The basis weight is approximately 100 to 2000 g / m². ２ Preferably about 300 to about 1500 g / m ２ The multilayer substrate according to claim 1, 5, or 6.

17. The multilayer substrate according to claim 1, 5, or 6, wherein the moisture content is about 4 to about 25%, preferably about 7 to about 15%.

18. The multilayer substrate according to claim 6, wherein at least one of the outer layers comprises one or more additives for extra strength and wet strength, and preferably, at least one component of the additive(s) comprises fibers of an artificial polymer.

19. A method for processing a multilayer substrate according to any one of the prior claims for providing a multilayer product, comprising the following steps: a) The step of providing the multilayer substrate, b) The step of exposing the substrate to high pressure, c) Providing a multilayer product by exposing the substrate to a high temperature, wherein optionally, pre-expanded microspheres and / or expandable microspheres are added, preferably before providing the multilayer substrate in step a), or simultaneously with providing the microspheres in step a), and most preferably before providing the multilayer substrate in step a), the microspheres are added to the multilayer substrate. Methods that include...

20. When at least one layer includes pre-inflated microspheres and / or inflatable microspheres, d) The multilayer substrate according to claim 19, wherein the multilayer substrate is provided to a mold assembly, and the material is heated to about 50 to about 150°C, preferably about 50 to about 120°C, most preferably about 60 to about 100°C, thereby providing a dry content of about 50 to about 70%, and consequently providing an expanded product or a foamed multilayer product.

21. The method according to claim 19, wherein steam is added in step d) to expand the multilayer substrate.

22. The method of claim 19, wherein the high pressure and high temperature of step b) and / or c) are provided by a press pad device and a stamping device.

23. The method according to claim 19, wherein the base material is made from chemothermetic pulp, thermomechanical pulp, kraft pulp, sulfate pulp, sulfite pulp, recycled pulp material, board or cardboard, or a combination thereof.

24. The method according to claim 19, wherein the base material is made from bleached pulp, unbleached pulp, or a combination thereof.

25. The method according to claim 19, wherein the base material is made from a hardwood or softwood, bagasse paper, algae or straw, or a combination thereof.

26. The method according to claim 19, wherein, prior to step a), a delivery step is performed which includes forming the substrate into a strip, and then folding the strip.

27. A multilayer product obtainable by the method described in any one of claims 19 to 26.

28. The multilayer product according to claim 27, wherein the product is a molded product such as a lid, screw cap, container, bread clip, or package, and the container may be a disposable cup, dairy product pack, autoclave package, or tray, or a plate for eating or storing food, or paper or cardboard such as foldable cardboard.

29. The multilayer product according to claim 27, wherein one of the outer layers is provided to form a thread or click-on function for sealable packaging such as a container, a closure, or part of a container or closure.

30. The method of using a multilayer product according to claim 27, wherein the product is part(s) of a molded product such as a lid, screw cap, container, bread clip, or package, and the container may be a disposable cup, dairy pack, autoclave package or tray, or a plate for eating or storing food, or paper or cardboard such as foldable cardboard.

31. A method for recycling a multilayer product according to any one of claims 26 to 28 for providing recycled pulp, comprising the following steps: i) Preferably, the steps include providing the multilayer product after use, ii) The step of immersing the product in a liquid, preferably water, most preferably warm water, iii) Optionally, the step of adding one or more decoupling agents to the liquid, iv) A step of providing recycled pulp by exposing the product to shear force in the liquid, Methods that include...

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