Nonwoven fabric for oral pouch products and method of manufacturing a

Abstract

The present invention relates to non-woven fabrics for oral pouch products and methods of making non-woven fabrics. The present invention provides a nonwoven fabric for use as a package in an oral pouch product wherein the nonwoven fabric comprises a web of chemically bonded staple fibers wherein the relative proportions of staple fibers and binder are selected in conjunction with the density of the fabric to achieve an optimal balance, thereby achieving a fabric comprising a web of chemically bonded staple fibers and a web of chemically bonded staple fibers. The present invention relates to an oral product which provides a soft (e.g., low friction) mouthfeel, has a wet strength that can withstand operations (e.g., chewing, sucking, etc.) in the mouth of a user, and prevents the occurrence of accidental leaching or leakage of flavors or other fine particulate matter used in modern oral products.

Description

[0001] This application is a divisional application of Chinese patent application No. 202280010789.1 (PCT / EP2022 / 052411), filed on February 2, 2022, entitled "Nonwoven fabric for oral pouch products and method of manufacturing nonwoven fabric". Technical Field

[0002] This invention relates to a nonwoven fabric for manufacturing oral pouch products. In particular, this invention relates to a nonwoven fabric with enhanced strength and stability for use in modern oral products. Background Technology

[0003] It is known to use such nonwoven fabrics to manufacture bags for containing single-serving products, such as smokeless tobacco (also known as "snuff"), coffee, tea, etc., from which flavors are extracted. Examples of bagged products formed from nonwoven fabrics are provided in US 2014 / 0026912A1 and US 2012 / 0103353 A1.

[0004] For years, nonwoven fabrics have been used to produce pouches for traditional smokeless tobacco products, such as snuff. Recently, the market for this type of oral pouch product has expanded to include so-called “modern oral” products, where the pouch contents can contain a wide variety of materials, such as non-tobacco nicotine, flavorings, and / or other food-grade products.

[0005] Nonwoven fabrics are typically produced using one of three processes: dry web forming, wet web forming, or melt spinning. Each process involves winding fibers or filaments into a web without weaving or knitting.

[0006] Dry web forming processes typically involve forming a loose web of short fibers, which are then bonded together to form a fabric. The web can be formed using an air-laid process, whereby the fibers are randomly oriented within the web. Alternatively, web formation may include carding the fibers, which aligns their orientation. Air-laid or integrated webs can be bonded using mechanical techniques (e.g., hydroentangling or needle punching), thermal techniques (e.g., in cases where the web comprises thermoplastic fibers), or chemical techniques (e.g., using adhesives) or combinations thereof.

[0007] The wet web forming process typically involves forming a fiber slurry in water or other suitable liquid, depositing the slurry onto a screen or mesh, and then drying it to form a web.

[0008] Spunmelt processes typically use continuous filaments spun directly from liquid (i.e., molten) plastic materials to form webs.

[0009] One known type of nonwoven fabric used in bagged products is a dry-carded nonwoven fabric, which comprises short fibers formed from regenerated cellulose (also known as viscose or rayon) and a thermoplastic acrylic copolymer binder, the binder promoting the fabric's heat-sealing ability and providing a soft feel.

[0010] Typically, nonwoven fabrics used in the production of bagged products are water-permeable to allow substances from the bag's contents (e.g., condiments) to leak out.

[0011] Nonwoven fabrics can be used to manufacture chewable bags. For example, US2018 / 0153211 A1 discloses a nonwoven fabric for manufacturing bagged products, wherein the bag comprises an elastic mesh of thermoplastic polyamide that ensures the bag can withstand repeated deformation caused by chewing. The elastic mesh in this example has a high percentage of open area (i.e., high porosity) to achieve a rapid rate of flavor release from the bag.

[0012] US2013 / 0149254 A1 discloses a perforated chewable pouch made of a food-grade material selected from silicone, latex, rubber, or plastic. The pouch encapsulates a product that may be in gel, semi-liquid, or liquid form. The user chews, sucks, and / or manipulates the pouch to allow the encapsulated flavored product to seep from the perforations into the user's mouth.

[0013] US2014 / 0261480 A1 discloses a bag formed from a fabric comprising meltblown polymer fibers having a hydrophilic surface coating. The meltblown material may be an elastomer (e.g., polymeric polyurethane), making the bag resistant to chewing.

[0014] The appearance and taste of oral pouch products are very important. Short fibers used in the manufacture of nonwoven fabrics can play a significant role here. For example, DE 20 2015 102 564 U1 discloses an oral pouch made from a fabric containing lyocell fibers commercially available from Lenzing AG. This document discloses that using lyocell short fibers can make the pouch more translucent and can also improve the transition of nicotine and flavor.

[0015] Similarly, EP 3 192 380 A1 discloses an oral pouch product for containing a portion of snuff, wherein the pouch is formed of a dry-laid nonwoven material, wherein at least 50% of the short fibers are lyocell fibers, and wherein the dry-laid nonwoven material has a density of up to 25 g / m³. 2 The document discloses that these properties can produce a bag with improved transparency and reduced tendency to fade during storage. Summary of the Invention

[0016] Most generally, the present invention provides a nonwoven fabric for manufacturing oral pouch products, wherein the nonwoven fabric comprises a web of chemically bonded short fibers, wherein the relative proportions of the short fibers and the binder are selected in conjunction with the density of the fabric to achieve an optimal balance, thereby realizing a fabric that provides a soft (e.g., low-friction) mouthfeel, has wet strength capable of withstanding user mouth handling (e.g., chewing, sucking, etc.), and prevents accidental leaching or leakage of flavorings or other fine particulate matter used in modern oral products.

[0017] The short fibers may be formed from regenerated cellulose (viscose) or other conventional materials. In a preferred embodiment, the short fibers in the nonwoven fabric may be non-viscose. For example, the short fibers may comprise or consist of lyocell fibers with selected properties to provide strength and stability particularly suitable for the types of tobacco-free substances used in modern oral products.

[0018] In some instances, the use of biodegradable short fibers (such as lyocell fibers) in conjunction with biodegradable binders (such as polylactic acid) may be particularly advantageous. The resulting nonwoven fabrics can be fully compostable and can be manufactured sustainably.

[0019] Bags made from the nonwoven fabric of this invention can be used to encapsulate any suitable material with the aim of extracting flavorings, nutrients, or any other chemicals from that material, for example, for oral delivery. The contents of the bag may contain smokeless tobacco, non-smoking nicotine, pharmaceuticals, coffee, tea, or a combination thereof.

[0020] According to a first aspect of the invention, a nonwoven fabric for forming oral pouch products is provided, the nonwoven fabric comprising a chemically bonded web of short fibers, wherein the short fibers comprise lyocell fibers, and wherein the nonwoven fabric has a density greater than 25 g / m². 2 The base weight.

[0021] In this article, "chemical bonding" can refer to a short fiber matrix that is fixed together by bonding, that is, by an adhesive used to physically interconnect short fibers.

[0022] The web can be composed of multiple carded short fiber layers. Combining multiple carded layers into an integrated web can help achieve uniformity within the fabric and improve its strength.

[0023] In this application, the staple fibers may consist substantially of sustainably manufactured regenerated cellulose, such as lyocell fiber. The nonwoven fabric is viscose-free. In the examples discussed herein, lyocell fiber is preferably the primary material and may constitute 100% of the staple fibers. In other examples, the staple fibers may contain or be composed of other biodegradable, compostable, or sustainably manufactured materials. For example, the staple fibers may include materials such as polylactic acid (PLA), polyvinyl alcohol (PVOH), polybutylene succinate (PBS), bamboo, and natural bast fibers (such as hemp, ramie, jute, flax, kenaf, and nettle).

[0024] The short fibers may have properties selected according to the process of forming the integrated web. For example, the short fibers may have a fiber density in the range of 0.9 to 4.4 dtex, preferably 0.9 to 2.2 dtex.

[0025] The basis weight is greater than 25 g / m 2 Lyocell-based fabrics offer enhanced tolerance to natural or synthetic flavorings found in modern oral products. These flavorings typically have a smaller particle size than the tobacco-based substances commonly used in smokeless tobacco pouches. Lower basis weight fabrics can have a more open structure, allowing the fine particles to pass through easily and thus lose flavor more readily.

[0026] A balance may need to be struck between resistance to flavor leakage in the dry state and the ability to release flavor in an aqueous environment. The proposed lyocell-based fabric exhibits enhanced wet strength, which allows it to be manipulated in aqueous environments, such as through chewing, biting, or sucking. This can aid in flavor release. To achieve the necessary balance, the basis weight can be less than or equal to 40 g / m³. 2 .

[0027] Fabric density can also contribute to the strength of nonwoven fabrics. As used herein, “fabric density” can refer to the basis weight of the fabric divided by its thickness. In some examples, the nonwoven fabric may have a fabric density in the range of 140 g / mm to 170 g / mm, preferably 150 g / mm to 160 g / mm.

[0028] The nonwoven fabric may contain an adhesive. Examples include synthetic acrylic adhesives, polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxyalkanoates (PHA), vinyl acetate copolymers, vinyl acrylate copolymers, and styrene-butadiene copolymers. The adhesive may be present in the nonwoven fabric at a concentration between 30 wt% and 50 wt% based on the dry weight of the nonwoven fabric. The adhesive is preferably selected from biodegradable or bioconvertible materials.

[0029] The nonwoven fabric is preferably heat-sealable. Here, heat-sealable can refer to the ability to form a physical bond with itself when heat is applied. Heat can be applied in conjunction with pressure, for example, at a specific location (sealing line) on the nonwoven fabric. This property allows oral pouch products formed from this material to be sealed using known heat-sealing techniques. The heat-sealable property can be provided by an adhesive integrated into the nonwoven fabric substrate.

[0030] The nonwoven fabric can be used to manufacture oral pouch products, i.e., pouches formed from the aforementioned nonwoven fabric, wherein the pouch encapsulates a substance containing a carrier medium of nicotine and flavoring.

[0031] According to a second aspect of the invention, a method for manufacturing a nonwoven fabric for forming oral pouch products is provided, the method comprising: forming an integrated web by combining a plurality of short fiber layers; and applying an adhesive to the integrated web to bond the short fibers together in the nonwoven fabric, wherein the short fibers comprise lyocell fibers, and wherein the nonwoven fabric has a density greater than 25 g / m². 2 The basis weight. The step of combining multiple carded layers of lyocell fibers into an integrated web can help achieve uniformity within the fabric and improve its strength. This combining step can be performed by pulling the layers together before applying an adhesive, for example, by covering the layers onto rollers, etc.

[0032] The characteristics of the first aspect discussed above can also be applied to the second aspect.

[0033] The step of applying the adhesive may include: impregnating the integrated web with an adhesive solution; and drying the impregnated integrated web to form the nonwoven fabric. For example, the adhesive may be applied by impregnation, spraying, or the like.

[0034] The air permeability of the nonwoven fabric can be equal to or greater than 1700 l / m 2 / s, more preferably equal to or greater than 2500 l / m 2 / s. A permeability higher than this threshold can promote the formation of bagged products by allowing air to escape at an appropriate rate when the contents of the bag are sealed. Attached Figure Description

[0035] Embodiments of the invention will now be discussed in more detail with reference to the accompanying drawings, in which:

[0036] Figure 1 This is a schematic diagram of an apparatus for manufacturing nonwoven fabrics according to a method as an embodiment of the present invention.

[0037] Detailed implementation methods; more options and preferences

[0038] Now refer to Figure 1Describe a method for manufacturing nonwoven fabrics based on this example. Figure 1 This is a schematic diagram illustrating an apparatus 100 for manufacturing dry-laid combed nonwoven fabrics. However, it should be understood that the present invention is not limited to this type of manufacturing technique.

[0039] exist Figure 1 In the illustrated apparatus 100, a first conveyor 102 transports fiber bundles 104 to a debundler 106, which separates and blends the fibers from the individual bundles. Any suitable cellulose-based short fiber (e.g., viscose) can be used. However, in a preferred arrangement, fiber bundles 104 may comprise non-viscose short fibers. Lyocell fibers are used in the examples below. In some instances, lyocell fibers may be combined with other types of short fibers, particularly other biodegradable fibers.

[0040] Lyocell fiber is a form of regenerated cellulose, obtained, for example, by directly and physically dissolving wood pulp using a non-toxic solvent (such as an amine oxide solution). Examples of lyocell fiber can be found under the trade name... Purchased from Lenzing AG. Lyocell fibers can be manufactured sustainably using a essentially closed-loop process in which the solvents and water used for dissolution are completely recycled. In this example, the short fibers are 100% lyocell.

[0041] Lyocell fiber is ideally suited for use, not only for the aforementioned sustainability reasons, but also because it provides the resulting fabric with desirable texture and wet strength. Lyocell fiber typically has a higher degree of cellulose crystallinity compared to viscose fiber of the same size. This gives lyocell fiber a fibrillary structure. This invention utilizes this property to provide nonwoven fabrics with improved stability for use with substances contained in modern oral products. For example, the nonwoven fabric can exhibit reduced absorption of micron-sized material types (e.g., certain types of flavorings) that can be used in modern oral products as substitutes for tobacco-based substances. Therefore, the nonwoven fabric can facilitate the transfer of microparticles along with contents such as nicotine and flavorings from the pouch.

[0042] The short fibers in fiber bundle 104 can have any suitable cross-section. In some instances, the short fibers consist of or contain multi-lobed fibers (e.g., fibers exhibiting a cross-section containing three or more lobes). Multi-lobed fibers can further facilitate the transfer of micron-sized materials through the nonwoven fabric.

[0043] Unpacking machine 106 is connected to feed hopper 108, which discharges the blended fibers as a loose fiber web 112 onto second conveyor 110. The loose fiber web 112 is conveyed to carding machine 114, which cardes the web to apply one or more desired orientations to the fibers. Therefore, carding machine 114 outputs a consolidated web 116 onto third conveyor 118.

[0044] In some instances, the integrated web 116 may include multiple carded layers. Each carded layer may be output from its respective carding machine 114 before being combined with other carded layers into a single integrated web. The multiple carded layers can be obtained by splitting the loose fiber web 112 between the respective carding machines. Providing multiple carded layers can improve the uniformity of the integrated web.

[0045] The combing process can be optional. For example, the integrated web 116 can be formed directly by air-laying suitable lyocell fibers. In this example, the lyocell fibers can be crimped during manufacturing to promote the formation of the fiber web in the airflow. Alternatively, the integrated web 116 can be formed directly by a wet-laying process.

[0046] The fibers in the integrated mesh 116 can then be bonded together using any conventional method. For example, an adhesive can be applied to the integrated mesh, such as by using a deflector 134 to deliver the adhesive to a disc 136 containing liquid adhesive or an adhesive precursor, so that the adhesive impregnates or saturates the integrated mesh 116. The integrated mesh 116 is then conveyed via rollers 138 to a fourth conveyor 120, which operates to remove or squeeze out excess liquid from the integrated mesh 116. The mesh 116 is then conveyed through a dryer 122, which operates to dry the mesh and cure or stabilize the adhesive. In other instances, the adhesive can be applied by coating or spraying.

[0047] The adhesive can be applied in the form of an aqueous solution, in which the water is subsequently removed by a drying process. However, other solvents can also be used.

[0048] It may be desirable for the adhesive or adhesive precursor to release no or negligible amounts of volatile organic compounds (VOCs).

[0049] In some instances, the final nonwoven fabric may be fully biodegradable. In this case, the binder may be biodegradable or bioconvertible. Examples of biodegradable binders include polylactic acid (PLA), polybutylene succinate (PBS), and polyhydroxyalkanoates (PHA) in any combination. In other instances, the binder may include additives capable of promoting the bioconversion of any plastic in the fabric composition. For example, a bioconversion masterbatch of the type manufactured by Polymateria Limited may be added to the integrated web, for example, in an amount equal to or less than 2 wt% of the dry weight of the resulting nonwoven fabric.

[0050] Other additives can be added to the integrated fabric. For example, triglyceride additives can be used to further improve the wet strength of the resulting fabric. The presence of triglycerides in nonwoven fabrics can also help prevent the accidental leakage of flavor particles from the contents of oral pouch products made using this fabric.

[0051] The process was configured such that the resulting bonded web 124 had a g / m² content greater than 25 g / m³. 2 For example, greater than 30g / m2, up to 35g / m 2 Or even 40g / m 2 The basis weight. Lyocell-based nonwoven fabrics with lower basis weights can provide structures that are too open for the types of substances used in many modern oral products. For example, many modern non-tobacco oral products may contain materials with fine particles (e.g., having dimensions smaller than or on the micrometer scale), which may pass through the fabric network more easily compared to more conventionally large-sized substances. This basis weight is typically achieved by selecting the relative ratio of binder to the fiber matrix and by controlling the rate at which the fiber web is laid on the conveyor. For example, the binder in the resulting bonded web 124 can be up to 50 wt%. The binder can be present in the final nonwoven fabric in a range between 30 wt% and 50 wt% of the dry weight of the nonwoven fabric.

[0052] The basis weight of the resulting bonding web 124 can be selected in conjunction with its thickness to provide a material with the desired fabric density. Fabric density affects the air permeability and liquid permeability of the material. Air permeability is important if the fabric is subsequently used in a pouching process, i.e., to form an encapsulation for oral delivery of substances. Liquid permeability plays a significant role in the fabric's ability to release substances into the user's mouth. Fabric density also affects the strength of the fabric. The inventors have discovered that selecting a fabric density in the range of 140 g / mm to 170 g / mm, and preferably in the range of 150 g / mm to 160 g / mm, achieves an optimal balance of these factors.

[0053] Table 1 summarizes the desired composition and properties of the nonwoven fabrics used as embodiments of the present invention.

[0054]

[0055] Table 1 Fabric composition and properties

[0056] The above properties of a given material sample can be tested using conventional techniques. For example, the basis weight test result can be obtained using the NWSP130.1.R0EDANA test method. The fabric thickness can be obtained using the NWSP120.6.R0EDANA test method, and therefore the fabric density can be measured by dividing the fabric weight by the fabric thickness.

[0057] Surface roughness provides a measurable parameter indicating taste. Surface roughness can be measured using an industry-standard surface roughness tester, such as the SurfTest SJ-210. Wet strength can be measured using the 20.2-89 EDANA test method. Air permeability can be obtained using the 070.1.R3(12) EDANA test method.

[0058] The final characteristics relate to testing whether the fabric can form a bag with the required sealing strength for oral pouch products. These test results can be obtained using CORESTA Recommended Method 90 on heat-sealed bags formed from the relevant fabric.

[0059] Table 2 shows three example fabric compositions as embodiments of the present invention. The composition of the fabric is selected to provide an optimized combination of weight and density, thereby producing the ideal strength, mouthfeel, permeability, and heat-sealability required for materials forming oral pouch products. The third example is a fully biodegradable material.

[0060]

[0061] Table 2 Specific Implementation Examples

[0062] The features disclosed in the foregoing description or the appended claims or drawings, in their specific form or expressed according to the means for performing the disclosed functions or according to the methods or processes for obtaining the disclosed results, may, where appropriate, be used alone or in any combination of the said features to implement the invention in various forms.

[0063] While the invention has been described in conjunction with the exemplary embodiments described above, those skilled in the art will recognize many equivalent modifications and variations based on this disclosure. Therefore, the exemplary embodiments of the invention set forth above are to be considered illustrative rather than restrictive. Various changes may be made to the described embodiments without departing from the spirit and scope of the invention.

[0064] To avoid any ambiguity, any theoretical explanations provided herein are intended to enhance the reader's understanding. The inventor does not wish to be bound by any of these theoretical explanations.

[0065] Any section headings used in this article are for organizational purposes only and should not be construed as limiting the subject matter described.

[0066] Throughout the specification including the appended claims, unless the context otherwise requires, the words “comprise” and “include”, as well as variations such as “comprises / comprising” and “including”, shall be understood to implicitly include the indicated integer or step or group of steps, but do not exclude any other integer or step or group of steps.

[0067] It must be noted that, unless the context explicitly indicates otherwise, the singular forms “a / an” and “the” as used in this specification and the appended claims include a plural of the referred objects. A range may be expressed herein as from “about” a particular value and / or to “about” another particular value. When such a range is expressed, another embodiment includes from said one particular value and / or to said other particular value. Similarly, when a value is expressed as an approximation using the antecedent “about”, it will be understood that said particular value forms another embodiment. The term “about” in relation to numerical values ​​is optional and means, for example, + / - 10%.

Claims

1. A nonwoven fabric for manufacturing oral pouch products, said nonwoven fabric comprising a web of chemically bonded short fibers and an adhesive; The basis weight of the nonwoven fabric is greater than 25 g / m². 2 , The adhesive is said to be biodegradable or biotransformable; and The adhesive is present in the nonwoven fabric in an amount less than or equal to 50 wt% based on the resulting bonded web.

2. The nonwoven fabric of claim 1, wherein the short fibers comprise cellulose-based fibers and do not include viscose fibers.

3. The nonwoven fabric according to any one of the preceding claims, wherein the short fibers comprise lyocell fibers.

4. The nonwoven fabric of claim 3, wherein the short fibers comprise a combination of lyocell fibers and other biodegradable fibers.

5. The nonwoven fabric according to claim 3, wherein the short fibers are composed of lyocell fibers.

6. The nonwoven fabric according to any one of the preceding claims, wherein the fiber density of the short fibers is in the range of 0.9 to 2.2 dtex.

7. The nonwoven fabric according to any one of the preceding claims, wherein the adhesive comprises one or more compounds selected from the group consisting of: Polylactic acid; Polybutylene succinate; and Polyhydroxyalkanoate.

8. The nonwoven fabric according to any one of claims 1 to 6, wherein the binder comprises an additive capable of promoting the bioconversion of any plastic in the fabric composition.

9. The nonwoven fabric according to any one of the preceding claims, wherein the web comprises a plurality of carded short fiber layers.

10. The nonwoven fabric according to any one of the preceding claims, wherein the web comprises air-laid lyocell fibers.

11. The nonwoven fabric according to any one of the preceding claims, wherein the basis weight is less than or equal to 40 g / m². 2 .

12. An oral pouch product formed from a nonwoven fabric according to any one of the preceding claims.

13. A method for manufacturing a nonwoven fabric suitable for forming oral pouch products, the method comprising: An integrated network is formed by combining multiple short fiber layers; as well as An adhesive is applied to the integrated web to bond the short fibers together in the nonwoven fabric. The basis weight of the nonwoven fabric is greater than 25 g / m². 2 , The adhesive is said to be biodegradable or biotransformable; and The adhesive is present in the nonwoven fabric in an amount less than or equal to 50 wt% based on the resulting bonded web.

14. The method of claim 13, wherein the adhesive is applied in the form of an aqueous solution.

15. The method according to claim 13 or 14, wherein the short fiber comprises lyocell fiber.

Images