Oral pouch comprising a pouch shell made of a chemically bonded non-woven fabric and a filling material arranged therein

Abstract

Oral pouch comprising a pouch shell made of a chemically bonded nonwoven fabric containing cellulosic fibers, in the manufacture of which an additional crosslinking agent was added to the binder, which can form a covalent chemical bond with cellulose molecules, e.g., through ester or ether bonds, and a filling material arranged in the pouch shell.

Description

field of technology

[0001] The invention relates to an oral pouch comprising a pouch shell made of a cross-linked nonwoven fabric and a filling material arranged therein. Current state of the art

[0002] Oral pouches containing a typically moist tobacco mixture or a nicotine-containing substrate in a non-woven fabric pouch (oral tobacco pouches) are well-known. Snus is a form of oral tobacco particularly common in Scandinavia, made from dried, ground tobacco mixed with water, salt, and flavorings. Sometimes, a nicotine-containing substitute is used instead of tobacco, to which flavorings may be added. There are also oral pouches that contain a dry, often white, nicotine-containing substitute instead of moist tobacco. The snus pouch is placed behind the upper or lower lip. Within 15 to 60 minutes, it releases the tobacco flavor or added flavorings and nicotine. The released substances are absorbed by the body through the oral mucosa. The pouch is then removed from the mouth.

[0003] Also known are oral pouches for the administration of medications or stimulants or other active ingredients, such as caffeine or taurine, via the oral mucosa.

[0004] In oral pouches, such as those used for nicotine pouches, an interaction can occur between the active substances contained in the pouches (e.g., powders, granules, etc.) and the nonwoven fabric, which is detrimental to the functionality of the oral pouch. Depending on the composition of the substances, a sometimes significant decrease in the strength of the nonwoven fabric and the seal is observed in oral nicotine pouches. This effect is particularly noticeable with increasing moisture content of the powders and the use of strong flavors (e.g., wintergreen), and occurs especially in nonwovens cross-linked with binders (e.g., wetlaid or carded nonwovens bonded with binders). In addition to the loss of strength in the nonwoven fabric and seal, stickiness of the nonwoven fabric is sometimes observed with strong flavor powders that have a high moisture content (moist powder).

[0005] EP 4 070 671 A1 describes an oral pouch comprising a pouch shell made of a chemically bonded nonwoven fabric and a filling material containing nicotine and citric acid as flavoring agents. During oral use, the flavoring agent is released to produce a sour taste sensation. Technical task

[0006] The invention is based on the objective of providing a thermally sealable nonwoven fabric for an oral pouch and an oral pouch with a pouch cover made of a cross-linked nonwoven fabric and a filling material contained therein, the application properties of which, when used as a cover for an oral pouch, are less affected by the filling material of the pouch. Solution to the task

[0007] The object of the invention is achieved by a cross-linked nonwoven fabric according to claim 1 and by an oral pouch according to claim 11. Advantageous embodiments of the cross-linked nonwoven fabric and the oral pouch are specified in the dependent claims and in the following description. Advantageous effects of the invention

[0008] Investigations by the applicant have shown that the effect of loss of strength in the nonwoven fabric and seam, and the appearance of stickiness, is also observed in nonwovens that, in addition to the binder, use only fibers (e.g., cellulose, polypropylene) that are inert to the ingredients of "strong flavour" powders. Therefore, an interaction between the binder and the active ingredients contained in the strong flavour powders must be assumed. The described effect is largely reversible, so that the nonwovens mostly regain their strength if the nonwoven is left exposed to air and the active ingredients contained in the strong flavour, including water, are allowed to evaporate. Rinsing and drying the nonwoven also leads to a substantial restoration of its strength.Therefore, it can be assumed that the observed effect is not based on a chemical reaction, but on a physical effect in which active ingredients from the substances contained in the oral sachet penetrate the structure of the binder and cause swelling or act as plasticizers. Since the effect increases with increasing moisture content of the powder, it is conceivable that water molecules are involved in the mechanism of action.

[0009] According to the invention, during the production of the nonwoven fabric containing cellulosic fibers, citric acid, for example, is added as an additional crosslinking agent together with a (dispersion) binder to the fibers of a fiber layer. When the fiber layer is then transferred to a dryer, the citric acid can react with the cellulose molecules at the temperatures prevailing in the dryer, forming ester bonds and releasing water. By removing the water in the dryer, the reaction equilibrium shifts almost completely towards the ester compound.

[0010] Besides the formation of ester bonds to the cellulose molecules, other crosslinking agents are conceivable that can form a covalent bond to the cellulose molecule. Derivatives of epichlorohydrin (e.g., polyamidoamines epichlorohydrin (PAAE)) are examples of such agents, as they can form an ether bond to the cellulose molecule.

[0011] Citric acid is used in the paper industry as a crosslinking agent to increase the strength of paper. When increasing the wet strength of paper through crosslinking with citric acid, the effect is permanent (it does not disappear when the water evaporates) and is based on the crosslinking of the glycosidically linked glucose units of the cellulose and / or the citric acid via the formation of ester groups.

[0012] When citric acid is added to the (dispersion) binder during the production of a chemically binder-bonded nonwoven fabric containing a high proportion of cellulosic fibers, surprisingly, regardless of the binder used, the stickiness is eliminated or at least significantly reduced, and the influence of the crosslinking agent on the strength and sealing strength of the nonwoven fabric varies considerably. According to the invention, this is used to create a crosslinked nonwoven fabric for an oral pouch with at least significantly reduced stickiness and increased longitudinal strength and / or sealing strength when exposed to saliva containing active ingredients from the pouch's filling material.

[0013] The invention is explained in more detail below with reference to the accompanying drawings of exemplary embodiments. The drawings show: FIG. 1 a snus pouch according to the invention in front view; FIG. 2 the snus pouch from the back; FIG. 3a / b Longitudinal strength of the nonwoven fabric upon addition of citric acid to the vinacryl binder; FIG. 4 Seal strength of the nonwoven fabric when citric acid is added to the vinacryl binder; FIG. 5a / b Longitudinal strength of the nonwoven fabric upon addition of citric acid to the Plextol binder; FIG. 6 Seal strength of the nonwoven fabric when citric acid is added to the Plextol binder;

[0014] According to Figs. 1 and 2 A snus pouch 1 comprises a pouch 2 made of a nonwoven fabric 3, in which small quantities of tobacco material 4 and / or another nicotine-containing material or other active ingredient are arranged. The tobacco material 4 is, for example, snus. The nonwoven fabric 3 is made of a fiber mixture consisting of 80% viscose fibers and 20% PP fibers, bonded with a chemical binder.

[0015] The bag 2 is designed as a tubular bag. A strip of nonwoven fabric 3 is folded over at the long sides, and the long edges are joined together by a longitudinal heat-seal seam 5. Furthermore, the two transverse edges of the bag 2 are joined together by transverse heat-seal seams 6, 7.

[0016] When using snus, the pouch is placed behind the lower or upper lip. Saliva from the oral cavity enters and dissolves nicotine and other flavorings or active ingredients from the tobacco material or the substrate contained in the pouch. These substances are then absorbed by the body via the saliva through the oral mucosa.

[0017] The following test methods are used to determine the properties of the nonwovens according to the invention: NWSP 130.1.R0 (15) (area weight) (edana / inda) The test method for nonwovens according to DIN EN 29073-3 is used to determine the seal strength. The HS-2 test instrument from RDM Test Equipment Ltd., Unit 39, Golds Nurseries Business Park, Jenkins Drive, Elsenham, Herts. CM22, 6JX, England, was used to produce the sealed samples for the seal strength test. EDANA WSP 110.4 Longitudinal strength / transverse strength (dry or wet) in machine direction or transverse direction EDANA WSP 110.4 Elongation in machine (longitudinal) and transverse direction (dry or wet) To determine the stickiness of the different nonwovens, two layers of the nonwoven (15 cm x 15 cm) are placed on top of each other on a smooth surface and weighted with a rectangular steel weight (2 kg) measuring 15 cm x 15 cm for 5 minutes at 23 °C and a relative humidity of 50%.The nonwovens are then pulled apart by hand and comparatively assessed by the tester, who evaluates their relative stickiness. The test is conducted with at least four independent testers, comparing only two different nonwovens at a time. Example 1)

[0018] A fiber blend of 80% viscose fibers (0.9 dtex, 40 mm length) and 20% PP fibers (1.7 dtex, 40 mm length) with a basis weight of 17 g / m² is bonded to a nonwoven fabric with a basis weight of 34 g / m² using a dispersion binder (Vinacryl 4378 from Celanese) applied in a foam foil. The resulting nonwoven fabric has a basis weight of 50%. The tensile strength and seam strength of the resulting nonwoven fabric are measured in the machine direction (see the description of the test method for seam formation).

[0019] In a second experiment with the same fiber composition and binder content, 1 wt.% or 0.5 wt.% (based on the solids content of the binder) of citric acid is added to the binder before it is applied to the fibers in a foam foil and dried and cured in a drum dryer at 160 °C. Here too, the basis weight of the nonwoven fabric is 34 g / m².

[0020] The nonwoven fabric strength in the machine direction and the seal strength in the machine direction are measured on this nonwoven fabric treated with citric acid.

[0021] Both nonwoven samples (both the nonwoven specimen and the nonwoven specimen with a seal seam for determining seal strength) are then immersed in a nicotine powder with a strong flavoring (constituents in wt%: 5% xylitol, 63.6% MCC 200 (microcrystalline cellulose), 0.4% sucralose, 1% NaCl, 1.5% nicotine, 7.5% water, 13.5% glycerol, 7.45% wintergreen flavor HR.CNT007) in an airtight container at 23°C (these samples are subsequently referred to as "marinated" in the illustrations). After 5 days, the longitudinal strength and the longitudinal seal strength are determined. Table 1. Stickiness of the nonwoven fabric with / without the addition of citric acid to the vinacryl binder. Evaluation of the stickiness of the fleece (Vinacryl Binder) soaked in nicotine powder with added nicotine in a panel test (n=5): fleece less sticky sticks more even 0% citric acid 0 4 1 0.5% citric acid 4 0 1

[0022] Figure 1It can be seen that the addition of citric acid increases the longitudinal strength of the nonwoven fabric bonded with Vinacryl binder, both for untreated fabric and for fabric soaked in nicotine powder with added wintergreen. This could be explained by the citric acid cross-linking with the cellulose fibers (viscose) contained in the nonwoven fabric, forming ester bonds. This could also explain the observation that the nonwoven fabric produced with the addition of citric acid to the binder has reduced stickiness after being soaked in nicotine powder with added wintergreen.

[0023] Figure 2 It can be seen that the sealing strength of the nonwoven fabric bonded with Vinacryl is significantly reduced by the addition of citric acid to the binder. After treating the nonwoven fabric with the nicotine powder containing wintergreen, only a very slight increase in sealing strength due to the addition of citric acid is observed.

[0024] It appears that the citric acid reacts with the vinacryl binder, reducing its ability to form a stable seal. Since both the binder and the PP fibers contained in the nonwoven fabric contribute to the formation of the thermal seal, and PP is largely inert towards citric acid, it can be assumed that the citric acid reacts with the vinacryl polymer, reducing its thermal sealing capacity. This could occur through a crosslinking reaction that transforms the binder into a crosslinked structure with reduced thermoplastic properties, thus resulting in a weaker thermal seal.

[0025] The stickiness of the nonwoven fabric reinforced with Vinacryl is slightly reduced after exposure to nicotine powder containing wintergreen. This was determined in a haptic comparison test with five participants. The participants assessed the stickiness of nonwoven samples (nonwoven without citric acid and nonwoven with 0.5% citric acid) that had been soaked in nicotine powder containing wintergreen for five days. As shown in Table 1, four of the five participants rated the stickiness of the nonwoven fabric with 0.5% citric acid as slightly lower than that of the untreated fabric. One participant did not notice any difference in stickiness. Example 2:

[0026] A fiber blend of 80% viscose fibers (0.9 dtex, 40 mm length) and 20% PP fibers (1.7 dtex, 40 mm length) with a basis weight of 17 g / m² is bonded to a nonwoven fabric with a basis weight of 34 g / m² using a dispersion binder (Plextol B 500 from Synthomer) applied in a foam foil. The resulting nonwoven fabric has a solids content of 50%. The tensile strength and seam strength of the resulting nonwoven fabric are measured in the machine direction (see the description of the test method for seam formation).

[0027] In a second experiment with the same fiber composition and binder content, 1 wt.% or 0.5 wt.% (based on the solids content of the binder) of citric acid is added to the binder before it is applied to the fibers in a foam foil and dried and cured in a drum dryer at 170 °C. Here too, the basis weight of the nonwoven fabric is 34 g / m².

[0028] The nonwoven fabric strength in the machine direction and the seal strength in the machine direction are measured on this nonwoven fabric treated with citric acid.

[0029] Both nonwoven samples (both the nonwoven specimen and the nonwoven specimen with a seal seam for determining seal strength) are then immersed in a nicotine powder with a strong flavoring (constituents in wt%: 5% xylitol, 63.6% MCC 200 (microcrystalline cellulose), 0.4% sucralose, 1% NaCl, 1.5% nicotine, 7.5% water, 13.5% glycerol, 7.45% wintergreen flavor HR.CNT007) in an airtight container at 23°C (these samples are subsequently referred to as "marinated" in the illustrations). After 5 days, the longitudinal strength and the longitudinal seal strength are determined. Table 2. Stickiness of the nonwoven fabric with / without the addition of citric acid to the Plextol binder. Evaluation of the stickiness of the fleece (Plextol Binder) soaked in nicotine powder with added nicotine in the panel test (n=5): fleece less sticky sticks more even 0% citric acid 0 2 3 0.5% citric acid 2 0 3

[0030] Figure 3It can be seen that the addition of citric acid only slightly alters the longitudinal strength (dry or wet) of the fleece for the fleece not treated with nicotine powder containing wintergreen, but significantly increases it for the fleece immersed in nicotine powder with wintergreen, relative to the untreated fleece. The fleece produced with Plextol binder also shows the same effect: the fleece produced with the addition of citric acid to the binder has a significantly reduced stickiness after being immersed in nicotine powder with wintergreen for 5 days at 23 °C.

[0031] Figure 4 It can be seen that the sealing strength of the nonwoven fabric is significantly increased by the addition of citric acid to the Plextol B 500 binder, in contrast to the nonwoven fabric consolidated with Vinacryl binder.

[0032] After treating the fleece with the nicotine powder with wintergreen additive, it can be seen that the decrease in thermal sealing strength is significantly reduced by the addition of citric acid to the Plextol binder, so that a significantly higher thermal sealing strength can be observed with increasing proportion of added citric acid.

[0033] Unlike Vinacryl binder, the addition of citric acid to Plextol B 500 binder has no negative effect on its sealing properties. The two chemically similar binders (Vinacryl: a partially self-crosslinking mixture of vinyl acetate and butyl acrylate-based polymers / Plextol: a non-self-crosslinking thermoplastic acrylic polymer) differ primarily in that Vinacryl binder is partially self-crosslinking, while Plextol binder is non-self-crosslinking and consists of a dispersion of a thermoplastic acrylic polymer.The surprising difference in the behavior of the two binders with respect to the addition of citric acid to increase nonwoven strength and seal strength appears to be due to the fact that the self-crosslinking groups of the Vinacryl binder react with the citric acid and thus limit its ability to form a stable thermal seal, whereas the addition of citric acid to the Plextol binder does not lead to crosslinking of the binder, so that its thermal sealing ability is retained and the citric acid contributes to strengthening the nonwoven by reacting with the cellulose molecules.

[0034] The stickiness of the nonwoven fabric reinforced with Plextol is slightly reduced after exposure to nicotine powder containing wintergreen. This was determined in a haptic comparison test with five participants. The participants assessed the stickiness of nonwoven samples (nonwoven without citric acid and nonwoven with 0.5% citric acid) that had been soaked in nicotine powder containing wintergreen for three days. As shown in Table 2, two of the five participants rated the stickiness of the nonwoven fabric with 0.5% citric acid as slightly lower than that of the untreated fabric. Three participants did not notice any difference in stickiness.

Claims

1. Oral pouch comprising a pouch shell made of a chemically bonded nonwoven fabric containing cellulosic fibers, in the manufacture of which an additional crosslinking agent was added to the binder, which can form a covalent chemical bond with cellulose molecules, e.g. by ester or ether bonds, and a filling material arranged in the pouch shell.

2. Bag according to claim 1, wherein the added crosslinking agent is a divalent or higher carboxylic acid such as citric acid, adipic acid, tartaric acid, maleic acid or succinic acid.

3. Bags according to claims 1 to 2, wherein the polyhydric carboxylic acid used as a crosslinking agent additionally contains at least one alcohol group such as citric acid.

4. Bag according to claim 1, wherein the crosslinking agent used belongs to the class of amino acids.

5. Bag according to claim 1, wherein the crosslinking agent used belongs to the class of epichlorohydrin derivatives, e.g. polyaminoamide epichlorohydrins (PAE).

6. Bag according to any one of claims 1 to 5, wherein the nonwoven fabric, after storage for at least 5 days at 30 °C in a powder mixture of (percentages by weight): 5% xylitol, 63.6% MCC 200 (microcrystalline cellulose), 0.4% sucralose, 1% NaCl, 1.5% nicotine, 7.5% water, 13.5% glycerol, 7.45% wintergreen flavor HR.CNT007, has a seal strength of at least 2 N / 5cm, preferably 4 N / 5cm.

7. Bag according to any one of claims 1 to 6, wherein the nonwoven fabric, after storage for at least 5 days at 30 °C in a mixture of (percentages by weight): 5% xylitol, 63.6% MCC 200 (microcrystalline cellulose), 0.4% sucralose, 1% NaCl, 1.5% nicotine, 7.5% water, 13.5% glycerol, 7.45% wintergreen flavor HR.CNT007, has a longitudinal strength of at least 10 N / 5cm, preferably at least 20 N / 5cm and particularly preferably at least 30 N / 5cm.

8. Bag according to any one of claims 1 to 7, wherein the nonwoven fabric, after being stored for at least 5 days at 25 °C in a mixture of (percentages by weight): 5% xylitol, 63.6% MCC 200 (microcrystalline cellulose), 0.4% sucralose, 1% NaCl, 1.5% nicotine, 7.5% water, 13.5% glycerol, 7.45% wintergreen flavor HR.CNT007, in a comparative haptic evaluation by at least 5 testers, at least 70% of the testers rated the bag produced with the additional crosslinking agent as less sticky than the bag produced without the additional crosslinking agent.

9. Bag according to any one of claims 1 to 8, wherein the binder is a partially self-crosslinking mixture of polymers based on vinyl acetate and butyl acrylate and the nonwoven fabric has a proportion of thermoplastic fibers which provides a sealing strength of at least 2 N / 50mm, preferably at least 4 N / 50mm.

10. Bag according to any one of claims 1 to 9, wherein the binder is a non-self-crosslinking thermoplastic acrylic polymer.

11. Pouch according to any one of claims 1 to 10, wherein the filling material comprises at least one of the following materials or substances: (i) a tobacco material or other plant material, (ii) another nicotine-containing material, (iii) a nicotine replacement substance, (iv) a drug or other active ingredient, (v) a food supplement, (vi) a stimulant, (vii) a flavoring, (viii) a flavoring, (ix) a coloring, or (x) a carrier material loaded with an active ingredient.

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