Sanitary product

Abstract

A sanitary product including an absorbent material comprising a frictionally self- supporting fibrous network of hemp fibres and another natural fibrous material, wherein the length of a majority of said fibres is 20mm or more.

Description

[0001] SANITARY PRODUCT

[0002] Field of the Invention

[0003] This invention relates generally to a sanitary product, for example, a tampon or a sanitary towel designed to absorb blood and vaginal secretions, in use.

[0004] Background of the Invention

[0005] Tampons are well known and widely used to absorb blood and vaginal secretions by insertion thereof into the vagina of a user, usually during menstruation. A tampon typically comprises an elongate body of generally circular cross-section, rounded at one end and provided with a string (or similar element) affixed to, and extending from, the rounded opposite end. The body of the tampon would typically comprise a compressed, absorbent material, that expands within the vagina, during use, as fluids are absorbed thereby. In use, a tampon is inserted manually (often with the help of an applicator), via the rounded end, into the vagina, leaving the string accessible externally so that the user can pull the tampon back out of the vagina as and when required. As stated above, the tampon body is typically formed of a compressed absorbent material, such as organic cotton (sometimes mixed with other fibres), although other materials, such as rayon, polyester, polyethylene and polypropylene, and / or mixtures of such materials are often used in some such products.

[0006] The main problem with many, if not all tampon products currently available is that they are not fully or readily biodegradable, and / or involve a manufacturing process that is not eco-friendly. In the current environment, this is clearly undesirable. Even solutions claiming to be eco-friendly have significant disadvantages, including poor processability of main ingredients leading to high fibre loss and / or fibre yield before, during or after processing, web integrity (e.g. break rate during processing), poor surface texture (i.e. surface roughness (determined via profilometry or friction coefficient) of the tampons and poor absorbency. Indeed, the absorbency (determined by syngina testing for tampons and absorbent capacity for sanitary towels) of some of the material used is not always sufficient, especially for heavy flows. Still further, the carbon footprint of many known products is relatively high due to the manufacturing processes used. It is highly desirable to provide a solution using low-carbon raw materials and / or the use of renewable energy during processing.

[0007] Sanitary towels are well known and widely used to absorb blood and vaginal secretions, usually during menstruation. A sanitary towel typically comprises an elongate pad of absorbent material, shaped and configured to be placed and held over the inner surface of the gusset of a user’s undergarment. In some cases, the pad is held in place by a strip of adhesive material on the rear of the pad that allows it to simply be adhered to the inner surface of the gusset of the user’s undergarment. In other cases, however, this function is achieved by means of a pair of “wings”, one on each elongate side edge of the pad, and designed to be folded over the respective side edges of the gusset to be adhered to the outer surface of the gusset to hold the pad in place. The pad is typically formed of a compressed absorbent material, such as organic cotton (sometimes mixed with other fibres), although other material, such as rayon, polyester, polyethylene and polypropylene, and / or mixtures of such materials, are often used in some such products.

[0008] The main problem with many, if not all, sanitary towel products currently available is that they are not fully or readily biodegradable, and / or involve a manufacturing process that is not eco-friendly. In the current environment, this is clearly undesirable. Furthermore, the absorbency of some of the materials used is not always sufficient, especially for heavy flows.

[0009] Accordingly, aspects of the invention seek to address one or more of these issues.

[0010] Statements of the Invention

[0011] According to a first aspect of the invention, there is provided A sanitary product including an absorbent material comprising a porous, liquid permeable, frictionally self-supporting fibrous network of hemp fibres and another natural (which includes bio-derived) fibrous material, wherein the length of a majority of said fibres is 20mm or more.

[0012] According to a second aspect of the invention, there is provided a tampon as defined in claim 1 of the appended claims. Some optional and preferred aspects and variables are set out in the associated dependent claims. According to a third aspect of the invention, there is provided a sanitary towel as defined in claim 19 of the appended claims. Some optional and preferred aspects and variables are set out in the associated dependent claims.

[0013] These and other aspects and optional features of the invention will be apparent from the following detailed description.

[0014] Brief Description of the Drawings

[0015] Figure 1 is a schematic perspective view of a tampon according to an exemplary embodiment of the invention;

[0016] Figure 2 is a schematic perspective view of a veiled tampon according to an exemplary embodiment of the invention;

[0017] Figure 3 is a schematic perspective view of a non-veiled tampon according to an exemplary embodiment of the invention;

[0018] Figure 4 is a schematic longitudinal cross-section of a tampon ribbon for use in manufacturing a tampon according to an exemplary embodiment of the present invention;

[0019] Figure 5 is a schematic diagram illustrating a first part of a manufacturing process for a tampon according to an exemplary embodiment of the invention;

[0020] Figure 5A is illustrative of a ribbon roll process used in a manufacturing process for a tampon according to an exemplary embodiment of the present invention;

[0021] Figure 6 is a schematic front view of a tampon according to a first exemplary embodiment of the present invention;

[0022] Figure 7 is a schematic plan view of a tampon ribbon for use in manufacturing a tampon according to a second exemplary embodiment of the present invention;

[0023] Figure 8 is a schematic diagram illustrating a first part of a manufacturing process for a tampon according to an exemplary embodiment of the invention;

[0024] Figure 8A is illustrative of a ribbon roll process used in a manufacturing process for a tampon according to an exemplary embodiment of the present invention; Figure 9 is a schematic front view of a tampon according to a second exemplary embodiment of the present invention;

[0025] Figure 10 is a scanning electron microscopy partial cross-sectional image of a duallayered material suitable for use in a tampon according to an exemplary embodiment of the invention;

[0026] Figure 11 is a schematic perspective view of a sanitary towel according to an exemplary embodiment of the invention;

[0027] Figure 12 is a schematic side cross-sectional view of a sanitary towel according to a first exemplary embodiment of the invention;

[0028] Figure 13 is scanning electron microscopy image of a carded core material suitable for use in an example sanitary towel, the material comprising cottonised hemp and organic cotton fibres in a frictional ly self-supporting fibrous network;

[0029] Figure 14 is a schematic plan view of a sheet of cotton spunlace forming, in use, a core wrap of a sanitary towel according to an exemplary embodiment of the present invention;

[0030] Figure 15 is a schematic side cross-sectional view of the spunlace core wrap and core of a sanitary towel according to an exemplary embodiment of the invention;

[0031] Figure 15A is a schematic plan view of the spunlace core wrap and core of the sanitary towel of Figure 15;

[0032] Figure 16 is a schematic side cross-sectional view of a sanitary towel according to an exemplary embodiment of the invention; and

[0033] Figure 16A is a schematic plan view of the sanitary towel of Figure 16.

[0034] Detailed Description

[0035] In the following description of various exemplary embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which are shown, by way of examples and illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that variations and modifications may be made, without departing from the scope of the invention as defined in the appended claims. The following detailed description is therefore not to be taken in a limited sense.

[0036] The specification may refer to “an”, “one” or “some” embodiment(s) in some parts. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature applies to only one embodiment. Single features of different embodiments may also be combined to make another embodiment.

[0037] As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and / or “comprising”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, operations, steps, elements, components and / or groups thereof As used herein, the term “and / or” includes any and all combinations and arrangements of one or more of the associated listed items.

[0038] Directional descriptors such as upper, lower, left, right, clockwise, anti-clockwise, front, rear and other similar adjectives are used for clarity and refer to the orientation of the invention as illustrated in the drawings, however it will be clear to those skilled in the art that the invention may not always be oriented as illustrated and the invention is not intended to be limited in this regard.

[0039] Referring to Figure 1 of the drawings, an exemplary embodiment of the invention comprises a tampon 10 comprising an elongate, generally cylindrical body 12 of compressed, absorbent material, rounded at one end 14, and having a string 16 (or similar device) attached at, and extending externally of, the opposite end. The body 12 is of a generally circular cross-section and appears, externally, similar in many respects to a conventional tampon. However, it is an object of at least some exemplary embodiments of the invention to provide such a tampon that is a fully and readily biodegradable and free of any plastic fibres, with a reduced carbon footprint in comparison with prior art products. Even prior art solutions claiming to be eco-friendly have significant disadvantages, including poor processability of main ingredients leading to high fibre loss during processing, poor surface texture of the tampons and poor absorbency,. In generally, hemp fibres are not traditionally used within absorbent hygiene products such as tampons or sanitary towels, mainly due to the coarseness of the fibres which are not typically consistent or soft enough for these applications. Whilst hemp fibres have, to an extent at least, been considered for sanitary products in prior art products, such solutions have offered relatively low hemp content, and the short fibre lengths utilized carry a significant risk of fibre loss, migration and end penetration through the outer web. Indeed, fibre shedding is an issue even in conventional tampons. Furtheromore, absorbency in prior art solutions including hemp fibres is significantly lower than that required for widespread usage, where a higher absorbency is expected and required to address medium and heavy flows.

[0040] One of the problems associated with (even) conventional tampons is that of visual (external) fibre protrusion and shedding (especially those that use so-called eco fibres), and, often, tactile (external) surface roughness, problems not shared with a tampon 10 according to an exemplary embodiment of the invention, which demonstrates low visual shredding.

[0041] A tampon 10 according to exemplary embodiments of the invention provides protection from leakage, being designed to absorb 6 - 9 g of bodily fluids, and a radial expansion of 45-51%.

[0042] Referring to Figure 2 of the drawings, a first exemplary embodiment of the present invention, hereinafter referred to as the veil tampon, comprises a cylindrical body 12 of length substantially 45mm and diameter substantially 12mm, based on a cylindrical body. In an embodiment, the weight of the tampon may be of substantially 2.1 g. The density of the compressed absorbent material forming the body 12 of the veil tampon may be of the order of 0.39g / cm3. The core composition (which is described in more detail hereinafter) may be 40-55% (by weight) of hemp and 45-60% (by weight) of organic cotton. The body is covered with a ‘veil’ 18 or cover comprising, for example, a cotton spunlace / hydroentangled nonwoven fabric with a basis weight of, for example, 30 g / m2. More generally, the veil 18 is a lightweight fabric with a high degree of porosity which can be woven, knitted or nonwoven, and is readily biodegradable. Purely by way of example, in terms of the weight of the body, the ratio of the veil 18 to the body or ‘core’ might be 40:60.

[0043] Referring to Figure 3 of the drawings, a second exemplary embodiment of the present invention, hereinafter referred to as the non-veil tampon, again comprises a cylindrical body or core 12 formed of a compressed material of density of the order of 0.35 g / cm3. In this case, the weight of the tampon can be slightly less than that of the veil tampon described above, at around 1.9g. In this case, the core composition is in two parts. A first part forms around 25% the overall weight of the core and is formed of alginate and organic cotton in a substantially 1 :1 ratio. The second part forms around 75% of the overall weight of the core, and is formed of hemp and organic cotton in a substantially 3:1 ratio. In some example embodiments, an alginate may be incorporated into the outer layer of the tampon body 12.

[0044] In a first exemplary embodiment of a non veil tampon of the type described above, the total hemp content may be of the order of 53%. In a core of weight around 1 ,8g, the compressed material beneficially comprises around 56% hemp, around 31 % organic cotton, and around 13% alginate. The string (~0.1g) may be formed of 100% organic cotton. The length of the tampon without the string may be around 45mm, increasing to around 200mm including the string. As stated previously, the diameter of the core would be around 12mm if a circular cross-section is assumed.

[0045] In use, radial expansion of an example tampon can be expected if around 45-51 % (e.g. 48%) and the average syngina absorbency may be around 3 + / - 0.2g for the tampon as a whole.

[0046] Referring now to Figures 4 to 6 of the drawings, in a manufacturing process for an exemplary embodiment of the non-veil tampon described above, a tampon ribbon 20 comprising a dual-layered material having a first layer 22 (A in Figure 10) and a second layer 24 (B in Figure 10) is prepared. The first (outer) layer 22 comprises an organic cotton fibre of areal density around 42grm2(or a blend of organic cotton fibre with a small amount (e.g. 2-5% weight) of an alginate) and the second (inner) layer may comprise a blend of organic cotton and hemp fibre, with a ratio of around 25:75 and an areal density of around 124 gm-2. The ratio of the weights of the outer layer 22 and the inner layer 24 may be around 25:75, although all of these values can vary, at least to a certain extent, in other embodiments. In an embodiment, the dual-layered material is formed by a carding process with a 100 % cotton (optionally with a small amount of alginate) outer batt / web and a 75 % hemp 125 % cotton inner batt / web. The resultant material comprises two distinct, but integral, layers of fibres in a frictionally entangled, self-supporting network.

[0047] Thus, the ‘outer’ layer of the dual-layered material referenced above may comprise 100% organic cotton (optionally incorporating a small amount of alginate) processed (i.e. carded) so as to comprise a frictionally entangled, self-supporting fibrous network. The ‘inner’ layer beneficially comprises a mixture of cottonised (optionally bleached) hemp fibres, blended with cotton fibres, which are carded and mechanically bonded to produce a nonwoven with an entangled, frictionally self-supporting fibrous network. Cottonised hemp is a form of hemp fibre that results from a process that reduces the mean fibre diameter and decreases the fibre’s flexural rigidity, producing a softer handle when the fibre is converted into fabric. In one embodiment, the ratio of hemp to cotton in the inner layer may be 3:1 (i.e. -75% hemp:~25% cotton) by weight. Carding is a drylaid nonwoven web forming process whereby staple fibres (typically of 20-60mm length) are mechanically opened, preferentially aligned in the machine direction and formed into a web using rotating rollers covered with wire teeth. In contrast, airlaying involves dispersing short fibres (typically of length <15mm) in an airstream and depositing them randomly onto a moving belt or perforated drum. However, airlaid fibre webs, which consist of much shorter fibres than are used in carding are prone to fibre shedding. In contrast, the frictionally entangled, self-supporting fibrous network of the carded dual-layered material provides good absorbency and expansion, coupled with higher resistance to fibre shedding (than airlaid fibre webs).

[0048] Referring to Figure 10 of the drawings, a scanning electron microscopy (SEM) image of a small portion (cross-section) of the dual-layered material is provided, illustrating the finer fibres a of the outer organic cotton (or cotton / alginate blend) layer A, and the mixture of coarse hemp fibres b1 and finer cotton fibres b2 of the inner cottonised hemp / cotton layer B.

[0049] Referring specifically to Figure 5 of the drawings, a length of string 16 is folded in half and the ends secured together, the overall length of the (folded) string 16 being, perhaps, 200mm. The tampon ribbon 20 is threaded through the opening defined between the two ends of the string 16 and a ribbon roll process (see Figure 5A) is performed first, followed by compression of the tampon ribbon 20 using, for example, a hydraulic press or the like, to create a compressed core12, with the end of the string at which the two ends thereof are joined extending from the “bottom” end of the core 12. The rounded tampon head 14 is formed during the manufacturing process in a conventional manner, as will be known to a person skilled in the art, and will therefore not be described in any further detail herein. Thus, in this exemplary embodiment, the outer layer 22 (A) of the tampon ribbon may be formed of (optionally alginate and) organic cotton, and the inner layer 24 (B) may be formed of hemp and organic cotton, in a ratio of substantially 3:1 , giving a total hemp content of the tampon (including the string, which is formed of organic cotton) of around 53%. The ratio (in terms of thickness) of the outer and inner layers of the tampon ribbon 20 may be substantially 1 :3 and, as stated above, the tampon density might be expected to be approximately 0.35g / cm3.

[0050] The soft alginate fibres selected for the outer layer 22 of the ribbon 20 are designed to minimize rough surface and visual protrusion of the hemp fibres, and the addition of organic cotton to the outer layer 22 of the ribbon 20 provide improved cohesion between outer ribbon fibres and prevent excess shedding.

[0051] The hemp and cotton fibre ratio of 3: 1 in the inner layer 24 of the ribbon 20 is chosen to maximise sustainability credentials whilst maintaining processability of the carded web (used to produce the tampon from the ribbon 20). The fibre composition is selected to maximise hemp content while maintaining good absorbency.

[0052] The tampon density 0.35 g / cm3is relatively low, and is proven to provide better gram for gram tampon absorbency for cotton and hemp tampons. Thus, the lowest required tampon density has been utilized. In the table provided below, some key data is provided in relation to an example veil tampon according to another exemplary embodiment of the invention.

[0053] In an exemplary manufacturing process for a veil tampon of the type described above, the process starts with a ribbon 26 comprising a strip 28 of an organic (e.g. cotton), carded nonwoven, spunlace material. The nonwoven spunlace material consists of frictionally entangled, self-supporting fibrous networks to optimise comfort and reduce the risk of shedding. The weight per unit area of the spunlace material may be of the order of 30g / m2. The strip 28 of spunlace material is overlaid by a smaller strip 30 of a dual-layered material. The dual-layered material comprises two distinct layers, hereinafter referred to as the outer layer and the inner layer respectively. The strip 30 of dual-layered material overlays the strip 28 of spunlace material such that its outer layer is immediately adjacent the strip 28 of spunlace material. Beneficially, the outer layer may comprise 100% organic cotton processed so as to comprise a frictionally entangled, self- supporting fibrous network. For example, the outer layer may be formed of 100% carded nonwoven organic cotton. The inner layer beneficially comprises a mixture of cottonised (optionally bleached) hemp and cotton fibres, carded and nonwoven to provide a frictionally entangled, self-supporting fibrous network. Cottonised hemp is fabric that results from a process aimed at softening hemp fibres to achieve a gentle, cotton-like texture, as will be known to a person skilled in the art. In an embodiment, the ratio of hemp to cotton in the inner layer may be 3:1 (i.e. -75% hemp:~25% cotton). Carding is a drylaid nonwoven process whereby staple fibres (typically of 20-60mm length) are mechanically opened, aligned and formed into a web using rotating rollers with wire teeth. In contrast, airlaying involves dispersing short fibres (typically of length <15mm) in an airstream and depositing them randomly onto a moving belt or perforated drum. However, airlaid fibres, which are thus typically much shorter than drylaid nonwoven fibres, exhibit an absorbency and expansion that is significantly lower than that offered by conventional tampons, and the degree and incidence of shedding is high. In contrast, the frictionally entangled, self-supporting fibrous network of the carded dual-layered material provides a much higher absorbency and expansion, and much lower degree of shedding due to the longer fibres present therein.

[0054] Referring to Figure 10 of the drawings, a scanning electron microscopy (SEM) image of a small portion (cross-section) of the dual-layered material is provided, illustrating the finer fibres a of the outer organic cotton layer A, and the mixture of coarse hemp fibres b1 and finer cotton fibres b2 of the inner cottonised hemp / cotton layer B.

[0055] The strip 30 of dual-layered material is located on the larger spunlace strip 28 laterally centrally but off-centre relative to the longitudinal axis such that there is a greater width of the spunlace strip 28 above the dual-layered strip 30 than below it. The length of the spunlace strip 28 may be around 240mm and its width may be of the order of 115mm, whereas the length of the dual-layered strip 30 may be of the order of 200mm and its width may be of the order of 35mm. The areal density of the dual-layered strip 30 may be around 170gm-2.

[0056] A length of string 16 is folded in half and the ends secured together, the overall length of the (folded) string 16 being, perhaps, 200mm. The tampon ribbon 26 is threaded through the opening defined between the two ends of the string and a ribbon roll process (see Figure 8A) is performed first, followed by compression of the tampon ribbon 26 to create a compressed core 12, with the end of the string at which the two ends thereof are joined extending from the “bottom” end of the core 12. The rounded tampon head is formed during the manufacturing process in a conventional manner, as will be known to a person skilled in the art, and will therefore not be described in any further detail herein.

[0057] It will be appreciated that, thus rolled, there will be a central core formed by multiple layers of the cottonised hemp / cotton layer (see Figure 8A), the hemp fibres thus being layered within the core of the tampon, and not on the exterior thereof. The softer cotton fibres on the outer surface of the tampon provide comfort properties. A small portion (e.g. 2-5% weight) of low surface friction alginate fibres could be included in the outer layer to contribute to the ease of insertion and removal of the tampon, in use.

[0058] In various embodiments of the invention, the overall hemp content may be 40 - 55% by weight. In this specific embodiment, which includes the spunlace veil layer, the overall hemp content may be of the order of 43%. The veil spunlace weight is minimised to the lowest weight available to achieve the highest possible ratio of core to veil material, thereby optimising the absorbency of the product vs its weight. The ratio of veil to core material might, in some embodiments, be 2:3.

[0059] The core density in this exemplary embodiment is still relatively low, and may be of the order of 0.39g / cm3, still sufficiently low to provide improved gram per gram tampon absorbency when compared with the prior art, whilst retaining a sufficient degree of rigidity to ensure ease of insertion. Indeed, a syngina of 3 + / - 0.2g / g is typical. The core density is designed to be much the same as that of a commercially available cotton veil tampon to provide good absorbency without compromising tampon rigidity. The cotton layer of the dual-layered material contributes significantly to the absorbency of the tampon. The length of the hemp fibres in the dual-layered material is greater at 20- 30mm than that of the hemp fibres utilised in known solutions. Thus, there is significantly lower risk of fibre loss, migration and end penetration, all of which issues pose a significant barrier to the provision of a commercially and practically viable tampon utilizing prior art designs. A median fibre diameter of 25pm + / - 3pm is considered to be advantageous for similar reasons. The length of (at least the majority of) the organic cotton fibres utilized in an example embodiment is >26mm. The longer lengths of the fibres enable the carding process to form a fractionally entangled self- supporting network of fibres, and additional bonding agents are not required.

[0060] The presence of the veil in the second exemplary embodiment of the invention acts to reduce fibre shedding from the outer layer of the tampon, whilst the cotton layer of the dual-layered material, together with the lengths and diameters of the hemp fibres created as a result of the carding process, prevent loss, migration and end penetration of the hemp fibres in the core.

[0061] The exemplary embodiments described above illustrate that a high hemp content (over 40%) can be incorporated into a tampon without decreasing syngina absorption performance (in comparison with conventional cotton tampons), whilst meeting safety, utility and comfort requirements.

[0062] Purely by way of example, the hemp fibres used in some exemplary embodiments of the invention may be cottonised hemp (bleached or unbleached), the cotton fibre could be organic virgin cotton, the alginate fibre (if used) could be calcium alginate fibre, the tampon withdrawal cord or string could be organic cotton Ne 10 / 4 thread, white bleached and hydrophobically treated, and the veil could be any cotton spunlace of, say, 30g / m2.

[0063] The use of the dual-layered material utilized in example embodiments of the tampon means that longer and more hemp fibres can be utilized than in prior art solutions, without compromising safety or utility, to provide a tampon that is comparable to and, in some cases better than, a conventional cotton) tampon. The hemp fibres are layered within the core, and not in the exterior layer, and the hidden soft fibre layers provide improved comfort. Longer hemp fibres can be used due to their cottonized nature, and the fact that they are “buried” within the material forming the core, and the total proportion of hemp within the product can thus be optimized. Various characteristics of an example tampon are summarized in the table below.

[0064]

[0065] Referring to Figure 11 of the drawings, there is illustrated a sanitary towel 100 comprising an elongate pad 120 of compressed absorbent material. The pad 120 is generally rectangular in shape, but the ends are rounded. In this exemplary embodiment, the sanitary towel 100 further comprises a pair of tabs or “wings” 140, one adjacent each longitudinal edge of the pad 120. In prior art sanitary towels, the compressed absorbent material is formed of materials such as bleached rayon, cotton and plastics (polythene, polyethylene, polyacrylates, and / lor polypropylene, for example). In addition, antibacterial and fragrance agents may be incorporated. However, these may, at least in some cases, cause skin irritation. Arguably more importantly, some of the materials used are not fully or readily biodegradable, and the carbon footprint of the products is often high due to the manufacturing processes used. Hemp fibres are not traditionally used within absorbent hygiene products, mainly due to the coarseness of the fibre. However, in an exemplary embodiment of the invention, the pad incorporates a core (20 - see Figures 12, 13 and 15, or example) formed of around 50% cottonised (optionally bleached) hemp, which acts to mitigate one or more of the issues referenced above.

[0066] Referring to Figure 12 of the drawings, in a first exemplary embodiment, there is provided a sanitary towel comprising a pad 120 formed of a core 20 enveloped in an organic cotton spunlace wrap 30. The sanitary towel further comprises a top sheet 16 and a bottom sheet 180, with the core 20 sandwiched between the top and bottom sheets which are bonded to the outer surface of the core 20. The core is formed, in this exemplary embodiment, of an absorbent material formed by a carding process using substantially 50% cottonised (optionally bleached) hemp fibres, and around 50% (preferably organic) cotton fibres. In some embodiments, a small amount (e.g. 2-5% wt) of a (gelling) alginate may be added.

[0067] The hemp and cotton fibres are formed into a core material by carding (i.e. a drylaid nonwoven process), wherein staple fibres (typically 20-60mm long) are mechanically opened, aligned and formed into a web using rotating rollers and wire teeth. In contrast to traditional airlaying (which is typically used to form a material of this type), the fibres within the core material are longer, and layered within the core material such that they provide capillary channels which provide effective wicking across the carded layer. This provides increased core utilization compared with airlaid structures, which utilize shorter fibre lengths (typically <15mm) and wherein the fluid tends to remain near the point of ingress (which can result in pooling and a poor wetback response). The carded material used to form the core 20 requires no additional bonding within the web (instead forming a frictionally self-supporting fibrous network as a result of the carding process), and displays an absorbency per core weight and wetback results comparable to conventional sanitary towels and far superior to prior art proposals incorporating hemp fibres. A scanning electron microscopy (SEM) image of a carded cottonised hemp / cotton material suitable for use as the core in an example sanitary towel is shown in Figure 13 of the drawings, wherein the cottonised hemp fibres 1 and the cotton fibres 2 can be seen within the frictionally self-supporting fibrous network formed by the carding process.

[0068] The total weight of an example sanitary towel 100 may be around 5.7g + / - 0.2g, although it will be understood that this is purely by way of example and the invention is in no way intended to be limited in this regard.

[0069] The top sheet may be formed of cotton and / or cotton spunlace and the core wrap 30 is also beneficially formed of organic cotton spunlace. The back sheet 180 may comprise a film formed of a blend of, for example, polybutylene adipate terephthalate (PBAT) and polyactic acid (PLA), but the present invention is not necessarily intended to be limited in this regard.

[0070] A hotmelt adhesive may be utilized to adhere the various layers of the example sanitary towel. Conventionally, a hot melt adhesive is a thermoplastic, polyer-based adhesive.

[0071] However, there have been recent advancements in more sustainable (e.g. biobased and biodegradable) hot melt adhesives, that may be suitable for use in example sanitary towels. S vbustainable hot melt adhesives may include those derived from biobased polyesters (e.g. PLA, PBS, PHA), natural resins (e.g. rosin, waxes), and biodegradable synthetic polymers (e.g. PCL). .

[0072] A sanitary towel is thus provided that provides protection from leakage, and any plastics used (e.g. for the back sheet and hotmelt adhesive) are readily biodegradable, such that the entire sanitary towel is readily and fully biodegradable, as well as being comfortable and hypoallergenic, and provides characteristics at least comparable to those offered by conventional sanitary towels.

[0073] The characteristics of a specific example sanitary towel are summarized in the table below:

[0074]

[0075] In an alternative exemplary embodiment, a hemp spunlace may be utilized for the core wrap 30, which would increase the overall hemp content of the product. However, cotton spunlace is considered to be advantageous because it is softer and offers better overall performance.

[0076] The blend of 50% hemp and 50% cotton utilized in the example embodiment of the invention described above with reference to Figure 12 of the drawings, provides the required wetback results, rate of absorption and LAC per core area. However, it is thought that wetback results could, in some cases, be improved by using gelling alginate fibre that can lock fluid within the pad. In general, an overall hemp content of an example sanitary towel could be 25-40%, without compromising on performance or comfort.

[0077] Referring now to Figures 14 to 16 of the drawings, in an exemplary process for producing a sanitary towel, a layer 30 of organic cotton spunlace material is folded around a core 20 comprising a carded material formed of cottonised (optionally bleached) hemp fibres and organic cotton fibres (and (optionally) a small quantity of alginate), as described above. Atop sheet 160 (optionally including or formed of spunlace material, but could, for example, comprise woven or knitted organic cotton or similar natural, readily biodegradable material) is bonded to the ‘top’ of the spunlace core wrap 30, and a liquid resistant back sheet 180 (e.g. 30gnr2film) is bonded to the ‘bottom’ of the spunlace core wrap 30 by means of, for example, a hot melt adhesive. The weight of the back sheet 180 may, for example, be 10 - 15 gm-2. It can be seen from Figure 16A that the top sheet 160, which may comprise or include a layer of organic spunlace material, is configured to include the “wings” 140 along the longitudinal side edges. The ‘bottom’ surface of each wing 140 may include a layer of adhesive that may be covered by a strip of material (not shown) that can be removed by the user to adhere each wing to the inner surface of the gusset of their undergarment. In an alternative exemplary embodiment, a layer of adhesive may be provided on the outer surface of the back sheet 180, again (optionally) covered with a removable strip of material, to allow the sanitary towel to be adhered to the outer surface of the gusset of a user’s undergarment.

[0078] Thus, exemplary embodiments of the invention may provide a sanitary towel of thickness of 4mm or less (in some embodiments, the thickness may, for example, be 2.4mm + / -0.2mm), a width (including the wings) of 150mm or less and a weight of 6.5g or less (the core weight may, in some examples, be substantially 250gm-2), whilst being fully and readily biodegradable by using an organic cotton spunlace core wrap, and a core including substantially 50% hemp and 50% organic cotton (and (optionally) a small amount of gelling alginate to further improve absorption). In at least some exemplary embodiments, the liquid absorptive capacity of the core may be 35ml (or more) per 130cm2core area. The total hemp content of a sanitary towel according to at least some exemplary embodiments is 28-30%.

[0079] In an exemplary embodiment, the hemp fibre may, beneficially, comprise cottonised hemp (bleached) hemp fibres of length 20-60mm (more preferably with a median fibre length of 20-30mm, and median fibre diameter of 25 + / -3pm). The length of (at least the majority of) organic cotton fibres utilized in an example embodiment is >26mm. The longer lengths of the fibres enable the carding process to form a frictional ly entangled self-supporting network of fibres, and additional bonding agents are not required. The cotton fibre may, beneficially, comprise organic cotton and the alginate (if used) may comprise calcium alginate fibre. The top sheet 160 and core wrap may be formed of cotton spunlace mesh 30 gm-2, and the backsheet film may comprise a PLA + PBAT film of 30 gm-2. PLA (polactic acid) and PBAT (Polybutylene Adipate Terephthalate) are both biodegradable plastics. It is expected that, in at least some exemplary embodiments, that the construction adhesive will be a hot melt adhesive (preferably biobased or biodegradable hot melt adhesives), examples of which are provided above.

[0080] In both the example tampon and sanitary towel described above, (preferably) organic cotton is utilized, together with the hemp fibres, to form the absorbent material. However, it is envisaged that one or more other (preferably sustainable and natural) material fibres could alternatively, or in addition, be used in the carding process. For example, merino wool.

[0081] It will be apparent to person skilled in the art, from the foregoing description, that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS1 . A tampon comprising an elongate, generally cylindrical body of compressed fibrous absorbent material, wherein said absorbent material comprises two integral, but contacting layers, a first of said layers comprising a frictionally self- supporting fibrous network of hemp fibres and fibres of at least one other natural fibrous material, wherein the lengths of at least a majority of said fibres are 20mm or more, and a second of said layers comprising fibres of said other natural fibrous material and no hemp fibres.

2. A tampon according to claim 1 , wherein the length of hemp fibres in said first layer is 20-60mm.

3. A tampon according to claim 1 or claim 2, wherein a median length of hemp fibres in said first layer is 20-30mm.

4. A tampon according to any of claims 1 to 3, wherein a median diameter of hemp fibres in said first layer is 25 + / -3pm.

5. A tampon according to any of the preceding claims wherein said absorbent material comprises a carded nonwoven material comprising said first and second integral layer.

6. A tampon according to any of the preceding claims, wherein said first layer of said absorbent material comprises a frictionally self-supporting fibrous network of cottonised hemp fibres and fibres of said natural fibrous material.

7. A tampon according to claim 6, wherein said first layer of said absorbent material comprises a frictionally self-supporting fibrous network of bleached cottonised hemp fibres and organic cotton fibres.

8. A tampon according to any of the preceding claims, wherein said first layer of said absorbent material comprises hemp and other fibres in a ratio of substantially 3:1.

9. A tampon according to any of the preceding claims, wherein said cylindrical body is a core comprising multiple-layer roll of said absorbent material, configured such that the second layer forms the outer surface of said core.

10. A tampon according to any of the preceding claims, having an outer layer comprising or including alginate.

11. A tampon according to any of the preceding claims, areal density of the compressed absorbent material is 120 - 130 gm’2.

12. A tampon according to any of the preceding claims, having an overall proportion of hemp of 40-55%wt.

13. A tampon according to claim 12, wherein the density of said compressed absorbent material is substantially 0.30 - 0.40 g / cm3.

14. A tampon according to any of the preceding claims comprising an outer layer formed of a mesh.

15. A tampon according to claim 14 , wherein said mesh comprises spunlace material.

16. A tampon according to claim 15, wherein said mesh comprises a cotton spunlace material.

17. A tampon according to any of claims 14 to 16, wherein the weight per unit area of said mesh is 25 - 35 g / m2.

18. A tampon according to claim 16, wherein the weight per unit area of said mesh is substantially 30 g / m2.

19. A sanitary towel comprising a top sheet and a bottom sheet with an absorbent core therebetween, said core comprising a frictionally self-supporting fibrous network of hemp fibres and fibres of at least one natural absorbent material, the length of a majority of said fibres being 20mm or more.

20. A sanitary towel according to claim 19, wherein said core comprises 40-55% hemp fibres.21 .A sanitary towel according to claim 20, wherein said core comprises 50% hemp fibres.

22. A sanitary towel according any of claims 19 to 21 , wherein said hemp fibres are cottonised hemp fibres.

23. A sanitary towel according to 22, wherein said hemp fibres are bleached cottonised hemp fibres.

24. A sanitary towel according to any of claims 19 to 23, wherein said natural absorbent material comprises cotton.

25. A sanitary towel according to claim 24, wherein said natural absorbent material comprises 100% organic cotton.

26. A sanitary towel according to any of claims 19 to 25, wherein the length of hemp fibres in said core is 20-60mm.

27. A sanitary towel according to any of claims 19 to 26, wherein a median length of hemp fibres in said core is 20-30mm.

28. A sanitary towel according to any of claims 19 to 27, wherein a median diameter of hemp fibres in said core is 25 + / -3pm.

29. A sanitary towel according to any of claims 19 to 28, wherein said core comprises a carded nonwoven material comprising said hemp and other natural fibrous material fibres.

30. A sanitary towel according to any of claims 19 to 29, wherein said core comprises 50% organic cotton fibres.31 .A sanitary towel according to any of the preceding claims, wherein said core additionally comprises gelling fibres.

32. A sanitary towel according to claim 31 , wherein said core comprises gelling alginate fibres.

33. A sanitary towel according to any of claims 19 to 32, wherein the core comprises a pad, said pad being wrapped or enveloped in a layer of material.

34. A sanitary towel according to claim 33, wherein said layer of material comprises cotton.

35. A sanitary towel according to claim 33 or claim 34, wherein said layer of material comprises a mesh.

36. A sanitary towel according to claim 35, wherein said layer of material comprises a spunlace nonwoven material.

37. A sanitary towel according to any of claims 19 to 36, wherein said top sheet is bonded to the upper surface of the core, when the sanitary towel is oriented for normal use.

38. A sanitary towel according to claim 37, wherein said top sheet is bonded to the upper surface of the core by means of a hot-melt adhesive.

39. A sanitary towel according to claim 38, wherein said hot-melt adhesive is a biobased or biodegradable hot-melt adhesive.

40. A sanitary towel according to any of the preceding claims, wherein said top sheet comprises or includes cotton.41 .A sanitary towel according to any of the preceding claims, wherein said top layer comprises or includes a mesh.

42. A sanitary towel according to claim 41 , wherein said top layer comprises or includes a spunlace nonwoven material.

43. A sanitary towel according to any of claims 19 to 42, wherein said top sheet and / or said bottom sheet is shaped and configured to include a pair of wings, each wing being located adjacent a respective longitudinal side edge of said core.

44. A sanitary towel according to claim 43, wherein a bottom surface of each wing, when the sanitary towel is oriented for normal use, is provided with a layer of adhesive material.

45. A sanitary towel according to claim 44, including a removable strip of material covering said layer of adhesive material before said sanitary towel is required for use.

46. A sanitary towel according to any of claims 19 to 45, wherein said bottom sheet is bonded to the bottom surface of said core, when the sanitary towel is oriented for normal use.

47. A sanitary towel according to any of claims 19 to 46, wherein said bottom sheet comprises a film of biodegradable plastic.

48. A sanitary towel according to claim 47, wherein said biodegradable plastic comprises polyactic acid (PLA) and / or polybutylene adipate terephthalate (PBAT).

49. A sanitary towel according to any of claims 19 to 48, having an overall hemp content of 25-35%.

50. A sanitary product including an absorbent material comprising a frictionally self- supporting fibrous network of hemp fibres and another natural fibrous material, wherein the length of a majority of said fibres is 20mm or more.51 .A sanitary product according to claim 50, wherein said hemp fibres comprise cottonised hemp fibres.

52. A sanitary product according to claim 50 or claim 51 , wherein said other natural fibrous material comprises cotton.

53. A sanitary product according to any of claims 50 to 52, wherein said absorbent material comprises a carded nonwoven material comprising said hemp fibres and said other natural fibrous material.

54. A sanitary product according to any of claims 50 to 53, wherein the length of hemp fibres in said absorbent material is 20-60mm.

55. A sanitary towel according to any of claims 50 to 54, wherein a median length of hemp fibres in said absorbent material is 20-30mm.

56. A sanitary towel according to any of claims 50 to 55, wherein a median diameter of hemp fibres in said absorbent material is 25 + / -3pm.

57. A sanitary product according to any of claims 50 to 56, having a an overall hemp content of 25-55%.

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