Absorbent insert pad free of plastic

Abstract

An absorbent insert pad comprising no pervasive plastic materials, includes a biodegradable and compostable nonwoven cellulose-based material for the top and bottom sheets and having a high softness and textile comfort for the surface arranged to be in contact with the skin of a user during use of the absorbent pad. The fibres of the nonwoven material comprising natural plant oils or waxes provides hydrophobic properties for safe and stay dry contact with the skin. The hydrophobic property of the nonwoven material provides a cover stock for the absorbent insert pad which allows liquid through to the inner absorbent core and will not wick moisture from its sealed edges to an outer garment, which is a desirable property to help prevent leakage and at the same time the insert pad protects the supporting article from becoming soiled.

Description

[0001] TITLE OF INVENTION

[0002] Absorbent Insert Pad Free of Plastic

[0003] TECHNICAL FIELD

[0004] (001) The present Invention is a disposable absorbent insert pad constructed without pervasive plastic materials and includes; a biodegradable and compostable nonwoven cellulose-based material for the top and bottom sheets and having a high softness and textile comfort for the surface arranged to be in contact with the skin of a user during use of the absorbent insert pad. Importantly, the fibres of the nonwoven material comprise natural plant oils or waxes providing hydrophobic properties for safe and stay dry contact with the skin and with a lower wet back compared to untreated fibres of cellulose based nonwoven materials.

[0005] BACKGROUND OF THE INVENTION

[0006] (002) Users of absorbent hygiene products desire a high degree of comfort and the material in direct contact with the skin should be soft and stay dry in use to provide this comfort. Users are also looking for more sustainable choices for their needs, so it is desirable to provide products which are; soft, comfortable, made with less resources and are derived from sustainable resources which can be recycled after use - for example; through composting, soil burial, long drop toilets, anaerobically digested, or macerating and flushing into sewage systems, rather than disposed of in landfill or incinerated.

[0007] (003) The environmental and health issues around single use products made with plastic components are becoming a major concern for manufacturers, consumers, and authorities. PP, PE, PLA and other bioplastics are all forms of plastic which can degrade into microplastics and become pervasive in the environment. It is desired to make a plastic free product to help avoid micro plastic pollution.

[0008] (004) There is also a growing desire for products to be made from more sustainable materials which are biodegradable and compostable. Synthetic nonwovens traditionally used as top sheets like PP and PE are naturally hydrophobic and soft, however they are not produced from sustainable resources and are not suitable for composting or other forms of recycling as previously described. PLA (polylactic acid) can be used to make a nonwoven with hydrophobic properties and is derived from starch, which is a sustainable resource, however it requires hot commercial composting to fully biodegrade, so limits the options for recycling.

[0009] (005) The development of cellulose based fibres which comprise natural hydrophobic plant oils or waxes provides suitable materials to make nonwovens for use as cover stocks which are both very soft and stay dry next to the skin without the need for additional hydrophobic treatments for example; through binders, resins, coatings or toxic chemicals like PFAS which are not suitable for recycling through composting or any other means.

[0010] (006) The absorbent core of this invention comprises a biodegradable and compostable tissue or plant-based nonwoven wrapped around fluff pulp and Super Absorbing Polymer. Super Absorbing Polymer (SAP), is a polymer and while currently derived from petrochemicals, it is sometimes incorrectly called a plastic. All plastics are polymers, however not all polymers are plastic and SAP is not a plastic polymer. SAP can also have beneficial water storing properties in the recycled products derived from used insert pads. Additionally, SAP has been shown to biodegrade under composting conditions where there is white rot fungi and lignin (woody plant material), both regularly found in open windrow composting. Furthermore, the research shows that SAP does not constitute a recalcitrant man-made polymer as it is susceptible to natural, fungal degradative processes known to occur in the environment. (Stahl, J.D., Cameron, M.D., Haselbach, J. et al. Biodegradation of superabsorbent polymers in soil. Environ. Sci. & Pollut. Res. 7, 83-88 (2000). https: / / doi.org / 10.1065 / esprl99912.014). Wherein, petrochemically derived plastics have none of the beneficial properties of SAP.

[0011] (007) By having the absorbent insert pad separate from the outer supporting article, it allows for the insert pad to be made without plastic materials and fasteners which are difficult, uneconomical, or not possible to ‘recycle’ for example through composting or anaerobic digestion, as the plastic components would contaminate the process.

[0012] (008) Both composting and anaerobic digestion provide economical and hygienic methods for ‘recycling’ the used insert pads. Both methods require the feedstock being processed to be free of plastic contaminants otherwise the end product is significantly devalued or rendered useless and has to be landfilled.

[0013] (009) There are International Standards which prescribe the conditions that must be met for a material to be compostable for example EN13432 which states:

[0014] - 90% of the total mass of the material is converted to CO2 within 180 days.

[0015] - The germination rate and plant biomass in the compost are more than 90% of those in the corresponding blank compost. - The products of the composting process can be used to enrich soil or are not harmful to plant growth in the area.

[0016] - The product s heavy metals do not exceed the strict limits set in the standard.

[0017] And Australian Standard 4736 (industrial composting) or AS5810 (home composting) includes the above in addition it must meet a worm toxicity test.

[0018] (010) Anaerobic digestion provides a method of ‘recycling’ the insert pads of this invention and has great environmental benefits in that it hygienically processes the used pads in a contained vessel, produces valuable energy which is captured in the form of methane and the remaining biosolids provide valuable soil amendments.

[0019] (Oi l) Applicant is unaware of prior art which meets or describes all the desired properties of this invention for example WO2008 / 147264 discloses the use of nonwoven material for use as a body facing sheet in an absorbent article where the soft feeling may be achieved using fibres / filaments such as cotton, viscose, lyocell, having a high softness and textile comfort. However, these fibres / filaments bind liquid resulting in a wet surface next to the skin, which is not desirable.

[0020] (012) Additionally Prior art for example US 11,672,709 B2 discloses the use of a nonwoven material for use as a body facing sheet in an absorbent article where a lubricant for example silicon, is applied to the nonwoven as a coating to aid in providing less friction and therefore increase comfort. Applicant does not use coatings on the nonwoven in this application.

[0021] SUMMARY OF THE INVENTION

[0022] (013) It is desired to provide an absorbent insert pad, free of pervasive plastic, and is constructed with a biodegradable and compostable plant based nonwoven comprising a natural plant based oil or wax for the top and bottom sheets which provide both soft and stay dry properties for the comfort of the user and at the same time as being made with sustainable materials which can be recycled into soil conditioners through for example; composting, macerated and flushed, anaerobically digested, placed in long drop toilets or simply buried where it will naturally biodegrade rather than be disposed of in landfill or incinerated.

[0023] (014) The absorbent insert pad (1) of this application minimises the resources used for each pad through its simple product design which has a top sheet (2) and bottom sheet (3) glued together at ends seams (4) and side seams (5) with optional side leg elastic (6) encompassing the absorbent core containing fluff pulp and superabsorber polymer (7) which is wrapped in a tissue paper or viscose non-woven (8). There are no plastic components such as waterproof film layers, dispersion layers, no fasteners or landing zones, and no waist elastic or stretch side tabs.

[0024] (015) The absorbent insert pad is made using materials which are generally derived from sustainable sources and can be disposed of or ‘recycled’ by alternate methods after use, other than landfill or incineration.

[0025] (016) The absorbent insert pad can be supported inside reusable garments (9) or disposable garments, diapers or pads which provide separate waterproofing and support.

[0026] (017) The absorbent insert pad has no waterproof film layer, allowing liquid to pass into and through it, so the insert pad can be used for example; as a booster pad to increase the absorbency of a supporting reusable or disposable absorbent waterproof article, or provide absorbency in a reusable waterproof garment.

[0027] (018) The absorbent insert pads (1) can be place one on top of another insert pad (1) to increase the capacity of the insert pads in a supporting article.

[0028] (019) The absorbent core of the insert absorbent pad can be made with but not limited to for example biodegradable and compostable tissue or viscose (8) wrapped fluff pulp and super absorbing polymer (7). Super absorbing polymers (sodium polyacrylate) are generally made from non-sustainable petrochemicals, however there are products being developed from sustainable resources which are chemically identical and with the same performance which can be substituted once they become commercially available.

[0029] (020) Production of the nonwoven top and bottom sheets can be through several types of processes but not limited to for example hydroentangling, air laid, wet laid or spunbonded. The desired structure and hydrophobic properties of the nonwoven will allow liquid to quickly pass through into the inner absorbent core while minimizing wet back.

[0030] (021) It was found by combining a mixture of viscose fibres comprising natural plant oils, with untreated viscose fibres, the level of hydrophobicity can be controlled. Lyocell Dry (a form of viscose) developed and made by Lenzing™ using innovative technology leveraging AKD (Alkyl ketene dimer), provides a suitable hydrophobic viscose fibre for making the nonwoven. Mixtures with varying percentage combinations can be used, for example we found 30% Lyocell Dry and 70% Lyocell provided a nonwoven with sufficient technical parameters for the desired strike through (less than 1 second) and wet back liquid (around 4 g) management when measured by the INDA / EDANA standard. Whereas 100% Lyocell Dry prevented liquid to pass through, which is beneficial if for example, a highly hydrophobic bottom sheet is desired while remaining breathable for comfort.

[0031] (022) Other types of soft absorbent cellulose-based fibres for example, processed cotton, can be treated with plant-based oils or waxes to provide similar hydrophobic properties that are desired for the nonwoven material. Alternatively, cotton fibres which are only mechanically processed and not chemically processed, comprise natural waxes which render the cotton fibres to be naturally hydrophobic and therefore also provide a suitable fibre to make the nonwoven cover stocks for this invention.

[0032] (023) In one embodiment, the top and bottom nonwoven sheets have extending seams around all sides of the pad which are glued together to encompass the inner absorbent core. Importantly, the side seam edges have hydrophobic properties resulting from the natural plant oil or wax whereby moisture does not wick into the seam, this helps prevent the seams from failing due to liquid ingress and additionally prevents wicking from the inner absorbent core via the pad edges onto supporting articles or externally from the supporting articles onto outer clothing where the pad edges might extend outside the supporting waterproof articles.

[0033] (024) It is desired that the glues and adhesives used to make the absorbent insert pad (1) are compostable and / or soluble.

[0034] (025) In another embodiment, the top and bottom nonwoven sheets may be made with different levels of hydrophobicity for example the bottom nonwoven sheet may have a higher level of hydrophobicity to restrict liquid passing through the pad.

[0035] (026) In one embodiment, the back sheet of the insert pad has a high level of hydrophobicity so that it can be used in regular underwear (14) without the need for a supporting waterproof garment. A sanitary pad is one example of where this would be beneficial.

[0036] (027) Another beneficial property of the nonwoven comprising natural plant oil or waxes is that it has natural antimicrobial properties.

[0037] (028) In another embodiment, the side seam (5) edges of the insert absorbent pad (1) can include elastic (6) to provide shaping of the pad to the wearers body.

[0038] (029) In another embodiment, leak guards (16) comprising the hydrophobic nonwoven with elastic edges are glued to each side of the top sheet (2) of the insert pad (1) to provide additional shaping and containment.

[0039] (030) The absorbent insert pad has no plastic fasteners. The garments used for supporting the absorbent insert pad need to be close fitting to ensure the absorbent pad is held against the wearers body. The garments may incorporate different methods to aid in supporting and retaining the pad (1) in use for example but not limited to waterproof inner slings (10), pockets, Velcro hook type fasteners (12) which can grip the outer cover stock (3) of the insert pad (1) or snap fasteners which can snap together through the nonwoven ends of the insert pad. In other examples, the insert pads are held in place simply through friction of the outer supporting article holding the pad against the skin of the wearers body or by using adhesive strips (15) to detachably secure the pad (1) to the pant (14).

[0040] (031) In another embodiment, the absorbent insert pad may be used with a belt to hold the pad to the wears body, the belt is preferably reusable and may comprise by way of example but not limited to; Velcro type fasteners, buttons or snap fasteners. An example of a belt is one which encircles the pad and the wearer, and the belt secures to itself, and where Velcro hook type fasteners on the inside of the belt ‘grip’ to the fibre filaments of the back (3) nonwoven cover stock of the pad (1), securing it in place on the wearer.

[0041] (032) The shape of the absorbent insert pad (1) is not limited and may be for example; rectangular, have curved ends, have wings or be hourglass shaped.

[0042] (033) The size of the absorbent insert pad (1) is not limited and may be for example suitable for; sanitary pads, baby diapers, toddlers, children or adult incontinence, pet care or any other application where absorbent insert pads are used.

[0043] BRIEF DESCRIPTION OF THE DRAWINGS

[0044] (034) The invention is explained in more detail as shown in the illustrations. While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.

[0045] Figure 1. Top or bottom view of an absorbent insert pad.

[0046] Figure 2. Top or bottom view of an absorbent insert pad with cut away section.

[0047] Figure 3. Perspective of an absorbent insert pad with side elastic.

[0048] Figure 4. Environmental view of an absorbent insert pad in a reusable waterproof pant with an inner supporting sling.

[0049] Figure 5. Environmental view of an absorbent insert pad in a reusable waterproof pant with retaining inner Velcro hook type sections. Figure 6. A perspective of an absorbent insert sanitary pad including an environmental view of it in use.

[0050] Figure 7. A perspective of an absorbent insert pad with leak guards.

[0051] DETAILED DESCRIPTION OF EMBODIMENTS

[0052] (035) Figure 1. shows one embodiment of an absorbent insert pad (1) with end seam (4) and side seams (5) and top (2) and bottom (3) nonwoven sheets.

[0053] (036) Figure 2. shows one embodiment of an absorbent insert pad (1) with end seam (4) and side seams (5) and top (2) and bottom (3) nonwoven sheets and with a cut away section shown by dashed lines to show the inner wrap material (8) with fluff pulp and SAP absorbent core (7). The end and side seams comprise glued nonwoven material having hydrophobic properties derived from the plant-based fibres comprising natural plant oils or waxes. Beneficially, the side seams do not wick liquid from the inner absorbent core (7) to outer supporting articles.

[0054] (037) Figure 3. shows one perspective of an absorbent insert pad (1) with end (4) and side seams (5) and top (2) and bottom (3) nonwoven sheets and elastic side seams (6). The elastic side seams help fit the pad to the contours of the user and provide additional containment.

[0055] (038) Figure 4. shows one environmental view of an absorbent insert pad (1) being placed in a reusable waterproof pant (9) that has an inner waterproof sling (10) to support the absorbent insert pad (1), and the pant (9) and pad (1) are fitted to the body of a user (11) shown as dashed lines.

[0056] (039) Figure 5. shows one environmental view of an absorbent insert pad (1) in a reusable waterproof pant (9) with inner Velcro hook type sections (12), where the fibre filament surface of the bottom (3) nonwoven sheet of the absorbent insert pad (1) is retained by the hook sections (12) in the pant (9) helping to hold the pad (1) in place when worn by the wearer (11).

[0057] (040) Figure 6. Shows one embodiment of an absorbent insert pad (1) including optional wings (13), a top sheet (2) and a highly hydrophobic bottom sheet (3) supported in regular underwear (14) on wearer (11). In this embodiment, the bottom sheet (3) nonwoven would comprise for example 100% hydrophobic fibres to provide a breathable and liquid resistant layer to prevent leakage onto the supporting underwear. The sanitary pad would be detachably secured to the pant using adhesive strip (15).

[0058] (041) Figure 7. Shows a perspective view of an insert absorbent pad (1) with top sheet (2), bottom sheet (3) and with end seam (4) and side seam (5) including side elastic (6) and including sections of nonwoven with edge elastic glued to the sides of the top sheet to provide leak guards (16).

[0059] (042) Wherever it is used, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of'. A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised" and "comprises" where they appear.

Claims

AMENDED CLAIMS received by the International Bureau on 20 March 2025 (20.03.2025)1. Absorbent insert pad comprising no plastic materials, includes a nonwoven material arranged to be in contact with the skin of a user during use of the absorbent insert pad, wherein the nonwoven material is made using compostable and biodegradable plant based fibres comprising natural plant oils or waxes to provide hydrophobic properties so that the surface has the desired softness and stay dry properties required for the comfort of the wearer, wherein the absorbent insert pad is constructed with a top sheet and a bottom sheet comprising the hydrophobic nonwoven material encasing an inner absorbent core including a compostable tissue or plant-based nonwoven layer wrapped around fluff pulp and super absorbing polymer to form the central absorbent region used for receiving urine and other bodily fluids, wherein the sides and ends of the top and bottom sheets are glued together providing a non-absorbent region outside the central absorbent region.

2. An absorbent insert pad according to claim 1 where the nonwoven material for the top and bottom sheets are made of viscose fibres comprising natural plant oils for example rosin.

3. An absorbent insert pad according to claim 2 where the nonwoven material for the top and bottom sheets is made using a mixture of viscose fibres comprising natural plant oils or waxes and untreated viscose fibres to adjust the hydrophobic level.

4. An absorbent insert pad according to claim 3 where the nonwoven material for the top and bottom sheets are a mixture of 30% hydrophobic viscose fibres and 70% untreated viscose fibres.

5. An absorbent insert pad according to any of the preceding claims where the nonwoven materials for the top and bottom sheets have different hydrophobicity levels.

6. An absorbent insert pad according to any of the preceding claims where the nonwoven material for the bottom sheet is made with 100% hydrophobic fibres to provide a liquid resistant layer.

7. An absorbent insert pad according to any of the preceding claims where the fibres used to make the hydrophobic nonwoven material are processed cotton comprising natural plant oils or waxes.

8. An absorbent insert pad according to any of the preceding claims where the fibres used to make the hydrophobic nonwoven material are mechanically processed cotton retaining its natural waxes.

9. An absorbent insert pad according to any of the preceding claims where the nonwoven material for the top and bottom sheets has a basis in the weight range 10 to 80gsm.

10. An absorbent insert pad according to any of the preceding claims where the nonwoven material for the top and bottom sheets is made by hydroentangling, spun bonded, air laid or wet laid.

11. An absorbent insert pad according to any of the preceding claims where the glues and adhesives used in construction are compostable and biodegradable.

12. An absorbent insert pad according to any of the preceding claims where the sides of the pad include elastic to aid in fitting to the body of the wearer and providing additional containment.

13. An absorbent insert pad according to any of the preceding claims which include sections of hydrophobic compostable nonwoven with elastic edges which are glued to the sides of the top sheet of the insert pad to form leak guards.

14. An absorbent insert pad according to any of the preceding claims where the absorbent pad is used as an insert pad in reusable waterproof pants or regular underwear.

15. An absorbent insert pad according to any of the preceding claims where the absorbent pad is used as an insert pad in disposable waterproof pants or diapers.

16. An absorbent insert pad according to any of the preceding claims where the pad is used with a belt to secure the pad to the wearer.

17. An absorbent insert pad according to any of the preceding claims where two or more absorbent pads are used together to provide increased capacity.

18. An absorbent insert pad according to any of the preceding claims where the pad can be disposed of after use by methods other than landfill or incinerating for example by composting, commercially composting, anaerobically digested, macerated and flushed, placed in long drop toilets or soil burial.

19. Absorbent insert pad comprising no plastic materials, includes a nonwoven material arranged to be in contact with the skin of a user during use of the absorbent insert pad, wherein the nonwoven material is made using compostable and biodegradable viscose fibres comprising a natural plant oil, rosin, to provide hydrophobic properties so that the surface has the desired softness and stay dry properties required for the comfort of the wearer, whereinthe absorbent insert pad is constructed with a top sheet and a bottom sheet comprising the hydrophobic nonwoven material encasing an inner absorbent core including a compostable wrapping layer for example tissue paper or hydrophilic viscose nonwoven wrapped around fluff pulp and super absorbing polymer to form the central absorbent region used for receiving urine and other bodily fluids, wherein the sides and ends of the top and bottom sheets are glued together providing a non-absorbent region outside the central absorbent region.Statement under Article 19(1)Amendments to Claim 1 and Independent Claim 19 where the word ‘pervasive’ has been removed is intended to clarify that the Absorbent Insert Pad of this application is made with no plastic materials, regardless if they are seen as pervasive or not. This helps differentiate this application from other patents for absorbent articles which use plastic materials, including bioplastics in their product.Amendments to all Claims where the word ‘insert’ has been added between the words absorbent and pad, has been done to be consistent with Claim 1 and independent Claim 19 which describe an Absorbent insert pad. All dependent claims are also for Absorbent insert pads. This amendment helps to clarify that this application is for absorbent insert pads and differentiates it from other types of absorbent articles.

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