Hydro-degradable fluid absorbent and method of manufacturing the same

Abstract

The present invention relates to a hydro-degradable fluid absorbent, such as a hydro-degradable fluid absorbent feminine hygiene product. The fluid absorbent comprises a top sheet (110), an absorbent core (120) and a bottom sheet (130). The bottom sheet (130) in particular is composed of a multi-layer composite structure consisting of one or more barrier layer / s and one or more water-soluble layer / s; optionally attached to a reinforcing layer (510) and the bottom sheet comprises a position adhesive to stick to the garment. The present invention also relates to the method of manufacturing the hydro-degradable fluid absorbent and the multi- layer composite structure of the bottom sheet such as hereinbefore described.

Description

HYDRO-DEGRAD ABLE FLUID ABSORBENT AND METHOD OF MANUFACTURING THE SAMEFIELD OF INVENTION

[0001] The present invention relates to an improved hydro-degradable fluid absorbent, particularly, a hydro-degradable fluid absorbent hygiene product for use as panty liners, sanitary napkins, incontinence pads, packaging, wound dressing, diaper and the like. In particular, the present invention relates to hydro -degradable fluid absorbent componentry, construction and a method of manufacturing the same.BACKGROUND OF THE INVENTION

[0002] The subject matter discussed in the background section should not be assumed to be prior art merely because of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may correspond to implementations of the claimed technology.

[0003] Hygienic management of menstruation is critical for the overall wellbeing of women. However, menstruation is still considered as taboo in many societies even in the 21stcentury leading to several challenges in effective waste management and disposal of feminine hygiene products.

[0004] Rural and many urban areas lack routine and effective waste collection mechanisms, and menstrual waste are often discarded in open fields and water bodies (ponds, lakes, rivers, streams), buried, or burned in the open. Most sanitary pad varieties used are made of cellulose, super absorbent polymers (SAP), plastic covering, and adhesives / glue; many of these components do not decompose easily and remain in the environment thereby polluting soil and water sources. Therefore, disposability of such pads remains an issue, since even disposable sanitary pads may take over 500 years to decompose, posing significant environmental challenge. While efforts have been put into finding a solution e.g. burning or incineration of the menstrual wastes, sanitary pads whenburned (in the open, in burning chambers, or low-quality incinerators), release toxic chemicals (dioxins and furans that are known carcinogens) that are harmful and pose potential health hazards.

[0005] An average menstruating woman uses an average of 3-15 sanitary pads in a cycle. Considering that a menstruation cycle may last up to the age of 50 years, an individual ends up using tens of thousands of sanitary pads in their life time. Without proper disposal mechanism in place, tons of pads end up buried in landfills. The generation of such high quantity sanitary pad waste creates stress on the waste management sector, and sanitary waste management with conventional tool and techniques may pose an immense threat to the land, water bodies, and human health.

[0006] Even though several sustainable products have gained significant popularity over the years, for various reasons still conventional sanitary pads are most widely preferred. However, conventional sanitary pads have several disadvantages, such as use of non-biodegradable material which takes hundreds of years to decompose naturally. Further, sorting and segregation of these products in waste management requires manual handling of the used sanitary pads which is not only unhygienic, but also pose social stigma and biohazard problems leaving the sanitary pads being mostly left unsegregated, and not properly disposed.

[0007] Some efforts have been made for flushable sanitary pads, primarily made of water-soluble layers. Although, these water-soluble pads are flushable, these designs are not robust, and thus do not survive use. Factors such as environmental moisture and the moisture from the absorbent core weaken the water-soluble layer, causing inability of the sanitary pads to provide the required durability (8 hours or longer use). Further, the water- soluble layer of bottom sheet fails during peel off and sticks to the garment. Thus, the prior art sanitary pads are not viable to use.

[0008] US20020065363A1 describes flushable and water-responsive polymer blend compositions constructed with combinations of polymers including polylactic acid and polyvinyl alcohol. It uses a blend of polymers in the making fibers and manufacturing water-sensitive film for flushable articles. However, there are several disadvantages in adopting this approach including but not limited to an additional process which is required in making a water-sensitive film, and the blend of polymers containing water-solublepolymer is exposed to the menstrual fluid, resulting in the loss of structural integrity of the film.

[0009] EP2692318B1 describes a flushable and water-soluble absorbent which comprises water disintegrable base material layer and a water-insoluble and biodegradable resin layer on the water disintegrable base material layer. It includes an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet and an absorbent body between the liquid-permeable top sheet and liquid- impermeable back sheet. The water disintegrable base material may be prepared using a disintegrable crepe tissue and polyvinyl alcohol layer bonded via melt extrusion. Alternatively, the water-insoluble and biodegradable resin layer may be prepared by melt extruding disintegrable crepe tissue and polylactic acid. However, this reference has a disadvantage with regard to flushability, i.e., Poly lactic acid (PLA) coated on the tissue layer would not be flushable due to its strong bond between the layers.

[0010] US8329977 describes a film that is biodegradable and water- sensitive (e.g., water-soluble, water-dispersible, etc.) in that it loses its integrity over time in the presence of water. The film contains a biodegradable polyester, starch, water-soluble polymer, and plasticizer. This invention further mentions use of 5 different materials in a multilayer or a single layer as a blend. However, the blend here is not durable and fails to sustain for long hours due to the presence of water-soluble polymer in the film. Therefore, this reference suffers from structural instability of the film upon exposure to menstrual fluid.

[0011] Thus, in view of the disadvantages of the prior art, there is a need to provide an improved, hydro-degradable fluid absorbent, such as a sanitary pad, pantiliners, incontinence pads, etc. having longer durability and capable of overcoming the limitations and disadvantages of the prior art.OBJECTS OF THE INVENTION

[0012] It has surprisingly been found that the durability of a hydro -degradable fluid absorbent can be improved by providing a bottom sheet comprising a multi-layer composite structure of one or more moisture barrier layer / s and / or one or more water- soluble layer / s.

[0013] Additionally, it was also found that a hydro-degradable fluid absorbent can be further improvised by providing a bottom sheet comprising a multi-layer composite structure of one or more moisture barrier layer / s and / or one or more water-soluble layer / s, wherein at least one moisture barrier layer is sandwiched between two or more water- soluble layers; optionally attached to a reinforcing layer. In addition to improved durability the hydro- degradable fluid absorbent of the present invention demonstrates other advantageous properties, such as improved flexibility, moisture resistance, structural integrity, increased tensile strength and improved elongation properties.

[0014] An object of the present invention is to provide an improved hydro -degradable fluid absorbent, particularly, a fluid absorbent hygiene product having longer durability.

[0015] Another object of the present invention is to provide a hydro-degradable fluid absorbent having a top sheet (110), an absorbent core (120) and a bottom sheet (130) comprising a barrier layer.

[0016] Another object of the present invention is to provide a hydro-degradable fluid absorbent having a multilayer composite structure in the bottom sheet (130). Yet another object of the present invention is to provide a hydro-degradable fluid absorbent wherein the multilayer composite structure in the bottom sheet (130) comprises one or more moisture barrier layer / s (420) and / or one or more water-soluble layer / s (610), wherein at least one moisture barrier layer (420) is sandwiched between two or more water-soluble layers (610).

[0017] Yet another object of the present invention is to provide a hydro-degradable fluid absorbent having a structure with low moisture vapour transmission rate (MVTR).

[0018] Yet another object of the present invention is to provide a hydro-degradable fluid absorbent having advantageous properties, such as improved flexibility, moisture resistance, structural integrity, increased tensile strength and improved elongation properties.

[0019] Yet another object of the present invention is to provide a hydro-degradable fluid absorbent having a reinforcing layer (510) in the bottom sheet (130).

[0020] Another object of the present invention is to provide a hydro-degradable fluid absorbent having high wet strength of the bottom sheet (130), thereby improving the durability.

[0021] Yet another object of the present invention is to provide a method of manufacturing the hydro-degradable fluid absorbent.

[0022] Yet another object of the present invention is to provide a method of manufacturing the bottom sheet of the hydro-degradable fluid absorbent.SUMMARY OF THE INVENTION

[0023] The instant disclosure provides an improved hydro-degradable fluid absorbent. This summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0024] Disclosed embodiments provide an environment friendly hydro-degradable fluid absorbent having longer durability wherein the said hydro -degradable fluid absorbent comprises layers that are made of materials, such that minimum efforts are required for its disposal.

[0025] The present invention provides a hydro -degradable fluid absorbent componentry, construction and a method of manufacturing the same.

[0026] According to an embodiment of the present disclosure there is provided a hydro- degradable fluid absorbent comprising: a. a top sheet (110) formed of hydro-degradable layer; b. an absorbent core (120), optionally with super absorbent polymer; c. a bottom sheet (130) comprising single or bilayer or multilayer composite structure comprising one or more barrier layer / s (420) optionally comprising one or more water-soluble layer / s, (610) optionally attached to a reinforcing layer (510).

[0027] In another embodiment of the present invention, the hydro-degradable fluid absorbent comprises a top sheet (110), an absorbent core (120) and a bottom sheet (130)comprising a bilayer composite structure of one moisture-barrier layer (420) and one water-soluble layer (610), optionally attached to a reinforcing layer (510); and the bottom sheet (130) comprises a position adhesive (210) to stick to the garment. In this, the water- soluble layer (610) is towards core and the moisture -barrier layer (420) or the reinforcement layer is towards garment.

[0028] In a preferred another embodiment of the present invention, the hydro- degradable fluid absorbent comprises a top sheet (110) comprising a hydro-degradable layer; an absorbent core (120) optionally comprising super absorbent polymer (SAP), and a bottom sheet (130) comprising a bilayer composite structure of one moisture barrier layer (420) and one water-soluble layer (610), attached to a reinforcing layer (510) preferably using a water-soluble adhesive (410); and the bottom sheet comprises a position adhesive (210) to stick to the garment. The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.

[0029] In another embodiment of the present invention, the hydro-degradable fluid absorbent comprises a top sheet (110), an absorbent core (120) and a bottom sheet (130) comprising a multilayer composite structure of one barrier layer (420) attached to one water-soluble layer (610) and is coated on a reinforcing layer (510), wherein the bottom sheet (130) is attached to the top sheet, preferably using a water-soluble adhesive (410). The barrier layer is towards core and the reinforcing layer (510) is towards the garment.

[0030] In one embodiment of the present invention, the hydro-degradable fluid absorbent comprises a top sheet (110), an absorbent core (120) and a bottom sheet (130) comprising a multilayer composite structure of one or more barrier layer / s (420) sandwiched between two or more water-soluble layers (610), optionally coated on a reinforcing layer (510). The water-soluble layer is towards core and another water-soluble layer (610) or the reinforcing layer (510) is towards garment.

[0031] A preferred embodiment of the present invention hydro-degradable fluid absorbent comprising: a. a top sheet (110) comprising a hydro-degradable layer; b. an absorbent core (120) optionally comprising super absorbent polymer (SAP);c. a bottom sheet (130) comprising a multi-layer composite structure of one or more moisture barrier layer / s (420) and / or one or more water-soluble layer / s (610), wherein at least one moisture barrier layer / s (420) is sandwiched between two or more water-soluble layers (610); optionally attached to a reinforcing layer (510); and the bottom sheet comprises a position adhesive to stick to the garment.

[0032] The top sheet is made up of flushable fibers selected from a group consisting of wood pulp, viscose fibres, other similar fibers with different ratios of the fibres having basis weight in the range of 40-100 gram per square meter (GSM).

[0033] Bio-fibers or biodegradable fibers may be selected from several biological sources derived from sources such as but not limited to, wood pulp, viscose or the like.

[0034] In a preferred embodiment, the top sheet is having basis weight in the range of 40-80 GSM.

[0035] In an embodiment of the present invention, the absorbent core may be optionally made of super absorbent polymer (SAP) which can be made up of either thick core or thin core.

[0036] In a preferred embodiment of the present invention the thick core of the absorbent core may consist of fluff wood pulp and thin core may consist of ultra (or) high density core of compressed wood pulp.

[0037] In a preferred embodiment of the present invention, the wood pulp core may have a basis weight in the range of 100-700 GSM, preferably in the range of 200 to 600 GSM, more preferably in the range of 200 to 400 GSM and ultrahigh density core has a basis weight in the range of 100 to 500, preferably in the range of 100 to 300 GSM, more preferably in the range of 200 to 300 GSM.

[0038] In a preferred embodiment of the present invention, the moisture-barrier layer (420) of the bottom sheet comprises materials selected from a group consisting of Polylactic acid (PLA), Polyhydroxy alkanotes (PHAs) and its derivatives poly (3- hydroxybutyrate) (PHB), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-4- hydroxybutyrate) (PHBH); Polyglycolic acid (PGA),Polypropylene carbonate (PPC), Polycaprolactones (PCL), , and Polybutylene succinate (PBS) or blends thereof has a basis weight in the range of 3 to 60 GSM, preferably 5 to 40 GSM, more preferably 5 to 20 GSM.

[0039] In a preferred embodiment of the present invention the water-soluble layer (610) of the bottom sheet comprises material selected from a group consisting of Partially hydrolyzed polyvinyl alcohol (PVOH), Hydroxypropyl cellulose, Polyethylene oxide (PEG), Polypropylene oxide (PPG), Polyvinylpyrollidone, Polyvinyl pyridine, Acrylic acid copolymers, Gelatinized starch, Interpenetrated networks of starch with ethylene / vinyl alcohol copolymers, Nylon copolymers, Polyethylene glycol (PEG), Polyacrylamides, and Carboxymethyl cellulose or blend thereof having a basis weight in the range of 1 to 60 GSM, preferably 1 to 40 GSM, more preferably 5 to 20 GSM.

[0040] In a preferred embodiment of the present invention the reinforcing layer (510) is selected from spunlace non-woven sheet or paper or bio-based webs made up of wood pulp, other fibers having a basis weight in the range of 10 to 80 GSM, preferably 20 to 60 GSM, more preferably 20 to 40 GSM.

[0041] In a more preferred embodiment of the present invention the moisture-barrier layer (420) of the bottom sheet is composed of Polylactic acid (PLA). In a more preferred embodiment of the present invention the water-soluble layer (610) of the bottom sheet is composed of Partially hydrolyzed polyvinyl alcohol (PVOH).

[0042] In a further preferred embodiment of the present invention the reinforcing layer (510) is spunlace non-woven sheet.

[0043] In a preferred embodiment of the present invention, a hydro-degradable fluid absorbent comprising: a. a top sheet (110) comprising a hydro-degradable layer; b. an absorbent core (120) optionally comprising super absorbent polymer (SAP); c. a bottom sheet (130) comprising a multi-layer composite structure of at least one layer of PLA sandwiched between at least two layers of PVOH; attached to a spunlace non-woven sheet; and the bottom sheet comprises a position adhesive to stick to the garment.

[0044] Primary technique for constructing the multilayer composite structure (bottom sheet) is co-extrusion. Alternate techniques for constructing the multilayer composite structure (bottom sheet) are encompassed within the scope of the invention which may include and are not limited to use of water-soluble adhesives, hot melt adhesives, thermal bonding and ultrasonic welding, etc. When the multilayer composite structure is processed through co-extrusion technique, other techniques are not required to be performed. Additionally, any of the other techniques can be performed as an alternate to co-extrusion.

[0045] In the present invention there is provided a method of manufacturing a hydro- degradable fluid absorbent comprising: assembling a top sheet (110), an absorbent core (120) with or without super absorbent polymer, a bottom sheet (130) wherein the bottom sheet (130) comprises a multilayer composite structure of one or more barrier layer / s (420) optionally attached to one or more water-soluble layer / s (610) or sandwiched between two or more water-soluble layers (610), optionally attached to a reinforcing layer (510). The bonding of the top sheet (110) and the bottom sheet (130) with the absorbent core (120) sandwiched in between is achieved by suitable industrial bonding techniques such as thermal bonding, hot melt adhesives, water-soluble adhesives, ultrasonic bonding, etc, and combination thereof.

[0046] In the present invention there is provided a method of manufacturing the bottom sheet of the hydro-degradable fluid absorbent, wherein the bottom sheet is produced through a coextrusion process, involving the creation of a multilayer composite structure. The pre-processing stage includes drying the polymers, with PLA dried at 45°C for 4 hours or more and PVOH at 100°C for 3 hours or more. Prior to extrusion, purging is conducted for 2 hours or more using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Using A, B, and C extruders, a three-layer film is formed with PLA sandwiched between PVOH layers and coated onto a non-woven sheet. The extrusion process operates within a temperature range of 150°C to 220°C, with nip roll pressures maintained between 3000 N and 4500 N.BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS:

[0047] The above summary, as well as the following detailed description, are further understood when read in conjunction with the appended drawings. For the purpose ofillustrating the invention, there are shown in the drawings exemplary embodiments of the invention, however, the invention is not limited to the specific disclosure of the drawings. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0048] Figure 1 illustrates a perspective view of the layers of hydro -degradable fluid absorbent, in accordance with an embodiment of the present invention.

[0049] Figure 2 illustrates planar view of the layers of hydro-degradable fluid absorbent, in accordance with an embodiment of the present invention.

[0050] Figure 3 illustrates bottom view of the hydro-degradable fluid absorbent with the absorbent core visible from the peel, in accordance with an embodiment of the present invention.

[0051] Figure 4(a) illustrate single layer structure of the bottom sheet, in accordance with a plurality of embodiments of the present invention.

[0052] Figures 5(a)-5(b) illustrate a bilayer composite structure of the bottom sheet, in accordance with a plurality of embodiments of the present invention.

[0053] Figures 6(a)-6(c) illustrate a tri-layer composite structure of the bottom sheet, in accordance with a plurality of embodiments of the present invention.

[0054] Figures 7(a)-7(b) illustrate a four-layer composite structure of the bottom sheet, in accordance with a plurality of embodiments of the present invention.

[0055] Figures 8(a)-8(c) illustrate a five-layer composite structure of the bottom sheet, in accordance with a plurality of embodiments of the present invention.

[0056] Figures 9(a)-9(c) illustrate a six-layer composite structure of the bottom sheet, in accordance with a plurality of embodiments of the present invention.

[0057] Figures 10(a)- 10(b) illustrate a seven-layer composite structure of the bottom sheet, in accordance with a plurality of embodiments of the present invention.

[0058] Figure 11 provides a flowchart illustrating method of manufacturing of the hydro -degradable fluid absorbent.

[0059] Figures 12-24 provides wet tensile strength comparison data at various time intervals between the single, bilayer and multi-layer composite structure construct of the bottom sheet present invention as described in Examples 1-14.

[0060] Figure 25 provides comparative MVTR data between embodiments of the present invention.

[0061] Figure 26 provides graphical representation of wet tensile strength of all the hydro -degradable fluid absorbents of the present invention detailed in Examples 1 - 14.

[0062] Figure 27 provides a pictorial representation of the dimensional stability exhibited by the present invention vis-a-vis the dimensional deformity exhibited by the single layer and bi-layer absorbent materials as described in the comparative examples.REFERENCE NUMERALS

[0063] 110- Top sheet

[0064] 120- Absorbent core

[0065] 130- Bottom sheet

[0066] 140- Release liner

[0067] 210- Position adhesive

[0068] 310- Absorbent core after peel

[0069] 410- Water-soluble adhesive

[0070] 420- Barrier layer,

[0071] 510- Reinforcing layer,

[0072] 610-Water- soluble layer,

[0073] 400-1900 -Different embodiments of the multilayer composite structureDETAILED DESCRIPTION OF THE INVENTION

[0074] The terms and words used in the following description and claims are not limited to the bibliographic meanings, but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose oflimiting the scope of the invention as defined by the appended claims and their equivalents.

[0075] The present invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practised according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in details so that the invention is not unnecessarily obscured.

[0076] The present invention relates to hydro-degradable absorbent product having longer durability ideally suited for sanitary uses, particularly for the absorption of aqueous body fluids. In addition to improved durability the hydro -degradable fluid absorbent of the present invention demonstrates other advantageous properties, such as improved flexibility, moisture resistance, structural integrity, retention of wet tensile strength during use and improved elongation properties.

[0077] In an embodiment of the present invention, there is provided a hydro-degradable fluid absorbent comprising: a. a top sheet (110) formed of hydro-degradable layer; b. an absorbent core (120), optionally with super absorbent polymer; c. a bottom sheet (130) comprising single or bilayer or multilayer composite structure comprising one or more barrier layer / s (420) optionally comprising one or more water-soluble layer / s (610), optionally attached to a reinforcing layer (510).

[0078] Further, each embodiment described in this disclosure is provided merely as an example or illustration of the present invention and should not necessarily be construed as preferred or advantageous over other embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present inventionmay be practiced without these specific details. The embodiments provided herein are for the purpose of filing the present complete specification for which provisional application was filed earlier; however, further embodiments within this disclosure are possible and shall / may be covered in the complete specification.

[0079] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. In addition, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[0080] The terms “or” and “and / or” as used herein are to be interpreted as inclusive or meaning any one or any combination. Therefore, “A, B or C” or “A, B and / or C” mean “any of the following: A; B; C; A and B; A and C; B and C; A, B and C.” An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.

[0081] The term “hydro-degradable” as used herein means that the product undergoes four different mechanisms such as dissolution, delamination, disintegration and degradation when exposed to water environment. The term "dissolve" as used herein means that the product is able to breakdown via hydrolysis and / or aqueous products in concentrations generally harmless to the environment. The term “disintegrate” as used herein means that the product is able to break up into small parts as the result of impact or decay and also to lose strength or cohesion and gradually fail. The term “delamination” as used herein is the process where the layers of the sanitary pad separate when exposed to water and mechanical forces during flushing. This separation of layers, prevents ballooning as seen in conventional absorbent, allowing the pad disintegrate easily, preventing blockages in the sewer system. The term “degradation” as used herein is the process by which a material or substance is broken down into simpler or more basic components; such as water, carbon dioxide and other byproducts. This process ensures that the pad's remnants do not persist in the environment.

[0082] The wood pulp, polyvinyl alcohol and polylactic acid may, dissolve / disintegrate out of the structures of the present invention; biodegrade and / or; chemically degrade via simple environment / compost waste treatment conditions or sewage treatment process.

[0083] The terms “top sheet”, “bottom sheet” and “core” as used herein, have the meaning conventional in the sanitary napkin art. Specifically, the top sheet is the layer adjacent to the human skin; the bottom sheet is the layer remote from the skin; and the core is the batting material sandwiched between top sheet and bottom sheet. The absorbent product may contain one or more layer / s.

[0084] The top sheet used in hygiene product has the below important functions:• Collect the bodily fluids and pass it to the absorbent core which can absorb and hold body fluids,• Have a long lasting, and leak proof functionality; and• Does not compromise on the comfort of the wearer in terms of wettability, durability, bulk, and softness;• Causes negligible noise on wear and movement.

[0085] The present invention as disclosed herein, in addition to achieving improved durability and other advantageous properties, such as improved flexibility, moisture resistance, structural integrity, retention of wet tensile strength during use and improved elongation properties, the hygiene product is also aimed at being a flushable, i.e., the top sheet should not only collect discharge and pass it to absorbent core, and feel comfortable to wearer, but also effectively disintegrate upon disposal in the toilet. The top sheet properties should be such that it survives the use and upon being discarded / flushed, also gets disintegrated or hydro -degraded in the toilet and / or plumbing / sewage system.

[0086] As used herein the term "non-woven" means a layer of material having a structure of individual fibres or threads which are interlaid together, but not in an identifiable manner like a knitted fabric is so constructed. Non-woven materials or layers may be synthesized using several processes such as but not limited to, hydro-entangling processes, wet-laid processes, air laid processes, carded web processes, etc. The basis weight of non-woven material is expressed in ounces of material per square yard (OSY) or grams per square meter (GSM).

[0087] Grams per square meter (GSM) is a metric used to measure the weight per unit area. A higher GSM indicates heavier and usually higher thickness. Different GSM valuesare suitable for various purposes based on the weight and texture. This unit is typically useful in understanding the weight of a fabric in textile industries.

[0088] GSM is calculated by determining the weight of a sample material (in grams) and dividing it by the area of the sample (in square meters). The calculation follows the formula:GSM Weight of sample (grams)Area of sample (square meters)

[0089] To measure GSM, a sample of the material is cut to a specific area, typically 100 square centimetres (0.01 square meters) or 1 square meter, and then weighed. The resulting weight is used to calculate the GSM, which represents the material's mass per unit area. This metric is commonly used to assess the density, thickness, and durability of materials such as textiles, paper, and films.

[0090] For a sanitary pad, the top sheet properties should be such that it survives during the use and when discarded / flushed, disintegrate or break in the toilet and / or plumbing / sewage system.

[0091] The hydro-degradable fluid absorbent of the present invention comprises a) a top sheet (110) formed of hydro-degradable layer; b) an absorbent core (120), optionally with super absorbent polymer; c) a bottom sheet (130) comprising of single or bilayers or multilayers composite structure consisting of one or more barrier layer / s (420) (such as, but not limited to Polylactic acid (PLA), Polyhydroxy alkanotes (PHAs) and its derivatives poly (3 -hydroxybutyrate) (PHB), poly (3 -hydroxybutyrate- co-3- hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-4- hydroxybutyrate) (PHBH); Polyglycolic acid (PGA), Polypropylene carbonate (PPC), Polycaprolactones (PCL), , Polybutylene succinate (PBS), etc), or blend thereof, optionally attached to one or more water-soluble layer / s (610) or sandwiched between two or more water-soluble layers (610) made of materials (such as, but not limited to partially hydrolyzed polyvinyl alcohol, (PVOH) Hydroxypropyl cellulose, polyethylene oxide (PEG), polypropylene oxide (PPG), polyvinylpyrollidone, polyvinyl pyridine, acrylic acid copolymers, gelatinized starch, interpenetrated networks of starch with ethylene / vinyl alcohol copolymers, nylon copolymers, polyethylene glycol (PEG), polyacrylamides, polyacrylic acid copolymer, carboxymethyl cellulose, blend thereof etc., and these multilayerscomposite structure were optionally attached to a reinforcing layer (510) which can be any hydro-degradable material (such as, but not limited to spunlace non-woven sheet or paper or bio-based webs made up of wood pulp, other fibers, etc.

[0092] The hydro -degradable fluid absorbent particularly includes a top sheet (110), an absorbent core (120) and a bottom sheet (130). The bottom sheet is made using a single or bilayer or multilayer composite structure, at least one moisture -barrier layer (420), and optionally attaching to at least one water-soluble layer (610). The bottom sheet is optionally attached to on a reinforcing layer (510) to which a release liner (140) is attached. As shown in Figure 1, the hydro-degradable fluid absorbent (100) comprises of a plurality of layers joined together to form a fluid absorbent. The said plurality of layers incorporates a top sheet (110) which is, preferably made of a hydro-degradable layer, an absorbent core (120), optionally with a super absorbent polymer, and a bottom sheet (130) preferably comprising a plurality of layers attached to the release liner (140).

[0093] Figure 2 describes a planar view (200) of a top sheet (110), absorbent core (120), and a bottom sheet (130) of the hydro-degradable fluid absorbent. The bottom sheet (130) with a multilayer composite structure is attached to the top sheet (110) with the help of a suitable bonding technique. Position adhesive (210) is applied to the garment side of the bottom sheet which is further protected by a release liner (140) as shown in Figure 2.

[0094] Figure 3 illustrates a bottom view (300) of the hydro-degradable fluid absorbent’s absorbent core visible by tearing the bottom sheet open (310), preferably with a super absorbent polymer. The absorbent core (120) may be any one of wood pulp core ranging between 100-700 GSM, preferably in the range of 200 to 600 GSM, more preferably in the range of 200 to 400 GSM and ultrahigh density core has a basis weight in the range of 100 to 500, preferably in the range of 100 to 300 GSM, more preferably in the range of 200 to 300 GSM.

[0095] According to an embodiment illustrated by Figure 4(a), a bottom sheet (130) is a single layer structure (400) consisting of one moisture -barrier layer (420) which is attached to the top sheet preferably by using a water-soluble adhesive (410).

[0096] Figure 5(a) illustrates a preferred embodiment wherein the bottom sheet (130) is a bilayer composite structure (500) consisting of one moisture-barrier layer (420) attached to a reinforcing layer (510) preferably by using a water-soluble adhesive (410).Further, the bottom sheet is attached to the top sheet (110) preferably by using a water- soluble adhesive (410). The moisture-barrier layer (420) is towards core and the reinforcing layer (510) is towards garment.

[0097] Figure 5(b) describes the bilayer composite structure (600) of the hydro- degradable bottom sheet (130) consisting of one moisture moisture-barrier layer (420) and one water-soluble layer (610). The water-soluble layer (610) is towards core and the moisture-barrier layer (420) is towards garment.

[0098] Figure 6(a) describes the multilayer composite structure (700) consisting of one moisture-barrier layer (420) and one water-soluble layer (610) further attached to a reinforcing layer (510) preferably by using a water-soluble adhesive (410). The water- soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.

[0099] Figure 6(b) describes a multilayer composite structure (800) of the bottom sheet consisting of one moisture-barrier layer (420) attached to one water-soluble layer (610). The moisture-barrier layer (420) and the water-soluble layer (610) are further coated on a reinforcing layer (510). The moisture -barrier layer (420) is towards core and the reinforcing layer (510) is towards garment. The bottom sheet (130) is further attached to the top sheet (110) preferably by using a water-soluble adhesive (410).[000100] Figure 6(c) describes a multilayer composite structure (900) of the bottom sheet consisting of one moisture-barrier layer (420) and sandwiched between two water-soluble layers (610). The one water-soluble layer (610) is towards core and another water-soluble layer (610) is towards garment.[000101] Figure 7(a) describes a multilayer composite structure (1000) of the bottom sheet consisting of one moisture-barrier layer (420) sandwiched between two water- soluble layers (610), wherein the said multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000102] Figure 7(b) describes that the multilayer composite structure (1100) of the hydro -degradable bottom sheet consisting of two moisture- barrier layers (420) and two water-soluble layers (610) both attached to each other alternatively in which the water-soluble layer (610) is towards core and the moisture-barrier layer (420) is towards garment.[000103] Figure 8(a) illustrates a multilayer composite structure (1200) of the hydro- degradable bottom sheet consisting of two moisture-barrier layers (420) and two water- soluble layers (610) attached with each other alternatively, wherein the multilayer composite structure is attached to a reinforcing layer (510) preferably using a water- soluble adhesive (410). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000104] Figure 8(b) illustrates a multilayer composite structure (1300) of the hydro- degradable bottom sheet comprises of two moisture-barrier layers (420) and two water- soluble layers (610) attached with each other alternatively in which the multilayer composite structure is coated on a reinforcing layer (510). The moisture-barrier layer (420) is towards core and the reinforcing layer (510) is towards garment. The said bottom sheet is attached to the top sheet (110) preferably by using a water-soluble adhesive (410).[000105] Figure 8(c) illustrates a multilayer composite structure (1400) of the hydro- degradable bottom sheet comprises of two moisture -barrier layers (420) and three water- soluble layers (610), attached with each other alternatively in which one water-soluble layer (610) is towards core and another water-soluble layer (610) is towards garment.[000106] Figure 9(a) illustrates a multilayer composite structure (1500) consisting of two moisture-barrier layers (420), three water-soluble layers (610) attached to each other alternatively; wherein the multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000107] Figure 9(b) illustrates a multilayer composite structure (1600) consisting of three moisture-barrier layers (420), two water-soluble layers (610) attached with each other alternatively; wherein the multilayer composite structure is attached to a reinforcing layer (510) preferably using a water-soluble adhesive (410). The moisture -barrier layer (420) is towards core and the reinforcing layer (510) is towards garment. The said bottom sheet (130) is attached to the top sheet (110) preferably by using a water-soluble adhesive (410).[000108] Figure 9(c) illustrates a multilayer composite structure (1700) of the bottom sheet comprises three moisture-barrier layers (420) and three water-soluble layers (610) attached to each other alternatively. The water-soluble layer (610) is towards the core and the moisture-barrier layer (420) is towards the garment.[000109] Figure 10(a) illustrates a multilayer composite structure (1800) of the bottom sheet comprises three moisture-barrier layers (420) and three water-soluble layers (610) attached to each other alternatively, wherein the multilayer composite structure is attached to a reinforcing layer (510) preferably by using a water-soluble adhesive (410). The water- soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000110] Figure 10(b) illustrates a multilayer composite structure (1900) of the bottom sheet comprises three moisture-barrier layers (420) and three water-soluble layers (610) attached to each other alternatively, wherein the multilayer composite structure is coated on a reinforcing layer (510). The moisture-barrier layer (420) is towards core and the reinforcing layer (510) is towards garment. The said bottom sheet (130) is attached to the top sheet (110) by preferably using a water-soluble adhesive (410).[000111] The bottom sheet includes a multilayer composite structure. This structure is formed by attaching multilayers. The multilayers comprise at least one moisture-barrier layer (420), which may be, for example, PLA. The moisture -barrier layer (420) is attached between two or more water-soluble layers (610), which may include partially hydrolysed PVOH. Pursuant to this, this multilayer composite structure is then coated on a reinforcing layer (510), which may include spunlace non-woven sheet. The moisture-barrier layer (420) optionally sandwiched between the water-soluble layers (610) provides enhanced durability. The multilayer composite structure demonstrates lower moisture vapour transmission rate, better wet strength, better structural integrity compared to other bottom sheets (130) made up of water-soluble layer (610).[000112] The moisture-barrier layer (130) is also capable of a lower moisture vapour transmission rate along with having a consistent wet strength with respect to time, thus restricting the transfer of moisture beyond the barrier layer. This, in turn, provides better barrier and better strength. Adding to this, the reinforcing layer (510) attached to the multilayer composite structure provides extra reinforcement to the bottom sheet (130), enhancing the durability.[000113] Further, the PVOH (Partially hydrolyzed polyvinyl alcohol) in the composite structure of the bottom sheet helps in reducing the basis weight of PLA, such that it disintegrates and degrades at a faster rate. This further helps to reduce brittleness, nonelasticity and noisy characteristics caused by PLA, resulting in better stability and comfort during usage. The non-woven construction also provides better durability during use, by acting as a reinforcing layer (510). The presence of the moisture-barrier layer (PLA) (420), water soluble layer (PVOH) (610) and reinforcing layer (spunlace non-woven sheet) 510) provides the required strength and prevents failure of the pad during peel off. The moisture-barrier layer (420) used in the bottom sheet is made up of PLA which is a biodegradable and environmentally friendly polymer.[000114] Figure 11 illustrates a flow chart of manufacturing of the hydro-degradable fluid absorbent comprises: assembling a top sheet (110), an absorbent core (120) with or without super absorbent polymer, a bottom sheet (130) comprising a multilayer composite structure of one or more moisture-barrier layer / s (420) optionally sandwiched between two or more water-soluble layers (610), optionally attached to a reinforcing layer (510), wherein the water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment side. The bonding of top sheet and bottom sheet with the absorbent core sandwiched in between by suitable industrial bonding techniques such as thermal bonding, hot melt adhesives, water-soluble adhesives, ultrasonic bonding, etc and combination thereof.[000115] The primary technique for constructing the multilayer composite structure (bottom sheet) is co-extrusion. Alternate techniques for constructing the multilayer composite structure (bottom sheet) can include water-soluble adhesives, hot melt adhesives, thermal bonding and ultrasonic welding, etc. If the multilayer composite structure is processed through co-extrusion process, then other techniques are not required to be performed. Additionally, any of the other techniques can be performed as an alternate to co-extrusion.[000116] Co-extrusion coating is a process, in which two or more orifices are arranged in such a manner that two or more materials can be co-extruded through a single die and before getting chilled, the laminar structure is coated on the reinforcing layer. The water- soluble polymer and barrier polymers are fed into different extruders equipped withvarious zone (feed zone, compression zone and metering zone). The different zones have different temperature profile to process the material and then all the materials come to two or more orifices, respectively. The orifices are arranged in such a manner that the conjoint merging and welding of the extrudates takes place and before chilling, a laminar structure form. This laminar structure is coated on the reinforcing layer while it is still in the molten form. The bottom sheet of the present invention is produced through a coextrusion process, involving the creation of a multilayer composite structure. The preprocessing stage includes drying the polymers, with PLA dried at 45°C for 4 hours or more and PVOH at 100°C for 3 hours or more. Prior to extrusion, purging is conducted for 2 hours or more using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Using A, B, and C extruders, a three-layer film is formed with PLA sandwiched between PVOH layers and coated onto a nonwoven sheet. The extrusion process operates within a temperature range of 150°C to 220°C, with nip roll pressures maintained between 3000 N and 4500 N.[000117] Figures 12-24 provides comparative wet tensile strength data at various time intervals between the single layer, bilayer and multi-layer composite structure construct of the bottom sheet of the present invention as described in the Examples 1-14.[000118] Figure 25 provides comparative MVTR (moisture vapour transmission rate) data between embodiments of the present invention.[000119] Figure 26 provides graphical representation of wet tensile strength of all the hydro -degradable fluid absorbents of the present invention detailed in Examples 4 - 11 and Comparative examples 1-3 and 12-14.[000120] Figure 27 provides a pictorial representation of the dimensional stability exhibited by the present invention (Examples 4-11) vis-a-vis the dimensional deformity exhibited by the comparative examples (Examples 1-3 and 12-14).TEST PARAMETERS AND PROCEDURES:[000121] In order to assess the performance of embodiments of present absorbent as disclosed in the forthcoming Examples, the following tests were carried out and the results were recorded:[000122] Moisture Vapor Transmission Rate (MVTR):[000123] The Moisture Vapor Transmission Rate (MVTR) of the bottom sheet was quantified using ASTM E96 standard, which prescribes the methodology for determining the Water Vapor Transmission (WVT) through the bottom sheet under specific temperature and humidity conditions. This evaluation employing the water method hinges on the humidity differential between the test cup and the ambient environment, thereby providing critical insights into the moisture barrier properties of the sheet. Specifically, a lower MVTR value is an indicative of superior performance.[000124] Protocol: a. A test dish, with a surface area of 25 mm2, was filled with distilled water to a level of 3 / 4 ± 1 / 4 inch (19 ± 6 mm) below the specimen. The specimen was then securely affixed to the dish, and the entire assembly was weighed. b. Subsequently, the test assembly was placed in a controlled environment maintained at 32.2 ± 3 °C and 50 ± 2% relative humidity (RH) for a duration of 24 hours. Following this period, the assembly was removed from the controlled environment and allowed to equilibrate to room temperature. The assembly was reweighed, and the weight differential was recorded. The MVTR was computed based on the weight differential using the following formula, which delineates the amount of water vapor that traversed the sheet during the test period:[000125] This method efficaciously measures the sheet's capacity to resist moisture transmission, with lower MVTR values denoting enhanced moisture barrier performance.[000126] Wet tensile strength test:[000127] Wet tensile strength studies are conducted to analyze the tensile strength of bottom sheet under wet condition over a time period of 0 hours to 8 hours. This is performed to determine the dimensional stability of the moisture sensitive bottom sheet when exposed to synthetic blood over the specified time intervals. The bottom sheet is prepared by cutting it into strips with dimensions 25.4 mm in width and 100 mm in length. The synthetic blood (prepared in accordance with ISO 16603) is applied to the center area of each strip, covering a region of 25.4 mm in width by 12.7 mm in height. The strips arecovered under a transparent acrylic tray to prevent evaporation of the synthetic blood. The strips are allowed to remain exposed to the synthetic blood for a period extending up to 8 hours.[000128] Tensile strength is evaluated at specific time intervals: 0 hour, 1 hour, 2 hour, 3 hour, 4 hour, 6 hour, and 8 hour. The tensile strength is evaluated by using a benchtop Universal Testing Machine (UTM) (Lloyd Instruments LS5) while setting the crosshead speed to 300 mm / min and utilizing a load cell with a capacity of 100 N.[000129] Elongation at break:[000130] Elongation at break was assessed for the bottom sheet to facilitate a comparative analysis between the elongation properties of a bilayer composite structure and a multilayer composite structure. The bottom sheet was sectioned into strips with dimensions specified as 25.4 mm in width and 100 mm in length, in accordance with a modified ASTM D882 standard. The evaluation was executed utilizing a benchtop Universal Testing Machine (UTM) (Lloyd Instruments LS5), operating with a crosshead speed of 300 mm / min and equipped with a 100N load cell. The elongation at break was quantified as the percentage increase in length relative to the specimen's original gauge length as the following formula:Increase in qauqe lenqth (mm) . „ „ Elongation at break (%) = - — -y / x 100Original gauge length (mm)[000131] Durability test:[000132] The durability assessment was conducted to ascertain the temporal performance efficacy of the sample, specifically the hydro-degradable fluid absorbent, in meeting its operational criteria. The sample is required to possess sufficient absorbency capacity, while the bottom sheet must exhibit adequate barrier properties and tensile strength to contain the liquid for a designated duration during utilization. The evaluation was performed utilizing synthetic blood, prepared in accordance with ISO 16603 standards, by dispensing it onto the hydro-degradable fluid absorbent material and periodically inspecting the underside for leakage. The total blood volume administered to the sample was 15mL, i.e., 5mL of blood at To to commence the experiment, followed by 5mL of blood every hour for two hours.[000133] Results were recorded on an hourly basis to monitor the condition of the bottom side for any damages or breaches. The experiment was conducted over a 12-hour period or until the time any leaks or structural compromises were observed in the bottom sheet, whichever occurred first.[000134] Flushability:[000135] Toilet bowl (TB) clearance:[000136] The objective of this test is to assess the sample's disposability through a toilet bowl into the drainage or sewer system, in order to ensure that there are no blockages within the toilet plumbing upon disposal. A toilet setup with a 4.5-liter capacity flush tank (a commonly utilized volume) was employed for the experiment. The sample was simulated to mimic typical menstrual use prior to disposal into the toilet bowl. Specifically, 15 mL of synthetic blood was applied to the pad and allowed to sit for 12 hours before disposal.[000137] Initially, it was verified that the flush volume was 4.5 liters (+ / - 0.2 liters). The toilet bowl was then flushed to clear any settled debris. The sample was placed in the bowl, flushed, and observed to determine if the entire sample was cleared from the bowl and water trap pipe, subsequently entering the drain line without causing any surcharges in the bowl. If the sample did not clear the bowl and water trap pipe, and was not visible in the drain line, the flush tank was refilled and the flushing process was repeated. Once the entire sample entered the drain line, the total number of flushes required was recorded.[000138] The pass criteria stipulated that over 95% of the products tested (out of 40 samples) must clear the bowl in no more than two flushes, and that any surcharging of the bowl must remain below the rim in 100% of the tests, as per the Fine to Flush, UK Water Industry Specifications" (WIS 4-02-06).[000139] Drainline (DL) clearance test:[000140] The objective of this test was to ensure that the product can navigate through a household drainage system without issues related to settling or snagging. The household pipeline, known as the foul pipe, is connected to the public sewer line, typically has adiameter of 100 mm, and features a slope of 1:80. The pipeline length from the toilet system to the sewer line is 20 meters.[000141] For the experiment, a toilet setup with a 4.5 -liter capacity flush tank (a commonly utilized volume) was used. The sample was simulated to represent typical product usage before being deposited in the WC bowl. Specifically, 15 mL of synthetic blood was applied to the pad and allowed to sit for 12 hours prior to disposal into the toilet bowl.[000142] Initially, the flush volume was verified to be 4.5 Liters (+ / - 0.2 Liters). The toilet bowl was then flushed to clear any settled debris. The sample was placed in the bowl and flushed. Once the sample entered the drainline, its travel distance along the drainline was monitored. If the sample did not clear the bowl and water trap pipe, the flush tank was refilled and flushing was repeated until the sample entered the drainline. Upon the sample entering the drain, its travel distance along the drainline was measured. The flush tank was refilled, and consecutive flushes were performed until the sample either traversed the 20-meter drainline or remained stationary for three consecutive flushes. If, after five flushes, the sample had not travelled 20 meters from the toilet connection into the drainline, the test was concluded.[000143] The pass criteria specified that, when tested by the aforementioned method, at least 95% of the 40 samples must travel a minimum distance of 20 meters along the drain line within five consecutive flushes and not remain stationary for more than three consecutive flushes. (As per “Fine to Flush, UK Water Industry Specifications" (WIS 4- 02-06)).[000144] Disintegration test:[000145] The disintegration test, as outlined in the "Fine to Flush, UK Water Industry Specifications" (WIS 4-02-06), is designed to evaluate the flushability of non-woven products, ensuring they disintegrate adequately in sewer systems to prevent blockages. The purpose of the test is to simulate the mechanical stresses and flow conditions that the products might encounter once flushed, verifying their suitability for disposal via standard plumbing systems. The procedure involves placing a sample of the product in a baffled conical flask filled with water. This flask is then placed on a rotary shaker and agitated ata speed of 100 rpm for a duration of 3 hours. This agitation mimics the turbulent conditions found in household toilets and sewer systems. After the agitation period, the contents of the flask are poured through a 12.5 mm sieve to determine the extent of disintegration. The test is considered successful if at least 50% of the product's original mass passes through the sieve. This criterion ensures that the product breaks down sufficiently to avoid causing blockages in wastewater systems, thereby making it safe for flushing.Examples:[000146] Example 1 (Comparative):A hydro-degradable fluid absorbent was manufactured comprising a top sheet (110) formed of spunlace non-woven sheet, an absorbent core (120) consisting of wood pulp as a fluff core; a bottom sheet comprising a bilayer composite structure of one moisturebarrier layer (420) and one water-soluble layer (610). The water-soluble layer (610) is towards core and the moisture-barrier layer (420) is towards garment.[000147] The bottom sheet comprises a bilayer composite structure, incorporating one moisture-barrier layer (420); (PLA) and one water-soluble layer (610); (cold-water soluble PVOH), fabricated utilizing a co-extrusion technique. The pre-processing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N. This process facilitates the formation of the bilayer composite structure. The total basis weight of the bottom sheet is approximately 18 GSM, with the individual basis weights of the PLA and PVOH layers being 8 GSM and 10 GSM, respectively. The hydro-degradable fluid absorbent is constructed by bonding the top sheet and bottom sheet, with the absorbent core sandwiched in between, using conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is assessed as described in paragraphs [000122] and the results are presented in Table 1. The wet tensile strength testing of the bottom sheet is performed as detailed inparagraph [000126] and depicted in Figure 12. The durability and flushability of the constructed hydro-degradable fluid absorbent are evaluated as elucidated in paragraphs [000131], and [000134] with the results summarized in Table 1.Table-1Note: The durability testing is stopped at 12 hrs[000148] The bottom sheet, constituted by a bilayer structure incorporating an 8 GSM PLA layer, exhibits a moisture vapor transmission rate (MVTR) of approximately 162 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Post-evaluation, the bottom sheet retains its dimensional stability. The hydro-degradable fluid absorbent, composed of this bottom sheet comprised of bilayer structure, demonstrated a maximal durability of 5 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro- degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the bilayer-structured bottom sheet, the initial measurement recorded was 6.1 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 16.4% was observed. This decrement further extended to 24.6% after an 8-hour exposure period.Example 2 (Comparative):[000149] A hydro-degradable fluid absorbent was manufactured comprising a top sheet (110) formed of spunlace non-woven sheet; an absorbent core (120) consisting of wood pulp as a fluff core, a bottom sheet (130) comprising a bilayer composite structure of one moisture-barrier layer (420) and one water-soluble layer (610). The water-soluble layer (610) is towards core and the moisture -barrier layer (420) is towards garment.[000150] The bottom sheet, comprising a bilayer composite structure with one moisturebarrier layer (420); (PLA) and one water-soluble layer (610); (cold-water soluble PVOH), is fabricated using a co-extrusion technique. The pre-processing stage includes drying the polymers, PLA dried at 45 °C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N, enabling the formation of the bilayer composite structure. The total basis weight of the bottom sheet is approximately 30.5 GSM, with the PLA and PVOH layers contributing 18 GSM and 12.5 GSM, respectively. The hydro- degradable fluid absorbent is constructed by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, employing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as delineated in paragraph [000122] and the results are presented in Table 2. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 13. The durability and flushability of the constructed hydro-degradable fluid absorbent are assessed as described in paragraphs [000131] and [000134], with the findings summarized in Table 2.[000151] Table-2Note: The durability testing is stopped at 12 hrs[000152] The bottom sheet, constituted by a bilayer structure incorporating an 18 GSM PLA layer, exhibits a moisture vapor transmission rate (MVTR) of approximately 158 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Post-evaluation, the bottom sheet retained its dimensional stability (as depicted in Figure 27). The hydro-degradable fluid absorbent, comprising this bottom sheet consisting of a bilayer structure, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro -degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the bilayer- structured bottom sheet, the initial measurement recorded was 16.9 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 0% was observed. This decrement further extended to 18.3% after an 8-hour exposure period.Example 3 (Comparative):[000153] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a bilayer composite structure of one moisture-barrier layer (420) and one water-soluble layer (610). The water- soluble layer (610) is towards core and the moisture -barrier layer (420) is towards garment.[000154] The bottom sheet, comprising a bilayer composite structure with one moisturebarrier layer (420); (PLA) and one water-soluble layer (610); (cold-water soluble PVOH),is fabricated utilizing a co-extrusion technique. The pre-processing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N. This methodology facilitates the formation of the bilayer composite structure. The total basis weight of the bottom sheet is approximately 54 GSM, with the PLA and PVOH layers contributing 24 GSM and 30 GSM, respectively. The hydro-degradable fluid absorbent is constructed by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, employing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as delineated in paragraph [000122] and the results are presented in Table 3. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 14. The durability and flushability of the constructed hydro -degradable fluid absorbent are assessed as described in paragraphs [000131], and [000134] with the findings summarized in Table 3.Table-3Note: The durability testing is stopped at 12 hrs[000155] The bottom sheet, constituted by a bilayer structure incorporating a 24 GSM PLA layer, exhibits a moisture vapor transmission rate (MVTR) of approximately 164 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Post-evaluation, the bottom sheet retained its dimensional stability. The hydro-degradable fluid absorbent, composed of this bottom sheet comprised of bilayer structure, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro -degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the bilayer- structured bottom sheet, the initial measurement recorded was 27.8 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 26.2% was observed. This decrement is persistent and reduced by 3% after an 8-hour exposure period.Example 4 (Inventive):[000156] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a multilayer composite structure consisting of one moisture-barrier layer (420) sandwiched between two water-soluble layers (610), wherein the said multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000157] The bottom sheet, comprising a multilayer composite structure with a moisturebarrier layer (420); (PLA) interposed between two water-soluble layers (610); (cold-water soluble PVOH), is fabricated using a co-extrusion technique. The pre-processing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone,compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N. This process facilitates the formation of the multilayer composite structure, which is subsequently coated onto the reinforcing layer (510) while still in its molten state. The total basis weight of the bottom sheet is approximately 78 GSM, with the reinforcing layer having a basis weight of 50 GSM, and the PLA and PVOH layers contributing 8 GSM and 20 GSM (10 GSM per side), respectively. The hydro -degradable fluid absorbent is constructed by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, utilizing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is assessed as delineated in paragraphs [000122] and the results are presented in Table 4. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 15. The durability and flushability of the constructed hydro -degradable fluid absorbent are evaluated as described in paragraphs [000131], and [000134] with the findings summarized in Table 4.Table-4Note: The durability testing is stopped at 12 hrs[000158] The bottom sheet, constituted by a multilayer composite structure sandwiching an 8 GSM PLA layer between 10 GSM PVOH layer on both side and then extrusion coated on a reinforcing layer (510) (50 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 176 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Post-evaluation, the bottom sheet retained its dimensional stability. The hydro-degradable fluid absorbent, composed of this bottom sheet, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro- degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 18.7 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 0% was observed. This decrement further extended to 20.3% after an 8-hour exposure period.[000159] These findings underscore the superior moisture barrier capabilities, structural integrity under duress, and satisfactory flushability attributes of the hydro -degradable fluid absorbent, rendering it a viable candidate for applications necessitating robust moisture resistance and degradability.Example 5 (Inventive):[000160] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a multilayer composite structure consisting of one moisture-barrier layer (420) sandwiched between two water-soluble layers (610), wherein the said multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000161] The bottom sheet, comprising a multilayer composite structure with one moisture-barrier layer (420); (PLA) interposed between two water-soluble layers (610); (cold-water soluble PVOH), is fabricated utilizing a co-extrusion technique. The preprocessing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) withnip roll pressures maintained between 3000 N and 4500 N. This process enables the formation of the multilayer composite structure, which is subsequently coated onto the reinforcing layer (510) while still in its molten state. The total basis weight of the bottom sheet is approximately 80 GSM, with the reinforcing layer (510) having a basis weight of 50 GSM, and the PLA and PVOH layers contributing 10 GSM and 20 GSM (10 GSM per side), respectively. The hydro-degradable fluid absorbent is fabricated by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, employing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as delineated in paragraph [000122] and the results are presented in Table 5. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 16. The durability and flushability of the constructed hydro -degradable fluid absorbent are assessed as described in paragraphs [000131], and [000134], with the findings summarized in Table 5.Table-5Note: The durability testing is stopped at 12 hrs[000162] The bottom sheet, constituted by a multilayer composite structure sandwiching a 10 GSM PLA layer between 10 GSM PVOH layer on both side and then extrusion coated on a reinforcing layer (510) (50 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 191 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Postevaluation, the bottom sheet retained its dimensional stability. The hydro-degradable fluidabsorbent, composed of this bottom sheet, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro- degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 28.5 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 8.8% was observed. This decrement further extended to 11.2% after an 8 -hour exposure period.[000163] These findings underscore the superior moisture barrier capabilities, structural integrity under duress, and satisfactory flushability attributes of the hydro -degradable fluid absorbent, rendering it a viable candidate for applications necessitating robust moisture resistance and degradability.Example 6 (Inventive):[000164] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a multilayer composite structure consisting of one moisture-barrier layer (420) sandwiched between two water-soluble layers (610), wherein the said multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000165] The bottom sheet, comprising a multilayer composite structure with one moisture-barrier layer (420); (PLA) interposed between two water-soluble layers (610); (cold-water soluble PVOH), is fabricated utilizing a co-extrusion technique. The preprocessing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N. This process facilitates theformation of the multilayer composite structure, which is subsequently coated onto the reinforcing layer (510) while still in its molten state. The total basis weight of the bottom sheet is approximately 82 GSM, with the reinforcing layer (510) having a basis weight of 50 GSM, and the PLA and PVOH layers contributing 12 GSM and 20 GSM (10 GSM per side), respectively. The hydro-degradable fluid absorbent is fabricated by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, utilizing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as delineated in paragraphs [000122] and the results are presented in Table 6. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 17. The durability and flushability of the constructed hydro -degradable fluid absorbent are assessed as described in paragraphs [000131], and [000134] with the findings summarized in Table 6.Table-6Note: The durability testing is stopped at 12 hrs[000166] The bottom sheet, constituted by a multilayer composite structure sandwiching a 12 GSM PLA layer between 10 GSM PVOH layer on both side and then extrusion coated on a reinforcing layer (510) (50 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 169 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Postevaluation, the bottom sheet retained its dimensional stability. The hydro-degradable fluid absorbent, composed of this bottom sheet, demonstrated a maximal durability of 12 hoursdevoid of any leakage or structural compromise. The flushability evaluation of the hydro- degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 33.2 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 16.3% was observed. This decrement further extended to 20.5% after an 8-hour exposure period.[000167] These findings underscore the superior moisture barrier capabilities, structural integrity under duress, and satisfactory flushability attributes of the hydro -degradable fluid absorbent, rendering it a viable candidate for applications necessitating robust moisture resistance and degradability.Example 7 (Inventive):[000168] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a multilayer composite structure consisting of one moisture-barrier layer (420) sandwiched between two water-soluble layers (610), wherein the said multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000169] The bottom sheet, comprising a multilayer composite structure with a moisturebarrier layer (420); (PLA) interposed between two water-soluble layers (610); (cold-water soluble PVOH), is fabricated utilizing a co-extrusion technique. The pre-processing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N. This process facilitates the formation of the multilayer composite structure, which is subsequently coated onto thereinforcing layer (510) while still in its molten state. The total basis weight of the bottom sheet is approximately 84 GSM, with the reinforcing layer (510) having a basis weight of 50 GSM, and the PLA and PVOH layers contributing 14 GSM and 20 GSM (10 GSM per side), respectively. The hydro-degradable fluid absorbent is fabricated by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, utilizing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as delineated in paragraph [000122] and the results are presented in Table 7. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 18. The durability and flushability of the constructed hydro -degradable fluid absorbent are assessed as described in paragraphs [000131], and [000134] with the findings summarized in Table 7.Table-7Note: The durability testing is stopped at 12 hrs[000170] The bottom sheet, constituted by a multilayer composite structure sandwiching a 14 GSM PLA layer between 10 GSM PVOH layer on both side and then extrusion coated on a reinforcing layer (510) (50 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 191 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Postevaluation, the bottom sheet retained its dimensional stability. The hydro-degradable fluid absorbent, composed of this bottom sheet, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro-degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 37.8 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 0.5% was observed. This decrement further extended to 15.6% after an 8 -hour exposure period.[000171] These findings underscore the superior moisture barrier capabilities, structural integrity under duress, and satisfactory flushability attributes of the hydro -degradable fluid absorbent, rendering it a viable candidate for applications necessitating robust moisture resistance and degradability.Example 8 (Inventive):[000172] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a multilayer composite structure consisting of one moisture-barrier layer (420) sandwiched between two water-soluble layers (610), wherein the said multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000173] The bottom sheet comprises a multilayer composite structure, featuring a moisture-barrier layer (420); (PLA) sandwiched between two water-soluble layers (610); (cold-water soluble PVOH), fabricated via a co-extrusion technique. The pre-processing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N, facilitating the formation of the multilayer composite structure, which is subsequently coated onto the reinforcing layer (510) while still in its molten state. The total basis weight of the bottom sheet isapproximately 93 GSM, with the reinforcing layer (510) having a basis weight of 50 GSM, and the PLA and PVOH layers contributing 18 GSM and 25 GSM (12.5 GSM per side), respectively. The hydro-degradable fluid absorbent is fabricated by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, employing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as delineated in paragraphs [000122] and the results are presented in Table 8. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 19. The durability and flushability of the constructed hydro -degradable fluid absorbent are assessed as described in paragraphs [000131], and [000134] with the findings summarized in Table 8.Table-8Note: The durability testing is stopped at 12 hrs[000174] The bottom sheet, constituted by a multilayer composite structure sandwiching an 18 GSM PLA layer between 12.5 GSM PVOH layer on both side and then extrusion coated on a reinforcing layer (510) (50 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 145 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Postevaluation, the bottom sheet retained its dimensional stability. The hydro-degradable fluid absorbent, composed of this bottom sheet, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro- degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainlineclearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 37.6 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 2.4% was observed. This decrement further extended to 14.1% after an 8 -hour exposure period.[000175] These findings underscore the superior moisture barrier capabilities, structural integrity under duress, and satisfactory flushability attributes of the hydro -degradable fluid absorbent, rendering it a viable candidate for applications necessitating robust moisture resistance and degradability.Example 9 (Inventive):[000176] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a multilayer composite structure consisting of one moisture-barrier layer (420) sandwiched between two water-soluble layers (610), wherein the said multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000177] The bottom sheet, comprising a multilayer composite structure, features a moisture-barrier layer (420); (PLA) interposed between two water-soluble layers (610); (cold-water soluble PVOH), fabricated utilizing a co-extrusion technique. The preprocessing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N. This methodology facilitates the formation of the multilayer composite structure, which is subsequently coated onto the reinforcing layer (510) while in its molten state. The total basis weight of the bottom sheet is approximately 95 GSM, with the reinforcing layer possessing a basis weight of50 GSM, and the PLA and PVOH layers contributing 20 GSM and 25 GSM (12.5 GSM per side), respectively. The hydro -degradable fluid absorbent is fabricated by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, utilizing conventionally known techniques such as thermal bonding and, hot melt adhesives. . The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as delineated in paragraphs [000122] and the results are presented in Table 9. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 20. The durability and flushability of the constructed hydro -degradable fluid absorbent are assessed as described in paragraphs [000131], and [000134], with the findings summarized in Table 9.Table-9Note: The durability testing is stopped at 12 hrs[000178] The bottom sheet, constituted by a multilayer composite structure sandwiching a 20 GSM PLA layer between 12.5 GSM PVOH layer on both side and then extrusion coated on a reinforcing layer (510) (50 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 154 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Postevaluation, the bottom sheet retained its dimensional stability. The hydro-degradable fluid absorbent, composed of this bottom sheet, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro- degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerningthe wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 35.1 N / mm. Following 1 hour of exposure to synthetic blood, a reduction in tensile strength by 0% was observed. Further, this decrement is lowered by 8.5% by an 8 -hours of exposure period.[000179] These findings underscore the superior moisture barrier capabilities, structural integrity under duress, and satisfactory flushability attributes of the hydro -degradable fluid absorbent, rendering it a viable candidate for applications necessitating robust moisture resistance and degradability.Example 10 (Inventive):[000180] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a multilayer composite structure consisting of one moisture-barrier layer (420) and sandwiched between two water- soluble layers (610). The one water-soluble layer (610) is towards core and another water-soluble layer (610) is towards garment.[000181] The bottom sheet is engineered as a multilayer composite structure, comprising a moisture-barrier layer (420); (PLA) interposed between two water-soluble layers (610); (cold-water soluble PVOH), fabricated via a co-extrusion technique. The pre-processing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N. This methodology facilitates the formation of the multilayer composite structure. The overall basis weight of the bottom sheet is approximately 84 GSM, with the PLA and PVOH layers contributing 24 GSM and 60 GSM (30 GSM per side), respectively. The hydro-degradable fluid absorbent is fabricated by bonding the top sheet and bottom sheet, with the absorbent core sandwiched between them, employing using conventionally known techniques such as thermal bonding and hot melt adhesives. . The moisture vapor transmission rate (MVTR)of the bottom sheet is evaluated as delineated in paragraphs [000122] and the results are presented in Table 10. The wet tensile strength testing of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 21. The durability and flushability of the constructed hydro-degradable fluid absorbent are assessed as described in paragraphs [000131], and [000134], with the findings summarized in Table 10.Table-10Note: The durability testing is stopped at 12 hrs[000182] The bottom sheet, constituted by a multilayer composite structure sandwiching a 24 GSM PLA layer between 30 GSM PVOH layer on both sides, exhibits a moisture vapor transmission rate (MVTR) of approximately 157 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Post-evaluation, the bottom sheet retained its dimensional stability. The hydro- degradable fluid absorbent, composed of this bottom sheet, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro-degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 27.5 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 22.5% was observed. There is no further drop in the tensile strength with a longer exposure time (8 hours).[000183] These findings underscore the superior moisture barrier capabilities, structural integrity under duress, and satisfactory flushability attributes of the hydro -degradable fluid absorbent, rendering it a viable candidate for applications necessitating robust moisture resistance and degradability.Example 11 (Inventive):[000184] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a multilayer composite structure consisting of one moisture-barrier layer (420) sandwiched between two water-soluble layers (610), wherein the said multilayer composite structure is coated on a reinforcing layer (510). The water-soluble layer (610) is towards core and the reinforcing layer (510) is towards garment.[000185] The bottom sheet comprises a multilayer composite structure, incorporating a moisture-barrier layer (420); (PLA) interposed between two water-soluble layers (610); (cold-water soluble PVOH), fabricated through a co-extrusion technique. The preprocessing stage includes drying the polymers, PLA dried at 45°C for 4 hours and PVOH at 100°C for 3 hours. Prior to extrusion, purging is conducted for 2 hours using various grades of polypropylene with melt flow rates (MFR) ranging from 2 to 20, while adjusting the temperature to ensure thorough cleaning. Then, the PVOH and PLA materials are processed through discrete extruders, each outfitted with designated zones (feed zone, compression zone, and metering zone) and precise temperature profiles (150-220°C) with nip roll pressures maintained between 3000 N and 4500 N. This method facilitates the formation of the multilayer composite structure, which is subsequently applied to the reinforcing layer (510) while in its molten state. The total basis weight of the bottom sheet is approximately 154 GSM, with the reinforcing layer (510) possessing a basis weight of 70 GSM, and the PLA and PVOH layers contributing 24 GSM and 60 GSM (30 GSM per side), respectively. The hydro-degradable fluid absorbent is fabricated by bonding the top sheet and bottom sheet, with the absorbent core interposed between them, using conventionally known techniques such as thermal bonding and hot melt adhesives. . The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as delineated in paragraphs [000122] and the results are presented in Table 11. The wet tensile strengthtesting of the bottom sheet is conducted as detailed in paragraph [000126] and illustrated in Figure 22. The durability and flushability of the constructed hydro -degradable fluid absorbent are assessed as described in paragraphs [000131], and [000134] with the findings summarized in Table 11.Table-11Note: The durability testing is stopped at 12 hrs[000186] The bottom sheet, constituted by a multilayer composite structure sandwiching a 24 GSM PLA layer between 30 GSM PVOH layer on both side and then extrusion coated on a reinforcing layer (510) (70 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 146 g / m2 / 24h, signifying a substantial resistance to moisture vapor permeation and thus, providing exceptional moisture barrier properties. Postevaluation, the bottom sheet retained its dimensional stability. The hydro-degradable fluid absorbent, composed of this bottom sheet, demonstrated a maximal durability of 12 hours devoid of any leakage or structural compromise. The flushability evaluation of the hydro- degradable fluid absorbent encompassed criteria such as toilet bowl clearance, drainline clearance, and disintegration. The absorbent conformed successfully to all established benchmarks as delineated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 52.7 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 9.9% was observed. This decrement further extended to 16.7% after an 8 -hour exposure period.[000187] These findings underscore the superior moisture barrier capabilities, structural integrity under duress, and satisfactory flushability attributes of the hydro -degradable fluid absorbent, rendering it a viable candidate for applications necessitating robust moisture resistance and degradability.Example 12 (Comparative):[000188] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a cold-water soluble PVOH layer, processed either by cast film or blown film extrusion line. The basis weight of the bottom sheet is approximately 35 GSM.[000189] The hydro-degradable fluid absorbent is assembled through the bonding of a top sheet (110) and a bottom sheet (130), with an absorbent core intercalated between them, employing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) for the bottom sheet is evaluated as specified in paragraphs [000142] and the results are documented in Table 12. The assessment of the durability and flushability of the assembled hydro-degradable fluid absorbent is conducted in accordance with the procedures described in paragraphs [000131], and [000134], with the findings presented in Table 12.Table-12Note: The durability testing is stopped at 12 hrs[000190] The bottom sheet, constituted by a cold-water soluble polyvinyl alcohol (PVOH) layer (35 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 889 g / m2 / 24h, indicative of minimal resistance to moisture vapor permeation and thereby providing suboptimal moisture barrier properties. Subsequent to the evaluation, the bottom sheet manifested a loss of dimensional stability, culminating in the wrinkling of the film. The hydro-degradable fluid absorbent, fabricated from this bottom sheet, demonstrated immediate failure upon exposure, evidenced by leakage and structural deformation. The flushability assessment of the hydro -degradable fluid absorbent encompassed parameters including toilet bowl clearance, drainline clearance, and disintegration. The absorbent successfully adhered to all predefined criteria as elucidated in paragraphs [000135], [000139] and [000144]. Regarding the wet tensile strength of the cold-water soluble PVOH bottom sheet, the material failed instantaneously upon exposure to synthetic blood, precluding the execution of the tensile strength assessment.[000191] These observations elucidate the inadequacies of the cold-water soluble PVOH layer in maintaining structural integrity and moisture barrier efficacy, thereby limiting its applicability in scenarios demanding robust moisture resistance and mechanical durability.Example 13 (Comparative):[000192] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet (130) comprising a hot- water soluble PVOH layer, processed by using cast film extrusion line. The basis weight of the bottom sheet is approximately 50 GSM.[000193] The hydro-degradable fluid absorbent is fabricated by affixing a top sheet (110) and a bottom sheet (130), with an absorbent core interposed between them, utilizing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is assessed as detailed in paragraphs [000122] and the results are summarized in Table 13. The evaluation of the wet tensile strength of the bottom sheet is performed as described in paragraph [000126]and depicted in Figure 23. The assessment of the durability and flushability of the assembled hydro-degradable fluid absorbent is conducted in accordance with the methodologies outlined in paragraphs [000131], and [000134] with the results presented in Table 13.Table-13Note: The durability testing is stopped at 12 hrs[000194] The bottom sheet, constituted by a hot- water soluble polyvinyl alcohol (PVOH) layer (50 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 1220 g / m2 / 24h, indicative of minimal resistance to moisture vapor permeation and thereby providing suboptimal moisture barrier properties. The hydro-degradable fluid absorbent, composed of this bottom sheet, demonstrated a durability of 3 hours devoid of any leakage or structural compromise. The flushability assessment of the hydro-degradable fluid absorbent encompassed parameters including toilet bowl clearance, drainline clearance, and disintegration. The absorbent successfully adhered to all predefined criteria as elucidated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 39 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 61% was observed. After the exposure to blood, the bottom sheet manifested a loss of dimensional stability, culminating in the wrinkling of the film.[000195] These observations elucidate the inadequacies of the hot-water soluble PVOH layer in maintaining structural integrity and moisture barrier efficacy, thereby limiting itsapplicability in scenarios demanding robust moisture resistance and mechanical durability.Example 14 (Comparative):[000196] A hydro-degradable fluid absorbent was manufactured comprising: a) a top sheet (110) formed of spunlace non-woven sheet, b) an absorbent core (120) consists of wood pulp as a fluff core, c) a bottom sheet comprising a hot- water soluble PVOH layer, attached to a reinforcing layer (510). The total basis weight of the bottom sheet is approximately 150 GSM. The reinforcing layer (510) has a basis weight of 50 GSM, while the basis weights of hot-water PVOH layer is 100.[000197] The hydro-degradable fluid absorbent is engineered through the adhesion of a top sheet (110) and a bottom sheet (130), with an absorbent core (120) intercalated between them, employing conventionally known techniques such as thermal bonding and hot melt adhesives. The moisture vapor transmission rate (MVTR) of the bottom sheet is evaluated as detailed in paragraphs [000122] and the findings are delineated in Table 14. The wet tensile strength of the bottom sheet is assessed according to the procedure outlined in paragraph [000126] and illustrated in Figure 24. The durability and flushability characteristics of the hydro -degradable fluid absorbent are examined as described in paragraphs [000131], and [000134], with the results summarized in Table 14.Table-14Note: The durability testing is stopped at 12 hrs[000198] The bottom sheet, constituted by a hot- water soluble polyvinyl alcohol (PVOH) layer (100 GSM) coated on a reinforcing layer (510) (50 GSM), exhibits a moisture vapor transmission rate (MVTR) of approximately 1641 g / m2 / 24h, indicative of minimal resistance to moisture vapor permeation and thereby providing suboptimal moisture barrier properties. The hydro-degradable fluid absorbent, composed of this bottom sheet, demonstrated a durability of 3 hours devoid of any leakage or structural compromise. The flushability assessment of the hydro-degradable fluid absorbent encompassed parameters including toilet bowl clearance, drainline clearance, and disintegration. The absorbent successfully adhered to all predefined criteria as elucidated in paragraphs [000135], [000139] and [000144]. Concerning the wet tensile strength of the multilayer composite structured bottom sheet, the initial measurement recorded was 61.9 N / mm. Following an hour of exposure to synthetic blood, a reduction in tensile strength by 53.9% was observed. After the exposure to blood, the bottom sheet manifested a loss of dimensional stability (as depicted in Figure 27), culminating in the wrinkling of the bottom sheet.[000199] These observations elucidate the inadequacies of the hot-water soluble PVOH layer coated on a reinforcing layer (510) in maintaining structural integrity and moisture barrier efficacy, thereby limiting its applicability in scenarios demanding robust moisture resistance and mechanical durability.Comparison of all examples:Moisture vapor transmission rate (MVTR):[000200] Moisture vapor transmission rate (MVTR) of the bottom sheet of hydro-degradable fluid absorbent (Examples 1 to 14 (Inventive Examples and Comparative Examples) is compared in Table 15.Table-15[000201] The moisture vapor transmission rate (MVTR) data is a critical parameter influencing the integrity of moisture- sensitive films. The data reveals that the MVTR of the multilayer composite structure coated on a reinforcing layer (510) is within the range of 150-200 g / m2 / 24h. Conversely, the MVTR values for Cold-water soluble PVOH (CW- PVOH), Hot-water soluble PVOH (HW-PVOH), and HW-PVOH with a reinforcing layer (510) is in the range of 900-1700 g / m2 / 24h. Elevated MVTR values correlate with poor moisture barrier efficacy, permitting moisture permeation through the layer, which compromises the layer's strength and may lead to leakage or rupture. This inferior barrier performance is observed, despite the layers being non-porous. Furthermore, PVOH-based moisture-barrier layers (420) demonstrate a structural deformation upon exposure to moisture.[000202] It can be deduced that the multilayer composite structure incorporating a PLA based moisture-barrier layer (420) demonstrates a moisture barrier efficacy exceeding that of a PVOH based moisture-barrier layer (420) by 300-700% (as depicted in Figure 25). The PLA-integrated multilayer configuration affords this significantly superior moisture barrier characteristics, at half basis weight (78 GSM for Example 4 compared to 150 GSM for Example 14). Further, considering PLA and PVOH based barrier layers alone (without reinforcing layer), the PLA barrier layer delivers this performance at l / 12thof basis weight (28 GSM for Example 4) compared with PVOH based barrier layer (100 GSM for Example 14).Wet tensile strength study:[000203] The wet tensile strength of all the hydro-degradable fluid absorbent (from Examples 1 to 14) is compared and depicted in Figure 26.[000204] In Examples 13 and 14 (Comparative), wherein a HW-PVOH moisture-barrier layer (420) was utilized, a marked reduction in strength was observed (61% and 53%) after just one hour of exposure to synthetic blood, with a progressive deterioration in strength correlating with increased exposure duration. This deterioration, accompanied by structural deformation of the layer, is attributed to the intrinsic hydrophilic properties of PVOH. Conversely, in Examples 4 through 11, which employed a multilayer composite structure incorporating a PLA moisture-barrier layer (420), the samples exhibited structural stability. This enhanced performance is attributable to the PLA moisture-barrier layer’s (420) efficacy in obstructing moisture penetration to the underlying PVOH layer, thereby preserving the PVOH's strength. The combination of the strength of PLA moisture-barrier layer (420), PVOH water-soluble layer and the reinforcing layer (510) contributes to minimal reduction in overall tensile strength. Examples 1 through 3, utilizing a bilayer structure with a PLA moisture-barrier layer (420), also demonstrated structural stability; however, the strength values are lower compared to their multilayer counterparts. This reduced strength is due to the presence of only one PVOH layer, and once it dissolved, demonstrates the PLA layer to exhibit the complete load bearing.[000205] The bottom sheets comprising of PVOH based moisture-barrier layer (420) (with or without a reinforcing layer) revealed a drop in the tensile strength in range of 50-65% after just 1 hour of exposure to synthetic blood. On the contrary, the bottom sheets comprising of multilayer composite structure demonstrate a decrease in the tensile strength in the range of 0-10% in most of the examples and in some cases 0-26% due to the variability in the specimens. The basis weight of PVOH based bottom sheet is 2 to 3 times higher than PLA based multilayer structure, yet the % drop in tensile strength is 3 to 6 times higher for PVOH based bottom sheet.[000206] It can be concluded that the bottom sheets comprising of multilayer composite structures (Example 4 to Example 11) exhibit superior performance relative to the bottom sheets comprising of only PVOH-based moisture-barrier layer (420) (Examples 12 to 14; Comparative) and the bottom sheets comprising of bilayer structure (PLA moisturebarrier layer (420) (Example- 1 to Example-3). Also, the bottom sheets comprising of bilayer structure possess excellent load bearing as compared to the bottom sheets comprising of only PVOH-based moisture-barrier layer (420). The principal advantage of the multilayer composite is its ability to maintain structural integrity and overall layer strength by protecting at least one PVOH layer from moisture. Furthermore, the improved elongation properties of the multilayer structure render it highly suitable for practical applications where flexibility, durability and moisture resistance are important.Elongation at break:[000207] Elongation at break of the hydro -degradable fluid absorbent comprising of bilayer structured bottom sheet and multi-layer composite structured bottom sheet is compared in Table 16.Table-16When comparing Example 1 with Example 4, Example 2 with Example 8 and Example 3 with Example 11, the difference between the tensile strength and elongation at break of the bottom sheet comprising of bilayer structure and the bottom sheet comprising of multilayer composite structure are prominent. The increment in tensile strength and elongation at break for Example 4 is 207% and 158% as compared with Example 1, respectively. Similarly, Example 8 is showing 122% and 214% increase in tensile strength and elongation at break as compared with Example 2, respectively. In addition, the tensile strength and elongation at break for Example- 11 is 90% and 270% higher than the values of Example3, respectively. Multilayer composite structure possesses increase in elongation at break mitigates the inherent brittleness and noise characteristics of PLA, while introducing elasticity that enhances stability and comfort during use and also after the removal from the garment.Durability:

[0001] The durability of all the hydro-degradable fluid absorbent (from Examples 1 to 14) is compared in Table 17.Table-17

[0002] Example 12, comprising a CW-PVOH moisture-barrier layer (420), exhibited immediate failure upon exposure to synthetic blood. In contrast, Examples 13 and 14, which incorporated an HW-PVOH moisture-barrier layer (420), demonstrated that the hydro -degradable fluid adsorbent achieved a durability of 3 hours. This degradation in both instances is ascribed to the inherent hydrophilic nature of PVOH. Example 1, featuring a bilayer structure as the bottom sheet, exhibited a durability of 5 hours. The durability is attributed to the performance of the PLA moisture -barrier layer (420), but as the PVOH layer dissolved upon exposure to synthetic blood, the dissolution of the PVOH layer leads to a decrease in the strength and elongation of the moisture-barrier layer (420). Even, the PLA continues to retain its strength, which is not sufficient and this makes the bottom sheet more prone to rupture during use and detachment from the garment postuse.

[0003] Examples 2 and 3, consisting of a bilayer structured bottom sheet (18 and 24 GSM, respectively), demonstrated maximal durability of 12 hours, attributed to the barrier and basis weight of the PLA layer. However, the same issue persists and makes the bottom sheet more prone to rupture during use and detachment from the garment post-use, the brittle nature of PLA. Examples 4 through 11, employing a multilayer composite structure incorporating a PLA moisture-barrier layer (420), exhibited enhanced structural stability and performance (12 hours durability). This improved performance is ascribed to the efficacy of the PLA moisture-barrier layer (420) in obstructing moisture penetration to the underlying PVOH layer, thereby preserving the PVOH's strength. The combination of the PLA moisture-barrier layer (420), PVOH layer and the reinforcing layer (510) contributes to the improved durability.Flushability:

[0004] The flushability of all the hydro-degradable fluid absorbent (from Examples 1 to 14) is compared in Table 18.Table-18

[0005] All the hydro-degradable fluid adsorbent passed the Toilet bowl clearance, Drainline clearance and disintegration criteria as mentioned in paragraphs [000155], [000159] and [000164],

[0006] The comparative analysis of the hydro-degradable fluid absorbent materials indicates that the multi-layer composite structures (Examples 4-11) exhibit overall superior performance metrics compared to the bilayer structures (Examples 1-3). The data reveals that the MVTR of the bottom sheet comprising a bilayer structure range between 150-200 g / m2 / 24h, which is comparable to the MVTR of the bottom sheet comprising a multi-layer composite structure. This similarity in MVTR values can be attributed to the inclusion of the PLA moisture -barrier layer (420), whose high moisture -barrier efficacy results in reduced MVTR values. However, despite the similarity in MVTR values, the bilayer structure demonstrates lower elongation at break, that can lead to rupture of the bottom sheet both during usage and upon detachment after application.

[0007] The difference in elongation at break between the bilayer and multi-layer composite structures are significant. The multi-layer composite structure, with its higher elongation at break (Example 11 having 270% higher elongation than Example 3), effectively mitigates the inherent brittleness and noise characteristics of PLA, while introducing a degree of elasticity that enhances stability and comfort both during use and during removal from the garment.

[0008] In terms of durability, Example 12, which consist of cold-water soluble PVOH layer fails immediately when exposed to synthetic blood. This characteristic improves significantly by using a PLA moisture -barrier layer (420) underneath the PVOH layer (Examples 1 through 3). Examples 2 and 3, which consist of a bilayer structured bottom sheet (18 and 24 GSM, respectively), achieve a maximum durability of up to 12 hours, attributable to the PLA layer's barrier properties and basis weight. However, under dynamic condition the inherent brittleness of PLA can still compromise the bottom sheet's integrity, making it more prone to rupture during use and during detachment from the garment after use. Conversely, in Example 10, which employ a multi-layer composite structure incorporating a PLA moisture-barrier layer (420) able to overcome this challenge. This performance is due to the PLA moisture-barrier layer's (420) efficacy in impeding moisture penetration to the underlying PVOH layer, thereby preserving thePVOH's mechanical integrity. The synergistic combination of the PLA moisture -barrier layer (420) and the PVOH layer contributes to the observed durability under both static and dynamic conditions. The multi-layer structure effectively mitigates the limitations of the bilayer structure, including the brittleness and noise characteristics of PLA. As a result, it prevents the rupture during use and detachment from the garment, thereby establishing itself as a superior candidate for application.

[0009] In view of the present disclosure, which describes the present invention, all changes, modifications and, variations within the meaning and range of equivalency are considered within the scope of the invention. It is to be understood that the aspects and embodiment of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiment may be combined together to form a further embodiment of the disclosure.

Claims

WE CLAIM:

1. A hydro-degradable fluid absorbent comprising: a. a top sheet (110) comprising a hydro-degradable layer; b. an absorbent core (120) optionally comprising super absorbent polymer (SAP); c. a bottom sheet (130) comprising a multi-layer composite structure of one or more moisture barrier layer / s (420) and / or one or more water-soluble layer / s, (610), wherein at least one moisture-barrier layer (420) is sandwiched between two or more water-soluble layers (610); optionally attached to a reinforcing layer (510); and the bottom sheet (130) comprises a position adhesive (210) to stick to the garment.

2. A hydro-degradable fluid absorbent comprising: a. a top sheet (110) comprising a hydro-degradable layer; b. an absorbent core (120) optionally comprising super absorbent polymer (SAP); c. a bottom sheet (130) comprising a multi-layer composite structure consisting of one moisture-barrier layer (420) and one water-soluble layer (610); attached to a reinforcing layer (510) using a water-soluble adhesive; and the bottom sheet (130) comprises a position adhesive (210) to stick to the garment.

3. A hydro -degradable fluid absorbent as claimed in claim 1-2, wherein the hydro- degradable layer of the top sheet (110) is made of flushable fibers selected from a group of wood pulp, viscose fibers, other similar fibers, having basis weight in the range of 40-80 gram per square meter (GSM), The absorbent core (120) optionally with the SAP has basis weight in the range of 100-700 GSM., and the multi-layer composite structure of the bottom sheet (130) has a total basis weight in the range of 15 to 200 GSM.

4. The hydro-degradable fluid absorbent as claimed in claims 1-2, wherein the moisturebarrier layer (420) comprises materials selected from a group consisting of Polylactic acid (PLA), Polyhydroxy alkanotes (PHAs) and its derivatives poly (3- hydroxybutyrate) (PHB), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-4- hydroxybutyrate) (PHBH); Polyglycolic acid (PGA),Polypropylene carbonate (PPC), Polycaprolactones (PCL), and Polybutylene succinate (PBS) or blends thereof.

5. The hydro-degradable fluid absorbent as claimed in claim 1-2, wherein the water- soluble layer (610) comprises material selected from a group consisting of Partially hydrolyzed polyvinyl alcohol (PVOH), Hydroxypropyl cellulose, Polyethylene oxide (PEO), Polypropylene oxide (PPO), Polyvinylpyrollidone, Polyvinyl pyridine, Acrylic acid copolymers, Gelatinized starch, Interpenetrated networks of starch with ethylene / vinyl alcohol copolymers, Nylon copolymers, Polyethylene glycol (PEG), and Polyacrylamides, and Carboxymethyl cellulose, or blend thereof.

6. The hydro-degradable fluid absorbent as claimed in claims 1, 2, 4 and 5, wherein the moisture-barrier layer (420) is Polylactic acid (PLA) and the water-soluble layer (610) is Partially hydrolyzed polyvinyl alcohol (PVOH), wherein the PLA layer has basis weight of 3 to 40 GSM and PVOH layer has basis weight of 1 to 40 GSM.

7. The hydro-degradable fluid absorbent as claimed in claim 6, wherein the Partially hydrolyzed polyvinyl alcohol (PVOH) and Polylactic acid (PLA) layer, each preferably has 5 to 20 GSM.

8. The hydro-degradable fluid absorbent as claimed in claims 1-7, wherein the bottom sheet (130) is constructed in a way such that the water-soluble layer (610) or the moisture-barrier layer (420) is towards the absorbent core (130) and moisture-barrier layer (420) or other water-soluble layer (610) or reinforcing layer (510) is towards the garment side.

9. The hydro-degradable fluid absorbent as claimed in the claims 1-8, wherein the multilayer composite structure of bottom sheet (130) is optionally bound to a reinforcing layer (510).

10. The hydro-degradable fluid absorbent as claimed in claim 9, wherein the reinforcing layer (510) is bonded to the multi-layer composite structure of the bottom sheet (130) using water-soluble adhesive (410) or by industrial bonding techniques, such as coextrusion, thermal bonding, hot melt adhesives, and ultrasonic welding.

11. The hydro-degradable fluid absorbent as claimed in claims 9-10, wherein the reinforcing layer (510) is selected from spunlace non-woven sheet, paper or bio-based webs made up of wood pulp, other fibers.

12. A method of manufacturing a hydro -degradable fluid absorbent comprising: assembling a) a top sheet (110) comprising a hydro-degradable layer, b) an absorbent core (120) optionally comprising super absorbent polymer, c) a bottom sheet (130) comprising a multi-layer composite structure of one or more moisture barrier layer / s (420) and / or one or more water-soluble layer / s (610), wherein at least one moisturebarrier layer (420) is sandwiched between two or more water-soluble layer / s (610), optionally attached to a reinforcing layer (510); using one or more industrial bonding techniques.

13. The method as claimed in claim 12, wherein the said industrial bonding techniques are selected from coextrusion, thermal bonding, hot melt adhesives, water soluble adhesives, ultrasonic welding, and combination thereof.

14. The method as claimed in claim 1, wherein the multi-layer composite structure of the bottom sheet (130) can be manufactured using coextrusion, adhesive lamination, thermal lamination, ultrasonic bonding, coating, etc. and combination thereof.

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