Nitrite-detecting disposable absorbent hygiene article and manufacturing process thereof

Abstract

The present invention refers to a disposable absorbent hygiene article with high sensitivity to nitrites that comprises a nitrite indicator hot-melt adhesive (5) that detects nitrites in urine. The disposable absorbent hygiene article of the present invention is comprised of an inner layer or topsheet (1) comprising a non-woven, an acquisition distribution layer (ADL) (2), an absorbent core (3) comprising a super absorbent polymer (SAP) + fluff pulp, and an outer layer or backsheet (4) comprising a polyethylene or polypropylene film with a nitrite indicator hot-melt adhesive (5) which is applied in the inner side. The disposable absorbent hygiene article of the present invention is particularly but not exclusively, a diaper, an incontinence pad or a sanitary napkin.

Description

[0001] DESCRIPTION

[0002] NITRITE -DETECTING DISPOSABLE ABSORBENT HYGIENE ARTICLE AND MANUFACTURING PROCESS THEREOF

[0003] Field of the invention

[0004] The present invention relates to a disposable absorbent hygiene article that comprises a hot-melt adhesive, specifically to a disposable absorbent hygiene article that comprises a nitrite indicator hot-melt adhesive that detects nitrites in urine, in particular but not exclusively, a diaper, an incontinence pad or a sanitary napkin. Additionally, the invention relates to the manufacturing process of said disposable absorbent hygiene article .

[0005] Background of the invention

[0006] Urine is an aqueous solution secreted by the kidneys composed by more than 95% of water. The remaining components of healthy urine are urea, chloride, sodium, potassium, creatinine, and dissolved ions .

[0007] There are several physiological parameters that change in the presence of a urinary tract infection, such as the change in colour, clarity, odour, and / or pH of urine, as well as the possible presence of proteins, nitrites, ketones, glucose, and / or blood cells in urine. From these components, the presence of nitrites can be used to detect a urinary tract infection as the bacteria that causes the infection produces nitrate reductases, enzymes that convert nitrates into nitrites. The presence of nitrites in urine is commonly used as a marker for bacterial urinary tract infections (UTIs) , particularly those caused by Gram-negative bacteria, like Escherichia coli (E. coli) , which are the most common cause of UTIs. However, the detection of nitrites is not 100% sensitive for diagnosing UTIs.

[0008] Nitrite tests are highly specific but not as sensitive. This means that when nitrites are present, it is a strong indication of a UTI, but many patients with UTIs may not have detectable nitrites. The specificity of nitrites for UTI is often greater than 90%. If nitrites are detected, it is very likely the patient has a UTI. However, the sensitivity of nitrites is around 50% to 60%, meaning about 40% to 50% of patients with a UTI will have a false negative for nitrites .

[0009] The sensitivity of nitrites for detecting UTIs is not perfect as described because of three reasons. The first reason is the bacteria type: some bacteria, especially Gram-positive bacteria like Staphylococcus saprophyticus (bacteria that also causes UTIs) and Enterococcus, do not reduce nitrates to nitrites, leading to false negatives. The second reason for the level of sensitivity is the urine retention time: for nitrites to form, urine needs to be in the bladder for at least 4 hours. Frequent urination or diluted urine can lead to lower nitrite levels. Finally, the third reason for the level of sensitivity of nitrites is the diet and hydration level of patients, meaning that some dietary factors and excessive hydration can dilute urine, reducing the concentration of nitrites .

[0010] Urine samples are commonly analysed using urine test strip reader and urine sediment analysers. A urine test strip reader is an analyser that performs a chemical analysis of the urine by using test elements as known in the art. An example of a test element is the Combur-Test strips manufactured by Roche Diagnostics Ltd. The chemical analysis can include such tests as measuring the pH of the urine but can also be used to detect the presence of specific types of cells or metabolites in the urine, such as nitrites. The Combur-Test strips, reveal that the limits for detecting nitrites are 0,3 to 0, 9 mg / L, with a confidence of positive results of 100% and negative results of 100%. According to medicine leaflets about urinary dipsticks, the lower limit for detecting nitrites starts at 0,3 mg / L .

[0011] The dipsticks use a colour change reaction based on the Griess reaction, where the presence of nitrite in urine converts the chemically treated reagent area to a pink or red colour, depending on the concentration of nitrite.

[0012] The utility model document CN214967755U relates to diapers capable of detecting urine, in which the urine detection layer in the form of a strip or the urine detection layer in other forms is arranged on a PE bottom film, the urine detection layer is replaced by the detection test paper or the detection hot-melt adhesive, and the colour of the urine detection layer is detected by the detection filter paper or the detection hot-melt adhesive through the urine. Therefore, according to the change of the colour, it can be seen whether the corresponding symptoms of the user are normal.

[0013] Absorbent disposable hygiene articles, particularly diapers, are produced in highspeed machines, and usually comprise an outer layer called the backsheet, made of polyethylene or polypropylene film, an absorbent core comprising a super absorbent polymer (SAP) , often combined with fluffed wood pulp, so that SAP crystals can absorb and retain large amounts of liquid, transforming it into a gel, and the wood pulp acts as a supporting structure, an acquisition distribution layer (ADL) between the top layer (contacting skin) and the core material, helping for an even distribution of fluids thru the core, an inner layer contacting with the skin (topsheet) made from non-woven fabrics like polypropylene, elastic bandsor leg cuffs along the leg openings, which create a snug fit to prevent leaks, often made from spandex or elastomeric fibres, fastening system, usually refasten able tabs made from hook-and- loop fasteners or adhesive tapes, an elastic waistband that provides stretch and ensures a secure fit around the waist to prevent leaks while maintaining comfort, a barrier leg cuffs, a secondary set of barriers around the legs designed to provide an extra layer of leak protection by sealing off any gaps and wetness indicator adhesive. Some diapers include a wetness indicator strip, usually a chemical-sensitive material that changes colour when the diaper is wet, signalling when it needs to be changed.

[0014] The patent document EP4181978 relates to a hot-melt adhesive for personal hygiene disposable articles with the ability to detect the presence of analytes in urine, indicative of urinary tract pathologies. The hot melt adhesive comprises the Griess-Llosvay nitrite detection reagent.

[0015] By incorporating such reagent in the hot-melt adhesive composition, the hot-melt adhesive will change its colour in the presence of the analyte. Therefore, a possible urinary tract complication is detected, allowing for earlier treatments to begin .

[0016] Griess-Llosvay reagents mainly comprise a first reagent and a second reagent. The first reagent can be selected from, but not exclusively, N- ( 1-naphthyl ) ethylenediamine dihydrochloride and alpha-naphthylamine . The second reagent can be selected from, but not exclusively, sulfanilamide in phosphoric acid, sulfanilic acid, nitroaniline and p- aminoacetophen .

[0017] The detection of nitrite ions involves two subsequent reactions: when the second reagent is added to a solution with nitrites, it reacts with a nitrite molecule, forming a diazo (R2C-N=N) complex that is colourless. Such example of a diazo complex is the nitritesulf anilic acid complex. Only then, the diazo complex reacts with the first reagent to obtain a precipitate with red or pink colour. The higher the concentration of nitrites, the stronger the colour. This precipitate can also be referred to as azo dye or azo compound, due to the presence of an azo group (R-N=N-R' ) in the precipitate molecule.

[0018] Standard hot-melt application systems for conventional hot melts do not provide protection against oxidation of sensitive materials like the reagents described in the Griess-Losvay reaction. On the other hand, hot-melt equipment used for hot-melt reactive systems allow a protection against thermal degradation / oxidation of the mentioned reagents.

[0019] Advantages of the invention

[0020] The disposable absorbent hygiene article of the present invention increases the sensitivity of detecting nitrites in urine, making it a significant advance for diagnosing urinary tract infections (UTIs) . Nitrites in urine are a direct indicator of the presence of certain bacteria that convert nitrates, naturally present in urine, into nitrites. Normally, this conversion only takes place if bacteria are present, which makes nitrites a more specific marker of bacterial UTIs than leucocytes. Leucocytes can be present in the urine for various reasons, including inflammation unrelated to bacterial infection.

[0021] The present invention relates to a disposable absorbent hygiene article with high sensitivity to nitrites.

[0022] The disposable absorbent hygiene article of the present invention can provide more accurate, timely and reliable indications of bacterial UTIs and is particularly valuable in hospital settings or for individuals at higher risk of recurrent urinary tract infections, allowing faster intervention and potentially reducing complications related to UTIs.

[0023] The disposable absorbent hygiene article of the present invention comprises a nitrite indicator hot-melt adhesive (5) . The disposable absorbent article of the present invention has a set of parameters that allow it to detect nitrites with greater sensitivity, being able to react immediately to a first urination event, showing the correct sensitivity, but at the same time being able to receive and continuously detect nitrites over several urination events. This is particularly useful for patients who may not produce detectable nitrites levels in a single sample due to factors such as frequent urination or diluted urine.

[0024] The manufacturing process of the disposable absorbent hygiene article of the present invention allows the production of a disposable absorbent article, in particular but not exclusively, a diaper, an incontinence pad or a sanitary napkin that has a higher sensitivity to nitrites, but which only responds when a certain threshold of nitrites is reached, minimising any minor reactions that may occur due to trace amounts of nitrites that do not necessarily indicate an infection, reducing false positives.

[0025] Additionally, the manuf cturing process of the of the disposable absorbent hygiene article of the present invention comprises extremely low hot melt adhesive application temperatures on the article, using a drum melter, hose, and applicator that creates an oxygen-free atmosphere that preserves the nitrite indicator hot- melt adhesive.

[0026] Brief Description of the drawing

[0027] With reference to the attached schematic drawing, an illustrative and non-limiting embodiment of the absorbent disposable hygiene article according to the invention is described in more detail below .

[0028] Figure 1 shows a schematic of the functional layers of the absorbent article of the present invention.

[0029] The absorbent disposable hygiene article of the present invention is comprised of an inner layer or topsheet (1) comprising a nonwoven, an acquisition distribution layer (ADL) (2) , an absorbent core (3) comprising a super absorbent polymer (SAP) + fluff pulp, and an outer layer or backsheet (4) comprising a polyethylene or polypropylene film with a nitrite indicator hot-melt adhesive (5) which is applied in the inner side. Detailed description of the invention

[0030] The object of the present invention is a disposable absorbent hygiene article, in particular a disposable absorbent hygiene article that detects nitrites in urine, more specifically a disposable absorbent hygiene article that detects nitrites with high a sensitivity to nitrites.

[0031] In addition, another object of the present invention is the process of manufacturing the disposable absorbent hygiene article.

[0032] The disposable absorbent hygiene article of the present invention is particularly but not exclusively, a diaper, an incontinence pad or a sanitary napkin.

[0033] By "analyte" is meant any biochemical compound excreted through the urine that is associated with a pathology, such as nitrite, glucose, proteins and other such compounds.

[0034] By "high sensitivity to nitrites" is meant the detection of nitrites in solutions with a nitrite concentration equal to or greater than 0,2 mg / L.

[0035] "Nitrite indicator hot-melt adhesive" refers to a hot-melt adhesive that comprises a nitrite indicator. This indicator reacts when it comes into contact with nitrites, such as those present in urine, which can be useful for detecting health conditions.

[0036] By "backsheet" is meant the polyethylene or polypropylene film substrate of the outer layer of the disposable absorbent hygiene article . By "topsheet" is meant an inner layer of the disposable absorbent hygiene article.

[0037] By "substrate" is meant the material or the material surface in which the hot melt adhesive is applied and / or contacts directly with the material .

[0038] By "extremely low hot melt adhesive application temperatures" is meant a temperature of up to 90 °C, preferably between 80 °C and 90 °C.

[0039] By "front side of the disposable absorbent hygiene article" is meant the section that faces the front of the user's body.

[0040] By "urination region" is meant a region that is affected at the time of micturition (urination) by the user.

[0041] The absorbent disposable hygiene article of the present invention is comprised of an inner layer or topsheet (1) comprising a nonwoven, an acquisition distribution layer (ADL) (2) , an absorbent core (3) comprising a super absorbent polymer (SAP) + fluff pulp, and an outer layer or backsheet (4) comprising a polyethylene or polypropylene film with a nitrite indicator hot-melt adhesive (5) which is applied in the inner side.

[0042] The nitrite indicator hot-melt adhesive (5) comprises a Griess-

[0043] Llosvay nitrite detection reagent.

[0044] According to the present invention, when a person urinates, if bacterial infection is present in the urine, then the nitrite in the urine reacts with the Griess-Llosvay reagent. As a result of the reaction, a pink or red colour change occurs that can be easily recognised from the outer surface of the disposable absorbent hygiene article. The presence of the colour change is a positive indicator in understanding the presence of infection.

[0045] In a preferred embodiment, the nitrite indicator hot-melt adhesive (5) present in the disposable absorbent hygiene article, goes from white to red or pink, and the colour intensity depends on the concentration of the analyte being analysed.

[0046] The disposable absorbent hygiene article of the present invention is sensitive to nitrites at a concentration equal to or greater than 0 , 2 mg / L .

[0047] The disposable absorbent hygiene article of the present invention has high sensitivity to nitrites due to the combination of the following parameters:

[0048] - nitrite indicator hot-melt adhesive areas; amount of nitrite indicator hot-melt adhesive; and super absorbent polymer (SAP) / Fluff pulp ratio.

[0049] Nitrite indicator hot-melt adhesive areas

[0050] In a preferred embodiment, nitrite indicator hot-melt adhesive (5) is applied to the inner side of the backsheet (4) of the disposable absorbent hygiene article in at least one line with dimensions from 0,005 m to 0,05 m width and 0,01 m to 0,3 m length, preferably 0,01 m to 0,02 m width and 0,05 m to 0, 1 m length. The amount of nitrite indicator hot-melt adhesive

[0051] In a preferred embodiment, the amount of nitrite indicator hot- melt adhesive (5) on the disposable absorbent hygiene article is between 0,05 kg / m2and 0,3 kg / m2, preferably between 0, 1 kg / m2and 0, 15 kg / m2.

[0052] Super absorbent polymer (SAP) / Fluff pulp ratio

[0053] In a preferred embodiment, the disposable absorbent hygiene article of the present invention comprises of an SAP / Fluff pulp ratio between 0 / 100 and 80 / 20, preferably from 30 / 70 to 50 / 50.

[0054] Embodiments of the invention

[0055] To verify the nitrite detection results obtained with the combination of the amount and areas of nitrite indicator hot-melt adhesive and the SAP / fluff pulp ratio present in a disposable absorbent hygiene article. The combinations of these three parameters were studied and compared with Combur-Test strips manufactured by Roche Diagnostics Ltd.

[0056] This invention is further illustrated by the following nonlimiting examples .

[0057] The method for detecting the concentration of nitrites consisted of introducing solutions with different concentrations of nitrites into the topsheet (1) of the disposable absorbent hygiene article that comprises a nitrite indicator hot-melt adhesive (5) , and checking the colour change from beige to pink, and in which the colour change occurs in an interval between 1 and 20 minutes. In Example 1 are presented the results of a Combur-Test strips manufactured by Roche Diagnostics Ltd. These strips only detect nitrites when they are present at a concentration of 0,5 mg / L.

[0058] In Examples 2 to 13 show the nitrite detection results for a disposable absorbent hygiene article comprising different ratios of SAP / Fluff pulp and different amounts of nitrite indicator hot- melt adhesive (5) .

[0059] Example 2, Example 4, Example 5, Example 7, Example 8 and Example 10 shown in Table 1 correspond to the disposable hygiene article of the present invention.

[0060] The results obtained show that the disposable absorbent hygiene article of the present invention has greater accuracy and sensitivity when it comes to detecting nitrites at lower concentrations, such as 0,2 mg of nitrite / L compared to the Combur- Test strips manufactured by Roche Diagnostics Ltd.

[0061] It can be verified that the disposable absorbent hygiene article of the present invention achieves a detection rate of 100% for both 0,5 mg of nitrites / L and 0,2 mg of nitrites / L, while known and common devices, such as urinary strips, do not detect concentrations of less than 0,3 mg of nitrites / L.

[0062] In addition, the results show that the cumulative absorption of nitrites by the nitrite indicator hot-melt adhesive reveals a 100% absence of detection for a low concentration nitrite solution with a concentration of 0,01 mg nitrite / L, which confirms that the disposable absorbent hygiene article of the present invention does not contribute to the potential creation of false positives relating to traces of nitrites. Table 1

[0063] Caption :

[0064] (1)Results based on 100 trials in which the 2 x 150 ml of nitrite solutions are introduced in disposable absorbent hygiene article with a core in a large heavy incontinence product.

[0065] (2)Results based on 100 trials in which 3 x 150 ml of nitrite solutions are introduced in the topsheet (1) of the diaper over a 4 hour period in a large heavy incontinence product.

[0066] (3) The urine test strip has been dipped in the nitrite solution and the result is checked between 1 and 2 minutes, according to the manufacturer's instructions.

[0067] Disposable absorbent hygiene article manufacturing process

[0068] The manufacturing process for the disposable absorbent hygiene article of the present invention comprises the following steps: a) the nitrite indicator hot-melt adhesive (5) is applied to the inner side of the backsheet (4) of the disposable absorbent hygiene article, in at least one line with dimensions from 0,005 m to 0,05 m width and 0,01 m to 0,3 m length, preferably 0,01 m to 0,02 m width and 0,05 m to 0, 1 m length; and b) the disposable absorbent hygiene article is packed under a vacuum in an opaque bag. Vacuum filling allows the good stability of the nitrite indicator hot-melt adhesive. For the best accuracy of the nitrite indicator hot-melt adhesive (5) and avoidance of bacterial contamination from faeces which could cause false nitrite positive results, the nitrite indicator hot-melt adhesive (5) is applied in the inner side of the backsheet (4) , on front side of the urination region of the disposable absorbent hygiene article.

[0069] In a preferred embodiment, the nitrite indicator hot-melt adhesive (5) is applied by spray coating or other topical applications, preferably by slot coating.

[0070] In order to preserve the nitrite indicator hot-melt adhesive (5) properties and to obtain a stable and uniform application of the nitrite indicator hot-melt adhesive (5) , the nitrite indicator hot-melt adhesive (5) is applied at a temperature of up to 90 °C, preferably between 80 °C and 90 °C, using a drum melter, hose and nozzle, capable to keep the adhesive under a protected oxygen-free environment .

[0071] In a preferred embodiment, the disposable absorbent hygiene article is packed inside an aluminium and polyethylene (PE) bag or other materials such as a variety of plastics that are completely opaque, which are not permeable to oxygen, humidity and light and a allow that the contents remain sealed under vacuum.

[0072] In another preferred embodiment, the disposable absorbent hygiene article is packed under a non-resealable or a resealable bag, preferably a resealable bag.

[0073] Many modifications and variations of this invention can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. The specific embodiments described herein are offered by way of example only, and the invention is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

CLAIMS1. Nitrite-detecting disposable absorbent hygiene article comprising an absorbent core comprising a topsheet (1) , an acquisition distribution layer (ADL) (2) , an absorbent core (3) comprising a super absorbent polymer (SAP) + fluff pulp, and a backsheet (4) comprising a polyethylene or polypropylene film with a nitrite indicator hot-melt adhesive (5) characterized in that the disposable absorbent hygiene article comprising the nitrite indicator hot-melt adhesive (5) on at least one line with dimensions from 0, 01 m to 0,02 m width and 0,05 m to 0, 1 m length, the amount of nitrite-indicator hot- melt adhesive (5) on the disposable absorbent hygiene article is between 0, 1 kg / m2and 0, 15 kg / m2and SAP / fluff pulp ratio is from 30 / 70 to 50 / 50.

2. Nitrite-detecting disposable absorbent hygiene article according to the previous claim, wherein the nitrite indicator hot-melt adhesive (5) is on the inner side of the backsheet (4) .

3. Nitrite-detecting disposable absorbent hygiene article according to the previous claim, wherein the nitrite indicator hot-melt adhesive (5) is on the inner side of the backsheet (4) , on front side of the urination region of the disposable absorbent hygiene article.

4. Nitrite-detecting disposable absorbent hygiene article according to the previous claims, wherein the nitrite indicator hot-melt adhesive (5) comprises a Griess-Llosvay nitrite detection reagent.

5. Nitrite-detecting disposable absorbent hygiene article according to the previous claims, wherein the topsheet (1) comprises a non-woven.

6. Nitrite-detecting disposable absorbent hygiene article according to the previous claims, where in the disposable absorbent hygiene article is a diaper, an incontinence pad or a sanitary napkin.

7. A manufacturing process of the nitrite-detecting disposable absorbent hygiene article claimed in any of the previous claims, characterized by comprising the following steps: a. the nitrite indicator hot-melt adhesive (5) is applied to the inner side of the backsheet (4) at a temperature of up to 90 °C, using a drum melter, hose and nozzle in an oxygen-free environment; and b. the disposable absorbent hygiene article is packed under a vacuum in an opaque bag.

8. The manufacturing process according to the previous claim, wherein the nitrite indicator hot-melt adhesive (5) is applied by slot coating.

9. The manufacturing process according to claim 7, wherein the bag is an aluminium and polyethylene (PE) bag.

10. The manufacturing process according to any of the claims 7 or9, wherein the bag is a resealable bag.

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