In ! uence of some Structural Properties of Incontinence Diapers on their Functionality

Incontinence aff ects millions of people all over the world; however, it is more common in women overall. The urinary incontinence is common, especially in old age. Several statistics indicate that 5–10 percent of all people are aff ected by urinary incontinence, two thirds of them being over the age of 60. Based on the abovementioned facts, the presented research focuses on multilayer nonwoven textiles for incontinence diapers, especially on their functionality during wearing and using. The investigated incontinence diapers consist of three layers. The upper layer is made of PP spunbond nonwovens. The second, inner part of the diaper consists of cellulose pulp that contains a super absorber polymer (SAP). The third, last layer consists of a polymer-coated spunbond PP nonwoven that is fastened to the underwear with an adhesive strip and protected with a paper prior to the use. In the research, the elastic recovery after compression loading, water vapour transmission, absorbency, bending rigidity and pore size of incontinence diapers from two diff erent producers off ered by Sanolabor, d. d., were analysed and compared. The results of the research show that sample A 10 with the highest mass and thickness, and the lowest diameter of fi bres (consequently with the highest number of pores in cellulose pulp (absorptive core) and in the fi rst layer from PP fi bres) expresses the highest water vapour transmission and absorbency, mainly due to the highest number of pores on the sample.


Introduction
More than 25% of female population occasionally face incontinence in their lives.One of the reasons for incontinence in women is the weakening of muscles that occurs during pregnancy and a er giving birth.About 4% of men experience incontinence; however, with age, the number rises to 17%.Male incontinence is o en associated with prostate.Incontinence a ects millions of people all over the world, but it is overall more common in women.e urinary incontinence is common, especially in old age.Various statistics indicate that urinary incontinence a ects 5-10% of all people, two thirds being over the age of 60 [1][2][3].Incontinence diapers are made of two layers produced with the spunlaid process and are thermobonded ( rst and protective layer) in the so-called spunbond process.e rst layer presents about 10% of the total mass of the diaper and is in many cases produced from PP or PE bres.e inner part (absorptive core) of the diaper consists of cellulose pulp from very short cellulose bres (less than 4 mm in length) and a super absorber polymer (SAP).e cellulose pulp presents about 64% of the total mass of the diaper.e super absorber polymer (SAP) absorbs liquid to up to about 300-times according to its weight.e super absorber polymer (SAP) is produced with the polymerisation of acrylic acid to polyacrylic acid that is in a further process neutralised with sodium hydroxide.SAP is found dispersed into the u in the form of a white, granular solid.SAP can hold up to about 20-30 times its mass of urine.
e rst technological process in the production of nonwovens is the web formation to form a web from staple bres or laments.e orientation of bres in the web is either longitudinal (anisotropic), accidental (isotropic) or cross-directed [7][8][9].
e spunbond (extruded) web formation and thermal bonding include the following major elements of the process: Preparation of polymer melt in extruder.

•
Spinning: e melt passes through the porous l-• tration layer, arrives at the spinneret nozzle with a high degree of homogeneity and is ideally suited for the spinning process.e spinneret usually consists of a perforated plate arranged across the width of the line.e resin is forced through the many small holes in the spinneret plate to form continuous laments, using cooling with air.Drawing the laments in an attenuation zone that • [7].Nonwovens that are produced from staple bres or laments to form a web that is nally bonded by di erent bonding techniques play an important role in the medical textile production.Medical textiles (Medtech) represent an important part of technical textiles.From the documents that are published by the European organisation EDANA, which covers the eld of nonwovens [6], is can be seen that the nonwovens for hygiene products present around 32% of today's market, while the nonwovens for medical textiles present around 3% of the market.
e research of medical textiles became nowadays very important and is relatively new.Due to the above written facts, several researches have been presented in the literature in the last few years.
e research by the authors Das, D. et al entitled Liquid Sorption Behavior of Superabsorbent Fiber Based Nonwoven Media from 2013 [10] deals with the absorption of nonwovens from superabsorbent bres.In the last few years, many researches were dealing with the relation between the bre diameter, pore size of the nonwoven fabric and the ability of absorption [11][12][13][14][15][16].In the last four years, many researches have dealt with nonwoven products for hygiene that contain the super absorbent polymer (SAP) [11][12][13][14][15][16].Since its development in the late 1970s and early 1980s, the use of SAP has revolutionised the diaper industry as diaper manufacturers soon began to on their Functionality Tekstilec, 2016, 59(4), 298-310 design diapers that were thinner, more absorbent and comfortable than ever before [17].Early SAP-containing diapers contained only one to two grams of the material, whereas its weight increased to the mass of 15-16 grams per diaper as the amount of u pulp diminished -some modern diapers have virtually no u pulp at all [17].

Compression behaviour of incontinence diaper
Since incontinence diapers consist of three layers, where one of the layers presents the cellulose pulp from short bres and a super absorbent polymer, the comfort properties besides their functionality are very important as well, e.g.compression behaviour during wear and elasticity.e elasticity of incontinence diapers refers to the elastic recovery (E e ) of the sample to the thickness or height prior to the loading.e height of the sample is marked in that case as h 0 , while the height of the sample a er the compression loading and time of relaxation 1 min is marked as h 1 .Elastic recovery is determined as the di erence between the height of the sample prior to and a er the loading (h 0 -h 1 ), related to the height of the sample prior to the loading (h 0 -h 1 /h 0 ) and is expressed in percentage [18].

Absorption of incontinence diaper
e main property of incontinence diapers is their absorbency.Absorbency depends on the structural properties of incontinence diapers (mass, thickness, characteristics of bres).A thicker diaper usually has a higher absorbency rate.From the structural properties, the type, diameter and bre length, as well as the diameter and number of pores in the nonwoven web (diaper) are important as well.inner bres also ensure a higher surface contact, higher number of contact points between the bres in the web, and consequently the friction between bres, which prevents the absorption of liquid.
e diameter and the number of pores in uence the absorbency.e hydrophilic or hydrophobic polymer type of bres inuences the inherent absorbent properties of the nonwoven fabric.For example, cellulose bres that are mostly used as the inner layer have moisture regain of 13% and increase by length 3-5% when they are immersed into water, while the moisture regain of PE or PP bres equals zero percent.e nonwovens from PP and PE bres are mostly used as spunbond nonwovens, especially for the rst or last (protection) layer in incontinence diapers.Hydrophilic bres have the capacity to absorb liquid via bre imbibitions, giving rise to bre swelling.is also attracts and holds liquid external to the bre, in capillaries and structure voids.On the other hand, hydrophobicbres increase absorption according to their shape (round, trilobal etc), thickness and length.e bre linear density and its cross-section area a ect void volume, capillary dimensions and the total number of capillaries per unit mass in nonwoven fabrics which a ects the absorbency increase [14][15][16].Absorbency is determined in percentage as the di erence between the wet mass of a sample (a er absorption of liquid) and the dry mass of a sample [18].e absorbency of incontinence diapers mostly depends on cellulose pulp that represents about 64% of the total mass of the diaper.e cellulose pulp ller contains the super absorber polymer (SAP), which absorbs liquid to up to about 30 times of its weight [9].Based on the above-mentioned facts, the presented research focuses on multilayer nonwoven textiles used for incontinence diapers, especially their functionality during wear and end use.With the presented research, the incontinence diapers of two producers were analysed and compared.

Materials and methods
With the presented research, the incontinence diapers of two producers were analysed (o ered by the company for medical, pharmaceutical and laboratory marketing, and distribution Sanolabor, d. d.).Sample A 10 is from the rst producer, while the samples I 9 and I 10+ are from the second producer -sample I 9 is intended for daily use, whereas sample I 10+ is intended for night-time use.Incontinence diapers consist of three layers.e upper layer is made of a nonwoven fabric produced from extruded web formation and is thermobonded, i.e. the so-called spunbond web formation.e upper layer consists of PP bres in the isotropic orientation, with the mass and thickness from 43.57 g/m 2 and 0.712 mm (sample A 10), to 70.92 g/m 2 and 0.543 mm (sample L 9), and 54.46 g/m 2 and 0.666 mm (sample I 10+).
e second, inner part of the diaper consists of cellulose pulp with very short cellulose bres with around 4 mm in length and contains the super on their Functionality Tekstilec, 2016, 59(4), 298-310 absorber polymer (SAP).e inner part of the diaper represents about 64% of the total mass of the diaper and functions as the ller of the diaper.e inner part of the diaper, with the pulp from very short cellulose bres and super absorber polymer, plays an important part in liquid (urine) absorption.e diameter of cellulose bres of the inner part of the diaper ranges from 29.38 µm (sample A 10) to 35.76 µm (sample I 9) (Table 1).SAP is dispersed into the cellulose pulp in the form of a white, granular solid, and can hold about 20-30 times its mass of urine.
e last layer is also made of a nonwoven produced from extruded web formation and is thermobonded.
e last layer is a protective layer with an adhesive application, which facilitates the attachment to a textile material (e.g.underwear).
e web of the last layer consists of PP bres in the isotropic orientation that is intended only for protection, preventing the passage of liquid (urine) from the diaper to the textile material (Figure 1).  1. Table 2 includes the photos of a cross-sectional and upper view of samples analysed in the dry and wet condition a er the wetting with 200 mL of distilled water, recorded during the determination of elastic recovery a er the compression loading analysis.
e SEM images of incontinence diapers are presented in Table 3.In the research of the functionality (elastic recovery a er compression loading, water vapour transmission, absorbency -MDS and Rothwell methods) and porosity of incontinence diapers from two different producers, the methods which are described below were used.

Elastic recovery a er compression loading
e elastic recovery of incontinence diapers was determined according to the modi cation of the method by ASTM D6571 -Standard Test Method for Determination of Compression Resistance and Recovery Properties of Highlo Nonwoven Fabric Using Static Force Loading [19].e elastic recovery, E e , a er compression loading was determined at an incontinence diaper in dry and wet condition.A er measuring the elastic recovery, E e , a er compression loading in dry condition, the specimen was poured with 200 mL of synthetic urine (0.9% NaCl solution).
e specimen was loaded to the maximum load of 40 N, which was chosen according to the MDS method (part 2 and part 3), where the wet sample was loaded with the weight of 4 kg for 10 minutes.During compression loading of the sample to the maximum load of 40 N (approx.4 kg), the height of the sample with the load of 40 N (h 1 ) was observed (loading time = 1 min).A erwards, the sample was relaxed (0 N; relaxation time = 1 min), and the controlled cycle was performed and the height of the relaxed sample was determined (h 2 ).Finally, the elastic recovery was calculated (Equation (1)). , where E e is elastic recovery a er compression loading in %, h 0 the height of the sample in the starting  .e sample dimensions were 2.5 cm × 25 cm in both directions (longitudinal and transversal).To determine bending rigidity, the mass of the sample, M, in g/m 2 was measured.Finally, bending length, c (cm), was calculated.Bending length presents a half of the length of the overhang, O (cm), of the specimen.e length of the overhang was measured on a cantilever tester at the angle of 41.5° and bending rigidity, G, in µN • m was determined in Equation (2).
where G is bending rigidity in µN • m, c bending length in cm and M mass per unit area in g/m 2 .

Water vapour transmission
Water vapour transmission was determined according to ASTM E96/E96M [21].e test specimen was sealed to the open mouth of a test dish with the diameter of 3 cm, containing 7 mL of water, the assembly being placed in a controlled atmosphere (T = 23 °C, RH = 50%).e sample was weighed a er one (m 1 ) and 24 hours (m 2 ) in a controlled atmosphere.Finally, the water vapour transmission (WVT) was calculated in g/m 2 h (Equation ( 3)).
where WVT represents water vapour transmission in g/m 2 h, m 1 mass of the sample a er one hour in a controlled atmosphere in g, m 2 mass of the sample a er 24 hours in a controlled atmosphere in g, A represents the area of the open mouth of a test dish with the diameter of 3 cm in m 2 and t the measuring time (24 hours) (h).
Absorbency according to MDS method (part 2 and part 3) e absorbency of incontinence diapers according to the method MDS, part 2 was determined on a sample with the dimensions 105 × 105 mm. e sample was covered by stainless steel plate with a round opening and thickness of 1 cm.Finally, the absorbency time of 5 mL of synthetic urine (0.9% NaCl solution) was determined with a stopwatch.e absorbency according to the method MDS, part 3 was determined using four layers of lter paper with the dimensions 100 × 100 mm, which was weighed.A erwards, 10 mL of synthetic urine was poured onto the sample.e wet sample was loaded with the weight of 4 kg for 10 minutes.A er that time, the lter paper was placed on the sample surface and loaded with the weight of 4 kg again for 2 minutes.Finally, the wetted lter paper was weighed again and the absorbency of water on the lter paper surface was determined.Higher absorbency on the lter paper surface also means a wetter diaper on the surface of the rst layer and higher mass of the liquid on the incontinence diaper surface [22].

Absorbency according to Rothwell method (ISO
e Rothwell method is based on the total absorbency of the liquid (synthetic urine).With this method, the dry diaper was weighed (m 1 ).e diaper was then immersed into a synthetic urine solution (0.9% NaCl solution) for 30 minutes.A er draining the diaper on a grid for 5 minutes, the wet diaper was weighed again (m 2 ).e absorbency was determined and expressed in percentage in Equation ( 4) [23].Porosity according to J-method e porosity (average diameter and number of pores) was determined according to the so-called J-method, which was elaborated by the research laboratory of the Department of Textiles, Graphic Arts and Design at the Faculty of Natural Sciences and Engineering under the leadership of Prof Jakšić, D. [24].
e method is based on selective squeezing out of the uid from the pores of wet fabrics with air pressure.We were able to estimate the porosity parameters such as the hydraulic diameter of pores, distribution of pores, the open area for the uid ow and the number of hydraulic pores.e parameters were estimated based on the measurement of air volume velocity through dry and wet samples as a function of air pressure.All measured data were fed into the computer program called PoreP [24], developed especially for that purpose.e whole procedure took about 20 minutes and the results obtained with this method were in good agreement with those gained optically. on their Functionality Tekstilec, 2016, 59(4), 298-310

Statistical analysis
e impact of multilayer hygiene nonwoven fabric structure on their functionality (elastic recovery, bending rigidity, water vapour transmission, absorbency) was tested using the analysis of variance (ANOVA) to determine the signi cance of multilayer hygiene nonwoven fabric structure on the elastic recovery, bending rigidity, water vapour transmission and absorbency.
e basis of the one-factor ANOVA is represented by the partitioning of sums of squares into betweenclass (SSb) and within-class (SSw). is technique enables all classes to be compared with each other simultaneously, rather than individually.is method also assumes that the samples are normally distributed.
e one-factor analysis is calculated in three steps.e sums of squares are rst determined for all samples, and then for the within-class and betweenclass cases.For each stage, the degrees of freedom (df) are determined as well, where df is the number of independent pieces of information involved in the estimate of a parameter.ese calculations are used with Fisher statistics to analyse the null hypothesis.
e null hypothesis states that there are no di erences between the means of di erent classes, suggesting that the variance of the within-class samples should be identical to that of the between-class samples.If F ≥ 1, then the di erences are likely to exist between the class means.ese results are then tested for statistical signi cance or p-value, where the pvalue is the probability that a variate assumes a value greater than or equal to the value observed strictly by chance.If the p-value is low (e.g.p ≤ 0.05 or p ≤ 5%), then the null hypothesis is rejected, indicating that di erences exist between the classes and that these di erences are statistically signi cant.If the p-value is greater than 0.05 (e.g.p ≥ 0.05 or p ≥ 5%), then the null hypothesis is accepted, indicating that the di erences between classes are accidental.[25] 3 Results and discussion

Results of elastic recovery after compression loading
e results of researching elastic recovery a er compression loading show that elastic recovery of incontinence diapers a er the loading with the load of 40 N, which corresponds to the weight of about 4 kg, is lower than 50% (Table 4).Incontinence diapers consist of three layers, the inside layer presenting cellulose pulp that in uences lower elastic recovery.
e lowest elastic recovery was determined at sample A 10 (37.2%), while samples I 10+ and I 9 expressed higher elastic recovery (from 42.0% to 43.1%).e results of elastic recovery after compression loading of samples I 10+ and I 9 show a very small di erence between sample I 10+, which is intended for daily use, and sample I 9, which is intended for night-time use.e reason for lower elastic recovery of sample A 10 lies in its highest mass (1661.6 g/m ) and thickness (10.48 mm).e statistical analysis ANOVA showed signi cant di erences in elastic recovery a er compression loading of the analysed dry samples (pvalue = 0.28).e results of elastic recovery a er compression loading were interesting a er wetting the samples with 200 mL of synthetic urine (0.9% NaCl solution) (Table 5).e results of researching elastic recovery a er compression loading show that sample A 10 expressed the highest elastic recovery in wet condition (40.2%).Samples I 10+ and I 9 expressed smaller elastic recovery in wet condition (28.9% and e results also showed that elastic recovery in wet condition of sample I 10+, which is intended for night-time use, amounted to 28.9%, which is between the values of sample A 10 and sample I 9. Sample A 10 had the lowest diameter of cellulosebres of the inner layer or absorbent core (29.38 µm, Table 1), and consequently higher speci c surface, and number of cellulose bres and pores of the absorbent core that a ect higher absorption.Based on the above mentioned facts about the absorption of hydrophilic bres, i.e. cellulose bres, it can be stated that a hydrophilic bre provides the capacity to absorb liquid via bre imbibitions, giving rise to bre swelling.It also attracts and holds liquid external to on their Functionality Tekstilec, 2016, 59(4), 298-310 the bre, in the capillaries and structure voids.Higher absorption increases the mass and thickness of sample A 10. Elastic recovery a er compression loading of an incontinence diaper in wet condition increases as well.
e statistical analysis ANOVA showed signi cant di erences in the elastic recovery a er compression loading of the analysed wet samples (p-value = 0.74).

Results of bending rigidity
e results of bending rigidity of the analysed incontinence diapers are in close connection with the mass and thickness of the samples speci ed in Table 1.Sample A 10 with the highest mass (1661.6 g/m 2 ) and thickness (10.48 mm) expressed also the highest bending rigidity (23587.04µN • m). e bending rigidity of sample A 10 was by about 50% higher than the bending rigidity of samples I 10+ and I 9, which have lower mass and thickness (Table 6).e incontinence diaper with the highest bending rigidity expressed lower exibility to the movements of the body while wearing the diaper.Sample I 10+, which is intended for night-time use, expressed due to higher thickness than sample I 9 (intended for daily use) also higher bending rigidity than sample I 9.
e statistical analysis ANOVA showed signi cant di erences in bending rigidity of the analysed samples (p-value = 0.49).

Results of water vapour transmission (WVT)
e water vapour transmission of the analysed incontinence diapers was moving at around 30 g/m 2 • h. is means that 30 mL of water vapour passes in one hour from the skin surface through one square meter (1 m 2 ) surface of an incontinence diaper to the environment.Incontinence diapers consist of three layers, the inner layer presenting the absorptive core from cellulose pulp and super absorber polymer (SAP) that also absorbs water vapour.at is the reason for a low value (30 g/m 2 • h) of water vapour which passes through the incontinence diaper surface.
e highest water vapour transmission was determined at sample A 10, which had the highest mass (1661.6 g/m 2 ) and thickness (10.48 mm), and the smallest diameter of cellulose bres in cellulose pulp (29.4 µm) and PP bres in the rst (upper) layer (16.8 µm).Sample A 10 had the highest number of pores in the upper layer (681 pores, with the average diameter of 125.29 µm) (Table 7).At samples I 10+ and I 9, the diameter was larger in cellulose bres in the cellulose pulp (around 35 µm) and PP bres in the rst (upper) layer (around 18 µm), as was larger the average diameter of pores in the upper layer (from 158.97 to 219.06 µm), whereas the number of pores was smaller (512 to 530 pores).e lowest diameter in cellulose bres in the cellulose pulp (29.4 µm) and in PP bres in the upper (top sheet) layer of the thickest incontinence diaper in uenced the highest number of pores (around 45%) with the average diameter of 125.29 µm at sample A 10. e latter increased the water vapour transmission of sample A 10 (30.3 g/m Sample I 10 + for night-time use had almost the same water vapour transmission as sample I 9, which is intended for daily use.

Results of absorbency according to MDS method (part 2 and 3)
e results of absorbency time of 5 mL of synthetic urine (MDS method, part 2) of the analysed incontinence diapers show that all samples had very short absorbency time required for the absorption of 5 mL of synthetic urine.e absorption time for all analysed samples was one second, which means that all incontinence diapers absorbed 5 mL of synthetic urine in only one second.Absorbency according to the method MDS, part 3 was determined with the absorption of synthetic urine by lter paper on a sample in wet condition (poured with 10 mL of synthetic urine), which was loaded with the weight of 4 kg.e wetted lter paper was weighed and the absorbency of water on the lter paper surface was determined.e highest absorption of lter paper was determined at sample A 10 (3.9%) which had the highest mass (1661.6 g/m 2 ), thickness (10.48 mm) and the lowest diameter of cellulose bres in the cellulose pulp (29.4 µm) and the lowest average diameter of pores (125.29 µm).Sample A 10 had the highest number of pores in the cross-sectional area of the sample (681 pores) with the smallest average diameter (125.29 µm).Higher absorbency on the lter paper of sample A 10 surface means lower absorbency in the inner part (absorbent core) of the incontinence diaper and a higher volume of synthetic urine on the surface of the incontinence diaper.e absorbency of the lter paper of samples I 10+ and I 9 in the wet condition was 3.2%, i.e. by 20% lower than the absorbency of the lter paper of sample A 10 in wet condition.While wearing an incontinence diaper, it is very important that the person retains the dry feeling, meaning that samples I 10+ and I 9, which expressed lower absorbency on the lter paper surface, had by about 20% dryer upper layer which is in contact with the skin during wearing, than sample A 10 (Table 8) and in this way proved better.Sample A 10 also had the smallest diameter of cellulose bres in the inner layer or absorbent core (29.38 µm), and consequently higher speci c surface and number of cellulose bres as well as the number of pores (681 pores) in the absorbent core, causing higher absorption of the diaper.Based on the above mentioned facts about the absorption of hydrophilic bres, higher absorbency of the lter paper on the surface of such a sample is expected.e statistical analysis ANOVA showed signi cant di erences in the absorbency of lter paper between samples I 9, I 10+ and A 10 (p-value = 0.50).e results of absorbency by the Rothwell method, which is based on the total absorbency with the immersion of the incontinence diaper into a synthetic urine solution (0.9% NaCl solution) for 30 minutes, show the highest absorbency at sample A 10 (492.5%).Sample A 10 absorbed 5 times its weight of synthetic urine.e absorbency of sample I 10+ amounted to 486.4%, while sample I 9 had the lowest absorbency (377.7%).Sample A 10 had the highest absorbency (492.5%)due to its highest mass (1661.6 g/m 2 ), thickness (10.48 mm) and the lowest diameter of cellulosebres in the cellulose pulp (29.4 µm), and consequently the highest number of pores (681 pores, average diameter 125.29 µm) in the cross-sectional area.e sample with the lowest absorbency, i.e. sample I 9 (377.7%),had the mass of 939.0 g/m 2 and thickness of 8.12 mm, and the highest diameter of cellulosebres in the cellulose pulp (35.8 µm).Sample I 9 is intended for daily use.e average pore diameter of sample I 9 was 158.97 µm; therefore, the main reason for lower absorbency lies in the smaller number of pores (512 pores with the diameter 158.97 µm) in the cross-sectional area of sample I 9.
e mass and thickness of sample I 10+ were 640.6 g/m 2 and 8.63 mm. e diameter of cellulose bres in the cellulose pulp was 33.3 µm.Sample I 10+ included 530 pores with the diameter 219.06 µm.e absorbency of sample I 10+ equalled 477.4 %, mainly due to cellulose pulp bres being thinner than at sample I 9 (Table 9).Sample I 10 + is intended for night-time use.e absorbency of analysed incontinence diapers depends on their Functionality Tekstilec, 2016, 59(4), 298-310 on the quantity of super absorber polymer (SAP) in the inner part of the diaper, which was impossible to weigh.It is expected that a thicker sample (e.g.sample A 10) can have a higher quantity of the super absorber polymer incorporated into its inner part (i.e.absorbent core).
e statistical analysis ANOVA showed signi cant di erences in the absorbency (Rothwell method) of the analysed samples (p-value = 0.46).e absorbency of the lter paper on the surface • of the incontinence diaper was also the highest at sample A 10.At incontinence diapers with thicker cellulose pulp (absorptive core) with thinner cellulose bres expressed higher lter paper absorbency, mainly due to the increasing length of the swollen cellulose bres in the cellulose pulp.e latter also implies uncomfortable feeling while wearing the incontinence diaper A 10, while samples I 9 and I 10+ boasted of by about 20% dryer surface of the PP-spunbond rst layer.From the conclusions drawn above, it is clear that apart from the incontinence diaper mass and thickness, which are very important in the absorbency of the diaper, the diameter of cellulose bres and the diameter of pores of the absorptive core, which represents about 64% of the mass of an incontinence diaper, are of the essence as well.inner cellulose bres in the pulp have larger speci c surface and ensure a larger number of cellulosebres in the pulp and a larger number of pores between the bres, which consequently leads to better absorbency.On the other hand, the thicker absorptive cellulose core increases in its volume in wet condition and the hydrophilic cellulose bres increase in length and a ect the rst PP-spunbond layer wetting and consequently cause an uncomfortable feeling while wearing an incontinence diaper.Moreover, the absorbency of analysed incontinence diapers depends on the quantity of the super absorber polymer (SAP) in the inner part of the diaper, which was not investigated in the presented research.
It is expected that the thicker sample (i.e.sample A 10) had a larger quantity of the super absorber polymer incorporated into its inner part (absorbent core).Besides the absorbency of the incontinence diaper, the dryness of the rst PP-spunbond layer is very important for the person using the incontinence diaper.From that point of view, samples I 9 and I 10+ that have by about 20% dryer rst PP-spunbond layer than sample A 10 are more suitable for use.With the research, the elastic recovery a er compression loading, water vapour transmission, absorbency, bending rigidity and pore size of incontinence diapers, which are designed for heavy (samples A 10 and I 10+) and regular (sample I 9) urinary and faecal incontinence, were analysed and compared.Furthermore, the absorbency of the analysed incontinence diapers depends on the quantity of the super absorber polymer (SAP) in the inner part of the diaper, which was not investigated in the presented research.

Figure 1 :
Figure 1: Incontinence diaper layers e mass and thickness of samples as well as the diameter of bres in the top sheet layer and cellulose pulp are listed in Table1.Table2includes the photos of a cross-sectional and upper view of samples analysed in the dry and wet condition a er the wetting with 200 mL of distilled water, recorded during the determination of elastic recovery a er the compression loading analysis.
point of the test in mm and h 2 the height of the relaxed sample (a er compression loading of 40 N and relaxation time of 1 min) in mm.Table 2: Upper and cross-sectional view of samples analysed in dry and wet condition (a er wetting with 200 mL of distilled water) with determination of elastic recovery a er compression loading analysis magni cation: le 30x, right 200x) SAP (magni cation 200x) Upper PP spunbond layer (magni cation 30x) PP spunbond layer (magni cation 400x) I 9 Inner Cellulose pulp (magni cation: le 30x, right 200x) SAP (magni cation 200x) Upper PP spunbond layer (magni cation: le 30x, right 200x) I 10+ Inner Cellulose pulp (magni cation: le 30x, right 400x) SAP (magni cation 200x) Upper PP spunbond layer (magni cation: le 30x, right 400x) on their Functionality Tekstilec, 2016, 59(4), 298-310 Bending rigidity Bending rigidity of incontinence diapers was determined according to ISO 9073-7 (Textiles -Test methods for nonwovens -Part 7: Determination of bending length) [20]

, where m 1
stands for mass of the dry sample [g] and m 2 for mass of the wet sample [g].

Table 4 :
Results of elastic recovery a er compression loading of dry samples

Table 5 :
Results of elastic recovery a er compression loading of wet samples

Table 6 :
Bending rigidity of samples

Table 7 :
Water vapour transmission of samples

Table 8 :
Filter paper absorbency on incontinence diaper surface (MDS method, part 3)

Table 9 :
Absorbency of incontinence diaper according to ISO 11948 (Rothwell method) and was the highest at sample A 10. e main reason for that lies in the smallest diameter of cellulose pulp bres, the highest mass and thickness, and consequently the highest number of pores at sample A 10. e absorbency of incontinence diapers depends • on the mass and thickness of the diaper and the quantity of the super absorber polymer (SAP) in the absorptive core.Sample A 10 with the highest absorbency (492.5%) also had the highest mass (1661.6 g/m 2 ) and thickness (10.48 mm), as well as the lowest diameter of cellulose bres in the cellulose pulp (29.4 µm) of the absorptive core.e above-mentioned facts are the reason for the highest number of pores (681 pores) at sample A 10 that increased the absorbency of the incontinence diaper.