Design and development of reusable cloth diapers

18 Pages·2013·1.52 MB·English

International Research Journal on Engineering Vol. 1(1), pp. 001-018, November, 2013
Available online at http://www.apexjournal.org
©2013 Apex Journal International

Full Length Research

Design and development of reusable cloth diapers

Hemdan Abdou Abou-Taleb

Textile Engineering Department, Faculty of Engineering, Mansoura University, 35516 Mansoura, Egypt.
Email: [email protected]

Accepted 31 October, 2013

Design and development of reusable cloth diaper are usually a response to an existing problem in the
disposable diapers. Disposable diapers are available at relatively expensive price and not easily
available for certain people or financially marginalized people, and yet there is need for these diapers.
This research was done to design and develop reusable cloth diaper for babies who have different
ages. 3-D weft knitted spacer fabrics were manufactured as a urine transport fabric i.e. (inner wick and
transfer layer) with three variables namely type of yarn combinations of both top and bottom layers,
type of spacer yarn (connecting yarn) and the patterning of spacer yarns with different angles. Also
terry woven clothes were manufactured as an absorbent fabric i.e. (absorbent and retained core) with
two variables namely pile height and picks/cm. And only one water repellant coated fabric was selected
for water repellency, prior to designing and evaluating the diaper. All the components used in the
development of this diaper were resistant to chlorine bleach and hot water during washing. When the
prototype was evaluated from user trials, it received approval when used with washing also.

Key words: Reusable, diaper, absorbent, fabric, babies

INTRODUCTION

A diaper is a kind of underwear that allows one to urinate (http://www.babycottonbottoms.com/how_many_
in a discreet manner. When diapers become soiled, they diapers.htm). An estimated 27.4 billion disposable
require changing ; this process is often performed by a diapers are used each year in the US, resulting in a
second person such as a parent or caregiver. Failure to possible 3.4 million tons of used diapers adding to
change a diaper on a regular enough basis can result in landfills each year
skin problems. (http://www.time.com/time/magazine/article/0,9171,17023
Diapers are made of cloth or disposable materials. 57,00.html
Cloth diapers are composed of layers of fabric such as Environmental pollution concerns affect to a great
cotton, bamboo or microfiber and can be washed and extent on the utilization of eco friendly product. The
reused multiple times. Disposable diapers contain Eureka Institute (http://www.
absorbent chemicals and are thrown away after use. The Planeteureka.org/marketplace/concepts/report) reported
decision to use cloth or disposable diapers is owing to that the smart eco diaper (nappy) in the United Kingdom
issues ranging from convenience, health, cost and their (UK) is a stylish solution to the billions of U.S. disposable
effect on the environment. Cloth diapers are reusable diapers that are thrown away each year. Another aspect
and can be made from natural fibres , man made to consider when choosing between disposable diapers
materials or a combination of both and cloth diapers is cost. It is estimated that an average
(http://www.ip.com/IPCOM/000209419) baby will use from $1500 to $ 2000 or more in disposable
Diaper consists of a waterproof outer layer sewn diapers before being potty- trained
together with absorbent material on the inside. There (http://blogs.consumerreports.org/baby/2009/07/ cloth-vs-
may also be an additional inner layer of moisture-wicking disposable-diapers-getting-started.html). Total cost for
material. All diapers have a velcro, snap or other closure reusable diapers would be $ 400 to $ 725, compared to $
to secure them on the baby. An average child will go 1600 to $ 2500 for disposables. The savings would be $
through several thousand diapers in his/her life 1200 to $ 2100 for three years, or $ 400 to $ 700 per year
002 Int. Res. J. Eng.

Figure 1. Components of a diaper.

(http://www.dailyfinance.com). Babies may have their diaper to be developed and functional requirements
diapers changes five or more times a day (Diapering needed to design and develop a quality product.
Your Baby). Children who wear diapers may experience
skin irritation, due to continual contact with fecal Katter ,
EXPERIMENTAL WORK
as faces contains urease which catalyzes the conversion

of the urea in urine to ammonia which can irritate the skin
Fabrication method of inner layer of reusable diaper
and can cause painful redness (Diaper Rash: The Bottom

Line). Samples preparation
The specific choice of a product depends on several
factors that include amount of urine loss, durability, ease Six weft- knitted spacer fabrics were used in this study.
of use , comfort , cost , pattern of urine loss and odour They were produced on the modern electronic V-bed flat
control ability (http://health.allrefer.com/health/urinary- knitting machine (STOLL 340.6 ST711 of Germany).
incontine-nce-products-info.html). Distance between both needle beds equals to 5 mm. The
machine gauge of 7 needles per inch was used.
In this study, polyacrylic 28/2 Nm yarn was used to knit
CREATIVE DESIGN FRAMEWORK single jersey for both top and bottom layers and three
structures (Structures I, II and III).
The major requirements involved in diapers were The structures shown in Figures 2 and 3 (I & II & III) are
absorbency and water retention within the middle layer used for comparison purposes in the study.
and comfort in terms of moisture levels and fabric feel on Table 1 presents the mass, thickness, bulk density,
the baby skin through the inner layer and water overall porosity and stitch density of all samples. The
repellency by the outer fabric layer as shown in Figure 1. specimens were knitted with the same yarn tension and
These critical factors were considered in designing the cam setting by using 180 needles. Before the
Abou-Taleb 003

Figure 2 Spacer yarn inclination
I- Shifting one needle distance ;
II- Shifting three needles distance;
III- Shifting five needles distance

Figure 3. Spacer fabric construction

Table1. 3–D Weft knitted spacer fabric specifications.

Sample Mass Thickness Bulk density Overall porosity Stitch density
No. (g/m2) at 0.5 g/cm2 (mm) (g/cm3) (%) (stitch /inch2)
1 817 5.015 0.1629 86.08 105.14
2 667 5.565 0.1199 89.75 175.45
3 433 4.435 0.0976 91.66 198.05
4 717 4.593 0.1561 86.66 114.83
5 617 4.939 0.1249 89.32 120.44
6 `516 5.945 0.0868 92.58 189.76

measurements and tests, the samples were conditioned Water vapour permeability
in standard atmospheric conditions (20 ± 2°C, RH 65 ±
5%) for two days . All tests were carried out in standard Water vapour permeability (WVP) was measured using
atmosphere. the cup test method according to BS 7209 (British
Standard, 1990), where four samples were measured
and the mean value was recorded . The weight loss was
Measurement of water transport properties
converted to water vapour permeability according to

Equations (1 & 2)
Air permeability

M
Air permeability was measured according to BS. 5636 WVP = , (g/m 2.hr) (1)
A.t
(British Standard , 1990) In this test, ten samples were
tested and the mean value was reported for each sample. ∏ d2
A = ×10 −6 , m 2 (2)
The reciprocal of air permeability value is called air 4
resistance.
004 Int. Res. J. Eng.

Figure 4. Vertical wicking apparatus

Where: M is loss in mass (g), t is time between weighing The average of 10 results was considered
(hours), A is internal diameter of dish (mm) , and WVP
is the water vapour permeability of the test fabric
Horizontal (transfer) wicking test

Vertical wicking test Transfer wicking properties were measured according to
the stated method (Zhuang et al., 2002). Samples were
Vertical strip wicking tests were performed on the mounted horizontally to conduct transfer wicking
apparatus shown in Figure 4. Five specimens of 200 mm experiments. When the samples were set horizontally,
× 2.5 mm cut along the walewise and coursewise 130 mm diameter dish was placed on top of the layers,
directions were prepared. The specimen was suspended and the external pressure was exerted by changing
vertically with its bottom end dipped in a reservoir of amounts of sand in the dish. In this study, the external
coloured distilled water at 21°C. In order to ensure that pressure was 126 kg/m2. Fabric samples were cut into
the bottom ends of the specimens could be immersed 130 mm diameter circles, which were the same size as
vertically at a depth of 30 mm into the water, the bottom the dish placed on the fabrics. The specimens were
end of each specimen was clamped with 1.2g clip, as completely soaked in distilled water for 24 hours. They
shown in Figure 4. The wicking heights, measured for 24 were suspended in free air for about 30 minutes to drip
hours , were recorded along the walewise and courswise out the excess water absorbed by the samples. Another
directions for a direct evaluation of the fabric wicking sample of the same fabric with the same diameter was
ability cut and dried for one hour in oven at 100°C and the dry
weight (m ) was measured. The dry specimens were put
d
on the wet specimens for 30 minutes under 12.6 g/cm2
Static water absorption test pressure and the weight (m ) was measured. The
w
amount of water transmitted was calculated by the
The fabric samples were cut into equal size of 100 mm × following equation :
100 mm and conditioning in the standard atmospheric
condition of 65 ± 2% RH and 20 ± 2°C. The fabrics were Amount of water transmitted = m – m , g/m2/30
w d
conditioned for 24 hours in the above – mentioned minutes (4)
atmospheric conditions and the dry weight (m ) was
d
measured. To study the water absorbency, samples were
dipped in distilled water for 24 hours to ensure uniform Drop spreading test
soaking of water and then wet samples were hung in free
air for about 30 minutes to drip out the excess water The spreading study (Shamal, 2009) was performed by
absorbed by the samples. Now , the weight (m ) of wet dropping a small ink drop (3 ml) by a burette from a
w
samples was measured. The experiment is repeated for distance of 2 cm above the surface of the fabric samples.
three specimens and the mean value is taken and It was observed that the ink immediately penetrates
recorded. The water absorbency (Debnath and inside the fabric. It was observed that the ink immediately
Madhusoothanon, 2010) was calculated using the penetrates inside the fabric through the inter-yarn spaces
following formula : and then starts spreading in the outwards direction from
the place where the drop was placed. After the spreading
Water absorbency (%) = (m – m ) / m × 100 ……(3) was over and ink was fully dried, the inner fabrics
w d d
Abou-Taleb 005

ا

Figure 5. Spreading of drop on polyacrylic weft knitted spacer fabrics

Table 2. Range of variation for studies factors.

Levels
Factors Interval
-1 0 +1
X - Type of yarn
1 one yarn of polyacrylic two yarns of polyacrylic three yarns of polyacrylic
combinations of both top one yarn
28/2 Nm fed only 28/2 Nm fed together 28/2 Nm fed together
and bottom layers

X - Type of spacer yarn one yarn of polyacrylic two yarns of polyacrylic Three yarns of polyacrylic
2 one yarn
(connecting yarn) 28/2 Nm fed only 28/2 Nm fed together 28/2 Nm fed together

Structure (I) Structures (II) Structures (III) shifting two
X - The patterning of
3 needles
spacer yarns with different shifting one shifting three shifting five
distance
angles needle distance(11°) needles distance (31°) needles distance (44.5°)

.
surfaces were scanned by canon scan LIDE 80 at 600 The experiments carried out on three-dimensionally
resolution ratio and images were used to calculate static weft knitted spacer fabrics were planned according to the
maximum spreading area (cm2). Three specimens were simplex lattice method for the three variables i.e. type of
tested. Typical drop spreading images of different fabrics yarn combinations of both top and bottom layers (X ) ,
1
are shown in Figure 5. type of spacer yarn (connecting yarn) (X ) , and the
2
The fabric's thickness and surface density was patterning of spacer yarns with different angles (X ).
3
measured in accordance with ISO 5084: 1996 and LST The variation of these factors is given in Table 2. The
ISO 3801 : 1998 , respectively. The details of these tests design of simplex lattice method for three components is
are listed in Table 1. given in Table 3. The mixture levels of simplex lattice
method are converted to factorial design levels as listed
in Table 3. The second – degree polynomial of mixture
MIXTURE DESIGN design in three components has the general form:

The simple lattice method for the experiments was
Yˆ = ∑ BiXi + ∑ Bij XiXj ( 5 )
chosen because of its obvious advantages of analysis of
all the quadratic and interaction effects (Akhnagarova
and Kafarov, 1978). Where :
006 Int. Res. J. Eng.

Figure 6. The cross-section of a towel through the warp.

Table 3. Experimental design of studies factors.

Coded level of factors
Sample
Simplex lattice method Factorial design method
No.
x x x X X X
1 2 3 1 2 3
1 1 0 0 +1 -1 -1
2 0 1 0 -1 +1 -1
3 0 0 1 -1 -1 +1
4 0.5 0.5 0 0 0 -1
5 0.5 0 0.5 0 -1 0
6 0 0.5 0.5 -1 0 0

Table 4. Yarn types used in the production of terry fabrics.

Pile warp yarn Ground warp yarn Weft yarn
24/2Ne twisted ring spun carded 24/2Ne twisted ring spun carded 16/1Ne ring spun carded cotton
cotton yarn, (308 turns /meter) cotton yarn, (308 turns /meter) yarn,
(614 turns /meter)

ˆ structures discussed in this study. Three types of yarns
Y= The measure response for each experiment ,
were used in the production of terry fabrics, namely weft
bi = Coefficient of the main factor effects ,
yarn , ground warp yarn and pile warp yarn. The
bij = Coefficient of the interaction effects , and
construction of terry fabrics is presented in Tables 4 and
q = Number of the chosen factors.
5. Table 4 shows the properties of weft, ground warp and

pile warp yarns. Three different pile heights and three
In order to determine the regression coefficients, the
different weft densities (defined as pile density) were
response (Yˆ)has to be found by using different
used to produce the different terry fabric constructions,
experimental combinations of the variables under the
these are shown in Table 5.
consideration.
The pile of the terry fabrics used in the research was
The mathematical models obtained by simplex lattice
constructed on both sides of the fabric. As can be seen in
method could be modified by converting the coded levels
Figures 6 and 7, the ground warp (G ) that was up at the
of factors (0, 0.5, 1) to correspond with the factorial 1
beginning went down and the (G ), which was down,
design levels (-1 , 0 , +1 ) as listed in Table 3. 2
went upward through the two yarns. Back side pile (BP)

warp was always in opposition to the front side pile (FP)

warp. When the (BP) warp made the first loop on one
Fabrication method of middle layer of reusable diaper
side of the fabric, the second loop was formed on the

other side. The (FP) warp behaved in the same manner.
Samples preparation

The terry fabrics used in the middle layer were woven Production method of the terry fabrics
using cotton yarns. The both sided pile formation

principle was used in the production of the terry woven The terry fabrics were produced on a 300 cm Nouva
Abou-Taleb 007

Table 5. Warp density, weft density and pile type (height, density) of terry fabrics.

Pile warp density Ground warp Weft density Pile height for Pile density
(ends/cm) density (picks/cm) each side (No. of piles/cm2)
(ends/cm) (mm)
12 12 9, 15 , 21 4 , 5 , 6 18 , 30 , 42

Figure 7. The weave repeat of the terry fabric (Basic 3-pick terry weave in 1:1
warp order).

Pignone TPS 500 model rapier terry weaving machine
with a doppy using the three-pick principle. With the S = (m −m )/m ×100 , %.........................( 6)
w w d d
combination of three different pile heights and three
different weft densities (defined as pile densities), nine
different terry fabric constructions were produced for the Surface water absorption test
experiments. Piles are formed on both sides by the
variable periodic movement of the reed or cloth fell Surface water absorption of terry fabrics was measured
position, mostly over three picks. according to the stated method (ASTM D4772-09). This
method determines the ability of a terry fabric to rapidly
absorb and retain liquid water from surfaces such as
Measurement of water absorption and retention human skin. Specimens are placed in a embroidery hoop
properties 15.3 cm (6 inch) outer diameter of inner hoop and then
the hoop/specimen assembly is placed at an angle (60°)
Surface density test to the table top (Figure 8).
The 200-ml of distilled water weighed (m ) graduate
o
The fabric's thickness and surface density was measured mounted on the apparatus was parallel to the table top.
in accordance with ISO 5084 : 1996 and LST ISO 3801 : The pour spout on this graduate was 3 cm down from
1998 , respectively . where the adjustment screw bracket joints the outer hoop
and 0.6 cm away from the hoop/specimen assembly.
After water flows down the surface of each specimen, the
Static water absorption test amount of water retained by each specimen is measured
(∆W) as follows:
The static water absorption was measured according to
method (Karahan and Eren, 2006). The samples were
conditioned in laboratory conditions, cut into pieces (10 ∆W = m – m , grams ……………. (7)
o 1
cm × 10 cm) and then weighed (md). After that the
samples were kept for one minute in distilled water. After Where
being removed from the water , they were hung for three ∆W = surface water absorption , grams
minutes to remove excess water , and the weight of the m = the weight of water in the funnel , grams
o
wet samples (mw) was measured. An electronic balance m1 = the weight of collected water in the pan (dish) ,
was used in the weight measurements. The static water grams
absorption (Sw) was calculated before and after
laundering using the following formula : Six specimens are tested , three on the face of the fabric
008 Int. Res. J. Eng.

Figure 8. Schematic diagram of a typical water flow tester.

Table 6. Experimental plan.

Coded form
Factors
-1 0 +1
X = pile height , mm 4 5 6
1
X = Picks per cm 9 15 21
2

and three on the back of the fabric. In this test four samples each one (1 inch × 1 inch) are
The six observations are averaged to determine the tested at a time. The details of these tests are listed in
surface water absorption of the fabric . Table 10.

Liquid retention test Design of experiment

The liquid retention capacity was determined according to In the present study two independent factors and three
the method in Ref. (Petrulyte and Nasleniene, 2010), the levels of each factor were chosen to conduct the
samples were conditioned in laboratory conditions, cut experiments. The parameters selected as independent
into pieces (1 inch × 1 inch) and then weighed (m ). This factors were: (i) pile height , mm (X ) and (ii) picks per cm
o 1
test involves measuring the amount of liquid retained by (X ). The details of experimental plan are given in Table
2
the sample after a drainage process. For the wetting 6.
procedure the specimens were placed in distilled water The dependent variables studied were surface density,
for 2-3 sec, which is necessary to complete wetting, and static water absorption before and after laundering,
dried in air for 90 min and then the specimen is weighed surface water absorption and water retention of terry
(m ). The amount of liquid retained by dry weight of the woven fabrics.
1
sample is a measure of the capacity of the sample as An orthogonal mathematical plan was to investigate
follows: water absorption and retention properties of terry fabrics.
The matrix of the mathematical plan is presented in Table
Water retention = (m – m )/m × , % (8) 7 .
1 o o
Abou-Taleb 009

Table 7. Matrix of the mathematical plan.

X (Pile height , mm) X (Picks per cm)
1 2
No.
value of matrix real value value of matrix real value
1 -1 4 -1 9
2 +1 6 -1 9
3 -1 4 +1 21
4 +1 6 +1 21
5 -1 4 0 15
6 +1 6 0 15
7 0 5 -1 9
8 0 5 +1 21
9 0 5 0 15

Table 8. Measurement of water transport properties of 3-D weft knitted spacer fabrics.

Air Water vapour Vertical wicking height Water Amount of water
Wetting area
Exp. resistance permeability (mm) absorbency transmitted
No. (pa.sec)/m ((g/m2/hr) Wale Course (%) (g/m2/30 min) (Cm2)
Y Y Y Y Y Y Y
1 2 3 4 5 6 7
1 301.73 1056.3 9.5 13 296.3 184.5 3.8465
2 266.67 1207.2 10 7.83 441.2 449.9 6.3854
3 87.19 2148.1 8 9.33 544.0 344.1 4.7298
4 153.12 1148.4 11.75 13 345.4 212.2 5.3131
5 96.83 3918.9 13.5 11.33 449.1 322.7 4.5220
6 94.96 4607.1 7 8 420.0 437.0 3.8524

Table 9. Response – surface equations of water transport properties of 3-D weft knitted spacer fabrics.

Response – surface Equation R
Y = 17.11-77.84 X1 – 79.72 X2-136.0 X3 – 97.63 X1X3 -81.97 X2X3-131.08 X X 1
1 1 2
Y = 7468.5 + 2861.5 X + 3549.6 X + 6320.1 X +16.6 X X + 2316.7X X + 2929.4 X X 1
2 1 2 3 1 2 1 3 2 3
Y = 18.5 +11.5 X + 5 X + 6.75 X + 2X X + 4.75X X –2X X 1
3 1 2 3 1 2 1 3 2 3
Y = 15.3113 +7.3113 X + 3.9813 X + 4.25 X +0.6463 X X +0.165 5X X – 0.58 X X 1
4 1 2 3 1 2 1 3 2 3
Y = 573.8 +153.8 X + 124.6 X + 228.4 X - 23.4 X X + 29 X X – 72.6 X X 1
5 1 2 3 1 2 1 3 2 3
Y = 482.626 +45.653 X + 159.923 X + 270.421 X – 105.025X X + 58.413 X X –39.983 X X 1
6 1 2 3 1 2 1 3 2 3
Y = 4.283 + 0.431 X – 0.239 X + 0.894 X – 1.726 X X + 0.234 X X – 1.705 X X 1
7 1 2 3 1 2 1 3 2 3

Fabrication method of outer layer of reusable diaper measured five times at 20 ± 2°C and RH 65 ± 2% and the
average waterproofness results was obtained
Fabric selection The coated laminated polyester fabrics were tested for
water penetration and colour retention when exposed to a
Outer layer of reusable diaper consists of a thin layer of chlorine bleaching solution using 5% of chlorine
polythene plastic sheet (30 g/m2) sandwiched between concentration.
two sheets of densely coated waterproof polyester woven
fabric.

RESULTS AND DISCUSSION

Measurement of water repellency of lamena
Water wicking and transport properties of 3-d weft
Waterproofness was tested according to BS EN 20811 knitted spacer fabrics
using hydrostatic head tester with 10cm/min applied
pressure speed. Samples with 60mm diameter were Table 8 shows the experimental values of air resistance,
010 Int. Res. J. Eng.

Figure 9. Air resistance contours of 3–D weft knitted spacer fabrics .

Figure 10. Water vapour permeability contours of 3-D weft knitted spacer fabrics .

water vapour permeability , vertical wicking height in and transport material using standard statistical software.
walewise and coursewise directions , water absorbency , Effects of type of yarn combinations, type of spacer
amount of water transmitted and wetting area of 3-D weft yarn and the patterning of spacer fabrics on water
knitted spacer fabrics using factorial design, Table 9 transport properties were studied. Figures 9-15 show the
shows the coefficients and constants of the response effect of the three studied factors on water transport
surface equations. properties. It is observed that all the water transport
The value of correlation coefficient (R) shows good and properties. It is observed that all the water transport
significant relationship between the predicted and properties increase with decreasing both type of yarn
experimental values. The contour diagrams (Figures 9 – combination and type of spacer yarn and then with further
15) were drawn to understand the individual and increase of patterning of spacer fabrics water transport
interaction effects of water vapour permeability, vertical properties increase. This means that sample No. (3) is
wicking height walewise and coursewise directions, water the best selected one with respect to water transport
absorbency, amount of water transmitted and wetting properties . Probably, with decrease in type of yarn
area of 3-D weft knitted spacer fabrics as a wicking combination and type of spacer yarn less entanglement