TECHNICAL FIELD
[0001] The present subject matter relates to determination of in-use properties of a cleansing soap and, in particular but not exclusively, to apparatus and methods for determining wear rate of a soap bar.
5 BACKGROUND
[0002] Soap bars are generally tested for various properties, such as lather, rinse-ability, mildness, wear rate, etc., to determine suitability for consumer use. The wear rate refers to the rate at which a soap bar wears down during use and indicates the economy of the soap bar. Low rate of wear is generally one of the
10 desirable characteristics that consumers seek. Hence every new soap bar
formulation is generally tested for wear rate.
[0003] Typically, wear rate is determined by a manual method whereby a person manually hydrates the soap in regular intervals. In manual process the pressure applied in each cycle of hydrating the soap bar may differ and hence may result
15 into inaccurate results. Moreover, these methods are labor intensive, time
intensive, person dependent, and prone to errors. The result may change every time the test is conducted as it is not possible to precisely subject the sample bar to the same washing treatment conditions every time manually.
20 SUMMARY
[0004] This summary is provided to introduce concepts related to apparatus and
methods for determining the wear of a cleansing bar, such as opaque bar,
translucent bar, transparent bar and such other soap bar. This summary is not
intended to identify essential features of the claimed subject matter nor is it
25 intended for use in determining or limiting the scope of the claimed subject
matter.

[0005] In one implementation, an apparatus for determining wear of soap
includes a sample holder which hold the sample soap, an abrader holder to hold an
abrader, a control motor which controls the motion of the sample holder and/or
abrader, and a sprayer with a nozzle and fluid inlet at different ends to spray water
5 on the sample soap bar. The abrader may have an abrasive surface and may be
detachably held in the abrader holder to allow use of different abraders for different tests.
[0006] Water from the nozzle is poured on the soap bar for a specific time while
the soap is exposed to the abrasive surface, and this process is repeated several
10 times at various intervals. The soap is then dried and the weight of the soap bar is
measured before and after the test. In one example, the weight may be measured using weight sensors present in the apparatus.
BRIEF DESCRIPTION
15 [0007] The detailed description is described with reference to the accompanying
figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or method in accordance with embodiments of the
20 present subject matter are now described, by way of example only, and with
reference to the accompanying figures, in which:
[0008] Figure 1 illustrates a block diagram of an apparatus for measuring the wear of soap bar, in accordance with an embodiment of the present subject matter [0009] Figure 2a schematically illustrates a front view of an apparatus for
25 measuring the wear of soap bar, in accordance with an embodiment of the present
subject matter.
[0010] Figure 2b schematically illustrates a top view of an apparatus for measuring the wear of soap bar, in accordance with an embodiment of the present subject matter.

[0011] Figure 2c schematically illustrates an isometric view of an apparatus for measuring the wear of soap bar, in accordance with an embodiment of the present subject matter.
5 DETAIL DESCRIPTION
[0012] The present subject matter relates to apparatus and method for determining the wear rate of soap bars. Soap bars are widely used by consumers for varied purposes such as washing clothes, utensils, bathing and the like, on a regular basis. Hence it is desirable for soap bars to be economic, i.e., last longer, to give
10 more value for the money spent by the consumers in purchasing the soap bars. The economy of soap bars is determined by various characteristics such as mush, wear rate, and the like. Wear rate of a soap bar refers to the rate at which the soap bar loses weight during use and is thus crucial for the soap to be economic. The wear rate of soap bars is influenced by the shape and hardness of the bar. Since
15 different soap formulations and production methods may result in different shapes and hardness of bars, the soap bars made from different soap formulations need to be tested for wear rate to determine suitability for production. [0013] Conventional method of calculating the wear rate of soap bars is manual. The manual method typically involves measuring the initial weight of the soap
20 bar, thereafter washing the soap bar for a specific time in tap water, which is repeated at an interval of 30 minutes over a period of 6 hours. The bars are then allowed to dry for 24 hours at room temperature in dry soap dishes and then the final weight of the bar is recorded. Depending upon these results the wear rate is calculated as the % loss in weight by the mathematical equation 1.
25 Wear rate = ^TZvZ?^) * 100 1
[0014] The known manual methods of determining the wear rate are labor dependent, and hence results are not accurate or repeatable, and moreover time taken is more. The test results in manual methods entirely depend upon the person conducting the test, and hence the results vary as it is not possible to precisely
30 subject the sample bar to the same washing conditions every time. Also, the

manual handling of soap during the washing cycle introduces many subjective variables.
[0015] Various embodiments and implementations of the present subject matter
describe apparatus and methods for determining the wear rate of soap bars, such
5 as but not limited to opaque soap, washing soap, bathing soaps, transparent soaps
and the like. In an example, the system includes an apparatus that holds the soap bar sample and hydrates the soap bar using water sprayed from a nozzle of a sprayer, and an abrader holder holding an abrader having an abrasive surface. Relative motion can be provided between the abrader and the soap bar sample to
10 wear the soap in different direction and patterns. The soap bar can be weighed
before and after the test to determine the wear rate using the formula provided above. The test can also be repeated multiple times for validation.
[0016] The present invention thus obviates the need of manually washing the soaps and it ensures uniform treatment to all samples during every washing cycle
15 and hence substantially reducing margin of errors accruing from variable handling
of soap bars during different washing cycles. Thus, the present invention enhances uniformity, repeatability, and accuracy of the wear rate test carried out under different pre-defined settings. [0017] The above apparatus and methods are further described in conjunction
20 with the following figures. It should be noted that the description and figures
merely illustrate the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its scope.
25 [0018] Furthermore, all examples recited herein are principally intended expressly
to be for the purpose of assisting the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein
30 reciting principles, aspects, and embodiments of the present subject matter, as
well as specific examples thereof, are intended to encompass equivalents thereof.

[0019] The manner in which the apparatus and methods of the present subject
matter may be implemented has been explained in details with respect to the
appended figures. While aspects of described system(s) and method(s) of the
present subject matter can be implemented in any number of different
5 environments, and/or configurations, the embodiments are described in the
context of the following system(s).
[0020] Figure 1 illustrates the block diagram of an apparatus 100 for determining the wear rate of soap bars, in accordance with an embodiment of the present subject matter. The block diagram includes various example elements that may be
10 present in the apparatus 100 in one implementation. However, it will be
understood that in different implementations, certain additional elements may also be present and in other implementations, some of the optional elements may not be present. [0021] In one implementation, the apparatus 100 includes a sample holder 102, to
15 hold the sample soap bar to be tested. The sample holder 102 may be
implemented in different forms as will be understood. For example, the sample holder 102 may be a holding clamp, or a screw fitted holder, or the like. [0022] The apparatus 100 further includes an abrader holder 104, to hold an abrader 118 having an abrasive surface. The abrader 118 may be used for wearing
20 down the sample soap bar during test to simulate in use conditions. For example,
the abrader 118 may be a brush, scrubbing pad, loofah, fluffy sponge, sponge, cloth, polymer based sheet/ block, stones/black siporex and the like. In one implementation, the abrader 118 may be detachably attached to the abrader holder 104. Hence, like the sample holder 102, the abrader holder 104 may also be
25 implemented in different forms, such as clamp holder, screw fitted holder, etc. In
another implementation, the abrader 118 may be fixed to the abrader holder 104. [0023] The distance between the sample holder 102 and abrader holder 104 may be adjustable. For this, in one implementation, at least one of the sample holder 102 and abrader holder 104 may be disposed over rails or may be attached to a
30 telescopic rod or may be made movable by other means known in the art. Further,
at least one of the sample holder 102 and abrader holder 104 may be associated

with one or more control motors 106 to control its motion in different directions.
In one implementation, the apparatus 100 includes a plurality of abrader holders
104 and a plurality of control motors 106, wherein each control motor 106 is
adapted to control the motion of a respective abrader holder 104. The control
5 motor 106 may be a DC motor, a stepper motor, induction motor and the like.
[0024] The apparatus 100 also includes a sprayer 108 having a nozzle 110 and a fluid inlet 112. The nozzle 110 may be a cylindrical or round or other shaped spout at one end of the sprayer 108 and can be used to direct a jet of water on to the sample soap bar during the test. The sprayer 108 may be disposed so that it
10 does not interfere with the movement of the sample holder 102 or the abrader
holder 104. For example, the sprayer 108 may be disposed between two abrader holder(s) (104). Further, the sprayer 108 may be positioned to direct water on an area where the abrader 118 would contact the sample soap bar during operation of the apparatus 100. Further, the position of the sprayer 108 may be varied by a user
15 depending on the test to be performed. Accordingly, the sprayer 108 may be
mounted on fittings that may be detachable or movable as would be understood by a person skilled in the art.
[0025] In one implementation, the sprayer 108 comprises a plurality of nozzles 110. In another implementation, the apparatus 100 includes a plurality of sprayers
20 108. In one example, the plurality of sprayers 108 may be arranged equidistant
from each other in a circumference around the sample holder 102. In another example, the plurality of sprayers 108 may be arranged in any other pattern to simulate in use conditions. [0026] The sprayer 108 can further include a valve 114 connected at the fluid
25 inlet 112 of the sprayer 108 to control a spray velocity and pattern of the fluid. In
one example, a spray controller 116, such as a microprocessor or other programmable device, can be connected to the valve 114 to control the flow of water through the nozzle 110 released on the sample soap bar. In another example, the valve 114 may be manually controlled and the spray controller 116
30 may be a knob.

[0027] The apparatus 100 can further include a platform 120 on which the
sample holder 102 and the abrader holder 104 can be mounted. For example, the
platform 120 may include a tray and mounting elements, such as rods or rails or
holders or other fixtures, fastened to the tray. The sample holder 102, the abrader
5 holder 104, the sprayer 108, and other components may be connected to the
mounting elements for mounting on the platform 120. Further, a drain 122 may be present in the apparatus 100, for example, in the tray of the platform 120, to drain away the water used during the test. The drain 122 may be a channel, pipe, trench, pit or pipe for the water to flow. The drain 122 may be on one corner of the
10 platform 120.
[0028] In one implementation, a load sensor 124 may be present on the sample holder 102, to measure the weight of the sample soap bar before and after the test. In another implementation, the load sensor 124 may be separately mounted on the platform 120. In yet another implementation, the weight of the sample soap bar
15 may be measured external to the apparatus 100, for example using a weighing
scale. In one implementation, a dryer 126, is also mounted on the platform 120 to blow air to dry the soap after it has been hydrated.
[0029] In operation, during hydration of the soap bar, the sample holder 102 holds the soap bar, the abrader holder 104 holds the abrader 118 such that the abrasive
20 surface of the abrader 118 brushes against a surface of the sample soap bar, and
water is sprayed from the sprayer 108 on the sample soap bar. The abrasive surface of the abrader 118 may brush against the soap surface in different patterns that may be controlled using the control motor 106, which controls the relative motion of the sample holder 102 and abrader holder 104. For example, the control
25 motor 106 may cause the sample holder 102 to spin or move in a vertical or
horizontal direction or a combination thereof. In another example, the control motor 106 may cause the abrader holder 104 to move in a vertical or horizontal or radial direction or a combination thereof. The weight of the sample soap bar is measured, for example, using the load sensors 124 affixed onto the sample holder
30 102.

[0030] The above discussed process of hydration can be carried out at various
time intervals over a pre-defined duration. The sample soap bar is then dried, for
example, using dryers 126 present in the apparatus 200, followed by measurement
of the weight of the dried sample soap bar. Depending upon the initial and final
5 weight of the sample soap bar, the wear rate is calculated using the previously
mentioned mathematical equation 1.
[0031] In one implementation, a control system 128, such as a computing device, a microprocessor, or the like, may be used to automate the operation of the apparatus 100. For example, the control system 128 receives input parameters
10 from a user to control the various components of the apparatus 100, such as the
valve 114, the control motor 106, etc., and output readings from the test performed. The input parameters can include, for example, a time of test and intervals of hydration, direction and speed of relative motion between the sample holder 102 and the abrader holder 104, and a pattern of the fluid sprayer 108. The
15 readings can include weight of the sample soap bar before and after the test and at
user specified intervals.
[0032] In operation, a method of determining wear rate using the apparatus 100 starts with receiving user inputs comprising a time of test, a direction and speed of relative motion between the sample holder 102 and the abrader holder 104, and a
20 pattern of the fluid spray. For example, the control system 128 may receive the
inputs. In other example, there may be separate controllers for each of the components and the inputs may be provided separately by the user to each controller. The sample soap bar is placed in the sample holder 102 and an initial weight of the sample soap bar is received. For example, load sensors placed in the
25 sample holder 102 may provide the initial weight. In other examples, the weight
sensors may be placed at a different location on the apparatus 100 or the weight may be taken separately outside the apparatus 100. The test is then performed on the sample soap bar according to the user inputs, i.e., water of desired hardness level is sprayed onto the soap bar as per the user-defined spray pattern for the
30 user-defined time, and the sample holder 102 or the abrader holder 104 are moved
relative to each other. The soap bar is then dried, for example, using a dryer. A

final weight of the sample soap bar after the test is received. The final weight can
be taken in a manner similar to the initial weight. The wear rate can be thus
determined as the percentage loss of weight of the soap using equation 1 above.
[0033] Example implementation of the apparatus 100 are further described with
5 respect to a specific implementation shown in Figures 2a-2c. However, it will be
understood that other implementations that incorporate the teachings of the present disclosure are also possible and are included within the scope of the appended claims. [0034] Figure 2a illustrates the front view of the apparatus 100 used for
10 determining the wear rate of the sample soap bars, in accordance with an
embodiment of the present subject matter. In one embodiment, the apparatus 100 includes a sample holder 102 used for holding the soap bar sample, whose wear rate is to be determined. The sample holder 102 may have different movement patterns and it may move in different axis or may be stationary. The sample
15 holder 102 may be attached to the apparatus 100 fixedly or may be detachable.
[0035] In one implementation, the sample holder 102 may be stationary such that the abrasive surface of an abrader held in the abrader holder 104 comes in contact with the soap bar from at least one direction at a predetermined frequency. In another embodiment, the sample holder 102 may move along its vertical axis in its
20 operative configuration, or it may move along horizontal axis. In one
embodiment, the sample holder 102 may be a screw fitted holder, or a clamp holding the soap bar and the like. In yet another example the sample holder 102 may move in circular movement and may spin partially or completely, depending upon the control motor.
25 [0036] In accordance with an embodiment of the present subject matter, the
apparatus 100 includes an abrader holder 104, which holds the abrader 118, where the abrader 118 has an abrasive surface which comes in contact with the sample soap bar. In one example the abrader holder 104 may be stationary and the sample holder 102 may move along it such that, the abrasive surface comes in contact
30 with the soap bar at a predetermined frequency. In another example the abrader
holder 104 may move concentrically inwards and outwards around the sample

holder 102 with the sample holder 102 in between. In yet another example the abrader holder 104 may move in diametrically opposite manner from different directions to come in contact with the sample soap bar.
[0037] In addition, the abrader 118 may be a brush, scrubbing pad, loofah fluffy
5 sponge, sponge, cloth, polymer based sheet/ block, stones/black siporex and the
like. The abrasive surface may be bristles etc. which comes in contact with the soap bar sample.
[0038] Further the apparatus 100 includes a control motor 106 which controls the motion of the sample holder 102 and/or abrader holder 104. In one example the
10 control motor 106 may control the motion of the sample holder 102 while the
abrader holder 104 being stationary. In another example the control motor 106 may control the motion of the abrader holder 104 while the sample holder 102 being stationary. [0039] In accordance with an embodiment of the present subject matter, the
15 apparatus 100 includes a sprayer 108 wherein the sprayer 108 comprises a fluid
inlet 112 at one end to receive a fluid and at least one nozzle 110 at another end to spray the fluid on the sample soap bar. The sprayer 108 may be arranged in circular manner around the sample holder 102. In one embodiment, at least two sprayers 108 may be arranged in a diametrically opposite manner at uniform
20 distance from the sample holder 102.
[0040] In one embodiment, the fluid inlet 112 is at one end of the sprayer 108 from where the fluid is introduced into the apparatus 100 for hydrating the soap bar sample. A platform 120 on which the sample holder 102, the abrader holder 104, the control motor 106, and the sprayer 108 are mounted, wherein the
25 platform 120 includes a drain 122 to drain away the fluid.
[0041] As seen in figure 2a, the platform 120, for example, may have a rectangular shape or it may be a square, a hexagon, an octagon etc. The platform 120 includes the tray and other mounting elements. Further the platform 120 may be made of metal or plastic or the like. The sample holder 102, as seen in figure
30 2a, is mounted on the tray of the platform 120 with the help of mounting
elements, for example, two vertical bars and a horizontal bar disposed on top of

the vertical bars. The holding clamp is attached to the center of the horizontal bar
with the axis of the holding clamp being vertical to hold the soap in a vertical
direction. It will be understood that other configurations of mounting elements are
also possible. For example, the holding clamp may be disposed at one end of the
5 platform 120 to hold the soap in a horizontal orientation rather than a vertical
orientation.
[0042] Also, as seen in the example implementation of figure 2a, the control motor 106 is mounted on top of the horizontal bar of the sample holder 102, just above the holding clamp. Accordingly, the control motor 106 can control spinning
10 and/or vertical motion of the sample holder 102. Further the figure 2a shows that
the abrader holder 104 may be L shaped so that the base of the abrader holder 104 can be attached (fixedly or detachably) to the tray of the platform 120. In another example, the abrader holder 104 may be mounted on the platform 120 using an L shaped bracket. As seen further, the abrader holder 104, holds an abrader 118
15 which is a brush in one example, and is placed such that the bristles of the brush
come in contact with the sample soap bar. In other examples mentioned earlier, the abrader 118 may be selected from scrubbing pad, loofah fluffy sponge, sponge, cloth, polymer based sheet/ block, stones/black siporex and the like. [0043] Figure 2b illustrates the top view of the apparatus 100 used for
20 determining the wear rate of the sample soap bars, in accordance with an
embodiment of the present subject matter. In one embodiment, the apparatus 100 includes a nozzle 110 which is at another end of the sprayer 108 from where the fluid water is thrown on the soap bar sample. In one example the flow of the water from the nozzle 110 may be in the form of unidirectional jets or the nozzles 110
25 may be adapted to release water in varying patterns to simulate real-life usage of
soap bars during their actual use. In yet another embodiment the direction of water flow from the nozzle 110 may be perpendicular to the direction of the movement of the soap holder. [0044] In another embodiment, the pressure of water released through the nozzle
30 110 may be changed and monitored. In yet another embodiment the temperature
of the water introduced in the nozzles 110 can be controlled and monitored.

Further the mineral content of water and/or its hardness can be measured during testing.
[0045] As seen in figure 2b the top view of the apparatus 100 shows four
abrader(s) 118, as brushes which are placed equidistant to each other around the
5 sample holder 102. Here the abrasive surface is bristles of the brush, but it may be
surface of different materials like a sponge etc. Also seen are two sprayer(s) 108 which are placed in between two brushes to hydrate the sample soap bar. The nozzle 110 is disposed at one end of each sprayer 108 and can be used for spraying water while the wear rate test is being carried out.
10 [0046] Figure 2c illustrates the isometric view of an example embodiment of the
apparatus 100 used for determining the wear rate of the sample soap bars, in accordance with an embodiment of the present subject matter. As seen in the figure 2c, the sprayer 108 is connected to the tray on platform 120 by a base, which is a mounting bracket. In one example, an assembly of two pipes connected
15 to each other forms the sprayer 108. The open end of the horizontal pipe denotes
the fluid inlet 112, which is used as a liquid input to the apparatus 100, whereas the open end of the vertical pipe is where the nozzle 112 can be attached.
EXAMPLE
[0047] The disclosure will now be illustrated with working examples, which are
20 intended to illustrate the working of disclosure and not intended to be taken
restrictively to imply any limitations on the scope of the present disclosure.
Although methods and apparatuses similar or equivalent to those described herein
can be used in the practice of the disclosed methods and apparatuses, certain
methods and apparatuses are described herein as examples and the scope of
25 coverage of this patent is not limited thereto. On the contrary, the present subject
matter covers all methods and apparatuses fairly falling within the scope of the
claims either literally or under the doctrine of equivalents. Further, unless defined
otherwise, all technical and scientific terms used herein have the same meaning as
commonly understood to one of ordinary skill in the art to which this disclosure
30 belongs.

[0048] In one example embodiment, the comparison between wear rate of a
sample soap bar for conventional manual process and process of the present
subject matter is given below. The working conditions for both the processes is
kept alike and are as follows:
5 Water temperature: 22 degrees C
Water hardness: 40FH
[0049] In the manual process the initial weight of the sample soap bar is
measured, followed by weight measurement after 500 rotations under running
water, and from these readings the percentage loss is calculated. The average
10 percentage loss, standard deviation and standard deviation as percentage was
calculated for four such readings as shown in Table 1.
Table 1: Wear Rate Determined by Manual Method
Test conditions Initial Weight after Percentage
weight 500 rotations loss
Water temperature - 22 degrees
Water hardness – 40 FH 125.05 109.55 12.39504198
Water temperature - 22 degrees
Water hardness – 40 FH 124.76 108.2 13.27348509
Water temperature - 22 degrees
Water hardness – 40 FH 125.95 104.78 16.80825724
Water temperature - 22 degrees
Water hardness – 40 FH 124.38 102.43 17.64753176
Average percentage loss = 15.03107902
15 Standard deviation = 2.584699534
Standard deviation as percentage = 17.19570186

[0050] Using the apparatus and the process of the present subject matter,
additional parameters such as speed of rotation, brush position from the apparatus
100 are taken into consideration. Total six readings were taken as shown in Table
2.
5 Table 2: Wear Rate Determined by Apparatus of Fig. 2a-2c
Test conditions Initial Weight Final Total Percentage
weight of holder weight loss loss
Water hardness – 40 FH
Water temperature - 22 degrees
Speed of rotation – (950 rpm,
without soap)
Brush position – 0 mm (from
surface for front brushes)
4 mm (from surface for side
brushes) 482.53 360 463 19.53 15.93895
Water hardness – 40 FH
Water temperature - 22 degrees
Speed of rotation – (950 rpm,
without soap)
Brush position – 0 mm (from
surface for front brushes)
4 mm (from surface for side
brushes) 481.72 360 463.21 18.51 15.20703
Water hardness – 40 FH Water temperature - 22 degrees Speed of rotation – (950 rpm, without soap)
Brush position – 0 mm (from
483.59 360 463.48 20.11 16.27154
surface for front brushes)

4 mm (from surface for side brushes)
Water hardness – 40 FH
Water temperature - 22 degrees
Speed of rotation – (950 rpm,
without soap)
Brush position – 0 mm (from
surface for front brushes)
4 mm (from surface for side
brushes) 482.1 360 462.08 20.02 16.3964
Water hardness – 40 FH
Water temperature - 22 degrees
Speed of rotation – (950 rpm,
without soap)
Brush position – 0 mm (from
surface for front brushes)
4 mm (from surface for side
brushes 482.28 360 462.15 20.13 16.46222
Water hardness – 40 FH
Water temperature - 22 degrees
Speed of rotation – (950 rpm,
without soap)
Brush position – 0 mm (from
surface for front brushes)
4 mm (from surface for side
brushes 481.92 360 461.86 20.06 16.45341
Average percentage loss = 16.12159167

Standard deviation = 0.488654522
Standard deviation as percentage = 3.031056315
[0051] As shown above the repeatability of the test is much higher and standard
deviation much lower when the test is conducted using the apparatus of the
5 present subject matter as compared to manual testing.
[0052] Although the subject matter has been described with reference to specific
embodiments, this description is not meant to be construed in a limiting sense.
Various modifications of the disclosed embodiments, as well as alternate
embodiments of the subject matter, will become apparent to persons skilled in the
10 art upon reference to the description of the subject matter. It is therefore
contemplated that such modifications can be made without departing from the present subject matter as defined.