TECHNICAL FIELD
[0001] The subject matter described herein in general relates to the field of stationery and writing implements, and in particular, relates to the field of chalk or board-based writing implements.
BACKGROUND OF INVENTION
[0002] In spite of digitalization of class rooms, the old-fashioned black-board is commonly practiced and preferred. The common chalk used for writing on such boards is made up of limestone combined with a binder such as clay. One of the most common problems with chalk is the tremendous amounts of chalk powder or dust that is generated by the persistent use of the chalk. The dust produced is both a nuisance as well a health-hazard as it stains the hand and consumption of such dust is considered unhealthy. Since, the chalk is often used by young adults and children, the repeated ingestion of such powder is not recommended. Though, thorough washing of hand is advocated after usage of chalks, the dust is found to be often persistent and is not easy to remove without usage of soap. Hence, chalk compositions that can render the hands clean or assist in the same are important for public use.
[0003] Furthermore, common methods for manufacture of chalk involves a time-consuming process involving moulding and sun-drying. The general output is about 100-144 pieces of chalk per batch, and hence any method to make this a continuous process is highly sought after. Accordingly, other known techniques such as extrusion for making chalks have been explored. KR101110360B1 discloses environment-friendly chalk with high strength. KR ‘360 also discloses an apparatus for extrusion of chalks using screw extruder. However, in order to ensure compatibility with screw extruder, the chalk composition essentially require greater amounts of binding agents such as polyvinyl alcohols and stearic acid, else chalks tend to have cracks and the final chalk product is prone to frequent breakage during use. KR100936293 also discloses a manufacturing method for chalk using natural minerals. Again, the extrusion method disclosed in KR ‘293 makes use of screw

type extruder which requires usage of high amounts of binder. Hence, methods for manufacture which allow fast and easy processing of chalk are sought after.
SUMMARY OF THE INVENTION
[0004] In an aspect of the present invention, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75.
[0005] In another aspect of the present invention, there is provided a process for preparing the chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, said process comprising steps of: a) contacting at least one clay with at least one surfactant to obtain a cleansing mix; b) contacting at least one binder with water to obtain a solution; c) contacting the solution with the cleansing mix to obtain a dough; d) compressing the dough to obtain a dough block; and e) extruding the dough block to obtain the chalk-based writing implement.
[0006] In yet another aspect of the present invention, there is provided a plodder for manufacturing a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, said apparatus comprising:
a mixer to:
mix at least one clay with at least one surfactant to obtain a cleansing mix; and
mix the cleansing mix with a solution of at least one binder and water to obtain a dough
a compactor to compress the dough to obtain a dough block; and
a hydraulic extruder to extrude the dough block to obtain the chalk-based writing implement, the hydraulic extruder comprising:

a chalk die with at least one orifice in the range of 7-9 mm; and
a hydraulic piston to compress the dough block with a pressure of 2-3 kg/cm2 to
press the dough block through the at least one orifice of the chalk die to obtain the
chalk-based writing implement.
[0007] These and other features, aspects, and advantages of the present subject
matter will be better understood with reference to the following description and
appended claims. This summary is provided to introduce a selection of concepts in
a simplified form. This summary is not intended to identify key features or
essential features of the claimed subject matter, nor is it intended to be used to limit
the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The detailed description is described with reference to the accompanying
figures. The same numbers are used throughout the drawings to reference like
features and components.
[0009] Figure 1 illustrates the process for manufacturing the chalk-based writing
implement, in accordance with an implementation of the present subject matter.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Those skilled in the art will be aware that the present disclosure is subject to
variations and modifications other than those specifically described. It is to be
understood that the present disclosure includes all such variations and
modifications. The disclosure also includes all such steps, features, compositions,
and compounds referred to or indicated in this specification, individually or
collectively, and any and all combinations of any or more of such steps or features.
Definitions
[0011] For convenience, before further description of the present disclosure,
certain terms employed in the specification, and examples are delineated here.
These definitions should be read in the light of the remainder of the disclosure and
understood as by a person of skill in the art. The terms used herein have the
meanings recognized and known to those of skill in the art, however, for
convenience and completeness, particular terms and their meanings are set forth
below.

[0012] The articles “a”, “an” and “the” are used to refer to one or to more than one
(i.e., to at least one) of the grammatical object of the article.
[0013] The terms “comprise” and “comprising” are used in the inclusive, open
sense, meaning that additional elements may be included. It is not intended to be
construed as “consists of only”.
[0014] Throughout this specification, unless the context requires otherwise the
word “comprise”, and variations such as “comprises” and “comprising”, will be
understood to imply the inclusion of a stated element or step or group of element or
steps but not the exclusion of any other element or step or group of element or
steps.
[0015] The term “including” is used to mean “including but not limited to”.
“Including” and “including but not limited to” are used interchangeably.
[0016] Ratios, concentrations, amounts, and other numerical data may be presented
herein in a range format. It is to be understood that such range format is used
merely for convenience and brevity and should be interpreted flexibly to include
not only the numerical values explicitly recited as the limits of the range, but also
to include all the individual numerical values or sub-ranges encompassed within
that range as if each numerical value and sub-range is explicitly recited. For
example, a temperature range of about 25–35 ℃ should be interpreted to include
not only the explicitly recited limits of about 25 ℃ to about 35 ℃, but also to
include sub-ranges, such as 25–30 ℃, 27–135 ℃, and so forth, as well as individual
amounts, including fractional amounts, within the specified ranges, such as 25.2 ℃,
and 34.5 ℃, for example.
[0017] The term “at least one” is used to mean one or more and thus includes
individual components as well as mixtures/combinations.
[0018] The term “clay-based additive” or “clay” has been used interchangeably as
part of the present disclosure. The clay may be selected from the group consisting
of kaolin clay, calcium carbonate, porbandar clay, china clay, and combinations
thereof.
[0019] Unless defined otherwise, all technical and scientific terms used herein have
the same meaning as commonly understood by one of ordinary skill in the art to

which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.
[0020] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally-equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein.
[0021] As mentioned previously, the existing methods of manufacturing chalk and the chalk compositions in general suffer from various drawbacks. The existing chalk compositions generate a lot of dust and are difficult to wash off by mere rinsing with water. The present disclosure attempts to provide a chalk composition that allows easy cleansing post-wash. Furthermore, the composition can be manufactured in continuous process using a plodder apparatus as described herein. [0022] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75. In another embodiment of the present disclosure, the at least one binder to the at least one clay weight ratio is in the range of 1:20 – 1:68. In yet another embodiment of the present disclosure, the at least one binder to the at least one clay weight ratio is in the range of 1:30 – 1:60. [0023] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one binder to the at least one surfactant weight ratio is in the range of 1:1.2 – 1:15. In another embodiment of the present disclosure, the at least one binder to the at least one surfactant weight ratio is in the range of 1:3 – 1:13. In another embodiment of the present disclosure, the at least one binder to the at least one surfactant weight ratio is in the range of 1:6 – 1:11.

[0024] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one surfactant to the at least one clay weight ratio is in the range of 1:4 – 1:12.5. In another embodiment of the present disclosure, the at least one surfactant to the at least one clay weight ratio is in the range of 1:6 – 1:10.5. In another embodiment of the present disclosure, the at least one surfactant to the at least one clay weight ratio is in the range of 1:7 – 1:9.5.
[0025] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and water to the at least one clay weight ratio is in the range of 1:5 – 1:12.5. In another embodiment of the present disclosure, water to the at least one clay weight ratio is in the range of 1:6 – 1:11.5. In another embodiment of the present disclosure, water to the at least one clay weight ratio is in the range of 1:7 – 1:10.5.
[0026] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one clay is selected from the group consisting of kaolin clay, calcium carbonate, porbandar clay, china clay, and combinations thereof. In another embodiment of the present disclosure, the at least one clay is kaolin clay. In yet another embodiment of the present disclosure, the at least one clay is porbandar clay. In an alternate embodiment of the present disclosure, the at least one clay is a combination of kaolin clay and porbandar clay. [0027] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one binder is selected from the group consisting of starch, polyvinyl alcohol, sodium silicate, and combinations

thereof. In another embodiment of the present disclosure, the at least one binder is starch.
[0028] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one surfactant is selected from the group consisting of sodium lauryl ether sulfate, food grade surfactants, and combinations thereof. In another embodiment of the present disclosure, the at least one surfactant is sodium lauryl ether sulfate. In yet another embodiment of the present disclosure, the at least one surfactant is a food grade surfactant. The food grade surfactants may be selected but not limited to known surfactants such as commonly used sorbitan esters.
[0029] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and at least one clay has a weight percentage in the range of 60 – 75% with respect to the composition. In another embodiment of the present disclosure, the at least one clay has a weight percentage in the range of 62 – 73% with respect to the composition. In yet another embodiment of the present disclosure, the at least one clay has a weight percentage in the range of 65 – 70% with respect to the composition.
[0030] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one binder has a weight percentage in the range of 1 – 5% with respect to the composition. In another embodiment of the present disclosure, the at least one binder has a weight percentage in the range of 1.5 – 4.5% with respect to the composition. In yet another embodiment of the present disclosure, the at least one binder has a weight percentage in the range of 2 – 4% with respect to the composition.

[0031] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one surfactant having weight percentage in the range of 6 – 15% with respect to the composition. In another embodiment of the present disclosure, the at least one surfactant having weight percentage in the range of 8 – 13%. In yet another embodiment of the present disclosure, the at least one surfactant having weight percentage in the range of 9 – 12%.
[0032] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and water having weight percentage in the range of 6 – 12% with respect to the composition. In another embodiment of the present disclosure, water having weight percentage in the range of 7 – 11% with respect to the composition. In yet another embodiment of the present disclosure, water having weight percentage in the range of 8 – 10% with respect to the composition. [0033] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay having weight percentage in the range of 60 – 75% with respect to the composition; at least one binder having weight percentage in the range of 1 – 5% with respect to the composition; at least one surfactant having weight percentage in the range of 6 – 15% with respect to the composition; and water having weight percentage in the range of 6 – 12% with respect to the composition, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75.
[0034] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75 and the composition further comprises at least one excipient selected from the group consisting of fragrance, colorant, whitener, antimicrobial active, and combinations thereof. In another embodiment of the

present disclosure, the fragrance is selected from well-known fragrances in the art. In yet another embodiment of the present disclosure, the colorant is selected from well-known colorants in the art. In an alternate embodiment of the present disclosure, the antimicrobial active is selected from the group consisting of bisguanidine, diphenyl compounds, benzyl alcohols, trihalocarbanilides, quaternary ammonium compounds, ethoxylated phenols, phenolic compounds and combinations thereof. In yet another alternate embodiment of the present disclosure, the bisguanidine is chlorhexidine digluconate and phenolic compounds is selected from the group consisting of p-chloro-m-xylenol, 2,4,4'-trichloro-2'-hydroxy-diphenylether, and combinations thereof.
[0035] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; water; and at least one excipient, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one excipient is whitener.
[0036] In an embodiment of the present disclosure, there is provided a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; water; and at least one excipient, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, and the at least one excipient is whitener selected from the group consisting of calcium carbonate, titanium dioxide, and combinations thereof.
[0037] In an embodiment of the present disclosure, there is provided a process for preparing the chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, said process comprising steps of: a) contacting at least one clay with at least one surfactant to obtain a cleansing mix; b) contacting at least one binder with water to obtain a solution; c) contacting the solution with the cleansing mix to obtain a dough; d) compressing the dough to obtain a dough block; and e) extruding the dough block to obtain the chalk-based writing implement.

[0038] In an embodiment of the present disclosure, there is provided a process for preparing the chalk-based writing implement as described herein, wherein contacting the at least one clay with the at least one surfactant is carried out at a temperature in the range of 25 – 35 ℃ for a period of 5 – 15 minutes at a stirring speed of 25 – 35 rpm under a pressure of 1 – 2 bar to obtain the cleansing mix. In another embodiment of the present disclosure, contacting the at least one clay with the at least one surfactant is carried out at a temperature in the range of 27 -32 ℃ for a period of 7 – 13 minutes at a stirring speed of 27 – 32 rpm under a pressure of 1.1 – 1.9 bar to obtain the cleansing mix. In yet another embodiment of the present disclosure, contacting the at least one clay with the at least one surfactant is carried out at a temperature in the range of 28 -31 ℃ for a period of 8 – 14 minutes at a stirring speed of 28 – 31 rpm under a pressure of 1.2 – 1.7 bar to obtain the cleansing mix.
[0039] In an embodiment of the present disclosure, there is provided a process for preparing the chalk-based writing implement as described herein, wherein contacting the at least one binder with water is carried out at a temperature in the range of 25 –35 ℃ for a period of 5 – 15 minutes at a stirring speed of 25 – 35 rpm under a pressure of 1 – 2 bar to obtain the solution. In another embodiment of the present disclosure, contacting the at least one binder with water is carried out at a temperature in the range of 27 -32 ℃ for a period of 7 – 13 minutes at a stirring speed of 27 – 32 rpm under a pressure of 1.1 – 1.9 bar to obtain the solution. In yet another embodiment of the present disclosure, contacting the at least one binder with water is carried out at a temperature in the range of 28 -31 ℃ for a period of 8 – 14 minutes at a stirring speed of 28 – 31 rpm under a pressure of 1.2 – 1.7 bar to obtain the solution.
[0040] In an embodiment of the present disclosure, there is provided a process for preparing the chalk-based writing implement as described herein, wherein contacting the solution with the cleansing mix is carried out at a temperature in the range of 25 – 35 ℃ for a period of 5 – 15 minutes at a stirring speed of 25 – 35 rpm under a pressure of 1 – 2 bar to obtain the dough. In another embodiment of the present disclosure, contacting the solution with the cleansing mix is carried out at a

temperature in the range of 27 -32 ℃ for a period of 7 – 13 minutes at a stirring speed of 27 – 32 rpm under a pressure of 1.1 – 1.9 bar to obtain the dough. In yet another embodiment of the present disclosure, contacting the solution with the cleansing mix is carried out at a temperature in the range of 28 -31 ℃ for a period of 8 – 14 minutes at a stirring speed of 28 – 31 rpm under a pressure of 1.2 – 1.7 bar to obtain the dough.
[0041] In an embodiment of the present disclosure, there is provided a process for preparing the chalk-based writing implement as described herein, wherein stirring can be carried out using mixers known in the art such as sigma mixer, paddle mixer, and blender such as ribbon blender.
[0042] In an embodiment of the present disclosure, there is provided a plodder (apparatus) for manufacturing a chalk-based writing implement comprising: at least one clay; at least one binder; at least one surfactant; and water, wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75, said apparatus comprising:
a mixer to:
mix at least one clay with at least one surfactant to obtain a cleansing mix; and
mix the cleansing mix with a solution of at least one binder and water to obtain a dough
a compactor to compress the dough to obtain a dough block; and
a hydraulic extruder to extrude the dough block to obtain the chalk-based writing implement, the hydraulic extruder comprising:
a chalk die with at least one orifice in the range of 7-9 mm; and
a hydraulic piston to compress the dough block with a pressure of 2-3 kg/cm2 to press the dough block through the at least one orifice of the chalk die to obtain the chalk-based writing implement.
[0043] In an embodiment of the present invention, there is provided a plodder as described herein, wherein the mixer further comprises a motor having a speed in the range of 25 – 35 rpm. In another embodiment of the present disclosure, the

mixer further comprises a motor having a speed in the range of 27 – 32 rpm. In another embodiment of the present disclosure, the mixer further comprises a motor having a speed in the range of 28 – 31 rpm.
[0044] In an embodiment of the present invention, there is provided a plodder as described herein, wherein the mixer is to contact the at least one clay with the at least one surfactant at a temperature in the range of 25 – 35 ℃ for a period of 5 – 15 minutes, under a pressure of 1 – 2 bar to obtain the cleansing mix, and wherein the at least one clay is mixed with the at least one surfactant at a stirring speed of 25 – 35 rpm. In another embodiment of the present disclosure the mixer is to contact the at least one clay with the at least one surfactant at a temperature in the range of 27 -32 ℃ for a period of 7 – 13 minutes, under a pressure of 1.1 – 1.9 bar to obtain the cleansing mix, and wherein the at least one clay is mixed with the at least one surfactant at a stirring speed of 27 – 32 rpm. In yet another embodiment of the present disclosure, the mixer is to contact the at least one clay with the at least one surfactant at a temperature in the range of 28 -31 ℃ for a period of 8 – 14 minutes, under a pressure of 1.2 – 1.7 bar to obtain the cleansing mix, and wherein the at least one clay is mixed with the surfactant at a stirring speed of 28 – 31 rpm. [0045] In an embodiment of the present invention, there is provided a plodder as described herein, wherein the mixer further is to contact the solution with the cleansing mix at a temperature in the range of 25 – 35 ℃ for a period of 5 – 15 minutes, under a pressure of 1 – 2 bar, at the stirring speed of 25 – 35 rpm to obtain the dough. In another embodiment of the present disclosure, the mixer further is to contact the solution with the cleansing mix at a temperature in the range of 27 – 32 ℃ for a period of 7 – 13 minutes, under a pressure of 1.1 – 1.9 bar, at the stirring speed of 27 – 32 rpm to obtain the dough. In yet another embodiment of the present disclosure, the mixer further is to contact the solution with the cleansing mix at a temperature in the range of 28 – 31 ℃ for a period of 8 – 12 minutes, under a pressure of 1.2 – 1.8 bar, at the stirring speed of 28 – 31 rpm to obtain the dough. [0046] In an embodiment of the present invention, there is provided a plodder as described herein, wherein the compactor further comprises: a chamber for holding the dough;

a compressing piston to compress the dough within the chamber with a pressure of
2-3 kg/cm2 to obtain the dough block; and
an ejector block coupled to the chamber to provide the dough block.
[0047] In an embodiment of the present invention, there is provided a plodder as
described herein, wherein the plodder is able to extrude chalks at a rate of 300 –
500 chalks/min.
EXAMPLES [0048] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. 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 belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may apply. [0049] The chalk-based writing implement as described herein provides convenience of easy-wash for the user. The presence of surfactant allows the user to rinse the chalk-dust with water. The surfactant allows effective cleansing with rich lather. Furthermore, the process for manufacture of the implement utilizing the plodder as described herein allows the continuous manufacture of chalk via extrusion method.
Example 1: Chalk-based writing implement
[0050] The implement was prepared using the composition as described in the
Table 1 below.

[0051] As is clear from Table 1, the above mentioned economical ingredients can be conveniently used to obtain the writing implement. As has been mentioned in background section, such writing implements are prone to frequent breakage. However, the mentioned ranges of binder to the clay along with the addition of water allows one to obtain a stable writable implement which can manufactured by extrusion process as described below.
Example 2: General protocol for manufacture of the writing implement using the plodder of present invention
[0052] The steps for manufacture of the chalk-based writing implement are as follows: a) Take a sigma mixer with 150 kg working capacity and mix clay and surfactant for 10 minutes to obtain cleansing mix; b) Separately mix starch and water to obtain a starch solution; c) Mix starch solution of step b) into cleansing mix of step a) while maintaining temperature of sigma mixer at 25 – 35ºC. Continue mixing for 10 minutes to obtain chalk dough; d) Place the chalk dough of step c) into compactor and compress at a pressure of 2-3 kg/cm2 to obtain dough block; e) Place the dough block of step d) into hydraulic extruder and compress with hydraulic piston with a pressure of 2-3 kg/cm2 such that dough block passes through the chalk die with an orifice of 7-9 mm to provide chalk piece and f) Dry the chalk pieces to obtain chalk (writing implement).
[0053] The soap making extruders as used in the industry are screw-based extruders where the function of screw is to convey the soap noodles until the orifice while continuously compacting the soap noodle mix to avoid the air crack. In chalk making process extruder required is such that some air is retained in the mix during extrusion. Complete loss of air during compaction makes the final chalk

brittle after drying. Also, the compaction pressure as required by soap is higher i.e. 3-6 kg/cm2 whereas in chalk making the pressure is lower. If a screw extruder is used for making chalk then more compaction is received and heat is generated during the process which results in cracked chalks.
[0054] The chalk-based writing implement as explained in the preceding paragraphs may be manufactured through various manufacturing units. An example of such a manufacturing unit is illustrated in FIG. 1. FIG. 1 illustrates an exemplary manufacturing unit 100. The manufacturing unit 100 may implement a series of stages or steps for manufacturing the chalk-based writing implement as described in the preceding paragraphs. In the present example, the manufacturing unit 100 further comprises a mixing unit 102, a compacting unit 104 and an extruding unit 106. Each of the mixing unit 102, the compacting unit 104 and the extruding unit 106 may be either integrally connected to each other or may be in communication with each other through a conveying mechanism (not shown in FIG. 1). The manufacturing unit 100 as depicted in FIG. 1 is exemplary and is one of many other examples that may be used for manufacturing the chalk-based writing implement. It should be further noted that the various stages have been shown to be implemented or performed through the respective units 102, 104 and 106. It should be however noted that the various stages may be combined and performed by a single unit or may be further sub-divided into further steps to be performed by additional units, without deviating from the scope of the present subject matter. [0055] The mixing unit 102 further comprises an external container 108. The mixing unit 102 may further be provided with a stirring element 110. The mixing unit 102 may be utilized for preparing chalk dough 112. The chalk dough 112 may be a semi-solid mass and malleable. In operation, specific volumes of clay-based additive and a surfactant may be added into the mixing unit 102. The stirring element 110 may then be actuated for mixing the clay-based additive and the surfactant to obtain a cleansing mix. The clay-based additive and the surfactant may be mixed for about 10-15 minutes. Once the cleansing mix is obtained, a solution of at least one binder and water may be further added into the external container 108 for obtaining the chalk dough 112. In one example, the mixing of the

solution with the cleansing mix may be carried out at a temperature in the range of about 27℃ to about 32 ℃. The mixing of the solution and the cleansing mix may be performed for about 7 – 13 minutes at a stirring speed of 27 – 32 rpm. In one example, the mixing of the cleansing mix and the solution may be affected in a controlled pressure environment under a pressure of 1.1 – 1.9 bar. In yet another example, the mixing of the solution with the cleansing mix is carried out for at a temperature in the range of 28 -31 ℃ for a period of 8 – 14 minutes at a stirring speed of 28 – 31 rpm under a pressure of 1.2 – 1.7 bar to obtain the dough. In another example, the binder to the clay weight ratio is in the range of 1:12 – 1:75. The stirring element 110 may be any stirring mechanism which enables mechanical agitation of contents in the external container 108. In one example, the stirring element 110 may be a sigma-mixer.
[0056] The chalk dough 112 once obtained may be provided to the compacting unit 104. The compacting unit 104 may further include a piston head 114. The piston head 114 is movable within a compacting chamber 116. The movement of the piston head 114 when actuated may move into the compacting chamber 116 to compress any matter present therein. In one example, the piston head 114 may be actuated mechanically or hydraulically. In operation, the chalk dough 112 may be transported into the compacting chamber 116 of the compacting unit 104. The chalk dough 112 may be transported into the compacting chamber 116 through conveying mechanism or may be manually transported from the mixing unit 102 into the compacting chamber 116. Once the chalk dough 112 is positioned into the compacting chamber 116, the piston head 114 may be actuated. Once actuated, the piston head 114 may bear down applying a deforming force onto the chalk dough 112 present within the compacting chamber 116. In one example, the deforming force may be in the range of 2-3 kg/cm2.
[0057] Since the chalk dough 112 is malleable, the applicable of the deforming force changes the shape and configuration of the chalk dough 112 to form a dough block 118. The shape of the dough block 118 may depend on the internal shape of the compacting chamber 116. Once the dough block 118 is formed, it may be

retrieved from the compacting unit 104 through an ejector 120. In one example, the shape of the ejector 120 may further form the dough block 118.
[0058] The dough block 118 once obtained may be provided to the extruding unit 106, either through a conveying mechanism (not shown in FIG. 1) or manually from the compacting unit 104. The extruding unit 106 may further include an extruding piston 122. The extruding piston 122 may be movable into a mould unit 124. The extruding piston 122 and the mould unit 124 may be such that their respective profile and shape may be complimentary with respect to each other. This is to say that the extruding piston 122 when fully inserted would be completely accommodated within the space of the mould unit 124.
[0059] In operation, the dough block 118 is positioned into the mould unit 124. Once the dough block 118 is placed in the mould unit 124, the extruding piston 122 may be actuated. As the extruding piston 122 moves, it abuts and applies an extruding force onto the dough block 118. The dough block 118 under the extruding force may deform. As the dough block 118 deforms, the continuous application of the extruding force by the extruding piston 122 forces the dough block 118 through an extrusion channel 130 to provide a chalk-based writing implement 128. The shape of the extrusion channel 130 may be predefined. As the writing implement 128 is forced out of the extrusion channel 130, the shape of the writing implement 128 conforms to the shape of the extrusion channel 130.
Advantages of the present disclosure:
[0060] The present disclosure reveals a chalk-based writing implement that allows
easy rinsing of the dust that may accumulate on user’s hands upon use. The
implement comprising surfactant that allows efficient cleansing with rich lather.
Also described is a process for convenient manufacture of the implement. The
provided plodder allows continuous manufacture of chalk at a rate of 300-500
chalks/min.

I/We Claim:
1. A chalk-based writing implement comprising:
a) at least one clay;
b) at least one binder;
c) at least one surfactant; and
d) water,
wherein the at least one binder to the at least one clay weight ratio is in the range of 1:12 – 1:75.
2. The chalk-based writing implement as claimed in claim 1, wherein the at least one surfactant to the at least one clay weight ratio is in the range of 1:4 – 1:12.5.
3. The chalk-based writing implement as claimed in claim 1, wherein the at least one clay is selected from the group consisting of kaolin clay, calcium carbonate, porbandar clay, china clay, and combinations thereof.
4. The chalk-based writing implement as claimed in claim 1, wherein the at least one binder is selected from the group consisting of starch, polyvinyl alcohol, sodium silicate, and combinations thereof.
5. The chalk-based writing implement as claimed in claim 1, wherein the at least one surfactant is selected from the group consisting of sodium lauryl ether sulfate, food grade surfactants, and combinations thereof.
6. The chalk-based writing implement as claimed in any of the claims 1- 5, said implement comprising:

a) at least one clay having weight percentage in the range of 60 – 75% with respect to the composition;
b) at least one binder having weight percentage in the range of 1 – 5% with respect to the composition;
c) at least one surfactant having weight percentage in the range of 6 – 15% with respect to the composition; and
d) water having weight percentage in the range of 6 – 12% with respect to the composition.

7. The chalk-based writing implement as claimed in any of the claims 1-6, wherein the composition further comprises at least one excipient selected from the group consisting of fragrance, colorant, whitener, antimicrobial active, and combinations thereof.
8. The chalk-based writing implement as claimed in claim 7, wherein the whitener is selected from the group consisting of calcium carbonate, titanium dioxide, and combinations thereof.
9. A process for preparing the chalk-based writing implement as claimed in any of the claims 1-8, said process comprising the steps of:

a) contacting at least one clay with at least one surfactant to obtain a cleansing mix;
b) contacting at least one binder with water to obtain a solution;
c) contacting the solution with the cleansing mix to obtain a dough;
d) compressing the dough to obtain a dough block; and
e) extruding the dough block to obtain the chalk-based writing implement.

10. The process as claimed in claim 9, wherein contacting the at least one clay with the at least one surfactant is carried out at a temperature in the range of 25 – 35 ℃ for a period of 5 – 15 minutes at a stirring speed of 25 – 35 rpm under a pressure of 1 – 2 bar to obtain the cleansing mix.
11. The process as claimed in claim 9, wherein contacting the at least one binder with water is carried out at a temperature in the range of 25 -35 ℃ for a period of 5 – 15 minutes at a stirring speed of 25 – 35 rpm under a pressure of 1 – 2 bar to obtain the solution.
12. The process as claimed in claim 9, wherein contacting the solution with the cleansing mix is carried out at a temperature in the range of 25 -35 ℃ for a period of 5 – 15 minutes at a stirring speed of 25 – 35 rpm under a pressure of 1 – 2 bar to obtain the dough.

13. A plodder for manufacturing a chalk-based writing implement, the
apparatus comprising:
a mixer to:
mix at least one clay with at least one surfactant to obtain a cleansing mix; and
mix the cleansing mix with a solution of at least one binder and water to obtain a dough
a compactor to compress the dough to obtain a dough block; and
a hydraulic extruder to extrude the dough block to obtain the chalk-based writing implement, the hydraulic extruder comprising:
a chalk die with at least one orifice in the range of 7-9 mm; and
a hydraulic piston to compress the dough block with a pressure of 2-3 kg/cm2 to press the dough block through the at least one orifice of the chalk die to obtain the chalk-based writing implement.
14. The plodder as claimed in claim 13, wherein the mixer further comprises a motor having a speed in the range of 25 – 35 rpm.
15. The plodder as claimed in claim 14, wherein the mixer is to contact the at least one clay with the at least one surfactant at a temperature in the range of 25 -35 ℃ for a period of 5 – 15 minutes, under a pressure of 1 – 2 bar to obtain the cleansing mix, and wherein the one clay is mixed with the surfactant at a stirring speed of 25 – 35 rpm.
16. The plodder as claimed in claim 14, wherein the mixer further is to contact the solution with the cleansing mix at a temperature in the range of 25 – 35 ℃ for a period of 5 – 15 minutes, under a pressure of 1 – 2 bar, at the stirring speed of 25 – 35 rpm to obtain the dough.
17. The plodder as claimed in claim 13, wherein the compactor further comprises:
a chamber for holding the dough;

a compressing piston to compress the dough within the chamber with a pressure of 2-3 kg/cm2 to obtain the dough block; and
an ejector block coupled to the chamber to provide the dough block.