1. A phase change material comprising a fatty acid present in an amount ranging from 20% to SO%, Dodecanol present in an amount ranging from 20% to SO%, a carbon powder present in an amount ranging from 1 % to 2% or combination(s) thereof.

2. The phase change material as claimed in claim 1 , wherein the transition temperature of said phase change material ranges from 10 to 25 degree celsius.

3. The phase change material as claimed in claim 1, wherein the solidification temperature of said phase change material ranges from 19 to 4 degree celsius.

4. The phase change material as claimed in claim 1, wherein the latent heat of said phase change material range from 150 to 160kJlkg.

5. The phase change material as claimed in claim 1, wherein said material is thermally stable and is capable of bearing to more than 500 heating and cooling cycles.

6. The phase change material as claimed in claim 1, wherein said fatty acid comprises saturated fatty acid selected from a group comprising capric acid, lauric acid, myristic acid, palmitic acid, stearic acid or combination(s) thereof.

7. The phase change material as claimed in claim 1, wherein said carbon powder is graphite.

8. The phase change material as claimed in claim 1, wherein said phase change material is in the form of gelled microcapsules.

9. The phase change material as claimed in claim 1, wherein said phase change is optionally mixed with a hydrogel.

10. The phase change material as claimed in claim 8, wherein the shell material of said micro capsule is made of poly urea formaldehyde.

11. The phase change material as claimed in claim 8, wherein the size of micro capsule ranges from 13 to 97 pm.

12. The phase change material as claimed in claim 1, wherein said phase change material provides thermal comfort for about 2 to 2.5 hours at about 40 to 48' C temperature range.

13. A thermal garment system comprising a phase change material as claimed in claim(s) 1 to 12.

14. The thermal garment system as claimed in claim 13, wherein said garment comprising a vest having front (1) and back panels (6) for substantially covering and conforming to the chest and back of said user's torso, said front (1) and back panels (6) attached to each other from top while defining an opening through which said user's head extends (4), when worn, plurality of straps (5) extending from said back side adapted to be tightened to said front side, a closing means (3) present in said front side. a plurality of pocket(s) integrally attached to at least one of said panel(s), each of said pockets having an open end and a closed end defining an inner cavity adapted to receive and support at least one phase change material pack therein.

15. The thermal garment system as claimed in claim 13, wherein said pocket comprises a body side surface (1) and an ambient side surface (2) creating an interstitial space (7) for locating a phase change material pack therein, said surface(s) comprises atleast a poly urethane foam (4,5), atleast a cotton fabric lining (6,7).

16. The thermal garment system as claimed in claim 13, wherein the thickness of said poly urethane foam present towards body surface ranges from 4mm to 6mm.

17. The thermal garment system as claimed in claim 13, wherein the thickness of said poly urethane foam present towards body surface ranges from I Olnm to 201nm.

18. The thermal garment system as claimed in claim 13, wherein said garment enables controlled heat transfer rate in the range of 70 to 160 w/m2. Dated this 1 3th day of September 201 3 Suvarna Pandey Of S. Majumdar & Co. (Applicant's Agent)

FIELD OF THE INVENTION
The present invention relates to a multi transformation broad temperature range phase change
material/composition for body cooling device(s).
The Invention also provides a body temperature regulating garment and more particularly to a
thermal garment system comprising said phase change material.
In the present embodiment, the invention has been described the thennal garment system with
reference to a cool vest, however such description should not be considered as restricting the
scope of the present invention. Further it would be possible for a person skilled in the art to
practice the present invention or use the present phase change material in preparing the cool
garments like cap, scarf and others, without departing from the scope of the present
invention.
BACKGROUND & PRIOR ART OF - THE INVENTION
Heat stress refers to the combination of factors that increase the body's core temperature, such
as environmental conditions, clothing and metabolic rate. Heat stress disorders include heat
cramps, heat exhaustion-and heat stoke.
When an individual's heat balance is compromised, the body will try to direct heat away from
the core by increasing blood flow to the skin. When body cannot sufficiently cool itself,
injuries related to heat stress occur. Heat stress is often a significant risk for individuals who
perform hard work in a hot and/or humid environmen~s, for example, firefighters, police
officers, military personnel, athletes, factorylplant workers (e.g., welders), construction
workers (e.g., roofers), etc.
Often most heat related illness is treated after the individual's body has reached active
hyperthermia. Numerous methods of rapidly cooling an individual's core body temperature
have been effectively employed in the past. Some of these include: ice packs or towels, ice
water immersion, whole-body liquid cooling garments, head cooling units, cool water spray,
etc. The most effective placement of ice or cold packs has been found on the skin of the neck
and underarms. This promotes rapid cooling of the blood. Few prior art devices or methods
have attempted to pre\ ent heat stress related illness before it occurs.
While some prior art garments do disclose the use of attachable thermal packs for
engendering a change in the body temperature of the user, these thermal packs must be stored
in a cooling chamber until such time as they need to be used. This severely limits the
portability and practicality of such garments. Often, emergency stations and vehicles are
limited in space and cannot afford to include cooling chambers as they take up valuable
workspace and other resources.
To minimize incidents of heat strain, heat stress, and heat stroke, most work areas are airconditioned
and/or individuals are provided with a locally-cooled environment in the form of
a cooling garment, e.g., suit or vest, having cool water circulation or equivalent. Active
cooling between work periods and air flow through a worker's uniform are additional ways to
minimize incidents of heat-related injuries. Cooling garments such as cooling vests and
cooling suits generally include ice or a phase change material as a medium to reduce the
user's elevated temperature and, in so doing, transform the cooling material from solid state to
liquid state. In order to cope with a heat production of 300 Watts for a duration of one hour, a
cooling suit typically has a weight of approximately 3 kilograms. The use of cooling
garments may be problematic due to the high extra weight for some applications, difficulties
with arranging a good heat transport from the body to the garment, and the time and effort
needed to reactivate the garment after use, e.g., half an hour in ice-cold water. In addition, if
ice is used for cooling, the vasoconstriction effect by restricting the blood flow counteracts
the cooling capacity of ice.
Other approaches toward reducing core temperature relate to increased ambient airflow
though the suit to enhance the body's cooling mechanism through sweating. By removing the
humid air in the suit, more evaporation of sweat can take place and consequently give the
body more cooling. The problem is that to be effective, high airflow of 200-300 literslminute
is needed, and the ambient air temperature must be some gradient below skin temperature.
Portable air cylinder worn by the user (as with a self contained breathing apparatus (SCBA)
commonly employed by fire fighters and other first responders) would reduce the duration of
the SCBA too much. However, heavy wearable air cylinders would reduce the user's
movements and operating range.
GB2093981 discloses an evaporative panel for use in human body cooling comprising a
flexible reticulated, e.g. woven, structure including wicking and void continua, and an
impermeable plastics film or laminate envelope surrounding the structure. The proposed
working fluid is water, which is a good choice due to its high latent heat of evaporation and
non-toxicity. However water has a low vapour pressure which means that a substantial
vacuum level needs to be maintained within the envelope for useful evaporation to occur
within the required temperature range for human body cooling. The need for evacuation of
the envelope has the disadvantage though that there is a danger of the woven structure
collapsing into its vapour flow voids and thereby preventing operation of the heat pipe cycle.
The system in this document limits the area of the panel over which efficient heat transfer
into the working fluid held by the wicking can take place.
W02009138713 discloses a wearable apparatus for cooling the human body which
comprises an airflow creation means, a controller for controlling the created airflow, at least
one duct connected to the airflow creation means, wherein the duct comprises a porous
portion configured to direct a flow of air to a region of the human body and wherein in
operation the controller means controls the airflow to intermittently allow air to flow through
the duct. However, the system is highly complica~ed. Further, in hot tropical eliminate high
temperature of ambient air restricts its cooling effectiveness.
Other evaporative cooling inventions are taught by US Patents Nos. 6,295,648, 6,276,155 and
6,257,011. These patents provide a shirt with channels which absorb sweat andlor
evaporative liquid and a device to then move air through the channels to create the cooling
effect. While these inventions may provide evaporative cooling to a human or animal user of
the invention, but they lack the simplicity.
US Patent Application No. 200310208831 discloses an evaporative cooling gannent
manufactured from a multi-layered fabric with chambers where holes created by sewing or
stitching channel the water into the chambers. The system lacks simplicity.
Further, the presently available phase change material for vest and other cooling garments
have narrow melting temperature range. These phase change material absorbs heat of body at
constant temperature and due to which these can't be used for sedentary, mild working and
hard working conditions.
Hence, there still remains a need for a phase change material which is effective in reducing
heat stress in severe heat conditions and which has wide melting temperature range and
should have high thermal stability. Also, there is a need of cooling garments comprising said
phase change material.
OBJECTIVE OF THE INVENTION
A basic object of the present invention is to overcome the disadvantages/drawbacks of the
known art.
Yet another object of the present invention is to provide a phase change material.
Yet another object of the present invention is to provide a phase change material with a wide
temperature melting range varying between 10 to 25 degree celsius.
Yet another object of the present invention is to provide a phase change material with a
solidification temperature ranging from 19 degree celsius to 4 degree celsius.
Yet another object of the present invention is to provide a phase change material with a
latent heat from 150 to 160kj/kg.
Yet another object of the present invention is to provide a thermally stable phase change
material.
Yet another object of the present invention is to provide a cooling garment comprising said
phase change material.
SUMMARY OF THE PRESENT INVENTION
The present invention provides a phase change material comprising a fatty acid present in an
amount ranging from 20 % to SO%, Dodecanol present in an amount ranging from 20% to
SO%, a carbon powder present in an amount ranging from 1% to 2% or combination(s)
thereof.
In another aspect of the Invention, there is provided a thermal garment system comprising
above said phase change material, for a user to provide cooling of the user's upper torso. The
thermal garment system compises a vest having front ( I ) and back panels (6) for substantially
covering and conforming to the chest and back of said user's torso, said front (1) and back
panels (6) attached to each other from top while defining an opening through which said
user's head extends (4), when worn, plurality of straps (5) extending from said back side
adapted to be tightened to said front side, a closing means (3) present in said front side, a
of pocket(s) integrally attached to at least one of said panel(s), each of said pockets
having an open end and a closed end defining an inner cavity adapted to receive and support
at least one phase change material pack therein.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates DSC curve of phase change material (PCM)
Figure 2 illustrates DSC characterization of PCM after 500 heating cooling cycles
Figure 3 illustrates SEM of microencapsulated PCM
Figure 4 illustrates SEM of microencapsulated PCM
Figure 5 (a) illustrates front view of the cool vest, 5 (b) illustrates cool cap
Figure 6 illustrates pockets in the PCM cool vest
Figure 7 illustrates front and back view of the phase change material cool vest
Figure 8 illustrates pocket to hold PCM packs.
Figure 9 illustrates DSC curve of phase change material (PCM) produced in example 3.
Figure 10 illustrates DSC curve of phase change material (PCM) produced in example 4.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Accordingly, the Invention provides a phase change material1 composition which is effective
to be used in various products like cooling garments and like.
As used herein, a phase change material (PCM) is any material which undergoes a phase
change from solid to liquid form to provide effective cooling of the surface of the skin of the
wearer.
The phase change material essentially comprises following components:
a) A fatty acid like capric acid present in an amount ranging from 20 % to 80%;
6
b) Dodecanol present in an amount ranging from 20% to 80%;
c) A carbon powder present in an amount ranging from 1 % to 2% or combination(s) thereof.
The fatty acid comprises saturated fatty acid selected from a group comprising capric acid,
lauric acid, myristic acid, palmitic acid, stearic acid or combination(s) thereof. The phase
change material is in the form of gelled microcapsules. The shell material of said micro
capsule is made of poly urea formaldehyde. The size of micro capsule ranges from 13 to 97
pm. Figure 1 illustrates DSC curve of phase change material.
The phase change material has following advantageous characteristics which makes the
material appropriate to be used in various cooling system:
Transition temperature of said phase change material ranges from 10 to 25 degree
celsius.
Solidification temperature of said phase change material ranges from 19 to 4
degree celsius.
Latent heat of said phase change material range from 150 to 160kJlkg.
The phase material is thermally stable and is capable of bearing more than 500
heating and cooling cycles. To check the thermal stability of this PCM, 500
heating and cooling cycles were given to material between temperature range
from 20 to 6 0 ' ~an d no significant change in latent heat and phase transformation
temperature was observed (as illustrated in Figure 2)
The product is highly cost effective
The carbon powder in the phase change material is in the form of graphite. The graphite
powder increases the thermal conductivity of material which helps to transfer heat
between PCM and human body.
The phase change material pack (pcm pack) having 110 5g phase change material provides
thermal comfort for about 2 to 2.5 hours at about 42 to 4 8 ' ~te mperature range. This PCM
can also be mixed with water absorbed hydrogel(s) in different weight % ratio depending on
the requirement of comfort duration and comfort level while working or play to provide
comfort human beings working or playing in high heat conditions. The phase change material
may be optionally mixed with a hydrogel so as to increase the efficiency of the phase change
7
material in absorbing heat from the surrounding environment. The hydrogel used in the
present Invention is the conventionally hsed hydrogel(s).
The presently developed PCM have broad melting temperature which absorbs body heat in
broad melting temperature and it can be used for sedentary & mild working conditions. Since
it has broad melting range hence it will provide comfort for more time duration due to small
temperature difference between ambient temperature and PCM melting temperature.
Experimental details:
Different samples having different weight % of capric acid and I-Dodecanol were prepared
and characterized using Differential scanning calorimeter (DSC) to obtain melting
temperature suitable for body cooling and high latent heat. On the basis of these studies
composition 80% capric acid and 20% I -dodecanol was selected for body cooling application
but other compositions may also be used for these applications.
These PCM were microencapsulated using in situ polymerization. The process for the
microencapsulation is following:
The microcapsules were synthesized using in-situ polymerization technique. The
microencapsulation of phase change material is carried out in a 500m1 three-neck roundbottomed
flask equipped with a mechanical stirrer. 3% of polyvinyl alcohol is mixed with
lOOlnl distilled water in the flask at 50°C.
Further, 50 gram of PCM is melted and added to the mixture resulting from the above step.
Now adding 3% of resorcinol to achieve more cross-linking in urea-formaldehyde. The
sample is stirred at 1000 to 1200 rpm for 20 to 30 minutes. Then 30g of urea with 3% by
mass of NH4Cl is added. This emulsion, thus prepared is continuously stirred at the speed of
1000-1200 rpm, maintaining its pH to 3.5 - 4.0 for about 20 to 30 minutes. Next, the
stoichiometric molar amount of 37% formaldehyde is added into the emulsion. The emulsion
is continuously stirred and gradually heated up to 8 0 ' ~fo r 50 to 60 minutes, at pH 3.5 to 4.
The poly urea-formaldehyde encased PCM microcapsules are formed which are cooled to
about 25OC followed by washing with water repeatedly to remove the unreacted urea &
formaldehyde, and thereafter filtering the complete resulting mixture. The filtered
microcapsules are put for 20 to 30 minutes in boiling water to segregate broken
microcapsules. The broken microcapsules float on the water surface and settled perfect
microcapsules of PCM are recovered by filtration. These microcapsules are further dried in
an oven at 100-1 1 O °C forL24hu ntil almost all free formaldehyde and water is removid.
The encapsulation of phase change material in packs helps in preventing the possibility of the
leakage of material during damaging of pack or opening sealing of packs when the material is
present in liquid state. The leakage of the phase change material to body may cause harm to
human skin. Figure 3 and 4 illustrates SEM of microencapsulated PCM.
Cost Effectiveness of the phase change material:
Another aspect of the present Invention is to provide highly economical phase change
material. The currently internationally available PCM cool vests cost about Rs. 10000 to
Rs.15000 while PCM cool vest developed by the present Invention costs only about Rs. 3000
to 4000.
In another aspect of the Invention, there is provided a garment system which comprises
aforesaid phase change material, useful for cooling of a body surface.
In the present embodiment, the invention has been described the garment system with
reference to a cool vest and cool cap, however such description should not be considered as
restricting the scope of the present invention. Further it would be possible for a person skilled
in the art to practice the present invention or use the present phase change material in
preparing other cooling garments, without departing from the scope of the present invention.
In an embodiment of the Invention, there is provided a user's upper torso vest containing
several pockets surrounding the chest and back that holds the PCM packs. The PCM cool vest
contains pockets to hold PCM cool packs, which absorbs excessive heat of body while
working in hot environment and reduces heat stress of body. Body heat carried to the surface
of the skin by the circulatory system is absorbed by the PCM packs. The vest contains
different thickness of insulating layers to control rate of heat transfer from body and
environment. PCMs can absorb, store and release large amounts of energy in the form of
latent heat, over narrowly defined temperature range, during phase transition between two
solid states andlor liquid states. As the body becomes cooler, less heat needs to be expelled.
The phase transition process is completely reversible. Figure 5 (a) illustrates front view of the
cool vest wherein (1) indicates pocket(s) to hold PCM pack, (2) indicates Velcro and (3)
indicates chain. Figure 5 (b) illustrates cool cap having two pockets at front side to hold PCM
cool packs. Figure 7 illustrates front and back view of the phase change material cool vest
wherein (1) indicates front side, (2) indicates chain, (3) indicates pocket pack, (4) indicates
neck, (5) indicates Velcro, (6) indicates back side.
The PCM pouches are used in sufficient numbers to extend over a large area of the garment.
It is desirable not to include any pouches at areas required to be flexible, such as elbow
portions in a jacket, although suitably sized pouches may be arranged around such areas. It is
also desirable to leave some gap between adjacent pouches to allow the garment to be
breathable (as noted the textile used for the garment is preferably breathable). The pouches
do exhibit a degree of flexibility and can be deformed (in use) to provide increased comfort.
Fitting of the pouches to body contours in this way can also improve the efficiency of thermal
transfer. The arrangement of pouches in an article of clothing is preferably designed by
reference to infrared thermal imaging of the body of the intended wearer during pre-event,
intra-event and/or post-event (cool down) periods, depending upon the intended use of the
clothing. The PCM pouches may be inserted into pockets within the garment and sealed
therein, removably for example by fasteners such as zips and Velcro. Figure 6 illustrates
pockets in the PCM cool vest. Figure 8 illustrates construction of pocket to hold PCM packs
wherein (1) indicates Body side while (2) indicates Ambient side, (3) shows poly urethane
foam of 5 mm thickness, (4) indicates poly urethane foam of 20mm thickness, (5) shows
cotton fabric lining, (6) indicates army color cotton fabric while (7) shows space for PCM
pack.
Further customization(s) were carried out with different foam thickness used in vest towards
body side and ambient side. The details of calculations are given in following table. It is
observed that the heat transfer between body, PCM pack and environment takes place by
statistic conduction and so the radiation and convection factors were not taken into account.
The body temperature was taken to be about 3 7 ' ~ while ambient temperature was taken
constant to about 50'~.
hlP of
PCM
Latent
heat of
PChl
Insulation
thickness
bet\+ een
PCRl and
bo&
(mm)
Heat flux
between
PCRl and
body
(\+/m2) Q,
Insulation
thickness
beh een
PChl and
environment
(mm) X2
Heat flux
from
environm
ent to
PChf
(wlm2) Q2
Combination
of insulation
thickness
towards body
and
environment
Total
heatlarea
to PChl
in two
hours
(RIJlm2)
\\'eight
of PCM
to
absorb
heat
(glcm2)
Thickness
of PCRl
required
for 2 hrs
holding
time (em)
160 10 36 20 52.5
Table 1
I
I On the basis of above calculations, the foam thickness in pocket of vest towards body was
taken to be in the range of 4 to 6mm and particularly 5 mm, while towards ambient side it
was taken to be in the range of I Omm to 20mm.
The following description is of exemplary embodiments only and is not intended to limit the
scope, applicability or configuration of the invention in any way. Rather, the following
description provides a convenient illustration for implementing exemplary embodiments of
the invention. Various changes to the described embodiments may be made in the function
and arrangement of the elements described without departing from the scope of the invention.
In an embodiment of the present invention, fatty acid in the phase change material is selected
from capric acid, lauric acid, palmitic acid, stearic acid.
In another embodiment of the present invention, phase change material is in the form of
gelled microcapsules.
In another embodiment of the present invention, the shell material of said micro capsule is
made of poly urea formaldehyde.
In another embodiment of the present invention, the cooling garment may take the form of a
jacket, trousers, shorts, hood, hat, gloves, scarf etc., depending upon the intended field of use.
In another embodiment of the present invention, the PCM pouches may be inserted into
pockets within the garment and sealed therein, either permanently for example by stitching or
removably for example by fasteners such as zips and velcro.
In another embodiment of the present invention, the pack(s) may be made in different shapes
(e.g., rectangular, circular, cylindrical, etc) as a matter of choice and for special applications.
In another embodiment of the present Invention, the phase change material is mixed with a
hydrogel.
The invention will now be explained with the help of following examples. However, the
scope of the invention should not be limited to these examples as the person skilled in the art
can easily vary the proportion of the ingredients and combinations.
Example 1:
The PCM cool vest was designed to provide controlled heat transfer rate (70 to 160 w/m2)
between body and PCM packs. 12 pockets (6 at front and 6 at back side) in vest have been
provided to hold PCM packs. 5 mm thick polyurethane foam (PUF) has been optimized for
pockets towards body for ideal heat flow rate from body to PCM pack to keep body in
comfort zone. To reduce heat flow between environment and PCM pack, 20 mm thick PUF
has been used as lining in pockets towards ambient side. The weight and thickness of PCM
pack was optimized to provide thermal comfort for about 2 to 2.5 hours in high temperature
environment of about 40 to 48 degree celsius. The weight of the PCM in vest has been
equally distributed at heat sensitive locations to absorb excessive heat of body. 6 strips of
Velcro (3 on each side) have been provided in vest to tighten the vest as per individual's size
and comfort. The micro encapsulated PCM used in PCM cool packs have melting
temperature ranging from 10 to 25 degree Celsius. PCM cool vest provides cooling at 70 to
160 w/m2 heat flux to the human body which is suitable for sedentary and mild working
conditions.
PCM cool packs have to be solidified in deep freezer before utilizing PCM cool vest. At the
time of use of PCM cool vest, PCM packs have to be inserted in the pockets provided in the
vest.PCM cool packs absorb large amount of heat in the form of latent heat of PCM during
phase change (solid to liquid) and maintains temperature in the range of about 17 to 28
degree Celsius in the vicinity of the body.
Salient features of PCM cool vest:
Material of construction
Number of pockets
Construction of Pocket
Number of Velcros
Size of PCM pack
Weight of PCM pack
Weight
Cotton Fabric
12 in vest and 02 in cap
20 mm thick PUF insulation layer towards ambient
and 5 mm PUF insulation towards human body
06 (three on each side)
About I Ocm (W) X12cm (L) X 2cm (thick)
0.100 to 0.1 10 kg
Vest: about 2 kg, Cap: about 0.3 Kg
Example 2:
Recharging of PCM packs
Comfort duration
The PCM cool cap was designed to provide controlled heat transfer rate (70 to 160 w/m2). 02
pockets (at front side) in cap have been provided to hold PCM packs. 10 mm thick
polyurethane foam (PUF) has been optimized for pockets towards body for ideal heat flow
rate from body to PCM pack to keep body in comfort zone. The weight of the PCM in vest
and cap has been equally distributed at heat sensitive locations to absorb excessive heat of
body.
2-3 hours in deep freezer of normal refrigerator
about 2.5 hrs which can be further increased by
Inserting fresh recharge PCM packs or colorable
PCM cool packs
Example 3:
The phase change material composition is prepared by mixing capric acid with 1-dodecanol.
The capric acid is present in an amount of 40% by weight of the total composition while 1-
Dodecanol is to mixed in an amount of 60% by weight of the total composition. The DSC
curve of phase change material (PCM) produced by this experiment is shown in Figure 9.
Example 4:
The phase change material composition is prepared by mixing capric acid with 1 -dodecanol.
The capric acid is present in an amount of 70% by weight of the total composition while 1-
dodecanol is to mixed in an amount of 30% by weight of the total composition. The DSC
curve of phase change material (PCM) produced by this experiment is shown in Figure 10.

WE CLAIM:
1. A phase change material comprising a fatty acid present in an amount ranging from
20% to SO%, Dodecanol present in an amount ranging from 20% to SO%, a carbon
powder present in an amount ranging from 1 % to 2% or combination(s) thereof.
2. The phase change material as claimed in claim 1 , wherein the transition temperature
of said phase change material ranges from 10 to 25 degree celsius.
3. The phase change material as claimed in claim 1, wherein the solidification
temperature of said phase change material ranges from 19 to 4 degree celsius.
4. The phase change material as claimed in claim 1, wherein the latent heat of said phase
change material range from 150 to 160kJlkg.
5. The phase change material as claimed in claim 1, wherein said material is thermally
stable and is capable of bearing to more than 500 heating and cooling cycles.
6. The phase change material as claimed in claim 1, wherein said fatty acid comprises
saturated fatty acid selected from a group comprising capric acid, lauric acid, myristic
acid, palmitic acid, stearic acid or combination(s) thereof.
7. The phase change material as claimed in claim 1, wherein said carbon powder is
graphite.
8. The phase change material as claimed in claim 1, wherein said phase change material
is in the form of gelled microcapsules.
9. The phase change material as claimed in claim 1, wherein said phase change is
optionally mixed with a hydrogel.
10. The phase change material as claimed in claim 8, wherein the shell material of said
micro capsule is made of poly urea formaldehyde.
11. The phase change material as claimed in claim 8, wherein the size of micro capsule
ranges from 13 to 97 pm.
12. The phase change material as claimed in claim 1, wherein said phase change material
provides thermal comfort for about 2 to 2.5 hours at about 40 to 48' C temperature
range.
13. A thermal garment system comprising a phase change material as claimed in claim(s)
1 to 12.
14. The thermal garment system as claimed in claim 13, wherein said garment comprising
a vest having front (1) and back panels (6) for substantially covering and conforming
to the chest and back of said user's torso, said front (1) and back panels (6) attached to
each other from top while defining an opening through which said user's head extends
(4), when worn, plurality of straps (5) extending from said back side adapted to be
tightened to said front side, a closing means (3) present in said front side. a plurality
of pocket(s) integrally attached to at least one of said panel(s), each of said pockets
having an open end and a closed end defining an inner cavity adapted to receive and
support at least one phase change material pack therein.
15. The thermal garment system as claimed in claim 13, wherein said pocket comprises a
body side surface (1) and an ambient side surface (2) creating an interstitial space (7)
for locating a phase change material pack therein, said surface(s) comprises atleast a
poly urethane foam (4,5), atleast a cotton fabric lining (6,7).
16. The thermal garment system as claimed in claim 13, wherein the thickness of said
poly urethane foam present towards body surface ranges from 4mm to 6mm.
17. The thermal garment system as claimed in claim 13, wherein the thickness of said
poly urethane foam present towards body surface ranges from I Olnm to 201nm.
18. The thermal garment system as claimed in claim 13, wherein said garment enables
controlled heat transfer rate in the range of 70 to 160 w/m2.
Dated this 1 3th day of September 201 3
Suvarna Pandey
Of S. Majumdar & Co.
(Applicant's Agent)