FIELD OF THE INVENTION
The present invention relates in the field of fire safety products. More particularly, the
present invention provides a fire retardant felt of good strength. Fire retardant felt is
, made from viscose rayon fiber with needle punch. Felt is fire retardant and in
carbonized state it shows non conductor property.,
BACKGROUND OF THE INVENTION
A wide variety of different fibers and fibrous blends have been used in the manufacture
of fire and heat resistant yarns and fabrics but there is a continuous need of improved
yarn qualities and fabrics. A fire blanket must possess properties of fire retardance,
tensile strength, heat resistance, moisture absorption property.
Lots of products from fire retardant felts are produced for example, Fire retardant
curtains, fire retardant blankets, fire retardant gloves. welding blankets and many other
products are available now.
In a normal process, a fire retardant and heat resistant yarn is manufactured by * m- + incorporating 99.9% by weight oxidized polyacrylonitrile fibers and 0.1 % p-aramid fibers.
The yarn is then knitted or woven into a variety of fire retardant and heat resistant
k s fabrics. The resulting fabrics have extremely high fire retardance and heat resistance
properties. Such fabrics are better suited for uses that not have high requirements of *- 7 tensile strength and abrasion resistance, such as fire walls or heat resistance layers
surrounded by more durable fabrics.
Any of the foregoing yarns and fabrics is modified by replacing some or all of the pbo
c3 aramid with one or more of the following types of strengthening fibers such as I
polybenzimidazole fibers, rnodacrilic fibers, m-aramid fibers, polyvinyl halide fibers, wool I CV w fibers, fire resistant polyesters fibers, fire resistant nylon fibers, fire resistant rayon
fibers, cotton fibers, Nomex fibers, Proban fibers, Basofil fibers, and Panox fibers.
Various studies have been carried out in the instant state of art and numerous techniques
have been done for the production of Fire Retardant felt as shown below: '
The subject matter of US patent 4532278 A provides a com bination of compositions and
a method for rendering polyolefin materials flame retardant without loss of the desirable
textile properties such as water-white color and hand.
US 4365655 A teaches about a flame-retardant fabric by intetweaving a warp
comprised substantially exclusively of a conventional staple fiber with a weft comprised
substantially exclusively of a flame-retardant matrix fiber.
A discloses about a heat resistant woven fabric with an optional aluminized
backing, the fabric being made from yarns having a core of flame and high heat
resistant non-melting heat stabilized polyacrylonitrile fibers covered by a layer of aramid
fibers or other heat resisting fibers with or without blending 'with other fibers.
A provide a highly lustrous, flame retardant acrylic fiber of low apparent
soiling tendencies, containing a acrylonitrile polymer containing acrylonitrile, an amount
a I of a halogen-containing vinyl monomer sufficient to impart flame retardancy to said
fiber, and any balance of a halogen-free monomer.
The subject matter of US6021523 A pertains to a stain, heat and abrasion resistant
LL woven glove prepared by twisting KEVIARB with a high temperature resistant polyester G
7 or oxidized polyacrylonitrile using substantially conventional textile fabric forming

technotogy such as knitting.
A provide an abrasion and fire resistant permanent' press fabric formed
from yarns comprising an intimate blend of oxidized polyacrylonitrile with at least two
other synthetic fibers which is fire resistance and still has good hand.
The present invention tends to overcame above limitations and applicant has developed
a new method of preparing fire retardant felt.
OBJECT OF THE INVENTION
It is the principal object of the invention to provide a fire retardant felt.
It is another object of this invention to provide fire retardant felt made from viscose
rayon with needle punch.
It is still another object of this invention to provide a felt of good strength and is resistant
to high temperatures, abrasion resistance and exhibits bad conductor of electricity in
carbonized state.
It is still further object of this invention to provide fire retardant felt which are
commercially useful in a broad range of applications, and yet safe and practical in
operation.
It is still another object of this invention that felt can be used in broad range such as Fire
retardant blankets, welding blanket, fire retardant curtains, Gloves, and kitchen cloth
etc.
Other objects and advantageous features of the invention will be apparent from the
description and claims
SUMMARY OF THE INVENTION
The various embodiments of the present invention provide an improved fire and flame
retardant felts made from viscose rayon and other fibrous blends that are able to satisfy
a wider range of performance criteria compared to conventional fire retardant fabrics
and other fibrous blends.
According to the embodiment of the present invention, the yarns, fabrics, felts and other
fibrous blends used in the present invention include viscose rayon with needle punch.
The fire retardant felt is prepared by a process using viscose rayon with needle punch,
the said process comprises of first taking the raw material i.e. viscose rayon, pretreating
it with chemicals and than carbonizing the obtained mixture in furnace at 400'~ and
finally felt is activated at 800'~ ,whole process is increasing temperature gradually in
presence of nitrogen and carbon dioxide gases.
In one embodiment of the present invention, fire retardant felt can be used either in
carbonized form or in activated form.
In other embodiment of the present invention, fire retardant felts and other products
made there from shows improved .resistance to heat transfer, besides having adequate
strength, including tensile strength and abrasion resistance. In one embodiment of the present invention, fire retardant blanket can be used in fire
emergencies, like kitchen cloth for small 'kitchen fires, welding blankets and blankets
csaafne tbye, used in industries for small fires and fire retardant curtains can atso be in fire
In one embodiment of the present invention, blanket made from felt can be used in
LL molten splash application
In yet another embodiment of the present invention, products not limited to blanket,
gloves, kitchen cloth, welding blanket and curtains made from carbonized felt possess
non conductivity property and can be used for In another embodiment of the present invention, products not limited to blanket,
CV w mattresses, kitchen cloth, welding blanket and curtains made from activated felt can be
used for absorption of pollutant in hospitals and in many other application$ where
pollutants can be removed with absorption phenomenon.
The foregoing has outlined, in general, the various aspects of the invention and is to
serve as an aid to better understanding-the more complete detailed description which is
to follow. In reference to such, there is to be a clear understanding that the present
invention is not limited to the method or application of use described and illustrated
herein. It is intended that any other advantages and objects of the present invention that
become apparent or obvious from the detailed description or illustrations contained
herein are within the scope of the present invention.
DETAILED DESCRIPTION OF THE INVE'NTfON
The invention will now be described in detail with reference to a few preferred
embodiments. In the following description, numerous specific details are set forth in
order to provide a thorough understanding of the invention. However, it will be apparent
to one skiiled in the art that the invention may be practiced without some or all of these
specific details. In other instances, well-known features andlor process steps have not
been described in detail in order to not Y nnecessarily obscure the invention.
The various embodiments of the present invention provide an improved fire and flame
retardant felts made fiom viscose rayon and other fibrous blends that are able to satisfy
a wider range of performance criteria compared to conventional fire retardant fabrics
and other fibrous blends.
In the present invention, fire retardant felt is made from viscose rayon with needle
punch.
In the preferred embodiment of the presenf invention, the fire retardant felt is prepared
by a process wherein the said process comprises of following steps:
Viscose rayon is used as a Raw material .
Pretreatment of fabric is done with chemical method by using phosphoric acid.
After pretreatment, the carbonization at 400'~ to 450% temperature is done in
furnace
Finally, activation of felt occurs from 500'~ upto 800'~ temperature .
Gases like COz or Nitrogen are passed for cooling to avoid over heating or .
burning of carbon felt.
In one embodiment of the present invention, fire retardant felt can be used either in
carbonized form or in activated form.
In one aspect of the present invention, felt that is produced in the furnace possess fire
retardant property and in carbonized state it is non conductor of electriciv and in
activated form it is good conductor of electricity.
In one aspect of the present invention, fire retardant felt prepared from viscose.rayon
shows better properties than from other material such as it is bad conductor of electricity
in carbonized state, felt can also be used as insulation material in electronic industry.
Properties of Viscose Rayon
The various propertiesf characteristics of viscose rayon such as moisture absorption,
elasticity, tensile strength, density and other chemical properties are studied and
determined using various techniques as described below:
Moisture Absorption
Viscose rayon absorbs more moisture than cotton. Moisture Content of Cotton is 6% at
70' F and 65% RH, and for Viscose Rayon it is 13% under the same conditions
Elasticity
The elasticity of Viscose Rayon is less than 2-3% which is very iinp~rtantin handling
viscose yarns during weaving, stentering etc when sudden tensions are applied.
Tensile Strength
The Tensile Strength of the fibre is less when the fibre is wet than when dry. Ordinary
Viscose rayon has 15-30% elongation at break, while high tenacity rayon has only 9-
17% elongation at break
Density
The density of Viscose rayon is 1.53 g/cc, Rayon filaments .are available in three I densities: 1.5, 3.0 and 4.5
Exposure to Sunlight
Viscose Rayon loses its strength at 300' F and begins to decompose at 350-400' F.
Prolonged exposure to sunlight also weakens the fibre due to moisture and ultraviolet
light of the sunlight.
Chemical properties
Viscose rayon reacts faster than. cotton with chemicals as its amorphous region is
CV w higher and also it consists of cellulose of lower DP than cotton cellulose.
Acids like H2SO4 , HCI breaks the cellulose to hydrocellulose. Oxidizing agents like
Na(OC1)2, Bleaching powder, K2Cr2O7K, Mn04-f orm oxycellulose.
Cold acid solutions for a short time do not attack viscose rayon.
Action of solvent
Textile solvents can be used on Viscose rayon without any deteriorating effect. Viscose
rayon dissolves in cupramrnonium hydroxide solution.
Effect of Iron
Viscose rayon yarns weaken when it is contacted with iron as ferrous hydroxide.
Therefore staining, marking or touching of rayon to iron or iron surface should be
avoided.

Action of Microorganisms
Microorganisms (moulds, mildew, fungus, bacteria) affect the colour, strength, dyeing
properties and luster of rayon. Clean and dry viscose rayon is rarely attacked by moulds
and mildew.
In other embodiment of the present invention, fire retardant felts and other products 7 made there from viscose rayon shows improved resistance to heat transfer, besides
having adequate strength, including tensile strength and abrasion resistance.
In one embodiment of the present invention, blanket made from felt can be used in
molten splash application, fire retardant blanket can be used in fire emergencies, like
kitchen cloth for small kitchen fires, welding blankets and blankets can be used in
CV w industries for small fires and fire retardant curtains can also be in fire safety.
In yet another embodiment of the present invention, products not limited to blanket,
gloves, kitchen cloth, welding blanket and curtains made from carbonized felt possess
non conductivity property and can be used for protection from electricity.
In another embodiment of the present invention, products not limited to blanket,
mattresses, kitchen cloth, welding blanket and curtains made from activated felt can be
used for absorption of pollutant in hospitals and in many other applications where
pollutants can be removed with absorption phenomenon,
CHARACTERlZATION STUDIES
The various characteristics of felt so prepared from viscose rayon are analyzed and
determined using characterization techniques as described below:
Tests
NFPA 7101- This standard establishes test methods to assess the propagation of flame
of various textiles and films under specified fire test conditions.
For felt NFPA test is positive.
Oxygen Index
It is the minimum oxygen concentration to support candle like combustion of materials.
The test sample is positioned vertically in a glass chimney, and an oxygenlnitrogen
environment is established with a flow from the bottom of the chimney. The top edge of
the test sample is ignited, and the oxygen concentration in the flow is decreased until
the flame is no longer supported.
Oxygen Index of felt is 52.3
Vertical Inflammability test
The sample is suspended veitically so that it can be ignited at the bottom. After ignition,
the ignition source (usually a bunsen burner) is withdrawn and the length of burn of the
sample in a set period of time (10 seconds) is measured. If the sample does not burn for ,
the entire time, the time to extinguish is noted.
Materials which burn while the ignition source is in contact but go out quickly when it is
removed are termed self-extinguishing. This test is most useful in measuring the
burning characteristics of similar materials. Dripping of the resin should be noted.
Felt sample meets the requirement, weight loss is nil.
Ash content
An Ash test involves taking a known amount of sample, placing the weighed sample into
a dried I pre-weighed porcelain crucible, burning away the polymer in an air atmosphere
at temperatures above 500°C, and weighing the crucible after it is has been cooled to
I room temperature in a desiccator. Ash residue remaining in the crucible is considered
filler unless the residue is less than 1%. Residues of less than 1% are typically the
cu result of additives that did not burn off.
Ash content is 0.47%
Tensile strength
It is a measure of the ability of material to resist a force that tends to pull it apart. It is
expressed as the minimum tensile stress (force per unit area) needed to split the material apart.
Tensile strength of fiber of felt is-
Lengthwise-1 0.00N
Widthwise-1 2,70N
Diameter of fiber-l 1.47Micron
Bulk density
It is defined as the mass of many particles of the material divided by the total volume
they occupy.
Bulk density of felt is 0.16glcm3.
Products made from fire retardant felt
Fire retardant blankets, welding blanket, fire retardant curtains, Gloves and kitchen cloth
can be made from felt with fire retardant felt.
The present invention has been described in an illustrative manner, and it is to be
understood that the terminology used is intended to be in the nature of description
rather than of limitation. Many modifications and variations of the present invention
are possible in light of the above teachings. It is also to be understood that the
following claims are intended to cover all of the generic and specific features of the
embodiments described herein and all the statements of the scope of the
embodiments which as a matter of language might be said to fall there between.
Therefore, it is to be understood that within the scope of the appended claims, the
invention may be practiced otherwise than as specificilly described.
ADVANTAGES OF THE INVENTION
As desired above, the present invention is advantageous due to the following
reasons:
Felt prepared in furnace possess fire retardant property and in carbonized
state it is non conductor of electricity and in activated form it is good conductor
of electricity.
Fire retardant blankets so prepared, can be used in places where safety from
electricity is required as safety blankets.

We claim:
1. A fire retardant felt and a process of preparing felt from viscose rayon and other
fibrous bends with needle punch, the said process comprising the steps of:
Using Viscose rayon as a Raw material
Pretreatment is done with chemical method
a After pretreatment, the carbonization at 400% temperature is done in
furnace
Finally, activation of felt occurs at 800% temperature
2. Fire retardant felt prepared from viscose rayon as claimed in claiml, wherein
said felt possess better properties as viscose rayon absorbs more moisture than
cotton and reacts faster with chemicals as compared to cotton.
3. Felt as claimed in claim 1, wherein said felt possess fire retardant property and in
carbonized state it is non conductor of electricity and in activated form it is good
conductor of electricity.
4. Fire retardant felt as claimed in claim 1, wherein said felt can be used as Fire
retardant blankets, welding blanket, fire retardant curtains, Gloves and kitchen
cloth etc.
5. Fire retardant felt as claimed in claim 7 , wherein said fire retardant felts and other
products made there from viscose rayan shows improved resistance to heat
transfer, besides having adequate strength, including tensile strength and
a brasion resistance.
6
00
c3 6. Fire retardant felt as,claimed in claim 1, wherein products such as blanket made 2
OI
cu 'from felt can be used in molten splash application, ffre'retardant blanket can be
used in fire emergencies, kitchen cloth for small kitchen fires, welding blankets
and blankets can be used in industrie* for small fires and fire retardant curtains
can also be used in fire safety,
7. Fire retardant felt as claimed in claim i, wherein products not limited to blanket,
mattresses, kitchen cloth, welding 'blanket and curtains made from activated felt
can be used for absorption of pollutant in hospitals and in many other
applications where pollutants can be removed with absorption phenomenon.
8. Fire retardant felt as claimed in claim ?, wherein products not limited to blanket,
gloves, kitchen cloth, welding blanket and curtains made from carbonized felt
possess non conductivity property and can be used for protection from electricity. '
9. Fire retardant felt as claimed in claim 7 , wherein said felt is characterized for
. its properties using techniques such as NFPA 707, oxygen index, ash content,
vertical inflammability test, tensile strength, Bulk density etc.