FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003 COMPLETE SPECIFICATION
(See Section 10; Rule 13)
1. TITLE OF THE INVENTION:
"IR Treated Filament wound Composite Pressure vessels."
2. APPLICANT:
(a) NAME: GLOBAL COMPOSITES & STRUCTURALS LIMITED.
(b) NATIONALITY: AN INDIAN COMPANY INCORPORATED UNDER
THE COMPANIES ACT, 1956.


(c) ADDRESS: VILLAGE NICHOLE, POST KHANAVILI,
TAL: WADA, PIN-421 303, DIST : THANE,, MAHARASHTRA, INDIA.
The following specification describes the nature of the invention and the manner in which it is to be performed: -

IR Treated Filament wound Composite Pressure vessels
3. PREAMBLE TO THE DESCRIPTION
Field of Invention
The present invention relates to IR treated filament wound composite pressure vessels.
Background of the Invention & the Related Art
The basic process of filament wound pressure vessels includes the continuous glass fiber strands (end roving) being coated with epoxy rein and further this coated glass fiber then being wound on a mandrel liner, at a predetermined angle & winding thickness. This process yields the composite vessels a high strength when the resin element is cured.
The basic needs of adopting filament winding process for composite pressure vessels are as follows:
1) There are no seam joints either horizontally or vertically in the filament wound processed composite pressure vessels.
2) The pressure vessel has cylindrical shell body with bottom dome and top dome ends, but without the seam joints. The top portion opens in to a-flanged adapter which has provision to get fitted with pressure relief valve/vacuum breaker. Normally such pressure vessels in metals would have seam joints at shell and
domes or in the shell itself. These joints are susceptible to leaks under high pressure and causes potential danger to the operating persons. Hence, when the composite pressure vessels were devised, the filament winding process was an automatic choice.

' 3) The weight to strength ratio is very high. The glass fiber composition in a pressure vessel ranges from 65% to 75% which gives the product light weight but a high strength
4. DESCRIPTION OF THE INVENTION
OBJECTS OF THE INVENTION:
. The basic purpose of invention is to treat the filament wound epoxy bonded pressure vessel with IR coils. This process helps the resin to attain proper curing without
r dripping or sagging. Unlike the other heating medium, the IR heating does not require air. When IR radiation is absorbed by an object, heat is generated internally in the object as IR causes the atom of the object to vibrate, raising its temperature. The epoxy resin thus treated with IR, exhibits mechanical properties akin to UV treatment of Epoxy resin for which there are established results which are tabulated as follows:
Thermo setting reaction with hardener
The resins contain at least one heat activated curing agent. The curing agent may be an amine-containing compound from the group consisting of dicyandiamide boron trifluoride:amine, complexes, boron trichIoride:amine complexes, latent amine curatives, tertiary amines, aromatic polyamines and imidazoles These amine curing resins are created by mixing an epoxy resin component comprising at least one a polyepoxide, a photo initiator and peroxide, with a curing component comprising an amine-containing heat activated curing agent. Separately, the two components epoxy component (and curing component) of the amine curing resins have essentially unlimited shelf life. When mixed, the compositions can retain a usable viscosity (pot-life) i.e., less than about 2000 centipoises (cps), for a minimum of about 1/2 and preferably about 1 to VA hours at temperatures ranging from about ambient ' temperature to about 60° C to 80° C. The amine curing'resin compositions have a Tg in the range of about 110° C. to about 160° C, when frilly cured. The amine curing

resins of the present invention have an epoxy component present in an amount ranging ' from about 60 wt % to about 85 wt %, and preferably, about 63 wt % to about 75 wt %; a polyolefinic component present in an amount ranging from about 5 wt % to about 30 wt %, and preferably from about 10 wt % to about 20 wt % of the composition. Most preferably the polyolefin component is present at about 15 wt % of the composition. The amine-containing heat activated curing agent is generally present in an amount ranging from about 2 wt % to about 10 wt %, and preferably from about 3 wt % to about 6 wt %. Most preferably the heat activated curing agent is present in an amount of about 5.5 wt %. The photo initiator is generally present in an . amount ranging from about 1 wt % to about 10 wt %, and most preferably from about 2 wt % to about 5 wt %. The free radical initiator (organic peroxide) is present in an . amount ranging from about 0.2 wt % to about 2 wt %, preferably from about 0.5 wt % to about 1.5 wt %. Miscellaneous additives such as wetting and defoaming .agents can be added collectively in amounts of about 0.5 to about 1% by weight of the composition, added as part of the resin component. Optionally, fire retardant materials such as phosphorous-containing compounds may be present in amounts of about 2% to about 10%, and preferably about 3% to about 5% by weight of the composition.
Ultraviolet Light Absorber for Epoxy Resins
' UV ABSORBER specifically designed for the protection of epoxy resins against the damage from UV light radiation. UV ABSORBER is characterized by its good solvent solubility, better resin compatibility and less volatility. UV ABSQRBER provides a degree of stabilization that is significantly better than those of other commercialized UV absorbers based on benzotriazole or benzophenone.
Composition:
Active Ingredients:
UV absorber based on dialkylaminobenzoic ester Hinder Amine Light Stabilizer

Specification
Appearance
Assay
Freezing point Volatiles Clarity in toluene
Light yellow liquid
98.0 % (Active ingredient)
10°Cmax.
1.0%
Clear solution (5g/100ml)
Application: UV additive is most suitable for the protection of polymers due to its excellent solubility in resin and its "non-yellowing property during baking stage. Therefore, is exclusivity designed for:
Epoxy resin.
Epoxy aery late.
After each 200 hrs Exposure:

Heat resist F 0 F X
UV resist X .F O X
O: Good, F: Fair, X: Yellowing
Description of the Invention:
The purpose:
The main purpose of the invention was to treat the epoxy wound pressure vessel with IR and the coils to impart a consistent heat without inducing high shrinkage properties and generating internal stresses in the curing resin and the composite laminate body.
IR Curing Chamber UTILITY OF THE IR OVEN:
This IR Oven basically functions on the following principles.

1. . pesigned Heating Temperature of the IR( max up to 60 deg centigrade.
2. pesigned Duration of the time (maximum up to 1-5 hr)
3. Pesigned Range of IR heaters wattage capacity is 1 kW for heating element whose OL length 1200 mm .Total Number ofHeaters in the chamber is 6.
4. Designed wave length of the short wave IR is 0.7 microns.
5. pesigned Wattage of IR required 1 ..00/hr. of the surface area to be treated.
■ 6. ' Reflectors at side walls and bottom, which reflect the heat back on the product.
The ceramic Layers back up is given to the heat reflector body so that there is no heat loss. The Reflectors also helps the product to have an external coat of epoxy resin as the dripping resin is not allowed to drip but allowed to be coated on the external surface.
7. pesigned RPM for the mandrel Rotation is maximum up to 50.to 30 depending
upon the tank's dimensions.
8. , Heating, temperature, time and RPM are controlled by external control panel.
. 9. The Pressure vessel is kept on a horizontal position (in an enclosed chamber)
10. The IR treating helps to add service life of the product which, the overall dimension of the IR chamber is as follows:
a) Length IS to IS 2238 mm.

b) Width is 955 mm.
c) Height is 858 mm.
d) Centre distance of the SS shaft, which carries Mandrel, is 1950 mm adjustable clamp length on either side is 120 mm bearing length is 50 mm. (bearing is SKF with centre dia of 50 mm)
the mandrel can be loaded in to the chamber from sideways and locked in to a groove. The oven is connected with a DC Motor 1 hp, capacity 318 kW. The RPM of the Motor to rotate the Shaft is 25. These dimensions are for this particular pressure vessels range from 10" dia to 24" dia. The same IR range of chamber can be done for pressure tubes up to ten mtr length and 8 inch diameter.
A molecule" of diglycidyl ether of bisphenol A.
A molecule of diethylene triamine (DETA) a curing agent.
The Cure Chemistry Basics:



Epoxy Resin Chemistry Viscosity
• Viscosity of the resins is the important parameter in processing the resin for cure.
• .Aromatic based epoxy resins with three or more epoxy groups per molecule are semi solids or solids at room temperature. Blending of these resins with aliphatic based diepoxy resins results in viscous liquids at room temperature.

• Viscosity of the resin increases in proportion to the molecular weight of the species present.
• Viscosity of resin decreases with increase in temperature in the absence of any curing reaction.
Curing Agents for Epoxy Resins
• Many curing agents are commercially available.
• These curing agents can be broadly classified into three categories:
o Amine group curing agents."
o Acid anhydride group curing agents.
o Acid curing agents. .
o Diethylene triamine (DETA), triethylene tetramme (TETA), Tetra
ethylene pentamine (TEPA), and Dicyandiamide (DICY) are the
commercially used curing agents.
Aliphatic Amine Hardeners:


• Aromatic Amine Curing Agents
• Overtake all amine type curing agents
• Some of the more commonly used aromatic diamines are m-phenylene diamine (MPDA), 4,4'-methylene dianiline (MDA), and diamine diphenyl sulfone (DDS)
*
• Any one of these amines can be used as a curing agent
• Generally, mixtures of these amines are employed in commercial practice
• These amines react very slowly at room temperature and need heating for fast and complete cure Curing of Epoxy Resins
Curing of Epoxy Resins:
• Epoxy resins are available in a wide range of molecular structures, suitable for curing with a large variety of different curing agents to make products with required properties.

• During the curing of these resins, physical and chemical changes are taking
place.
• The physical changes occurring due to chemical reaction are
. • Viscosity
• Temperature due to exothermic nature of curing
• Gel effect.


Exotherm.
• The exotherm occurs before the gelation, in the case of curing of DGEBA with aliphatic amines.
• Initially all the primary amine hydrogens are reacted with epoxy groups to form long chains.
• The primary amine groups produce secondary amine groups on reaction with epoxy group.
,• Secondary amine groups can react with epoxy at high temperature only.
• Secondary amine reaction brings cross-linking between chains at slow rate and
cause gelation.
Viscosity During Cure:
. • Initially the viscosity of resin decreases
• The viscosity reaches to a minimum level at the peak exotherm, and wherefrom it increases rapidly with cross-linking of chains
• After glassy state practically no .reaction takes place at that temperature
• • Post-curing at higher temperature has to be done
■• Post-curing increases the heat distortion temperature of the cured product
Gelation:
• When all the chains have at least one cross-link, the gelation occurs. ■
• The chains cannot be mobile.
. • All the processing operations should be completed before the onset of solidification.
• It is necessary to remove voids before the onset of solidification.
• Generally, a dwell is employed at minimum viscosity level to allow the bubbles ■ come to the surface.
PART A
Epoxy Resin 75% -75% 77% 80%

Hardener 25% 25% 23%
DEFOAMING AGENT* 0.5 0.5 0.5 0.5
WETTING AGENT* 0.1 0.1 0.1 0.1
. VISCOSITY (cps)
0 hours at 25 deg C) 730 860 1100 950
25 mins (at 40deg C) 1100 1250 1650 1400
40 mins (at 50 deg C) 1300 1400 1800 1600
60 mins (at 60 deg C) 100 120 75 120
90 mins (at 60 deg C) NC NC solid PC
120 mins (at 60 deg C) solid NC PC
DRIP ON HOOP WIND

GLASS FIBER NO Yes NO yes
Type
of
Resin Type of hardener Hardener 2 Ratio of Resin
:hardener %Wetting of roving Curing
Time
duration Observation for curing
Epoxy
Resin
X Hardener 1 Nil 100:32 or 75:25 100% Cured in 120 mins. At 60 deg C. Eruption on the outer surface of the vessel.
Epoxy
Resin
X Hardener 1 Nil 100:32 or 75:25 60% Not cured in 2 hrs. Eruptions after curing. On outer surface.
Epoxy
Resin
X Hardener 1 Hardener 2 77:18.5 :4.5 60% Cured in
100
minutes No
Eruptions After curing on outer surface. 3rd sample OK.
Epoxy
Resin
X Hardener 1 Hardener 2 80:12.32 :7.2 60% 90%cured in 50 minutes. Eruptions After curing on outer surface.

. PROCESS: TECHNICAL DESCRIPTION:
The filament winding processes used with the present compositions are for the most part continuous processes. Typically, the resin composition is housed in an open vessel beneath a rotating roller. The rotating rolfer is partially submerged in the resin so as to coat the roller as it rotates. Fiber is drawn from a spool and directed through the resin and into contact with the roller surface, whereby the fiber is coated with resin as it passes and may be further cured, subsequent to winding; the formed article is placed in an IR oven at an appropriate cure temperature. In general, the compositions or the present invention can substantially reach a fully cured state by heat curing at about 60° C. to about 80° C. for about 1 to 1.5 hour. The time and temperature of the heat cure may be varied to reach particular desired results.
The Epoxy resins which are used in FW must have properties like low initial Viscosity and Extended pot life.
Bl) The low initial viscosity is required for proper uniform deposit'of epoxy resins on continuous filament so as to have uniform properties in the final product, otherwise the product would have localized stress, discontinuities in the " product and affect the dimensional tolerance specifications and post curing of the resin itself. In addition the tensional forces on the impregnated filaments will significantly increase to- such an extent that the filament becomes highly susceptible to snapping.
B2) Extended Pot-life is required because winding operation's processing be in the order of 30 TO 60 minutes. Hence the resin bath must be continuously with replenished fresh epoxy resin. Continuous'rotating.of the mandrel is essential and stopping of mandrel's rotation would result in Sagging and Dripping of the viscous Resin under gravitational forces. This would result in Resin rich lower . part and resin poor upper part. Hence, the necessities to treat the composite

Pressure vessel by IR, which can post cure the epoxy resin and stop the Sagging and Dripping process. The epoxy resins form an extremely important and versatile class of resins. These resins Exhibit excellent resistance to chemicals will adhere to glass and a variety of other Materials, show electrical insulation properties, and are relatively easy to use.
Benefits of the process:
1) The immediate immobilization of the Epoxy Resin.- The immobilization of the
" resin is controlled to provide sufficient gelation to prevent flow out of the part
but allow good wetting between layers, thus assuring even resin distribution, ■ the rapid gelation stage, in most cases, also eases handling during the heat-cure.
2) The advantages of the present invention include elimination of runs, drips,
migration, and resin rich/resin poor areas; even resin distribution, reduced
voids, lessens clean up and reduces resin waste.
* 3) The initial Low viscosity promotes exceptionally fast filling of parts and composite structures which can be rapidly controlled by IR Radiation.
4) Energy Costs.: The existing Oven having Finned SS coils consume 187.5 ' kW/hr units to cure a pressure tube( having 5-6mm thickness) having -a resin pot life of 220 mins. Therefore for 60 minutes pot life Epoxy resin the consumption would be 51.36.For the same given thickness. This further comes to 39.63 kW/hr. But under actual observation the consumption comes to 9 kW/hr. Thus there is a saving of 30 kW/hr.

5, We claim:
1. IR treated filament wound composite pressure vessels.
2. IR treated filament wound composite pressure vessels as claimed in claim 1, having an addition of UV additive in the resin itself for better UV resistant properties.
3. IR treated filament wound composite pressure vessels as claimed in claims 1 &
2, in which the resin gets spread out during IR treatment on the outer surface
and forming a protective coating against UV side effects.
4. IR treated filament wound composite pressure vessels as claimed in claims 1, 2
& 3, being able to reduce the curing time from 3 hours to 1.5 hrs and resulting
in decrease in cycle time of the product and increase in the productivity.
5. ' IR treated filament wound composite pressure vessels as claimed in claims 1, 2,
3 & 4, basically being IR treatment and not being-a heat curing processes and the heat curing being a part of the function and not the main function itself ' 6, IR treated filament wound composite pressure vessels as claimed in claims 1, 2,
3, 4 & 5, having the IR chamber being able to treat the different product
applications like FW Pressure tube of 8" dia/4inch dia, x 10 mtr length, and
composite gas cylinders of dia 250 mm dia x 1.2 mtr length./or any suitable
dimension in the gas cylinder range.
7. IR treated filament wound composite pressure vessels as claimed in claims 1,2,
3, 4, 5 & 6, in which the resin.immediately getting immobilized and being in
. constant rotation under very slow RPM 25.
. 8. . IR treated filament wound composite pressure vessels as claimed in claims 1, 2,
3, 4, 5, 6 & 7, having a provision to do dwell application or pass aeration on the
curing surface to get same curing effect throughout the vessel.
9. IR treated filament wound composite pressure vessels as claimed in claims 1, 2, 3, 4, 5, 6, 7 & 8, having the cost saving: the energy consumption being 25% of the normal heating chamber and the normal saving being to the tune of 70% of the original cost.

10. IR treated filament wound composite pressure vessels as claimed in claims 1, 2, 3, 4, 5, 6, 7, 8 & 9, having the treatment being able protect the vessel from fungus formation whenever exposed to open sunlight and when interfaced with brackish water.
11. IR treated filament wound composite pressure vessels as claimed in claims 1, 2, 3, 4, 5, 6, 7, 8, 9 & 10, having the tank/s with tank size of 13"X54" and having normal design pressure of 10 bar or 145 psi and having a test pressure of 11.5 bar or 165 psi and having design burst pressure of 40 bar or 580 psi and the actual burst pressure being withstood by the tank being 693 psi or 55.5, thus having 33% more safety factor.
6. Dated this 7 day of January, 2009