FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
PROVISIONAL / COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION
High enrgy absorbing glass fibre composites for automotive applications.
2. APPLICANT
(a) NAME MAHINDRA & MAHINDRA Ltd.
(b) NATIONALITY. Indian Company registered under the provisions of the
Companies Act, 1956.
(c) ADDRESS . R&D Center, Auto Sector 89,M.I.D.C, Nasik-422007,
Maharashtra State,India.
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL COMPLETE
The following specification describes the The following specification
invention. particularly descrjbfis-lfielnvention and
the maiyieHlfwhich it is to be performed.

TITLE: - HIGH ENERGY ABSORBING GLASS FIBRE COMPOSITES FOR AUTOMOTIVE APPLICATIONS Field of invention:
Present invention relates to glass fibre composites. More particularly the present invention relates to high energy absorbing glass fibre composites for automotive applications. Prior art:
Fibre reinforced Plastics, well known due to its high strength to weight ratio, used in various applications like Automotive, Chemical, Aerospace, Marine applications etc. Mostly in all the cases general purpose polyester resins are used due to its high strength, high modulus and brittle nature after proper curing. The Glass fibre reinforced composite basically involves a resin system, reinforcement system, Hardener system, Catalyst & Accelerator or reaction promoter. Resin system acts as matrix for reinforcement and hardener system imparts structural integrity and other mechanical properties. The General purpose resin system is based on o-Phthalic acid, of the formula (I) (ref. Fig 1) which gives high brittleness & modulus. The energy absorption values are typically in the range above 100G (as per IS15223:2002) while in automobile application the required range is <80G (as per IS15223:2002) because of safety norms. This is due to high stiff nature of macromolecular chain in backbone. This system is processed by Hand lay-up technique. In this process, specific proportion of hardener & resin system are mixed and applied as Gelcoat on the mould, above which reinforcement system is placed & packed with the same Resin-hardener combinations. The exothermic reaction between accelerator and catalyst provides necessary energy to initiate cross-linking reaction or curing at room temperature.
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Generally FRP composite consists of Reinforcement (Chopped Strand Mat)
and resin system, (Polyester) and hardener which is the binding material.
All together after curing forms the integrated structure, i.e., Fibre Reinforced
Plastics.
Resin:
The resin is an oligomer, which is the condensation product of dibasic
unsaturated anhydride, dibasic alcohol & dibasic acid. The maleic
anhydride (is the one of the chemical constituent in the system) with
unstauration gives the site for cross-linking.
By adjusting the ratio of saturated to Unsaturated acids the optimum cross linking sites can be imparted in the backbone. To control the cross-linking and increase the distance between adjacent cross-linking, chain extenders are added. Usage of o-Phthalic acid based saturated acids of formula (I) is common in general-purpose resin. Hardener system:
Styrene is the cross-linking agent. The oligomer formed in the condensation product of acid, alcohol and anhydride contains unsaturation group in their backbone. The added styrene attack the unsaturation site of oligomer, by free radical mechanism, this will be added and links the two macromolecules i.e., bridges the polymers, technically called as cross-linking or curing.
The ratio of resin to Styrene is 50-55:45-50 Reinforcement System:
Conventional composite structure contains chopped strand Mat (Fig.4) (CSM - Chopped Strand Matt. This is a randomly oriented glass fibre binded together like mat). Three layers of CSM are arranged to form the reinforcement system in conventional method. Fig.4 shows construction of conventional FRP system where in between two layers (6), (8) of polymer
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binder, CSM (7) is placed in three layers. This increases overall thickness
of the composite and hence increases the stiffness of the system.
Composition of Ingredients:
Resin to Accelerator to Catalyst ratio used is 100:1.5:1.5
Catalyst & Accelerators:
MEKP (Methyl ethyl ketone peroxide) & Cobalt Naphthenate are used as
catalyst - accelerator system used for this composite structure.
Deficiencies of prior art
The conventional FRP material system is highly brittle and very stiff, energy
absorption of the composite is very low >110G (as per IS15223:2002)
hence unsuitable for the automobile application.
Object and Summary of present invention:
The objective of the present invention is to provide high energy absorbing
composite structure having energy absorption values in the range 50G to
75G(as per IS15223:2002) to suit the automobile application.
The requirements can be achieved by imparting necessary flexibility by
introducing space for molecular mobility, by adjusting the reinforcement
system, controlling the hardener, catalyst & accelerator system (to achieve
optimum gelation at low exotherm)
High energy absorbing composite requirements are met by tailoring the
microlevel substituents:
1. Resin Modification
2. Hybrid Reinforcement structure
3. Composition of ingredients Resin
In this process, o-phthalic acid of formula-(I) is replaced with Iso-phthalic acid of formula (II) based saturated acid of which absorbs any shocks during and impact. So the impact energy is distributed uniformly & absorbed
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by the entire system. The damping or dissipation of absorbed energy is carried out by vibration of macromolecules in the given conformation. Hardener system:
Styrene is the cross-linking agent. The oligomer formed in the condensation product of acid, alcohol and anhydride contains unsaturation group in their backbone. The added styrene attack the unsaturation site of oligomer, by free radical mechanism, this will be added and links the two macromolecules i.e., bridges the polymers, technically called as cross-linking or curing. By proper control in the dosage of the styrene, optimum cross-link density for better energy absorption can be achieved. The ratio of resin to Styrene is 65:35 is used in the present invention. In conventional system the ratio used is between 50-55:45-50, while the ratio is modified in the present invention to 60-65:35-40. Reinforcement System;
Conventional composite structure contains chopped strand Mat (CSM - this is a randomly oriented glass fibre binded together like mat). Three layers of CSM are arranged to form the reinforcement system in conventional method. Three layers increase overall thickness of the composite and hence increase the stiffness of the system.
In this process the reinforcement system is constructed with one layer of CSM in the middle with woven fabric as top and bottom layers. This construction allows reduced thickness (due to lower thickness of Woven fabric compared to CSM), stiffness of the composite reduced without reduction in strength properties. Composition of Ingredients: Resin to Accelerator to Catalyst ratio:
This ratio conventionally maintained as 100:1.5:1.5 whereas in present invention it is changed to 100:1.5:1.3. This ratio will reduce the reacting
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potential between hardener & resin. This will reduce the of crosslink density & enhances molecular flexibility. Catalyst & Accelerators:
MEKP (Methyl ethyl ketone peroxide) & Cobalt Naphthenate are used as catalyst - accelerator system used for this composite structure.
Description of figers
Fig. 1 shows formula (I) of o-phthalic acid used in prior art
Fig 2 shows formula (II) of iso phthalic acid used in present invention
Fig 3 shows structure of glass fibre composite according to present
invention
Fig 4 shows prior art fibre reinforced plastic composite structure
Description
The foregoing objects of the invention are accomplished and the problems
and shortcomings associated with prior art techniques and approaches are
overcome by the present invention as described bellow in the preferred
embodiment.
This invention is illustrated in the accompanying drawings, through out
which like reference letters indicate corresponding parts in the various
figures.
Resin
In this process, Iso-phthalic acid based saturated acid of formula (II) which
absorbs any shocks during and impact. So the impact energy is distributed
uniformly & absorbed by the entire system. The damping or dissipation of
absorbed energy is carried out by vibration of macromolecules in the given
conformation.
Hardener system:
Styrene is the cross-linking agent
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. By proper control in the dosage of the styrene, optimum cross-link density for better energy absorption can be achieved. The ratio of resin to Styrene used in present invention is 60-65:35-40. Reinforced structure
In this process the reinforcement system is constructed with one layer of CSM in the middle (3) with woven fabric as top (2) and bottom (4) layers. This construction allows reduced thickness due to lower thickness of Woven fabric compared to CSM, stiffness of the composite reduced without reduction in strength properties. Layers (1) and (5) are hand laid on the above which are made of polymer binder. Composition of Ingredients of the polymer binder is as follows: Resin to Accelerator to Catalyst ratio 100:1.5:1.3
This ratio will reduce the reacting potential between hardener & resin. This will reduce the of crosslink density & enhances molecular flexibility.
Catalyst & Accelerators:
MEKP (Methyl ethyl ketone peroxide) & Cobalt Naphthenate are used as catalyst - accelerator system used for this composite structure-Energy absorption achieved by above process is 50Gto75G. The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or matter.
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The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention; which is defined by the scope of the following claims.
Advantages of invention
With maintaining the inherent property of FRP composites energy absorption is increased without any basic material & process change.


Dated this 2nd day of January 2007