Indian Patents. 252784:A PROCESS FOR PREPARING A CURING AGENT FOR EPOXY RESIN

Title of Invention	A PROCESS FOR PREPARING A CURING AGENT FOR EPOXY RESIN
Abstract	The present invention discloses the epoxy curing agents prepared by reacting cyclic fatty dicarboxylic acid/s with diamine/polyamine compound at a temperature range of 150 DEG C to 200 DEG C in presence of an aromatic solvent. The curing agents so prepared are useful for curing epoxy resins.

Full Text	FORM 2 THE PATENTS ACT. 1970 (39 of 1970) & THE PATENS RULES, 2003 COMPLETE SPECIFICATION [See section 10, Rule 13] NEW EPOXY CURING AGENT THE GODAVARI SUGAR MILLS LTD WHOSE ADDRESS IS FAZALBHOY BLDG., 45/47, MAHATMA GANDHI ROAD, FORT MUMBAI - 400 001 MAHARASHTRA, INDIA THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED. TITLE NEW EPOXY CURING AGENT FIELD OF INVENTION The present invention relates to the preparation of new epoxy curing agents which are new polyamidoamines based on cyclic fatty dicarboxylic acid/s as curing agent for epoxy resins. BACKGROUND ART Coatings based on epoxy resins are important industrial products. The largest volume of these products is used for the protection and decoration of large metal or concrete structures such as bridges, ships, industrial tanks, etc., where application of the coating must be performed under ambient conditions. Epoxy coatings of this type have proven themselves to offer an excellent combination of corrosion resistance, water resistance, abrasion resistance, solvent resistance and other desirable coatings properties, and do so in a cost effective manner. Most epoxy resin coatings designed for ambient application employ polyfunctional amines as the curing agent, either alone or in some cases in combination with other curing agents. They are described more fully in W.R. Ashcroft, Curing Agents for Epoxy Resins, in B. Ellis (ed.)t Chemistry and Technology of Epoxy Resins, Blackie Academic and Professional, London, 1993, pp 37-71. z Among these curing agents, polyamides are a particularly important class of curing agent for the formulation of coatings. Any of the higher polyethyleneamines can be employed in the preparation of polyamides, such as diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), or pentaethylenehexamine (PEHA). Polyamides are employed because they allow for the formulation of coatings with an excellent combination of water and corrosion resistance, most likely due to the hydrophobicity imparted by the cyclic fatty nature of the starting materials. They also can offer excellent flexibility and reasonable cure speeds (drying times). Polyamidoamines are another important class of curing agents. They are advantageous over polyamides to formulate coatings and related products. GB 789,108 discloses polyamides made by condensation of a polyamine with a saturated aliphatic acid of the formula HOOC(CH2)nCOOH where n is an integer from 3-12 or an aromatic dicarboxylic acid. US 4,732,966 discloses polyamides containing free amino groups derived from (a) a polybasic acid component comprising polymeric cyclic fatty acid (i.e., dimer cyclic fatty acid) together with from 10 to 90 mole%, based on the total acid component, of one or more aromatic dicarboxylic acids, and (b) a polyamine containing at least 50 mole% of one or more aliphatic polyamines containing at least three amino groups per molecule. 3 US 4,086,197 discloses polyamino-amide hardener prepared from 90 to 60 parts of at least one unsaturated monomeric cyclic fatty acid having at least 12 carbons, 10 to 40 parts of an acid having a molecular weight less than 200, 20 to 80 parts of a polyalkylene-polyamine, and 80 to 20 parts of isophorone diamine, with the ratio of acid to amine components being 1 to 2 eq. of acid per mole of amine. R.H.E Munn, Journal Oil and Coulor Chem. Assoc, 1987 (10), pp 300-304 describes the modification of traditional dimer acid-based polyamide curing agents with terephthalic, and particularly isophthalic acid. Such modification leads to good compatibility and dry speed and freedom from surface defects. U.S. Pat. No. 3,236,895 to J. M. Lee et al. teaches a series of polyoxyalkylenepolyamines. These diprimary amines are useful for curing epoxy resins. U.S. Pat. No. 3,467,393 to Legler (1969) teaches the use of a polyoxyalkylenepolyamine for curing a polyglycidyl ether of a polyhydric phenol. Homan's U.S. Pat. No. 2,783,214 (1957) discloses the curing of an epichlorohydrin-bisphenol resin-forming material at ambient temperature with a specific mixture of amines, i.e., a major amount of triethylene tetramine and a 4 minor amount of triethanolamine, in the presence of a highly reactive substance which will polymerize spontaneously in the presence of the stated amines. U.S. Pat. No. 4578412 to Sellstrom Kathy B; Waddill Harold G (1986) discloses the extended 1,2-epoxy-interactive polyamine curing compositions and a method for preparing such curing compositions from a 1,2-epoxy-interactive polyamine and a cured normally solid elastomeric polyurethane. The patent number EP1024159 discloses a Compositions of amine terminated polyamidoamine resins useful for curing epoxy resins comprising combinations of fatty monocarboxylic acids, aromatic mono- and dicarboxylic acids, and polyethyleneamines. SUMMARY OF INVENTION An object of the present invention is to provide a new curing agent for epoxy resin. The present invention relates to the preparation of new polyamidoamines based on cyclic fatty dicarboxylic acid/s as curing agent for epoxy resins. The cyclic fatty dicarboxylic acid/s are synthesized by Diels-Alder addition reaction of natural cyclic fatty acids, containing one or more double bonds on their backbone, with 2,4- Hexadienoic acid. The new polyamidoamines are synthesized by the condensation reaction of the cyclic fatty dicarboxylic acid and a diamine or polyamine as curing agent for epoxy resins. 5 These polyamidoamine curing agents possess certain desirable properties not found in the prior art polyamidoamine curing agents such as a combination of less curing time and higher equivalent weight. The cured epoxy coatings exhibit improved properties such as low blush and exudate, good surface appearance , acceptably fast dry times, gloss, good chemical resistance like xylene (double rubs), methyl ethyl ketone((double rubs), acid (5 % v/v HCI) (for 24 hours at 25 DEG C), alkali (5 % w/v NaOH) (for 24 hours at 25 DEG C), Salt spray resistance. DETAILED DESCRIPTION OF THE INVENTION In the current invention the cyclic fatty dicarboxylic acid/s used are synthesized by Diels Alder reaction of C18 monocarboxylic acids containing from 1 to about 3. units of unsaturation and 2,4-Hexanoic acid. Pure cyclic fatty acids or mixtures of pure cyclic fatty acids such as, oleic, linoleic, linolenic, and like acids may also be employed. The most preferred cyclic fatty acid is oleic acid. Usually, such cyclic fatty acids will be mixtures derived from triglycerides of natural products, Soybean oil, tall oil, sunflower oil, safflower oil, rapeseed oil, fish oils, vegetable oils, and oiticica oil. Polyamidoamines of the current invention are prepared by any number of processes known to those skilled in the art. Normally, the amines and acids are combined at temperatures ranging from about room temperature to about 100 DEG C. Heat is then supplied to raise the temperature as water is condensed from the reaction mixture. Heating is normally continued until the specified 6 amount of water is removed that will yield a product with the desired acid number. and amine number. The preparation of polyamidoamines of the present invention consist of the following steps. a) Preparation of the cyclic fatty dicarboxylic acid/s by the Diels Alder addition reaction of natural cyclic fatty acids, containing one or more double bonds on their backbone, preferably oleic acid with equimolar quantity of 2,4- Hexadienoic acid in presence of litharge as catalyst at a temperature between 140-240 DEG C under vigorous stirring (600-700 rpm) for a period between 4-24 hours. b) Reaction of the cyclic fatty dicarboxylic acid/s with diamine or poly amines in presence of a aromatic solvent at a temperature range of 150 - 200 DEG C for a period between 5 to 15 hours. Reasonable modifications of the invention disclose herein are well within the scope of those skilled in the art and are also intended to be within the scope of the present invention, the scope of the present invention is not intended to be limited by the specific examples set out herein, but rather is to be interpreted according to the claims. The present invention will be described with reference to the example below. Example 1. 282 grams (1 mole) of Oleic acid is added to a 1 liter 3-necked round bottom flask fitted with a stirrer, water condenser and thermometer pocket. 112 grams (1 7 mole) of 2,4- Hexadienoic acid and 3.94 grams of litharge is added to it with mixing. The mixture is heated to 180 DEG C for 6-8 hrs. The reaction mixture was cooled to room temperature when the cyclic fatty dicarboxylic acid is obtained. The reaction product had an acid number of 253 mg of KOH/g and an iodine value of 67.2 g of Iodine/1 00g of sample. 443.5 g (0.8 moles) of the cyclic fatty dicarboxylic acid (acid number about 253) and 60.0 g (2.4 moles) of ethylene diamine were mixed into a three-necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place. 45g of xylene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 19.15 mg of KOH/g and an amine number of 206 mg of KOH/g. Example 2 443.5 g (0.8 moles) of cyclic fatty dicarboxylic acid prepared as in Example 1 was further reacted with 247.68 (2.4 moles) of diethylene triamine were mixed into a three necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place 55g of xylene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 18.15mg of KOH/g. Example 3 443.5 g (0.8 moles) of Cyclic fatty dicarboxylic acid prepared as in Example 1 was reacted with 247.68 (2.4 moles) of diethylene triamine were mixed into a 8 three necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place 65g of toluene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 17.28mg of KOH/g. Example 4 443.5 g (0.8 moles) of Cyclic fatty dicarboxylic acid prepared as in Example 1 was reacted with 175.44 (1.2 moles) of triethylenetetramine were mixed into a three necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place 55g of xylene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 18.15mg of KOH/g. Example 5 443.5 g (0.8 moles) of Cyclic fatty dicarboxylic acid prepared as in Example 1 was reacted with 175.44 (1.2 moles) of triethylenetetramine were mixed into a three necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place 60g of toluene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 18.15mg of KOH/g. 9 WE CLAIM 1. A curing agent for epoxy resin comprising of, a. preparation of the cyclic fatty dicarboxylic acid/s by the Diels Alder addition reaction of natural cyclic fatty acids, containing one or more double bonds on their backbone, preferably oleic acid with equimolar quantity of 2,4-Hexadienoic acid in presence of litharge as catalyst at a temperature between 140-240 DEG C under vigorous stirring (600-700 rpm) for a period between 4-24 hours; b. reaction of the cyclic fatty dicarboxylic acid/s with diamine or poly amines in presence of a aromatic solvent at a temperature range of 150 DEG C to 200 DEG C for a period between 5 to 15 hours 2. A curing agent as claimed in claim 1 wherein cyclic fatty acids, containing one or more double bonds on their backbone, with 2,4-Hexadienoicacid. 3. A curing agent for epoxy resin as claimed in claim 1 wherein diamine or polyamine is selected from a group comprising of ethylene diamine, diethylene triamine, triethylene . tetra amine, isophorone diamine,m-xylylene diamine, trimethyl hexamethylene diamine. 10 4. A curing agent for epoxy resin as claimed in claim 1 wherein the aromatic solvent is selected from a group comprising of toluene, xylene. 5. A curing agent for epoxy resin as claimed in claim 1 wherein the condensation reaction is carried out at a temperature range between 150-200 DEGC, preferably at temperature range between 170 to 180 DEGC for 5 to 15 hours. Dated this 10th day of March, 2006. 11 Abstract The present invention discloses the epoxy curing agents prepared by reacting cyclic fatty dicarboxylic acid/s with diamine/polyamine compound at a temperature range of 150 DEG C to 200 DEG C in presence of an aromatic solvent. The curing agents so prepared are useful for curing epoxy resins. 12-

Full Text

FORM 2
THE PATENTS ACT. 1970
(39 of 1970)
&
THE PATENS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
NEW EPOXY CURING AGENT
THE GODAVARI SUGAR MILLS LTD WHOSE ADDRESS IS FAZALBHOY BLDG., 45/47, MAHATMA GANDHI ROAD, FORT MUMBAI - 400 001 MAHARASHTRA, INDIA
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

TITLE
NEW EPOXY CURING AGENT
FIELD OF INVENTION
The present invention relates to the preparation of new epoxy curing agents which are new polyamidoamines based on cyclic fatty dicarboxylic acid/s as curing agent for epoxy resins.
BACKGROUND ART
Coatings based on epoxy resins are important industrial products. The largest volume of these products is used for the protection and decoration of large metal or concrete structures such as bridges, ships, industrial tanks, etc., where application of the coating must be performed under ambient conditions. Epoxy coatings of this type have proven themselves to offer an excellent combination of corrosion resistance, water resistance, abrasion resistance, solvent resistance and other desirable coatings properties, and do so in a cost effective manner. Most epoxy resin coatings designed for ambient application employ polyfunctional amines as the curing agent, either alone or in some cases in combination with other curing agents. They are described more fully in W.R. Ashcroft, Curing Agents for Epoxy Resins, in B. Ellis (ed.)t Chemistry and Technology of Epoxy Resins, Blackie Academic and Professional, London, 1993, pp 37-71.
z

Among these curing agents, polyamides are a particularly important class of curing agent for the formulation of coatings. Any of the higher polyethyleneamines can be employed in the preparation of polyamides, such as diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), or pentaethylenehexamine (PEHA). Polyamides are employed because they allow for the formulation of coatings with an excellent combination of water and corrosion resistance, most likely due to the hydrophobicity imparted by the cyclic fatty nature of the starting materials. They also can offer excellent flexibility and reasonable cure speeds (drying times). Polyamidoamines are another important class of curing agents. They are advantageous over polyamides to formulate coatings and related products.
GB 789,108 discloses polyamides made by condensation of a polyamine with a saturated aliphatic acid of the formula HOOC(CH2)nCOOH where n is an integer from 3-12 or an aromatic dicarboxylic acid.
US 4,732,966 discloses polyamides containing free amino groups derived from (a) a polybasic acid component comprising polymeric cyclic fatty acid (i.e., dimer cyclic fatty acid) together with from 10 to 90 mole%, based on the total acid component, of one or more aromatic dicarboxylic acids, and (b) a polyamine containing at least 50 mole% of one or more aliphatic polyamines containing at least three amino groups per molecule.
3

US 4,086,197 discloses polyamino-amide hardener prepared from 90 to 60 parts of at least one unsaturated monomeric cyclic fatty acid having at least 12 carbons, 10 to 40 parts of an acid having a molecular weight less than 200, 20 to 80 parts of a polyalkylene-polyamine, and 80 to 20 parts of isophorone diamine, with the ratio of acid to amine components being 1 to 2 eq. of acid per mole of amine.
R.H.E Munn, Journal Oil and Coulor Chem. Assoc, 1987 (10), pp 300-304 describes the modification of traditional dimer acid-based polyamide curing agents with terephthalic, and particularly isophthalic acid. Such modification leads to good compatibility and dry speed and freedom from surface defects.
U.S. Pat. No. 3,236,895 to J. M. Lee et al. teaches a series of polyoxyalkylenepolyamines. These diprimary amines are useful for curing epoxy resins.
U.S. Pat. No. 3,467,393 to Legler (1969) teaches the use of a polyoxyalkylenepolyamine for curing a polyglycidyl ether of a polyhydric phenol.
Homan's U.S. Pat. No. 2,783,214 (1957) discloses the curing of an epichlorohydrin-bisphenol resin-forming material at ambient temperature with a specific mixture of amines, i.e., a major amount of triethylene tetramine and a
4

minor amount of triethanolamine, in the presence of a highly reactive substance which will polymerize spontaneously in the presence of the stated amines.
U.S. Pat. No. 4578412 to Sellstrom Kathy B; Waddill Harold G (1986) discloses the extended 1,2-epoxy-interactive polyamine curing compositions and a method for preparing such curing compositions from a 1,2-epoxy-interactive polyamine and a cured normally solid elastomeric polyurethane.
The patent number EP1024159 discloses a Compositions of amine terminated polyamidoamine resins useful for curing epoxy resins comprising combinations of fatty monocarboxylic acids, aromatic mono- and dicarboxylic acids, and polyethyleneamines.
SUMMARY OF INVENTION
An object of the present invention is to provide a new curing agent for epoxy
resin.
The present invention relates to the preparation of new polyamidoamines
based on cyclic fatty dicarboxylic acid/s as curing agent for epoxy resins.
The cyclic fatty dicarboxylic acid/s are synthesized by Diels-Alder addition
reaction of natural cyclic fatty acids, containing one or more double bonds on
their backbone, with 2,4- Hexadienoic acid.
The new polyamidoamines are synthesized by the condensation reaction of the
cyclic fatty dicarboxylic acid and a diamine or polyamine as curing agent for
epoxy resins.
5

These polyamidoamine curing agents possess certain desirable properties not found in the prior art polyamidoamine curing agents such as a combination of less curing time and higher equivalent weight. The cured epoxy coatings exhibit improved properties such as low blush and exudate, good surface appearance , acceptably fast dry times, gloss, good chemical resistance like xylene (double rubs), methyl ethyl ketone((double rubs), acid (5 % v/v HCI) (for 24 hours at 25 DEG C), alkali (5 % w/v NaOH) (for 24 hours at 25 DEG C), Salt spray resistance.
DETAILED DESCRIPTION OF THE INVENTION
In the current invention the cyclic fatty dicarboxylic acid/s used are synthesized by Diels Alder reaction of C18 monocarboxylic acids containing from 1 to about 3. units of unsaturation and 2,4-Hexanoic acid. Pure cyclic fatty acids or mixtures of pure cyclic fatty acids such as, oleic, linoleic, linolenic, and like acids may also be employed. The most preferred cyclic fatty acid is oleic acid. Usually, such cyclic fatty acids will be mixtures derived from triglycerides of natural products, Soybean oil, tall oil, sunflower oil, safflower oil, rapeseed oil, fish oils, vegetable oils, and oiticica oil.
Polyamidoamines of the current invention are prepared by any number of processes known to those skilled in the art. Normally, the amines and acids are combined at temperatures ranging from about room temperature to about 100 DEG C. Heat is then supplied to raise the temperature as water is condensed from the reaction mixture. Heating is normally continued until the specified
6

amount of water is removed that will yield a product with the desired acid number. and amine number.
The preparation of polyamidoamines of the present invention consist of the following steps.
a) Preparation of the cyclic fatty dicarboxylic acid/s by the Diels Alder addition reaction of natural cyclic fatty acids, containing one or more double bonds on their backbone, preferably oleic acid with equimolar quantity of 2,4- Hexadienoic acid in presence of litharge as catalyst at a temperature between 140-240 DEG C under vigorous stirring (600-700 rpm) for a period between 4-24 hours.
b) Reaction of the cyclic fatty dicarboxylic acid/s with diamine or poly amines in presence of a aromatic solvent at a temperature range of 150 - 200 DEG C for a period between 5 to 15 hours.
Reasonable modifications of the invention disclose herein are well within the scope of those skilled in the art and are also intended to be within the scope of the present invention, the scope of the present invention is not intended to be limited by the specific examples set out herein, but rather is to be interpreted according to the claims.
The present invention will be described with reference to the example below. Example 1.
282 grams (1 mole) of Oleic acid is added to a 1 liter 3-necked round bottom flask fitted with a stirrer, water condenser and thermometer pocket. 112 grams (1
7

mole) of 2,4- Hexadienoic acid and 3.94 grams of litharge is added to it with mixing. The mixture is heated to 180 DEG C for 6-8 hrs. The reaction mixture was cooled to room temperature when the cyclic fatty dicarboxylic acid is obtained. The reaction product had an acid number of 253 mg of KOH/g and an iodine value of 67.2 g of Iodine/1 00g of sample.
443.5 g (0.8 moles) of the cyclic fatty dicarboxylic acid (acid number about 253) and 60.0 g (2.4 moles) of ethylene diamine were mixed into a three-necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place. 45g of xylene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 19.15 mg of KOH/g and an amine number of 206 mg of KOH/g. Example 2
443.5 g (0.8 moles) of cyclic fatty dicarboxylic acid prepared as in Example 1 was further reacted with 247.68 (2.4 moles) of diethylene triamine were mixed into a three necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place 55g of xylene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 18.15mg of KOH/g. Example 3
443.5 g (0.8 moles) of Cyclic fatty dicarboxylic acid prepared as in Example 1 was reacted with 247.68 (2.4 moles) of diethylene triamine were mixed into a
8

three necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place 65g of toluene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 17.28mg of KOH/g. Example 4
443.5 g (0.8 moles) of Cyclic fatty dicarboxylic acid prepared as in Example 1 was reacted with 175.44 (1.2 moles) of triethylenetetramine were mixed into a three necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place 55g of xylene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 18.15mg of KOH/g. Example 5
443.5 g (0.8 moles) of Cyclic fatty dicarboxylic acid prepared as in Example 1 was reacted with 175.44 (1.2 moles) of triethylenetetramine were mixed into a three necked round bottom flask equipped with a mechanical stirrer, thermometer and Dean and Stark assembly. A solid formation takes place 60g of toluene was added to it and the reaction mixture was heated at 180 DEG C till 30 ml of water was removed azeotropically. The reaction product had an acid number of 18.15mg of KOH/g.
9

WE CLAIM
1. A curing agent for epoxy resin comprising of,
a. preparation of the cyclic fatty dicarboxylic acid/s by the Diels Alder
addition reaction of natural cyclic fatty acids, containing one or
more double bonds on their backbone, preferably oleic acid with
equimolar quantity of 2,4-Hexadienoic acid in presence of litharge
as catalyst at a temperature between 140-240 DEG C under
vigorous stirring (600-700 rpm) for a period between 4-24 hours;
b. reaction of the cyclic fatty dicarboxylic acid/s with diamine or poly
amines in presence of a aromatic solvent at a temperature range
of 150 DEG C to 200 DEG C for a period between 5 to 15 hours
2. A curing agent as claimed in claim 1 wherein cyclic fatty acids, containing one or more double bonds on their backbone, with 2,4-Hexadienoicacid.
3. A curing agent for epoxy resin as claimed in claim 1 wherein diamine or polyamine is selected from a group comprising of ethylene diamine, diethylene triamine, triethylene . tetra amine, isophorone diamine,m-xylylene diamine, trimethyl hexamethylene diamine.
10

4. A curing agent for epoxy resin as claimed in claim 1 wherein the aromatic solvent is selected from a group comprising of toluene, xylene.
5. A curing agent for epoxy resin as claimed in claim 1 wherein the condensation reaction is carried out at a temperature range between 150-200 DEGC, preferably at temperature range between 170 to 180 DEGC for 5 to 15 hours.

Dated this 10th day of March, 2006.

11
Abstract
The present invention discloses the epoxy curing agents prepared by reacting cyclic fatty dicarboxylic acid/s with diamine/polyamine compound at a temperature range of 150 DEG C to 200 DEG C in presence of an aromatic solvent. The curing agents so prepared are useful for curing epoxy resins.
12-

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Patent Number

252784

Indian Patent Application Number

351/MUM/2006

PG Journal Number

22/2012

Publication Date

01-Jun-2012

Grant Date

30-May-2012

Date of Filing

10-Mar-2006

Name of Patentee

GODAVARI BIOREFINERIES LTD

Applicant Address

SOMAIY BHAVAN, 45/47, MAHATMA GANDHI ROAD, FORT,MUMBAI-400 001, MAHARASHTRA,INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	JYOTI PHADKE	3/78, PRATIRAKSHA NGR. C.H.S.L., VAKOLA BRIDGE, SANTACRUZ (E), MUMBAI-400 055.
2	SANGEETA SRIVASTAVA	1001, BHASKARA, TIFR COLONY, COLABA, MUMBAI-400 005.
3	MALSHE V.C.	M.U.I.C.T. STAFF QUARTERS, ABOVE OLD HOSTEL M.U.I.C.T. MATUNGA MUMBAI-400 019.
4	MAHESHWARI KOMAL`	11/4, SHANTI NAGAR, S.G. ROAD MUMBAI-400 011.

PCT International Classification Number

C08L63/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA