Indian Patents. 216818:AN IMPROVED PROCESS FOR THE PREPARATION OF A NOVEL PROTEIN-ACRYLATE GRAFT COPOLYMER HAVING MOLECULAR WEIGHT UPTO 300 000"

Title of Invention	AN IMPROVED PROCESS FOR THE PREPARATION OF A NOVEL PROTEIN-ACRYLATE GRAFT COPOLYMER HAVING MOLECULAR WEIGHT UPTO 300 000"
Abstract	An improved process for the preparation of a novel graft copolymer having molecular weight upto 300 000 is provided using serum, a hitherto known waste material, as the proteinous source, thereby suggesting an economical option of waste utilisation, whereby the resulting copolymer finds potential application as binder in leather industry.

Full Text	The present invention relates to an improved process for the preparation of Protein acrylate novel graft copolymer having molecular weight upto 300 000. More particularly, the present invention relates to a process for the preparation of a protein-acrylate graft copolymer for application as thermostable binder in leather finishing and coating in printing industry. The binder of the present invention has potential application in leather finishing to get a very good lusture without masking the grain pattern. It may be used for the formulation of leather finishing formulation to be used either for glazed finish or resin finish. One of the important ingredients used for leather finishing is binder, which is essentially a kind of film forming material holding pigment and other finishing auxiliaries on a film on the surface of the leather to be finished. Conventionally, the binders are based either on protein like casein, albumin or on resin like acrylates. Binders are selected depending on the requirement of properties and end use of the final leather. As reported by Wurtele (Grebbereiwiss Prax, 28 (1), 107, 1976), methyl methacrylate polymer used for the purpose of leather finishing formed a very good film on the leather surface imparting high wet rub fastness. Anbazhagan et al (Journal of Applied Polymer Science, 30, 391 - 400, 1985) prepared a binder for leather finishing by graft copolymerising chlorinated rubber with ethyl acrylate, n-butyl methacrylate in toluene medium under nitrogen atmosphere at a temperature of 80°C in the presence of benzoyl peroxide as initiator. Since the binders containing only synthetic polymers are not biodegradable, they contribute significantly to the environmental pollution by way of posing the problem of waste disposal. Moreover, the resin binders cannot withstand the temperature of glazing and hence are not suitable for glaze finished leather, which require thermostable protein binder in the finishing formulation. The main limitation of the protein binder is, however, its poor wet rub fastness, which is usually more in'case of resin finished leather. In this way, it seems to be very difficult to get all the desirable properties of a film by using either of them individually. This has prompted the researchers to use a proteinous source as the backbone in the preparation of binder by graft copolymerising a resin onto the proteinous backbone to ensure that their combination can obviate the said limitations. Studniarski et al (Prezylad Skorzany, 40(8), 151, 1985) used potassium persulfate redox initiator system to prepare gelatin- acrylonitrile graft copolymer for using as binder in leather finishing. Another important protein, which has been used for leather finishing is casein. Lakshminarayana et al ( Journal of American Leather Chemists Association, 79, 398-403, 1984 ) used casein for grafting acrylonitrile -styrene and acrylonitrile - n-butyl methacrylate using potassium persulphate -triethanolamine redox system at 60° C. Since casein is essentially a milk protein, its application in leather industry as a backbone in the preparation of binder implies that it has to be diverted from food industry.thereby resulting in higher cost of prbduction. Attempt was made by Olteanu et al (Material Plastics (Bucharest), 18(1), 43- 47, 1981) to prepare heterogeneous mixtures of collagen hydrolyzates and acrylic monomer latexes at a pH in the range of 3-4, resulting in a product exhibiting stability to temperature only upto 60°C, which is not enough for leather finishing. Rao et al (Journal of Applied Polymer Science, 16, 975 - 986, 1970) grafted collagen powder with different vinyl monomers at a temperature of 60°C using the eerie ion initiator at pH 2.0. The pre-requisite of using eerie ion is that the pH has to be maintained around 2, which suggests careful monitoring of the reaction. One interesting feature in all the above protein-resin graft copolymers is that a film forming proteinous source has been used as the backbone for necessary grafting. Since all these proteinous sources have major applications either for medical purpose, or in food/pharmaceutical industry, the major limitation associated with all the above systems is their availability in abundant quantity for the purpose of leather finishing, whereby the cost of production of the binder goes up consequently. In this connection, a potential proteinous source is animal blood that is available in plenty in the slaughter houses. Usually, the animal blood is defibrinated by vigorous churning for the purpose of isolating red blood cells (RBC), which are used for preparing haemoglobin. The serum obtained after separating the RBC is a protein, which is discarded as waste. Unlike the conventional film forming proteins, serum is not a good film former. Another limitation of the serum is that it, being a protein, is susceptible to decay by proteolytic attack. In the hitherto known process film forming protein is used as backbone and need to be used in large quantities. However, in the * present process use of non-film forming protein processed from bovine serum is being used, thereby reducing the requirement of costly film forming protein which is in high demand in other industries. Thus this process makes use of waste material and makes it more economical. The main objective of the present invention is to provide an improved process for the preparation of a novel graft copolymer having molecular weight upto 300 000, which obviates the drawbacks stated above. Another objective of the present invention is to use a non-film forming proteinous source for the preparation of protein-acrylate graft copolymer. Yet another objective of the present invention is to use bovine serum, a hitherto considered slaughter house waste, as the proteinous source for the preparation of binder. Still another objective of the present invention is to provide a simple process to improve the film forming property of serum. Yet another objective of the present invention is to provide a process to carry out polymerisation at a pH in the range of 6-8. Still another objective of the present invention is to provide a process to prepare a binder having stability upto a temperature of 150°C. Accordingly the present invention provide an improved process for the preparation of a protein acrylate novel graft copolymer having molecular weight upto 300 000, which comprises i. solubilising 1-2% w/v of a conventional film forming natural protein characterized in that in non-film forming protein processed from bovine serum in a known manner to get a mixture of serum and film forming protein, ii. graft copolymerising the said mixture of proteins with an acrylic monomer such as herein described in the range of 25-50% v/v with reference to serum using a ratio varying from 4:1 to 8:1 (protein :monomer) in presence of 2 to 5% w/v conventional redox initiator(s), preferably persulfites, meta bisulfites of monovalent cations, 0.2-0.5% w/v of conventional crosslinking agents, 1-4% of v/v conventional plasticizer, preferably straight chain fatty alcohols in a known manner under stirring at temperature of 45-75°C at least for 5 min., adding conventional sterilising agent in the range of 0.5-2% w/v with reference to serum, such as herein described in the range of 0.3-1% w/v, after cooling to 20-30°C to get the novel graft copolymer. In an embodiment of present invention, the conventional film forming protein used may be such as fibrin, collagen, casein, gelatin, albumin. In another embodiment of the present invention, the acrylic monomer used may be such as hydroxy ethylmethacrylate, glycidyl methacrylate, methyl methacrylate, butyl methacrylate. In yet another embodiment of the present invention, the amount of the acrylic monomer used may be in the range of 12.5-25% v/vwith reference to serum. In still another embodiment of the present invention, the redox initiator used may be such as ammonium persulphate, potassium persulphate, sodium meta bisulphite, benzoyl peroxide either individually or in combination. In yet another embodiment of the present invention, the crosslinker used may be such as glutaraldehyde, formaldehyde, basic chromium sulphate, genipin. In still another embodiment of the "present invention, the plasticiser used may be such as ethylene glycol, glycerol, polypropylene glycol, polyethylene glycol, either individually or in combination. In still another embodiment of the present invention, the conventional sterilising agent used may be such as sodium benzoate,sodium metabisulfite, copper sulfate, lunacid. In yet another embodiment of the present invention, the amount of the conventional sterilising agent used may be in the range of 0.3-0.5% w/v with reference to serum. The protein-acrylate graft copolymer is prepared in the following way. Serum is heated with 1-2% w/v, of conventional film forming protein at a temperature in the range of 45-75°C and the resulting protein mixture is graft copolymerised with 12.5-25% v/v, of acrylic monomer in presence of 2-5% w/v, of redox initiator, 0.2-0.5% w/v, of crosslinker and 1-4% v/v, of plasticiser, added either simultaneously or in succession, at a temperature in the range of 30-75°C. While polymerising, the- reactants are stirred continuously and the completion of the polymerization is ascertained by the conventional titration method. The resulting graft copolymer emulsion is then stirred with 0.3-0.5% w/v, of known sterilising agent at a temperature in the range of 20 - 30° C to obtain the protein-acrylate graft copolymer. The novelty and non-obviousness of the present invention lies in the identification of a non film forming proteinous source of serum, which is otherwise discarded as waste adding to environmental pollution, for preparing a protein-acrylate copolymer, having such properties as are necessary for being used as film forming binder in leather finishing, thereby suggesting an economical process to create wealth out of waste. The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention. Example -1 1 lit. of serum was taken in a 2-litre flask and 10 g of gelatin was added to it with vigorous shaking. The flask was then connected to a 3-necked adopter and a thermometer was attached to one of the necks for monitoring the temperature. The contents in the flask were heated to 45°C. A mixture of 1g of sodium metabisulfite and 1g of potassium persulfate was dissolved in 15 ml of water taken in a beaker and the resulting solution was added to the flask drop by drop. 125 ml of methyl methacrylate was measured and added simultaneously dropwise to the flask through the adopter. The reaction mixture was stirred vigorously with the help of magnetic stirrer, while maintaining the temperature at 45°C throughout the reaction. After a period of 60 minutes, 10 ml of ethylene glycol and 2 ml of glutaraldehyde were added to the reaction mixture, while continuing the stirring. The reaction was then continued for another 5 minutes. The completion of the grafting reaction was ascertained by the following method. 100 ml of the reaction mixture was taken in a beaker and an equal amount of water was added to it. A mixture of 2 ml of aqueous hydroquinone solution and 0.5 ml of n-octyl alcohol was then added to the beaker with stirring.The whole reaction mixture was then distilled in a distillation flask and the distillate was collected in a measuring cylinder, provided with recirculating facility. The lower layer of the distillate was recirculated to the distilling flask to continue the distillation process until the upper organic layer remained constant. Formation of clear solution in the measuring cylinder confirmed the completion of the grafting reaction. The resulting emulsion of protein-acrylate graft copolymer was allowed to cool down to a temperature of 20°C. 3 ml of lunacid was added to the emulsion. The resulting emulsion was packed in a plastic container for storage. Example - 2 1 lit. of serum was taken in a 2 litre flask and 15 g of fibrin was added to it with vigorous stirring. The flask was then connected to a 3 necked 1 lit. of serum was taken in a 2 litre flask and 20 g of fibrin was added to it with vigorous stirring. The flask was then connected to a 3 necked adopter and a thermometer was attached to one of the necks for monitoring the temperature. The contents in the flask were heated to 55°C. A mixture of 1.5 g of ammonium persulphate and 1.5 g potassium persulfate was dissolved in 15 ml of water taken in a beaker and the resulting solution was added to the flask drop by drop. 175 ml of glycidyl methacrylate was measured and added dropwise to the flask through the adopter. The reaction mixture was stirred vigorously with the help of magnetic stirrer, while maintaining the temperature at 55°C throughout the reaction. After a period of 60 minutes, 20 ml of propylene glycol and 1.5ml of formaldehyde were added to the reaction mixture, while continuing the stirring . The reaction was then continued for another 5 mints. The completion of the grafting reaction was ascertained by the following method. 100 ml of the reaction mixture was taken in a beaker and an equal amount of water was added to it. A mixture of 2 ml of aqueous hydroquinone solution and 0.5 ml of n-octyl alcohol was then added to the beaker with stirring.The whole reaction mixture was then distilled in a distillation flask and the distillate was collected in a measuring cylinder, provided with recirculating facility. The lower layer of the distillate was recirculated to the distilling flask to continue the distillation process until the upper organic layer remained constant. Formation of clear solution in the measuring cylinder confirmed the completion of the grafting reaction. The resulting emulsion of protein-acrylate graft copolymer was allowed to cool down to a temperature of 25°C. 4gm of sodium meta bisulphite is added to the emulsion. The resulting emcilsion was packed in a plastic container for storage. Example - 3 1 lit. of serum was taken in a 2 litre flask and 20 g of collagen powder was added to it with vigorous stirring. The flask was then connected to a 3 necked adopter and a thermometer was attached to one of the necks for monitoring the temperature. The contents in the flask were heated to 75°C. A mixture of 2.5 g of ammonium persulphate and 2.5 g sodium bisulphite was dissolved in 15 ml of water taken in a beaker and the resulting solution was added to the flask drop by drop. 250ml of butyl methacrylate was measured and added dropwise to the flask through the adopter. The reaction mixture was stirred vigorously with the help of magnetic stirrer, while maintaining the temperature at 75°C throughout the reaction.. After a period of 60 minutes, 40ml of glycerol and 5ml of genipin were added to the reaction mixture, while continuing the stirring . The reaction was then continued for another 5 mints. The completion of the grafting reaction was ascertained by the following method. 100 ml of the reaction mixture was taken in a beaker and an equal amount of water was added to it. A mixture of 2 ml of aqueous hydroquinone solution and 0.5 ml of n-octyl alcohol was'then added to the beaker with stirring.The whole reaction mixture was then distilled in a distillation flask and the distillate was collected in a measuring cylinder, prodided with recirculating facility. The lower layer of the distillate was recirculated to the distilling flask to continue the distillation process until the upper organic layer remained constant. Formation of clear solution in the measuring cylinder confirmed the completion of the grafting reaction. The resulting emulsion of protein-acrylate graft copolymer was allowed to cool down to a temperature of 25°C. 4gm of copper sulphate is added to the emulsion. The resulting emulsion was packed in a plastic container for storage. Example - 4 1 lit. of serum was taken in a 2 litre flask and 20 g of collagen powder was added to it with vigorous stirring. The flask was then connected to a 3 necked adopter and a thermometer was attached to one of the necks for monitoring the temperature. The contents in the flask were heated to 75°C. A mixture of 2.5 g of ammonium persulphate and 2.5 g sodium bisulphite was dissolved in 15 ml of water taken in a beaker and the resulting solution was added to the flask drop by drop. 200ml of hydroxy ethylmethacrylate was measured and added dropwise to the flask through the adopter. The reaction mixture was stirred vigorously with the help of magnetic stirrer, while maintaining the temperature at 75°C throughout the reaction. After a period of 60 minutes, 2CTml of glycerol and 20 ml of polyethylene glycol and 5ml of genipin were added to the reaction mixture, while continuing the stirring . The reaction was then continued for another 5 mints. The completion of the grafting reaction was ascertained by the following method. 100 ml of the reaction mixture was taken in a beaker and an equal amount of water was added to it. A mixture of 2 ml of aqueous hydroquinone solution and 0.5 ml of n-octyl alcohol was then added to the beaker with stirring.The whole reaction mixture was then distilled in a distillation flask and the distillate was collected in a measuring cylinder, prodided with recirculating facility. The lower layer of the distillate was recirculated to the distilling flask to continue the distillation process until the upper organic layer remained constant. Formation of clear solution in the measuring cylinder confirmed the completion of the grafting reaction. The resulting emulsion of protein-acrylate graft copolymer was allowed to cool down to a temperature of 25°C. 4gm of copper-sulphate is added to the emulsion. The resulting emulsion was packed in a plastic container for storage. Though the document does not exemplify, casein and albumin can be used as film forming protein, while basic chrome sulfate and benzoyl peroxide can be used as crosslinking agent and initiator respectively. The main advantages of the present invention are the following. 1. The present invention provides a process to use a source of hitherto discarded waste material, which Would otherwise pollute the environment, for the preparation of a useful finishing auxiliary for leather industry, thereby suggesting even a simple commercially feasible process for the effective disposal of the said waste source. 2. Since the present invention has identified serum, a hitherto known waste material, for its effective use in leather industry, the suggested process is much cheaper in cost compared to those where the costly conventional proteins like collagen, casein are used. 3. It provides an economical process to prepare a film forming binder from a non-film forming proteinous source, thereby widening the potential source for the preparation of binder. 4. The binder prepared by the process of the present invention can be used for both glaze finish as well as resin finish. We Claim 1. An improved process for the preparation of a protein acrylate novel graft copolymer having molecular weight upto 300 000 which comprises: iii. solubilising 1-2% w/v of a conventional film forming natural protein characterized in that in non-film forming protein processed from bovine serum in a known manner to get a mixture of serum and film forming protein, iv. graft copolymerising the said mixture of proteins with an acrylic monomer such as herein described in the range of 25-50% v/v with reference to serum using a ratio varying from 4:1 to 8:1 (protein :monomer) in presence of 2 to 5% w/v conventional redox initiator(s), preferably persulfites, meta bisulfites of monovalent cations, 0.2-0.5% w/v of conventional crosslinking agents, 1-4% of v/v conventional plasticizer, preferably straight chain fatty alcohols in a known manner under stirring at temperature of 45-75°C at least for 5 min., adding conventional sterilising agent in the range of 0.5-2% w/vwith reference to serum, such as herein described in the range of 0.3-1% w/v, after cooling to 20-30°C to get the novel graft copolymer. 2. An improved process, as claimed in Claim 1, wherein the conventional film forming protein used is selected from fibrin, collagen, casein, gelatin, albumin. 3. An improved process, as claimed in Claims 1 and 2, wherein the acrylic monomer used is such as hydroxy ethylmethacrylate, glycidyl methacrylate, methyl methacrylate, butyl methacrylate. 4. An improved process, as claimed in Claims 1 to 3, wherein the redox initiator used is selected from ammonium persulphate, potassium persulphate, sodium meta bisulphite, benzoyl peroxide either individually or in combination. 5. An improved process, as claimed in Claims 1 to 4, wherein the crosslinker used is selected from glutaraldehyde, formaldehyde, basic chromium sulphate, genipin. 6. An improved process, as claimed in Claims 1 to 5 wherein the plasticiser used is selected from glycol, polyethylene glycol, either individually or in combination. 7. An improved process, as claimed in Claims 1 to 6, wherein the conventional sterilising agent used is selected from sodium benzoate,sodium metabisulfite, copper sulfate, lunacid. 8.An improved process for the preparation of a protein acrylate novel graft copolymer having molecular weight upto 300 000, substantially as herein described with reference to the examples.

Full Text

The present invention relates to an improved process for the preparation of Protein acrylate novel graft copolymer having molecular weight upto 300 000. More particularly, the present invention relates to a process for the preparation of a protein-acrylate graft copolymer for application as thermostable binder in leather finishing and coating in printing industry. The binder of the present invention has potential application in leather finishing to get a very good lusture without masking the grain pattern. It may be used for the formulation of leather finishing formulation to be used either for glazed finish or resin finish.
One of the important ingredients used for leather finishing is binder, which is essentially a kind of film forming material holding pigment and other finishing auxiliaries on a film on the surface of the leather to be finished. Conventionally, the binders are based either on protein like casein, albumin or on resin like acrylates. Binders are selected depending on the requirement of properties and end use of the final leather.
As reported by Wurtele (Grebbereiwiss Prax, 28 (1), 107, 1976), methyl methacrylate polymer used for the purpose of leather finishing formed a very good film on the leather surface imparting high wet rub fastness. Anbazhagan et al (Journal of Applied Polymer Science, 30, 391 - 400, 1985) prepared a binder for leather finishing by graft copolymerising chlorinated rubber with ethyl acrylate, n-butyl methacrylate in toluene medium under nitrogen atmosphere at a temperature of 80°C in the presence of benzoyl peroxide as initiator.

Since the binders containing only synthetic polymers are not biodegradable, they contribute significantly to the environmental pollution by way of posing the problem of waste disposal. Moreover, the resin binders cannot withstand the temperature of glazing and hence are not suitable for glaze finished leather, which require thermostable protein binder in the finishing formulation.
The main limitation of the protein binder is, however, its poor wet rub fastness, which is usually more in'case of resin finished leather. In this way, it seems to be very difficult to get all the desirable properties of a film by using either of them individually. This has prompted the researchers to use a proteinous source as the backbone in the preparation of binder by graft copolymerising a resin onto the proteinous backbone to ensure that their combination can obviate the said limitations.
Studniarski et al (Prezylad Skorzany, 40(8), 151, 1985) used potassium persulfate redox initiator system to prepare gelatin- acrylonitrile graft copolymer for using as binder in leather finishing.
Another important protein, which has been used for leather finishing is casein. Lakshminarayana et al ( Journal of American Leather Chemists Association, 79, 398-403, 1984 ) used casein for grafting acrylonitrile -styrene and acrylonitrile - n-butyl methacrylate using potassium persulphate -triethanolamine redox system at 60° C.

Since casein is essentially a milk protein, its application in leather industry as
a backbone in the preparation of binder implies that it has to be diverted from
food industry.thereby resulting in higher cost of prbduction.
Attempt was made by Olteanu et al (Material Plastics (Bucharest), 18(1), 43-
47, 1981) to prepare heterogeneous mixtures of collagen hydrolyzates and
acrylic monomer latexes at a pH in the range of 3-4, resulting in a product
exhibiting stability to temperature only upto 60°C, which is not enough for
leather finishing.
Rao et al (Journal of Applied Polymer Science, 16, 975 - 986, 1970) grafted
collagen powder with different vinyl monomers at a temperature of 60°C
using the eerie ion initiator at pH 2.0. The pre-requisite of using eerie ion is
that the pH has to be maintained around 2, which suggests careful
monitoring of the reaction.
One interesting feature in all the above protein-resin graft copolymers is that
a film forming proteinous source has been used as the backbone for
necessary grafting.
Since all these proteinous sources have major applications either for medical
purpose, or in food/pharmaceutical industry, the major limitation associated
with all the above systems is their availability in abundant quantity for the
purpose of leather finishing, whereby the cost of production of the binder
goes up consequently.
In this connection, a potential proteinous source is animal blood that is
available in plenty in the slaughter houses. Usually, the animal blood is

defibrinated by vigorous churning for the purpose of isolating red blood cells (RBC), which are used for preparing haemoglobin. The serum obtained after separating the RBC is a protein, which is discarded as waste. Unlike the conventional film forming proteins, serum is not a good film former. Another limitation of the serum is that it, being a protein, is susceptible to decay by proteolytic attack. In the hitherto known process film forming protein is used as backbone and need to be used in large quantities. However, in the
*
present process use of non-film forming protein processed from bovine serum
is being used, thereby reducing the requirement of costly film forming protein
which is in high demand in other industries. Thus this process makes use of
waste material and makes it more economical.
The main objective of the present invention is to provide an improved process
for the preparation of a novel graft copolymer having molecular weight upto
300 000, which obviates the drawbacks stated above.
Another objective of the present invention is to use a non-film forming
proteinous source for the preparation of protein-acrylate graft copolymer.
Yet another objective of the present invention is to use bovine serum, a
hitherto considered slaughter house waste, as the proteinous source for the
preparation of binder.
Still another objective of the present invention is to provide a simple process
to improve the film forming property of serum.
Yet another objective of the present invention is to provide a process to carry
out polymerisation at a pH in the range of 6-8.

Still another objective of the present invention is to provide a process to prepare a binder having stability upto a temperature of 150°C. Accordingly the present invention provide an improved process for the preparation of a protein acrylate novel graft copolymer having molecular weight upto 300 000, which comprises
i. solubilising 1-2% w/v of a conventional film forming natural protein
characterized in that in non-film forming protein processed from bovine serum in a known manner to get a mixture of serum and film forming protein,
ii. graft copolymerising the said mixture of proteins with an acrylic
monomer such as herein described in the range of 25-50% v/v with
reference to serum using a ratio varying from 4:1 to 8:1 (protein
:monomer) in presence of 2 to 5% w/v conventional redox initiator(s),
preferably persulfites, meta bisulfites of monovalent cations, 0.2-0.5%
w/v of conventional crosslinking agents, 1-4% of v/v conventional
plasticizer, preferably straight chain fatty alcohols in a known manner
under stirring at temperature of 45-75°C at least for 5 min., adding
conventional sterilising agent in the range of 0.5-2% w/v with reference
to serum, such as herein described in the range of 0.3-1% w/v, after
cooling to 20-30°C to get the novel graft copolymer.
In an embodiment of present invention, the conventional film forming protein
used may be such as fibrin, collagen, casein, gelatin, albumin.
In another embodiment of the present invention, the acrylic monomer used
may be such as hydroxy ethylmethacrylate, glycidyl methacrylate, methyl
methacrylate, butyl methacrylate.

In yet another embodiment of the present invention, the amount of the acrylic
monomer used may be in the range of 12.5-25% v/vwith reference to serum.
In still another embodiment of the present invention, the redox initiator used
may be such as ammonium persulphate, potassium persulphate, sodium
meta bisulphite, benzoyl peroxide either individually or in combination.
In yet another embodiment of the present invention, the crosslinker used may
be such as glutaraldehyde, formaldehyde, basic chromium sulphate, genipin.
In still another embodiment of the "present invention, the plasticiser used may
be such as ethylene glycol, glycerol, polypropylene glycol, polyethylene
glycol, either individually or in combination.
In still another embodiment of the present invention, the conventional
sterilising agent used may be such as sodium benzoate,sodium metabisulfite,
copper sulfate, lunacid.
In yet another embodiment of the present invention, the amount of the
conventional sterilising agent used may be in the range of 0.3-0.5% w/v with
reference to serum.
The protein-acrylate graft copolymer is prepared in the following way.
Serum is heated with 1-2% w/v, of conventional film forming protein at a
temperature in the range of 45-75°C and the resulting protein mixture is graft
copolymerised with 12.5-25% v/v, of acrylic monomer in presence of 2-5%
w/v, of redox initiator, 0.2-0.5% w/v, of crosslinker and 1-4% v/v, of
plasticiser, added either simultaneously or in succession, at a temperature in
the range of 30-75°C. While polymerising, the- reactants are stirred

continuously and the completion of the polymerization is ascertained by the
conventional titration method.
The resulting graft copolymer emulsion is then stirred with 0.3-0.5% w/v, of
known sterilising agent at a temperature in the range of 20 - 30° C to obtain
the protein-acrylate graft copolymer.
The novelty and non-obviousness of the present invention lies in the
identification of a non film forming proteinous source of serum, which is
otherwise discarded as waste adding to environmental pollution, for preparing
a protein-acrylate copolymer, having such properties as are necessary for
being used as film forming binder in leather finishing, thereby suggesting an
economical process to create wealth out of waste.
The following examples are given by way of illustration of the present
invention and therefore should not be construed to limit the scope of the
present invention.
Example -1
1 lit. of serum was taken in a 2-litre flask and 10 g of gelatin was added to it with vigorous shaking. The flask was then connected to a 3-necked adopter and a thermometer was attached to one of the necks for monitoring the temperature. The contents in the flask were heated to 45°C. A mixture of 1g of sodium metabisulfite and 1g of potassium persulfate was dissolved in 15 ml of water taken in a beaker and the resulting solution was added to the flask drop by drop.

125 ml of methyl methacrylate was measured and added simultaneously
dropwise to the flask through the adopter. The reaction mixture was stirred
vigorously with the help of magnetic stirrer, while maintaining the
temperature at 45°C throughout the reaction.
After a period of 60 minutes, 10 ml of ethylene glycol and 2 ml of
glutaraldehyde were added to the reaction mixture, while continuing the
stirring. The reaction was then continued for another 5 minutes.
The completion of the grafting reaction was ascertained by the following
method.
100 ml of the reaction mixture was taken in a beaker and an equal amount of
water was added to it. A mixture of 2 ml of aqueous hydroquinone solution
and 0.5 ml of n-octyl alcohol was then added to the beaker with stirring.The
whole reaction mixture was then distilled in a distillation flask and the
distillate was collected in a measuring cylinder, provided with recirculating
facility. The lower layer of the distillate was recirculated to the distilling flask
to continue the distillation process until the upper organic layer remained
constant. Formation of clear solution in the measuring cylinder confirmed the
completion of the grafting reaction.
The resulting emulsion of protein-acrylate graft copolymer was allowed to
cool down to a temperature of 20°C. 3 ml of lunacid was added to the
emulsion. The resulting emulsion was packed in a plastic container for
storage.

Example - 2
1 lit. of serum was taken in a 2 litre flask and 15 g of fibrin was added to it with vigorous stirring. The flask was then connected to a 3 necked 1 lit. of serum was taken in a 2 litre flask and 20 g of fibrin was added to it with vigorous stirring. The flask was then connected to a 3 necked adopter and a thermometer was attached to one of the necks for monitoring the temperature. The contents in the flask were heated to 55°C. A mixture of 1.5 g of ammonium persulphate and 1.5 g potassium persulfate was dissolved in 15 ml of water taken in a beaker and the resulting solution was added to the flask drop by drop.
175 ml of glycidyl methacrylate was measured and added dropwise to the flask through the adopter. The reaction mixture was stirred vigorously with the help of magnetic stirrer, while maintaining the temperature at 55°C throughout the reaction.
After a period of 60 minutes, 20 ml of propylene glycol and 1.5ml of formaldehyde were added to the reaction mixture, while continuing the stirring . The reaction was then continued for another 5 mints.
The completion of the grafting reaction was ascertained by the following method.
100 ml of the reaction mixture was taken in a beaker and an equal amount of water was added to it. A mixture of 2 ml of aqueous hydroquinone solution and 0.5 ml of n-octyl alcohol was then added to the beaker with stirring.The whole reaction mixture was then distilled in a distillation flask and the

distillate was collected in a measuring cylinder, provided with recirculating facility. The lower layer of the distillate was recirculated to the distilling flask to continue the distillation process until the upper organic layer remained constant. Formation of clear solution in the measuring cylinder confirmed the completion of the grafting reaction.
The resulting emulsion of protein-acrylate graft copolymer was allowed to cool down to a temperature of 25°C. 4gm of sodium meta bisulphite is added to the emulsion. The resulting emcilsion was packed in a plastic container for storage.
Example - 3
1 lit. of serum was taken in a 2 litre flask and 20 g of collagen powder was added to it with vigorous stirring. The flask was then connected to a 3 necked adopter and a thermometer was attached to one of the necks for monitoring the temperature. The contents in the flask were heated to 75°C. A mixture of 2.5 g of ammonium persulphate and 2.5 g sodium bisulphite was dissolved in 15 ml of water taken in a beaker and the resulting solution was added to the flask drop by drop.
250ml of butyl methacrylate was measured and added dropwise to the flask through the adopter. The reaction mixture was stirred vigorously with the help of magnetic stirrer, while maintaining the temperature at 75°C throughout the reaction..

After a period of 60 minutes, 40ml of glycerol and 5ml of genipin were added
to the reaction mixture, while continuing the stirring . The reaction was then
continued for another 5 mints.
The completion of the grafting reaction was ascertained by the following
method.
100 ml of the reaction mixture was taken in a beaker and an equal amount of
water was added to it. A mixture of 2 ml of aqueous hydroquinone solution
and 0.5 ml of n-octyl alcohol was'then added to the beaker with stirring.The
whole reaction mixture was then distilled in a distillation flask and the
distillate was collected in a measuring cylinder, prodided with recirculating
facility. The lower layer of the distillate was recirculated to the distilling flask
to continue the distillation process until the upper organic layer remained
constant. Formation of clear solution in the measuring cylinder confirmed the
completion of the grafting reaction.
The resulting emulsion of protein-acrylate graft copolymer was allowed to
cool down to a temperature of 25°C. 4gm of copper sulphate is added to the
emulsion. The resulting emulsion was packed in a plastic container for
storage.
Example - 4
1 lit. of serum was taken in a 2 litre flask and 20 g of collagen powder was added to it with vigorous stirring. The flask was then connected to a 3 necked adopter and a thermometer was attached to one of the necks for monitoring the temperature. The contents in the flask were heated to 75°C.

A mixture of 2.5 g of ammonium persulphate and 2.5 g sodium bisulphite was
dissolved in 15 ml of water taken in a beaker and the resulting solution was
added to the flask drop by drop.
200ml of hydroxy ethylmethacrylate was measured and added dropwise to
the flask through the adopter. The reaction mixture was stirred vigorously
with the help of magnetic stirrer, while maintaining the temperature at 75°C
throughout the reaction.
After a period of 60 minutes, 2CTml of glycerol and 20 ml of polyethylene
glycol and 5ml of genipin were added to the reaction mixture, while
continuing the stirring . The reaction was then continued for another 5 mints.
The completion of the grafting reaction was ascertained by the following
method.
100 ml of the reaction mixture was taken in a beaker and an equal amount of
water was added to it. A mixture of 2 ml of aqueous hydroquinone solution
and 0.5 ml of n-octyl alcohol was then added to the beaker with stirring.The
whole reaction mixture was then distilled in a distillation flask and the
distillate was collected in a measuring cylinder, prodided with recirculating
facility. The lower layer of the distillate was recirculated to the distilling flask
to continue the distillation process until the upper organic layer remained
constant. Formation of clear solution in the measuring cylinder confirmed the
completion of the grafting reaction.
The resulting emulsion of protein-acrylate graft copolymer was allowed to
cool down to a temperature of 25°C. 4gm of copper-sulphate is added to the

emulsion. The resulting emulsion was packed in a plastic container for
storage.
Though the document does not exemplify, casein and albumin can be used
as film forming protein, while basic chrome sulfate and benzoyl peroxide can
be used as crosslinking agent and initiator respectively.
The main advantages of the present invention are the following.
1. The present invention provides a process to use a source of hitherto
discarded waste material, which Would otherwise pollute the environment,
for the preparation of a useful finishing auxiliary for leather industry, thereby
suggesting even a simple commercially feasible process for the effective
disposal of the said waste source.
2. Since the present invention has identified serum, a hitherto known waste
material, for its effective use in leather industry, the suggested process is
much cheaper in cost compared to those where the costly conventional
proteins like collagen, casein are used.
3. It provides an economical process to prepare a film forming binder from a
non-film forming proteinous source, thereby widening the potential source
for the preparation of binder.
4. The binder prepared by the process of the present invention can be used
for both glaze finish as well as resin finish.

We Claim
1. An improved process for the preparation of a protein acrylate novel
graft copolymer having molecular weight upto 300 000 which comprises:
iii. solubilising 1-2% w/v of a conventional film forming natural protein characterized in that in non-film forming protein processed from bovine serum in a known manner to get a mixture of serum and film forming protein,
iv. graft copolymerising the said mixture of proteins with an acrylic monomer such as herein described in the range of 25-50% v/v with reference to serum using a ratio varying from 4:1 to 8:1 (protein :monomer) in presence of 2 to 5% w/v conventional redox initiator(s), preferably persulfites, meta bisulfites of monovalent cations, 0.2-0.5% w/v of conventional crosslinking agents, 1-4% of v/v conventional plasticizer, preferably straight chain fatty alcohols in a known manner under stirring at temperature of 45-75°C at least for 5 min., adding conventional sterilising agent in the range of 0.5-2% w/vwith reference to serum, such as herein described in the range of 0.3-1% w/v, after cooling to 20-30°C to get the novel graft copolymer.
2. An improved process, as claimed in Claim 1, wherein the conventional film
forming protein used is selected from fibrin, collagen, casein, gelatin,
albumin.
3. An improved process, as claimed in Claims 1 and 2, wherein the acrylic
monomer used is such as hydroxy ethylmethacrylate, glycidyl methacrylate,
methyl methacrylate, butyl methacrylate.

4. An improved process, as claimed in Claims 1 to 3, wherein the redox
initiator used is selected from ammonium persulphate, potassium
persulphate, sodium meta bisulphite, benzoyl peroxide either individually or in
combination.
5. An improved process, as claimed in Claims 1 to 4, wherein the crosslinker
used is selected from glutaraldehyde, formaldehyde, basic chromium
sulphate, genipin.
6. An improved process, as claimed in Claims 1 to 5 wherein the plasticiser
used is selected from glycol, polyethylene glycol, either individually or in
combination.
7. An improved process, as claimed in Claims 1 to 6, wherein the
conventional sterilising agent used is selected from sodium benzoate,sodium
metabisulfite, copper sulfate, lunacid.
8.An improved process for the preparation of a protein acrylate novel graft copolymer having molecular weight upto 300 000, substantially as herein described with reference to the examples.

Documents:

787-del-2000-abstract.pdf

787-del-2000-claims.pdf

787-del-2000-correspondence-others.pdf

787-del-2000-correspondence-po.pdf

787-del-2000-description (complete).pdf

787-del-2000-form-1.pdf

787-del-2000-form-19.pdf

787-del-2000-form-2.pdf

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Patent Number

216818

Indian Patent Application Number

787/DEL/2000

PG Journal Number

13/2008

Publication Date

31-Mar-2008

Grant Date

19-Mar-2008

Date of Filing

01-Sep-2000

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001,INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	CHELLAN ROSE	CENTRAL LEATHER RESEARCH INSTITUTE ADYAR, CHENNAI-600 020,INDIA
2	NATESAN SAMIVELU	CENTRAL LEATHER RESEARCH INSTITUTE ADYAR, CHENNAI-600 020,INDIA
3	UMMADISETTY VENKATESWARALU	CENTRAL LEATHER RESEARCH INSTITUTE ADYAR, CHENNAI-600 020,INDIA
4	RAMAKRISHNAN RAMESH	CENTRAL LEATHER RESEARCH INSTITUTE ADYAR, CHENNAI-600 020,INDIA
5	RAJU RAJINI	CENTRAL LEATHER RESEARCH INSTITUTE ADYAR, CHENNAI-600 020,INDIA
6	THOTAPALLI	CENTRAL LEATHER RESEARCH INSTITUTE ADYAR, CHENNAI-600 020,INDIA

PCT International Classification Number

C08F 2/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA