Title of Invention

"A PROCESS FOR THE PREPARATION OF PLANT BASED ACRYLATE COMPOSITE"

Abstract

A process for the preparation of plant based acrylate composite : The present invention provides a process for the preparation of plant based acrylate composite having molecular weight in the range of 7,000 - 10,000 KD by reacting a alkyl acrylate with leach liquor of rind of selected plant material such as Punica granatum, myrobalan, valonea, sumac. The composite of the present invention has enormous potential application in leather processing industry as a tanning agent.

Full Text

The present invention relates to a process for the preparation of plant based acrylate composite. More particularly the present invention relates to a process for the preparation of plant based acrylate composite having molecular weight in the range of 7,000-10,000 KD. The composite of the present invention has enormous potential application in leather processing industry as a tanning agent. Various plant parts including nuts, pods, barks, leaves, and roots etc., are rich in tannin content and have, since time immemorial, been in use for the purpose of vegetable taning in the leather processing industry. The tannin is conventionally extracted by leaching process. Leaching is the extraction of soluble material from the insoluble plant material. For leaching this kind of plant material water is used for extracting the soluble material. In this leaching, where solid material (plant) is taken in a vessel and . 200%w/v of water is circulated in it a period of about 3 hours at 40-85°C to extract the soluble material. The solution is separated by filtration. The tannin content, however, varies from parts to parts depending on the type of the plant material. While the conventional vegetable tannins may either be of hydrolysable or condensed type, the former ensures better penetration as well as lighter shade on the final leather. Chemically, the hydrolysable tannins are the derivatives of either gallic acid or ellagic acid. The molecular weights in respect of the gallic acid derivatives of the hydrolysable tannins lie within the range of 7000 to 10000 KD. All other types of vegetable tannins are of much larger molecular weight as well as size, that adversely tell upon the penetration parameter of the tannin molecules into hides/skins while using for the purpose of tannage. As reported by Kanagaraj et al (Paper entitled " Tanning Studies on Punica granatum rinds" - presented in LERIG-95). Punica granutum rind has been found to contain gallic acid derivatives of the hydrolysable tannins, which has exhibited excellent penetration when used as self-tanning material for delimed cow hides. However, the major limitations associated with the gallic acid derivatives of the hydrolysable tannins are the following. a. The presence of the hydrophilic groups result in high water absorption to the extent of 170-180%iv/win leather. b. Shrinkage temperature of the resulting leather can be max. 80°C c. Filling effect of the tanstuff is very low in comparison to the other. The above limitations of the natural tanning materials have prompted the researchers to look for suitable alternatives, which include exploring possibilities of using synthetic polymeric compounds. Hidemann (Das Leder , 40, 234-241, 1989) initiated and studied the application of acrylates in leather processing. The molecular weights of the acrylate polymers, usually used in Leather processing, conventionally lie in the range of 5000 to 10000 KD, which ensures easy penetration of the molecules inside the leather fibers and subsequent cross linking of the fibers at multipoint, thereby resulting in adequate filling effect in the resulting leather. Moreover, the formation of more cross linkage inside the leather is likely to raise the hydrothermal stability of the leather depending on the extent of the cross linkage formation. No prior art is available on any composite prepared by polymerizing acrylates with the gallic acid extract derivatives available from the natural plant materials. The main object of the present invention is to provide a process for the preparation of plant based acrylated composite which obviates the drawbacks stated above. Another object of the present invention is to provide a process for the preparation of a plant based acrylate composite for using in leather processing. Accordingly the present invention is to provide a process for the preparation of plant based acrylate composite useful as tanning agent, which comprises iii) leaching rind of plant material as herein described having gallic acid as one of the constituents , at 40 - 85° C for a period of 3 hours , by conventional method , in aqueous medium, followed by separation of the leached liquor and subsequent adjustment of pH in the range of 5.5-6 , iv) adding alkyl acrylate having molecular weight in the range of 5000 - 10000 KD to the leached solution as obtained at step (i) wherein amount of said alkyl acrylate is 20 - 40% w/w of leached solution , at a temperature in the range of 30 - 60 ° C , with continuous stirring for a period of 4 hours to obtain the plant based acrylate composite. In an embodiment of the present invention, the plant based material used may be selected from Punica granatum, myrobalan, valonea, sumac, either individually or in different combination. In another embodiment of the present invention, the amount of water used for leaching may be minimum 200% w/v. In yet another embodiment of the present invention, the known method used for separation of the leached liquor may be such as filtration, decantation. In still another embodiment of the present invention, the alkyl acrylate used may be such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate. The process of the present invention is described below in detail. A plant material having gallic acid as one of the constituents is leaches at 40 -85C for a minimum period of 3 hours by conventional method in the water medium. The leached liquor is subjected to separation by known method and pH of the resulting liquor is adjusted in the range of 5.5 - 6 by using alkali. 20-40% w/w of an alkyl acrylate having molecular weight in the range of 5000 -10000 KD is then added to the solution with continuous stirring for a period of maximum 4 hrs, while maintaining the temperature of the reaction mixture in the range of 30 - 60C, to obtain the plant based acrylate composite. The novelty and non-obviousness of the present invention lies in the selection of the raw materials of acrylate as well as plant based extracts for the purpose of polymerization to form the plant based acrylate composite for using in leather process, whereby specific characteristics such as softness, grain tightness and hydrothermal stability to 95 °C, which are otherwise difficult to be achieved using either vegetable tannin or acrylic tannin individually, can be achieved in the final leather tanned by the composite. The following examples are given by way of illustration only and therefore should not be construed to limit the scope of present invention. Example 1 1 kg of punica granatum rind was collected and pulverized to a particle size of 5 mm using jaw crusher. The crushed material was taken in a beaker and 2000 ml of water was added to it with continuous stirring for leaching. The temperature was maintained at 40°C. After a period of 5 hrs pH of the leached liquor was found to be 3. 200 gms of sodium acetate solution was then added to the solution with constant stirring and the pH of the resulting solution was found to be 5.5. 300 ml of methyl acrylate polymer was then added to the above solution with continuous stirring. The temperature of the bath was maintained at 30 °C. After a period of 4 hours, the resulting solution was taken in a plastic container and stored. Example 2 1 kg of myrobolan rind was collected and pulverized to a particle size of 10 mm using jaw crusher. The crushed material was taken in a beaker and 3000 ml of water was added to it with continuous stirring for leaching. The temperature was maintained at 60°C. After a period of 4 hrs pH of the leached liquor was found to be 3.3. 250 gms of sodium acetate solution was then added to the solution with constant stirring and the pH of the resulting solution was found to be 5.7. 350 ml of ethyl acrylate polymer was then added to the above solution with continuous stirring. The temperature of the bath was maintained at 50 °C. After a period of 4 hours, the resulting solution was taken in a plastic container and stored. Example 3 1 kg of valonea rind was collected and pulverized to a particle size of 15 mm using jaw crusher. The crushed material was taken in a beaker and 4000 ml of water was added to it with continuous stirring for leaching. The temperature was maintained at 85°C. After a period of 5 hrs pH of the leached liquor was found to be 3.5. 270 gms of sodium acetate solution was then added to the solution with constant stirring and the pH of the resulting solution was found to be 6.0. 400 ml of butyl acrylate polymer was then added to the above solution with continuous stirring. The temperature of the bath was maintained at 60 °C. After a period of 4 hours, the resulting solution was taken in a plastic container and stored. Example 4 300 gm of punica granatum rind, 300 gm of myrobolan rind and 400 gm of valonea rind was collected and pulverized to a particle size of 15 mm using jaw crusher. The crushed material was taken in a beaker and 4000 ml of water was added to it with continuous stirring for leaching. The temperature was maintained at 70°C. After a period of 5 hrs pH of the leached liquor was found to be 3.5. 300 gms of sodium acetate solution was then added to the solution with constant stirring and the pH of the resulting solution was found to be 6.0. 300 ml of methyl acrylate polymer was then added to the above solution with continuous stirring. The temperature of the bath was maintained at 60 °C. After a period of 4 hours, the resulting solution was taken in a plastic container and stored. Example 5 10 kg of limed pelt was taken and then delimed with 1% ammonium sulfate to remove lime and other unwanted interfibrillary proteins. Then the delimed pelt was pickled to a pH of 4.5- using acetic acid at the level of 1 %. Then the pickled pelt was taken in the drum, the tannin composite of Punica granatum rind with methyl acrylate at the level of 20% was added to the drum in two feeds at half an hour interval. Drumming was continued for 2 hours to attain full penetration. Then the composite was fixed with 0.5% formic acid (diluted with 10% water) given in three feeds and the pH was brought down to 3.5. The final leather exhibited very good softness as well as grain tightness and shrinkage temperature of 95°C. The major advantages of the present invention are follows 1. The process of the present invention is very simple and involves no difficult parameter to be controlled. 2. The process does not require much investment and is very economical. 3. The leather manufactured by using the composite of the present invention can with stand a shrinkage temperature of 95°C and hence it can be used for the specific type of leathers including glaze finish leather. 4. The composite of the present invention, on being used as self tanning material, results in softness as well as grain tightening effect in the resulting leather, which becomes more amenable to buffing not only for making corrected grain leather but also for getting good nap while making suede leathers. 5. The composite ensures exhaustion of dye to the tune of 95% during leather processing. We Claim: 1. A process for the preparation of plant based acrylate composite useful as tanning agent, which comprises i) leaching rind of plant material as herein described having gallic acid as one of the constituents , at 40 - 85° C for a period of 3 hours , by conventional method , in aqueous medium, followed by separation of the leached liquor and subsequent adjustment of pH in the range of 5.5-6 , ii) adding alkyl acrylate having molecular weight in the range of 5000 - 10000 KD to the leached solution as obtained at step (i) wherein amount of said alkyl acrylate is 20 - 40% w/w of leached solution , at a temperature in the range of 30 - 60 ° C , with continuous stirring for a period of 4 hours to obtain the plant based acrylate composite. 2. A process as claimed in claim 1 , wherein the rind of plant material used is selected from Punica granatum, myrobalan, valonea, sumac either alone or in combination. 3. A process as claimed in claims 1 and 2 , wherein the amount of water used for leaching is minimum 200% w/w of rind of plant material used. 4. A process as claimed in claims 1 to 3, wherein the conventional method used for separation of the leached liquor is selected from filtration, decantation. 5. A process as claimed in claims 1 to 4, wherein the alkyl acrylate used is selected from methyl acrylate, ethyl acrylate, propyl acrylate butyl acrylate. 6. A process for the preparation of plant based acrylate composite ' useful as tanning agent, substantially as herein described with ' reference to the examples.

Documents:

1057-del-2001-abstract.pdf

1057-del-2001-claims.pdf

1057-del-2001-correspondence-others.pdf

1057-del-2001-correspondence-po.pdf

1057-del-2001-description (complete).pdf

1057-del-2001-form-1.pdf

1057-del-2001-form-18.pdf

1057-del-2001-form-2.pdf

1057-del-2001-form-3.pdf