Title of Invention

"A PROCESS FOR PREPARATION OF BIO-DEGRADABLE PLASTICS"

Abstract

A process for preparation of bio-degradable plastics comprising the steps of modifying bio-polymer such as cellulose and starch taken in amount 10 to 60% by addition of 5 to 10% by weight of ammonium hydroxide and/or water and 10 to 25% by weight of urea and heating/cooking at temperature between 100 to 120°C for 15 to 20 minutes; granulating the lumpy form of the compound thus obtsiined, addition of 60 to 10% by weight of Linear low density polyethylene {LLDPE)/Low density polyethylene (LDPE)/High density polyethylene (HOPE)/ polypropylene (PP) and 10 to 25% of Ethylene Acrylic acid; mixing the compound and maintaining the temperature of 100 to 120°C followed by addition of 3 to 10% by weight of a pro-degradant/pro-oxidant selected from transition metal dithiocarbamates of iron, manganese, copper, zinc, cobalt, vanadium and cerium; addition of 1-5% by weight of dessicant, maintaining temperature in the range of 100 to 120°C; followed by extrusion at temperature between 100 to 150°C and subsequent blow drying.

Full Text

FIELD OF INVENTION This invention relates to a process for preparation of bio-degradable plastics. PRIOR ART Environmental hazards caused by the increasing use of plastics for shopping carry bags and other applications have led to growing concern, the world over, to substitute the plastics with environmentally degradable plastics. The bio-degradable plastics proposed in the present invention can be used for applications such as shopping carry bags, refuse sacks, compost bags, garment bags, bin liners, bread bags, agricultural films & nursery bags, disposable food containers, general purpose films for packaging, etc. Partially-degradable plastics known in the art: are starch based plastics comprising of starch coupled with polyethylene such as LDPE/I-LDPE etc A disadvantage of the above-mentioned plastics is that such starch based plastics disintegrate only in the soil and not in the environment. Another disadvantage of the above-mentioned plastics is that such plastics do not degrade completely Still another draw back of the above plastics is that such plastics do not conform to globally accepted protocols such as ASTM, DIN, J1S, CEN, etc. Further disadvantage of the above plastics is that these plastics arc hygroscopic in nature which restrict the use of such plastics to certain applications only. Yet further drawback of the above plastics is that during disintegration under the soil, only the starch component of the plastics is consumed by the micro-organisms whereas the essential elements namely hydrogen and carbon which form the back bone of the polymer matrix, are not returned to the environment. These plastics can therefore be reieiied to as disinlegiable or partially degradable plastics as for plastics to be termed as degradable, the hydrogen and carbon of the polymer must be returned to the environment. F.ven further drawback of the above plastics is that even after disintegration the remaining polymer material, after consumption of starch by micro-organisms, persists in the environment in much the same way as conventional plastics. OBJECTS OF THE PRESENT INVENTION An object of the present invention is to propose a process for the preparation of biodegradable plastics Another object of the present invention is to propose a process which provides plastics incorporating various active substances which allow for direct microbial assimilation and enhanced Oxo-degradation and UV- degradation leading to complete bio-degradation. Still another object of the present invention is to propose a process, which modifies the polymer matrix to make the polyolefmes Oxi-biodegradable which creates hydrophilic surface on the plastic which can be assimilated by micro-organisms in the soil. Further object of the present invention is to propose a process for preparation of biodegradable plastics which uses conventional processing equipment which makes the process cost-effective. Even further object of the present invention is to propose a process, which provides totally degradable or compostable products, which are environment friendly. The products degrade or compost when subjected to sunlight, heat and/or stress conditions which are commonly present in the environment. Yet further object of the present invention is to propose a process, which provides plastics which on bio-degradation turns into carbon-dioxide, water and biomass leaving absolutely no toxic by products. STATEMENT OF INVENTION According to this invention, a process for preparation of bio¬degradable plastics comprising the steps of modifying bio-polymer such as cellulose and starch taken in amount 10 to 60% by addition of 5 to 10% by weight of ammonium hydroxide and/or water and 10 to 25% by weight of urea and heating/cooking at temperature between 100 to 120°C for 15 to 20 minutes; granulating the lumpy form of the compound thus obtained, addition of 60 to 10% by weight of Linear low density polyethylene (LLDPE)/Low density polyethylene (LDPE)/High density polyethylene (HDPE)/ polypropylene (PP) and 10 to 25% of Ethylene Acrylic acid; mixing the compound and maintaining the temperature of 100 to 120°C followed by addition of 3 to 10% by weight of a pro-degradant/pro-oxidant selected from transition metal dithiocarbamates of iron, manganese, copper, zinc, cobalt, vanadium and cerium; addition of 1-5% by weight of dessicant, maintaining temperature in the range of 100 to 120°C; followed by extrusion at temperature between 100 to 150°C and subsequent blow drying. DESCRIPTION OF INVENTION For preparation of bio-dcgradable plastics of the present invention, bio-polymers such as cellulose, starch taken in quantity 10-60% by weight is modified by addition of ammonium hydroxide and/or water taken in quantity 5 to 10% by weight and urea taken in quantity 10 to 25% by weight. The mixture is introduced in a dispersion kneader and is heated/cooked at 100 to 120°C, either by oil heating and circulation mechanism in the jacket of the kneader or by attaching heaters to the jacket The constituents are mixed and the activity is carried out tor about 15 to 20 minutes. The compound so obtained is transferred to a dump extruder where the lumpy material(compound) is cut into small pieces and then extruded. The temperature level is maintained in the range of 100 to 120"C. The extrusion activity is carried out within a time frame of 15 to 20 minutes. The extruded strands are continuously cut through a water bath with the help of a die face cutter and circulation of water which prevents the strands/granules from sticking to the blade surface. The granules are blow dried and collected in a container and fed to a hoppei dryer and dried again for about 2 to 3 hours to eliminate any moisture that may might have remained with the granules. To the granules so obtained as above, 60-10% by weight of LDPE/ LLDPE/HDPE/PP is added followed by addition of 10-25% by weight of Ethylene Acrylic acid. The above are mixed in a kneader and the temperature is maintained at 100 to 120°C for a duration of 30 to 45 minutes. Subsequently a pro-oxidant or pro-degradant 3-10% by weight, selected from transition metal dithiocarbamates of iron, zinc, copper, cobalt, vanadium and cariurri, preferably iron dimethyl dithiocarbamate, is introduced into the kneader A dessicant I to 5 % bt weight is also added. The temperature is continuously maintained at100 to 120°C for 20 to 30 minutes. The compound is then transferred to a dump extruder where the lumpy material is cut into small pieces and then extruded. The temperature level is maintained in the range of 100° to 120°C for 20 to 30 minutes. The compound so obtained is then transferred to a dump extruder where the compound which is in the form of lumpy material, is cut into small pieces and the extruded. The temperature level is maintained in the range of 100 to 150°C. The extrusion activity is carried out within the time frame of 15 to 20 minutes. The extruded strands are continuously cut through a water bath with the help of die face cutter and circulation of water which prevents the strands/granules from sticking to the blade surface. The granules are blow dried and collected in a container. In order to eliminate any moisture that might have remained in the granules so obtained, these are fed into a hopper dryer and dried again for about 2 to 3 hours. The granules thus obtained can be used for various applications. WORKING EXAMPLE The invention will now be illustrated with a working example, which is intended to illustrate the working of the invention and is not intended to be taken restrictively to imply any limitation on the scope of the present invention. Example20g of cellulose, 5g of ammonium hydroxide and 15g of urea were taken in a dispersion kneader and the temperature being maintained at 110°C. To the granules obtained by extrusion, drying, etc as described in the above description, 40g of low density polyethylenc was introduced followed by addition of 15g of ethylene acrylic acid. The compound was mixed properly and temperature was maintained at 110°C for 30 minutes. Thereafter 5g of iron dimethyl dithiocarbamate and 2g of dessicant were added and temperature maintained at 110°C for 20 minutes The compound so obtained was cut into pieces and extruded The extruded strands were cut through a water bath and blow dried., obtaining the bio-degradable plastics of the present invention in the form of granulas. The property profiling of bio-degradable plastics for grades of linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) are tabulated in below. It is to be noted that the process of the present invention is susceptible to modifications, changes, adaptations by those skilled in the art. Such variant embodiments incorporating the concepts and features of the present invention, are intended to be within the scope of the present invention which is further set forth under the following claims:- WE CLAIM; 1. A process for preparation of bio-degradable plastics comprising the steps of modifying bio-polymer such as cellulose and starch taken in amount 10 to 60% by addition of 5 to 10% by weight of ammonium hydroxide and/or water and 10 to 25% by weight of urea and heating/cooking at temperature between 100 to 120°C for 15 to 20 minutes; granulating the lumpy form of the compound thus obtained, addition of 60 to 10% by weight of Linear low density polyethylene (LLDPE)/Low density polyethylene (LDPE)/High density polyethylene (HOPE)/ polypropylene (PP) and 10 to 25% of Ethylene Acrylic acid; mixing the compound and maintaining the temperature of 100 to 120°C followed by addition of 3 to 10% by weight of a pro-degradant/pro-oxidant selected from transition metal dithiocarbamates of iron, manganese, copper, zinc, cobalt, vanadium and cerium; addition of 1-5% by weight of dessicant, maintaining temperature in the range of 100 to 120°C; followed by extrusion at temperature between 100 to 150°C and subsequent blow drying. 2. A process for preparation of bio-degradable plastic as claimed in claim 1 wherein the said heating of mixture of bio-polymer, ammonium hydroxide and urea is carried out preferably 15 to 20 minutes. 3. A process for preparation of bio-degradable plastics as claimed in claim 1 wherein said pre-degradant/ pro oxidant is preferably iron dimethyl diothiocarbamate. 4. A process for preparation of bio-degradable plastic as substantially described and illustrated herein.

Documents:

673-DEL-2003-Abstract-(23-10-2008).pdf

673-del-2003-abstract.pdf

673-DEL-2003-Claims-(23-10-2008).pdf

673-del-2003-claims.pdf

673-DEL-2003-Correspondence-Others-(23-10-2008).pdf

673-del-2003-correspondence-others.pdf

673-del-2003-correspondence-po.pdf

673-DEL-2003-Description (Complete)-(23-10-2008).pdf

673-del-2003-description (complete).pdf

673-del-2003-form-1.pdf

673-del-2003-form-18.pdf

673-del-2003-form-2.pdf

673-DEL-2003-Form-3-(23-10-2008).pdf

673-del-2003-form-3.pdf

673-del-2003-gpa.pdf