Title of Invention	A DEGRADABLE POLYMERIC COMPOSITION A PROCESS THEREFORE AND THE PRODUCTS THEREOF
Abstract	The invention discloses a degradable polymer comprising of (i) 0.2 to 10% by wt. compatibilizer cum cation exchanging agent, (ii) 0.2 to 10% by wt. reinforcing agent selected from water-swellable polymer, (iii), 1.0 to 20% by wt. polyamide and balance (iv) polymeric blend consisting of (a) 5 to 45 % UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, (b) 5 to 30% biodegradable polymer of natural origin, and (c) 40 to 80% by wt of low density olefin capable of imparting desired mechanical properties and having crystallanity in the range of 40% to 90%. The invention also describes a process for preparation of the said polymer that involves preparing a polymeric blend by mixing thoroughly UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, a biodegradable polymer of natural origin, and a low density olefin optionally employing a wetting agent such as paraffin, thoroughly mixing the said mixture and compatibilizer and reinforcing agent optionally adding polyamide, subjecting the mixture so obtained to melt extrusion to get the polymeric composition in form of chips, and converting to desired articles, such as herein described, by conventional methods if so desired.

Title of Invention

A DEGRADABLE POLYMERIC COMPOSITION A PROCESS THEREFORE AND THE PRODUCTS THEREOF

Abstract

The invention discloses a degradable polymer comprising of (i) 0.2 to 10% by wt. compatibilizer cum cation exchanging agent, (ii) 0.2 to 10% by wt. reinforcing agent selected from water-swellable polymer, (iii), 1.0 to 20% by wt. polyamide and balance (iv) polymeric blend consisting of (a) 5 to 45 % UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, (b) 5 to 30% biodegradable polymer of natural origin, and (c) 40 to 80% by wt of low density olefin capable of imparting desired mechanical properties and having crystallanity in the range of 40% to 90%. The invention also describes a process for preparation of the said polymer that involves preparing a polymeric blend by mixing thoroughly UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, a biodegradable polymer of natural origin, and a low density olefin optionally employing a wetting agent such as paraffin, thoroughly mixing the said mixture and compatibilizer and reinforcing agent optionally adding polyamide, subjecting the mixture so obtained to melt extrusion to get the polymeric composition in form of chips, and converting to desired articles, such as herein described, by conventional methods if so desired.

Full Text	This invention relates to a degradable polymeric composition, a process therefore and products thereof. FIELD OF INVENTION: The invention particularly relates to a polymeric composition that is photo degradable as well as biodegradable. Further the invention relates to a multicomponent composition. The invention also provides a process for the preparation of the title product. The process according to the present invention employs readily available components. The process is simple to operate commercially feasible and cost effective. The invention also claims the products such as plastic films, containers packaging material involving the polymeric composition of the present invention particularly when prepared by the process of this invention. The products thus prepared have improved thermal sealing properties and superior mechanical properties. The products are suitable for using at low or subzero level temperatures BACKGROUND OF THE INVENTION: Plastics are used extensively in almost every field. Among the various applications, plastics are used mostly in packaging. The use of plastics has given rise to improved methods of packaging goods. For example, polyethylene and polypropylene plastic films, bags, bottles, Styrofoam cups, blister packages, and the like provide stable, relatively unbreakable, chemically resistant lightweight packaging. With the wide acceptance of thermoplastic articles the market size of plastic has grown to over 150 million tones and is expected to double by 2010. A reference can be made to USP 0040062884, Economic Times Polymer, June - July 2005. Plastics have also found wide spread use in other disposable products such as, for example, disposable personal care products such as diapers, disposable work tools/ instruments/garments, and other disposable garments. Though many advantages of plastics have lead to their increased usage in a variety of products, the increased usage, however, has resulted in accumulation of huge amount of solid waste, since the plastic must be disposed of after it is used and thereby has created a serious environmental problem. As a result of the stability and durability of plastics, however, they tend to remain in our environment for a long time, without decomposing after disposal. It has been estimated that over 50 percent of the annual tonnage of all manufactured synthetic polymers are applied as packaging materials and that 90 percent of this ends up as a component of urban garbage. It has also been estimated that recalcitrant plastic accumulates in our environment at a rate of 25 million tons per year. Burning of plastics is an unsatisfactory disposal solution, since this tends to discharge smoke that adds to air pollution and destruction of the ozone layer. Burial in a waste site is also not an effective means of disposal. Composting is also not advisable due to non-degradable nature of the plastics. Thus Landfill was the only adoptable disposal method. However, accumulation of plastics in our environment has tended to result in landfills becoming filled to capacity; unsightly litter destroying the scenery and landscape; and destruction of the living environment for marine life and other forms of life in turn impairing ecosystem as a whole. In an effort to resolve the environmental problem, several techniques have been adopted to attribute the degradable characteristics to the polymer. The need is further enhanced due to decreasing landfill space. The problem can also be solved by incorporating additives in certain ways with the polymeric compositions used to make plastics to increase the rate at which the plastic is degraded to environmentally friendly compounds. These additives, commonly called degradants, increase the rate of degradation of the plastic. The degradation could be photodegradation, biological degradation, and/or chemical degradation. However, blending of the degradants with the virgin polymer affects the other properties of the plastics such as mechanical strength and resistance to moisture. The existing art known to the inventor includes US Patent No. US2002028857. In accordance with this patent, there have been over 500 patents in the last thirty years. Yet none of these patents has led to products which have been successful in establishing appreciable markets in the overall plastics market due to following reasons: 1) the articles lacked sufficient strength, 2) the articles had poor shelf life, 3) the articles were too expensive, and/or 4) fabrication into a useful article was difficult. The invention relates to biodegradable and/or compostable polymeric composition in the form of hollow/filled isotropically oriented plastic microspheres with potential use for forming films, coatings, fibers, molded articles or thermoformed articles. US 200202885, US5,397,759, and US 5,225,230 also relate to compostable Biodegradable polymeric composition in form of micro-spheres that involve multistage process. Us Patent No. 5,334,520 related to Id's 'BIOPOL' advocates using po!y-beta-hydroxybutyrate (PHB) and polyhydroxyvalerate for the preparation degradable plastics. The patent claims to achieve advantage over the prior art disclosing employing genetically modified Escherichia coli (E. coli) by eliminating the stringent process and operational conditions. However, despite PHB's advantages over other materials, its high cost of production has hindered its performance in the market U.S. Pat. No. 3,840,512 discloses thermoplastic compositions containing a metal salt of a fatty acid and a free carboxylic acid. Compression molded films which included both the metal salt of a fatty acid and a free carboxylic acid exhibited shorter times before the film became embrittled when exposed to light than films containing only the metal prodegradant. U.S. Pat No. 3,941,759 discloses a degradable plastic containing an organic photo-sensitizer and at least one organic derivative of a transition metal. Degradation is initiated by a photo-oxidative reaction of the photosensitizer and is sustained by the organic derivative of a transition metal. The plastic will continue to oxidize in the dark after an initial exposure to ultraviolet light. U.S. Pat. No. 3,994,855 discloses thermoplastic polymers or copolymers of .alpha.-olefins containing one or more transition metals. The polymer compositions are degraded under the action of sunlight and/or ultraviolet light and may also be subject to thermal degradation. U.S. Pat. No. 4,101,720 discloses a degradable plastic composition that includes an organic polymeric material having dispersed therein at least one organic derivative of a transition metal and at least one readily autoxidizable organic material. U.S. Pat. No. 4,156,666 discloses a degradable polyolefin resin comprising a polyolefin, a fatty acid or ester of a fatty acid and a monohydric aliphatic alcohol, and optionally an inorganic filler. The resins are molding resins and degrade when subjected to sunlight. U.S. Pat. No. 4,256,851 discloses a degradable plastic composition comprising an organic polymeric material having dispersed therein at least one ethylenically unsaturated alcohol or ethylenically unsaturated ester derived therefrom as a readily autoxidizable substance. U.S. Pat. No. 4,360,606 discloses a plastic composition containing an organic photosensitizer and at least one readily autoxidizable organic substance. Exposure of the polymeric material to an artificial source of light or sunlight initiates a chemical degradation process. The initial photochemical reaction is followed by susbequent reactions that are essentially thermal (i.e., non-photochemical). The readily autoxidizable substance accelerates the thermal autoxidation step that follows the initial photochemical step. U.S. Pat. No. 4,461,853 discloses a controllably degradable vinyl polymer composition that contains a complex of two different metals. A combination of iron and nickel compounds provides enhanced photodegradation of the polymer composition. U.S. Pat. No. 4,476,255 discloses a plastic composition containing a photosensitizer. Exposure of the plastic composition to natural sunlight or artificial sources of ultraviolet light initiates degradation of the composition. U.S. Pat. No. 4,517,318 discloses a photodegradable styrene resin that comprises a styrene resin and at least one photodegradable agent selected from benzophenone, anthroquinone, fluorene, xanthone, phenylalkyl ketones, phenacyl halides, and derivatives of these compounds and optionally at least one photodegradable accelerator. U.S. Pat. No. 4,931,488 discloses thermoplastic polymer compositions that include a biodegradable substance, such as starch; a transition metal compound; and a fatty acid or ester of a fatty acid. The compositions may further include one or more other transition metal compounds to catalyze degradation of the polymer. The polymer compositions are degraded under the action of heat and/or ultraviolet light. U.S. Pat. No. 4,983,645 discloses that the addition of camphorquinone to polyethylene accelerates the photodegradation of the polymer when the polymer is exposed to ultraviolet light. U.S. Pat. No. 5,091,262 discloses a biodegradable multilayer polyethylene film produced by a conventional extrusion process. The inner layer of the film contains about 3 to 40 percent starch and the exterior layers comprise polyethylene and at least one prodegradant to facilitate degradation of the outer layers and expose the starch filled inner layers. However, the disadvantage attached with the starch based products is that the products are weak brittle and have short shelf life. Particularly the products loose strength when stored under tropical conditions. U.S. Pat. No. 5,096,939 discloses a polymeric composition with enhanced reactivity toward oxidative and/or photo-oxidative degradation. The rate of degradation is enhanced by incorporating at least one alkoxylated ethylenically unsaturated compound as an organic photosensitizer. The compositions may further include other readily oxidizable substances. U.S. Pat. No. 5,134,193 discloses a polyethylene copolymer modified to contain chromomorphic moieties, which absorb at wavelengths greater than 200 nm, such as para-substituted benzenes and anthracenes, chemically bonded thereto. The copolymer, when added to virgin polyethylene renders the composition more susceptible to ultraviolet radiation. U.S. Pat. No. 5,145,779 discloses a process for degrading €2 to Cg alpha olefin starch containing polymers with lignin degrading microorganisms. Us Pat. No. 5,281,681 describes a process for degradable polymer having ester group inserted in the backbone of polyethylene. The product is low molecular weight product. However, the process has to be performed at very temperature and pressure. The Chinese Patent number 95191396 reports a polymer such as microorganism polyester, aliphatic polyester, and Polylactic acid that attributes photo and/or biodegradable property to the product. The technology is very expensive. U.S. Pat. No. 5,258,422 discloses compostable and biodegradable thermoplastic compositions comprising a thermoplastic polymer, a hydrolytically unstable antioxidant, a pro-oxidant, an accelerator, and a property modifier. U.S. Pat. No. 5,308,906 discloses an extrudable elastomeric composition composed of an elastomer A-B-A' block copolymer, where A and A' are each a thermoplastic polymer endblock and B is a conjugated diene monomer having a low degree of residual ethylenic unsaturation, a polyolefin, and an effective amount of transition metal compound distributed in the blend of the polyolefin and block copolymer. The elastomeric composition degrades in thermally oxidative environments. U.S. Pat. No. 5,378,738 discloses a biodegradable plastic produced by adding a substance that imparts a hydrophilic property to the plastic so that the plastic is decomposed by Blasidomycetes. U.S. Pat. No. 5,444,107 discloses a degradable polymer composition consisting essentially of a thermoplastic polymer composition comprising primarily polylactic acid or a copolymer of lactic acid and another hydroxy-carboxylic acid and starch and/or modified starch. The degradation rate of the polymer composition is controlled by the varying the amount of starch and/or modified starch. U.S. Pat. No. 5,461,093 discloses a biodegradable polyethylene composition. The composition includes starch chemically bonding to polyethylene with a coupling agent, a radical initiator, a Lewis acid, an autooxidizing agent, and a plasticizer. U.S. Pat. No. 5,565,503 discloses a film of a biodegradable polyolefin resin. The resin contains fillers selected from the group including inorganic carbonate, synthetic carbonates, nepheline syenite, magnesium hydroxide, aluminum trihydrate, diatamaceous earth, mica, natural or synthetic silicas, calcined clay, or mixtures thereof and a metal carboxylate as a prodegradant. U.S. Pat. No. 5,854,304 discloses a chemically degradable/compostable additive package or concentrate that is added to polyolefins. The additive package is a combination of a metal carboxylate and an aliphatic poly hydroxy-carboxyl acid. U.S. Pat. No. 5,861,461 discloses a biodegradable plastic composition characterized in that a thermoplastic modified starch is chemically bonded by the use of a coupling agent to a matrix resin of polyethylene and a biodegradable polyester. U.S. Pat. No. 5,866,634 discloses a biodegradable polymer composition comprising polylactic acid mixed with a polyester type biodegradable polymer. U.S. Pat. No. 5,973,024 discloses a biodegradable plastic composition and a method for controlling the rate of biodegradation of the biodegradable plastic. The rate of degradation is controlled by adding a carbodiimide compound to the biodegradable plastic. The carbodiimide is mixed into the plastic by dissolving the plastic and carbodiimide in an organic solvent and then removing the organic solvent by distillation or by mixing the carbodiimide with the plastic by melt-kneading. WO 88/09354 discloses a degradable polymer composition that is a blend of a normally stable chemically saturated polymer and a less stable chemically unsaturated polymer or copolymer, an anti-oxidant active over a limited period of time, and a latent pro-oxidant, such as an organic salt of a transition metal. WO 92/11298 discloses a photodegradable thermoplastic composition that includes a first transition metal compound, a second transition metal compound, and an aromatic ketone. The second transition metal compound acts as a catalyst with the first transition metal compound to enhance degradation of the thermoplastic material. The aromatic ketone has a synergistic effect that increases photodegradation of the plastic. WO 94/13735 discloses a degradable thermoplastic compositions. The compositions include a thermoplastic polymer component combined with a directly biodegradable component, an oxidizable component, transition metal additives, and an aromatic ketone. The polymeric material degrades in three stages. The first stage is biological removal of the directly biodegradable component which results in mass reduction and a highly porous material. The second stage is chemical and results in oxidative shortening of the long polymer chains to decrease their molecular weight and the third stage involves biological metabolism of the low molecular weight fragments. The process is cost extensive and cumbersome. US Pat. No. 6,482,872 also teaches incorporation of degradants selected from (i) photodegradant comprises one or more of aliphatic or aromatic ketones, quinones, peroxides, hydroperoxides, azo compounds, organic dyes, latent sensitizers, aromatic hydrocarbons, or mixtures thereof; (ii) biodegradant comprises one or more of chitin, starch, cellulose, glucose derivatives, polysaccharides, poly-.beta.-hydroxybutylate, poly caprolactone, polyesters, carbodiimides, or mixtures thereof; and (iii) chemical degradant comprises one or more of a combination of a metal carboxylate and an aliphatic poly hydroxy-carboxyl acid, a combination of metal carboxylate and filler, or a transition metal complex. The degradants are generally added polymer immediately after the polymer is synthesized and while the polymer is still fluid to ensure proper homogeneous blend to overcome the drawbacks of the prior art that advocates addition of degradants to virgin polymer compositions by melting the virgin polymer or by master batching there by achieving cost effective technology with enhanced efficacy. US2004062884 relates to a multicomponent composition for photodegradable and biodegradable plastic articles, avoiding employing starch. The composition discloses using new bioactive material of chitin, casein and the like, with biodegradable aid component, photodegradable and auto-oxidation catalysis component, and nonmetallic minerals and the like. Under natural condition, the degraded material can be utilized by microorganism to release carbon dioxide and water, and acts as an eco-friendly plastic material. The process is not feasible for commercial purposes as it requires number of costly components in addition to being cumbersome. US 20050203208 discloses mineral filled polyester resin based degradable polymeric composition containing 10 to 50 wt % fillers. The fillers are selected from two different groups: the first consisting of block type fillers including inorganic carbonates, synthetic carbonates, feldspar, nepheline syenite, magnesium oxide, magnesium hydroxide, aluminum trihydrate, and diatomaceous earth; the second consisting of platy fillers including talc, mica, or calcined clays, all having a particle size less than 150 mesh. As can be seen from the herein above disclosure the prior art suffers from one or the other problems making it commercially unfeasible. The main drawbacks are : lack of adequate strength, poor shelf life, cost extensive, and/or require sophisticated infrastructure and stringent operational conditions. Thus there felt an imperative need for a degradable polymeric composition which is cost effective, easy to operate, technically and commercially viable, eco-friendly, having desired mechanical properties, extended shelf life and makes use of easily and abundantly available ingredients. After continuous and painstaking R & D work the inventors have arrived at a degradable polymeric composition employing high and low density olefins, saccharides, swellable polymer degradant in judicious manner. It is not possible to arrive at this composition without extensive human intervention and conducting extensive experiments. The prior art fails to give conclusive indication for arriving at the composition of this invention, which can have desired flexibility, shelflife, ability to use at varied temperature and complete degradation to minerals through photo and biodegradation. The novelty resides in making a functional polymeric blend, that is photodegradable as well as bio-degradable, into a packaging polymer using unique combination of ingredients particularly modified compatibilizer. The added advantage is that the polymer of the present invention is functional at subzero temperature. SUMMARY OF THE INVENTION: The main object of this invention is to provide a degradable polymeric composition avoiding if not eliminating completely the shortcomings of the existing processes. Other objective of the invention is to provide a polymeric multicomponent composition having improved mechanical properties and shelf life. Another object of this invention is to provide a degradable polymeric composition that is photo as well as biodegradable resulting in to minerilazation. Yet other object of this invention is to provide a degradable polymeric composition prepared using easily available ingredients. Yet another object of this invention is to provide a degradable polymeric composition comprising high molecular weight polymeric components, compatibilizer, and reinforcing agent. Still other object of this invention is to provide degradable polymeric composition useful for preparing packaging articles and packaging films particularly with improved thermal sealing property. Further, the articles prepared by using the composition of the present invention can be used effectively while maintaining its mechanical properties even at sub zero degree Celsius conditions. Still another object of this invention is to provide a process for preparing degradable polymeric composition, the title product of the present invention as defined herein above. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention. The term biodegradation means a process of degradation accomplished with microbial activity. The term photo degradation indicates the degradation taking place due to exposure to light either natural or artificial. STATEMENT OF INVENTION: Accordingly the present invention provides a degradable polymeric composition comprising of the following components by weight based on the total weight of the composition: (i) 0.2 to 10% by wt. compatibilizer cum cation exchanging agent, (ii) 0.0 to 10% by wt. reinforcing agent selected from water-swellable polymer, (iii) 0.0 to 20% by wt. polyamide and balance (iv) a polymeric blend such as herein described, A polymeric composition as claimed in claim 1 is photodegrable as well as biodegradable. According to one of the embodiment of this invention the polymeric blend comprising (a) 5 to 45 % UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, (b) 5 to 30% biodegradable polymer of natural origin, and (c) 40 to 80% by wt of low density olefin capable of imparting desired mechanical properties and having crystallanity in the range of 40% to 90%. In one of the embodiments of the present invention UV light susceptible polymeric component having crystallanity in the range of 40% to 70% used may be such as polypropylene. According to other embodiment of the present invention biodegradable polymer of naturel origin used may be such as saccharide preferably polysaccharide. According to other embodiment of the present invention the low density polyolefin used may be low density polyethylene According to another embodiment of the present invention the compatibilizer used may be such as copolymer containing maleic anhydride as one of the monomer having 0.2 to 10 % of maleic anhydride by wt of copolymer. According to yet other embodiment of the present invention the low density olefin capable of imparting desired mechanical properties and having crystallanity in the range of 40% to 90% used may be low density polyethylene. According to yet another embodiment of the present invention the reinforcing agent capable of swelling may be such as clay of smectite group, preferably clay that is treated with oxidizing agent after successive sieving. The polyamide used may be such as nylon, preferably having crystallanity in the range of 40% to 60%. The polymeric composition of the present invention preferably comprisiing of the following components by weight based on the total weight of the composition: (a) 5 to 45 % Polypropylene, (b) 5 to 30 % polysaccharide, (c) 40 to 80 % low density polyethylene (LDPE), (d) 0.2 to 10 % co-polymer containing maleic anhydride as one of the monomers, (e) 0.2 to 10 % modified smectite clay, and (f) 1.0 to 20 % polyamide (nylon-6) In accordance with the other aspect of this invention there is provided a process for preparing the degradable polymeric composition comprising of steps: (a) preparing a polymeric blend by mixing thoroughly UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, a biodegradable polymer of natural origin, and a low density olefin optionally employing a wetting agent such as paraffin, (b) thoroughly mixing the said mixture and compatibilizer and reinforcing agent optionally adding polyamide, (c) subjecting the mixture so obtained to melt extrusion to get the polymeric composition in form of chips, and converting to desired article by conventional methods if so desired. The polymeric blend in step (a) may be prepared by compounding UV light susceptible polymeric component and a biodegradable polymer by melt extrusion, then adding the compounded product to low density olefin selected from low density polyethylene (LDPE). DETAILED DESCRIPTION: In the present invention polypropylene a UV susceptible olefin is blended with polysaccharide preferably modified polysaccharide and then the blend so obtained is mixed with polyethylene to obtain polymeric composition useful for preparing a photo as well as biodegradable plastic articles such as films, molded material/containers, and fibres. It may be worthwhile to mention here that though polypropylene and polyethylene are of polyolefin origin, pose problems in forming homogeneous mixture due to difference in crystallanity and other microstructure the two components. The presence of methyl group attached to alternate carbon atoms on the chain backbone of polypropylene is responsible in altering the properties of polypropylene. A reference can be made to an article by J.A. Brydson, Plastic materials, fifth edition, Butterworth, 1989, p.237. In the present invention a copolymer containing maleic anhydrideas one of the monomers has been employed as compatibilizer. This co-polymer facilitates the blending of polypropylene and polyethylene. Additionally the said copolymer also acts as cation exchange agent for smectite clay used as reinforcing agent. Smectite clay is known for its swelling property when contacted with water. It is known to be of expanding lattice type in which polymeric component can be reacted or accommodated. The group of clay can be easily modified by a compound capable of exchanging cations and thus can be incorporated in the polymeric matrix without any hiderence. The clay employed in the present invention is modified to a nano clay by successive sieving and chemically treating with oxidizing agent selected from hydrochloride, peracetic acid, perchloric acid, or hydrogen peroxide. The structural details of the modified clay is a subject matter of Indian Patent application No. 1354/DEL/2005 and is incorporated in entirety by way of reference in this application. Polyamide helps improving physical properties whenever incorporated. The composition is prepared as detailed herein above. Physical mixture of degradable polymer and polymer susceptible to UV light is compounded by melt extrusion in a twin extruder. The polymeric bio-photo degradable composition is thus made in the form of compounded cylindrical chips of about 2 to 3mm diameter and 2 to 4 mm length. The chips are then added to LDPE in a polyethylene bag/container and tumbling it thoroughly before putting in to extruder. This mixing may be made more uniform by addition of small quantity of light paraffin oil say 0.1 to 0.5 % by weight of the total weight of chips and LDPE granules. Compatibilizer and reinforcing agent are then added and the contents are again tumbled to ensure proper mixing. The pre wettings of chips by paraffin oil helps in proper adherence of powdery particles of the compatibilizer and reinforcing agent and thereby ensure uniform mixing. Twin extruder used for melt extrusion may be co-rotating or counter-rotating type. Blown films were made using the compounded chips in a blown film machine having seven heating zones of graded temperature between 100 to 230°C. Alternately the polymeric blend comprising of degradable polymer, polymer susceptible to UV light and LDPE is taken in a polyethylene bag/container and tumbling it thoroughly in presence of of small quantity of light paraffin oil say 0.1 to 0.5 % by weight of the total weight of chips and LDPE granules. Compatibilizer and reinforcing agent are then added and the contents are again tumbled to ensure proper mixing. The pre wettings of chips by paraffin oil helps in proper adherence of powdery particles of the compatibilizer and reinforcing agent and thereby ensure uniform mixing. The composition thus obtained is compounded by melt extrusion in a twin extruder. The polymeric bio-photo degradable composition is thus made in the form of compounded cylindrical chips of about 2 to 3mm diameter and 2 to 4 mm length. Twin extruder used for melt extrusion may be co-rotating or counter-rotating type. Blown films were made using the compounded chips in a blown film machine having seven heating zones of graded temperature between 100 to 230°C. The invention is further illustrated with the examples. However, these are purely for the purpose of illustration should not construe, in any way, the scope of protection intended to seek. EXAMPLE 1: 0.32 kg polypropylene (PP) (MFI - 0.7g/10min) and 0.48 kg polysaccharide were taken in a polyethylene bag of 5 kg capacity. The content was then melt extruded in a co-rotating extruder keeping the temperature of the final melt at 240°C. The chips thus prepared were then missed with 2.88 kg LDPE (MFI- 0.9 g/lOmin). 40g polyethylene - co-ethyl acrylate-co-maleic anhydride (EM) having melting point 92 °C , and maleic anhydride content of 3%by wt of polymer, and 32g clay were then added to the content and mixed thoroughly. The mixture was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C. EXAMPLE 2: 2.72 kg LDPE (MFI- 0.9 g/lOmin) 0,48 kg PP and 0.48 kg polysaccharide were taken in a polyethylene bag of 5 kg capacity. 6g of light paraffin oil was added to the content and tumbled to have proper mixing. 40g polyethylene - co-ethyl acrylate-co-maleic anhydride (EM) having melting point 92°C , and maleic anhydride content of 3%by wt of polymer, and 32g clay were then added to the content and mixed thoroughly. The mixture was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C. EXAMPLE 3 & 4: A polymeric composition was made using components and the process as described in Example 1 and 2 except that 25g of copolymer of styrene maleic anhydride, butyl acrylate, 2-ethylhexyl arcylate and methacrylic acid containing 28% maleic anhydride (SM) by wt. and having MP 185°Cwas employed as compatabilizer a in place of EM. Further the compositions were made with or without adding clay. The mixture was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C. EXAMPLE 5: A polymeric composition was made using components and the process as described in Example 3 except change in the quantity of LDPE, PP, and polysaccharide used that was 2.88 kg, 0.32 kg, and 0.32 kg respectively. EXAMPLE 6: 0.32 kg PP (MFI 0.7g/10min), 2.50 kg LDPE (MFI 0.9g/10 min.), and 0.32 kg poly saccharide and 0.32 kg polyamide (nylon 6 having MP 215°C) were taken in taken in a nr»1v»th\/1»np haa rtf f\ \ca ranar.itv and f\a nf lioht naraffin nil was added tumbled to have proper mixing. 40.0 g of SM (compatibilizer) and 25 g of clay were added and mixed thoroughly. The content then was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C. EXAMPLE 7: 0.32 kg PP (MFI 0.7g/10min), 2.50 kg LDPE (MFI 0.9g/10 min.), and 0.32 kg poly saccharide and 0.32 kg polyamide (nylon 6 having MP 215°C) were taken in taken in a polyethylene bag of 6 kg capacity and 6g of light paraffin oil was added tumbled to have proper mixing. 40.0 g of SM (compatibilizer) was added and mixed thoroughly. No clay was added. The content then was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C. Raman spectra of films prepared in accordance with Examples 3 & 4 are shown in figures 1 and 2 accompanying this specification. The spectra show the corresponding standard Raman shifts for each components. The following tables show the properties of the products prepared using polymeric composition of this invention. Table 1 shows the tensile strength of the films prepared from the polymeric composition of Examples 3,4, 6, and 7. TABLE 1 (Table Remove) Table 2 shows the tensile data of film 3 and 4 after exposure to solar radiations at an altitude of 26° 13' N and a latitude of 78° 13'E during Nov. -Jan. for 30 days and 45 days. TABLE 2 (Table Remove) It may be worthwhile to mention here that though the polymer prepared without employing clay is effective and has phtodegradability and biodegradability to the extent of 50% and 31% respectively, addition of clay enhances the same to the tune of 60% and 40% respectively. Any variations in the proportions as obvious to the person skilled in the art may be encompassed in the ambit of the protection sought in this application WE CLAIM: 1. A degradable polymeric composition comprising of the following components by weight based on the total weight of the composition: (i) 0.2 to 10% by wt. compatibilizer cum cat ion exchanging agent, (ii) 0.0 to 10% by wt. reinforcing agent selected from water-swellable polymer, (iii) 0.0 to 20% by wt. polyamide and balance (iv) polymeric blend such as herein described. 2. A polymeric composition as claimed in claim 1 is photodegrable as well as biodegradable. 3. A polymeric composition as claimed in claims 1 and 2 wherein the polymeric blend comprising (a) 5 to 45 % UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, (b) 5 to 30% biodegradable polymer of natural origin, and (c) 40 to 80% by wt of low density olefm capable of imparting desired mechanical properties and having crystallanity in the range of 40% to 90%. 4. A polymeric composition as claimed in claims 1 to 3 wherein the UV light susceptible polymeric component having crystallanity in the range of 40% to 70% used is polypropylene. 5. A polymeric composition as claimed in claims 1 to 3 wherein the biodegradable polymer used is saccharide preferably polysaccharide. 6. A polymeric composition as claimed in claims 1 to 3 wherein the low density polyolefm capable of imparting desired mechanical properties and having crystallanity in the range of 40% to 90% used is polyethylene 7. A polymeric composition as claimed in claim 1 wherein the compatibilizer used is copolymer containing maleic anhydride as one of the monomer having 0.2 to 10% of maleic anhydride by wt of copolymer preferably polyethylene- co-ethyl acrylatc-co-maleic anhydride (\;.M) or copolymer of styrene maleic anhydride, butyl acrylale, 2-ethylhcxyl arcylate and methacrylic acid. 8, A polymeric composition as claimed in claim 1 wherein the reinforcing agent selected from poKmci capable of swelling used is clay of smectite group, preferably clay that is treated with oxidizing agent after successive sieving. A polymeric composition as claimed in claim 1 wherein the polyamide used is nylon, preferably the one having crystallanity in the range of 40% to 60%. 9. A polymeric composition as claimed in claim 1 comprisiing of the following components by weigh! based on the total weight of the composition: (a) 5 to 4.5 % Polypropylene, (b) 5 to 30 "/» polysaccharide, 80 % Sow density polyethylene (LDPE), (d) 0.2 to 10 % co-polymer containing maleic anhydride as one of the monomers,, <:e to modified smectite clay and polyamide> 11. A process ior preparing the degradable polymeric composition comprising of steps: (a) preparing a polymeric blend by mixing thoroughly UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, a biodegradable polymer of natural origin, and a low density olefin optional!) employing a welting agent such as paraffin, ib) thoroughly mixing the said mixture and compatibilizer and reinforcing agent optionally adding polyamide, (c) subjecting the mixture so obtained to melt extrusion to get the polymeric composition in form of chips, and converting to desired articles, such as herein described, bv conventional methods if so desired. 12 process as claimed in claim 11 wherein the polymeric blend in step (a) is prepared by compounding UV light susceptible polymeric component and a biodegradable polymer by melt extrusion, then adding the compounded product to low density olefin selected from low density polyethylene (LDPE). 13 A process as claimed in claim llwherein the polymeric blend in step (a) is prepared by compounding UV light susceptible polymeric component, a biodegradable polymer, and low density olefin selected from low density polyethylene (LDPE) by melt extrusion in presence of wetting agent light paraffin oil. 14 A process as claimed in claims 11 to 13 wherein UV light susceptible polymeric component is polypropylene, a biodegradable polymer is poly saccharide, low density olefin is low density polyethylene (LDPE), and wetting agent is light paraffin oil. 15. A process as claimed in claim 10 wherein the compatibilizer used is copolymer containing maleic anhydride as one of the monomer having 0.2 to 10% of maleic anhydride by wt of copolymer preferably polyethylene - co-ethyl acrylate-co-maleic anhydride (EM) or copolymer of styrene maleic anhydride, butyl acrylate, 2-ethylhexyl arcylate and methacrylic acid and reinforcing agent selected from polymer capable of swelling used is clay of smectite group, preferably clay that is treated with oxidizing agent after successive sieving. 16 A degradable polymeric composition a process therefore and the products thereof substantially as herein described with reference to the examples and drawings.

Full Text

This invention relates to a degradable polymeric composition, a process therefore and products thereof.
FIELD OF INVENTION:
The invention particularly relates to a polymeric composition that is photo degradable as well as biodegradable. Further the invention relates to a multicomponent composition. The invention also provides a process for the preparation of the title product. The process according to the present invention employs readily available components. The process is simple to operate commercially feasible and cost effective. The invention also claims the products such as plastic films, containers packaging material involving the polymeric composition of the present invention particularly when prepared by the process of this invention. The products thus prepared have improved thermal sealing properties and superior mechanical properties. The products are suitable for using at low or subzero level temperatures
BACKGROUND OF THE INVENTION:
Plastics are used extensively in almost every field. Among the various applications, plastics are used mostly in packaging. The use of plastics has given rise to improved methods of packaging goods. For example, polyethylene and polypropylene plastic films, bags, bottles, Styrofoam cups, blister packages, and the like provide stable, relatively unbreakable, chemically resistant lightweight packaging. With the wide acceptance of thermoplastic articles the market size of plastic has grown to over 150 million tones and is expected to double by 2010. A reference can be made to USP 0040062884, Economic Times Polymer, June - July 2005. Plastics have also found wide spread use in other disposable products such as, for example, disposable personal care products such as diapers, disposable work tools/ instruments/garments, and other disposable garments. Though many advantages of plastics have lead to their increased usage in a variety of products, the increased usage, however, has resulted in accumulation of huge amount of solid waste, since the plastic must be disposed of after it is used and thereby has created a serious environmental problem. As a result of the stability and durability of plastics, however, they tend to remain in our environment for a long time, without decomposing after disposal. It has been estimated that over 50

percent of the annual tonnage of all manufactured synthetic polymers are applied as packaging materials and that 90 percent of this ends up as a component of urban garbage. It has also been estimated that recalcitrant plastic accumulates in our environment at a rate of 25 million tons per year.
Burning of plastics is an unsatisfactory disposal solution, since this tends to discharge smoke that adds to air pollution and destruction of the ozone layer. Burial in a waste site is also not an effective means of disposal. Composting is also not advisable due to non-degradable nature of the plastics. Thus Landfill was the only adoptable disposal method. However, accumulation of plastics in our environment has tended to result in landfills becoming filled to capacity; unsightly litter destroying the scenery and landscape; and destruction of the living environment for marine life and other forms of life in turn impairing ecosystem as a whole.
In an effort to resolve the environmental problem, several techniques have been adopted to attribute the degradable characteristics to the polymer. The need is further enhanced due to decreasing landfill space. The problem can also be solved by incorporating additives in certain ways with the polymeric compositions used to make plastics to increase the rate at which the plastic is degraded to environmentally friendly compounds. These additives, commonly called degradants, increase the rate of degradation of the plastic. The degradation could be photodegradation, biological degradation, and/or chemical degradation. However, blending of the degradants with the virgin polymer affects the other properties of the plastics such as mechanical strength and resistance to moisture.
The existing art known to the inventor includes US Patent No. US2002028857. In accordance with this patent, there have been over 500 patents in the last thirty years. Yet none of these patents has led to products which have been successful in establishing appreciable markets in the overall plastics market due to following reasons:
1) the articles lacked sufficient strength, 2) the articles had poor shelf life, 3) the articles were too expensive, and/or 4) fabrication into a useful article was difficult.
The invention relates to biodegradable and/or compostable polymeric composition in the form of hollow/filled isotropically oriented plastic microspheres with potential use for forming films, coatings, fibers, molded articles or thermoformed articles.

US 200202885, US5,397,759, and US 5,225,230 also relate to compostable Biodegradable polymeric composition in form of micro-spheres that involve multistage process.
Us Patent No. 5,334,520 related to Id's 'BIOPOL' advocates using po!y-beta-hydroxybutyrate (PHB) and polyhydroxyvalerate for the preparation degradable plastics. The patent claims to achieve advantage over the prior art disclosing employing genetically modified Escherichia coli (E. coli) by eliminating the stringent process and operational conditions. However, despite PHB's advantages over other materials, its high cost of production has hindered its performance in the market
U.S. Pat. No. 3,840,512 discloses thermoplastic compositions containing a metal salt of a fatty acid and a free carboxylic acid. Compression molded films which included both the metal salt of a fatty acid and a free carboxylic acid exhibited shorter times before the film became embrittled when exposed to light than films containing only the metal prodegradant.
U.S. Pat No. 3,941,759 discloses a degradable plastic containing an organic photo-sensitizer and at least one organic derivative of a transition metal. Degradation is initiated by a photo-oxidative reaction of the photosensitizer and is sustained by the organic derivative of a transition metal. The plastic will continue to oxidize in the dark after an initial exposure to ultraviolet light.
U.S. Pat. No. 3,994,855 discloses thermoplastic polymers or copolymers of .alpha.-olefins containing one or more transition metals. The polymer compositions are degraded under the action of sunlight and/or ultraviolet light and may also be subject to thermal degradation.
U.S. Pat. No. 4,101,720 discloses a degradable plastic composition that includes an organic polymeric material having dispersed therein at least one organic derivative of a transition metal and at least one readily autoxidizable organic material.
U.S. Pat. No. 4,156,666 discloses a degradable polyolefin resin comprising a polyolefin, a fatty acid or ester of a fatty acid and a monohydric aliphatic alcohol, and

optionally an inorganic filler. The resins are molding resins and degrade when subjected to sunlight.
U.S. Pat. No. 4,256,851 discloses a degradable plastic composition comprising an organic polymeric material having dispersed therein at least one ethylenically unsaturated alcohol or ethylenically unsaturated ester derived therefrom as a readily autoxidizable substance.
U.S. Pat. No. 4,360,606 discloses a plastic composition containing an organic photosensitizer and at least one readily autoxidizable organic substance. Exposure of the polymeric material to an artificial source of light or sunlight initiates a chemical degradation process. The initial photochemical reaction is followed by susbequent reactions that are essentially thermal (i.e., non-photochemical). The readily autoxidizable substance accelerates the thermal autoxidation step that follows the initial photochemical step.
U.S. Pat. No. 4,461,853 discloses a controllably degradable vinyl polymer composition that contains a complex of two different metals. A combination of iron and nickel compounds provides enhanced photodegradation of the polymer composition.
U.S. Pat. No. 4,476,255 discloses a plastic composition containing a photosensitizer. Exposure of the plastic composition to natural sunlight or artificial sources of ultraviolet light initiates degradation of the composition.
U.S. Pat. No. 4,517,318 discloses a photodegradable styrene resin that comprises a styrene resin and at least one photodegradable agent selected from benzophenone, anthroquinone, fluorene, xanthone, phenylalkyl ketones, phenacyl halides, and derivatives of these compounds and optionally at least one photodegradable accelerator.
U.S. Pat. No. 4,931,488 discloses thermoplastic polymer compositions that include a biodegradable substance, such as starch; a transition metal compound; and a fatty acid or ester of a fatty acid. The compositions may further include one or more other transition metal compounds to catalyze degradation of the polymer. The polymer compositions are degraded under the action of heat and/or ultraviolet light.

U.S. Pat. No. 4,983,645 discloses that the addition of camphorquinone to polyethylene accelerates the photodegradation of the polymer when the polymer is exposed to ultraviolet light.
U.S. Pat. No. 5,091,262 discloses a biodegradable multilayer polyethylene film produced by a conventional extrusion process. The inner layer of the film contains about 3 to 40 percent starch and the exterior layers comprise polyethylene and at least one prodegradant to facilitate degradation of the outer layers and expose the starch filled inner layers. However, the disadvantage attached with the starch based products is that the products are weak brittle and have short shelf life. Particularly the products loose strength when stored under tropical conditions.
U.S. Pat. No. 5,096,939 discloses a polymeric composition with enhanced reactivity toward oxidative and/or photo-oxidative degradation. The rate of degradation is enhanced by incorporating at least one alkoxylated ethylenically unsaturated compound as an organic photosensitizer. The compositions may further include other readily oxidizable substances.
U.S. Pat. No. 5,134,193 discloses a polyethylene copolymer modified to contain chromomorphic moieties, which absorb at wavelengths greater than 200 nm, such as para-substituted benzenes and anthracenes, chemically bonded thereto. The copolymer, when added to virgin polyethylene renders the composition more susceptible to ultraviolet radiation.
U.S. Pat. No. 5,145,779 discloses a process for degrading €2 to Cg alpha olefin starch containing polymers with lignin degrading microorganisms.
Us Pat. No. 5,281,681 describes a process for degradable polymer having ester group inserted in the backbone of polyethylene. The product is low molecular weight product. However, the process has to be performed at very temperature and pressure.

The Chinese Patent number 95191396 reports a polymer such as microorganism polyester, aliphatic polyester, and Polylactic acid that attributes photo and/or biodegradable property to the product. The technology is very expensive. U.S. Pat. No. 5,258,422 discloses compostable and biodegradable thermoplastic compositions comprising a thermoplastic polymer, a hydrolytically unstable antioxidant, a pro-oxidant, an accelerator, and a property modifier.
U.S. Pat. No. 5,308,906 discloses an extrudable elastomeric composition composed of an elastomer A-B-A' block copolymer, where A and A' are each a thermoplastic polymer endblock and B is a conjugated diene monomer having a low degree of residual ethylenic unsaturation, a polyolefin, and an effective amount of transition metal compound distributed in the blend of the polyolefin and block copolymer. The elastomeric composition degrades in thermally oxidative environments.
U.S. Pat. No. 5,378,738 discloses a biodegradable plastic produced by adding a substance that imparts a hydrophilic property to the plastic so that the plastic is decomposed by Blasidomycetes.
U.S. Pat. No. 5,444,107 discloses a degradable polymer composition consisting essentially of a thermoplastic polymer composition comprising primarily polylactic acid or a copolymer of lactic acid and another hydroxy-carboxylic acid and starch and/or modified starch. The degradation rate of the polymer composition is controlled by the varying the amount of starch and/or modified starch.
U.S. Pat. No. 5,461,093 discloses a biodegradable polyethylene composition. The composition includes starch chemically bonding to polyethylene with a coupling agent, a radical initiator, a Lewis acid, an autooxidizing agent, and a plasticizer.
U.S. Pat. No. 5,565,503 discloses a film of a biodegradable polyolefin resin. The resin contains fillers selected from the group including inorganic carbonate, synthetic carbonates, nepheline syenite, magnesium hydroxide, aluminum trihydrate, diatamaceous earth, mica, natural or synthetic silicas, calcined clay, or mixtures thereof and a metal carboxylate as a prodegradant.

U.S. Pat. No. 5,854,304 discloses a chemically degradable/compostable additive package or concentrate that is added to polyolefins. The additive package is a combination of a metal carboxylate and an aliphatic poly hydroxy-carboxyl acid.
U.S. Pat. No. 5,861,461 discloses a biodegradable plastic composition characterized in that a thermoplastic modified starch is chemically bonded by the use of a coupling agent to a matrix resin of polyethylene and a biodegradable polyester.
U.S. Pat. No. 5,866,634 discloses a biodegradable polymer composition comprising polylactic acid mixed with a polyester type biodegradable polymer.
U.S. Pat. No. 5,973,024 discloses a biodegradable plastic composition and a method for controlling the rate of biodegradation of the biodegradable plastic. The rate of degradation is controlled by adding a carbodiimide compound to the biodegradable plastic. The carbodiimide is mixed into the plastic by dissolving the plastic and carbodiimide in an organic solvent and then removing the organic solvent by distillation or by mixing the carbodiimide with the plastic by melt-kneading.
WO 88/09354 discloses a degradable polymer composition that is a blend of a normally stable chemically saturated polymer and a less stable chemically unsaturated polymer or copolymer, an anti-oxidant active over a limited period of time, and a latent pro-oxidant, such as an organic salt of a transition metal.
WO 92/11298 discloses a photodegradable thermoplastic composition that includes a first transition metal compound, a second transition metal compound, and an aromatic ketone. The second transition metal compound acts as a catalyst with the first transition metal compound to enhance degradation of the thermoplastic material. The aromatic ketone has a synergistic effect that increases photodegradation of the plastic.
WO 94/13735 discloses a degradable thermoplastic compositions. The compositions include a thermoplastic polymer component combined with a directly biodegradable component, an oxidizable component, transition metal additives, and an aromatic ketone. The polymeric material degrades in three stages. The first stage is biological

removal of the directly biodegradable component which results in mass reduction and a highly porous material. The second stage is chemical and results in oxidative shortening of the long polymer chains to decrease their molecular weight and the third stage involves biological metabolism of the low molecular weight fragments. The process is cost extensive and cumbersome.
US Pat. No. 6,482,872 also teaches incorporation of degradants selected from (i) photodegradant comprises one or more of aliphatic or aromatic ketones, quinones, peroxides, hydroperoxides, azo compounds, organic dyes, latent sensitizers, aromatic hydrocarbons, or mixtures thereof; (ii) biodegradant comprises one or more of chitin, starch, cellulose, glucose derivatives, polysaccharides, poly-.beta.-hydroxybutylate, poly caprolactone, polyesters, carbodiimides, or mixtures thereof; and (iii) chemical degradant comprises one or more of a combination of a metal carboxylate and an aliphatic poly hydroxy-carboxyl acid, a combination of metal carboxylate and filler, or a transition metal complex. The degradants are generally added polymer immediately after the polymer is synthesized and while the polymer is still fluid to ensure proper homogeneous blend to overcome the drawbacks of the prior art that advocates addition of degradants to virgin polymer compositions by melting the virgin polymer or by master batching there by achieving cost effective technology with enhanced efficacy.
US2004062884 relates to a multicomponent composition for photodegradable and biodegradable plastic articles, avoiding employing starch. The composition discloses using new bioactive material of chitin, casein and the like, with biodegradable aid component, photodegradable and auto-oxidation catalysis component, and nonmetallic minerals and the like. Under natural condition, the degraded material can be utilized by microorganism to release carbon dioxide and water, and acts as an eco-friendly plastic material. The process is not feasible for commercial purposes as it requires number of costly components in addition to being cumbersome.
US 20050203208 discloses mineral filled polyester resin based degradable polymeric composition containing 10 to 50 wt % fillers. The fillers are selected from two different groups: the first consisting of block type fillers including inorganic carbonates, synthetic carbonates, feldspar, nepheline syenite, magnesium oxide, magnesium hydroxide, aluminum trihydrate, and diatomaceous earth; the second consisting of platy

fillers including talc, mica, or calcined clays, all having a particle size less than 150 mesh.
As can be seen from the herein above disclosure the prior art suffers from one or the other problems making it commercially unfeasible. The main drawbacks are : lack of adequate strength, poor shelf life, cost extensive, and/or require sophisticated infrastructure and stringent operational conditions.
Thus there felt an imperative need for a degradable polymeric composition which is cost effective, easy to operate, technically and commercially viable, eco-friendly, having desired mechanical properties, extended shelf life and makes use of easily and abundantly available ingredients.
After continuous and painstaking R & D work the inventors have arrived at a degradable polymeric composition employing high and low density olefins, saccharides, swellable polymer degradant in judicious manner. It is not possible to arrive at this composition without extensive human intervention and conducting extensive experiments. The prior art fails to give conclusive indication for arriving at the composition of this invention, which can have desired flexibility, shelflife, ability to use at varied temperature and complete degradation to minerals through photo and biodegradation.
The novelty resides in making a functional polymeric blend, that is photodegradable as well as bio-degradable, into a packaging polymer using unique combination of ingredients particularly modified compatibilizer. The added advantage is that the polymer of the present invention is functional at subzero temperature.
SUMMARY OF THE INVENTION:
The main object of this invention is to provide a degradable polymeric composition
avoiding if not eliminating completely the shortcomings of the existing processes.
Other objective of the invention is to provide a polymeric multicomponent composition having improved mechanical properties and shelf life.
Another object of this invention is to provide a degradable polymeric composition that is photo as well as biodegradable resulting in to minerilazation.

Yet other object of this invention is to provide a degradable polymeric composition prepared using easily available ingredients.
Yet another object of this invention is to provide a degradable polymeric composition comprising high molecular weight polymeric components, compatibilizer, and reinforcing agent.
Still other object of this invention is to provide degradable polymeric composition useful for preparing packaging articles and packaging films particularly with improved thermal sealing property. Further, the articles prepared by using the composition of the present invention can be used effectively while maintaining its mechanical properties even at sub zero degree Celsius conditions.
Still another object of this invention is to provide a process for preparing degradable polymeric composition, the title product of the present invention as defined herein above.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.
The term biodegradation means a process of degradation accomplished with microbial activity. The term photo degradation indicates the degradation taking place due to exposure to light either natural or artificial.
STATEMENT OF INVENTION:
Accordingly the present invention provides a degradable polymeric composition
comprising of the following components by weight based on the total weight of the
composition:

(i) 0.2 to 10% by wt. compatibilizer cum cation exchanging agent,
(ii) 0.0 to 10% by wt. reinforcing agent selected from water-swellable polymer,
(iii) 0.0 to 20% by wt. polyamide and balance
(iv) a polymeric blend such as herein described,
A polymeric composition as claimed in claim 1 is photodegrable as well as biodegradable.
According to one of the embodiment of this invention the polymeric blend comprising
(a) 5 to 45 % UV light susceptible polymeric component having crystallanity in the
range of 40% to 70%, (b) 5 to 30% biodegradable polymer of natural origin, and (c) 40
to 80% by wt of low density olefin capable of imparting desired mechanical properties
and having crystallanity in the range of 40% to 90%.
In one of the embodiments of the present invention UV light susceptible polymeric
component having crystallanity in the range of 40% to 70% used may be such as
polypropylene.
According to other embodiment of the present invention biodegradable polymer of
naturel origin used may be such as saccharide preferably polysaccharide.
According to other embodiment of the present invention the low density polyolefin used may be low density polyethylene
According to another embodiment of the present invention the compatibilizer used may be such as copolymer containing maleic anhydride as one of the monomer having 0.2 to 10 % of maleic anhydride by wt of copolymer.
According to yet other embodiment of the present invention the low density olefin capable of imparting desired mechanical properties and having crystallanity in the range of 40% to 90% used may be low density polyethylene.
According to yet another embodiment of the present invention the reinforcing agent capable of swelling may be such as clay of smectite group, preferably clay that is treated with oxidizing agent after successive sieving.

The polyamide used may be such as nylon, preferably having crystallanity in the range of 40% to 60%.
The polymeric composition of the present invention preferably comprisiing of the following components by weight based on the total weight of the composition:
(a) 5 to 45 % Polypropylene,
(b) 5 to 30 % polysaccharide,
(c) 40 to 80 % low density polyethylene (LDPE),
(d) 0.2 to 10 % co-polymer containing maleic anhydride as one of the monomers,
(e) 0.2 to 10 % modified smectite clay, and
(f) 1.0 to 20 % polyamide (nylon-6)
In accordance with the other aspect of this invention there is provided a process for preparing the degradable polymeric composition comprising of steps:
(a) preparing a polymeric blend by mixing thoroughly UV light susceptible
polymeric component having crystallanity in the range of 40% to 70%, a
biodegradable polymer of natural origin, and a low density olefin optionally
employing a wetting agent such as paraffin,
(b) thoroughly mixing the said mixture and compatibilizer and reinforcing agent
optionally adding polyamide,
(c) subjecting the mixture so obtained to melt extrusion to get the polymeric
composition in form of chips, and converting to desired article by conventional
methods if so desired.
The polymeric blend in step (a) may be prepared by compounding UV light susceptible polymeric component and a biodegradable polymer by melt extrusion, then adding the compounded product to low density olefin selected from low density polyethylene (LDPE).
DETAILED DESCRIPTION:
In the present invention polypropylene a UV susceptible olefin is blended with polysaccharide preferably modified polysaccharide and then the blend so obtained

is mixed with polyethylene to obtain polymeric composition useful for preparing a photo as well as biodegradable plastic articles such as films, molded material/containers, and fibres. It may be worthwhile to mention here that though polypropylene and polyethylene are of polyolefin origin, pose problems in forming homogeneous mixture due to difference in crystallanity and other microstructure the two components. The presence of methyl group attached to alternate carbon atoms on the chain backbone of polypropylene is responsible in altering the properties of polypropylene. A reference can be made to an article by J.A. Brydson, Plastic materials, fifth edition, Butterworth, 1989, p.237.
In the present invention a copolymer containing maleic anhydrideas one of the monomers has been employed as compatibilizer. This co-polymer facilitates the blending of polypropylene and polyethylene. Additionally the said copolymer also acts as cation exchange agent for smectite clay used as reinforcing agent. Smectite clay is known for its swelling property when contacted with water. It is known to be of expanding lattice type in which polymeric component can be reacted or accommodated. The group of clay can be easily modified by a compound capable of exchanging cations and thus can be incorporated in the polymeric matrix without any hiderence. The clay employed in the present invention is modified to a nano clay by successive sieving and chemically treating with oxidizing agent selected from hydrochloride, peracetic acid, perchloric acid, or hydrogen peroxide. The structural details of the modified clay is a subject matter of Indian Patent application No. 1354/DEL/2005 and is incorporated in entirety by way of reference in this application.
Polyamide helps improving physical properties whenever incorporated. The composition is prepared as detailed herein above.
Physical mixture of degradable polymer and polymer susceptible to UV light is compounded by melt extrusion in a twin extruder. The polymeric bio-photo degradable composition is thus made in the form of compounded cylindrical chips of about 2 to 3mm diameter and 2 to 4 mm length. The chips are then added to LDPE in a polyethylene bag/container and tumbling it thoroughly before putting in to extruder. This mixing may be made more uniform by addition of small quantity of light paraffin oil say 0.1 to 0.5 % by weight of the total weight of chips and LDPE granules. Compatibilizer and reinforcing agent are then added and the contents are again tumbled to ensure proper mixing. The pre wettings of chips by

paraffin oil helps in proper adherence of powdery particles of the compatibilizer and reinforcing agent and thereby ensure uniform mixing. Twin extruder used for melt extrusion may be co-rotating or counter-rotating type. Blown films were made using the compounded chips in a blown film machine having seven heating zones of graded temperature between 100 to 230°C.
Alternately the polymeric blend comprising of degradable polymer, polymer susceptible to UV light and LDPE is taken in a polyethylene bag/container and tumbling it thoroughly in presence of of small quantity of light paraffin oil say 0.1 to 0.5 % by weight of the total weight of chips and LDPE granules. Compatibilizer and reinforcing agent are then added and the contents are again tumbled to ensure proper mixing. The pre wettings of chips by paraffin oil helps in proper adherence of powdery particles of the compatibilizer and reinforcing agent and thereby ensure uniform mixing. The composition thus obtained is compounded by melt extrusion in a twin extruder. The polymeric bio-photo degradable composition is thus made in the form of compounded cylindrical chips of about 2 to 3mm diameter and 2 to 4 mm length.
Twin extruder used for melt extrusion may be co-rotating or counter-rotating type. Blown films were made using the compounded chips in a blown film machine having seven heating zones of graded temperature between 100 to 230°C. The invention is further illustrated with the examples. However, these are purely for the purpose of illustration should not construe, in any way, the scope of protection intended to seek.
EXAMPLE 1:
0.32 kg polypropylene (PP) (MFI - 0.7g/10min) and 0.48 kg polysaccharide were taken in a polyethylene bag of 5 kg capacity. The content was then melt extruded in a co-rotating extruder keeping the temperature of the final melt at 240°C. The chips thus prepared were then missed with 2.88 kg LDPE (MFI- 0.9 g/lOmin). 40g polyethylene - co-ethyl acrylate-co-maleic anhydride (EM) having melting point 92 °C , and maleic anhydride content of 3%by wt of polymer, and 32g clay were then added to the content and mixed thoroughly. The mixture was then melt- extruded

in a co-rotating extruder while maintaining final temperature of the final melt at
230°C.
EXAMPLE 2:
2.72 kg LDPE (MFI- 0.9 g/lOmin) 0,48 kg PP and 0.48 kg polysaccharide were taken in a polyethylene bag of 5 kg capacity. 6g of light paraffin oil was added to the content and tumbled to have proper mixing. 40g polyethylene - co-ethyl acrylate-co-maleic anhydride (EM) having melting point 92°C , and maleic anhydride content of 3%by wt of polymer, and 32g clay were then added to the content and mixed thoroughly. The mixture was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C.
EXAMPLE 3 & 4:
A polymeric composition was made using components and the process as described in Example 1 and 2 except that 25g of copolymer of styrene maleic anhydride, butyl acrylate, 2-ethylhexyl arcylate and methacrylic acid containing 28% maleic anhydride (SM) by wt. and having MP 185°Cwas employed as compatabilizer a in place of EM. Further the compositions were made with or without adding clay. The mixture was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C.
EXAMPLE 5:
A polymeric composition was made using components and the process as described in Example 3 except change in the quantity of LDPE, PP, and polysaccharide used that was 2.88 kg, 0.32 kg, and 0.32 kg respectively.
EXAMPLE 6:
0.32 kg PP (MFI 0.7g/10min), 2.50 kg LDPE (MFI 0.9g/10 min.), and 0.32 kg poly saccharide and 0.32 kg polyamide (nylon 6 having MP 215°C) were taken in taken
in a nr»1v*»th\/1*»np haa rtf f\ \ca ranar.itv and f\a nf lioht naraffin nil was added

tumbled to have proper mixing. 40.0 g of SM (compatibilizer) and 25 g of clay were added and mixed thoroughly. The content then was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C.
EXAMPLE 7:
0.32 kg PP (MFI 0.7g/10min), 2.50 kg LDPE (MFI 0.9g/10 min.), and 0.32 kg poly saccharide and 0.32 kg polyamide (nylon 6 having MP 215°C) were taken in taken in a polyethylene bag of 6 kg capacity and 6g of light paraffin oil was added tumbled to have proper mixing. 40.0 g of SM (compatibilizer) was added and mixed thoroughly. No clay was added. The content then was then melt- extruded in a co-rotating extruder while maintaining final temperature of the final melt at 230°C.
Raman spectra of films prepared in accordance with Examples 3 & 4 are shown in figures 1 and 2 accompanying this specification. The spectra show the corresponding standard Raman shifts for each components.
The following tables show the properties of the products prepared using polymeric composition of this invention. Table 1 shows the tensile strength of the films prepared from the polymeric composition of Examples 3,4, 6, and 7.
TABLE 1

(Table Remove)

Table 2 shows the tensile data of film 3 and 4 after exposure to solar radiations at an altitude of 26° 13' N and a latitude of 78° 13'E during Nov. -Jan. for 30 days and 45 days.
TABLE 2

(Table Remove)

It may be worthwhile to mention here that though the polymer prepared without employing clay is effective and has phtodegradability and biodegradability to the extent of 50% and 31% respectively, addition of clay enhances the same to the tune of 60% and 40% respectively. Any variations in the proportions as obvious to the person skilled in the art may be encompassed in the ambit of the protection sought in this application

WE CLAIM:
1. A degradable polymeric composition comprising of the following components
by weight based on the total weight of the composition:
(i) 0.2 to 10% by wt. compatibilizer cum cat ion exchanging agent,
(ii) 0.0 to 10% by wt. reinforcing agent selected from water-swellable
polymer,
(iii) 0.0 to 20% by wt. polyamide and balance (iv) polymeric blend such as herein described.
2. A polymeric composition as claimed in claim 1 is photodegrable as well as
biodegradable.
3. A polymeric composition as claimed in claims 1 and 2 wherein the polymeric
blend comprising (a) 5 to 45 % UV light susceptible polymeric component
having crystallanity in the range of 40% to 70%, (b) 5 to 30% biodegradable
polymer of natural origin, and (c) 40 to 80% by wt of low density olefm capable
of imparting desired mechanical properties and having crystallanity in the range
of 40% to 90%.
4. A polymeric composition as claimed in claims 1 to 3 wherein the UV light
susceptible polymeric component having crystallanity in the range of 40% to
70% used is polypropylene.
5. A polymeric composition as claimed in claims 1 to 3 wherein the biodegradable
polymer used is saccharide preferably polysaccharide.
6. A polymeric composition as claimed in claims 1 to 3 wherein the low density
polyolefm capable of imparting desired mechanical properties and having
crystallanity in the range of 40% to 90% used is polyethylene
7. A polymeric composition as claimed in claim 1 wherein the compatibilizer used
is copolymer containing maleic anhydride as one of the monomer having 0.2 to
10% of maleic anhydride by wt of copolymer preferably polyethylene- co-ethyl

acrylatc-co-maleic anhydride (\;.M) or copolymer of styrene maleic anhydride, butyl acrylale, 2-ethylhcxyl arcylate and methacrylic acid.
8, A polymeric composition as claimed in claim 1 wherein the reinforcing agent
selected from poKmci capable of swelling used is clay of smectite group,
preferably clay that is treated with oxidizing agent after successive sieving.
A polymeric composition as claimed in claim 1 wherein the polyamide used is nylon, preferably the one having crystallanity in the range of 40% to 60%.
9. A polymeric composition as claimed in claim 1 comprisiing of the following
components by weigh! based on the total weight of the composition:
(a) 5 to 4.5 % Polypropylene,
(b) 5 to 30 "/» polysaccharide,
80 % Sow density polyethylene (LDPE),
(d) 0.2 to 10 % co-polymer containing maleic anhydride as one of the
monomers,,
<:e to modified smectite clay and polyamide> 11. A process ior preparing the degradable polymeric composition comprising of steps:
(a) preparing a polymeric blend by mixing thoroughly UV light susceptible polymeric component having crystallanity in the range of 40% to 70%, a biodegradable polymer of natural origin, and a low density olefin optional!) employing a welting agent such as paraffin, ib) thoroughly mixing the said mixture and compatibilizer and reinforcing agent optionally adding polyamide,
(c) subjecting the mixture so obtained to melt extrusion to get the polymeric
composition in form of chips, and converting to desired articles, such as
herein described, bv conventional methods if so desired.

12 process as claimed in claim 11 wherein the polymeric blend in step (a) is
prepared by compounding UV light susceptible polymeric component and a
biodegradable polymer by melt extrusion, then adding the compounded product
to low density olefin selected from low density polyethylene (LDPE).
13 A process as claimed in claim llwherein the polymeric blend in step (a) is
prepared by compounding UV light susceptible polymeric component, a
biodegradable polymer, and low density olefin selected from low density
polyethylene (LDPE) by melt extrusion in presence of wetting agent light
paraffin oil.
14 A process as claimed in claims 11 to 13 wherein UV light susceptible polymeric
component is polypropylene, a biodegradable polymer is poly saccharide, low
density olefin is low density polyethylene (LDPE), and wetting agent is light
paraffin oil.
15. A process as claimed in claim 10 wherein the compatibilizer used is copolymer containing maleic anhydride as one of the monomer having 0.2 to 10% of maleic anhydride by wt of copolymer preferably polyethylene - co-ethyl acrylate-co-maleic anhydride (EM) or copolymer of styrene maleic anhydride, butyl acrylate, 2-ethylhexyl arcylate and methacrylic acid and reinforcing agent selected from polymer capable of swelling used is clay of smectite group, preferably clay that is treated with oxidizing agent after successive sieving.
16 A degradable polymeric composition a process therefore and the products thereof substantially as herein described with reference to the examples and drawings.

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Patent Number

279434

Indian Patent Application Number

2201/DEL/2006

PG Journal Number

04/2017

Publication Date

27-Jan-2017

Grant Date

22-Jan-2017

Date of Filing

06-Oct-2006

Name of Patentee

DIRECTOR GENERAL, DEFENCE RESEARCH&DEVELOPMENT ORGANISATION, MINISTRY OF DEFENCE

Applicant Address

ER&IPR, IPR GROUP, ROOM NO 348 B-WING, DRDO BHAWAN RAJAJI MARG NEW DELHI-110011

Inventors:

#	Inventor's Name	Inventor's Address
1	SINGH LOKENDRA	DRDE, JHANSI ROAD GWALIOR
2	CHAUHAN RAM SINGH	DRDE JHANSI ROAD, GWALIOR
3	SEKHAR KRISHNAMURTHY	DRDE JHANSI ROAD, GWALIOR
4	RAHMAN MOHD SAFIKUR	DRDE JHANSI ROAD, GWALIOR
5	GHARIA MAHENDRASINH	DRDE JHANSI ROAD, GWALIOR

PCT International Classification Number

C067C

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA