DESC:FIELD OF INVENTION:
The present invention relates to a plastic composition which is biodegradable, and which does not discharge contaminants during incineration or leave plastic fragments after decomposition. The present invention further relates to a method of fertilising the soil through the composed plastic resulting in growth of plants.

SUMMARY OF INVENTION:
The present invention is to provide a plastic composition which is biodegradable, and which does not discharge contaminants during incineration. A further main objective of the present invention is post composition use of these biodegradable plastic which shall result in fertilization of soil.

BACKGROUND OF THE INVENTION
In recent years, increase in plastic waste has become a great social problem. Since many of polymeric materials have hitherto been developed and produced in search of high performance and long-term stability, they are not easily decomposed in a natural environment. Therefore, how to dispose and manage a large quantity of plastic waste which has become useless becomes a social problem on a world-wide scale. Of the plastic waste, hollow containers formed from a variety of synthetic resins, such as polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate (PET), and polyvinyl chloride resins become a special problem because they are bulky.

Under the circumstances, biodegradable polymers, which are degraded by natural microorganisms, attract attention as polymeric a material which impose no burden on the environment and also helps in providing essential supplements in the growth of plants. The biodegradability can be evaluated by, for example, a degradability test in soil (soil degradability test).

DETAILED DESCRIPTION:

Plastics have become an indispensable part our society due to their wide range of uses, relative light weight, and low cost. Plastics include any of a wide range of synthetic or semi-synthetic organic solids that are mouldable. Plastics are typically organic polymers of high molecular mass. They are usually synthetic, most commonly derived from petrochemicals. However, their ubiquity has also come with problems. Their stability makes disposal of plastic products a problem. They often litter the landscape for years due to their stability. Two divergent approaches have been employed to attempt to solve the problem, namely recycling and biodegradable additives.

Plastic recycling is the process of recovering scrap or waste plastic and reprocessing the material into useful products, sometimes completely different in form from their original state. For instance, this could mean melting down soft drink bottles and then moulding them as plastic chairs and tables. Typically a plastic is not recycled into the same type of plastic. Even during the typical recycling process, when different types of plastics are melted together, they tend to phase-separate and settle in layers. The phase boundaries cause structural weakness in the resulting material, meaning that polymer blends are useful in only limited applications.

The second approach is biodegradable additives. Biodegradable plastics are plastics that are capable of being decomposed by bacteria or other living organisms. Two basic classes of biodegradable plastics exist: bioplastics, whose components are derived from renewable raw materials and plastics made from petrochemicals with biodegradable additives which enhance biodegradation.

Numerous attempts have been made to produce degradable films from petroleum and cellulose-derived materials but none has been completely successful, apparently because they were too costly, or they decompose too slowly for many applications. Starch is probably the most abundant, low-cost, biodegradable polymer available and its use in plastic film production would greatly reduce the demand for petrochemicals and the negative impact on the environment now caused by discarding nonbiodegradable films. Since starch alone forms a brittle film that is sensitive to water, and so combined with other materials in order to produce a satisfactory product.

The proposed invention is about a starch-based polymeric material comprising thermoplastic starch formed by converting at least one of native starch or a starch derivative into a thermoplastic starch melt. Thermoplastic starch (30-50%) is blended with biodegradable plastic (25-30%) with the help of grafted maleic anhydride (0.5-1%). To make biodegradable and compostable polymer and to make it plant usable fertilizer NPK (Nitrogen, Phosphorus, Potassium) or/and NPKS (Nitrogen, Phosphorus, Potassium& Sulphur) (20-30%) is mixed with it.

Thus the principal objective of the present invention is to provide a biodegradable product which combines the desirable properties of plastics i.e. Strength, ease of forming into desired shapes and resistance to chemical attack with significant biodegradability such that a product buried in the soil will degrade to destruction typically in few months. Thus products in accordance with the invention will make a significant contribution to the environment by reducing the disposal problem caused by chemically inert and bulk plastics.

Composting is a natural process by which organic material is decomposed into humus. Decomposition is principally done by microorganisms. These organisms decompose the organic matter as their food source and provide nutrient to plants. The present invention not only holds the qualitied of a biodegradable plastic but also acts as a compostable plastic as well. In order to make it plant friendly and act as fertilizer post composition, components such as Nitrogen, Phosphorus, Potassium is added in the manufacturing process This help in the growth of plants..
Drawback of Prior Art:
Another approach has been to blend starch with biodegradable polyesters. USA patents 5346936 and 6096809 are examples of the use of starches and polyesters to improve the wet strength of the films. The high content of the polyester increases the overall cost of films made from such blends to the point where they are not commercially viable.

In recent years nano clays have been proposed as polymer additives and USA patent 5747560 discloses the use clay treated with an ammonium or phosphonium complex with nylon. USA patents 6034163 and 6162857 disclose the use of organoclays with polyesters. These polymers are not claimed to be biodegradable.

It is an object of this invention to provide a biodegradable polymer which can be processed without difficulty and have acceptable properties for its intended uses and also have a commercially acceptable cost.

Advantage of proposed invention:

1. Biodegradable plastic films/bags are environment friendly and unlike traditional plastics.
2. The proposed invention holds quality of both biodegradable as well as compostable plastic.
3. Low cost in manufacturing which in turn adds a commercial value to it.
4. Proposed bags can be moulded in any size as required.
5. Proposed bags are equivalent to traditional plastic bags in manner to strength and holding capacity.
6. The major essence of the proposed invention is post composition of bags in which acts as a fertilizer for soil.

Thermoplastic starch + Biodegradable plastic
+NPK/NPKS

Forms the raw material of the proposed invention.

Biodegradable films/bags are manufactured in desired size.

Post use such bags can buried in the soil or can be composed
and then mixed with soil.

Post composition these bags acts as a fertilizer and helps
in the growth of plants.
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:-
,CLAIMS:We claim
1. A biodegradable film forming material comprising of:
a. thermoplastic starch (30-50%);
b. biodegradable plastic (25-30%);
c. grafted maleic anhydride (0.5-1%);
d. fertilizer NPK (Nitrogen, Phosphorus, Potassium) or/and NPKS (Nitrogen, Phosphorus, Potassium& Sulphur) (20-30%) is mixed to form the composition.
2. The starch-based polymeric material as claimed in claim 1, wherein biodegradable polymer with added fertilizer can be processed to make articles by using various processes like blown, extrusion, sheet extrusion, & thermoforming etc. for manufacturing of different products.
3. The starch-based polymeric material as defined in claim 2, wherein the film or blown film can be made in mono-layer, co-layer and multi layers of 3, 5, 7 and so on laminate composites also.
4. The starch-based polymeric material as defined in claim 2, wherein these articles can be used in packaging or disposable articles for industrial, agriculture, household purposes and can be in various forms as per the requirement.
5. The starch-based polymeric material as defined in claim 3, wherein user will put the articles made from this material in to the soil, as whole or after the shredded articles will be degraded and converted into fertilizer over a period of time making it suitable for growing plants.