FIELD OF THE INVENTION
The field of invention pertains to a biodegradable plastic. More specifically it pertains to a biodegradable plastic produced using starch from a non-edible source (Tamarind seed) and its method of production thereof. 5
BACKGROUND OF THE INVENTION
Plastic is a polymer composed of synthetic or semi-synthetic polymers (most commonly petrochemicals). Plastics do not exist in nature and are not bio-degradable. They cause pollution of the natural environment by contaminating areas and affecting animal life. However, owing to 10 low-cost and convenience, plastics have become a part of modern life. Most conventional plastics such as polyethylene, polypropylene, polystyrene, poly (vinyl chloride) and poly (ethylene terephthalate) are non-biodegradable and their increasing accumulation in the environment is a threat to the planet.
Problems associated with plastics-The main problem associated with synthetic plastic is its 15 degradation- it pollutes the soil and water environment for years. There are several methods proposed till now for the degradation of synthetic plastics e.g. land fill method, Incineration, recycling etc. However, none of the above methods is suitable for complete degradation. As a result, residues left after improper/incomplete degradation of synthetic plastics act as pollutants and cause several diseases. They remain in environmental cycle and produce harmful effects. 20
Some of the problems associated with plastics are as follows: Harmful effect on environment: Plastics cause climate change as they are not degraded easily they are highly accumulated and led to carbon emission.
i. Health problems: Plastics contain compounds which can leach into drinking water and cause cancer, birth defects, genetic changes, chronic bronchitis, ulcers, skin diseases, 25 deafness, vision failure, indigestion and liver dysfunction etc. over a period of time.
ii. Effect on marine life: Plastic dumped in rivers, sea and other water bodies leads to destruction of marine life and poses a serious hazard to maritime activities including fishing and tourism. Marine life get entangled in plastic debris/waste which affects reproductive
3
output, can cause lacerations, ulcers etc. and in extreme cases lead to death of the marine life also.
Biodegradable Plastics
These are plastics which are made up of biodegradable material or composed of components which 5 are easily degradable in soil or water i.e. biological environment. Hence, these are eco-friendly and provide a promising way to solve drawbacks of petroleum related plastics. Progress in the field has been reviewed in a recent publication (Iwata, T. (2015), Biodegradable and Bio-Based Polymers: Future Prospects of Eco-Friendly Plastics. Angew. Chem. Int. Ed., 54: 3210–3215. doi: 10.1002/anie.201410770). 10
Despite advances, biodegradable plastics suffer from limitations as below:
i. Most of the biodegradable plastics are not fully degradable. They get mixed with regular waste and pose threat to environment.
ii. Biodegradable plastics sometimes behave differently when recycled and thereby cause undesirable effects on human health. 15
iii. Landfilling is used to degrade biodegradable plastics. However, it produces methane which is not desirable because it causes global warming.
Advantages offered by present invention
The present invention discloses a biodegradable plastic made from a non-edible natural polymer i.e. starch from tamarind seeds by a process that is economical and easy. Though various 20 biodegradable plastics are available at present but they are not economical and require cumbersome production strategies. The product of present invention provides a cheap and easy to manufacture biodegradable plastic from a non-edible source i.e. Tamarind seeds. Tamarind is used in a wide range of industries e.g. medicinal and food industry. Seeds of tamarind are discarded as waste. The present invention utilizes this waste raw material to produce starch which is used to 25 make the biodegradable plastic of present invention. Unlike other biodegradable plastics which require the use of PLAs (Poly lactic acid), PLGAs i.e. poly (lactic-co-glycolic acid), PHB
4
(polyhydroxybutyrate) etc. the biodegradable plastic of present invention does not require these acids at all.
Terms and Definitions
1. Plastics: Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organics that are malleable and can be molded into solid objects of diverse shapes. 5 (Reference : https://en.wikipedia.org/wiki/Plastic)
2. Plasticizer: A plasticizer is a substance which when added to a material, usually a plastic, makes it flexible, resilient and easier to handle. Early examples of plasticizers include water to soften clay and oils to plasticize pitch for waterproofing ancient boats. There are more than 300 different types of plasticizers of which about 50-100 are in commercial use. The 10 most commonly used are phthalates and adipates (Reference: http://www.pvc.org/en/p/plasticisers). Glycerol is commonly used as a plasticizer in bioplastics. (Reference: http://green-plastics.net/posts/433/glycerine-bioplastic-it-alternatives-for/)
3. Biodegradation: Biodegradation is nature's way of recycling wastes, or breaking down 15 organic matter into nutrients that can be used by other organisms. "Degradation" means decay, and the "bio-" prefix means that the decay is carried out by a huge assortment of bacteria, fungi, insects, worms, and other organisms that eat dead material and recycle it into new forms. (Reference : http://ei.cornell.edu/biodeg/ )
4. Biodegradable plastic: It is plastic that decomposes naturally within the environment. 20 Degradation is done by microorganisms present in the environment, they metabolize and break down the structure of plastic to be degraded.
5. Tamarind seed (Tamarindus indica): is a leguminous tree in the family Fabaceae indigenous to tropical Africa. The genus Tamarindus is a monotypic taxon, having only a single species. (Reference: https://en.wikipedia.org/wiki/Tamarind) 25
6. Starch: Chemically, Starch is a white, odorless, solid carbohydrate, typically composed of long chains of glucose molecules. It is the most basic form of all carbohydrates, a pure substance, which is insoluble in water. (Reference: http://www.starchfoundation.org/starch.php)
5
7. Vinegar: Vinegar is a liquid consisting mainly of acetic acid (CH3COOH) and water. The acetic acid is produced by the fermentation of ethanol by acetic acid bacteria. (Reference: https://en.wikipedia.org/wiki/Vinegar)
8. Glycerol (C3H8O3): A colorless, odorless, syrupy, sweet liquid, usually obtained by the saponification of natural fats and oils. 5
(Reference: http://dictionary.reference.com/browse/glycerol)
9. Cellulose (C6H10O5)x: A polysaccharide of glucose units that constitutes the chief part of the cell walls of plants, occurs naturally in such fibrous products as cotton and kapok, and is the raw material of many manufactured goods (as paper, rayon, and cellophane).
(Reference: http://www.merriam-webster.com/dictionary/cellulose) 10
10. Gelatin: It is a translucent, colorless, brittle (when dry), flavorless foodstuff, derived from collagen obtained from various animal by-products. It is commonly used as a gelling agent in food, pharmaceuticals, photography, and cosmetic manufacturing.
(Reference: https://en.wikipedia.org/wiki/Gelatin)
PRIOR ART 15
A search of prior art reveals that the product of present invention is novel and not disclosed earlier. A comparison of present invention with relevant prior art patents is given below:
S.No.
Prior Art
Present invention
1.
US20020028857
Discloses thermoplastic compositions which are degradable or compostable comprising polyesteramide
Copolymer (can be starch derivatized with ethyleneimine, cellulose derivatized With ethyleneimine, polysaccharides derivatized With ethyleneimine, lignin derivatized With ethyleneimine), a plasticizer, a cross-linking agent.
The present invention does not disclose a plastic which makes use of that particular plasticizer mentioned in prior art patent or cross-linking agent. Rather plastic of present invention uses glycerol as a plasticizers and starch from non-edible tamarind seeds in addition to vinegar, gelatin, cellulose and glycerol.
6
2.
US 2013/0186303 A1
Discloses bioplastics including an oligosaccharide (obtained by hydrolysis of starch, agar or both), a plasticizer, and an additive (powered clamshell, powdered egg shell, powdered coconut shell, gelatin, saw dust, and combinations thereof).
The present invention does not disclose use of any oligosaccharide, plasticizer and additive cross-linking agent. Rather it comprise use of starch obtained from non-edible tamarind seeds, vinegar, gelatin, cellulose and glycerol.
3.
US20140209841A1
A biodegradable bio-plastic material composition comprising cellulose
based plastics, soy oil based bio plastic, zein (a protein based bio-plastic), protein based bio plastics, starch based plastic, polylactic acid based plastic (PLA), cornstarch based plastic, natural oil based plastics and combination thereof.
The present invention does not utilize any edible starch or oil. Instead it discloses a bioplastic obtained from non-edible tamarind seeds, vinegar, gelatin, cellulose and glycerol. No Polylactic acid is used in the composition.
4.
US5861461 A
Discloses a biodegradable plastic composition comprising polyethylene, a biodegradable aliphatic polyester, starch (corn starch, potato starch and rice starch, acid-treated starch, esterified starch, cationic starch, and the mixtures thereof), starch plasticizer (can be glycerol), autoxidizing agent.
The present invention does not discloses starch sources mentioned in the prior art. Rather it disclose a non-edible tamarind seed as a source of starch with no use of polyethylene and aliphatic polyester.
5.
US20050158541 A1
Discloses a biodegradable fiber material molding comprising plant binder powder (a mixture of starch powder and water soluble gummy matter powder).
The present invention does not disclose any gummy matter. Rather it discloses a use of starch obtained from non-edible tamarind seeds, vinegar, gelatin,
7
cellulose and glycerol which is not mentioned in prior art patent.
6.
CN104672503 A
Discloses high barrier degradable plastics comprising microcrystalline starch, terminal carboxyl butylene succinate prepolymer, blocking agent, heat-resistant additives and lubricants.
The present invention does not disclose any component of prior art. Rather it discloses a unique bioplastic made from non-edible tamarind seed starch using vinegar, gelatin, cellulose and glycerol.
7.
US 7297394 B2
Discloses biodegradable films and sheets suitable for use as coatings, wraps and packaging materials. Biodegradable polymers include polyesters, polyesteramides, polyesterurethanes, thermoplastic starch, and other natural polymers.
No synthetic polymers are used at all in film/sheet made from biodegradable plastic of present invention.
8.
Real et al. (2015)
Discloses a biodegradable material prepared by graft copolymerization of ethyl acrylate onto tamarind kernel powder. The co-polymer is thus a blend of natural and synthetic materials. (Ref: Carbohydrate Polymers, 117, March 6, PP 11-18).
The biodegradable plastic of present invention does not involve use of ethyl acrylate at all. Rather it utilizes starch from non-edible source i.e. tamarind seeds.
From the above it is clear that present invention discloses a biodegradable plastic composition which is not anticipated by any prior art publications.
8
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide a natural biodegradable polymer and its method of production thereof.
Another object of the present invention is to disclose a non-edible starch based biodegradable plastic composition. 5
Yet another object of the present invention is to disclose a composition of biodegradable plastic comprising tamarind seed based starch with vinegar, gelatin, cellulose and glycerol.
SUMMARY OF INVENTION
The present invention provides a biodegradable plastic prepared from non-edible starch (tamarind 10 seeds) which contains w/w tamarind seed powder (3-6%), gelatin (0.5-2%), Micro-crystalline cellulose (Traces) and v/v of Vinegar (1-3%) and glycerol (2-6%). The product has a Gas Transmission rate of 168.48 cc/m2 day; water vapor transmission rate of 0.067 g/m2/day and tensile breaking force of 34.41 N. The product of the present invention has widespread industrial application e.g. in manufacture of biodegradable art objects/household objects, carry bags, 15 packaging material etc. and also biomedical field e.g. bandages, dressings, sutures. Other potential uses include biodegradable diaper parts, biodegradable sanitary napkins etc.
DETAILED DESCRIPTION OF THE INVENTION
The present invention discloses a biodegradable plastic made from natural, non-edible starch 20 derived from tamarind seeds. Composition of the same is given in Table 1.
9
Table 1: Composition of biodegradable plastic of present invention
S.No.
Component
%
1.
Tamarind seeds powder (w/w)
3-6%
2.
Gelatin (w/w)
0.5-2%
3.
Micro crystalline cellulose
Traces
4.
Vinegar (v/v)
1-3%
5.
Glycerol (v/v)
2-6%
6.
Water
Q.S.
The preparation of biodegradable plastic of present invention comprises the following steps:
i. Roasting of seeds: Tamarind seeds were roasted by heating on hot sand to remove moisture; 5
ii. Grinding and sieving: The roasted seeds were then ground to produce powder, which was sieved to produce fine powder;
iii. Addition of polymers: To the fine powder, gelatin, cellulose, vinegar, glycerol and water were added as shown in Table 1;
iv. Stirring: The resultant mixture was then stirred to produce an even composition 10 avoiding clump formation;
v. Centrifugation and heating: The mixture was then centrifuged at 20,000 rpm for 10 minutes followed by heating at Bunsen burner for 4 minutes with continuous stirring to prepare a very fine and even paste, which was then spread on an even glass surface; 15
vi. Drying: The layer was air-dried at Room temperature and room humidity for 48 hours to produce a thin sheet of biodegradable plastic.
The detailed method for the preparation of biodegradable plastic of present invention is described below in Example 1.
20
10
Example 1
Tamarind seeds were roasted for 5 minutes by heating on hot sand to remove moisture. The roasted seeds were then ground to produce powder, which was sieved to produce fine powder. To the fine powder, appropriate quantities of gelatin, cellulose, vinegar, glycerol and water were added as shown in Table 2. 5
Table 2: Illustrative composition of bio-degradable plastic of present invention
S.No.
Component
Quantity
%
1.
Tamarind seeds powder (w/w)
18 grams
4.5
2.
Gelatin(w/w)
3.5 grams
0.9%
3.
Micro crystalline cellulose
0.001 grams
Traces
4.
Vinegar (v/v)
5 ml
1.25%
5.
Glycerol (v/v)
16 ml
4%
6.
Water
400 ml
-
The resultant mixture was then stirred to produce an even composition avoiding clump formation. The mixture was then centrifuged at 20,000 rpm for 10 minutes followed by heating at Bunsen burner for 4 minutes with continuous stirring to prepare a very fine and even paste, which was then spread on an even glass surface. The layer was air-dried at Room temperature and room humidity 10 for 48 hours to produce a thin sheet of biodegradable plastic. The biodegradable plastic produced was tested for technical parameters. Technical parameters of the bio-degradable plastic of the present invention are given in Table 3 below.
11
Table 3 : Technical Characteristics of Biodegradable Plastic of Present Invention
S.No.
Name of Test
Test Method
Units
Test Value Obtained
1.
Gas Transmission Rate (GTR)
ASTMD1434
CC/m2 .day
168.48
2.
WVTR (water vapor transmission rate)
ASTME 96
Gm/ m2 .day
0.067
3.
Breaking Force / Tensile Force
Method followed from IS2508:1984
N
34.41
Novelty, Inventive Step And Industrial Application Of Present Invention
Novelty-The present invention discloses a biodegradable plastic made from natural, non-edible 5 starch derived from tamarind seeds.
Inventive Step-The technical advancement of knowledge in case of present invention lies in disclosing a biodegradable plastic composition from non-edible starch source derived from tamarind seeds and the method of production of the plastic thereof. The product of present invention can be easily produced on small scale with very low investments and is quite cheap since 10 it uses waste material i.e. tamarind seeds. Hence, the invention has considerable economic importance. The fact that despite usefulness of this product, it is neither available commercially nor disclosed in the prior art is adequate proof that it was not obvious to persons skilled in the art.
Industrial Application- The product of the present invention has widespread industrial application. It can be used in the manufacture of biodegradable carry bags, packaging material etc. 15 and also has potential applications in the field of biomedical e.g. bandages, dressings, sutures. Other potential uses include biodegradable diaper parts, biodegradable sanitary napkins etc.
In the preceding detailed description, the invention is described in its basic form. Various modifications and changes may be made thereto without departing from the broader spirit and 20 scope of the invention as set forth in the description. Described specification is to be regarded in an illustrative rather than restrictive sense. Thus without analysis, the foregoing so fully reveals the gist of the present invention that others can, by applying current knowledge, readily adapt it
12
for various applications without omitting features that from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.

I CLAIM:
1. A Biodegradable plastic WHEREIN the said biodegradable plastic is prepared from non-edible starch (tamarind seeds) and has the following composition:
S.No.
Component
%
1.
Tamarind seeds powder (w/w)
3-6%
2.
Gelatin (w/w)
0.5-2%
3.
Micro crystalline cellulose
Traces
4.
Vinegar (v/v)
1-3%
5.
Glycerol (v/v)
2-6%
6.
Water
Q.S.
2. A Biodegradable plastic WHEREIN the said biodegradable plastic is prepared from non-5 edible starch (tamarind seeds) and has technical characteristics as below:
i. Gas Transmission rate of 168.48 cc/m2 day;
ii. Water vapor transmission rate of 0.067 g/m2/day;
iii. Tensile breaking force of 34.41 N.
10
3. A process for making the biodegradable plastic as claimed in claim 1 WHEREIN the process involves the following steps:
- Roasting of seeds: Tamarind seeds were roasted by heating on hot sand to remove moisture;
- Grinding and sieving: The roasted seeds were then ground to produce powder, 15 which was sieved to produce fine powder;
- Preparation of solution: To the fine powder were added different substances in specific amounts viz. gelatin (0.5-2%), cellulose (traces), vinegar (1-3%), glycerol (2-6%) and final volume was made up with water;
- Stirring: The resultant mixture was then stirred to produce an even composition 20 avoiding clump formation;
14
- Centrifugation and heating: The mixture was then centrifuged at 20,000 rpm for 10 minutes followed by heating at Bunsen burner for 4 minutes with continuous stirring to prepare a very fine and even paste, which was then spread on an even glass surface;
- Drying: The layer was air-dried at Room temperature and room humidity for 48 5 hours to produce a thin sheet of biodegradable plastic.