Methods of preparation of low cost thermosetting bioplastics

Abstract

The present invention describes a low cost process for preparation of a bio-plastic wherein the rice flour / starch is mixed without the need for external synthetic ingredients, with improved mechanical properties in the ratio of rice flour / starch :water is 1:10-10:1 (w / w); with plasticizer rice flour / starch: plasticizer in the ratio 99:1 to 1:1 (w / w) and also combine with one cross-linking agent which mixed with rice flour / starch in the ratio 99:1 to 1:1 (w / w), along with natural additives wherein that the ratio of such additives with respect to rice flour / starch is in the ratio nil to 1:3 (w / w). Heating the mixture in a temperature range of 60°C to 180°C for an average time of 1-60 minutes; cooling of such solution to an average temperature ranging from 20-80°C and subsequent drying until water content in final bio-plastic product is less than 5% (w / w).

Description

[0001] Field of theThe p r e s e n t invention relates to process of preparation of Biodegradable plastics and the product thereof. More specifically the invention describes a process for preparation of next generation of bio-plastic from rice flour / starch without the need for external synthetic ingredients, with improved mechanical properties using a low cost process. Plastics lave become an integral part of our lives. The problems of conventional plastics are that they take decades to degrade in nature and are produced by nonrenewable sources like petroleum, Coal and natural gas. Environmental, economic, and safety challenges have provoked many scientists to partially substitute petrochemical-based polymers with biodegradable ones i.e. bio-plastics. Studies reveal that bio-plastics are environmental friendly as compared to traditional plastics for their production results in the emission of less greenhouse gases such as carbon dioxide, which is one of the prime sources of air pollution and leads to environmental issues such as global warming, climate change, etc. KR20220046912A describes (step 1) thermo mechanically mixing or kneading wood- based biomass and starch based biomass at a temperature of 100 to 130 ° C. in the presence of a plasticizer to prepare a biomass plasticized composite; (Step 2) a first low temperature pulverization step of pulverizing the biomass plasticized composite, polymer and binder at a high speed of 1000 to 2500 rpm at a temperature of 80 to 150°C; (Step 3) a second cold grinding step of pulverizing the first low-temperature pulverized powder at a high speed of 1000 to 2500 rpm at a temperature of -20 to 0 °C; and (Step 4) an extrusion step of supplying the secondary cold-ground powder to a twin-screw extruder having a length-to diameter ratio (LD ratio) of 60 or more at a constant speed and extruding while discharging steam generated at a temperature of 130 to 170° C. under reduced pressure. It relates to a method for producing bio- plastics containing lignocellulosic biomass and starch-based biomass where wood- based and starch-based biomass and polymers are mixed and compounded to produce bio-plastics without deteriorating physical properties including strength of the polymer while preventing deterioration due to carbonization and oxidation of the wood-based and starch-based biomass. The present invention is comprises of 100% bio-ingredients and no external polymer is added to produce the final bio-plastic. Water is a significant plasticizer ranging from 10-90% w / w with respect to rice-flour / starch in present invention where-as water is extremely low and hence its impact on final product is low in KR20220046912A. The present invention doesn’t use wood as an ingredient unlike the cited invention. Addition of external lignocellulosic biomass is not mandatory to achieve the mechanical properties of the final bio-plastic and no external metallic coupling agent is used on our invention unlike the cited invention. SG10201904795A1 discloses a bioplastic and method to manufacture said bioplastic a grainbased bioplastic comprising egg white, glutinous rice and water. A method to manufacture the bioplastic is also provided. Raw materials used for the bioplastic are able to be consumed and are bio-degradable. The raw materials also do not include any synthetic agents / additives, and the production method does not require use of have any toxic substances The present process does not require addition of strong acids and other non- biocompatible materials unlike processes known in the prior art. Further, the raw material being rice flour and other starch is abundantly available, which makes it extremely simple and feasible for commercial production. The present invention is a thermosetting bio-plastic. In our invention, the following are unique relative to SG10201904795A1: No egg white is added in our invention and rice flour / starch is present in the range of 10-90% w / w relative to Claim 1-5, 10 in SG10201904795A1. The present invention uses normal rice flour / starch, and is not specific to glutinous rice (which has lower amounts of fiber, fat, sugar, and starch) due to which overall strength is superior to Claims 1-5, 10 in SG10201904795A1. In present invention water acts as one of the major plasticizers ranging from 10-90% w / w, along with a plasticizer from at least one of esters of carboxylic acids, isosorbide diesters, esters based on vegetable oils, esters based on polyols of origin vegetable, epoxidized polyol ester, modified vegetable oils, modified soybean oils, epoxidized vegetable oils , este rs of glycerin, polymer esters, fatty acid esters, adipates, polyadipa tes, bis (2-ethylhexyl) adipates , citrates, acetyltributylcitrates, acetylated monoglycerides, phospha tes, trimellitates, malates, succinates, sebacates, stearates, azelates, oligomeric plasticizers and oligomeric polymers, lubricants, waxes, lubricants based Therefore, to the best of our knowledge, none of the above mentioned priorart individually or collectively, the proposed system and embodimentsindicated and disclosed the present invention. Object of theThe objective o f the present invention is to prepare low-cost bio-plastic from rice / starch flour. Another objective of the present invention is to prepare a low-cost bio-plastic which can easily substitute petro-plastic in various applications. Further objective of the present invention is to prepare a low-cost bio-plastic which is resistant to heat and water. The objec tive of the present invention is to prepare a low-cost bio-plastic which has mechanical properties better than petro-plastic. The objective of the present invention is to prepare a low-cost bio-plastic which easily biodegradable in lesser time. of the The present invention describes a process for preparation of a bio-plastic wherein the rice flour and / or starch is mixed in the ratio of rice flour / starch :water is 1:10-10:1 (w / w); mixed with plasticizer rice flour / starch: plasticizer in the ratio 99:1 to 1:1 (w / w) and also combined with one cross-linking agent which mixed with rice flour / starch in rice flour : cross linking agent in the ratio 99:1 to 1:1 (w / w), along with natural additives wherein that the ratio of such additives with respect to rice flour / starch is in the ratio nil to 1:3 (w / w) . Then heating the mixture in a temperature range of 60°C to 180°C for an average time of 1-60 minutes; cooling of such solution to an average temperature ranging from 20-80°C and subsequent drying until water content in final bio-plastic product is less than 5% (w / w). In an aspe ct of the present invention a commercial viable production of bio-plastic is produce d to enable faster r eplacement of petro plastic for various applications. In further aspect, the present invention provides a starch-based bioplastic material that has good mechanical characteristics with biocompatibility. of the DComplete und e r s t a n d i n g o f t he system and method of the present invention may beobtained reference to the followingFigures Fifure 1 : Demonstrati o n o f v a r i o u s c o l o r s o f i nvented Bio-plastics Figure Figure 2: a. Demonstration of strong metal coating of invented Bio-plastics Figure 2: b. Demonstration of high transparency of 0.1 mm of invented thermosetting Bio-plastics Figure 2: c. Transparency of 0.1 mm recycled HDPE film Figure 2: d Transparency of 0.1 mm recycled LDPE film Figure 3: Effect of film thickness for invented Bio-plastic Figure 4: Demonstration of Thermosetting nature of invented bio-plastic Figure 5: Demonstration of heat resistance of invented bio-plastic Figure 5a: Original Figure 5b : After 30 minutes at 200oC Figure 5c: After 60 minutes at 200oC Figure 6: TGA and TCG crest Figure 7: TGA Curve of Starch bio plastic and Composite bioplastic Figure 8: IR data TCG crest Detailed of the The foll owing is a detaile d description of embodiments of the disclosuredepicted in accompanying drawings. The embodiments are in such detail asto clearly com municate disclosure. The amount of detail offered has theintention to cover all modifications, and alternatives falling within the scope of the present disclosure as defined by the . The accompanying drawings, which are incorporated in and constitute a part of the illustrate an embodiment of the invention, and together with thedescription, serve to explain principles of the As used in the description herein and throughout the claim s t hat follow, themeaning of “an,” and “the” includes plural reference unless the context clearlydictates The present invention d escribes a process for preparation of bio-plastic materials composed of starch that have high biocompatibility and high tensile strength comprising steps of; 1. Mixing and heating of rice flour and / or starch with water, plasticizer, cross-linking agent and natural fillers 2. Cooling of the above solution: and 3. Drying said resulting solution to form films, sheets, formations etc. In the preferred embodiment, the method discloses preparing biodegradable plastic from rice flour / starch by mixing rice flour and / or starch with water such that ratio of rice flour / starch:water is 1:10-10:1 (w / w), and using one plasticizer mixed with rice flour / starch such that rice flour / starch:plasticizer is in the ratio 99:1 to 1:1 (w / w) and one cross-linking agent mixed with rice flour / starch such that rice flour / starch:cross linking agent is in the ratio 99:1 to 1:1 (w / w), along with natural additives such that the ratio of such additives with respect to rice flour / starch is in the ratio nil to 1:3 (w / w) , heating to temperature of 60°C to 180°C for an average time of 1-60 minutes; cooling of the solution to an average temperature ranging from 20-80°C; drying such solution until water content in final bio-plastic product is less than 5% (w / w). In the preferred embodiment, rice starch is converted to bio-plastic films, sheets, formations, etc. using the gelatinisation route involving steps of mixing and heating starch mixed with water, plasticizer, cross-linking agent and natural additives / fillers The plasticizer used in the process is one of esters of carboxylic acids, isosorbide diesters, esters based on vegetable oils, esters based on polyols of origin vegetable, epoxidized polyol ester, modified vegetable oils, modified soybean oils, epoxidized vegetable oils, esters of glycerin, polymer esters, fatty acid esters, adipates, polyadipates, bis (2-ethylhexyl) adipates , citrates, acetyltributylcitrates, acetylated monoglycerides, phosphates, trimellitates, malates, succinates, sebacates, stearates, azelates, oligomeric plasticizers and oligomeric polymers, lubricants, waxes, lubricants based on ethylene bis-stearamide or ethylene bis-oleamide and mixtures thereof. The cross linking agent is one of mono-substituted succinic anhydride, linear or branched aliphatic carboxylic acid, and / or one of its salts, such as 2- hydroxy-1,2,3-propanetricarboxylic acid, ethanoic acid, tartaric acid, ascorbic acid, acetylesalicyclic acid, oxalic acid, formic acid, tartaric acid etc. After drying this forms the final bio-plastic product, which can then be converted to various forms like sheets, films, formations etc. The mechanical properties may be varied by a combination of variation in the content of the various ingredients, cooking and process times, rate of cooling, and rate of drying. The bio-plastic prepared is blended with an additive from a polysaccharide consisting of a linear chain of several hundred to many thousands of β linked D-glucose units, a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, waste paper, or rags, water soluble colors, minerals derived from clay like hydrated converted to films, sheets, disposable table and kitchen ware etc. such that the ratio of such additives with respect to rice flour / starch is in the ratio nil to 1:3 (w / w). The density of bioplastic ranging from 1.10-1.22 g / cc wherein the bio-plastic completely degrades in mud and / or water within 30-90 days, and is resistant to intermittent exposure to water without complete degradation for 30-60 days. The bio-plastic exhibit high translucency, high elongation-at-break varies in the ranges 10.0-35.2% for 0.25mm film thickness. The bio-plastic exhibits thermosetting and high heat resistance for intermittent exposure from 50-200oC and continuous exposure to a temperature from 50-150oC. The thermosetting nature of present bio- plastic which –makes it heat resistant upto 200 degC without melting, Following explains the non-limiting examples Example-1 100 parts of rice flour mixed with 40 parts of glycerol, 20 parts of acetic acid. Water is mixed in a ratio such that water: rice flour is 10:1 (w / w). This mixture is cooked appropriately at an average temperature ranging from 80-120 degC, cooled, moulded and dried. The bio plastic material exhibits tensile strength 8.9 MPa, elongation at break 25.7% and modulus of elasticity 104.0 Exmple-2 100 parts of rice flour mixed with 40 parts of glycerol, 20 parts of acetic acid. Water is mixed in a ratio such that water: rice flour is 5:1 (w / w). This mixture is cooked appropriately at an average temperature ranging from 80-120 degC, cooled, moulded and dried. The bio plastic material exhibits tensile strength 3.5 MPa, elongation at break 20.5% and modulus of elasticity Example-3 100 parts of rice flour mixed with 20 parts of glycerol, 40 parts of acetic acid. Water is mixed in a ratio such that water: rice flour is 10:1 (w / w). This mixture is cooked appropriately at an average temperature ranging from 80-120 degC, cooled, moulded and dried. The bio plastic material exhibits tensile strength 1.8 MPa, elongation at break 10 % and modulus of elasticity 22.3. Example-4 100 parts of rice flour mixed with 15 parts of glycerol, 20 parts of acetic acid. Water is mixed in a ratio such that water: rice flour is 10:1 (w / w). This mixture is cooked appropriately at an average temperature ranging from 80-120 degC, cooled, moulded and dried. The bio plastic material exhibits tensile strength 2.3 MPa, elongation at break 35.2 % and modulus of elasticity 30.1 Table -1 exhibits various compositions of bio-plastic containing rice flour, acetic acid, glycerol, and water were prepared and results observed for bio-plastic samples of average film thickness 0.25 mm and density ranging from 1.10-1.22 g / cc: Detail UOM Sample#1 Sample#2 Sample#3 Sample#4 In the preferred embodiment, a. Addition of higher water increases overall cooking time and strength of the final plastic by 5-10 MPa. b. Addition of higher glycerol reduces tensile strength of final plastic by 5-10 MPa. c. Addition of higher acetic acid increases strength of final plastic by 5-10 MPa. d. Moisture removal happens between 86.59 - 114.88 degC with a net weight loss of 5.5% while greatest mass loss of 43.2399% occurs between 283.42 – 320.29 degC. Full decomposition temperature is 460 degC. This relative to 50% of weight loss occurred at 291 C and 303 C for other known bioplastics (Figure 7) Table 2: Comparison between petro-plastic, bio-plastics and our invention. Description Petro-plastic Competitor RBG’s Bio- Bi l i l i Advantages: These biocompatible and biodegradable bio-plastic materials (starch based bio- plastics) have myriad applications and uses, which range from packaging daily use plastic poly-bags, industrial packaging, , food / non-food applications, coatings, paints, automotive parts, electronic parts, electrical components, table ware, gloves, fair- weather tents, disposable synringes etc

Claims

We claim: Amethod of preparing biodegradable plastic from Rice flour / starchcomprises Mixing rice flour with water wherein ratio of rice flour:water is 1:10-10:1 (w / w), and mixed with one plasticizer in the ratio rice flour: plasticizer varies from 99:1 to 1:1 (w / w) and with one cross-linking agent in the ratio 99:1 to 1:1 (w / w) and with natural additives in the ratio nil to 1:3 (w / w) heating to temperature of 60°C to 180°C for an average time of 1-60 minutescooling the solution to an average temperature ranging from 20-80°C;drying until water content in final bio-plastic product is less than 5% (w / w).Theprocess as claimed in claim 1, wherein the plasticizer used is fromesters of carboxylic acids, isosorbide diesters, esters based on vegetable oils, esters based on polyols of origin vegetable, epoxidized polyol ester, modified vegetable oils, modified soybean oils, epoxidized vegetable oils, esters of glycerin, polymer esters, fatty acid esters, adipates, polyadipates, bis (2-ethylhexyl) adipates , citrates, acetyltributylcitrates, acetylated monoglycerides, phosphates, trimellitates, malates, succinates, sebacates, stearates, azelates, oligomeric plasticizers and oligomeric polymers, lubricants, waxes, lubricants based on ethylene bis-stearamide or ethylene bis-oleamide. The process as claimed in claim 1, wherein the rice flour : plasticizer used inin the ratio 99:1 to 1:1 (w / w). The process as claimed in claim 1, wherein cross linking agent is sourcedfrom mono- substituted succinic anhydride, linear or branched aliphatic carboxylic acid and one of its salts, and the cross linking agent is mixed with rice flour / in the ratio 99:1 to 1:1 (w / w) Athermosetting bio-plastic material comprising of

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