A home compostable biopolymer for thermoforming

Abstract

ABSTRACT A HOME COMPOSTABLE BIOPOLYMER FOR THERMOFORMING The present invention relates to a home compostable biopolymer for thermoforming and the process for preparing the same. Moreover, the present invention provides a home compostable biopolymer for thermoforming wherein the said biopolymer comprises starch, vegetable oil derivative, compostable polyester resin, natural fillers and lubricant. The present invention is to provide a home compostable biopolymer that easily disintegrates in nature.

Description

FIELD OF THE INVENTIONThis invention pertains to a biodegradable polymer designed for home composting.Particularly, it involves a home compostable biopolymer suitable forthermoforming. More particularly, the present invention also encompasses both thebiopolymer and the method for its preparation.BACKGROUND OF THE INVENTIONPlastics are a wide range of synthetic or semi-synthetic materials that usepolymers as a main ingredient. These are the compounds that can be mouldedinto solid objects. The name plastic is derived from the elastic property of theplastics. The plasticity of these materials makes it possible for plastics to bemoulded, extruded or pressed into solid objects of various shapes.Plastic pollution is caused by the accumulation of plastic waste in theenvironment. It is harmful for humans, wildlife as well as environment. At everystage of its life cycle, from manufacturing to use and disposal, plastic is a toxicpollutant. It is a useful product that can bring danger and even death to humansand the environment. Plastic is used in almost all consumer and industrialactivities, from construction and vehicles to electronics and agriculture. Asplastic causes harmful effects on human, wildlife and environment, it becomesvery necessary to develop alternate and degradable forms of plastics and reducethe use of single use plastic.One such degradable form of plastic is biodegradable plastic. Biodegradableplastics are plastics degraded by microorganisms into water, carbon dioxide andbiomass under specified conditions. Biodegradable plastics can be applied in arange of useful ways. They can be foamed into packing materials, extruded, andinjection-moulded in modified conventional machines.Biodegradable plastics are made in a way that they can breakdown or degradewhen exposed to the sun's radiation, enzymes, bacteria, water or wind abrasion.These biodegradable plastics can be made from 1) a mixture of organic bio-basedmaterials, such as starch and cellulose; 2) biodegradable synthetic polyesters thatare fossil-based or 3) bio-based oils, such as sugarcane.Generally these biodegradable forms of bioplastics are produced from renewablebiomass sources such as vegetable fats and oils, corn starch and recycled foodwaste, etc. Some bioplastics are obtained directly by processing from naturalbiopolymers including polysaccharides (e.g., starch, cellulose, chitosan, andalginate) and proteins (e.g., soy protein, gluten, and gelatin), while others arechemically synthesized from sugar derivatives (e.g., lactic acid) and lipids (oilsand fats) from either plants or animals, or biologically generated by fermentationof sugars or lipids.Plastic thermoforming is a plastic manufacturing process that applies a force tostretch a sheet of heated thermoplastic material over an engineered mold tocreate a 3-dimensional shape or part forming. After forming, the shaped part canthen be trimmed and finished to specification to meet an end-user'srequirements. Plastic thermoforming has advantage over other plastic, metal andFRP production methods. Moreover, the thermoforming process is used toprepare thermoformed containers. The bioplastic prepared is also used in thisprocess of thermoforming and used to prepare biodegradable plates, bowls, cupsand containers, etc.Thus, there is a constant need to develop plastic materials that are environmentfriendly and cause minimum effect on the ecosystem. Thus, inventors of thepresent invention have prepared biopolymers made of natural or naturallyextracted materials such as vegetable oil derivatives and starch, making themcompostable in nature overcoming the shortcomings of the conventionallyavailable petroleum-based plastic materials.OBJECTIVE OF THE INVENTIONThe main objective of the present invention is to provide a home compostablebiopolymer for thermoforming.Yet another objective of the present invention is to provide a home compostablethermoforming biopolymer that is compatible with both single-screw and twinscrew extruders.Another objective of the present invention is to provide a home compostablebiopolymer for thermoforming that is compostable in nature.Another objective of the present invention is to provide a home compostablebiopolymer for thermoforming that is backyard compostable and disintegratescompletely in soil.Another objective of the present invention is to provide a home compostablebiopolymer for thermoforming that is used for preparing plates, bowls and cupsthat has a smooth texture indistinguishable from conventionally available plasticand other available degradable plasticsAnother objective of the present invention is to provide a home compostablebiopolymer for thermoforming having higher strength and quality than otherdegradable plasticsAnother objective of the present invention is to provide a home compostablebiopolymer for thermoforming that has reduced glass transition temperature.Another objective of the present invention is to provide a home compostablebiopolymer for thermoforming with improved water resistance.Another objective of the present invention is to provide a home compostablebiopolymer for thermoforming that is commercially viable and financiallybeneficial due to lower capital costs and power consumption.SUMMARY OF THE INVENTIONThe main aspect of the present invention is to provide a home compostablebiopolymer for thermoforming.Another main aspect of the present invention is to provide a home compostablebiopolymer for thermoforming wherein the biopolymer comprises starch,vegetable oil derivative, compostable polyester resin, natural fillers and lubricant.Another aspect of the present invention is to provide a home compostablebiopolymer for thermoforming that easily disintegrates in nature.The other aspect of the present invention is to provide a home compostablebiopolymer for thermoforming and the process for preparing the same.DESCRIPTION OF THE INVENTIONThe main embodiment of the present invention is to provide a home compostablebiopolymer for thermoforming.Unless defined otherwise, all technical and scientific terms used herein have thesame meaning as commonly understood by one of ordinary skill in the art to whichthe invention belongs. Although any methods and materials similar or equivalentto those described herein can be used in the practice or testing of the presentinvention, the preferred methods and materials are now described.As used herein, whether in a transitional phase or in the body of a claim, the terms"comprise(s)" and "comprising" are to be interpreted as having an open-endedmeaning. That is, the terms are to be interpreted synonymously with the phrases"having at least" or "including at least". When used in the context of a process, theterm "comprising" means that the process includes at least the recited steps, butmay include additional steps. When used in the context of a composition, the term"comprising" means that the composition includes at least the recited features orcomponents, but may also include additional features or components.As used herein, the singular forms "a," "an" and "the" specifically also encompassthe plural forms of the terms to which they refer, unless the content clearly dictatesotherwise.The following terms shall have, for the purposes of this application, the respectivemeanings set forth below."Optional" or "optionally' means that the subsequently described event orcircumstance may or may not occur and that the description includes instanceswhere the event occurs and instances where it does not.The term "about" is used herein to means approximately, in the region of, roughly,or around. When the term "about" is used in conjunction with a numerical range, itmodifies that range by extending the boundaries above and below the numericalvalues set forth. In general, the term "about" or "approximately" is used herein tomodify a numerical value above and below the stated value by a variance of 20%.The present invention overcomes the aforesaid drawbacks of the above, and otherobjects, features, and advantages of the present invention will now be described ingreater detail. Also, the following description includes various specific details andis to be regarded as merely exemplary. Accordingly, those of ordinary skill in theart will recognize that: without departing from the scope and spirit of the presentdisclosure and its various embodiments there may be any number of changes andmodifications described herein.As will be understood by one skilled in the art, for any and all purposes, such as interms of providing a written description, all ranges disclosed herein alsoencompass any and all possible sub-ranges and combinations of sub-rangesthereof. Any listed range can be easily recognized as sufficiently describing andenabling the same range being broken down into at least equal halves, thirds,quarters, fifths, tenths, et cetera As a non-limiting example, each range discussedherein can be readily broken down into a lower third, middle third and upper third,etc As will also be understood by one skilled in the art all language such as "upto," "at least," and the like include the number recited and refer to ranges whichcan be subsequently broken down into sub-ranges as discussed above.Nothing in this disclosure is to be construed as an admission that the embodimentsdescribed in this disclosure are not entitled to antedate such disclosure by virtue ofprior invention. As used in this document, the term "comprising" means"including, but not limited to.The term "thermoforming" used herein, is defined as a manufacturing processwhere a plastic sheet is heated to a pliable forming temperature, formed to aspecific shape in a mold, and trimmed to create a usable product.The main embodiment of the present invention is to provide a home compostablebiopolymer for injection moulding, wherein said biopolymer comprises of starch,natural filler, compostable polyester resin, lubricant and vegetative oil derivative.As per one embodiment of the present invention, wherein said starch is used in therange of 0.1 to 100 parts, more preferably 1 to 50 parts and most preferably 5 to 40parts.As per one embodiment of the present invention, wherein said compostablepolyester resin is selected from but not limited to poly(ε-caprolactone),polyglyconate, poly(dioxanone), polyhydroxyalkanoates (PHA) and polymericstarches, polybutylene adipate terephthalate, polyhydroxybutyrate, polybutylenesuccinate, polyhydroxyhexanoate, polyethylene terephthalate andpolycaprolactone.As per a preferred embodiment, the compostable polyester resin used ispolybutylene adipate terephthalate.As per one embodiment of the present invention, wherein said compostablepolyester resin used in the present invention is in the range of 5 to 80 parts, morepreferably 10 to 70 parts and most preferably in 10 to 65 parts.As per one embodiment of the present invention, wherein said natural filler isselected from but not limited to calcium carbonate, kaolin, talcum powder,titanium dioxide, mica and polynite.As per a preferred embodiment, the natural filler used is calcium carbonate.As per one embodiment of the present invention, the said natural fillers used in thepresent invention is in the range of 1 to 60 parts natural fillers, more preferably 5to 40 parts natural fillers, and most preferably 5 to 35 parts natural fillers.As per one another embodiment of the present invention, wherein said lubricant isselected from but not limited to one or more of amide organic compounds, stearicacid, wax, vegetable oils and n-butyl stearate.As per a preferred embodiment, the said lubricant used is stearic acid.As per one another embodiment of the present invention, the said lubricant used inthe present invention is in the range of 0.1 to 40 parts, more preferably 1 to 30parts and 2 to 15 parts of lubricant.As per another embodiment of the present invention, the said vegetable oilderivative is selected from but not limited to fatty acids, fatty acid methyl esters,Epoxidized vegetable oils, dimerized fatty acids, and glycerin, ricinoleic acid andcastor oil derivatives.As per a preferred embodiment, the said vegetable oil derivative used isEpoxidized vegetable oils and more preferably Epoxidized soybean oil.As per one another embodiment of the present invention, the vegetable oilderivatives used in the present invention is in the range of 0.1 to 40 parts, morepreferably 1 to 30 parts and most preferably 2 to 20 parts.According to another main embodiment, the present invention provides the processof preparing the home compostable biopolymer for thermoforming, comprising thefollowing steps:a. Mixing starch, vegetable oil derivative, compostable polyester resin,and all processing aids in high-speed mixers at 25°C-75°c;b. Adding the homogenous mixture of step (a) to screw machine at a feedrate of 500 grams / hour;c. Pelletizing the compound of step (b) through a twin or single-screwextruder;d. Moulding the pelletized compound of step (c) through conventionalthermoforming machine at 140°C-180°C to get the final product.As per another embodiment of the present invention, the biopolymer comprises of0.1 to 100 parts of starch, 5 to 80 parts of compostable polyester resin, 1 to 60parts of natural fillers, 0.1 to 40 parts of lubricant, and 0.1 to 40 parts of vegetableoil derivative.As per another embodiment of the present invention, the biopolymer comprises of1 to 50 parts of starch, 10 to 70 parts of compostable polyester resin, 5 to 40 partsof natural fillers, 1 to 30 parts of lubricant, and 1 to 30 parts of vegetable oilderivative.As per another embodiment of the present invention, the biopolymer comprises of5 to 40 parts of starch, 10 to 65 parts of compostable polyester resin, 5 to 35 partsof natural fillers, 2 to 15 parts of lubricant, and 2 to 20 parts of vegetable oilderivative.As per one embodiment of the present invention, the home compostablebiopolymer for thermoforming can be used in the preparation of productsincluding but not limited to kitchen ware products such as plates, bowls and cups.Another embodiment of the present invention, is to provide a home compostablebiopolymer for thermoforming wherein said biopolymer is having higher strength,smooth surface, easy to manufacture and is cost effective.The invention is further illustrated by the following examples which are providedto be exemplary of the invention and do not limit the scope of the invention. Whilethe present invention has been described in terms of its specific embodiments,certain modifications and equivalents will be apparent to those skilled in the artand are intended to be included within the scope of the present invention.EXAMPLESEXAMPLE 1: COMPOSITION OF HOME COMPOSTABLETable 1: Composition of home compostable biopolymer for thermoformingEXAMPLE 2: TRIAL BATCHES OF BIOPOLYMER FORTHERMOFORMINGTable 2: Trials for optimization of home compostable biopolymer forthermoformingThe process for preparation of a home compostable biopolymer for thermoformingcomprises following steps:a. Mixed 10 parts starch, 5 parts Epoxidized soybean oil, 60 partspolybutylene adipate terephthalate, 30 parts calcium carbonate and 4parts stearic acid in high-speed mixers at 25°C-75°C;b. Added the homogenous mixture of step (a) to screw machine at a feedrate of 500 grams / hour;c. Pelletized the compound of step (b) through a twin or single-screwextruder;d. Moulded the pelletized compound of step (c) through conventionalthermoforming machine at 140°C-180°C to get the final product.EXAMPLE 3: EVALUATION PARAMETERS FOR TRIAL BATCHES OFA HOME COMPOSTABLE BIOPOLYMERTable 3: Evaluation of trial batched of home compostable biopolymer forthermoformingEXAMPLE 4: OPTIMIZED BATCH OF A HOME COMPOSTABLEBIOPOLYMER FOR THERMOFORMINGSr. No. PARAMETERS OPTIMIZED BATCH 1 Melt flow index (MFI) 2.3 g / 10 min 2 Glass transition temperature -20°C 3 Tensile strength (TS) 15MPa 4 Melting temperature (TM) 125°C 5 Yield strength 70 MPa 6 Elongation at break 300%7 Processing in conventional blow film machine Easy4: Optimized batch of home compostable biopolymer forthermoformingEXAMPLE 5: COMPARITIVE ANALYSIS OF MARKETEDBIOPOLYMER WITH HOME COMPOSTABLE BIOPOLYMER FORTHERMOFORMINGA comparative analysis was carried for home compostable biopolymer forthermoforming with the marketed formulation, where the marketed formulationcomprises of 40 parts polypropylene, 50 parts starch, 20 parts calcium carbonateand 2 parts zinc stearate.The polypropylene found in the marketed formulations is not a compostablepolymer so the marketed formulations are not completely or partially compostablein nature. Further, here starch is only used as a filler and not as main binder or cobinder in the formula, so it reduces the strength and increase rigidity of thematerial. Due to using of biodegradable starch with non-biodegradablepolypropylene it not compatible and processing instability accurse while highhumid condition comes, it will neither single use nor multiple use.

Claims

1. A home compostable biopolymer for thermoforming, wherein said biopolymer comprises of starch, natural filler, compostable polyester resin, lubricant and vegetative oil derivative.

2. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein said starch is used in the range of 0.1 to 100 parts, more preferably 1 to 50 parts and most preferably 5 to 40 parts.

3. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein said compostable polyester resin is selected from but not limited to poly(ε-caprolactone), polyglyconate, poly(dioxanone), polyhydroxyalkanoates (PHA) and polymeric starches, polybutylene adipate terephthalate, polyhydroxybutyrate, polybutylene succinate, polyhydroxyhexanoate, polyethylene terephthalate and polycaprolactone.

4. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein said natural filler is selected from but not limited to calcium carbonate, kaolin, talcum powder, titanium dioxide, mica and polynite.

5. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein said lubricant is selected from but not limited to one or more of amide organic compounds, stearic acid, and wax, vegetable oils and n-butyl stearate.

6. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein the vegetable oil derivative is selected from but not limited to fatty acids, fatty acid methyl esters, Epoxidized vegetable oils, dimerized fatty acids, Glycerine, ricinoleic acid and castor oil derivatives.

7. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein the process for preparation of the biopolymer comprises the following steps: a. Mixing starch, vegetable oil derivative, compostable polyester resin, and all processing aids in high-speed mixers at 25°C-75°c; b. Adding the homogenous mixture of step (a) to screw machine at a feed rate of 500 grams / hour; c. Pelletizing the compound of step (b) through a twin or singlescrew extruder; d. Moulding the pelletized compound of step (c) through conventional thermoforming machine at 140°C-180°C to get the final product.

8. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein the biopolymer comprises of 0.1 to 100 parts of starch, 5 to 80 parts of compostable polyester resin, 1 to 60 parts of natural fillers, 0.1 to 40 parts of lubricant, and 0.1 to 40 parts of vegetable oil derivative.

9. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein the biopolymer comprises of 1 to 50 parts of starch, 10 to 70 parts of compostable polyester resin, 5 to 40 parts of natural fillers, 1 to 30 parts of lubricant, and 1 to 30 parts of vegetable oil derivative.

10. The home compostable biopolymer for thermoforming as claimed in claim 1, wherein the biopolymer comprises of 5 to 40 parts of starch, 10 to 65 parts of compostable polyester resin, 5 to 35 parts of natural fillers, 2 to 15 parts of lubricant, and 2 to 20 parts of vegetable oil derivative.