A home compostable biopolymer for injection moulding

Abstract

The present invention relates to a home compostable biopolymer for injection moulding and the process for preparing the same. Moreover, the present invention provides a home compostable biopolymer for injection moulding wherein the said biopolymer comprises starch, vegetable oil derivative, compostable polyester resin, natural fillers, lubricant and compatibilizer. The present invention is to provide a home compostable biopolymer that easily disintegrates in nature.

Description

[0001] A HOME COMPOSTABLE BIOPOLYMER FOR INJECTION MOULDING

[0002] FIELD OF THE INVENTION

[0003] This invention pertains to a biodegradable polymer designed for home composting. Particularly, it involves a home compostable biopolymer suitable for use in injection moulding. The present invention also encompasses both the biopolymer and the method for its preparation.

[0004] BACKGROUND OF THE INVENTION

[0005] Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. These are the compounds that can be moulded into solid objects. The name plastic is derived from the elastic property of the plastics. The plasticity of these materials makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes.

[0006] Plastic pollution is the accumulation of these plastic objects and particles in the Earth’s environment that adversely affects human, wildlife and the environment itself. Plastic pollution can afflict land, waterways and oceans. Over 460 million metric tons of plastic is produced every year for use in a wide variety of applications. Plastic is used in almost all consumer and industrial activities, from construction and vehicles to electronics and agriculture. As plastic causes harmful effects on human, wildlife and environment, it becomes very necessary to develop alternate and degradable forms of plastics.

[0007] One such degradable form of plastic is biodegradable plastic. Biodegradable plastics are plastics degraded by microorganisms into water, carbon dioxide and biomass under specified conditions. Biodegradable plastics can be applied in a range of useful ways. They can be foamed into packing materials, extruded, and injection-moulded in modified conventional machines. Biodegradable plastics are made in a way that they can breakdown or degrade when 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 -based materials, such as starch and cellulose; 2) biodegradable synthetic polyesters that are fossil-based or 3) bio-based oils, such as sugarcane.

[0008] Injection moulding is a manufacturing process for producing parts by injecting molten material into a mould, or mold. This process can be performed with a host of materials mainly including metals, glasses, elastomers, confections, and most commonly thermoplastic and thermosetting polymers. Materials for the part is fed into a heated barrel, mixed and injected into a mould cavity where it cools and hardens to the configuration of the cavity. Injection moulding is widely used for manufacturing a variety of parts, from the smallest components to entire body panels of cars.

[0009] Plastic injection is a method to obtain moulded products by injecting plastic materials molten by heat into a mold, and then cooling and solidifying them. The advantages of plastic injection moulding for manufacturing parts methods include fast production speed, high efficiency, and automation of operation, shapes, and size flexibility. Moreover, the injection moulding products are accurate in size, easy to be replaced, and the mold parts can be formed into complex shapes. This eco-friendly material is suitable for the moulding processing fields such as mass production and complex shape products.

[0010] But there are a few general problems which are associated with this injection moulding method. There are common moulding defects associated with this method such as flow lines, burn marks, vacuum voids, warping, sink marks, discolouration and jetting. These are the few issues that arrive with the plastic injection moulding process. Thus, there is a need to overcome all these disadvantages and develop a method for obtaining a biodegradable polymer that helps to overcome all the disadvantages of the conventionally available polymer for injection moulding.

[0011] There is a constant need to develop plastic materials that are environment friendly and cause minimum effect on the ecosystem. Thus, inventors of the present invention have prepared biopolymers made of natural or naturally extracted materials such as vegetable oil derivatives and starch, making them compostable in nature overcoming the shortcomings of the conventionally available petroleumbased plastic materials.

[0012] OBJECTIVE OF THE INVENTION

[0013] The main objective of the present invention is to provide a home compostable biopolymer for injection moulding.

[0014] Yet another objective of the present invention is to provide a home compostable injection moulding biopolymer that is compatible with both single-screw and twin- screw extruders.

[0015] Another objective of the present invention is to provide a home compostable biopolymer for injection moulding that is compostable in nature.

[0016] Another objective of the present invention is to provide a home compostable biopolymer for injection moulding that is backyard compostable and disintegrates completely in soil.

[0017] Another objective of the present invention is to provide a home compostable biopolymer for injection moulding that is used for preparing spoons, forks and knives that has a smooth texture indistinguishable from conventionally available plastic and other available degradable alternatives. Another objective of the present invention is to provide a home compostable biopolymer for injection moulding having higher strength and quality other than biodegradable materials.

[0018] Another objective of the present invention is to provide a home compostable biopolymer for injection moulding that is commercially viable and financially beneficial due to lower capital costs and power consumption.

[0019] SUMMARY OF THE INVENTION

[0020] The main aspect of the present invention is to provide a home compostable biopolymer for injection moulding.

[0021] Another main aspect of the present invention is to provide a home compostable biopolymer for injection moulding wherein the biopolymer comprises starch, vegetable oil derivative, compostable polyester resin, natural fillers, lubricant and compatibilizer.

[0022] Another aspect of the present invention is to provide a home compostable biopolymer for injection moulding that easily disintegrates in nature.

[0023] The other aspect of the present invention is to provide a home compostable biopolymer for injection moulding that has good environmental resistance and gets degrades easily in industrial composting facility.

[0024] DESCRIPTION OF THE INVENTION

[0025] The main embodiment of the present invention is to provide a home compostable biopolymer for injection moulding.

[0026] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described.

[0027] 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-ended meaning. 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, the term “comprising” means that the process includes at least the recited steps, but may include additional steps. When used in the context of a composition, the term “comprising” means that the composition includes at least the recited features or components, but may also include additional features or components.

[0028] As used herein, the singular forms “a,” “an” and “the” specifically also encompass the plural forms of the terms to which they refer, unless the content clearly dictates otherwise.

[0029] The following terms shall have, for the purposes of this application, the respective meanings set forth below.

[0030] "Optional" or "optionally' means that the subsequently described event or circumstance may or may not occur and that the description includes instances where the event occurs and instances where it does not.

[0031] 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, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” or “approximately” is used herein to modify a numerical value above and below the stated value by a variance of 20%.

[0032] The present invention overcomes the aforesaid drawbacks of the above, and other objects, features, and advantages of the present invention will now be described in greater detail. Also, the following description includes various specific details and is to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that: without departing from the scope and spirit of the present disclosure and its various embodiments there may be any number of changes and modifications described herein.

[0033] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible sub-ranges and combinations of sub-ranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, et cetera As a non-limiting example, each range discussed herein 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 “up to,” “at least,” and the like include the number recited and refer to ranges which can be subsequently broken down into sub-ranges as discussed above.

[0034] Nothing in this disclosure is to be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by virtue of prior invention. As used in this document, the term "comprising" means "including, but not limited to.

[0035] The term “injection moulding” used herein, is defined as a method to obtain molded products by injection plastic materials molten by heat into a mold, and then cooling and solidifying them.

[0036] The term “pellets or granules or biopolymer” used herein, refers to same forms or types of raw materials used in manufacturing processes and can be used interchangeably. A main embodiment of the present invention is to provide a home compostable biopolymer for injection moulding.

[0037] Another main embodiment of the present invention is a home compostable biopolymer for injection moulding of the present invention, wherein biopolymer comprises starch, compostable polyester resin, natural fillers, lubricant and compatibilizer.

[0038] As per one embodiment of the present invention, said starch is used in the range of 1-50 parts, more preferably 5-40 parts, and most preferably 15-35 parts.

[0039] As per one embodiment of the present invention, said compostable polyester resin is selected from but not limited to polybutylene adipate terephthalate, polyhydroxybutyrate, polyhydroxyalkalonates, polybutylene succinate polyhydroxyhexanoate, polyethylene terephthalate and polycaprolactone.

[0040] As per preferred embodiment of the present invention, polybutylene adipate terephthalate(PBAT), polybutylene succinate (PBS) can be used as a compostable polyester resin.

[0041] As per one embodiment of the present invention, said compostable polyester resin is used in the range of 10-70 parts, more preferably 10-65 parts and most preferably in 10-55 parts.

[0042] As per one embodiment of the present invention, said natural filler is selected from but not limited to calcium carbonate, kaolin, talcum powder, titanium dioxide, mica and polynite.

[0043] As per preferred embodiment of the present invention calcium carbonate is used as a natural filler. As per one embodiment of the present invention, said natural filler is used in the range of 1-50 parts of natural fillers, more preferably 10-40 parts of natural fillers, and most preferably 15-25 parts of natural fillers.

[0044] As per one embodiment of the present invention, said lubricant is selected from but not limited to amide organic compounds, stearic acid, wax, vegetable oil and n-butyl stearate.

[0045] As per preferred embodiment of the present invention, stearic acid is used as a lubricant.

[0046] As per one embodiment of the present invention, said lubricant is used in the range of 0.1 to 10 parts, more preferably 0.2 to 5 parts and 0.3 to 3 parts of lubricant.

[0047] As per one embodiment of the present invention, said compatibilizer is selected from but not limited to citric acid, maleic anhydride, tween 80, epoxidized vegetable oils, biodegradable polyester, polyhydric fatty ester and polyhydric fatty acid white oil and / or mineral oil.

[0048] As per preferred embodiment of the present invention, epoxidized vegetable oils is used as compatibilizer. As per most preferred embodiment, Epoxidized soybean oil is used as a compatibilizer.

[0049] As per one embodiment of the present invention, said compatibilizer used in the range of 0.1 to 10 parts, more preferably 0.2 to 5 parts and 0.3 to 3 parts of compatibilizer.

[0050] As per one embodiment of the present invention, the home compostable biopolymer for injection moulding, wherein said biopolymer comprises: a. 1-50 parts, more preferably 5-35 parts, and most preferably 15-30 parts of starch; b. 10-70 parts, more preferably 10-65 parts and most preferably in 10-55 parts of compostable polyester resin, c. 1-50 parts of natural fillers, more preferably of 10-40 parts natural fillers, and most preferably of 15-25 parts natural fillers; d. 0.1 to 10 parts, more preferably 0.2 to 5 parts and 0.3 to 3 parts of lubricant; and e. 0.1 to 10 parts, more preferably 0.2 to 5 parts and 0.3 to 3 parts of compatibilizer.

[0051] As per one embodiment, the process of preparing the home compostable biopolymer for injection moulding, comprising the following steps: a. Mixing starch, lubricant, compostable polyester resin, and all processing aids in high-speed mixers at 800 RPM heats it up to 120°C until moisture is removed to obtain a homogenous mixture; b. Adding the homogenous mixture of step (a) to screw machine at a feed rate of 500 grams / hour to obtain a modified compound; c. Pelletizing the compound of step (b) through a twin or single-screw extruder to pelletize to obtain pellets or granules or biopolymer; d. Moulding the pelletized compound of step (c) through conventional injection moulding machine at 160°C-185°C to get the final biopolymer for injection moulding applications.

[0052] As per one embodiment the home compostable biopolymer for injection moulding of the present invention, wherein said home compostable biopolymer suitable for the preparation of products including but not limited to cutlery products such as spoons, forks and knives.

[0053] As per one embodiment of the present invention, the home compostable biopolymer for injection moulding can be used in the preparation of products including but not limited to cutlery products such as spoons, forks and knives. The invention is further illustrated by the following examples which are provided to be exemplary of the invention and do not limit the scope of the invention. While the present invention has been described in terms of its specific embodiments, certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the present invention.

[0054] EXAMPLES

[0055] EXAMPLE 1: COMPOSITION OF A HOME COMPOSTABLE

[0056] BIOPOLYMER FOR INJECTION MOULDING Table 1: Composition of home compostable biopolymer for injection moulding

[0057] EXAMPLES 2: PROCESS OF PREPARING THE HOME COMPOSTABLE BIOPOLYMER FOR INJECTION MOULDING The process of preparing the home compostable biopolymer for injection moulding, comprising the following steps: a. Starch, lubricant, compostable polyester resin, and all processing aids was mixed in high-speed mixers at 800 RPM heats it up to 120°C until moisture was removed to obtain a homogenous mixture; b. The homogenous mixture of step (a) is added to screw machine at a feed rate of 500 grams / hour to obtain a modified compound; c. The compound of step (b) was palletised through a twin or single-screw extruder to obtain pellets or granules or biopolymer. d. The pelletized compound of step (c) was moulded through conventional injection moulding machine at 160°C-185°C to get the final biopolymer for injection moulding applications.

[0058] Five different trial batches, designated as Bl, B2, B3, B4, and B5, were prepared using the process described above, and are further exemplified as follows.

[0059] EXAMPLE 3: TRIAL BATCHES OF A HOME COMPOSTABLE

[0060] BIOPOLYMER FOR INJECTION MOULDING

[0061] The trials were performed for the selection of the quantity of the components used are as shown in below table:

[0062] Tab e 2: Trial batches of home compostable biopolymer for injection moulding As shown in Table 2, the trail batch for selecting components for home compostable biopolymer for injection moulding was prepared using the process described in Example 2. Sample of all batches are placed in soil for six months at 53% relative humidity weight loss of organic mass will be equal to or greater than 90%.

[0063] EXAMPLE 4: EVALUATION OF A HOME COMPOSTABLE

[0064] BIOPOLYMER FOR INJECTION MOULDING Table 3: Evaluation of a home compostable biopolymer for injection moulding Result:

[0065] The results highlight significant variations in processability, strength, flexibility, and thermal stability among the batches.

[0066] Batch Bl shows, very high MFI (25) — excellent fill but risks over packing, lower dimensional control. High elongation but slightly higher Tm.

[0067] Batch B2 shows, balanced MFI (18), low Tm (140 °C), acceptable TS and ductility, easy processing —> recommended.

[0068] Batch B3 shows low MFI (10) — harder to fill; moderate mechanicals but processing labelled “moderate.”

[0069] Batch B4 shows MFI 20, Tm 150 °C, “moderate” processing — higher Tm increases cycle time / energy; not as balanced.

[0070] Batch B5 shows MFI 13 and uncertain processing note — inconsistent evidence and lower flow than B2.

[0071] Among the tested batches, batch B2 is identified as the most optimized formulation for conventional injection moulding due to its balanced melt flow index (18 g / 10 min), lower melting temperature (140°C), and easy processability. It provides a good compromise between mechanical strength (18 MPa) and elongation (35%), ensuring smooth mould filling, reduced energy consumption, and stable mechanical properties. Compared to other batches, B2 offers better flow than B3 / B5, lower thermal load than B 1 / B4, and consistent performance, making it the most suitable and efficient batch for injection moulding applications.

[0072] EXAMPLE 5: OPTIMIZED BATCH OF A HOME COMPOSTABLE BIOPOLYMER FOR INJECTION MOULDING As discussed in the results, batch B2 was selected as an optimized batch for preparing a home compostable biopolymer for injection moulding. EXAMPLE 5: COMPARATIVE STUDY

[0073] A comparative batch of 70 parts PLA, 30 parts talc, and 1-part chain extender was prepared by mixing in a high-speed mixture and compounded in a twin screw extruder at 170-190 degrees Celsius, followed by injection molding to make dog bone shape tensile specimens, as shown below. Table 5: Evaluation of comparative batch

[0074] As shown in table 5, the results show that the comparative batch is not home compostable. Conclusion:

[0075] A home compostable biopolymer for injection for conventional injection moulding, offering an ideal balance between processability and mechanical performance. Its moderate melt flow index, lower melting temperature, and easy moulding behavior ensure efficient processing with reduced energy consumption and stable product quality. Overall, it shows superior suitability for injection moulding compared to other trial batches.

[0076] Also, as per the comparative study, a batch consisting of PLA, Talc, and a chain extender is analyzed against a home compostable biopolymer for injection molding made with starch, compostable polyester resin (PBAT / PBS), calcium carbonate, stearic acid, and epoxidized soybean oil. The findings indicate that the comparative batch is not home compostable. In contrast, the home compostable biopolymer demonstrates significant compostability, as evidenced by a weight loss of organic mass equal to or greater than 90% after being placed in soil for six months under conditions of 53% relative humidity, confirming that the present invention qualifies as home compostable.

Claims

Claims,We Claim1. A home compostable biopolymer for injection moulding, wherein biopolymer comprises starch, compostable polyester resin, natural fillers, lubricant and compatibilizer.

2. The home compostable biopolymer for injection moulding as claimed in claim 1, wherein said starch is used in the range of 1-50 parts, more preferably 5-40 parts, and most preferably 15-35 parts.

3. The home compostable biopolymer for injection moulding as claimed in claim 1, wherein said compostable polyester resin is selected from but not limited to polybutylene adipate terephthalate, polyhydroxybutyrate, polyhydroxyalkalonates, polybutylene succinate polyhydroxyhexanoate, polyethylene terephthalateand polycaprolactone.

4. The home compostable biopolymer for injection moulding 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 injection moulding as claimed in claim 1, wherein said lubricant is selected from but not limited to amide organic compounds, stearic acid, wax, vegetable oil and n-butyl stearate.

6. The home compostable biopolymer for injection moulding as claimed in claim 1, wherein said compatibilizer is selected from but not limited to citric acid, maleic anhydride, tween 80, epoxidized vegetable oils, biodegradable polyester, polyhydric fatty ester and polyhydric fatty acid white oil and / or mineral oil.

7. The home compostable biopolymer for injection moulding as claimed in claim 1, wherein said biopolymer comprises: a. 1-50 parts, more preferably 5-35 parts, and most preferably 15-30 parts of starch; b. 10-70 parts, more preferably 10-65 parts and most preferably in 10-55 parts of compostable polyester resin,c. 1-50 parts of natural fillers, more preferably of 10-40 parts natural fillers, and most preferably of 15-25 parts natural fillers; d. 0.1 to 10 parts, more preferably 0.2 to 5 parts and 0.3 to 3 parts of lubricant; and e. 0.1 to 10 parts, more preferably 0.2 to 5 parts and 0.3 to 3 parts of compatibilizer.

8. The process of preparing the home compostable biopolymer for injection moulding as claimed in claim 1, comprising the following steps: a. Mixing starch, lubricant, compostable polyester resin, and all processing aids in high-speed mixers at 800 RPM heats it up to 120°C until moisture is removed to obtain a homogenous mixture; b. Adding the homogenous mixture of step (a) to screw machine at a feed rate of 500 grams / hour to obtain a modified compound; c. Pelletizing the compound of step (b) through a twin or single-screw extruder to obtain the pellets or granules or biopolymer; d. Moulding the pelletized pellets or granules or biopolymer compound of step (c) through conventional injection moulding machine at 160°C-185°C to get the final biopolymer for injection moulding applications.

9. The home compostable biopolymer for injection moulding as claimed in claim 1, wherein said home compostable biopolymer suitable for the preparation of products including but not limited to cutlery products such as spoons, forks and knives.

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