DESC:FIELD
The present disclosure relates to a lignocellulosic composite based thermoplastic composition and a process for its preparation.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Melt Flow Index (MFI): The term “Melt Flow Index” refers to a measure of the ease of flow of the melt of a thermoplastic polymer. It is defined as the weight of the polymer in grams flowing in 10 min through a die of specific diameter and length by a pressure applied by a given weight at a given temperature.
Flexural strength: The term “Flexural strength” refers to a property to measure the ability of the material to withstand at bending forces applied perpendicular to its longitudinal axis.
Heat deflection temperature (HDT): The term “Heat deflection temperature (HDT) also known as heat distortion temperature” refers to the temperature at which a polymer or plastic sample deforms under a specified load.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Lignocellulosic materials have been examined as natural alternative resources obtained from crops and agricultural residues as replacement to petroleum-derived products in different fields due to their inexhaustible supplies and affordable production costs.
In the feedstock, lignocellulosic materials mainly consist of carbohydrate (cellulose and hemicellulose) and aromatic biopolymers (lignin) that have intrinsically complex structures with several properties such as biodegradability, biocompatibility, versatile chemical accessibility and the like. The lignocellulosic materials are widely used in a broad spectrum of structural as well as non-structural applications such as electronic, aerospace, building and construction, furniture, sports goods and the like.
Conventionally, industries are using expensive additive materials to improve the properties of thermoplastic compositions. However, such thermoplastic compositions are required to be available at competitive prices, while conserving materials and shortening process times.
Conventionally, the method for manufacturing thermoplastic compositions by using synthetic fiber is known. These conventional thermoplastic compositions are manufactured either by injection or compression or injection-compression moulding. However, the synthetic fibers used for the preparation of the thermoplastic compositions are not eco-friendly.
Therefore, there is felt a need to provide a lignocellulosic composite based thermoplastic composition and a process for preparing the same that obviates the drawbacks mentioned herein above or at least provides an alternative solution.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
An object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
Yet another object of the present disclosure is to provide a lignocellulosic composite based thermoplastic composition.
Still another object of the present disclosure is to provide a lignocellulosic composite based thermoplastic composition that utilizes natural fiber reinforcements to reduce melt flow index.
Yet another object of the present disclosure is to provide a lignocellulosic composite based thermoplastic composition that is used in automobile applications.
Another object of the present disclosure is to provide a lignocellulosic composite based thermoplastic composition that is eco-friendly and cost effective.
Still another object of the present disclosure is to provide a simple and environment friendly process for the preparation of a lignocellulosic composite based thermoplastic composition.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a lignocellulose composite based thermoplastic composition and a process for its preparation.
In an aspect, the present disclosure relates to a lignocellulose composite based thermoplastic composition. The lignocellulose composite based thermoplastic composition comprises a thermoplastic polymer; natural reinforcing fibers; a coupling agent; an impact modifier; a flame retardant; metal stearates; and optionally; coconut dust.
In accordance with the present disclosure, the thermoplastic polymer is present in an amount in the range of 50 mass % to 65 mass % with respect to the total amount of the composition.
In accordance with the present disclosure, the natural reinforcing fibers are present in an amount in the range of 15 mass % to 25 mass % with respect to the total amount of the composition.
In accordance with the present disclosure, the coconut dust is present in an amount in the range of 0 mass % to 2.5 mass % with respect to the total amount of the composition.
In accordance with the present disclosure, the coupling agent is present in an amount in the range of 2 mass % to 10 mass % with respect to the total amount of the composition.
In accordance with the present disclosure, the impact modifier is present in an amount in the range of 5 mass % to 15 mass % with respect to the total amount of the composition.
In accordance with the present disclosure, the flame retardant is present in an amount in the range of 2 mass % to 10 mass % with respect to the total amount of the composition.
In accordance with the present disclosure, the metal stearates are present in an amount in the range of 0.5 mass% to 2 mass% with respect to the total amount of the composition.
In accordance with the present disclosure, the thermoplastic polymer is at least one selected from polypropylene (PP), and polyethylene (PE).
In accordance with the present disclosure, the natural reinforcing fibers are at least one selected from the group consisting of bamboo fibers, sisal fibers, flax fibers, hemp fibers and wood fibers.
In accordance with the present disclosure, the coconut dust is at least one selected from the group consisting of coir fiber powder, and coco peat.
In accordance with the present disclosure, the coupling agent is at least one selected from the group consisting of maleic anhydride-grafted polypropylene (MAPP), and organosilanes.
In accordance with the present disclosure, the impact modifier is at least one selected from the group consisting of ethylene propylene diene monomer (EPDM) rubber, vinyl rubber and thermoplastic elastomer.
In accordance with the present disclosure, the flame retardant is at least one selected from the group consisting of phenol, phosphates and aluminium trihydrate (ATH); and
In accordance with the present disclosure, the metal stearates is at least two select from calcium stearate, zinc stearate, magnesium stearate and aluminum stearate; and wherein a mass ratio of the at least two metal stearates is in the range of 3:1 to 1:3.
In accordance with the present disclosure, the composition is characterized by having:
a density is in the range of 0.95 g/cc to 1 g/cc, when measured as per ASTM D792 standard;
MFI at 230 °C is in the range of 9 g/10 min to 11 g/10 min, when measured as per ASTM D1238 standard;
a melting point in the range of 160 °C to 170 °C, when measured as per ASTM D3418 standard;
a crystallization point in the range of 115 °C to 125 °C, when measured as per ASTM D3418 standard; and
a degradation temperature in the range of 450 °C to 470 °C, when measured as per ASTM E1131 standard.

In another aspect, the present disclosure relates to a process for preparation of lignocellulose composite based thermoplastic composition. The process comprises treating predetermined amounts of natural reinforcing fibers with alkali solution at a first predetermined temperature for a first predetermined time period to obtain treated fibers. The treated fibers are washed with water followed by cutting to obtain fibers having predetermined size. Optionally, separately a predetermined amount of coconut dust is obtained and mixed with fibers followed by drying at second predetermined temperature for a time period in the range of 30 minutes to 45 minutes to obtain a resultant mixture. Predetermined amounts of at least one thermoplastic polymer, at least one coupling agent, at least one impact modifier, at least one flame retardant and at least two metal stearates are added in the resultant mixture or the fibers followed by mixing in a extruder at a third predetermined temperature at a predetermined torque and a predetermined speed to obtain the lignocellulosic composite based thermoplastic composition.
In accordance with the present disclosure, the alkali solution is at least one selected from caustic soda solution (NaOH), potassium hydroxide (KOH) solution, and calcium hydroxide (Ca(OH)2); and wherein the alkali solution have a concentration in the range of 0.3 N to 0.8 N.
In accordance with the present disclosure, the predetermined size is in the range of 0.5 mm to 2 mm.
In accordance with the present disclosure, the first predetermined temperature is in the range of 25 °C to 35 °C.
In accordance with the present disclosure, the second predetermined temperature is in the range of 40 °C to 80 °C.
In accordance with the present disclosure, the third predetermined temperature is in the range of 170 °C to 210 °C.
In accordance with the present disclosure, the first predetermined time period is in the range of 20 minutes to 40 minutes.
In accordance with the present disclosure, the predetermined torque is in the range of 60 Nm to 80 Nm.
In accordance with the present disclosure, the predetermined speed is in the range of 160 rpm to 200 rpm.
Still in another aspect the present disclosure provides an article made by using the composition. The article is characterized by having:
tensile strength in the range of 20 MPa to 40 MPa; when measured as per ASTM D 638 standard;
tensile modulus in the range of 1760 MPa to 1840 MPa; when measured as per ASTM D 638 standard;
flexural strength in the range of 20 MPa to 60 MPa, when measured as per ASTM D790 standard;
flexural modulus in the range of 2200 MPa to 2400 MPa, when measured as per ASTM D790 standard;
heat deflection temperature at 0.45 MPa in the range of 120 °C to 150 °C, when measured as per ASTM D 648 standard;
notched impact strength at 23 °C in the range of 50 J/m to 65 J/m, when measured as per ASTM S256; and
mold shrinkage in the range of 2% to 3%, when measured as per ASTM D 955.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a flow chart of the method of preparing the lignocellulose based composite thermoplastic composition in accordance with the present disclosure; and
FIGURE 2 illustrates the pictorial representation of the interfacial adhesion between thermoplastic polymer (PP), coupling agent (MAPP), natural reinforcing fibers (bamboo fiber) and flame retardant (ATH) through the formation of an ester linkage at the interface.
DETAILED DESCRIPTION
The present disclosure relates to a lignocellulose composite based thermoplastic composition and a process for its preparation.
Embodiments of the present disclosure will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Conventionally, the method for manufacturing thermoplastic composition by using synthetic fiber is known. These conventional thermoplastic compositions are manufactured either by injection or compression or injection-compression moulding. However, the synthetic fibers used for the preparation of the thermoplastic compositions are not eco-friendly.
The present disclosure provides a lignocellulose composite based thermoplastic composition and a process for its preparation.
In an aspect of the present disclosure, the lignocellulose composite based thermoplastic composition comprises a thermoplastic polymer; natural reinforcing fibers; a coupling agent; an impact modifier; a flame retardant; metal stearates; and optionally, coconut dust.
In an embodiment of the present disclosure, the thermoplastic polymer is present in an amount in the range of 50 mass % to 65 mass % with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the thermoplastic polymer is present in an amount of 61 mass % based with respect to the total mass of the composition. In another exemplary embodiment of the present disclosure, the thermoplastic polymer is present in an amount of 56 mass % with respect to the total mass of the composition.
In an embodiment of the present disclosure, the natural reinforcing fibers is present in an amount in the range of 15 mass % to 25 mass % with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the bamboo fibers are present in an amount of 20 mass % with respect to the total mass of the composition.
In an embodiment of the present disclosure, the coconut dust is present in an amount in the range of 0 mass % to 2.5 mass % with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the coconut dust is present in an amount of 1 mass % with respect to the total mass of the composition.
In an embodiment of the present disclosure, the coupling agent is present in an amount in the range of 2 mass % to 10 mass % with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the coupling agent is present in an amount of 5 mass % with respect to the total mass of the composition.
In an embodiment of the present disclosure, the impact modifier is present in an amount in the range of 5 mass % to 15 mass % with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the impact modifier is present in an amount of 10 mass % with respect to the total mass of the composition. In another exemplary embodiment of the present disclosure, the impact modifier is present in an amount of 12 mass % with respect to the total mass of the composition.
In an embodiment of the present disclosure, the flame retardant is present in an amount in the range of 2 mass % to 10 mass % with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the flame retardant is present in an amount of 3 mass % with respect to the total mass of the composition.
In an embodiment of the present disclosure, the metal stearates are present in an amount in the range of 0.5 mass% to 2 mass% with respect to total amount of the composition. In an exemplary embodiment of the present disclosure, the metal stearates are present in an amount of 1 mass% with respect to the total amount of the composition.
In accordance with the present disclosure, the metal stearates is at least two selected from the group consisting of calcium stearate, zinc stearate, magnesium stearate and aluminum stearate. In an exemplary embodiment, the at least two metals stearates are calcium stearate and zinc stearate.
In an embodiment of the present disclosure, the ratio of calcium stearate to zinc stearate is in the range of 3:1 to 1:3. In an exemplary embodiment, the ratio of calcium stearate to zinc stearate is 1:1.
In an embodiment of the present disclosure, the thermoplastic polymer is at least one selected from polypropylene (PP) and polyethylene (PE). In an exemplary embodiment, the thermoplastic polymer is polypropylene (PP).
In an embodiment of the present disclosure, the natural reinforcing fibers are at least one selected from the group consisting of bamboo fibers, sisal fibers, flax fibers, hemp fibers and wood fibers. In an exemplary embodiment, the natural reinforcing fibers are bamboo fibers.
Bamboo fibers are derived from the stems of bamboo plants, which belong to the grass family. Bamboos are grown widely in Asian countries. As a fiber, bamboo is a natural cellulosic regenerated biodegradable environment friendly textile fiber. It is a green fiber and has inherent anti- bacterial and UV protective property.
Sisal fibers are obtained from Sisal plants. Sisal fibers are derived from the leaves of the Sisal plants. Sisal plants belong to Agave Sisalana species and Asparagaceae family. It has the origin from southern Mexico, now it is cultivated in many other countries. The Sisal fibers yields a stiff fiber which can be used for making products such as rope, twine and the like. It is also used for making products such as paper, cloth, footwear, hats, bags, carpets, geotextiles, dartboards and the like. It is also used as fiber reinforcements for composite fiberglass, rubber, and concrete products.
Flax fibers are obtained from Flax plants. Flax fibers are derived from the stems of the flax plant (Linum usitatissimum).Flax is also known as common flax or linseed. It is a flowering plant, and belongs to the Linaceae family. Flax fibers are extracted from the surface of the stem of the flax plant. Flax fibers are soft, lustrous, and flexible. The flax fibers are stronger than cotton fiber, but are less elastic.
Hemp fibers are obtained from the Hemp plants. Hemp plants belong to Cannabis sativa class. It can be used in variety of application such as paper, rope, textiles, clothing, biodegradable plastics, and the like. The Hemp fibers have high strength and durability.
Wood fibers are the cellulosic materials extracted from trees.
In an embodiment of the present disclosure, the coconut dust is at least one selected from coir fiber powder, and coco peat. In an exemplary embodiment, the coconut dust is coco peat.
Coir fibers are the coconut fibres. It is a natural fibre that is extracted from the outer husk of coconut. The Austronesian peoples, first domesticated coconuts and used the coconut fibre for making ropes and building houses and boats. The coir fibres are found between the hard internal shell and the outer coat of a coconut. The individual coir fibre cells are narrow and hollow, made of cellulose.
Coco peat can be referred as either to coir or the pith or a mixture of both.
In an embodiment of the present disclosure, the coupling agent is at least one selected from maleic anhydride-grafted polypropylene (MAPP), and organosilanes. In an exemplary embodiment, the coupling agent is maleic anhydride-grafted polypropylene (MAPP).
In an embodiment of the present disclosure, the impact modifier is at least one selected from the group consisting of ethylene propylene diene monomer (EPDM) rubber, vinyl rubber and thermoplastic elastomer. In an exemplary embodiment, the impact modifier is ethylene propylene diene monomer (EPDM) rubber.
In an embodiment of the present disclosure, the flame retardant is at least one selected from the group consisting of phenol, phosphates and aluminium trihydrate (ATH). In an exemplary embodiment, the flame retardant is aluminium trihydrate (ATH). In another exemplary embodiment, the flame retardant is phenol/phosphate based flame retardant
In an embodiment of the present disclosure, the phenol based flame retardant consists of 17 mass% to 21 mass% nitrogen content and 18 mass% to 22 mass% phosphorus content. In still another embodiment of the present disclosure, the flame retardant is alumina trihydrate (ATH) of 99.8 % purity and 2.42 g/cc of density.
In an embodiment of the present disclosure, metal stearates is at least one select from calcium stearate, zinc stearate, magnesium sterate and aluminium stearate. In an exemplary embodiment, the metal stearate is a combination of calcium stearate and zinc stearate.
In an embodiment of the present disclosure, the mass ratio of the at least two metal stearates is in the range of 3:1 to 1:3. In an exemplary embodiment of the present disclosure, the mass ratio of the at least two metal stearates is 1:1.
In an embodiment of the present disclosure, the lignocellulose composite based thermoplastic composition is characterized by having:
density in the range of 0.95 g/cc to 1 g/cc, when measured as per ASTM D 792 standard;
MFI at 230 °C is in the range of 9 g/10 min to 11 g/10 min, when measured as per ASTM D 1238 standard;
melting point in the range of 160 °C to 170 °C, when measured as per ASTM D 3418 standard;
crystallization point in the range of 115 °C to 125 °C, when measured as per ASTM D 3418 standard; and
degradation temperature in the range of 450 °C to 470 °C, when measured as per ASTM E 1131 standard.
In an exemplary embodiment, the composition is characterized by having:
density of 0.99 g/cc, when measured as per ASTM D 792 standard;
MFI at 230 °C of 10.926 g/10 min, when measured as per ASTM D 1238 standard;
melting point of 166.50 °C, when measured as per ASTM D 3418 standard;
crystallization point of 120.45 °C, when measured as per ASTM D 3418 standard; and
degradation temperature of 456.41 °C, when measured as per ASTM E 1131 standard.
In another exemplary embodiment, the composition is characterized by having:
density of 0.97 g/cc, when measured as per ASTM D 798 standard;
MFI at 230 °C of 9.036 g/10 min, when measured as per ASTM D 1238 standard;
melting point of 165.43 °C, when measured as per ASTM D 3418 standard;
crystallization point of 119.49 °C, when measured as per ASTM D 3418 standard; and
degradation temperature of 463.58 °C, when measured as per ASTM E 1131 standard.
The lignocellulosic composite based thermoplastic composition exhibits a reduced melt flow index and is suitable for automobile applications.
The lignocellulose composite based thermoplastic composition uses renewable materials for automobile applications. The lignocellulose composite based thermoplastic composition is eco-friendly and cost-effective.
In another aspect, the present disclosure provides a process for the preparation of a lignocellulose composite based thermoplastic composition.
The process comprising the following steps:
treating predetermined amounts of natural reinforcing fibers with alkali solution at a first predetermined temperature for a first predetermined time period to obtain treated fibers;
washing the treated fibers with water followed by cutting to obtain fibers having a predetermined size;
optionally, separately obtaining a predetermined amount of coconut dust and mixing with said fibers followed by drying at a second predetermined temperature for a time period in the range of 30 minutes to 45 minutes to obtain a resultant mixture; and
adding predetermined amounts of at least one thermoplastic polymer, at least one coupling agent, at least one impact modifier, at least one flame retardant and at least two metal stearates in the resultant mixture or fibers followed by mixing in a extruder at a third predetermined temperature at a predetermined torque and at a predetermined speed to obtain the lignocellulosic composite based thermoplastic composition.
The process is described in detail.
In a first step, a predetermined amount of natural reinforcing fibers are treated with alkali solution at first predetermined temperature for a first predetermined time period to obtain treated fibers.
In an embodiment of the present disclosure, the natural reinforcing fibers are at least one selected from the group consisting of bamboo fibers, sisal fibers, flax fibers, hemp fibers and wood fibers. In an exemplary embodiment, the natural reinforcing fibers are bamboo fibers.
In an embodiment of the present disclosure, the natural reinforcing fibers are present in an amount in the range of 15 mass% to 25 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the bamboo fibers are present in an amount of 20 mass% with respect to the total mass of the composition.
Natural reinforcing fibers such as bamboo, hemp, jute, and flax, provide reinforcement and improve the mechanical properties of the lignocellulosic composite based thermoplastic composition. The natural reinforcing fibers are renewable, biodegradable, and have a lower density compared to traditional synthetic fibers. Further, the natural reinforcing fibers offer advantages such as high specific strength, good thermal insulation, reduced energy consumption during processing, and have lower environmental impact.
The natural reinforcing fibers help to increase the tensile and flexural properties. Further, the natural reinforcing fibers help to increase the modulus of the thermoplastic polymer composition that is comparable with the commercially available polymers used in automobile applications.
In an embodiment of the present disclosure, the 1. alkali solution is at least one selected from caustic soda solution (NaOH), potassium hydroxide (KOH) solution, and calcium hydroxide (Ca(OH)2); and wherein the alkali solution have a concentration in the range of 0.3 N to 0.8 N. In an exemplary embodiment, the alkali solution is caustic soda solution having a concentration of 0.5 N.
In an embodiment of the present disclosure, the alkali solution is used in an amount in the range of 0.2 mass% to 2 mass%. In an exemplary embodiment, the alkali solution is used in an amount of 1 mass%.
The chemical reaction between the natural reinforcing fibers and alkali solution is as represented by reaction (I)
Fiber-OH+NaOH ?Fiber-O^- ?Na?^++H_2 O……………………………. (I)
In an embodiment of the present disclosure, the first predetermined temperature is in the range of 25 °C to 35 °C (room temperature). In an exemplary embodiment, the first predetermined temperature is 27 °C.
In an embodiment of the present disclosure, the first predetermined time period is in the range of 20 minutes to 40 minutes. In an exemplary embodiment, the first predetermined time period is 30 minutes.
The treated fibers are washed with water followed by cutting to obtain fibers having predetermined size.
In an embodiment of the present disclosure, the washed fibers are fed to a fiber cutting machine followed by sieving to obtain fibers having predetermined size.
In an embodiment of the present disclosure, the treated fibers are washed to obtain washed fibers.
In an embodiment of the present disclosure, the predetermined size is in the range of 0.5 mm to 2 mm. In an exemplary embodiment, the predetermined size is 1 mm.
optionally, separately obtaining a predetermined amount of coconut dust and mixing with the fibers followed by drying at a second predetermined temperature for a time period in the range of 30 minutes to 45 minutes to obtain a resultant mixture; and.
In an embodiment of the present disclosure, the coco peat is sieved through mesh in the range from 200 micron metallic mesh to 300 micron metallic mesh to obtain coconut dust. In an exemplary embodiment, the coco peat is sieved through 250 micron metallic mesh to obtain coconut dust.
In an embodiment of the present disclosure, the coconut dust is at least one selected from coir fiber powder, and coco peat. In an exemplary embodiment, the coconut dust is a natural fibre.
In an embodiment of the present disclosure, the coconut dust is present in an amount in the range of 0 mass% to 2.5 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the coconut dust is present in an amount of 1 mass% with respect to the total mass of the composition.
The coconut dust is mixed with the fibers followed by drying at a second predetermined temperature for a time period in the range of 30 minutes to 45 minutes to obtain a resultant mixture.
Coconut dust is a waste byproduct of coconut processing. It offers an attractive alternative to synthetic binders. The high lignin content in coconut dust provides adhesive properties, allowing it to effectively bind the bamboo fibers and the thermoplastic polypropylene. The lignin acts as a natural adhesive, improving the interfacial adhesion between the components, thereby enhancing the mechanical properties of the thermoplastic composition.
MFI of ~10 is generally considered optimal for injection molding because it strikes a balance between flowability and process control, which allows it to fill the mold cavity effectively.
Coconut dust along with the natural reinforcing fibers, when added to the thermoplastic polymer, can reduce the MFI of the lignocellulosic composite based thermoplastic composition. The high lignin content in coconut dust acts as a natural binder, improving the interfacial adhesion between the bamboo fibers (natural reinforcing fibers) and the PP thermoplastic. This enhanced bonding reduces the mobility of the polymer chains during the melting process, resulting in increased viscosity and decreased MFI.
Reducing the MFI through the addition of coconut dust improves the processability of the lignocellulosic composite based thermoplastic composition during injection molding. A lower MFI indicates the material flows more slowly and with greater control, allowing for improved filling of intricate mold features and reducing the likelihood of defects like voids or incomplete filling. It provides the processor with greater control over the molding process and enhances the overall quality of the molded product.
The addition of coconut dust as a binder in the lignocellulosic composite based thermoplastic composition also improves the interfacial adhesion between the fibers and the thermoplastic. This improved interfacial bonding leads to enhanced mechanical properties, such as increased tensile strength, flexural strength, and impact resistance.
Further, using coconut dust as a natural binder in the lignocellulosic composite based thermoplastic composition offers additional environmental benefits. Coconut dust is a waste byproduct of coconut processing, making it a sustainable and renewable resource. By incorporating coconut dust, the overall composition of the composite can include a significant portion of renewable and biodegradable materials, reducing reliance on non-renewable resources and minimizing environmental impact.
In an embodiment of the present disclosure, the second predetermined temperature is in the range of 40 °C to 80 °C. In an exemplary embodiment, the second predetermined temperature is 60 °C.
In an embodiment of the present disclosure, the thermoplastic polymer is at least one selected from polypropylene (PP) and polyethylene (PE). In an exemplary embodiment, the thermoplastic polymer is polypropylene (PP).
Thermoplastic polymers, such as polypropylene (PP) and polyethylene (PE) offer several advantages such as excellent processability, high mechanical strength, good chemical resistance, and wide availability.
Thermoplastic polymers can be melted and reprocessed multiple times, making them suitable for various fabrication techniques.
In an embodiment of the present disclosure, the predetermined amount of the thermoplastic polymer is present in an amount in the range of 50 mass% to 65 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the predetermined amount of the thermoplastic polymer is present in an amount of 61 mass% with respect to the total mass of the composition. In another exemplary embodiment of the present disclosure, the predetermined amount of the thermoplastic polymer is present in an amount of 56 mass % with respect to the total mass of the composition.
Thermoplastic polypropylene is the most used commodity plastic made from a combination of propylene monomers and its crystallinity is based on the tacticity of methylene pendant groups along the main chain. It is used in a variety of applications that include household appliances, packaging, electrical equipment manufacturing and transportation thereof.
In an embodiment of the present disclosure, the coupling agent is at least one selected from the group consisting of maleic anhydride-grafted polypropylene (MAPP), and organosilane compounds. In an exemplary embodiment, the coupling agent is maleic anhydride-grafted polypropylene (MAPP).
In an embodiment of the present disclosure, the maleic anhydride grafted polypropylene (PP) with 1 wt% of maleic anhydride, having molecular weight (Mw) of 47,000 and acid number 15 is used as a coupling agent.
In an embodiment of the present disclosure, the predetermined amount of the coupling agent is present in an amount in the range of 2 mass% to10 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the coupling agent is present in an amount of 5 mass% with respect to the total mass of the composition.
Coupling agent is used to enhance the interfacial bonding between the thermoplastic polymer and natural reinforcing fibers. It improves the adhesion and compatibility between different components, enhancing the overall mechanical properties of the lignocellulosic composite based thermoplastic composition. Further, the coupling agents promote the transfer of stress between the thermoplastic polymer and the natural reinforcing fibers, leading to increased strength, stiffness, and durability of the lignocellulosic composite based thermoplastic composition.
In an embodiment of the present disclosure, the impact modifier is at least one selected from the group consisting of ethylene propylene diene monomer (EPDM) rubber, vinyl rubber and thermoplastic elastomer. In an exemplary embodiment, the impact modifier is ethylene propylene diene monomer (EPDM).
In an embodiment of the present disclosure, EPDM (ethylene propylene diene monomer) rubber containing 70% ethylene with 4.9% ENB unsaturation is used as an impact modifier.
In an embodiment of the present disclosure, the predetermined amount of impact modifier is in an amount in the range of 5 mass% to 15 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the impact modifier is present in an amount of 10 mass% with respect to the total mass of the composition. In another exemplary embodiment of the present disclosure, the impact modifier is present in an amount of 12 mass% with respect to the total mass of the composition.
Impact modifiers improve the impact resistance and toughness of the lignocellulosic composite based thermoplastic composition.
In an embodiment of the present disclosure, the flame retardant is at least one selected from the group consisting of phenol, phosphates and aluminium trihydrate (ATH). In an exemplary embodiment, the flame retardant is aluminium trihydrate.
Aluminium trihydrate (Aluminium hydrate/Aluminium hydroxide, Al(OH)3) has significant fire-resistant properties. Aluminium trihydrate is a non-toxic and environmentally friendly flame retardant. It does not release harmful gases or toxic substances when exposed to fire. This makes it suitable for applications where safety and environmental considerations are paramount. Aluminium trihydrate has an endothermic decomposition process, which means it absorbs heat energy during its decomposition. When exposed to fire, aluminium trihydrate decomposes into aluminium oxide (Al2O3) and water (H2O), effectively absorbing heat and reducing the temperature of the surrounding environment.
As aluminium trihydrate decomposes, the released water vapor helps to dilute the flammable gases, reducing their concentration and limiting the spread of flames. The water vapor also acts as a heat sink, absorbing heat and further suppressing the combustion process.
In an embodiment of the present disclosure, the predetermined amount of flame retardant is present in an amount in the range of 2 mass% to 10 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the flame retardant is present in an amount of 3 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the phenol/phosphate based flame retardant consisting nitrogen content in the range of 17 wt% to 21 wt% and phosphorus content in the range of 18 wt% to 22 wt% is used as a flame retardant. ATH of 99.8 % purity and 2.42 g/cc of density is used.
In an embodiment of the present disclosure, the at least two metal stearates are selected from the group consisting of calcium stearate, zinc stearate, magnesium stearate and aluminium stearate. In an exemplary embodiment of the present disclosure, the metal stearate is a mixture of calcium stearate and zinc stearate.
In an embodiment of the present disclosure, the metal stearates are present in an amount in the range of 0.5 mass% to 2 mass% with respect to total amount of the composition. In an exemplary embodiment of the present disclosure, the metal stearates are present in an amount of 1 mass%.
In an embodiment of the present disclosure, a mass ratio of calcium stearate to zinc stearate is in the range of 3:1 to 1:3. In an exemplary embodiment of the present disclosure, the mass ratio of calcium stearate to zinc stearate is 1:1.
In an embodiment of the present disclosure, the third predetermined temperature is in the range of 170 °C to 210 °C. In an exemplary embodiment, the third predetermined temperature is 190 °C.
In an embodiment of the present disclosure, the predetermined torque is in the range of 60 Nm to 80 Nm. In an exemplary embodiment of the present disclosure, the predetermined torque is 70 Nm.
In an embodiment of the present disclosure, the predetermined speed is in the range of 160 rpm to 200 rpm. In an exemplary embodiment of the present disclosure, the predetermined speed is 180 rpm.
In an embodiment of the present disclosure, the mixing is performed by using at least one selected from twin screw extruder and extruder. In an exemplary embodiment, the mixing is performed in a twin screw extruder.
A twin-screw compounder is a versatile extrusion machine used for compounding and melt blending polymer matrices with reinforcing fibers. The process begins by feeding the thermoplastic polymer, natural reinforcing fibers, and coconut dust with all the other processing aids into the feed hopper of the twin-screw compounder. The co-rotating screws within the extruder barrel convey, mix, and melt the materials through the action of shearing and kneading. The bamboo fibers are uniformly dispersed and impregnated with the molten PP matrix, leading to enhanced interfacial adhesion and improved mechanical properties.
Several parameters are optimized during twin-screw compounding, such as screw speed, temperature profile, and residence time. The screw speed determines the conveying and mixing efficiency, while the temperature profile ensures proper melting of the thermoplastic polymer and natural fiber impregnation. Residence time is controlled to achieve adequate mixing and dispersion of natural fiber impregnation within the molten thermoplastic polymer. Process parameters are crucial to achieve uniform distribution of the natural reinforcing fibers, minimize fiber breakage, and maintain the desired properties.
Still in another aspect, the present disclosure provides an article made by using the lignocellulosic composite based thermoplastic composition.
The lignocellulosic composite based thermoplastic composition obtained through twin-screw compounding, is further processed using injection molding to produce articles (test specimens) for testing and evaluation. Injection molding involves injecting the molten composite into a mold cavity under high pressure, followed by cooling and solidification. This process enables the production of complex shapes and precise control over part dimensions. The injection molding process requires the design and fabrication of suitable molds with cavities matching the desired article dimensions. The molten composite material is injected into the mold, filling the cavity completely. After cooling, the mold is opened, and the solidified article is ejected.
The article is characterized by having:
tensile strength in the range of 20 MPa to 40 MPa; when measured as per ASTM D 638 standard;
tensile modulus in the range of 1760 MPa to 1840 MPa; when measured as per ASTM D 638 standard;
flexural strength in the range of 20 MPa to 60 MPa, when measured as per ASTM D790 standard;
flexural modulus in the range of 2200 MPa to 2400 MPa, when measured as per ASTM D790 standard;
heat deflection temperature at 0.45 MPa in the range of 120 °C to 150 °C, when measured as per ASTM D 648 standard;
notched impact strength at 23 °C in the range of 50 J/m to 65 J/m, when measured as per ASTM S256; and
mold shrinkage in the range of 2% to 3%, when measured as per ASTM D 955.
In an exemplary embodiment of the present disclosure, the article is characterized by having:
tensile strength of 27.04 MPa; when measured as per ASTM D 638 standard;
tensile modulus of 1820 MPa; when measured as per ASTM D 638 standard;
flexural strength of 24.83 MPa, when measured as per ASTM D790 standard;
flexural modulus of 2250 MPa, when measured as per ASTM D790 standard;
notched impact strength at 23 °C, of 53.59 J/m, when measured as per ASTM S256;
heat deflection temperature (HDT) at 0.45 MPa, of 130 °C, when measured as per ASTM D 648 standard; and
mold shrinkage of 2.3%, when measured as per ASTM D 955.
In another exemplary embodiment of the present disclosure, the article is characterized by having:
tensile strength of 33.89 MPa; when measured as per ASTM D 638 standard;
tensile modulus of 1796.79 MPa; when measured as per ASTM D 638 standard;
flexural strength of 54.89 MPa, when measured as per ASTM D790 standard;
flexural modulus of 2282.63 MPa, when measured as per ASTM D790 standard;
notched impact strength at 23 °C, of 60.17 J/m, when measured as per ASTM S256;
heat deflection temperature (HDT) at 0.45 MPa, of 144.9 °C, when measured as per ASTM D 648 standard; and
mold shrinkage of 2.4%, when measured as per ASTM D 955.
In accordance with the present disclosure, the lignocellulosic composite based thermoplastic composition utilizes natural reinforcing fibers to reduce melt flow index. The lignocellulosic composite based thermoplastic composition of the present disclosure is used in automobile applications. The lignocellulosic composite based thermoplastic composition of the present disclosure is cost-effective, and eco-friendly.
The lignocellulosic composite based thermoplastic composition of the present disclosure utilizes natural reinforcing fibers which help to improve flexural and thermal properties. The flexural properties of the articles made from the lignocellulosic composite based thermoplastic composition of the present disclosure increase significantly and they are comparable with the commercially available polymers used in automobile applications. The articles also exhibited favorable thermal property for automobile applications. The articles made from the lignocellulosic composite based thermoplastic composition of the present disclosure are cost effective in automobile sector with good strength, light-weight, dimensional stability, stiffness/stability, durable performance and corrosion resistance. The design flexibility for complex shape is another advantage as these lignocellulosic composite based thermoplastic composition can be easily filled in the multi-cavity molds. These lignocellulosic composite based thermoplastic composition also reduce operating costs and improve efficiency owing to their light weight.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment but are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
Experiment 1: Process for the preparation of the lignocellulosic composite based thermoplastic composition by using coconut dust in accordance with the present disclosure.
20 gm of bamboo fibers (natural reinforcing fibers) were treated with 100 ml of 0.5 N sodium hydroxide solution (alkali solution) at 27 °C (room temperature) (first predetermined temperature) for 30 minutes (first predetermined time period) to obtain treated fibers. The so obtained treated fibers were washed with water to obtain washed fibers. The washed fibers were fed in a cutting machine followed by sieving to obtain fibers of 1 mm size.
Separately, coconut dust was sieved through 250 micron metallic mesh to obtain 1 gm of coconut dust. The so obtained coconut dust was mixed with the fibers (1 mm) followed by drying at 60 °C (second predetermined temperature) for 40 minutes to obtain a resultant mixture.
61 gm of polypropylene (PP) (thermoplastic polymer), 5 gm of maleic anhydride-grafted polypropylene (MAPP) (coupling agent), 10 gm of ethylene propylene diene monomer (EPDM) (impact modifier), 3 gm of aluminium trihydrate (flame retardant), 0.5 gm of calcium stearate, 0.5 gm of zinc stearate were added to the resultant mixture followed by mixing and extruding in a twin screw extruder at 190 °C (third predetermined temperature) at 70 Nm (predetermined torque) and at 180 rpm (predetermined speed) to obtain the lignocellulosic composite based thermoplastic composition (composition 1).
Figure 1 demonstrates a flow chart of the method of preparing the lignocellulose based composite thermoplastic composition in accordance with the present disclosure.
Experiment No 2: Process for the preparation of the lignocellulosic composite based thermoplastic composition without using coconut dust in accordance with the present disclosure.
The composition 2 was prepared by the similar process as experiment 1 by varying the proportion of the components and by using phenol/phosphate flame retardant instead of ATH flame retardant. Further, coconut dust was not used in composition 2.
Table 1 illustrates the composition 1 and composition 2 prepared in accordance with the present disclosure.
Materials Composition 1
(mass %) Composition 2
(mass %)
Polypropylene 56 61
Bamboo fiber 20 20
Coconut dust 1 -
Maleic anhydride-grafted polypropylene (MAPP) 5 5
Ethylene propylene diene monomer (EPDM) 12 10
Phenol/Phosphate -- 5
Aluminium trihydrate (ATH) 3 --
Calcium stearate 0.5 0.5
Zinc Stearate 0.5 0.5
From table 1 it is observed that the, composition 1 and composition 2 differs with respect to the components. Composition 1 comprises some additives which were not included in composition 2. In specific, the materials such as coconut dust and aluminium trihydrate were used in composition 1. The polypropylene (PP) with a density of 0.915 g/cc and melt flow index in the range of 11g/10 minutes to 12 g/10 minutes was used.
Characterization of the lignocellulosic composite based thermoplastic composition prepared in accordance with the present disclosure and the comparative example.
The lignocellulosic composite based thermoplastic composition obtained in experiment 1/2 was subjected for a characterization of the properties such as density, MFI, melting point, crystallization point and maximum degradation temperature. The density was measured by using density meter as per ASTM D792, MFI was measured by using melt flow indexer as per ASTM D1238, melting point was measured by using differential scanning calorimeter (DSC) as per ASTM D3418, crystallization point was measured by using differential scanning calorimeter (DSC) as per ASTM D3418, and maximum degradation temperature was measured by using thermogravimetry (TGA) as per ASTM E1131.
The MRPL Mangpol PP HM120T is referred as the comparative thermoplastic composition (comparative example). It comprises 100% polypropylene.
Table 2 illustrates the physico-mechanical and thermal properties of the composition 1, the composition 2 prepared in accordance with the present disclosure and the comparative composition with units.
Sr.No Properties Units Test Standard Composition 1 Composition 2 Comparative composition
(MANGPOL PP HM120T)
1. Density g/cc ASTM D792 0.97 0.99 0.91
2. MFI at 230 °C g/10min ASTM D 1238 9.036 10.926 12
3. Melting point ° C ASTM D3418 165.43 166.50 167.17
4. Crystallization point ° C ASTM D3418 119.49 120.45 120
5. Maximum degradation temperature ° C ASTM E1131 463.58 456.41 420.98
From table 2 it is evident that the compositions of the present disclosure has comparatively improved melt flow index (MFI) and maximum degradation temperature as compared to the comparative composition. Further, the melting point and the crystallization point are comparable with the MANGPOL PP HM120T (Comparative composition). The composition of the present disclosure comprises the byproduct such as coconut dust, biodegradable material such as natural reinforcing fibers still it provides improved/comparable properties as compared to MANGPOL PP HM120T (Comparative composition).
Physico-Mechanical and Thermal Properties of the articles prepared in accordance with the present disclosure.
To evaluate the mechanical properties, articles (test specimens) were prepared using the lignocellulosic composite based thermoplastic composition of the present disclosure.
The articles (test specimen) were prepared as per ASTM D 3641 standard by counter-rotating the lignocellulosic composite based thermoplastic composition in a twin screw micro compounder and microinjection jet at 200 °C and injection pressure of 6 bars.
Table 3 illustrates the physico-mechanical and thermal properties of the articles prepared by the composition of the present disclosure and comparative composition with units.
Sr.No Properties Units Test Standard Article/test
specimen 1 Article/test
specimen 2 Comparative article/test specimen
Tensile Strength MPa ASTM D 638 27.04±5 33.89 ± 0.18 33
Tensile Modulus MPa ASTM D 638 1820±20 1796.79±27 1800
. Flexural Strength MPa ASTM D 790 24.89±4 54.89 ± 2.36 41
Flexural Modulus MPa ASTM D 790 2250±20 2282.63 ±112 1800
. Notched Impact strength at 23 °C J/m ASTM D 256 53.59±3 60.17 ± 2 18
. HDT at 0.45 MPa ° C ASTM D 648 130±5 144.9 ± 0.6 85
Mold Shrinkage % ASTM D 955 2.3 2.4 5
From table 3 it is evident that the composition of the present disclosure has improved interfacial balance due to the increased mechanical strength as compared to the comparative composition. In particular, the impact strength of the composition of the present disclosure is 32 % higher than the comparative composition. Further, heat deflection temperature (HDT) of the present disclosure is higher than the comparative composition. The difference in the properties is due to the incorporation of natural reinforcing fibers, coconut dust along with the other components in the composition of the present disclosure. Furthermore, from Table 3 it is evident that the test specimen 1 and test specimen 2 have higher flexural strength and flexural modulus which are desirable for automobile application. It is also observed that the impact strength and the tensile strength of the test specimen 1 is higher than the comparative example which are desirable for the automobile application.
From Figure 2 it is confirmed that the improved interfacial balance of composition of the present disclosure is improved due to the interfacial adhesion between polypropylene (PP), maleic anhydride-grafted polypropylene (MAPP), bamboo fiber and aluminium trihydrate (ATH) through the formation of an ester linkage at the interface.
TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of
a lignocellulosic composite based thermoplastic composition that;
utilizes natural reinforcing fiber to reduce melt flow index;
is used in automobile applications;
is cost-effective; and
is eco-friendly,
and
a process for the preparation of a lignocellulosic composite based thermoplastic composition that;
is simple, and
economic and effective
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising, will be understood to imply the inclusion of a stated element, integer or step,” or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:

1. A lignocellulosic composite based thermoplastic composition comprising:
i) a thermoplastic polymer;
ii) natural reinforcing fibers;
iii) a coupling agent;
iv) an impact modifier;
v) a flame retardant; and
vi) metal stearates; and
vii) optionally, coconut dust.

2. The composition as claimed in claim 1, wherein
i) said thermoplastic polymer is present in an amount in the range of 50 mass % to 65 mass %;
ii) said natural reinforcing fibers are present in an amount in the range of 15 mass % to 25 mass %;
iii) said coupling agent is present in an amount in the range of 2 mass % to 10 mass %;
iv) said impact modifier is present in an amount in the range of 5 mass % to 15 mass %;
v) said flame retardant is present in an amount in the range of 2 mass % to 10 mass %;
vi) said metal stearates are present in an amount in the range of 0.5 mass% to 2 mass%; and
vii) said coconut dust is present in an amount in the range of 0 mass % to 2.5 mass %;
wherein said mass% of each ingredient is with respect to the total amount of said composition.
3. The composition as claimed in claim 1, wherein
a) said thermoplastic polymer is at least one selected from polypropylene (PP), and polyethylene (PE);
b) said natural reinforcing fibers are at least one selected from the group consisting of bamboo fibers, sisal fibers, flax fibers, hemp fibers and wood fibers;
c) said coupling agent is at least one selected from the group consisting of maleic anhydride-grafted polypropylene (MAPP), and organo-silanes;
d) said impact modifier is at least one selected from the group consisting of ethylene propylene diene monomer (EPDM) rubber, vinyl rubber and thermoplastic elastomer;
e) said flame retardant is at least one selected from the group consisting of phenol, phosphates and aluminium trihydrate (ATH); and
f) said metal stearates is at least two selected from the group consisting of calcium stearate, zinc stearate; magnesium stearate and aluminium stearate; and
g) said coconut dust is at least one selected from the group consisting of, coir fiber powder, and coco peat;
wherein a mass ratio of said at least two metal stearates is in the range of 3:1 to 1:3.
4. The composition as claimed in claim 1, is characterized by having:
a. density in the range of 0.95 g/cc to 1 g/cc, when measured as per ASTM D792 standard;
b. MFI in the range of 9 g/10 min to 11 g/10 min, when measured as per ASTM D1238 standard;
c. melting point in the range of 160 °C to 170 °C, when measured as per ASTM D3418 standard;
d. crystallization point in the range of 115 °C to 125 °C, when measured as per ASTM D3418 standard; and
e. degradation temperature in the range of 450 °C to 470 °C, when measured as per ASTM E1131 standard.
5. A process for preparation of a thermoplastic composition, said process comprising the following steps:
i) treating predetermined amounts of natural reinforcing fibers with alkali solution at a first predetermined temperature for a first predetermined time period to obtain treated fibers;
ii) washing said treated fibers with water followed by cutting to obtain fibers having predetermined size;
iii) optionally, separately obtaining a predetermined amount of coconut dust and mixing with said fibers followed by drying at a second predetermined temperature for a time period in the range of 30 minutes to 45 minutes to obtain a resultant mixture; and
iv) adding predetermined amounts of at least one thermoplastic polymer, at least one coupling agent, at least one impact modifier, at least one flame retardant and at least two metal stearates in said resultant mixture or said fibers followed by mixing in a extruder at a third predetermined temperature at a predetermined torque and at a predetermined speed to obtain said lignocellulosic composite based thermoplastic composition.
6. The process as claimed in claim 5, wherein
i) said thermoplastic polymer is present in an amount in the range of 50 mass % to 65 mass %;
ii) said natural reinforcing fibers are present in an amount in the range of 15 mass % to 25 mass %;
iii) said coconut dust is present in an amount in the range of 0 mass % to 2.5 mass %;
iv) said coupling agent is present in an amount in the range of 2 mass % to 10 mass %;
v) said impact modifier is present in an amount in the range of 5 mass % to 15 mass %;
vi) said flame retardant is present in an amount in the range of 2 mass % to 10 mass %; and
vii) said metal stearates are present in an amount in the range of 0.5 mass% to 2 mass%;
wherein said mass% of each ingredient is with respect to the total amount of said composition.
7. The process as claimed in claim 5, wherein
a) said thermoplastic polymer is at least one selected from the group consisting of polypropylene (PP), and polyethylene (PE);
b) said natural reinforcing fibers is at least one selected from the group consisting of bamboo fibers, sisal fibers, flax fibers, hemp fibers and wood fibers;
c) said coconut dust is at least one selected from the group consisting of coir fiber powder and coco peat;
d) said coupling agent is at least one selected from the group consisting of maleic anhydride-grafted polypropylene (MAPP) and organo-silanes;
e) said impact modifier is at least one selected from the group consisting of ethylene propylene diene monomer (EPDM) rubber, vinyl rubber and thermoplastic elastomer;
f) said flame retardant is at least one selected from the group consisting of phenol, phosphates and aluminium trihydrate (ATH); and
g) said metal stearates is at least two selected from the group consisting of calcium stearate, zinc stearate, magnesium stearate and aluminium stearate.
8. The process as claimed in claim 5, wherein said alkali solution is at least one selected from caustic soda solution (NaOH), potassium hydroxide (KOH) solution, and calcium hydroxide (Ca(OH)2); and wherein said alkali solution have a concentration in the range of 0.3 N to 0.8 N.
9. The process as claimed in claim 5, wherein said predetermined size is in the range of 0.5 mm to 2 mm.
10. The process as claimed in claim 5, wherein
i) said first predetermined temperature is in the range of 25 °C to 35 °C;
ii) said second predetermined temperature is in the range of 40 °C to 80 °C; and
iii) said third predetermined temperature is in the range of 170 °C to 210 °C.
11. The process as claimed in claim 5, wherein
a) said first predetermined time period is in the range of 20 minutes to 40 minutes;
b) said predetermined torque is in the range of 60 Nm to 80 Nm; and
c) said predetermined speed is in the range of 160 rpm to 200 rpm.
12. An article made by using the composition as claimed in claim 1, is characterized by having:
a) tensile strength in the range of 20 MPa to 40 MPa; when measured as per ASTM D 638 standard;
b) tensile modulus in the range of 1760 MPa to 1840 MPa; when measured as per ASTM D 638 standard;
c) flexural strength in the range of 20 MPa to 60 MPa, when measured as per ASTM D790 standard;
d) flexural modulus in the range of 2200 MPa to 2400 MPa, when measured as per ASTM D790 standard;
e) notched impact strength at 23 °C in the range of 50 J/m to 65 J/m, when measured as per ASTM S256; and
f) heat deflection temperature at 0.45 MPa, in the range of 120 °C to 150 °C, when measured as per ASTM D 648 standard;
g) mold shrinkage in the range of 2% to 3%, when measured as per ASTM D 955.
Dated this 1st Day of September, 2023

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K. DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT CHENNAI