DESC:FIELD
The present disclosure relates to an unfilled polypropylene 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.
Unfilled polypropylene: The term “unfilled polypropylene” refers to a subcategory of polypropylene that exhibits isotropic linear shrinkage behavior .i.e. the shrinkage occurs equally in all directions.
High impact polypropylene copolymer: The term “high impact polypropylene copolymer” refers to a polymer that has high degree of toughness and that helps to achieve the desired impact strength at room temperature and at low temperatures (-30 °C).
High crystalline polypropylene copolymer: The term “high crystalline polypropylene copolymer” refers to a polymer that has high degree of crystallinity (35 % to 50%), high stiffness and ordered orientation that helps to achieve higher intermolecular bonding, high strength and controlled warpage.
Melt flow index (MFI): The term “Melt flow index (MFI)” refers to a measurement of the ease of flow of the melt of a thermoplastic polymer. MFI is calculated as the weight of the polymer in grams flowing in 10 minutes through a die of specific diameter and length by a pressure applied by the given weight at the given temperature.
Warpage: The term “Warpage” refers to a result of being bent or twisted out of shape, typically as a result of the effects of heat or damp.
Haptic: The term “Haptic” refers to a sense of touch. (It is derived from the Greek word for touch). It is related to the use of the tactile sensations in interfaces.
Thermal aging: The term “thermal aging” refers to a test which is used to measure the ability of the product to withstand at the elevated temperatures for an extended period of time.
Spiral flow: The term “spiral flow” refers to a test which is used to measure the distance of a mold compound that will flow when exposed to mold temperature and pressure. As well as the spiral flow is used to compare the different materials and to control the molding compound quality.
Hindered Phenol: The term “hindered phenol” refers to the phenols with one or more bulky functional groups such as tertiary butyl. Hindered phenol is the free radical scavengers which combine with the peroxy and the alkoxy radicals to break any autocatalytic cycle.
Hindered Phosphites: The term “hindered phosphites” refers to the phosphites that act as a chain-breaking primary antioxidants when substituted by an alkoxyl radicals. The hindered alkoxyl radicals are then released that terminates the radical-chain oxidation.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Polypropylene has many excellent properties such as moldability, recycling efficiency, enhanced physical properties and the like. Due to these properties polypropylene is widely used in variety of applications such as automobile, electronics, packaging, and the like. Particularly, in automobile industry, the polypropylene is used in variety of parts which includes bumper facials, instrumental panels, cable insulation, door trims and the like.
The conventional polypropylene used in the automobile industry comprises higher percentage of fillers. However, the incorporation of higher percentage of fillers in the polypropylene adversely affects the quality as well as the performance of the product. Moreover, the higher percentage of the fillers in the polypropylene leads to an increase in the weight of the products.
Therefore, there is felt a need to provide an unfilled polypropylene composition and a process for its preparation that obviates the drawbacks mentioned hereinabove or at least provide a useful 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.
Another object of the present disclosure is to provide an unfilled polypropylene composition.
Yet another object of the present disclosure is to provide an unfilled polypropylene composition that can be used in automobile industry.
Still another object of the present disclosure is to provide an unfilled polypropylene composition that can be used for light weight interior trims.
Another object of the present disclosure is to provide an unfilled polypropylene composition that helps in weight reduction and cost reduction of the automobile products.
Yet another object of the present disclosure is to provide an unfilled polypropylene composition which can provide balanced mechanical and thermal properties to achieve structural durability, thermal ageing and impact resistance at low temperature.
Still another object of the present disclosure is to provide a simple and environment friendly process for the preparation of an unfilled polypropylene 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 an unfilled polypropylene composition. The composition comprises a high crystalline polypropylene copolymer; a high impact polypropylene copolymer; at least one polyolefin elastomer; and at least one additive.
In an embodiment of the present disclosure, the composition comprises 15 mass% to 30 mass% of the high crystalline polypropylene copolymer; 55 mass% to 70 mass% of the high impact polypropylene copolymer and 5 mass% to 15 mass% of the polyolefin elastomer, and 3 mass% to 7 mass% of the additive. The mass% of each ingredient is with respect to the total mass of the unfilled polypropylene composition.
In an embodiment of the present disclosure, the high crystalline polypropylene copolymer is a reaction product of a polypropylene homopolymer and a polyethylene polymer.
In an embodiment of the present disclosure, the high crystalline polypropylene copolymer is obtained by polymerizing predetermined amounts of the polypropylene homopolymer and the polyethylene polymer at a temperature in the range of 170 °C to 250 °C and at a pressure in the range of 10 bar to 30 bar under stirring at a speed in the range of 500 rpm to 700 rpm. The polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization.
In an embodiment of the present disclosure, the high impact polypropylene copolymer is a reaction product of a block polypropylene copolymer and a diene monomer.
In an embodiment of the present disclosure, the high impact polypropylene copolymer is obtained by polymerizing predetermined amounts of the block polypropylene copolymer and the diene monomer at a temperature in the range of 170 °C to 250 °C and at a pressure in the range of 10 bar to 30 bar under stirring at a speed in the range of 500 rpm to 700 rpm. The polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization.
The present disclosure further relates to a process for the preparation of the unfilled polypropylene composition. The process comprises the steps of polymerizing predetermined amounts of a polypropylene homopolymer and a polyethylene polymer at a first predetermined temperature and at a first predetermined pressure under stirring at a first predetermined speed to obtain a high crystalline polypropylene copolymer. The polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization. Separately, predetermined amounts of a block polypropylene copolymer and a diene monomer are polymerized at a second predetermined temperature and at a second predetermined pressure under stirring at a second predetermined speed to obtain a high impact polypropylene copolymer. The polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization. Predetermined amounts of the high crystalline polypropylene copolymer, the high impact polypropylene copolymer, a polyolefin elastomer and at least one additive are compounded at a speed in the range of 800 rpm to 1200 rpm and at a third predetermined temperature to obtain the unfilled polypropylene composition. The compounding is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to compounding.
In an embodiment of the present disclosure, the polyethylene polymer is at least one selected from polyethylene butene and polyethylene octene.
In an embodiment of the present disclosure, the mass ratio of the polypropylene homopolymer to the polyethylene polymer is in the range of 1:0.05 to 1:0.15.
In an embodiment of the present disclosure, the diene monomer is at least one selected from the group consisting of ethylene, butene, isobutene, pentene, hexene, polyethylene octene, decene, acyclic monomers, 2-methyl-1-pentene, 2,3-dimethyl-1-pentene, 4-methyl-1-pentene, 2-methyl-1-butene, cyclopentene, cyclobutene, cyclobutadiene, dicyclopentadiene and hexadiene.
In an embodiment of the present disclosure, the mass ratio of the block polypropylene copolymer to the diene monomer is in the range of 1:0.3 to 1:0.7.
In an embodiment of the present disclosure, the polyolefin elastomer is selected from the group consisting of ethylene butene and ethylene octene.
In an embodiment of the present disclosure, the additive is at least one selected from the group consisting of an antioxidant, an UV stabilizer, a scratch resistant additive and processing aids.
In an embodiment of the present disclosure, the antioxidant is selected from the group consisting of hindered phenols and hindered phosphites.
In an embodiment of the present disclosure, the UV stabilizer is selected from the group consisting of hindered amine light stabilizer, UV benzotriazoles and UV benzoates.
In an embodiment of the present disclosure, the scratch resistant additive and the processing aid are independently selected from siloxane based wax, calcium stearate, and magnesium stearate.
In an embodiment of the present disclosure, the composition is characterized by a spiral flow as per ASTM D3123 in the range of 56 mm to 59 mm; a degree of crystallinity as per ASTM D3418 as in the range of 35% to 60%; and a density as per ASTM D792 in the range of 0.88 g/cc to 0.92 g/cc.
In an embodiment of the present disclosure, the first predetermined temperature is in the range of 170 °C to 250 °C; the first predetermined speed is in the range of 500 rpm to 700 rpm; and the first predetermined pressure is in the range of 10 bar to 30 bar.
In an embodiment of the present disclosure, the second predetermined temperature is in the range of 170 °C to 250 °C; second predetermined speed is in the range of 500 rpm to 700 rpm; and the second predetermined pressure is in the range of 10 bar to 30 bar.
In an embodiment of the present disclosure, the third predetermined temperature is in the range of 170 °C to 250 °C.
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 the comparison of the densities of the unfilled polypropylene composition prepared in accordance with the present disclosure (example1) and comparative examples 1 and 2;
Figure 2: illustrates the comparison of the melt flow index (MFI) of the unfilled polypropylene composition prepared in accordance with the present disclosure (example1) and comparative examples 1 and 2;
Figure 3: illustrates the comparison of the tensile strengths of the unfilled polypropylene composition prepared in accordance with the present disclosure (example1) and comparative examples 1 and 2;
Figure 4: illustrates the comparison of the flexural strengths of the unfilled polypropylene composition prepared in accordance with the present disclosure (example1) and comparative examples 1 and 2; and

Figure 5: illustrates the comparison of heat deflection temperature (HDT) of the unfilled polypropylene composition prepared in accordance with the present disclosure (example1) and comparative examples 1 and 2.
DETAILED DESCRIPTION
The present disclosure relates to an unfilled polypropylene 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.
Polypropylene and various polypropylene compositions are widely used in the automobile industry. The conventional polypropylene compositions used in the automobile industry comprises higher percentage of fillers. However, the incorporation of higher percentage of fillers in the polypropylene compositions adversely affects the quality as well as the performance of the product. Moreover, the higher percentage of the fillers in the polypropylene composition leads to the increase in the weight of the products.
The present disclosure provides an unfilled polypropylene composition and a process for its preparation.
In an aspect, the present disclosure provides an unfilled polypropylene composition. The composition comprises a high crystalline polypropylene copolymer; a high impact polypropylene copolymer; at least one polyolefin elastomer; and at least one additive.
In an embodiment of the present disclosure, the unfilled polypropylene composition comprises:
(i) 15 mass% to 30 mass% of the high crystalline polypropylene copolymer;
(ii) 55 mass % to 70 mass% of the high impact polypropylene copolymer;
(iii) 5 mass % to 15 mass % of the polyolefin elastomer, and
(iv) 3 mass% to 7 mass% of the additive.
wherein the mass% of each ingredient is with respect to the total mass of the unfilled polypropylene composition.
In a first exemplary embodiment of the present disclosure, the unfilled polypropylene composition comprises;
(i) 25 mass% of the high crystalline polypropylene copolymer;
(ii) 60 mass% of the high impact polypropylene copolymer;
(iii) 10 mass% of the polyolefin elastomer; and
(iv) 5 mass % of the additive,
wherein the mass% of each ingredient is with respect to the total mass of the unfilled polypropylene composition.
In a second exemplary embodiment of the present disclosure, the unfilled polypropylene composition comprises;
(i) 20 mass% of the high crystalline polypropylene copolymer;
(ii) 65 mass% of the high impact polypropylene copolymer;
(iii) 10 mass% of the polyolefin elastomer, and
(iv) 5 mass % of the additive,
wherein the mass% of each ingredient is with respect to the total mass of the unfilled polypropylene composition.
In a third exemplary embodiment of the present disclosure, the unfilled polypropylene composition comprises;
(i) 15 mass% of the high crystalline polypropylene copolymer;
(ii) 70 mass% of the high impact polypropylene copolymer;
(iii) 10 mass% of the polyolefin elastomer, and
(iv) 5 mass % of the additive,
wherein the mass% of each ingredient is with respect to the total mass of the unfilled polypropylene composition.
In an embodiment of the present disclosure, the high crystalline polypropylene copolymer is a reaction product of a polypropylene homopolymer and a polyethylene polymer.
In an embodiment of the present disclosure, the high crystalline polypropylene copolymer is obtained by polymerizing predetermined amounts of the polypropylene homopolymer and the polyethylene polymer at a temperature in the range of 170 °C to 250 °C and at a pressure in the range of 10 bar to 30 bar under stirring at a speed in the range of 500 rpm to 700 rpm. The polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization.
In an exemplary embodiment of the present disclosure, the high crystalline polypropylene copolymer is obtained by polymerizing predetermined amounts of the polypropylene homopolymer and the polyethylene polymer at 210 °C and at 25 bar under stirring at 600 rpm. The polymerization is performed for 0.06 minutes/kg of the ingredients subjected to polymerization
In an embodiment of the present disclosure, the polyethylene polymer is at least selected from polyethylene butene and polyethylene octene.
In an exemplary embodiment of the present disclosure, the high crystalline polypropylene copolymer is a reaction product of polypropylene homopolymer and polyethylene octene.
In another exemplary embodiment of the present disclosure, the high crystalline polypropylene copolymer is a reaction product of polypropylene homopolymer and polyethylene butene.
In an embodiment of the present disclosure, a mass ratio of the polypropylene homopolymer to the polyethylene polymer is in the range of 1:0.05 to 1:0.15. In an exemplary embodiment of the present disclosure, a mass ratio of the polypropylene homopolymer to the polyethylene polymer is 1:0.11.
In an embodiment of the present disclosure, the high impact polypropylene copolymer is a reaction product of a block polypropylene copolymer and a diene monomer.
In an embodiment of the present disclosure, the high impact polypropylene copolymer is obtained by polymerizing predetermined amounts of the block polypropylene copolymer and the diene monomer at a temperature in the range of 170 °C to 250 °C and at a pressure in the range of 10 bar to 30 bar under stirring at a speed in the range of 500 rpm to 700 rpm.
In an embodiment of the present disclosure, the polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization.
In an exemplary embodiment of the present disclosure, the high impact polypropylene copolymer is obtained by polymerizing predetermined amounts of the block polypropylene copolymer and the diene monomer at 210 °C and at 25 bar under stirring at 600 rpm. The polymerization is performed for 0.06 minutes/kg of the ingredients subjected to polymerization.
In an embodiment of the present disclosure, the diene monomer is at least one selected from the group consisting of ethylene, butene, isobutene, pentene, hexene, polyethylene octene, decene, acyclic monomers, 2-methyl-1-pentene, 2,3-dimethyl-1-pentene, 4-methyl-1-pentene, 2-methyl-1-butene, cyclopentene, cyclobutene, cyclobutadiene. In an exemplary embodiment of the present disclosure, the diene monomer is polyethylene octene.
In an exemplary embodiment of the present disclosure, the high impact polypropylene copolymer is a reaction product of block polypropylene copolymer and polyethylene octene.
In an embodiment of the present disclosure, a mass ratio of the block polypropylene copolymer to the diene monomer is in the range of 1:0.3 to 1:0.7. In an embodiment of the present disclosure, the mass ratio of the block polypropylene copolymer to the diene monomer is 1: 0.43.
In an embodiment of the present disclosure, the high crystalline polypropylene copolymer is a reactor based high crystalline polypropylene copolymer and the high impact polypropylene copolymer is a reactor based high impact polypropylene copolymer.
The high crystalline polypropylene copolymer has high degree of crystallinity which helps to achieve higher intermolecular bonding, higher strength and controlled warpage
The reactor based high crystallinity polypropylene copolymer and the reactor based high impact polypropylene copolymer materials are independently made in the polymerization reactor itself.
The high impact polypropylene copolymer has excellent impact resistance at low temperature and improved toughness. The high impact polypropylene copolymer has high degree of toughness that helps to achieve desired impact strength at room temperature and at -30 °C.
The balanced combinations of the reactor based high crystallinity polypropylene copolymer, the reactor based high impact polypropylene copolymer and the polyolefin elastomers provides the balanced mechanical and thermal properties in terms of tensile strength, flexural modulus, flexural strength, impact strength and heat distortion temperature properties to the unfilled polypropylene composition that help to achieve structural durability, thermal ageing and cold impact criteria.
In an embodiment of the present disclosure, the polyolefin elastomer is selected from the group consisting of ethylene butene and ethylene octene. In an exemplary embodiment of the present disclosure, the polyolefin elastomer is ethylene butene. In another exemplary embodiment of the present disclosure, the polyolefin elastomer is ethylene octene.
In an embodiment of the present disclosure, the additive is at least one selected from the group consisting of an antioxidant, an UV stabilizer, a scratch resistant additive and processing aids.
In an embodiment of the present disclosure, the antioxidant is selected from primary antioxidants and secondary antioxidants. In an embodiment of the present disclosure, the primary antioxidants and secondary antioxidants are independently selected from the group consisting of hindered phenols and hindered phosphites. In an exemplary embodiment of the present disclosure, the antioxidant is a mixture of hindered phenols and hindered phosphites.
In an embodiment of the present disclosure, the UV stabilizer is selected from hindered amine light stabilizer, UV benzotriazoles and UV benzoates. In an exemplary embodiment of the present disclosure, the UV stabilizer is a mixture of hindered amine light stabilizer, UV benzotriazoles and UV benzoates.
In an embodiment of the present disclosure, the scratch resistant additive and the processing aid are independently selected from the group consisting of siloxane based wax and calcium stearate, magnesium stearate. In an exemplary embodiment of the present disclosure, the scratch resistant additive is siloxane based wax. In an exemplary embodiment of the present disclosure, the processing aid is magnesium stearate.
In an embodiment of the present disclosure, the unfilled polypropylene composition is characterized by having a spiral flow as per ASTM D3123 in the range of 56 to 59 mm; a degree of crystallinity as per ASTM D3418 in the range of 35% to 60%; and a density as per ASTM D792 in the range of 0.88 g/cc to 0.92 g/cc. In an exemplary embodiment of the present disclosure, the unfilled polypropylene composition is characterized by having a spiral flow as per ASTM D3123 of 58 mm; a degree of crystallinity as per ASTM D3418 of 40 % and a density as per ASTM D792 of 0.9 g/cc.
Higher spiral flow helps to achieve light weight thin wall design (2.5mm) applications with excellent haptics. Higher degree of crystallinity helps to achieve higher intermolecular bonding, higher strength and controlled warpage. Lower density helps to achieve significant weight reduction (~15%).
In another aspect, the present disclosure provides a process for the preparation of an unfilled polypropylene composition. The process comprises the following steps:
i) polymerizing predetermined amounts of a polypropylene homopolymer and a polyethylene polymer at a first predetermined temperature and at a first predetermined pressure under stirring at a first predetermined speed to obtain a high crystalline polypropylene copolymer,
wherein the polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization;
ii) separately, polymerizing predetermined amounts of a block polypropylene copolymer and a diene monomer at a second predetermined temperature and at a second predetermined pressure under stirring at a second predetermined speed to obtain a high impact polypropylene copolymer,
wherein the polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization; and
iii) compounding predetermined amounts of the high crystalline polypropylene copolymer obtained in step (i), the high impact polypropylene copolymer obtained in step (ii), a polyolefin elastomer and at least one additive at a speed in the range of 800 rpm to 1200 rpm at a third predetermined temperature to obtain the unfilled polypropylene composition,
wherein the compounding is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to compounding.
The process is described in detail herein below.
In a first step, a predetermined amounts of a polypropylene homopolymer and a polyethylene polymer is polymerized at a first predetermined temperature and at a first predetermined pressure under stirring at a first predetermined speed to obtain a high crystalline polypropylene copolymer. The polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization.
The high crystalline polypropylene copolymer has higher degree of crystallinity, higher stiffness and ordered molecular orientation which improves warpage aspect.
In an embodiment of the present disclosure, the polyethylene polymer is at least one selected from polyethylene butene and polyethylene octene. In an exemplary embodiment of the present disclosure, the polyethylene polymer is polyethylene octene.
In an embodiment of the present disclosure, the predetermined amount of the polypropylene homopolymer is in the range of 85 mass% to 95 mass% with respect to the total mass of the high crystalline polypropylene copolymer. In an exemplary embodiment of the present disclosure, the predetermined amount of the polypropylene homopolymer is 90 mass% with respect to the total mass of the high crystalline polypropylene copolymer.
In an embodiment of the present disclosure, the predetermined amount of the polyethylene polymer is in the range of 5 mass% to 15 mass% with respect to the total mass of the high crystalline polypropylene copolymer. In an exemplary embodiment of the present disclosure, the predetermined amount of the polyethylene polymer is 10 mass% with respect to the total mass of the high crystalline polypropylene copolymer.
In an embodiment of the present disclosure, the first predetermined temperature is in the range of 170 °C to 250 °C. In an exemplary embodiment of the present disclosure, the first predetermined temperature is 210 °C.
In an embodiment of the present disclosure, the first predetermined speed is in the range of 500 rpm to 700 rpm. In an exemplary embodiment of the present disclosure, the first predetermined speed is 600 rpm.
In an exemplary embodiment of the present disclosure, the polymerization is performed for 0.06 minutes/kg of the ingredients subjected to polymerization.
In an embodiment of the present disclosure, the first predetermined pressure is in the range of 10 bar to 30 bar. In an exemplary embodiment of the present disclosure, the first predetermined pressure is 25 bar.
In a second step, separately, predetermined amounts of a block polypropylene copolymer and a diene monomer are polymerized at a second predetermined temperature and at a second predetermined pressure under stirring at a second predetermined speed to obtain a high impact polypropylene copolymer. The polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization.
The high impact polypropylene copolymer has excellent impact resistance at low temperature and improved toughness. The high impact polypropylene copolymer has high degree of toughness that helps to achieve desired impact strength at room temperature and at -30 °C.
In an embodiment of the present disclosure, the diene polymer is at least one selected from the group consisting of ethylene, butene, isobutene, pentene, hexene, polyethylene octene, decene, acyclic monomers, 2-methyl-1-pentene, 2,3-dimethyl-1-pentene, 4-methyl-1-pentene, 2-methyl-1-butene, cyclopentene, cyclobutene, cyclobutadiene, dicyclopentadiene and hexadiene. In an exemplary embodiment of the present disclosure, the diene polymer is polyethylene octene.
In an embodiment of the present disclosure, the predetermined amount of the block polypropylene copolymer is in the range of 60 mass% to 80 mass% with respect to the total mass of the high impact polypropylene copolymer. In an embodiment of the present disclosure, the predetermined amount of the block polypropylene copolymer is 70 mass% with respect to the total mass of the high impact polypropylene copolymer.
In an embodiment of the present disclosure, the predetermined amount of the diene polymer is in the range of 20 mass% to 40 mass% with respect to the total mass of the high impact polypropylene copolymer. In an exemplary embodiment of the present disclosure, the predetermined amount of the diene polymer is 30 mass% with respect to the total mass of the high impact polypropylene copolymer.
In an embodiment of the present disclosure, the second predetermined temperature is in the range of 170 °C to 250 °C. In an exemplary embodiment of the present disclosure, the second predetermined temperature is 210 °C.
In an embodiment of the present disclosure, the second predetermined speed is in the range of 500 rpm to 700 rpm. In an exemplary embodiment of the present disclosure, the second predetermined speed is 600 rpm.
In an exemplary embodiment of the present disclosure, the time period is 0.06 minutes/kg of the ingredients subjected to polymerization.
In an embodiment of the present disclosure, the second predetermined pressure is 10 bar to 30 bar. In an exemplary embodiment of the present disclosure the second predetermined pressure is 25 bar.
In an exemplary embodiment of the present disclosure, the polymerization is performed for 0.06 minutes/kg of the ingredients subjected to polymerization.
In a third step, a predetermined amounts of the high crystalline polypropylene copolymer obtained in step (i), the high impact polypropylene copolymer obtained in step (ii), a polyolefin elastomer and at least one additive are compounded at a speed in the range of 800 rpm to 1200 rpm to obtain the unfilled polypropylene composition. The compounding is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to compounding.
In an exemplary embodiment, the speed is 1000 rpm.
In an embodiment of the present disclosure, the compounding is performed in an extruder. In an exemplary embodiment of the present disclosure, the extruder is a twin screw extruder.
In an embodiment of the present disclosure, the torque is maintained in the range of 50% to 80% of full capacity of twin screw extruder by maintaining the speed of the screw in the rage of 800 rpm to 1200 rpm.
In an embodiment of the present disclosure, the predetermined amount of the high crystalline polypropylene copolymer is in the range of 15 mass% to 30 mass % with respect to the total mass of the unfilled polypropylene composition. In an exemplary embodiment of the present disclosure, the predetermined amount of the high crystalline polypropylene copolymer is 25 mass% with respect to the total mass of the unfilled polypropylene composition. In another exemplary embodiment of the present disclosure, the predetermined amount of the high crystalline polypropylene copolymer is 20 mass% with respect to the total mass of the unfilled polypropylene composition. In still another exemplary embodiment of the present disclosure, the predetermined amount of the high crystalline polypropylene copolymer is 15 mass% with respect to the total mass of the unfilled polypropylene composition.
In an embodiment of the present disclosure, the predetermined amount of high impact polypropylene copolymer is in the range of 55 mass % to 70 mass % with respect to the total mass of the unfilled polypropylene composition. In an exemplary embodiment of the present disclosure, the predetermined amount of high impact polypropylene copolymer is 60 mass % with respect to the total mass of the unfilled polypropylene composition. In another exemplary embodiment of the present disclosure, the predetermined amount of high impact polypropylene copolymer is 65 mass % with respect to the total mass of the unfilled polypropylene composition. In still another exemplary embodiment of the present disclosure, the predetermined amount of high impact polypropylene copolymer is 70 mass % with respect to the total mass of the unfilled polypropylene composition.
In an embodiment of the present disclosure, the predetermined amount of polyolefin elastomer is in the range of 5 mass% to 15 mass% with respect to the total mass of the unfilled polypropylene composition. In an exemplary embodiment of the present disclosure, the predetermined amount of polyolefin elastomer is 10 mass% with respect to the total mass of the unfilled polypropylene composition.
In an embodiment of the present disclosure, the predetermined amount of additive is in the range of 3 mass% to 7 mass % with respect to the total mass of said unfilled polypropylene composition. In an exemplary embodiment of the present disclosure, the predetermined amount of additive is 5 mass % with respect to the total mass of said unfilled polypropylene composition.
In an embodiment of the present disclosure, the third predetermined temperature is in the range of 170 °C to 250 °C. In an exemplary embodiment of the present disclosure, the third predetermined temperature is 210 °C.
In an exemplary embodiment of the present disclosure, the compounding is performed for 0.06 minutes/kg of the ingredients subjected to compounding.
The unfilled polypropylene composition of the present disclosure provides performance targets such as the unfilled polypropylene composition of the present disclosure is light weight (density of 0.90 g/cc), cost effective and can be commercially scaled up. Moreover, the unfilled polypropylene composition of the present disclosure helps to reduce weight by 15% and cost by 12% per vehicle.
The unfilled polypropylene composition of the present disclosure has higher spiral flow which helps to achieve the light weight thin wall design (2.5mm) applications with excellent haptic. In addition, the unfilled polypropylene composition of the present disclosure has higher degree of crystallinity which helps to achieve higher intermolecular bonding, higher strength and controlled warpage. Further, the unfilled polypropylene composition of the present disclosure provides balanced mechanical and thermal properties that help to achieve structural durability, thermal aging and cold impact criteria.
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
Example 1: Preparation of the unfilled polypropylene composition in accordance with the present disclosure.
(i) Preparation of the high crystalline polypropylene copolymer.
90% of polypropylene homopolymer and 10% of polyethylene octene (polyethylene polymer) were polymerized in a reactor at 210 °C (first predetermined temperature) and at 25 bar (first predetermined pressure) under stirring at 600 rpm (first predetermined speed) for 0.06 minutes/kg of the ingredients subjected to polymerization to obtain the high crystalline polypropylene copolymer.
(ii) Preparation of the high impact polypropylene copolymer.
Separately, 70 mass% of block polypropylene copolymer and 30% of polyethylene octene (diene monomer) were polymerized in a reactor at 210 °C (second predetermined temperature) and at 25 bar pressure (second predetermined pressure) under stirring at 600 rpm (second predetermined speed) for 0.06 minutes/kg of the ingredients subjected to polymerization to obtain the high impact polypropylene copolymer.
(iii) Preparation of the unfilled polypropylene composition.
25% of high crystalline polypropylene copolymer obtained in step (i), 60% of high impact polypropylene copolymer obtained in step (ii), 10% of ethylene octene (polyolefin elastomer) and 5% of additives were compounded in a twin extruder at a speed of 1000 rpm (third predetermined speed) at 210 °C (third predetermined temperature) for 0.06 minutes/kg of the ingredients subjected to compounding to obtain the unfilled polypropylene composition.
Example 2 and example 3 were prepared by following the same process steps as examples 1 except the amount of the ingredients were changed.
Table 1: illustrates the different composition of the unfilled polypropylene composition prepared in accordance with the present disclosure.

Sr.
No Ingredients Example 1 Example 2 Example 3 Example 4 Example 5 Example 6
1. Reactor based High Crystalline Polypropylene copolymer 25 wt% 20 wt% 25 wt% 15 wt% 15 wt% 20 wt%
2. Reactor based High Impact Polypropylene copolymer 60 wt% 65 wt% 60 wt% 70 wt% 70 wt% 65 wt%
3. Polyolefin elastomer Polyethylene butene 10 wt% --- --- --- 10 wt% 10 wt%
Polyethylene octene --- 10 wt% 10 wt% 10 wt% --- ---
4. Additives Antioxidant - Hindered phenols and hindered phosphites 5 wt% 5 wt% 5 wt% 5 wt% 5 wt% 5 wt%
UV stabilizer - Hindered amine light stabilizer, UV benzotriazoles and UV benzoates
Scratch resistance additive - siloxane based wax
Processing aid – Magnesium stearate
Comparative examples:
The comparative examples 1 and 2 were purchased commercially. In the comparative examples 1 and 2, the high crystalline polypropylene copolymer and the high impact polypropylene copolymer are not the reactor based copolymers.
Table 2: illustrates the different composition of the polypropylene composition of the comparative examples.
Sr.
No Ingredients Comparative Example 1 Comparative Example 2
1. High Crystalline Polypropylene copolymer 20 wt% 30 wt%
2. High Impact Polypropylene copolymer 50 wt% 55 wt%
3. Polyolefin elastomer Poly ethylene butene 5 wt% ---
Poly ethylene octene --- 10 wt%
4. Filler Talc 20 wt% ---
5. Additives Antioxidant - Hindered phenols 5 wt% 5 wt%
UV stabilizer - Hindered amine light stabilizer
Scratch resistance additive - siloxane based wax
Processing aid – calcium stearate
Characterization of the unfilled polypropylene composition in accordance with the present disclosure
The unfilled polypropylene composition obtained in example 1 in accordance with the present disclosure and the comparative example 1 and 2 were subjected for the characterization tests. The results are demonstrated in table 3.
Table 3: Characterization of the unfilled polypropylene composition.
Sr. No Properties Standard Units Results
(Example 1)
(In accordance with the present disclosure) Comparative example 1 Comparative example 2
1. Melt Flow Index
(MFI) ASTMD1238 g/10min 35 20 15
2. Density ASTM D792 g /cc 0.90 1.07 0.92
3. Tensile strength ASTM D638 MPa 30 16 22
4. Flexural modulus ASTM D790 MPa 1350 1400 1000
5. Flexural strength ASTM D790 MPa 33 22 26
6. Notched Izod impact strength @ 23 °C ASTM D256 kg cm/cm 12 40 8
7. Notched Izod impact strength @ -30 °C 5 5 5
8. Heat Distortion
Temperature (HDT) ASTM D648 ° C 110 96 90
From table 3, it is observed that the Example 1 of the present disclosure has excellent balance in properties such as tensile strength (30 Mpa), flexural strength (33 Mpa), flexural modulus (1350 Mpa), impact strength (12 kgcm/cm), heat distortion temperature (110° C), melt flow index (35 g/10 mins) and density (0.9 g/cc). High tensile and flexural strength of the unfilled polypropylene composition of the present disclosure helps to meet the structural durability criteria in terms of load of 50N and deflection of = 2mm. High MFI and spiral flow of the unfilled polypropylene composition of the present disclosure helps to achieve light weight thin wall design of 2.5mm with excellent surface haptics. Lower density of the unfilled polypropylene composition of the present disclosure helps to achieve significant weight reduction (~15%) and high heat distortion temperature of the unfilled polypropylene composition of the present disclosure helps to meet thermal ageing criterias in terms of dimensional stability (=1mm).
Moreover, from table 3 it is observed that the flexural modulus of the composition given in comparative example 1 is high because of the incorporation talc as a filler. However the other properties such as tensile strength, flexural modulus, impact strength and MFI are not balanced and hence, not suitable for interior door/pillar trim applications. Further, the density of the composition of comparative example 1 is high which results in increased weight of the automobile products.
The impact strength of the composition given in comparative example 1 is high because of too much polypropylene copolymer (PPCP) impact modification which is not needed for interior door/pillar trim applications. Moreover, the other properties of the composition of comparative example 1 will get impacted for the automobile (interior door/pillar trim) applications.
From figure 1, it is evident that the density of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) is less than the density of the polypropylene composition of the comparative examples. The lesser density of the unfilled polypropylene composition of the present disclosure helps to achieve significant weight reduction of 15% in the automobile products .
From figure 2, it is evident that the MFI of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) is higher than the MFI of the polypropylene composition given in the comparative example 1 and comparative example 2.
Higher spiral flow defines that the material can sustain the shear rate and improve fillin. The higher MFI enables material to flow more however there is no consideration of shear rate. The higher MFI and spiral flow of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) helps to achieve light weight thin wall design (2.5 mm) applications with excellent surface haptics.
From figure 3, it is evident that the tensile strength of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) is higher than the tensile strength of the polypropylene composition given in the comparative example 1 and comparative example 2. The higher tensile strength of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) helps to meet the structural durability criteria in terms of load (50N) and deflection (=2mm).
From figure 4, it is evident that the flexural strength of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) is higher than the flexural strength of the polypropylene composition given in the comparative example 1 and comparative example 2. The higher flexural strength of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) helps to meet the structural durability criteria in terms of load (50N) and deflection (=2mm).
From figure 5, it is evident that the heat distortion temperature (HDT) of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) is higher than the HDT of the polypropylene composition given in the comparative example 1 and comparative example 2. The higher HDT of the unfilled polypropylene composition obtained in accordance with the present disclosure (example 1) helps to meet the thermal ageing criteria in terms of dimensional stability (=1mm).
TECHNICAL ADVANCES AND ECONOMIC SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of;
? an unfilled polypropylene composition which;
• is economical;
• provides higher spiral flow which can sustain shear rates at the thin wall profiles and complex contours during injection molding process. This aids to achieve light weight thin wall design (2.5mm) and complex reinforcement contours of the part design with excellent surface haptic;
• provides lower density to achieve significant weight reduction (~15%) of automobile products; and
• provides balanced mechanical and thermal properties to achieve structural durability, thermal aging and cold impact criteria of automobile products; and
? a process for preparing an unfilled polypropylene composition which;
• is simple, efficient and economical.
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 mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments 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. An unfilled polypropylene composition comprising:
(i) a high crystalline polypropylene copolymer;
(ii) a high impact polypropylene copolymer;
(iii) at least one polyolefin elastomer; and
(iv) at least one additive.
2. The composition as claimed in claim 1 comprises,
(i) 15 mass% to 30 mass% of said high crystalline polypropylene copolymer;
(ii) 55 mass% to 70 mass% of said high impact polypropylene copolymer;
(iii) 5 mass% to 15 mass% of said polyolefin elastomer; and
(iv) 3 mass% to 7 mass% of said additive.
wherein said mass% of each ingredient is with respect to the total mass of said unfilled polypropylene composition.
3. The composition as claimed in claim 1, wherein said high crystalline polypropylene copolymer is a reaction product of a polypropylene homopolymer and a polyethylene polymer.
4. The composition as claimed in claim 3, wherein said high crystalline polypropylene copolymer is obtained by polymerizing predetermined amounts of said polypropylene homopolymer and said polyethylene polymer at a temperature in the range of 170 °C to 250 °C and at a pressure in the range of 10 bar to 30 bar under stirring at a speed in the range of 500 rpm to 700 rpm; wherein said polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization.
5. The composition as claimed in claim 3, wherein said polyethylene polymer is at least one selected from polyethylene butene and polyethylene octene.
6. The composition as claimed in claim 3, wherein a mass ratio of said polypropylene homopolymer to said polyethylene polymer is in the range of 1:0.05 to 1:0.15.
7. The composition as claimed in claim 1, wherein said high impact polypropylene copolymer is a reaction product of a block polypropylene copolymer and a diene monomer.
8. The composition as claimed in claim 7, wherein said high impact polypropylene copolymer is obtained by polymerizing predetermined amounts of said block polypropylene copolymer and said diene monomer at a temperature in the range of 170 °C to 250 °C and at a pressure in the range of 10 bar to 30 bar under stirring at a speed in the range of 500 rpm to 700 rpm; wherein said polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of the ingredients subjected to polymerization.
9. The composition as claimed in claim 7, wherein said diene monomer is at least one selected from the group consisting of ethylene, butene, isobutene, pentene, hexene, polyethylene octene, decene, acyclic monomers, 2-methyl-1-pentene, 2,3-dimethyl-1-pentene, 4-methyl-1-pentene, 2-methyl-1-butene, cyclopentene, cyclobutene, cyclobutadiene, dicyclopentadiene and hexadiene.
10. The composition as claimed in claim 7, wherein a mass ratio of said block polypropylene copolymer to said diene monomer is in the range of 1:0.3 to 1:0.7.
11. The composition as claimed in claim 1, wherein said polyolefin elastomer is selected from the group consisting of ethylene butene and ethylene octene.
12. The composition as claimed in claim 1, wherein said additive is at least one selected from the group consisting of an antioxidant, an UV stabilizer, a scratch resistant additive and processing aids.
13. The composition as claimed in claim 12, wherein
i) said antioxidant is selected from the group consisting of hindered phenols and hindered phosphites;
ii) said UV stabilizer is selected from the group consisting of hindered amine light stabilizer, UV benzotriazoles and UV benzoates; and
iii) said scratch resistant additive and said processing aid are independently selected from siloxane based wax, calcium stearate, and magnesium stearate.
14. The composition as claimed in claim 1 is characterized by having:
i) a spiral flow as per ASTM D3123 is in the range of 56 mm to 59 mm;
ii) a degree of crystallinity as per ASTM D3418 is in the range of 35% to 60%; and
iii) a density as per ASTM D792 is in the range of 0.88 g/cc to 0.92 g/cc.
15. A process for the preparation of an unfilled polypropylene composition, said process comprising the following steps:
i) polymerizing predetermined amounts of a polypropylene homopolymer and a polyethylene polymer at a first predetermined temperature and at a first predetermined pressure under stirring at a first predetermined speed to obtain a high crystalline polypropylene copolymer,
wherein said polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of said ingredients subjected to polymerization;
ii) separately, polymerizing predetermined amounts of a block polypropylene copolymer and a diene monomer at a second predetermined temperature and at a second predetermined pressure under stirring at a second predetermined speed to obtain a high impact polypropylene copolymer,
wherein said polymerization is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of said ingredients subjected to polymerization; and
iii) compounding predetermined amounts of said high crystalline polypropylene copolymer obtained in step (i), said high impact polypropylene copolymer obtained in step (ii), a polyolefin elastomer and at least one additive at a speed in the range of 800 rpm to 1200 rpm at a third predetermined temperature to obtain said unfilled polypropylene composition,
wherein said compounding is performed for a time period in the range of 0.04 minutes/kg to 0.15 minutes/kg of said ingredients subjected to compounding.
16. The process as claimed in claim 15, wherein said polyethylene polymer is at least one selected from polyethylene butene and polyethylene octene.
17. The process as claimed in claim 15, wherein said diene polymer is at least one selected from the group consisting of ethylene, butene, isobutene, pentene, hexene, polyethylene octene, decene, acyclic monomers, 2-methyl-1-pentene, 2,3-dimethyl-1-pentene, 4-methyl-1-pentene, 2-methyl-1-butene, cyclopentene, cyclobutene, cyclobutadiene, dicyclopentadiene and hexadiene.
18. The process as claimed in claim 15, wherein
i) said predetermined amount of said polypropylene homopolymer is in the range of 85 mass% to 95 mass% with respect to the total mass of said high crystalline polypropylene copolymer;
ii) said predetermined amount of said polyethylene polymer is in the range of 5 mass% to 15 mass% with respect to the total mass of said high crystalline polypropylene copolymer;
iii) said first predetermined temperature is in the range of 170 °C to 250 °C;
iv) said first predetermined speed is in the range of 500 rpm to 700 rpm; and
v) said first predetermined pressure is in the range of 10 bar to 30 bar.
19. The process as claimed in claim 15, wherein
i) said predetermined amount of said block polypropylene copolymer is in the range of 60 mass% to 80 mass% with respect to the total mass of said high impact polypropylene copolymer;
ii) said predetermined amount of said diene polymer is in the range of 20 mass% to 40 mass% with respect to the total mass of said high impact polypropylene copolymer;
iii) said second predetermined temperature is in the range of 170 °C to 250 °C;
iv) said second predetermined speed is in the range of 500 rpm to 700 rpm; and
v) said second predetermined pressure is in the range of 10 bar to 30 bar.
20. The process as claimed in claim 15, wherein
i) said predetermined amount of said high crystalline polypropylene copolymer is in the range of 15 mass% to 30 mass%;
ii) said predetermined amount of said high impact polypropylene copolymer is in the range of 55 mass% to 70 mass%;
iii) said predetermined amount of said polyolefin elastomer is in the range of 5 mass% to 15 mass%;
iv) said predetermined amount of said additive is in the range of 3 mass% to 7 mass%; and
wherein said mass% of each ingredient is with respect to the total mass of said unfilled polypropylene composition.
21. The process as claimed in claim 15, wherein said third predetermined temperature is in the range of 170 °C to 250 °C.

Dated this 30th day of May, 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