Claims:We claim:
1. A polypropylene based composition comprising:
30-80 wt% of polypropylene homopolymer;
30-80 wt% of polypropylene copolymer;
5-20 wt% of magnesium oxysulfate;
0.5-3 wt% of carbon nanomaterial;
0-3 wt% of nucleating agent;
0.1-0.4 wt% of antioxidant;
0.1- 0.4 wt% of thermal stabilizer; and
0.5-1 wt % of UV stabilizer.

2. The polypropylene based composition as claimed in claim 1, wherein said polypropylene homopolymer is in crystalline form.

3. The polypropylene based composition as claimed in claim 1 to 2, wherein said polypropylene copolymer is in the crystalline form.

4. The polypropylene based composition as claimed in claim 1 to 3, wherein said nucleating agent is calcium pimelate.

5. The polypropylene based composition as claimed in claim 1 to 4, wherein said antioxidant is blend of 67% tris(2,4-ditert-butylphenyl) phosphite and 33% pentaerythritol tetrakis[3-3,5-di-tert-butyl-4-hydroxyphenyl] propionate].

6. The polypropylene based composition as claimed in claim 1 to 5, wherein said thermal stabilizer is a pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl] propionate.

7. The polypropylene based composition as claimed in claim 1 to 6, wherein said UV stabilizer is hindered amine light stabilizers.
8. The polypropylene based composition as claimed in claim 1 to 7, wherein said polypropylene homopolymer is employed in an amount of from 50 to 60% by weight.

9. The polypropylene based composition as claimed in claim 1 to 8, wherein said polypropylene copolymer is employed in an amount of from 30 to 35% by weight.

10. The polypropylene based composition as claimed in claim 1 to 9, wherein said magnesium oxysulfate is employed in an amount of from 5 to 20% by weight.

11. A method of preparation of a polypropylene based composition, said method comprising:
mixing 30-80 wt% of polypropylene homopolymer, 30-80 wt% of polypropylene copolymer, 0.5-2 wt% of carbon nanomaterials and 0.5-2 wt% of nucleating agent in an extruder at a temperature in the range of 190-220°C to form a master batch; and
adding 5-20 wt% of magnesium oxysulfate, 0.5-1 wt % of UV stabilizer, 0.1- 0.4 wt% of thermal stabilizer and 0.1-0.4 wt% of antioxidant at temperature in the range of 190-220°C to said master batch for preparing said polypropylene based composition.

12. The method as claimed in claim 11, wherein said polypropylene homopolymer is in the crystalline form.

13. The method as claimed in claim 11 to 12, wherein said polypropylene copolymer are in the crystalline form.

14. The method as claimed in claim 11 to 13, wherein said nucleating agent is calcium pimelate.
15. The method as claimed in claim 11 to 14, wherein said antioxidant is blend of 67% tris(2,4-ditert-butylphenyl) phosphite and 33% pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl] propionate].

16. The method as claimed in claim 11 to 15, wherein said thermal stabilizer is pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl] propionate.

17. The method as claimed in claim 11 to 16, wherein said UV stabilizer is hindered amine light stabilizers.
, Description:TECHNICAL FIELD
[001] The embodiments herein relates to a formulation of a polypropylene compound having a combination of nanofillers and additives with optimized stiffness-toughness. Further, the embodiments herein relates to a high gloss polypropylene compound to be used as a molded-in-color compound for developing auto exterior trim panels such as appliques and bezels that need a combination of stiffness and toughness.

BACKGROUND
[002] Conventionally, engineering plastics like ABS and PC-ABS were used for molding the aesthetic bezels and appliques in the exterior of a vehicle. Such decorative parts include bottom skid plates, grille bezels and appliques in the vehicle exterior that is prone for pedestrian knee impact and slow speed collision. The parts in addition to being rigid behave in a brittle manner when subjected to impact conditions resulting in sharp fragments that can harm the pedestrian. This calls for having toughened polymers that can be tailored to have adequate stiffness-impact balance.
[003] In addition to the functional requirements (adequate stiffness-impact balance), the bezels and appliques must be aesthetically appealing in terms of the gloss and surface finish. With car increasingly becoming a fashion accessory, the bezels and appliques are crucial style elements whose finish levels and performance need to be durable.
[004] Conventionally, the materials are usually painted/ chrome plated resulting in huge costs. Additionally, the secondary operation of painting / chrome plating causes environmental hazards. Hence, there is a need to have a novel material solution that can meet the functional and aesthetic requirements in addition to being fully recyclable and being environment friendly (replacement of painting / plating).
[005] Polypropylene compounds belong to a unique class of materials that are widely used for bumpers, other exterior parts and in the interiors of a vehicle owing to its low cost, environment friendliness and chemical resistance. Conventionally polypropylene compounds are toughened using an impact modifier and filled with mineral fillers like talc to tailor the stiffness – impact balance to meet the functional requirements of parts used in pedestrian protection system. However, addition of impact modifiers lowers the gloss and aesthetic appeal of the materials and makes the part cheap thereby calling for additional operations like painting. Nanomaterials and unique nucleating agents are found to be beneficial in overcoming the above-mentioned challenges in addition to offering scratch resistance to the parts. Addition of nanomaterials bestows additional conductive properties to the parts that can be useful for rendering special effects.

SUMMARY
[006] Accordingly, an object of embodiments herein is to provide a high gloss polypropylene-based composition which is useful for the manufacturing of the automotive exterior plastic parts with aesthetic requirements.
[007] Another object of embodiments herein is to provide a polypropylene-based composition with optimized stiffness-toughness in balance.
[008] An additional object of the embodiments herein is to provide a polypropylene-based composition which is light weight in nature and can reduce the part weight of exterior trim panels. It can also be colored to give customer appeal and has better scratch and mar resistance.
[009] Another object of the embodiments herein is to provide a polypropylene-based composition whose unique combination meets the aesthetic, performance and durability requirements of exterior trim panels that need high gloss for superior aesthetics.
[0010] The above objects of the embodiments herein have been met by a polypropylene based composition comprising:
30-80 wt% of polypropylene homopolymer;
30-80 wt% of polypropylene copolymer;
5-20 wt% of magnesium oxysulfate;
0.5-3 wt% of carbon nanomaterial;
0-3 wt% of nucleating agent;
0.1-0.4 wt% of antioxidant;
0.1- 0.4 wt% of thermal stabilizer; and
0.5-1 wt % of UV stabilizer.
[0011] The method of preparation of a polypropylene based composition, comprising: mixing 30-80 wt% of polypropylene homopolymer, 30-80 wt% of polypropylene copolymer, 0.5-2 wt% of carbon nanomaterials and 0.5-2 wt% of nucleating agent in an extruder at a temperature in the range of 190-220°C to form a master batch; and adding 5-20 wt% of magnesium oxysulfate, 0.5-1 wt % of UV stabilizer, 0.1- 0.4 wt% of thermal stabilizer and 0.1-0.4 wt% of antioxidant at temperature in the range of 190-220°C to the master batch for preparing the polypropylene based composition.

DETAILED DESCRIPTION
[0012] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0013] The embodiments herein achieve high gloss polypropylene-based composition which is useful for the manufacturing of the automotive exterior plastic parts with aesthetic requirements.
[0014] The polypropylene nano-compound mentioned in this work consists of nanomaterials and additives that work to give adequate stiffness - toughness balance at high gloss levels.
[0015] Conventional high gloss polypropylene materials have high stiffness but lack toughness because of the absence of elastomer ingredients that usually toughen the matrix. However, this work relates to formulating the polypropylene compound using additives that work to toughen the resin whilst the nanomaterials stiffen the compound and impart the desired scratch resistance.
[0016] As elastomers are not there in the formulation, the gloss levels are still maintained. This unique combination meets the aesthetic, performance and durability requirements of exterior trim panels that need high gloss for superior aesthetics.
[0017] The polypropylene based composition comprising 30-80 wt% of polypropylene homopolymer; 30-80 wt% of polypropylene copolymer; 5-20 wt% of magnesium oxysulfate; 0.5-3 wt% of carbon nanomaterial, 0-3 wt% of nucleating agent; 0.1-0.4 wt% of antioxidant; 0.1- 0.4 wt% of thermal stabilizer; and 0.5-1 wt % of UV stabilizer. The composition can be prepared by mixing 30-80 wt% of polypropylene homopolymer, 30-80 wt% of polypropylene copolymer, 0.5-2 wt% of carbon nanomaterials and 0.5-2 wt% of nucleating agent in an extruder at a temperature in the range of 190-220°C to form a master batch; and adding 5-20 wt% of magnesium oxysulfate, 0.5-1 wt % of UV stabilizer, 0.1- 0.4 wt% of thermal stabilizer and 0.1-0.4 wt% of antioxidant at temperature in the range of 190-220°C to said master batch for preparing said polypropylene based composition
[0018] The formulation which will give the adequate stiffness – impact balance, be light in weight and high aesthetics (high gloss and scratch resistance) is given below.

Ingredient Wt %
High crystalline polypropylene homopolymer 30 - 80%
High crystalline polypropylene copolymer 30 - 80%
Magnesium oxysulfate whisker 5 - 20%
Carbon nanotube / Graphene / nano Calcium carbonate 0.5 – 2%
Calcium Pimelate nucleating agent 0.5 – 2%
Process antioxidant 0.1 – 0.4%
Long term thermal stabilizer 0.1 – 0.4%
UV stabilizer 0.5 – 1%

[0019] More specifically, the formulation can be finetuned to have the following composition
Ingredient Wt %
High crystalline polypropylene homopolymer 50 - 60%
High crystalline polypropylene copolymer 30 - 35%
Magnesium oxysulfate whisker 5 - 10%
Carbon nanotube / Graphene / nano Calcium carbonate 0.5 – 2%
Calcium Pimelate nucleating agent 0.5 – 2%
Process antioxidant 0.1 – 0.4%
Long term thermal stabilizer 0.1 – 0.4%
UV stabilizer 0.5 – 1%

[0020] The method of preparation of a polypropylene based composition comprising mixing 30-80 wt% of polypropylene homopolymer, 30-80 wt% of polypropylene copolymer, 0.5-2 wt% of carbon nanomaterials and 0.5-2 wt% of nucleating agent in an extruder at a temperature in the range of 190-220°C to form a master batch; and adding 5-20 wt% of magnesium oxysulfate, 0.5-1 wt % of UV stabilizer, 0.1- 0.4 wt% of thermal stabilizer and 0.1-0.4 wt% of antioxidant at temperature in the range of 190-220°C to said master batch for preparing said polypropylene based composition. The polypropylene homopolymer and copolymer used in the composition is in the high degree of crystalline form and the nucleating agent is calcium pimelate. Calcium pimelate acts as a very effective nucleating additives that work on altering the crystalline state of the material thereby giving superior toughness and ease of processing in conventional processing machines. More specifically, the compound has Graphene / carbon nanotube / calcium carbonate nanomaterials. This compound is light weight in nature and can reduce the part weight of exterior trim panels. It can also be colored to give customer appeal and has good scratch and mar resistance. The antioxidant is blend of 67% tris(2,4-ditert-butylphenyl) phosphite and 33% pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl] propionate] and thermal stabilizer is blend of pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl] propionate.
[0021] A summary of the properties for the material compounded using a twin-screw extruder is reproduced below.

Sr. No. PROPERTIES UNITS SPECIFICATION TEST METHOD
1 Density g/cc Max 1 ASTM D792
2 Melt Flow Rate at 230 ?C / 2.16 Kg g/10 min Min 30 ASTM D1238
3 Tensile Strength at Yield MPa Min 25 ASTM D638
4 Elongation at Yield % Min 5 ASTM D638
5 Flexural Strength MPa Min 30 ASTM D790
6 Flexural Modulus MPa Min 1400 ASTM D790
7 Izod Impact Strength (Notched)
i) At 23 ?C
ii) At –30 ?C

kJ/m2
kJ/m2

Min 25
Min 4 ASTM D256

[0022] The polypropylene compound can replace conventional materials like ASA, PC-ASA and painted ABS in demanding applications like tailgate applique and decorative parts in the exterior of a vehicle. Such decorative parts include bottom skid plates, grille bezels and appliques in the vehicle exterior that is prone for pedestrian knee impact among others.
[0023] The technical advantages of the high gloss polypropylene-based composition are as follows. The polypropylene-based composition is useful for the manufacturing of the automotive exterior plastic parts with aesthetic requirements. The polypropylene-based composition has optimized stiffness-toughness in balance. The polypropylene-based composition is light weight in nature and can reduce the part weight of exterior trim panels. It can also be colored to give customer appeal and has good scratch and mar resistance. The polypropylene-based composition whose unique combination meets the aesthetic, performance and durability requirements of exterior trim panels that need high gloss for superior aesthetics.
[0024] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the spirit and scope of the embodiments as described herein.