Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See section 10, Rule 13]

A BRACKET CONTAINING POLYPROPYLENE AND LONG GLASS FIBERS

MAHINDRA & MAHINDRA LIMITED, A COMPANY REGISTERED UNDER THE INDIAN COMPANIES ACT, 1913, HAVING ADDRESS AT MAHINDRA RESEARCH VALLEY, MAHINDRA WORLD CITY, PLOT NO: 41/1, P.O. – ANJUR, CHENGALPATTU – 603004, TAMIL NADU, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF INVENTION
The invention relates to a bracket containing polypropylene and long glass fibers, particularly a bracket for an automotive.

BACKGROUND OF THE INVENTION
Automobiles primarily use metal such as steel in the area of BIW (Body in White)/doors, brackets, hinges etc. During operation, frequent steel to steel contact takes place thereby resulting in squeaking, rattling noise and vibration of these parts that modify the NVH (Noise, vibration, and harshness) of passenger vehicles. The noise is loud every time there is a jerk to the automobile during braking or when the door is operated, which causes discomfort to passengers and suggests replacement of parts which is cost intensive.

Further, with the emergence of electric vehicles (EV), there is a constant search of solutions to reduce the body weight of the car to achieve maximum optimum performance such as speed, fuel economy from the EV’s. Thus, there is a need of components, particularly brackets that have reduced the noise and vibrations, are light in weight and at the same time having suitable mechanical properties to be used in vehicles, thereby eliminating passenger discomfort and having a prolonged product life.

SUMMARY OF THE INVENTION
In an aspect, the invention relates to bracket consisting of 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt.

In another aspect, the invention relates to a composition consisting of 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers having length in a range from 5-10 mm, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt.

In another aspect, the invention relates to a process for preparation of a composition. The process comprises mixing 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers having length in a range of 5-10 mm, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt. The mixture is processed at a temperature in a range from 190°C to 230°C and then extruded through a co-rotating twin screw extruder.

BRIEF DESCRIPTION OF DRAWING
Figure 1: Rear Door pull cup bracket as per the present invention.
Figure 2: Front Door pull cup bracket as per the present invention.

DETAILED DESCRIPTION OF THE INVENTION
The present invention addresses the problem of metal brackets associated with noise and vibration by providing a bracket comprising polypropylene long glass fiber thermoplastic composite material.

In an aspect the invention relates to bracket consisting of 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt.

Polypropylene is a base material, and a catalyst based polypropylene material is preferred to make the thermoplastic composite.

The glass fibers are long glass fibers having a length of 5-10 mm, preferably the length of glass fibers is 8-10 mm. The glass fibers provide reinforcement to the polymer by acting as load bearing element thereby improving the mechanical properties of the composite such as stiffness, strength etc. Glass fibers less than 5 mm in length do not provide strength. While glass fibers having length of more than 10 mm cause difficulty during processing.

The additives comprise a coupling agent, a compatibilizer, an antioxidant and a heat stabilizer.

Coupling agent and compatibilizer are substances for treating a surface so that bonding occurs between the materials. These additives enable mixing of two dissimilar polymers together which further enhance the material properties. The coupling agents and compatibilizers are selected from silane-based compounds (KH 550, KH 560), polyolefin-based compounds (POLYBOND 3200, POLYBOND 3002), maleic anhydride based compatibilizer compounds, multiblock ethylene–octene copolymers (OBC), two statistical ethylene–octene copolymers (EO), two propylene–ethylene copolymers (P/E), a styrene block copolymer (SBC), a metallocene compound such as Ferrocene or a combination thereof.

Antioxidants and heat stabilizers are substances which protects a polymer against oxidation, whether during processing or in service life. These additives prevent polymers from degrading thermally. Examples of antioxidants and heat stabilizers include Irganox B225 (blend of phenolic antioxidant and a phosphite antioxidant), amine based compounds or a combination thereof.

The bracket can be of any desired shape/geometry. In a preferred embodiment, the bracket is L-shaped. The bracket has a thickness in a range of 2.2 mm to 2.8 mm.

The bracket has merging ribs at the point of intersection of the L-shape, to attain load bearing capacity. The bracket preferably has 7 to 8 ribs. Each rib has a thickness in a range of 1.2 mm to 1.7 mm and a height in a range from 10 mm to 28 mm. The height of the ribs depends on the location of the bracket. The bracket is preferably a door pull cup bracket for an automotive where it is positively mounted on a car body where it provides a resting place for the door trim cup holder.

In a preferred embodiment, the rear door bracket has 8 ribs, each rib having a thickness in a range of 1.2 mm to 1.7 mm and height in a range of 25 mm to 28 mm (Figure 1). The front door bracket has 7 ribs, each rib having a thickness in a range of 1.2 mm to 1.7 mm and height in a range of 10 mm to 15 mm (Figure 2).

The bracket is light weight and has no squeak and rattling noise in comparison to the metal based brackets. Also, the bracket has a sound transmission loss in a range of 2-4 dB (decibels). This shows that the bracket provides significant sound dampening and thereby improves the NVH performance of the automotive. Also, the light weight of the bracket contributes to reduction in body weight of automotive and thereby better fuel economy. The bracket is also recyclable and avoids load on environment by not ending up in landfills and supports circular economy.

In another aspect, a process for preparation of the bracket is described. The process comprises mixing polypropylene, glass fibers, additives and optionally a pigment. The mixture is processed at a temperature in a range from 190°C to 230°C and then extruded through a co-rotating twin screw extruder. The composition was then injection moulded into a bracket.

The process of preparation is simple and consumes less energy, thereby provides ease of processibility.

In another aspect, the invention relates to a composition comprising 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers having length in a range from 5-10 mm, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt.

In another aspect, the invention relates to a process for preparation of a composition comprising mixing 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers having length in a range of 5-10 mm, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt. The mixture is processed at a temperature in a range from 190°C to 230°C and then extruded through a co-rotating twin screw extruder.

EXAMPLE
Polypropylene composition as described in Table 1 was used in preparation of a door pull cup bracket.

Table 1
Component Amount (% wt.)
Sample 1 Sample 2 Sample 3 Sample 4
Polypropylene 57 58 59 60
Glass fibers (length 8-10 mm) 40 39 38 37
Coupling agent and Compatibilizer 1.5 1.5 1.5 1.5
Irganox B225 1 1 1 1
Pigment 0.5 0.5 0.5 0.5

Process for preparation: The components described in Table 1 were mixed and the mixture was processed at a temperature in range of 190°C to 230°C and then extruded through a co-rotating twin screw extruder to prepare a composition.

The compositions were injection moulded into brackets having a thickness of 2.5 mm. As shown in Figure 1, the rear door bracket has 8 ribs, each rib having a thickness in a range of 1.2 mm to 1.7 mm and height in a range of 25 mm to 28 mm.
As shown in Figure 2, the front door bracket has 7 ribs, each rib having a thickness in a range of 1.2 mm to 1.7 mm and height in a range of 10 mm to 15 mm.

The brackets were evaluated for density, elastic modulus, Buzz, Squeak and Rattle (BSR), Sound Transmission Loss (STL) and the results are shown in Table 2.

Table 2
Sr.no Properties Test method Unit Typical properties
1 Tensile Strength at yield ASTM D 638 MPa 130
2 Elongation at Break ASTM D 638 % 2
3 Flexural strength ASTM D 790 MPa 168
4 Elastic modulus ASTM D 790 MPa 7500
5 Heat deflection
temperature, 0.45 MPa ASTM D 648 ° C 162
6 Izod impact at 23°C ASTM D 256 KJ/m² 15
7 Ash content ASTM E1131 % 39
8 Density ASTM D792 g/cm³ 1.3 Max
9 Sound transmission Loss ---- dB 2 - 4

As seen from the results, the brackets had a density of maximum 1.3 g/cm3 which is significantly lower than metal brackets which have a density of around 7.8 g/cm3. Thus, the brackets were light in weight in comparison to metal brackets.

The brackets had a STL in a range of 2-4 dB suggesting that it had no buzz, squeak and rattle and provided high sound dampening which cannot be achieved with metal brackets due to metal to metal contact. Thereby the polypropylene based brackets provided an improved NVH performance when used in automotives.

The results for tensile strength and elastic modulus suggest that the brackets were capable of sustaining a designed load of 40 Kgf and thereby making it suitable for use in automotives.

The foregoing description of the disclosure has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to a person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.

, Claims:We Claim:

1. A bracket consisting of 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt.

2. The bracket as claimed in claim 1 wherein the glass fibers have length in a range of 5-10 mm.

3. The bracket as claimed in claim 1 wherein the additives comprise a coupling agent, a compatibilizer, an antioxidant and a heat stabilizer.

4. The bracket as claimed in claim 3 wherein the coupling agent and compatibilizer are selected from silane based compounds, polyolefin based compounds, maleic anhydride based compounds, multiblock ethylene-octene copolymers, two statistical ethylene-octene copolymers, two propylene-ethylene copolymers, a styrene block copolymer, a metallocene compound or combination thereof; and
the antioxidant and heat stabilizer are selected from phenolic antioxidants, phosphite antioxidants, amine based compounds or a combination thereof.

5. The bracket as claimed in claim 1 for an automotive, having a thickness in a range of 2.2 mm to 2.8 mm and having 7 to 8 ribs, each rib having a thickness in a range of 1.2 mm to 1.7 mm and height in a range of 10-28 mm.

6. The bracket as claimed in claim 1 having sound transmission loss in a range of 2-4 dB.

7. A process for preparation of the bracket as claimed in claim 1, the process comprising:
mixing polypropylene, glass fibers, additives and optionally a pigment;
processing the above mixture at a temperature in a range from 190°C to 230°C;
extruding the mixture through a co-rotating twin screw extruder; and
injection moulding the composition.

8. A composition consisting of 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers having length in a range of 5-10 mm, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt.

9. A process for preparation of a composition, the process comprising:
mixing 57% wt. to 60% wt. of polypropylene, 37% wt. to 40% wt. of glass fibers having length in a range of 5-10 mm, 2% wt. to 3% wt. of additives and optionally a pigment up to 0.5% wt.;
processing the above mixture at a temperature in a range from 190°C to 230°C; and
extruding the mixture through a co-rotating twin screw extruder.

Dated this 21st day of March, 2023
For Mahindra & Mahindra Limited
By their Agent

(GIRISH VIJAYANAND SHETH) (IN/PA 1022)
KRISHNA & SAURASTRI ASSOCIATES LLP