Description:PROCESS OF MANUFACTURING RADIATOR END TANK USING A LOW-DENSITY POLYMER-BASED BLENDED MATERIAL

Field of the invention:

The present invention generally relates to radiators and more particularly, to a process for manufacturing radiator end tanks using a low-density polymer-based blended material.

Background of the invention:

Generally, the radiators are designed to dissipate the heat which is absorbed by a coolant from an engine. The radiator consists of a large number of water tubes that provide a large area to contact with an atmosphere. The radiator normally consists of a radiator core or cooling matrix comprising water in tubes and a large cooling area that is connected to a receiving tank or end tank at the top and a dispensing tank at the bottom. The radiator end tanks (RET) could be made of plastic, aluminum, copper, brass, or any other materials. But whatever materials they may be RETs are susceptible to various types of damage due to extreme heat and vibrations. To survive all such issues, the RETs must have excellent heat and hydrolysis resistance as well as strong dimensional stability.

The radiator end tanks made of polyamide material (PA 66) are capable of sustaining thermal properties at 100-130 °C. Polyamide materials have very good heat deflection temperature (HDT) resistance properties and also have good hydrolysis resistance properties. But the properties of the Polyamide materials PA 66 30 GF were found to be over-engineered for the radiator end tank in a CAE analysis. Similarly, PA66 GF30 is also overpriced compared to the other engineering plastics available in the market. Moreover, the density of PA 66 GF30 material is higher which leads to higher part weight.

Moreover, the studies on various plastic materials show that none of the materials was found suitable for RET due to poor mechanical properties or might cost.

Accordingly, there exists a need to provide a manufacturing process for the radiator end tank using a blended material for cost-effectiveness to overcome the drawbacks in the prior art.

Object of the invention:

An object of the invention is to manufacture the radiator end tank using a cost-effective material with excellent heat and hydrolysis resistance as well as strong dimensional stability.

Summary of the invention

Accordingly, the present invention provides a process for manufacturing a radiator end tank using a blended material. The blended material includes nylon and polypropylene in a predefined ratio. Specifically, nylon and polypropylene are used in a 50-70:30-50 ratio. The manufacturing process comprises steps of preparing a mold, conveying blended material, heating blended material at a predefined temperature, injecting blended material into the mold, cooling the mold, and extracting the prepared radiator end tank from the mold. The blended material provides excellent heat and hydrolysis resistance as well as strong dimensional stability.

Detailed description of the invention:

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiments.

The present invention provides a process for manufacturing a radiator end tank (RET). A blended material is used for manufacturing the radiator end tank (RET). The blended material is obtained by processing the polymers nylon (polyamide) and polypropylene (PP) in a predefined ratio. In an embodiment, nylon and polypropylene are blended in a 50-70:30-50 ratio. The blended material is selected based on the factor of safety available in design and its cost-effectiveness.

The process for manufacturing radiator end tanks comprises the steps of preparing a mold for a radiator end tank, conveying a plurality of pellets of a blended material through a hopper, heating the blended material at a plurality of temperature regions preset at a particular temperature respectively, injecting the molten blended material into the mold through an injection nozzle, cooling the mold at predefined temperature for a predefined duration, and extracting the prepared radiator end tank from the mold.

The plurality of temperature regions is preset at temperatures ranging from 170°C – 200 °C. The temperature of the injection nozzle can be set from 200 °C – 220 °C. The cooling temperature for mold can be between 50 – 70 °C. Further, the mold is cooled for at least 20 to 50 seconds.

In a preferred embodiment, the plurality of temperature regions includes at least four temperature regions, a first temperature region is preset between 190 °C, a second temperature region is preset at 185 °C, a third temperature region is preset at 180 °C, and a fourth temperature region is preset at 180 °C. The temperature of the injection nozzle is 210 °C. The mold is cooled at 60 °C for at least 30 seconds.

The invention is further illustrated hereinafter by means of examples.

Example:

Experiments were carried out using PP material with strong heat stabilizers for the radiator end tank (RET). The polypropylene showed a strong heat stabilizing property but the material was failing from the tank rib due to insufficient toughness and the property was not satisfactory. Hence, experiments were performed with different formulations of nylon and PP to achieve desirable properties. Table 1 shows the blend of the materials nylon and PP in different combinations and their material properties.

Table 1:
Material properties with various combination
Properties
Parameters
Unit Composite Material (PP+LGF)
60:40 70:30
Mechanical Properties Tensile stress MPa 130 110
Elongation % 2.1 2.3
Charpy Impact KJ/m² 26 19
Thermal Properties HDT ºC 163 160
Physical Properties Density g/cm3 1.2 1.09
From Table 1, it is observed that formulations with PP and long glass fibers in the ratio 60:40, provide the better properties while 70:30 PP and long glass fiber composite have slight inferior properties. While PP and long glass fibers (LGF) in 60:40 ratio were found to be best suitable for the radiator end tank (RET). In an alternate method, PP and LGF in 50:50 ratio provide slight better properties but there was no cost advantage.
Table 2:
The following table 2 provides the mechanical properties of PP40LGF (Polypropylene 40% Long glass fiber) composite material in DAM conditions, heat ageing, and coolant ageing properties.
1. Material DAM (Dry as molded) Properties

Sr. Parameter

Test methods PP40LGF
Dry
1 Filler Content (%) 40
2 Density at 23 0C (g/cm³) 1.2
3 Tensile modulus (M Pa) ISO 527-I 9400
4 Tensile stress at break(Ultimate Tensile Strength UTS) (M Pa) ISO 527-I 145
5 Tensile elongation at break (%) ISO 527-I 2.1
6 Flexural modulus (M Pa) ISO 178 8900
7 Flexural strength (M Pa) ISO 178 200
8 Charpy notched impact strength (kJ/m2) 230C ISO 179-I 28
9 Heat Deflection Temp (0C) @0.45 M Pa ISO 75-I 164 0.45MPa

2. Heat ageing properties of PP40LGF at 130 °C.

Heat ageing at 130°C.
0 250 500 1000 1500 2000
Tensile Stress at break (M Pa) 124 129.3 114.1 113.8 108 114.08
Elongation (%) 2.1 1.9 1.9 2.1 2.1 2.1
Tensile Modulus (M Pa) 9200 8315 10085 9128 9078 8268
Notched Izod Impact Strength (KJ/m²) 21.3 23.5 21.3 21.1 21 21.63

3. Coolant ageing properties of PP40LGF at 130 °C.

Coolant ageing at 130°C.
0 250 500 1000 1500 2000
Tensile Stress at break(M Pa) 124 124.1 128.4 117.4 119.9 115.83
Elongation (%) 1.8 1.8 1.9 1.9 2 1.6
Tensile Modulus(M Pa) 9200 8097 7704 7622 7853 7580
Notched Izod Impact Strength(KJ/m²) 21.3 21.6 21.6 21.5 22.2 18.19

Dry as molded is the condition of the sample just after molding the test specimen.

Air ageing/ Heat ageing is the condition in which the test specimen is exposed to the hot air at 130°C for 2000 hrs and the measurement of the mechanical properties is done at room temperature(23°C) at 0, 250, 500, 1000, 1500 and 2000 hrs. of ageing.

Coolant ageing is the condition of the sample in which the test sample is immersed inside the 50:50 Ethylene Glycol: Water mixture at 130°C for 2000 hrs and the measurement of the mechanical properties is done at room temperature (23°C) at 0, 250, 500, 1000, 1500 and 2000 hrs. of ageing.

Table 3:

The following table provides a comparison of coolant ageing material properties at 130°C of the composite material PP40LGF and Polyamide66 30% glass filled (PA66GF30).
Coolant ageing at 130°C and testing at 23°C
Properties
Coolant Ageing @ 130°C PA66GF30 Coolant Ageing @ 130°C PP40LGF
Ageing Hrs Mechanical Properties UTS Ultimate Tensile Strength(M Pa)
0 180 124
500 90 128
1000 85 117
1500 80 120
2000 70 116

From the above table no:3, it is observed that PP40LGF has a better tendency to retain its mechanical properties at 130°C, even at 2000 hrs of coolant aging in comparison to the tendency of Polyamide 66 30% glass-filled (PA66GF30) to retain its mechanical properties at 2000 hrs.

Advantages of the invention:

1. The blended material provides excellent heat and hydrolysis resistance as well as strong dimensional stability.
2. The blended material is economical and the extraction of polypropylene (PP) material from crude petroleum is easy as compared to the nylon material. Hence electric energy can be conserved thereby reducing carbon footprint emissions.
3. Polypropylene (PP) is an eco-friendly material from a recycling point of view.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the claims of the present invention.

, Claims:We Claim:

1. A process for manufacturing radiator end tanks using a blended material, comprising the steps of:
a. preparing a mold for a radiator end tank;
b. conveying a plurality of pellets of a blended material through a hopper;
c. heating the blended material at a plurality of temperature regions, each region preset at a particular temperature ranging from 170 – 200 °C;
d. injecting the molten blended material into the mold through an injection nozzle;
e. cooling the mold at a temperature from 50 - 70 °C for a predefined duration; and
f. extracting the prepared radiator end tank from the mold,
wherein the blended material for a radiator end tank having nylon and polypropylene with a ratio of 50-70:30-50 respectively.

2. The process for manufacturing radiator end tanks as claimed in claim 1, wherein the temperature of the injection nozzle is ranging from 200 °C – 220 °C.

3. The process for manufacturing radiator end tanks as claimed in claim 1, wherein the mold is cooled for at least 20 to 50 seconds.

Dated this on the 31st day of October, 2022

Prafulla Wange
(Agent of Applicant)
(IN/PA-2058)