FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)

“INJECTION MOLDED AUTOMOTIVE COMPONENT MADE FROM POLYESTER RESIN COMPOSITES AND PROCESS OF MANUFACTURING IT”
1. MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R & D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C., SATPUR, NASHIK – 422 007,
MAHARASHTRA, INDIA.
2. RENAISSANCE CORPORATION LIMITED
AN INDIAN COMPANY
101-B, MEHTA ESTATE, CHAKALA, ANDHERI-KURLA ROAD, ANDHERI (EAST),
MUMBAI- 400 093,
MAHARASHTRA, INDIA.

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES AND ASCERTAINS THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
FIELD OF INVENTION:

The present invention relates to an injection molded automotive component made from polyester resin composites. More particularly the present invention relates to an injection molded automotive component made from a novel blend by combining recycled polyethylene terephthalate (RPET), glass fiber and special additive in a particular proportion for its use in automotive applications such as engine cover.

BACKGROUND OF THE PRESENT INVENTION:

Polyethylene terephthalate (PET) bottles, films, fibers and etc. are generally thrown out as incombustible garbage after usage. Being synthetic polymeric material it does not get degraded and creates immense problems and hazards for environment. Therefore, it was aimed to utilize these consumer used PET products as one of the raw material to produce an automotive component such as the engine cover.

Conventionally polyamide based resin with glass fiber reinforcement material is used for engine covers in automotive vehicles. As a part of working towards the greener environment and also like many industries are working towards the environment friendly technologies, we have developed formulations to use Recycled PET as environmentally progressive source for raw material.

Variety of automotive applications from recycled PET bottles, films, fibers, etc. is available in public domain which has met with varying degrees of success.

American patent No. US.6800685 discloses polyester resin composition for engine peripheral parts wherein recycled resins as of PET bottles can also be used as the polyester resin for the resin composition. However, because these polyester resins are often designed to have high molecular weights, they may have low crystallizability and fluidity and thus may not be suitable for injection molding.

European patent No. EP.1273627 describes recycled polyester resin composition and molded articles thereof wherein recycled polyester resin composition contains 100 parts by weight of a recycled polyester resin, 0.5 to 20 parts by weight of a lactone polymer, 0.5 to 30 parts by weight of an epoxidized diene-based block copolymer and optionally 0.5 to 30 parts by weight of a polyolefin resin; and an article molded from the composition. This composition exhibits improved formability in terms of injection molding and extrusion molding, and the molded article has excellent mechanical strength.

Patent No. US.6521155 teaches a process for manufacturing a plastic pipe from recycled crushed PET as starting material wherein starting material is kneaded under the influence of heat while removing moisture there from so as to prevent hydrolysis of the PET material and thereafter feeding the mixture to an extruder and passing the extruded mixture to a corrugators while cooling at a temperature gradient of between – 10 degree centigrade per minute and – 50 degree centigrade per minute so as to form a crystalline plastic pipe.

The use of polyester resin from recycled PET bottles in the manufacture of automotive components especially for larger parts like engine cover has certain process difficulties like mold filling in injection molding method as PET bottles are produced from high viscous PET resin in blow molding process. But for making engine cover part by injection molding process, it required the relatively lower viscosity. If only lower viscosity material used it may not provide required mechanical and thermal property, if high viscosity resin only used it may create process difficulties for injection molding.

To overcome this issue, the present invention provides a novel solution comprising of two different Intrinsic Viscosity (IV) of PET resins that provide the required process feasibility and properties; wherein both IV PET resins are obtained from consumer used PET products waste.

The recycled PET material exhibits poor mold-ability, and therefore it is difficult to form the material into larger molded articles by means of injection molding because the molten resin does not flow readily and make it difficult to remove from the mold after forming. These problems cause major difficulties, particularly in manufacture of large moldings such as engine cover with a projected area. To eliminate these difficulties the present invention provides a novel solution to increase its fluidity thereby improving its formability during injection molding.

OBJECTIVES OF THE PRESENT INVENTION:

The main objective of the present invention is to provide an injection molded automotive component particularly engine cover made from recycled polyethylene terephthalate (RPET) based composites.

Another object of the present invention is to provide a novel polyester resin composite formulation, comprising two different intrinsic viscosity (IV) of polyethylene terephthalate (PET) resins both obtained from recycling of different types of consumer used wastes products made-up of PET, for automotive components

Another object of the present invention is to impart desired fluidity (lower viscosity) to recycled PET thereby improving its formability/mold-ability during injection molding.

Still another object of the present invention is to provide an injection molded engine top cover from recycled polyethylene terephthalate (RPET) which is vibration resistant in higher frequencies, highly stiff, higher heat resistant with good impact properties.

Further object of the present invention is to provide a process of manufacturing a novel composite of RPET with additives suitable for automotive applications particularly engine top cover.

Still further object of the invention is over come the drawbacks of prior art concepts.

DESCRIPTION OF THE FIGURES:

Further objectives and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein,

Figure 1 shows the representative process of recycling waste/consumer used PET bottles to obtain PET granules.

Figure 2 shows the representative processing of end product of Fig.1 to achieve a novel composition.

Figure 3 is the flow chart of obtaining engine top cover from the waste PET bottles.

Figure 4 shows the engine top cover made form a novel composition in accordance with the present invention.

Figure 5 shows the vibration test set up of the component of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION:

The polyester obtained from waste PET bottles normally has higher viscosity. For manufacturing injection molded engine top cover and like automotive components where its thermal and mechanical properties plays a significant role, the composition need to have relatively lower viscosity. Conventionally the flow improvement of resins obtained from waste PET is achieved by addition of flow modifiers, plasticizers, lubricants, addition of other polymeric resins with the formulations. Also the good mold filling could be achieved by using higher process temperature and parameters.

The present invention provides a novel composition for engine top cover comprising combination of two different Intrinsic Viscosity (IV) of PET resins that provide the required process feasibility and properties wherein two IV resins recycled PET (RPET) are obtained from recycling of consumer used wastes, which are two different types of PET products like Bottles & films or fibers.

In accordance with the present invention injection molded automotive component particularly engine top cover is made from environmentally progressive polyester composites, comprising of at least a polyester, Glass filler, polyolefin based Graft Copolymer, low molecular weight epoxy additive, metal alkyl sulphonate derivatives based antistatic agents, thermal stabilizers, process stabilizers and antioxidant additives wherein polyester composite comprises combination of two different IV resins of recycled PET. A novel polyester resin composition for engine top cover essentially comprises of (a) 55-92% by weight combination of two different IV polyesters having the IV range of 0.1 - 1.5 , both are obtained from recycling of two different types of PET product waste; (b) 5-40% by weight of glass filler; (c) 0.05% – 1 % by weight of stearate based additive; (d) 0.02 - 5% by weight of anti static agent from metal alkyl sulphonate derivatives; and (e) 0.05% - 3 % by weight of low molecular weight epoxy additive; wherein glass filler imparts the stiffness and mechanical properties to the product, polymer graft copolymer imparts ductility to the product. This novel composition takes care of the desired thermal and mechanical properties required for the engine top cover. The filler used in this formulation is glass fiber (silica based) however the fillers like talc, mica, nano fillers or its combination can also be preferred.

Injection molded automotive component made from polyester composites, comprising of at least a polyester, glass filler, epoxy additive, antistatic agents, thermal stabilizers, process stabilizers and antioxidant additives; wherein polyester comprises combination at least two different IV of polyesters, preferably recycled poly ethylene terephthalate (RPET) resin 55-92% by weight and the RPET resin having the IV range from 0.1 - 1.5; most optimized range of glass filler is 22 - 36 % by weight; epoxy additive of low molecular weight (100 to 3000 gram/mole) is 0.05 to 3% by weight; antistatic agents are from metal alkyl sulphonate derivatives and is 0.02 to 5% by weight; 0.05 to 1% by weight of stearate based additive. Polyester composites can be prepared by combining RPET with different polymeric resins obtained from bio-derived, petroleum derived, consumer and industrial waste recycled sources; wherein polymeric resins is olefins, amides, esters, carbonates, imdies, ethers, styrenes, dienes, and acrylics; and resin chain architect is graft, oligomer, elastomers, rubber, reactive, crosslinkable, curing polymers dendrimers, ionomers, core shell polymer, monomer, copolymer, ter polymer, star or nano polymer related types.

The above mentioned resins, modifiers, additives combinations are used to make engine cover component, which provided the required injection molding process feasibility like good flow, easy ejection from mold cavity, application and functional related properties like vibration resistance, tensile strength, stiffness, impact, toughness, long term heat resistance, high heat deflection temperature, hydro stability, anti dust properties. Some the basic and special property like vibration resistance are obtained from the novel composition are as mentioned below.

Table 1 Test results of the component obtained as per the ASTM tests.
Sr.No. Typical Resin Properties Unit ASTM Method Test results obtained
1. Density Gms/cc D792 1.57
2. Melting Point ˚C 255
3. Heat Deflection Temp.@0.45Mpa ˚C D648 210
4. Melt Flow Index 285 Deg.C/1.26 Kg Load Gms/10 Min D238 78.60
5. Tensile Strength Yield Kg/Cm2 D638 708
6. Elongation % D638 9
7. Flexural Strength Kg/Cm2 D790 890
8. Impact Strength (N) Kg cm/cm D256 10.25
9. Mould Shrinkage % 0.1
10. Filler % D2584 19.8
11. Warpage % Nil

Vibration Resistance Test:

The molded engine component fixed on the surface of vibrator, the test has been conducted for 135 hrs , at different frequencies like 35,65 ,73 Hz. The test has been conducted in X, Y, Z directions. Fig.5 shows the vibration test set up of the component.

Observation: After the vibration test the sample does not show any deformation and no crack, no loose fixing observed. This is due to the dimensional stability and good mechanical properties of the molded component. The component manufactured by this formulation and process is vibration resistant at higher frequency of 73 Hz, has high ductility, impact, stiffness, thermal resistance and long term heat ageing resistance.

In accordance with the present invention, a novel composition from the polyester resin with combination of two different IV polyester resin are not particularly limited to engine cover. The invention can be used for other automotive and non automotive applications with or with out addition of other additives, stabilizers, fillers, modifiers.

The polyester composites also can be prepared by RPET with combination of different polymeric resin obtained from bio derived, petroleum derived, consumer and industrial waste recycled sources. This combination resin could be olefins, amides, esters, carbonates, imdies, ethers, styrenes, dienes, and acrylics. These mentioned resin chain architect can be graft, oligomer, elastomers, rubber, reactive, crosslinkable, curing polymers dendrimers, ionomers, core shell polymer, monomer, copolymer, ter polymer, star and nano polymer related types.

The recycled granule / chips obtained as the end product of the process shown in Fig. 1 will not have the characteristics of virgin raw material as it passes through very heated cycle and looses its mechanical strength. And therefore can not be used as such where strength and other essential properties like UV stabilizers, heat resistance and fire retardant is required. Therefore a fortification is to be done to this material to enhance for implicate in engineering application as shown in Figure 2. The fortification is followed by compounding by adding some chemical modifiers and reinforcing by adding some filler and chemical agents as shown in Figures 2 & 3.

The polyester resin composites for the aforementioned applications also can be prepared with a single screw extruder, twin screw extruder, monoaxial extruder, biaxial extruder, kneader or like apparatuses.

The invention is not limited only for injection molding process but can also be processed by compression molding, blow molding, thermoforming, and plastic part related manufacturing process to produce the useful components.

ADVANTAGES OF THE PRESENT INVENTION:

1) Polyester resin used for this application is obtained from environmentally progressive source like consumer used waste recycled PET.
2) PET wastes causes pollution to environments in many ways, sometimes the PET wastes are burned that could release the CO2 and pollute the air. PET will not degrade as itself in earth, so accumulation these kind of plastics on earth in long term will affect the recirculation of rain water to the underwater system. So by using the recycled PET resin for engine cover application can reduce the above mentioned environment pollutions as well as it will avoid the consumption of crude oil based virgin PET resin, which also will reduce the consumption of oils and release of CO2 while manufacturing.
3) Cost reduction is achieved as compared to the conventional polyamide engine covers.

WE CLAIM:

1. Injection molded automotive component made from polyester composites, comprising of at least a polyester, glass filler, epoxy additive, antistatic agents, thermal stabilizers, process stabilizers and antioxidant additives;
wherein polyester composite comprises combination at least two different IV of polyesters, preferably recycled poly ethylene terephthalate (RPET) resin 55-92% by weight and the RPET resin having the IV range from 0.1 - 1.5; wherein these two IVs are from two different consumer used sources, one IV is from PET bottles and another IV is from non bottle source like PET films and fibers;
wherein most optimized range of glass filler (silica fibers) is 22 - 36 % by weight;
wherein epoxy additive of low molecular weight (100 to 3000 gram/mole) is 0.05 to 3% by weight;
wherein antistatic agents are from metal alkyl sulphonate derivatives and is 0.02 to 5% by weight;
wherein process stabilizer is 0.05 to 1% by weight of stearate based additive.

2. Injection molded automotive component made from polyester composites as claimed in 1, wherein poly ethylene terephthalate (PET) resins are obtained from different consumer used product sources like PET bottles, films and fibers.

3. Injection molded automotive component made from polyester composites as claimed in 1, wherein polyester composites is prepared by combining RPET with different polymeric resins obtained from bio-derived, petroleum derived, consumer and industrial waste recycled sources;
wherein polymeric resins is olefins, amides, esters, carbonates, imdies, ethers, styrenes, dienes, and acrylics;
wherein resin chain architect is graft, oligomer, elastomers, rubber, reactive, crosslinkable, curing polymers dendrimers, ionomers, core shell polymer, monomer, copolymer, ter polymer, star or nano polymer related types.

4. Injection molded automotive component made from polyester composites as claimed in 1, wherein fillers like talc, mica, nano fillers or its combination can also be preferred.

5. Injection molded automotive component made from polyester composites as claimed above, wherein the component is vibration resistant at higher frequency of 73 Hz.

6. Injection molded automotive component made from polyester composites as claimed above, wherein the component has high ductility, impact, stiffness, thermal resistance and long term heat ageing resistance (as mentioned in Table 1).