CLIAMS:1. A polyester composition comprising:
a. at least one polyester component, in an amount ranging between 90% and 99.5% of the total mass of the composition;
b. at least one polyester modifier, selected from the group consisting of co-monomers and viscosity reducing agents, in an amount ranging between 0.1 % and 10% of the total mass of the composition; and
c. at least one nucleating agent in an amount ranging between 10 ppm and 1000 ppm w.r.t the total mass of the composition.
2. The composition as claimed in claim 1, having viscosity ranging between 20 and 80 Pa.S at a shear rate ranging between 800 and 12,000 sec-1.
3. The composition as claimed in claim 1, further comprises at least one additive selected from the group consisting of catalysts, stabilizers and colorants.
4. The composition as claimed in claim 1, wherein said polyester component is at least one selected from the group consisting of homopolyester and copolyester.
5. The composition as claimed in claim 1, wherein said polyester component is obtained by polymerizing at least one compound selected from the group of aromatic dicarboxylic acids consisting of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, naphthalene dicarboxylic acid and cyclohexane dicarboxylic acid or the corresponding diester and at least one compound selected from the group of aliphatic diols consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexane diol, 8-octane diol, 1,10 decanediol, 1,4-cyclohexane dimethanol, 1,4-cyclohexane diol, cyclobutanediol, cyclobutane dimethanol, tetramethane cyclobutanediol and their ester forming derivatives.
6. The composition as claimed in claim 1, wherein said co-monomer is at least one diol co-monomer selected from the group consisting of 2-methylpropane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol.
7. The composition as claimed in claim 1, wherein said viscosity reducing agent is at least one selected from the group consisting of stearic acid, Groups 1, 2, 12, and 13 metal salts of stearic acid, stearic acid amides, stearic acid esters, polybutylene, polymethacrylates, waxes, polyethylene glycol (PEG), polypropylene glycol (PPG), alkoxyl terminated PEG, polyethylene oxide (PEO), polypropylene oxide (PPO) and polyethylene waxes.
8. The composition as claimed in claim 1, wherein said nucleating agent is at least one selected from the group consisting of sodium benzoate, aluminum benzoate, aluminum p-tert-butyl benzoate, di(4-tert-butylphenyl) phosphate, polyvinyl cyclohexane, talc, AR talc, oxalic acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid and malonic acid.
9. A thin walled packaging article prepared from the composition as claimed in claim 1; said article being selected from the group consisting of bottles, films, crates, boxes, pails, cups, cans, sachets, bowls, lids, containers, bags, pouches, wrappers, jars and canisters, having wall thickness ranging from 300 to 500 microns.
10. A process for the preparation of a polyester composition; said process comprising:
i. esterifying at least one aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, naphthalene dicarboxylic acid and cyclohexane dicarboxylic acid or the corresponding diester with at least one aliphatic diol selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexane diol, 8-octane diol, 1,10 decanediol, 1,4-cyclohexane dimethanol, 1,4-cyclohexane diol, cyclobutanediol, cyclobutane dimethanol, tetramethane cyclobutanediol and their ester forming derivatives, at a temperature ranging between 220 and 300 oC to obtain an esterified product;
ii. incorporating at least one polyester modifier selected from the group consisting of co-monomers and viscosity reducing agents and at least one nucleating agent before, during or after said step of esterification, wherein said co-monomer is at least one diol co-monomer selected from the group consisting of 2-methylpropane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol; said viscosity reducing agent is at least one selected from the group consisting of stearic acid, Groups 1, 2, 12, and 13 metal salts of stearic acid, stearic acid amides, stearic acid esters, polybutylene, polymethacrylates, waxes, polyethylene glycol (PEG), polypropylene glycol (PPG), alkoxyl terminated PEG, polyethylene oxide (PEO), polypropylene oxide (PPO) and polyethylene waxes and said nucleating agent is at least one selected from the group consisting of sodium benzoate, aluminum benzoate, aluminum p-tert-butyl benzoate, di(4-tert-butylphenyl) phosphate, polyvinyl cyclohexane, talc, AR talc, oxalic acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid and malonic acid; and
iii. melt polymerizing said esterified product at a temperature ranging between 250 and 310 oC in the presence of at least one catalyst, optionally at least one colorant and optionally at least one stabilizer to obtain the polyester resin composition.
11. A process for the preparation of a thin walled packaging article prepared from a polyester composition; said process comprising the following steps:
i. esterifying at least one aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, naphthalene dicarboxylic acid and cyclohexane dicarboxylic acid or the corresponding diester with at least one aliphatic diol selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexane diol, 8-octane diol, 1,10 decanediol, 1,4-cyclohexane dimethanol, 1,4-cyclohexane diol, cyclobutanediol, cyclobutane dimethanol, tetramethane cyclobutanediol and their ester forming derivatives, at a temperature ranging between 220 and 300 oC to obtain an esterified product;
ii. incorporating at least one polyester modifier selected from the group consisting of co-monomers and viscosity reducing agents and at least one nucleating agent before, during or after said step of esterification, wherein said co-monomer is at least one diol co-monomer selected from the group consisting of 2-methylpropane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol; said viscosity reducing agent is at least one selected from the group consisting of stearic acid, Groups 1, 2, 12, and 13 metal salts of stearic acid, stearic acid amides, stearic acid esters, polybutylene, polymethacrylates, waxes, polyethylene glycol (PEG), polypropylene glycol (PPG), alkoxyl terminated PEG, polyethylene oxide (PEO), polypropylene oxide (PPO) and polyethylene waxes and said nucleating agent is at least one selected from the group consisting of sodium benzoate, aluminum benzoate, aluminum p-tert-butyl benzoate, di(4-tert-butylphenyl) phosphate, polyvinyl cyclohexane, talc, AR talc, oxalic acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid and malonic acid;
iii. melt polymerizing said esterified product at a temperature ranging between 250 and 310 oC in the presence of at least one catalyst, optionally at least one colorant and optionally at least one stabilizer to obtain the polyester resin composition; and
iv. subjecting said polyester resin composition to molding to obtain the thin walled packaging article, having wall thickness ranging from 300 to 500 microns. ,TagSPECI:FIELD OF THE DISCLOSURE
The present disclosure relates to a polyester resin composition. More particularly, the present disclosure relates to a polyester resin composition for the preparation of thin walled injection molded packaging articles.

BACKGROUND
Packaging materials for substances such as food, beverages and cosmetics; and the packaging articles prepared therefrom, have evolved extensively over time, owing to the ever increasing demand for aesthetic and user-friendly packaging articles by the customers, seconded by the fierce competition amongst manufacturers.
Plastics have surpassed conventional packaging materials such as glass, metal and paper due to their overtly superior properties such as light weight, inertness, comparative ease of moldability, transparency, gloss and shatter resistance. Compression molding, extrusion molding, transfer molding, blow molding and injection molding are the different types of methods for manufacturing packaging articles, especially containers from plastic.
Thin wall injection molding is a recent advancement in the art wherein specialized modifications are made to the mold, machinery and part design to provide thin walled articles. Polypropylene has been popularly used for preparing thin walled containers. However, it is accompanied by certain disadvantages such as high thermal expansion, poor weathering resistance, UV degradation and flammability. Conventional polyester resin has also been used for manufacturing thin wall injection molding applications, however, its high viscosity during downstream processing and faster crystallization rate leads to clogging of the machine parts; thereby adversely affecting the speed and efficiency.
US 6727306 discloses a polymer resin that includes 20 to 200 ppm of surface modified talc or calcium carbonate as an inert additive to prepare plastic bottles and films. US 7354653 discloses the preparation of a calendered film from a polyester composition comprising an aliphatic aromatic polyetser and a release additive. The release additive of US 7354653 includes stearic acid, montanic acid, palmitic acid, paraffin wax and the like. The practice of inclusion of certain additives in the polyester has, thus, been developed. Likewise, US 4161579 discloses the use of modified polyethylene terephthalate for preparing plastic containers, whereby chain branching agents such as pentaerythritol and chain terminating agents such as stearic acid are used as the modifiers. The modified polyethylene terephthalate is however, converted to plastic containers by the process of extrusion blow molding. US 20060217495 discloses a polyester resin composition comprising an amorphous polyester, a crystalline polyester or a nucleating agent such as talc and a reactive compound for the preparation of plastic containers. The composition of US 20060217495 is also, however, processed by the profile extrusion molding technique.
Most of the conventional techniques therefore suffer from drawbacks such as requirement of high capital cost. Thin wall injection molding, on the contrary is an extremely cost effective technique as the raw material wastage is significantly less. Furthermore, the cycle times are also shorter due to thinner parts.
Therefore, there exists a need to develop an effective via media to render the conventional polyester suitable for processing using the thin wall molding technique.

OBJECTS
Some of the objects of the present disclosure, which at least one embodiment is able to achieve, are discussed herein below.
It is an object of the present disclosure to provide a polyester composition.
It is another object of the present disclosure to provide a process for the preparation of the polyester composition.
It is still another object of the present disclosure to provide a polyester composition for the preparation of thin walled containers.
It is yet another object of the present disclosure to provide a process for the preparation of thin walled containers from the polyester composition.
It is still another object of the present disclosure to provide a cost and time effective process for the preparation of thin walled containers from the polyester composition.
It is yet another object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
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 provides a polyester composition comprising:
a. at least one polyester component, in an amount ranging between 90% and 99.5% of the total mass of the composition;
b. at least one polyester modifier, selected from the group consisting of co-monomers and viscosity reducing agents, in an amount ranging between 0.1 % and 10% of the total mass of the composition; and
c. at least one nucleating agent in an amount ranging between 10 ppm and 1000 ppm w.r.t the total mass of the composition.
Typically, the composition has viscosity ranging between 20 and 80 Pa.S at a shear rate ranging between 800 and 12,000 sec-1.
Typically, the composition further comprises at least one additive selected from the group consisting of catalysts, stabilizers and colorants.
Typically, the polyester component is at least one selected from the group consisting of homopolyester and copolyester.
Typically, the polyester component is obtained by polymerizing at least one compound selected from the group of aromatic dicarboxylic acids consisting of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, naphthalene dicarboxylic acid and cyclohexane dicarboxylic acid or the corresponding diester and at least one compound selected from the group of aliphatic diols consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexane diol, 8-octane diol, 1,10 decanediol, 1,4-cyclohexane dimethanol, 1,4-cyclohexane diol, cyclobutanediol, cyclobutane dimethanol, tetramethane cyclobutanediol and their ester forming derivatives.
Typically, the co-monomer is at least one diol co-monomer selected from the group consisting of 2-methylpropane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol.
Typically, the viscosity reducing agent is at least one selected from the group consisting of stearic acid, Groups 1, 2, 12, and 13 metal salts of stearic acid, stearic acid amides, stearic acid esters, polybutylene, polymethacrylates, waxes, polyethylene glycol (PEG), polypropylene glycol (PPG), alkoxyl terminated PEG, polyethylene oxide (PEO), polypropylene oxide (PPO) and polyethylene waxes.
Typically, the nucleating agent is at least one selected from the group consisting of sodium benzoate, aluminum benzoate, aluminum p-tert-butyl benzoate, di(4-tert-butylphenyl) phosphate, polyvinyl cyclohexane, talc, AR talc, oxalic acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid and malonic acid.
The present disclosure further provides a thin walled packaging article prepared from the afore-stated composition; said article being selected from the group consisting of bottles, films, crates, boxes, pails, cups, cans, sachets, bowls, lids, containers, bags, pouches, wrappers, jars and canisters, having wall thickness ranging from 300 to 500 microns.
The present disclosure still further provides a process for the preparation of a polyester composition; said process comprising:
i. esterifying at least one aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, naphthalene dicarboxylic acid and cyclohexane dicarboxylic acid or the corresponding diester with at least one aliphatic diol selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexane diol, 8-octane diol, 1,10 decanediol, 1,4-cyclohexane dimethanol, 1,4-cyclohexane diol, cyclobutanediol, cyclobutane dimethanol, tetramethane cyclobutanediol and their ester forming derivatives, at a temperature ranging between 220 and 300 oC to obtain an esterified product;
ii. incorporating at least one polyester modifier selected from the group consisting of co-monomers and viscosity reducing agents and at least one nucleating agent before, during or after said step of esterification, wherein said co-monomer is at least one diol co-monomer selected from the group consisting of 2-methylpropane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol; said viscosity reducing agent is at least one selected from the group consisting of stearic acid, Groups 1, 2, 12, and 13 metal salts of stearic acid, stearic acid amides, stearic acid esters, polybutylene, polymethacrylates, waxes, polyethylene glycol (PEG), polypropylene glycol (PPG), alkoxyl terminated PEG, polyethylene oxide (PEO), polypropylene oxide (PPO) and polyethylene waxes and said nucleating agent is at least one selected from the group consisting of sodium benzoate, aluminum benzoate, aluminum p-tert-butyl benzoate, di(4-tert-butylphenyl) phosphate, polyvinyl cyclohexane, talc, AR talc, oxalic acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid and malonic acid; and
iii. melt polymerizing said esterified product at a temperature ranging between 250 and 310 oC in the presence of at least one catalyst, optionally at least one colorant and optionally at least one stabilizer to obtain the polyester resin composition.
The present disclosure even further provides a process for the preparation of a thin walled packaging article prepared from a polyester composition; said process comprising the following steps:
i. esterifying at least one aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, naphthalene dicarboxylic acid and cyclohexane dicarboxylic acid or the corresponding diester with at least one aliphatic diol selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexane diol, 8-octane diol, 1,10 decanediol, 1,4-cyclohexane dimethanol, 1,4-cyclohexane diol, cyclobutanediol, cyclobutane dimethanol, tetramethane cyclobutanediol and their ester forming derivatives, at a temperature ranging between 220 and 300 oC to obtain an esterified product;
ii. incorporating at least one polyester modifier selected from the group consisting of co-monomers and viscosity reducing agents and at least one nucleating agent before, during or after said step of esterification, wherein said co-monomer is at least one diol co-monomer selected from the group consisting of 2-methylpropane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol; said viscosity reducing agent is at least one selected from the group consisting of stearic acid, Groups 1, 2, 12, and 13 metal salts of stearic acid, stearic acid amides, stearic acid esters, polybutylene, polymethacrylates, waxes, polyethylene glycol (PEG), polypropylene glycol (PPG), alkoxyl terminated PEG, polyethylene oxide (PEO), polypropylene oxide (PPO) and polyethylene waxes and said nucleating agent is at least one selected from the group consisting of sodium benzoate, aluminum benzoate, aluminum p-tert-butyl benzoate, di(4-tert-butylphenyl) phosphate, polyvinyl cyclohexane, talc, AR talc, oxalic acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid and malonic acid;
iii. melt polymerizing said esterified product at a temperature ranging between 250 and 310 oC in the presence of at least one catalyst, optionally at least one colorant and optionally at least one stabilizer to obtain the polyester resin composition; and
iv. subjecting said polyester resin composition to molding to obtain the thin walled packaging article, having wall thickness ranging from 300 to 500 microns.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The disclosure will now be described with reference to the accompanying non-limiting drawing:
Figure 1 illustrates the effect of shear rate on the viscosity of the composition of the present disclosure.

DETAILED DESCRIPTION
The practice of using thin walled containers as packaging material for food, beverage and cosmetics is on the rise, chiefly due to advantages such as improved economy and short cycle times. The inventors of the present disclosure, therefore, provide a polyester composition that can be effectively processed by thin wall injection molding technique.
The composition of the present disclosure includes ingredients such as at least one polyester component, at least one polyester modifier, at least one nucleating agent and optionally, at least one additive that aid in regulating the physical properties of the composition; thereby avoiding the impending problems associated with the downstream processing of conventional polyester. Typically, the viscosity of the composition of the present disclosure ranges between 20 and 80 Pa.S at 800 sec-1 and 12000 sec-1 shear rate so that the viscosity of the composition is almost 40-60% lower as compared to the conventional PET recipe.
The polyester component of the present disclosure forms the base and is present in an amount ranging between 90% and 90.5% of the total mass of the composition. In one embodiment, the composition is a homopolyester. In another embodiment, the composition is a copolyester. The polyester component of the present disclosure is obtained by polymerizing at least one compound selected from the group of aromatic dicarboxylic acids that includes but is not limited to terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, naphthalene dicarboxylic acid and cyclohexane dicarboxylic acid or the corresponding diester and at least one compound selected from the group of aliphatic diols that includes but is not limited to ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexane diol, 8-octane diol, 1,10 decanediol, 1,4-cyclohexane dimethanol, 1,4-cyclohexane diol, cyclobutanediol, cyclobutane dimethanol, tetramethane cyclobutanediol and their ester forming derivatives.
The composition of the present disclosure includes at least one co-monomer and at least one viscosity reducing agent as the polyester modifier. The co-monomer of the present disclosure is present in an amount ranging between 0.0.5 wt % and 10 wt %. The co-monomer, in one embodiment, is a diol co-monomer. The diol co-monomer is selected from the group that includes but is not limited to 2-methylpropane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol. The diol co-monomer because of its bulky structure provides flexibility and also reduces the melting temperature and crystallization rate during cooling from the melt in injection molding process thus imparting better clarity and gloss.
Conventional polyester generally has a high viscosity and therefore, may pose significant problems during downstream processing. The composition of the present disclosure, therefore, includes at least one viscosity reducing agent as one of the polyester modifiers to solve this problem. The viscosity reducing agent is at least one selected from the group that includes but is not limited to stearic acid, Groups 1, 2, 12, and 13 metal salts of stearic acid, stearic acid amides, stearic acid esters, polybutylene, polymethacrylates, waxes, polyethylene glycol (PEG), polypropylene glycol (PPG), alkoxyl terminated PEG, polyethylene oxide (PEO), polypropylene oxide (PPO) and polyethylene waxes. Further, the viscosity reducing agent is present in an amount ranging between 0.1 wt % and 5 wt %.
Similarly, the present disclosure describes inclusion of at least one nucleating agent in the polyester resin composition for increasing the polymer crystallization temperature, which leads to shorter processing cycles; thereby saving energy. The nucleating agent is at least one selected from the group that includes but is not limited to sodium benzoate, aluminum benzoate, aluminum p-tert-butyl benzoate, di(4-tert-butylphenyl) phosphate, polyvinyl cyclohexane, talc, AR talc, oxalic acid, 1,2-cyclohexanedicarboxylic acid, phthalic acid and malonic acid and is present in an amount ranging between 10 ppm and 1000 ppm w.r.t the total mass of the composition. In one embodiment, the nucleating agent is AR Talc.
The present disclosure further includes at least one additive selected from the group consisting of catalysts, stabilizers and colorants. The catalyst is at least one selected from the group consisting of salts or oxides of tin and antimony, in order to catalyze the steps of esterification and polymerization involved in preparing the polyester component. Further, the stabilizer is phosphorus and the colorant is cobalt.
The present disclosure further provides a process for the preparation of the afore-stated polyester composition. The process includes esterifying at least one aromatic dicarboxylic acid with at least one aliphatic diol, optionally, in the presence of at least one catalyst at a temperature ranging between 220 and 300 oC to obtain an esterified product. In one embodiment, the proportion of the aromatic dicarboxylic acid to the aliphatic diol is taken as 1: 2. In order to improve the flow properties and therefore the process speed and efficiency, at least one polyester modifier is added before, during or after the esterification step.
Further, the esterified product is subjected to melt polymerization at a temperature ranging between 250 and 310 oC in the presence of at least one catalyst to obtain the polyester resin composition. Additives such as at least one colorant and at least one stabilizer may also be optionally incorporated in the step of esterification.

The composition provided by the present disclosure is processed in a thin wall injection molding assembly to provide thin walled packaging articles having wall thickness ranging from 200 to 500 microns. The thin walled packaging articles of the present disclosure are selected from the group that includes but is not limited to bottles, films, crates, boxes, pails, cups, cans, sachets, bowls, lids, containers, bags, pouches, wrappers, jars and canisters. In one embodiment, the thin walled packaging articles of the present disclosure are used for packaging food products and beverages.
The present disclosure even further provides a process for the preparation of the thin walled packaging article from the polyester resin composition. The process initially includes preparing the polyester resin composition of the present disclosure as stated herein above. The polyester resin composition is then subjected to molding to obtain the thin walled packaging article. Typically, the article has wall thickness ranging from 200 to 500 microns. The article prepared from the process of the present disclosure has a better glossy appeal and clarity due to the ingredients included along with conventional polyester. Further, there is minimum wastage of ingredients as the thin wall molding technique is used. Still further, due to a decrease in the viscosity of the composition, problems of clogging of the injection port do not arise; thereby saving both time and money.
The present disclosure will now be discussed in the light of the following non-limiting embodiments:
Example 1: Preparation of the polyester composition of the present disclosure (Control)
Purified terephthalic acid was esterified with MEG in 1:2 ratio along with 1.8 wt % Isophthalic acid (IPA) at 260 °C and Tin oxalate (35 ppm as a metallic tin) in the form of slurry at 260 °C. The oligomer obtained was further melt polymerized at 290 °C to obtain amorphous polyester polymer having IV up to 0.6 dl/g. About 290 ppm of antimony was added as a catalyst, 25 ppm P and cobalt were added as a thermal stabilizer and colorant to the oligomer. The low IV polymer melt was then extruded out from the reactor in the form of amorphous cylindrical chips. This polymer was considered as “Control”. These amorphous chips were analyzed for IV, Color and COOH content. These amorphous polymer particles were crystallized in the crystallizer at 150 °C temperature and dried at 160 °C for 4 hours and used directly for thin walled injection molding.

Example 2: Preparation of the polyester composition of the present disclosure (with co-monomer and nucleating agent)
Purified terephthalic acid was esterified with monoethylene glycol (MEG) in 1:2 ratio along with 3 wt % 2-methyl propane diol as a co-monomer, 100 ppm AR Talc as an nucleating agent, and Tin oxalate (35 ppm as a metallic tin) in the form of slurry at 260 °C . The oligomer obtained was further melt polymerized at 290 °C to obtain polyester polymer having IV up to 0.6 dl/g. About 290 ppm of antimony was added as a catalyst and 25 ppm P and Cobalt were added as a thermal stabilizer and colorant to the oligomer. The low IV polymer melt was then extruded out from the reactor in the form of amorphous cylindrical chips. These amorphous chips were analyzed for IV, Color and COOH content. These amorphous polymer particles were crystallized in the crystallizer at 150 °C temperature and dried at 160 °C for 4 hours and used directly for thin walled injection molding.

Example 3: Preparation of the polyester composition of the present disclosure (with co-monomer, nucleating agent and viscosity reducing agent)
Purified terephthalic acid was esterified with monoethylene glycol (MEG) in 1:2 ratio along with 3 wt % 2-methyl propane diol, 1% Stearic acid as viscosity reducer and 100 ppm AR Talc as an nucleating agent, and Tin oxalate (35 ppm as a metallic tin) in the form of slurry at 260 °C. The oligomer obtained was further melt polymerized at 290 °C to obtain polyester polymer having IV up to 0.6 dl/g. About 290 ppm of antimony was added as a catalyst and 25 ppm P and Cobalt were added as a thermal stabilizer and colorant to the oligomer. The low IV polymer melt was then extruded out from the reactor in the form of amorphous cylindrical chips. These amorphous chips were analyzed for IV, Color and COOH content. These amorphous polymer particles were crystallized in the crystallizer at 150 °C temperature and dried at 160 °C for 4 hours and used directly for thin walled injection molding.
Table 1. Composition of the Examples 1, 2 and 3 - Effect on esterification time and polycondensation time
Example No. IPA
(%) Co-monomer
(%) Stearic Acid
(%) Nucleating agent
(ppm) Esterification Time (Min) Polycondensation Time (Min)
1 1.8 Nil Nil Nil 203 114
2 Nil 3 Nil 100 218 163
3 Nil 3 1 100 240 164

Table 2. Comparison of the amorphous chips prepared in Examples 1, 2 and 3
Example No. Intrinsic Viscosity
IV(dl/g) Lab color space analysis COOH content (meq/Kg) AA(ppm)
L* a* b*
1 0.615 69.3 0.62 -1.54 28 33
2 0.609 68.9 0.88 -2.8 33 25
3 0.604 68.6 -0.59 2.8 34 32

From Table 2, it can be concluded that the intrinsic viscosity of the composition containing a co-monomer, a nucleating agent and a viscosity reducing agent along with the polyester component, reduces the intrinsic viscosity of the composition which aids in preventing clogging of the machine parts. This improves the speed and efficiency in preparing thin walled packaging articles. Furthermore, the results of the Esterification time test and Polycondensation time test demonstrate that addition of a co-monomer, a nucleating agent and a viscosity reducing agent do not adversely affect the reaction time. Still further, the results represented in Table 2 indicate that parameters such as appearance and acetaldehyde content of the composition of the present disclosure are comparable with that of the control.
Viscosity Measurement
The amorphous pre-polymer particles obtained in Examples 1, 2 and 3 were crystallized in a crystallizer at 150 °C temperature and dried at 160 °C for 4 hours and used directly for rheological experiments. The results obtained are
Table 3. Viscosity of pre-polymer particles prepared in Examples 1, 2 and 3
Temperature 270 oC
Example No. 1 2 3
Shear Rate (sec-1) Viscosity (Pa*s)
1000
2500
5000
7500
10000 159 73 59
118 67 54
86 51 45
70 48 38
59 42 33

The results obtained have also been represented in Figure 1. It is evident that the viscosity of the control composition is initially high which decreases exponentially upon an increase in the shear rate. The viscosity of the composition of the present disclosure is always less than that of the control and is not affected by change in shear rate as much as the control.
Example 4: Preparation of a thin walled article from the polyester resin composition of the present disclosure
The polyester composition obtained in Example 3 was subjected to molding at 230 to 260 oC to obtain a molded article in the form of a container (tub) having 400 microns as the thickness.
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.

The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention and the claims unless there is a statement in the specification to the contrary.

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 in the process or compound or formulation or combination 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 accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.

TECHNICAL ADVANCEMENT AND ECONOMIC SIGNIFICANCE
The present process for the preparation of the thin walled article is economical and consumes less time.
Further, the articles prepared by using the composition of the present disclosure have improved clarity and gloss as compared to the articles prepared from conventional polyethylene terephthalate (PET) compositions.