Claims:1. A process for improving polymerization rate of polyester comprising reacting polyester with a composition comprising a resin carrier and a branching agent.

2. The process as claimed in claim 1, wherein the polyester is selected from a group comprising polyethylene terephthalate, poly trimethylene terephthalate, poly ethylene naphthalate and combinations thereof.

3. The process as claimed in claim 1, wherein the polyethylene terephthalate is virgin polyethylene terephthalate or recycled polyethylene terephthalate and their combination.

4. The process as claimed in claim 1, wherein the process is carried out in solid-state or liquid state and combinations thereof.

5. A process for improving solid-state polymerization rate of polyethylene terephthalate comprising reacting polyethylene terephthalate with a masterbatch composition comprising a resin carrier and a branching agent.

6. A process for improving solid-state polymerization rate of polyethylene terephthalate comprising
- melt blending a masterbatch composition comprising a resin carrier and a branching agent with polyethylene terephthalate to obtain a melt blended chips of modified polyethylene terephthalate;
- subjecting the melt-blended chips of polyethylene terephthalate to solid-state polymerization to obtain a polyethylene terephthalate with altered intrinsic viscosity.

7. The process as claimed in any of the preceding claims, wherein the branching agent is selected from a group comprising pentaerythritol, trimellitic anhydride, pyromellitic anhydride, tetraglycidyl diamino diphenyl methane, Phenylene bisoxazoline and combinations thereof.

8. The process as claimed in any of the preceding claims, wherein the resin carrier is polybutylene terephthalate, poly trimethylene terephthalate, poly ethylene naphthalate, polycarbonate and combinations thereof.

9. The process as claimed in any of the preceding claims, wherein the concentration of branching agent in the master batch composition ranges from about 0.5 wt% to 30wt%.

10. The process as claimed in any of the preceding claims, wherein melt blending of a masterbatch composition comprising a resin carrier and a branching agent with polyethylene terephthalate is carried out during extrusion process.

11. The process as claimed in any of the preceding claims, wherein said process is carried out at a temperature ranging from about 180 ? to 230 ?, preferably about between 200 - 220 ?.

12. The process as claimed in any of the preceding claims, wherein said process is carried out for a time period ranging from about 2 hours to 20 hours, preferably about 4-8 hours.

13. The process as claimed in any of the preceding claims, wherein said process is carried out under inert gas atmosphere or under vacuum.

14. The process as claimed in claim 12, wherein the inert gas atmosphere is nitrogen gas atmosphere.

15. The process as claimed in claim 1, wherein the composition comprising a resin carrier and a branching agent is prepared in Twin screw extruder equipment by melt mixing 10% pentaerythritol & 90% PBT at 220 – 260°C.

16. The process as claimed in any of the preceding claims, wherein the polyethylene terephthalate with altered intrinsic viscosity is isolated and optionally purified; and wherein said isolation and purification is carried out by acts selected from a group consisting of solvent extraction or precipitation of the product, filtration, drying, and combinations thereof, preferably a combination of precipitation using alcohol, filtration and drying.

17. The process as claimed in any of the preceding claims, wherein said altered intrinsic viscosity includes the increase in the intrinsic viscosity of polymers with a flow in the range of about 0.7 to 1.2 dl/g.

18. A masterbatch composition comprising a resin carrier and a branching agent.

Dated this 28th day of March 2019
Signature:
Name: Durgesh Mukharya
To: Of K&S Partners, Bangalore
The Controller of Patents Agent for the Applicant
The Patent Office, at Mumbai
, Description:TECHNICAL FIELD
[001]. The instant disclosure is in the field of chemical sciences, more particularly to synthetic chemistry and polymer science. The present disclosure relates to a method for improving solid-state polymerization rate of polyester. In an exemplary embodiment, the disclosure relates to a method of improvement in solid-state polymerization rate of polyethylene terephthalate with a composition comprising a resin carrier and a branching agent.

BACKGROUND OF THE DISCLOSURE
[002]. Polyethylene terephthalate (PETE or PET) is the widely used thermoplastic polymer used for manufacturing shaped articles which may be used as a fiber for clothing, as an effective moisture barrier with wide applicability in bottling and packaging due to their superior physico chemical properties. However, PET is less suitable for fabrication of beverage containers, films, sheet, straps, and industrial yarn production as the intrinsic viscosity of these polymers is not adequate to use in the said applications.
[003]. Therefore, there is a need to modify polyethylene terephthalate to improve intrinsic viscosity and improved properties of the polyester materials. The present disclosure tried to address said need.

SUMMARY OF THE DISCLOSURE
[004]. The present disclosure relates to a process for improving polymerization rate of polyester comprising reacting polyester with a composition comprising a resin carrier and a branching agent.
[005]. In an embodiment, the disclosure relates to a process for improving solid-state polymerization rate of polyethylene terephthalate comprising reacting polyethylene terephthalate with a masterbatch composition comprising a resin carrier and a branching agent.
[006]. In another embodiment, the present process for improving solid-state polymerization rate of polyethylene terephthalate comprising
- melt blending a masterbatch composition comprising a resin carrier and a branching agent with polyethylene terephthalate to obtain a melt blended chips of modified polyethylene terephthalate;
- subjecting the melt-blended chips of polyethylene terephthalate to solid-state polymerization to obtain a polyethylene terephthalate with altered intrinsic viscosity.
[007]. In yet another embodiment, the present process for improving solid-state polymerization rate of polyethylene terephthalate is carried out at a temperature ranging from about 195? to 225 ?.
[008]. In still another embodiment, the present process for improving solid-state polymerization rate of polyethylene terephthalate is carried out for a time period ranging from about 6 hours to16 hours.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
[009]. In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, where:

[0010]. Figure 1 depicts pictorial representation of the present process/set-up for improving solid-state polymerization rate of polyethylene terephthalate.

STATMENT OF THE DISCLOSURE
[0011]. The present disclosure relates to a process for the present process for improving solid-state polymerization rate of polyethylene terephthalate comprising
- melt blending a masterbatch composition comprising a resin carrier and a branching agent with polyethylene terephthalate to obtain a melt blended chips of modified polyethylene terephthalate;
- subjecting the melt-blended chips of polyethylene terephthalate to solid-state polymerization to obtain a polyethylene terephthalate with altered intrinsic viscosity.

DESCRIPTION OF THE DISCLOSURE
[0001] A detailed description for the purpose of illustrating representative embodiments of the present invention is given below, but these embodiments should not be construed as limiting the present invention.
[0002] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. The use of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.80, 3, 3.75, 4, and 5) and any range within that range.
[0012]. As used herein, the term "masterbatch" has the common meaning as would be understood by one skilled in the art. With particular reference to the present invention, a masterbatch is a composition comprising a resin carrier and a branching agent.
[0013]. As used herein, the term "branching agent" or "branching compound" is used to denote a multifunctional compound which can react with a polyester to introduce branching therein.
[0014]. As used herein, the terms/phrases ‘polyethylene terephthalate’, ‘PETE’, and ‘PET’ are employed interchangeably in the present disclosure.
[0015]. As used herein, the terms/phrases ‘carrier resin’, ‘polybutylene terephthalate’, and ‘PBT’ are employed interchangeably in the present disclosure.
[0016]. In the present disclosure, a process is provided for improving polymerization rate of polyester comprising reacting polyester with a composition comprising a resin carrier and a branching agent. In particular, in order to address the limitations as stated in the background, the present disclosure provides a simple and efficient process for improving polymerization rate of polyester.
[0017]. In an embodiment of the present disclosure, the polyester is selected from a group comprising polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and combinations thereof.
[0018]. In another embodiment of the present disclosure, the polyethylene terephthalate is virgin polyethylene terephthalate (PET) or recycled polyethylene terephthalate (rPET) and their combination.
[0019]. In an embodiment of the present disclosure, the process is carried out in solid-state or liquid state and combinations thereof
[0020]. The present disclosure further provides a process for improving solid-state polymerization rate of polyethylene terephthalate comprising reacting polyethylene terephthalate with a masterbatch composition comprising a resin carrier and a branching agent.
[0021]. The present disclosure also provides a process for improving solid-state polymerization rate of polyethylene terephthalate comprising
- melt blending a masterbatch composition comprising a resin carrier and a branching agent with polyethylene terephthalate to obtain a melt blended chips of modified polyethylene terephthalate; and
- subjecting the melt-blended chips of polyethylene terephthalate to solid-state polymerization to obtain a polyethylene terephthalate with altered intrinsic viscosity.
[0022]. In an embodiment of the present disclosure, the branching agent is selected from a group comprising pentaerythritol, trimellitic anhydride, pyromellitic anhydride, tetraglycidyl diamino diphenyl methane, Phenylene bisoxazoline and combinations thereof.
[0023]. In another embodiment of the present disclosure, the concentration of branching agent in the master batch composition ranges from about 10 wt% to 20wt%.
[0024]. In an embodiment of the present disclosure, the resin carrier is polybutylene terephthalate, polyethylene terepthalate, poly trimethylene terephthalate, poly ethylene naphthalate and combinations thereof.
[0025]. In still another embodiment of the present disclosure, the melt blending of a masterbatch composition comprising a resin carrier and a branching agent with polyethylene terephthalate is carried out during extrusion process. In particular, the master-batch is mixed with virgin or recycled PET using twin screw extrusion process.
[0026]. In another embodiment of the present disclosure, the process is carried out under nitrogen gas atmosphere.
[0027]. In another embodiment of the present disclosure, the process is carried out at a temperature ranging from about 195 ? to 225 ?, preferably about 215 ?.
[0028]. In yet another embodiment of the present disclosure, the process is carried out for a time period ranging from about 6 hours to 16 hours, preferably about 6 hours.
[0029]. In still another embodiment of the present disclosure, the process is carried out under nitrogen gas atmosphere.
[0030]. In yet another embodiment of the present disclosure, the polyethylene terephthalate with altered intrinsic viscosity is isolated and optionally purified; and wherein said isolation and purification is carried out by acts selected from a group consisting of solvent extraction or precipitation of the product, filtration, drying, and combinations thereof, preferably a combination of precipitation using alcohol, filtration and drying.
[0031]. The present disclosure further provides composition comprising a resin carrier and a branching agent.
[0032]. In an embodiment of the present disclosure, the composition is a masterbatch composition.
[0033]. In an embodiment of the present disclosure, the branching agent is selected from a group comprising pentaerythritol, trimellitic anhydride, pyromellitic anhydride, tetraglycidyl diamino diphenyl methane, Phenylene bisoxazoline and combinations thereof.
[0034]. In another embodiment of the present disclosure, the concentration of branching agent in the master batch composition ranges from about 10 wt% to 20wt%.
[0035]. In an embodiment of the present disclosure, the resin carrier is polybutylene terephthalate, polyethylene terepthalate, poly trimethylene terephthalate, poly ethylene naphthalate and combinations thereof.
[0036]. In another embodiment of the present disclosure, the concentration of resin carrier in the master batch composition ranges from about 90 wt% to 80 wt%.
[0037]. The present disclosure furthermore provides a process for preparing masterbatch composition comprising a resin carrier and a branching agent.
[0038]. In an embodiment of the present disclosure, the composition comprising a resin carrier and a branching agent is prepared in Twin screw extruder equipment by processing at temperatures between 220 – 245°C
[0039]. In another embodiment of the present disclosure, the process is carried out at a temperature ranging from about 195 ? to 220?.
[0040]. In an exemplary embodiment of the present disclosure, the process is carried out at a temperature at about 215 ?.
[0041]. In yet another embodiment of the present disclosure, the process is carried out for a time period ranging from about 6 hours to 16 hours, preferably about 6 hours.
[0042]. In still another embodiment of the present disclosure, the process is carried out under nitrogen gas atmosphere.
[0043]. In an embodiment of the present disclosure, the process mentioned above increases more than 50 % solid-state polymerization rate of polyethylene terephthalate comprising
- melt blending a masterbatch composition comprising a resin carrier and a branching agent with polyethylene terephthalate to obtain a melt blended chips of modified polyethylene terephthalate;
- subjecting the melt-blended chips of polyethylene terephthalate to solid-state polymerization to obtain a polyethylene terephthalate with altered intrinsic viscosity.
[0044]. In another embodiment of the present disclosure, the process mentioned above increase more than 50 % solid-state polymerization rate of virgin polyethylene terephthalate comprising
- melt blending a masterbatch composition comprising a resin carrier and a branching agent with virgin polyethylene terephthalate to obtain a melt blended chips of modified polyethylene terephthalate;
- subjecting the melt-blended chips of polyethylene terephthalate to solid-state polymerization to obtain a polyethylene terephthalate with altered intrinsic viscosity.
[0045]. In another embodiment of the present disclosure, the process mentioned above increase more than 50 % solid-state polymerization rate of recycled-polyethylene terephthalate comprising
- melt blending a masterbatch composition comprising a resin carrier and a branching agent with recycled polyethylene terephthalate to obtain a melt blended chips of modified polyethylene terephthalate; and
- subjecting the melt-blended chips of polyethylene terephthalate to solid-state polymerization to obtain a polyethylene terephthalate with altered intrinsic viscosity.

[0046]. 10% Pentaerythritol and 90% PBT were melt mixed in a twin screw extruder with the temperature profile of 220 to 245°C. The masterbatch produced was added during extrusion with rPET / PET at a loading of 1000 ppm. The chips obtained after extrusion found to have higher SSP reactivity (> 40%) compared to PET control.

[0047]. In an embodiment, the present process/set-up for improving solid-state polymerization rate of polyethylene terephthalate is pictorially represented in Figure 1.
[0048]. Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well-known/conventional methods/steps and techniques are omitted so as to not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for examples illustrating the above described embodiments, and in order to illustrate the embodiments of the present disclosure certain aspects have been employed. The examples used herein for such illustration 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 following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLES

EXAMPLE 1: General procedure for preparing Master-batch composition
Brabender twin screw extruder (TSE) with L / D ratio of 46 and 25 mm screw diameter was used for making masterbatch. Resin carrier was dried before processing in the extruder. 10% branching agent and 90% resin carrier was melt mixed in TSE to obtain a master-batch composition.

EXAMPLE 2: Specific procedure for preparing Master-batch composition
Brabender twin screw extruder (TSE) with L / D ratio of 46 and 25 mm screw diameter was used for making masterbatch. PBT was dried at 140°C for 3 hours before processing in the extruder. The feed rate of extruder was kept at 15 kg/hr. 10% Pentaerythritol and 90% PBT was melt mixed in TSE at temperature profile of 220 – 245°C. PBT of intrinsic viscosity 0.86 dl/g was used for compounding with 10% Pentaerythritol. Extruder throughput was kept at 6 kg/ hr and it was processed at 90 rpm. Zones were kept at temperatures between 220 – 245°C.

EXAMPLE 3: General procedure for preparing polyethylene terephthalate with increased intrinsic viscosity:
The master batch composition as prepared in example is was reacted with polyester in TSE at 270 – 285°C. The chips made in the brabender extruder were crystallized at 140°C for 2 hours and subjected to solid state polymerization (SSP). Fluidized bed reactor was used with nitrogen as the carrier gas for SSP. Flow rate of nitrogen was 25 Nm3/ hr. Nitrogen temperature was maintained at 215°C for 6 hours. After SSP, intrinsic viscosity was measured for the chips.

EXAMPLE 4: Specific procedure for preparing polyethylene terephthalate with increased intrinsic viscosity:
The Pentaerythritol masterbatch in PBT produced had an IV of 0.597 dl/g. 0.76 dl/g PET was mixed with 1000 ppm of masterbatch (active content of Pentaerythritol) in a twin screw extruder. It was dried under fine vacuum in a vacuum oven at 140°C for 8 hours.The above blend in TSE was processed at zone temperatures between 270 – 285°C. The IV of chips after extrusion was found to be 0.579 dl/g. The chips containing 1000 ppm of pentaerythritol was crystallized at 140°C for 2 hours and further subjected to solid state polymerization in a fluidized bed reactor. SSP was done for 6 hours and IV increased from 0.579 dl/g to 1.096 dl/g.

EXAMPLE 5: Specific procedure for preparing polyethylene terephthalate with increased intrinsic viscosity:
We mixed rPET chips with 1000 ppm of masterbatch composition in a twin screw extruder. It was dried under fine vacuum in a vacuum oven at 140°C for 8 hours. We processed the above blend in TSE at zone temperatures between 265 – 280°C. The IV of chips after extrusion was found to be 0.521 dl/g. The chips containing 1000 ppm of pentaerythritol was crystallized at 140°C for 2 hours and further subjected to solid state polymerization in a fluidized bed reactor. SSP for done for 6 hours at 215°C and IV increased from 0.521 dl/g to 0.847 dl/g.

Comparative example 1:
PET control of 0.76 dl/g was processed in a twin screw extruder. It was dried under fine vacuum in a vacuum oven at 140°C for 8 hours before processing in twin screw extruder at zone temperatures between 270 – 285°C. The IV of chips after extrusion was found to be 0.575 dl/g. It was crystallized at 140°C for 2 hrs and further subjected to solid state polymerization in a fluidized bed reactor. SSP for done for 6 hours at 215°C and IV increased from 0.575 dl/g to 0.896 dl/g. From example 4 it is evident that when the SSP of PET was carried out in the presence of masterbatch composition the IV is increased from 0.579 dl/g to 1.096 dl/g, whereas in the absence of masterbatch composition the IV is increased from 0.575 dl/g to 0.896 dl/g. Thus, this comparative study demonstrates the significance of masterbatch composition in improving the SSP of PET.

Comparative example 2:
rPET chips were dried under fine vacuum in a vacuum oven at 140°C for 8 hours. It was processed in TSE at zone temperatures between 265 – 280°C. The IV of chips after extrusion was found to be 0.532 dl/g. After extrusion, chips was crystallized at 140°C for 2 hrs and further subjected to solid state polymerization in a fluidized bed reactor. SSP for done for 6 hours at 215°C and IV increased from 0.532 dl/g to 0.782 dl/g. From example 5 it is evident that when the SSP of rPET was carried out in the presence of masterbatch composition the IV is increased from 0.521 dl/g to 0.847 dl/g, whereas in the absence of masterbatch composition the IV is increased from 0.532 dl/g to 0.782 dl/g. Thus, this comparative study demonstrates the significance of masterbatch composition in improving the SSP of rPET.

ADVANTAGES
[0049]. The present disclosure provides advantages including but not limiting to the following:
(a) the present process increases the solid-state polymerization rate to prepare polyethylene terephthalate with altered intrinsic viscosity;
(b) the present process requires reduced time to yield the product; and
(c) time consumption for the present process is minimal, wherein the process is completed in about 6 hours compared to batch process which takes much longer time for completion.
(d) the present process is cost effective/economical due to the above-mentioned features.

[0050]. Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based on the description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well-known/conventional methods and techniques are omitted so as to not unnecessarily obscure the embodiments herein.

[0051]. The foregoing description of the specific embodiments fully reveals 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 in this disclosure have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

[0052]. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” wherever used, 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.

[0053]. With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

[0054]. Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

[0055]. While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.