FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; Rule 13)
A catalyst system for preparation of polyethylene and method of its
preparation
RELIANCE INDUSTRIES LTD.
an Indian Company
of 3rd Floor, Maker Chamber-IV, 222, Nariman Point,
Mumbai 400 021, Maharashtra, India.
Inventors: Ayodhya Srinavasacharya Ramacharya , Kelkar Anil Krishna, Limaye Chetan Vijay , N. Krishna Rao, Sudan Pushap, Shivamurthy Padadayya Jadimath, Upadhye Kuldip Suryaprakash ,BhangaIe Vikas Kadu
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE
MANNER IN WHICH IT IS TO BE PERFORMED

Field of the Invention:
This invention relates to a polyester composition comprising inorganic toners and a process for preparation thereof. The present invention also relates to a toner composition.
Background
Several organic toners that are used in the manufacture of polymers and especially PET are also known but they are associated with drawbacks which include lower thermal stability at polyester polymerization temperature and coarser particle size which may cause agglomeration and thus lead to problems of frequent polymer filter choking in continuous polyester plant.
Inorganic compounds such as ultramarine blue and iron oxide with zinc oxide have been used as coloring agents/colorants in amounts in excess of lOOppm to 50,000ppm in the manufacture of flame retardant polymers, textiles etc. For example, US20110086225 discloses a flame retardant polyester composition comprising zinc oxide and/or ultramarine blue as coloring agent in the range of 100-50,000 ppm.
US20040266920 discloses a colored synthetic fiber produced by melt blending fiber-forming polyamide(s), thermoplastic polyester(s), and colorant comprising organic

and/or inorganic pigments. The colorants can be zinc oxide and/or ultramarine blue in the range of 0.1 to 8 wt%
US20030129398 discloses an article, e.g. cloth formed by melt blending of colorant with water-insoluble alkylene aryl polyester sulfonate salt copolymer, and forming colorant polyester sulfonate mixture; combining the colorant polyester sulfonate mixture with a polyamide or polyester resin in the melt; and forming the melt into an article. The colorants can be zinc oxide and/or ultramarine blue in the range of 0.1 to 8 wt%.
None of the prior art documents however provide a composition for manufacture of preforms, containers, especially bottles ,films, thermoformed sheets and containers , fibers that employ inorganic pigments not as colorants but as color toners.
Definition:
As used in the present specification, the following words and phrases are generally intended to have the meanings as set forth below, except to the extent that the context in which they are used indicate otherwise.
The term toner in the context of the specification means an agent that is incorporated in the resin in minute quantities (1 to 50 ppm) only for the sake of correcting the yellowness of the resin caused on account of the degradation at higher polymerization temperature

The term colorant means an agent incorporated in the resin in larger quantities(100ppm to 50,000 ppm) with or without pigments and dyes for the sake of imparting a color to the resin.
Objects of the Invention
It is an object of the present invention to provide a polyester composition comprising inorganic toners for the manufacture of preforms bottles, containers, films, thermoformed sheets and containers and fibers.
It is yet another object of the present invention to provide a process for preparation of a polyester composition for the manufacture of fibers, preforms, bottles, containers, films, thermoformed sheets and containers that comprises inorganic toners.
It is an object of the present invention to provide an inorganic toner composition.
Summary of the Invention:
In accordance with the present invention there is provided a polyester composition comprising Polyethylene terephthalate, at least one inorganic toner selected from the group consisting of ultramarine blue and iron oxide in an amount in the range of about 1

to about 50 ppm calculated with respect to the total mass of the composition, and a zinc
compound.
In accordance with one embodiment of the present invention, the polyester resin
composition of the present invention further comprises a phosphorous compound.
Typically, the zinc compound is selected from the group comprising zinc oxide, zinc carboxylate, and elemental zinc while the phosphorous compound is typically selected from the group consisting of orthophosphoric acid (OPA), phosphoric acid, triethylphosphonoacetate (TEPA).
In one of the embodiments the polyester resin composition of the present invention further comprises one or more co-monomers selected from isophthalic acid, neopentyl glycol, Methyl Propane Diol, cyclohexane dimethanol, naphthalene dicarboxylic acid, and adipic acid.
Typically, the weight ratio of elemental zinc to elemental phosphorous is about 3:2 calculated with respect to the mass of the polyester composition.
Typically, the amount of zinc as elemental zinc is in the range 5 to 50 ppm calculated with respect to the mass of the polyester composition.

In accordance with another aspect of the present invention there is also provided container, film, fiber, and thermoformed sheet, thermoformed container, made from the composition of the present invention.
In accordance with still another aspect of the present invention there is provided a preform made from the composition of the present invention characterized by L* value in the range of about 65 to 75, b* value in the range of 2.0 to 4.0 and percentage haze in the range of about 3.0 to 6.5.
In accordance with a further aspect of the present invention there is provided a process for preparation of a polyester composition comprising the following steps : -esterifying terephthalic acid or ester thereof with ethylene glycol to obtain a pre-polymer and subjecting the pre-polymer containing reaction mixture to polymerization in the presence of an antimony based polymerization catalyst to obtain polyethylene terephthalate polymer;
-incorporating at least one inorganic toner, selected from the group consisting of ultramarine blue and iron oxide in an amount in the range of about 1 to about 50 ppm calculated with respect to the total mass of the polyester composition along with a zinc

compound either before, during or after the esterification but essentially before polymerization.
In accordance with one embodiment of the present invention, the process of the present invention further comprises incorporation of a phosphorous compound in the reaction mixture.
In accordance with one of the embodiments of the process of the present invention the zinc compound and the phosphorous compound are incorporated independently at any stage before polymerization but essentially before the addition of the antimony based polymerization catalyst.
In accordance with one embodiment of the present invention, the zinc compound and
the phosphorous compound are incorporated as a premix at any stage before
polymerization.
Typically, the zinc compound is selected from the group comprising zinc oxide, zinc
carboxylate, and elemental zinc.

In accordance with still another embodiment of the present invention, the inorganic toner, the zinc compound and phosphorous are incorporated as a premix in the reaction mixture at any stage before polymerization.
Typically, the phosphorous compound is selected from the group consisting of orthophosphoric acid (OPA), phosphoric acid, triethylphophonoacetate (TEPA).
Typically, the amount of zinc as elemental zinc is in the range 5 to 50 ppm calculated with respect to the mass of the polyester composition. Typically, the weight ratio of elemental zinc to elemental phosphorous is about 3:2 calculated with respect to the mass of the polyester composition.
In accordance with one of the embodiments of the present invention, the premix is incorporated through monoethylene glycol medium.
In a further aspect, the present invention also provides an inorganic toner composition for polyesters, comprising inorganic compounds selected from the group consisting of ultramarine blue and iron oxide; a zin comound and optionally a vehicle.
In accordance with one embodiment, the inorganic toner composition of the present invention also comprises a phosphorous compound. Typically, the phosphorous

compound is at least one selected from the group consisting of orthophosphoric acid (OP A), phosphoric acid, triethylphophonoacetate (TEPA).
The weight ratio of elemental zinc to elemental phosphorous in the inorganic toner composition of the present invention is about 3:2.
The vehicle used in the inorganic toner composition of the present invention is typically monoethylene glycol. The zinc compound present in the inorganic toner composition of the present invention is typically selected from the group that includes zinc oxide, zinc carboxylate, and elemental zinc.
Detailed Description of the Invention:
In one aspect, the present invention provides a polyester resin composition of Polyethylene terephthalate (PET) meant for the manufacture of preforms, containers, bottles, polyester films, fibres and thermoformed sheets and containers made out of it, that comprises inorganic toners and a zinc compound. The zinc compound is typically at least one selected from the group consisting of zinc oxide, zinc carboxylate, and elemental zinc.

In accordance with one of the embodiments of the present invention, the polyester resin composition of Polyethylene terephthalate (PET) comprises inorganic toners, a zinc compound and a phosphorous compound. The phosphorous compound present in the resin composition of the present invention is typically selected from the group that includes phosphoric acid, orthophosphoric acid(OPA) and triethyl phosphonoacetate (TEPA). The weight ratio of elemental Zn: P is 3:2 in the resin composition of the present invention calculated with respect to the total mass of the composition.
The inorganic toners present in the polyester resin composition of the present invention, include ultramarine blue and or iron oxide. These inorganic toners are thermally more stable than the organic toners. Moreover, the particle size of these toners is in the range of 0.5-5 microns (D50 value) (compared to 20-30 micron size for organic toners) which results in better dispersion in polyester matrix.
The proportion of the inorganic toner present in the resin composition of the present invention is typically in the range of 1 to 50ppm.
Optionally, the resin composition of the present invention also comprises co-monomers which include isophthalic acid, neopentyl glycol, Methyl Propane Diol, cyclohexane dimethanol, naphthalene dicarboxylic acid, adipic acid and the like.

In another aspect of the present invention there is provided a preform made from the
resin composition of the present invention characterized by L* value in the range of
about 65 to 75, b* value in the range of 2.0 to 4.0 and percentage ha: range of
about 3.0 to about 6.5%.
In still another another aspect, the present invention also provides a container, film, fiber, thermoformed sheets and containers made from the resin composition of the present invention.
In yet another aspect of the present invention, there is provided a process for preparation of a polyester resin composition for the manufacture preforms, bottles, films, fibers, transparent sheets and containers, said process comprising the following steps:
-esterifying terephthalic acid or ester thereof with ethylene glycol to obtain a pre-polymer and subjecting the pre-polymer containing reaction mixture to polymerization in the presence of an antimony based polymerization catalyst to obtain polyethylene terephthalate polymer;
-incorporating at least one inorganic toner, selected from the group consisting of ultramarine blue and iron oxide in an amount in the range of about 1 to about 50 ppm calculated with respect to the total mass of the polyester composition along with a zinc

compound either before, during or after the esterification but essentially before polymerization.
In accordance with one embodiment of the present invention, the process of the present invention further comprises incorporation of a phosphorous compound in the reaction mixture at any stage before polymerization.. Typically, the phosphorous compound is at least one selected from the group consisting of orthophosphoric acid (OPA), phosphoric acid, triethylphophonoacetate (TEPA).
In accordance with one of the embodiments of the process of the present invention the zinc compound and the phosphorous compound are incorporated independently at any stage before polymerization but essentially before the addition of the antimony based polymerization catalyst.
The incorporation of the zinc and phosphorous compound before the addition of antimony avoids the interaction of the phosphorous compound with antimony.
In accordance with one embodiment of the present invention, the zinc compound and the phosphorous compound are incorporated as a premix at any stage before polymerization.

Typically, the amount of Zinc incorporated in accordance with the process of the present invention ranges between 5 to 50 ppm (as Zn) based on theoretical weight of PET.
The weight ratio of elemental zinc to elemental phosphorous is typically about 3:2 calculated with respect to the mass of the of the polyester composition. The amount of zinc compound, especially zinc oxide has no impact on color and other properties of the polyester resin.
In accordance with one embodiment of the present invention, the premix is incorporated through monoethylene glycol medium during the method step of polymerization.
Typically, the zinc compound that is employed in the process of the present invention is selected from the group comprising zinc oxide, zinc carboxylate, and elemental zinc.
In the premix, the zinc oxide reacts with phosphoric acid to form zinc phosphate which acts as thermal stabilizer during polymerization of polyester resin. This completely obviates the use of free phosphoric acid during polymerization and thus eliminates the problems associated with the presence of free phosphoric acid which include of drop in

reaction rate, frequent choking of polymer filters and adverse impact on gloss of preforms and bottles. It is known that free phosphoric acid can react with the antimony based poly-condensation catalyst leading to antimony phosphate formation which in turn leads to consumption of antimony catalyst hampering the reaction rate. Furthermore, antimony phosphate also gets deposited on polymer filters causing intermittent gray coloration and haze in preform. All of these problems related to the formation antimony phosphate are avoided in case of the process of the present invention since free phosphoric acid does not come in contact with antimony in case of the process of the present invention.
In a further aspect, the present invention also provides an inorganic toner composition for polyesters, comprising inorganic compounds selected from the group consisting of ultramarine blue and iron oxide; a zin comound and optionally a vehicle.
In accordance with one embodiment, the inorganic toner composition of the present invention also comprises a phosphorous compound. Typically, the phosphorous compound is at least one selected from the group consisting of orthophosphoric acid (OPA), phosphoric acid, triethylphophonoacetate (TEPA).
The weight ratio of elemental zinc to elemental phosphorous in the inorganic toner composition of the present invention is about 3:2.

The vehicle used in the inorganic toner composition of the present invention is typically monoethylene glycol. The zinc compound present in the inorganic toner composition of the present invention is typically selected from the group that includes zinc oxide, zinc carboxylate, and elemental zinc.
One of the advantages of the process of the present invention is that it provides a higher degrees freedom to choose toners with or without cobalt without countering any of the adverse effects associated with absence of cobalt.
If cobalt is used as a toner, then also the process of the present invention obviates the method step of preparing a premix of the toner(i.e cobalt) along with phosphorous and adding the same during polymerization.
Technical Advancement:
Avoidance of drop in reaction rate, frequent choking of polymer filters and adverse impact on gloss of preforms bottles, polyester films and thermoformed sheets by incorporation of the thermal stabilizer (e.g. phosphoric acid) either as premix with zinc compound (e.g Zinc oxide) or independently before addition of antimony catalyst Thermal stability of the toners resulting in better color.
Lower particle size of the toners leads to better dispersion in polymer which reduces chance of haze in final product

The details of the invention will further be explained by the way of examples which do not limit the scope of the invention. The individual components in the formulations as given in the examples are maintained in ppm and percentage by weight unless otherwise specified.
Example-1
Table-1 exemplifies data of the recipes with and without the use of inorganic toners at various stages of processing i.e. melt section, SSP and after the preform formation. Resin properties with and without the inorganic toners at various stages of processing are tabulated in Table-1. The entire process was studied by comparing L*, a*, b* values and even calculating the percentage (%) Haze in the final preforms. For standardization stannous oxalate was used.
in the melt section, the recipe with inorganic toners showed comparable brightness (L*= 70.7) and comparable bluish hue (b*= -0.485) as compared with the control recipe [brightness (L*) = 70.2; bluish hue (b*) = -0.556].
After the formation of preforms, though the brightness remained almost the same, there was slight drop in yellowness for the preform with inorganic toners as indicated by the reduced b* values, (4.85 as compared to control 5.57). Furthermore, the % haze of the pre-form was found out to be lower i.e. 5.8%.

Recipe Control Inorganic Blue toner=15ppm+Inorganic Red toner=5ppm
Sb 290 290
1 Stannous Oxalate 70 70
Co 10 NIL
Toner NIL 5

NIL 15
NaOH 25 25
P 25 25
IPA 1.8 1.8
Melt Section Proper ties
PC Time(Min) 108 107
IV 0.627 0.624
L* 70.2 70.70
a* 0.406 -0.77
b* -0.556 -0.485
COOH 27 32
SSP Resin Propertie s

IV 0.774 0.756
L* 88.1 86.8
a* 0.14 -0.95
b* -0.63 -0.85
COOH 23 18
Preform Properties
Process Temp (°C) 285-295 285-295

IV 0.71 0.718
L* 71.5 71.4
a* 0.58 -0.35
b* 5.57 4.85
% Haze 6.5 5.8

xample-2
Table-2 exemplifies data with recipes with combination of inorganic compound (ZnO) and H3PO4 along with Inorganic toners. It was observed that reaction rate in melt section found better as compared to control recipe. It was observed that addition of zinc and phosphoric acid did not affect the brightness as such however, it markedly reduced the yellowness value of the pre-form by 61.18 % (The b* values came down to 2.95, from 7.6). Furthermore, the addition of ZnO and phosphoric acid also caused a significant reduction of about 14.49 % in Haze (%) (the percent Haze was reduced from 6.9 % to 5.9 %). Thus, the pre-form obtained by using a combination of ZnO and Phosphoric acid along with the inorganic pigments exhibited better optical properties such as better brightness and better bluish hue and better clarity
Table-2: Data for trials with inorganic compound and H3PO4 along with Inorganic toners.

ZnO=50 ZnO-50
Recipe Control ppm(active)+H3P04=25 ppm (Active) ppm(active)+H3P04=25 ppm (Active) Premix+Inorganic
Premix+Inorganic Red Red Toner=5 ppm+ Inorganic

Toner=5 ppm+ Inorganic Blue Toner=15ppm Blue Toner=15 ppm
Sb 290 290 290
Stannous oxalate 70 70 70
Co 10 NIL NIL
Toner NIL 5 5

NIL 15 15
NaOH 25 25 25
IPA 1.8 1.8 1.8
Melt Section Properties
EI(Min) 219 196 204
PC Time(Min) 105 96 98
IV 0.624 0.624 0.624
L* 69.5 70.7 69.43
a* 0.77 -0.132 -0.03
b* -1.39 -0.639 -0.755

COOH 22 25 22
SSP Resin Properties

IV 0.78 0.778 0.775
L* 84.2 83.2 83.0
a* 0.055 -0.414 -0.478
b* 0.478 -0.543 -0.932
COOH 18 16 17
AA 0.66 0.65 0.53
Preform Properties
Process Temp
(°C) 280-295 280-295 280-295

IV 0.709 0.715 0.713
L* 68.9 72.1 72.2
a* 1.07 -0.28 -0.26
b* 7.6 3.7 2.95
% Haze 6.9 5.9 6.1
AA 7.9 7.1 6.9

IV Drop (dl/g) 0.071 0.063 0.062
Example-3
Table-3 exemplifies data of thermal stability with respect to particle size for Organic and Inorganic toners. From the data in Table-3 the correlation between the thermal stability and particle size of the pigment is clearly evident. Lesser is the particle size; better is its thermal stability.
Table-3: TGA data and particle size data for toners (Note: - Isothermal TGA carried out at 295°C for 1 hour in nitrogen gas atmosphere).

Thermal Stability Maximum Particle USFDA
Toners Nature (% Wt loss @295°C for lHr) Size (microns) Status
Supplier 1 Organic 20.60 20-30 yes
Blue
Supplier 1 Organic 8.63 20-30 yes
Red

Supplier 2Blue Organic 20.9 20-30 yes
Supplier 2Red Organic 5.63 20-30 yes
Inorganic Blue Inorganic 0.68 4-5 yes
Inorganic Red Inorganic 0.43 2-3 yes
Example-4:
Table-4: Fiber grade recipes with and without toner.

Recipe Control Fiber grade Control fiber grade +Inorganic blue toner = 10
ppm
Sb (ppm) 290 290
NaOH (ppm) 25 25
%Ti02 0.26 0.26
EI(Min) 229 227

PC Time(Min) 87 92
IV 0.617 0.616
L* 81.6 82.5
a* -2.08 -2.56
b* 3.5 1.39
COOH 32 37
From the Example-4 it is clear that there is significant reduction in b* color and improvement in L* color with the addition of inorganic toner. Melt polymerization rate is comparable.
Example-5
Recycling of PET :

SrNo Recipes L* a* b*
1 Control flakes 50.33 2.28 9.21
2 Control flakes + ultramarine blue toner = SOppm 51.50 0.64 8.05
• Increase in L* observed whereas b* color found slightly decreased with the addition of blue toner at 50 ppm loading compared to control flakes

These flakes are melted and the molten stream is mixed with the prepolymerizer stream of regular PET polymerization process described in this invention followed by the polymerization step.
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 to the design and construction 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.
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.

We claim,
1. A polyester composition comprising Polyethylene terephthalate, at least one inorganic toner selected from the group consisting of ultramarine blue and iron oxide in an amount in the range of about 1 to about 50 ppm calculated with respect to the total mass of the composition, and a zinc compound.
2. The polyester composition as claimed in claim 1, further comprising a phosphorous compound.
3. The polyester composition as claimed in claim 1 wherein the zinc compound is selected from the group comprising zinc oxide, zinc carboxylate, and elemental zinc.
4. The polyester composition as claimed in claims 1 and 2 wherein the phosphorous compound is selected from the group consisting of orthophosphoric acid (OPA), phosphoric acid, triethylphophonoacetate (TEPA).
5. The polyester composition as claimed in claim 1, further comprising one or more co-monomers selected from isophthalic acid, neopentyl glycol, Methyl Propane Diol, cyclohexane dimethanol, naphthalene dicarboxylic acid, adipic acid.

6. The polyester composition as claimed in any of the above claims, wherein the weight ratio of elemental zinc to elemental phosphorous is about 3:2 calculated with respect to the mass of the polyester composition.
7. The polyester composition as claimed in any of the above claims wherein the amount of zinc as elemental zinc is in the range 5 to 50 ppm calculated with respect to the mass of the polyester composition.
8. A container, film, fiber, thermoformed sheet, thermoformed container made from the composition as claimed in any of the above claims.
9. A preform made from the composition as claimed in any of the above claims characterized by L* value in the range of about 65 to 75, b* value in the range of 2.0 to 4.0 and percentage haze in the range of about 3.0 to 6.5.
10. A process for preparation of a polyester composition as claimed in claims lto 7, comprising the following steps :
-esterifying terephthalic acid or ester thereof with ethylene glycol to obtain a pre-polymer and subjecting the pre-polymer containing reaction mixture to

polymerization in the presence of an antimony based polymerization catalyst to obtain polyethylene terephthalate polymer;
-incorporating at least one inorganic toner, selected from the group consisting of ultramarine blue and iron oxide in an amount in the range of about 1 to about 50 ppm calculated with respect to the total mass of the polyester composition along with a zinc compound either before, during or after the esterification but essentially before polymerization.
11. The process as claimed in claim 10 further comprises incorporation of a
phosphorous compound. 12.The process as claimed in claims 10 and II, wherein the zinc compound and the
phosphorous compound are incorporated independently at any stage before
polymerization and essentially before the addition of the antimony based
polymerization catalyst.
13. The process as claimed in claims 10 and 11, wherein the zinc compound and the phosphorous compound are incorporated as a premix at any stage before polymerization.
14. The process as claimed in claims 10 to 13, wherein the zinc compound is selected from the group comprsing zinc oxide, zinc carboxylate, and elemental zinc.

15. The process as claimed in claims 10 to 13, wherein the phosphorous compound is selected from the group consisting of orthophosphoric acid (OPA), phosphoric acid, triethylphophonoacetate (TEPA).
16. The process as claimed in claims 10 to 15, wherein the inorganic toner, the zinc compound and phosphorous are incorporated as a premix in the reaction mixture at any stage before polymerization.
17. The process as claimed in claim 10 to 16, wherein the amount of zinc as elemental zinc is in the range 5 to 50 ppm calculated with respect to the mass of the polyester composition.
18. The process as claimed in claim 10 to 16, wherein the weight ratio of elemental zinc to elemental phosphorous is about 3:2 calculated with respect to the mass of the polyester composition.
19. The process as claimed in claims 13 and 16, wherein the premix is incorporated through monoethylene glycol medium.

20. An inorganic toner composition for polyesters comprising inorganic compounds
selected from the group consisting of ultramarine blue and iron oxide; a zin
compound and optionally a vehicle.
21. An inorganic toner composition for polyesters as claimed in claim 19 further comprising a phosphorous compound.
22. An inorganic toner composition for polyesters as claimed in claim 20, wherein the phosphorous compound is at least one selected from the group consisting of orthophosphoric acid (OPA), phosphoric acid, triethylphophonoacetate (TEPA).
23. An inorganic toner composition for polyesters as claimed in claim 20, wherein the wherein the weight ratio of elemental zinc to elemental phosphorous is about 3:2.
24. An inorganic toner composition for polyesters as claimed in claim 19, wherein the vehicle is ethylene glycol.

25. An inorganic toner composition for polyesters as claimed in claim 19, wherein the zinc compound is selected from the group comprsing zinc oxide, zinc carboxylate, and elemental zinc.