EP4655334A1

EP4655334A1 - Stabilizer composition for melt polycarbonate resin production

Info

Publication number: EP4655334A1
Application number: EP23809587.1A
Authority: EP
Inventors: Dwairath Dhar; Rayees Ahamed IMAM; Aaron David Bojarski; Jorge A Garcia Agudo
Original assignee: SABIC Global Technologies BV
Current assignee: SABIC Global Technologies BV
Priority date: 2023-01-27
Filing date: 2023-11-21
Publication date: 2025-12-03
Also published as: WO2024156394A1; CN120569426A

Abstract

The invention relates to a composition (S) comprising a Compound (A) and a Compound (B) suitable to be added during the production of melt polycarbonate resin. The invention further relates to a process for preparing melt polycarbonate resin in two or more reactors arranged in series and involving a step of adding the composition (S). In addition, the invention relates to a melt polycarbonate resin obtained by the process of the present invention.

Description

STABILIZER COMPOSITION FOR MELT POLYCARBONATE RESIN PRODUCTION

FIELD OF INVENTION

[0001] The invention relates to a composition suitable to be added during the production of melt polycarbonate resin. The invention further relates to a process for preparing melt polycarbonate resin involving a step of adding the composition. In addition, the invention relates to a melt polycarbonate resin obtained by the process of the present invention.

BACKGROUND

[0002] One of the processes for the production of polycarbonate resins is a melt transesterification process in which a diaryl carbonate such as diphenyl carbonate is reacted with a dihydric phenol. During the course of this reaction, oligomeric by products such as Fries products may be formed. Fries products may be linear or branched, and in particular the presence of linear Fries in polycarbonate resins, have often been associated with detrimental effect on polycarbonate resin. For example, the presence of linear Fries in polycarbonate may cause reduction in thermal stability, impact strength and ductility, increased coloration (or color instability), loss of transparency, and moisture and weather resistance. On the other hand, branched Fries products may result in polycarbonates, which are partially insoluble in conventional solvents such as methylene chloride resulting in the alteration of melt flow properties.

[0003] In addition to Fries products, melt polycarbonate resins may contain phenolic reaction products formed during polycarbonate production. These phenolic reaction compounds may adversely affect the properties of the melt polycarbonate resin and articles prepared from such polycarbonates, such as product de-coloration and crazing (crack formation). In addition, it is required that the content of residual monomers, such as Bisphenol A, comply with government and health regulations, as such monomers if present in high amount may pose a health risk.

[0004] In the past, scavenging agents have been used to reduce the formation of linear Fries and phenolic by-products by end-capping oligomeric chains formed during production. However unless proper caution is exercised, the use of such scavenging agents may result in the formation of undesirably low molecular weight polycarbonate resin. US6590068B2 (“US patent”) describes a method for the preparation of a polycarbonate resin using certain scavenging agents, which help in providing polycarbonate with reduced levels of reactive reaction by-products. Although, the results described in the US patent is promising, the present inventors have found that such scavenging agents may be prone to thermal degradation, which can adversely affect the properties of the final resin.

[0005] US 6,410,777 discloses 1. A salicylic acid ester derivative having a chlorine content of 10 ppm or below and expressed by the following formula (1) in the formula, R1 is methyl group or ethyl group, R2 is an alkyl group having a carbon number of from 1 to 30, an alkoxy group having a carbon number of from 1 to 30, an aryl group having a carbon number of from 6 to 30, an aryl oxy group having a carbon number of from 6 to 30, an aralkyl group having a carbon number of from 6 to 30 or an aralkyl oxy group having a carbon number of from 6 to 30; the group R2 may have, as a substituent, methoxycarbonyl group, ethoxy carbonyl group, 2-(methoxycarbonyl) phenyloxycarbonyl group, 2-(methoxycarbonyl) phenyloxycarbonyloxy group, 2-(ethoxycarbonyl) phenyl oxy carbonyl group, 2-(ethoxycarbonyl) phenyloxycarbonyloxy group or an aryl oxy carbonyl group or aralkyloxycarbonyl group having a carbon number of from 6 to 10. This patent discloses that during the manufacture of this compound a catalyst is used and that if such catalyst remains after the reaction it may be deactivated or neautralised using, for example, an organic sulfonic acid compound.

[0006] US 2003/0100704 discloses A method for preparation of a polycarbonate resin containing reduced levels of reactive reaction by-products comprising the steps of: (a) reacting a diaryl carbonate and a dihydric phenol in a melt transesterification reaction to produce a composition containing polycarbonate polymer, and one or more reaction by-products selected from the group consisting of linear Fries products and monohydric and dihydric phenols; (b) adding to the composition a scavenging agent to form a mixture, said scavenging agent having the formula:

[0007] wherein Ri is alkoxy, phenoxy, benzyloxy or phenyl, and R2 is a substituted or unsubstituted C1-C30 alkyl group, C6-C30 aryl group, C7 -C30 aralkyl group or C6-C30 aryloxy group; (c) processing the mixture at an elevated temperature and for a period of time such that the scavenging agent reacts with linear Fries products to produce end-capped linear Fries products, and with monohydric and dihydric phenols to produce capped monohydric and dihydric phenols and ortho- substituted phenols; and ( d) separating the ortho- substituted phenol from the processed mixture, thereby producing a polycarbonate resin containing reduced levels of reactive reaction by-products.

[0008] EP 0709421 discloses a transesterification method for the manufacture of thermoplastic, solvent-free, polycarbonate with low residual monomer content, characterised in that a polycarbonat having a terminal OH group content < 35% obtained from the transesterification is combined with an acidic component followed by areduction of the partial pressure resulting in a polycarbonate having low amount of residual monomer while having a desired molecular weight.

[0009] US 6,410,777 discloses 1. A salicylic acid ester derivative having a chlorine content of 10 ppm or below and expressed by the following formula (1)

(3)

(wherein R1 and R2 arc each, same or different, a hydrogen atom, a halogen atom or a hydrocarbon group having a carbon number of from 1 to 12; the terms m and n are each, same or different, a number selected from zero and integers of from 1 to 4; in the group A, R3 and R4 are each, same or different, a halogen atom or a monovalent hydrocarbon group having a carbon number of from 1 to 12; R⁵ is an alkylene group having a carbon number of from 3 to 8), the stability of melt viscosity of the polycarbonate is 0.5% or 5 below, the terminal hydroxy group concentration of the polycarbonate is 100 eq/ton or below and the fluorescense spectrum of the polycarbonate (the excitation wavelength of 320 nm (has a relative intensity of fluorescent light of 4.0x10-3 or below at 465 nm based on a standard substance.

[0010] It is an object of the present invention to provide a composition that can help reduce the Fries content and phenolic by-products that are ordinarily present in a melt polycarbonate resin while ensuring sufficiently high molecular weight. Yet another object of the present invention is to provide a process for the production of melt polycarbonate resin using such compositions, to obtain melt polycarbonate resins with improved properties such as color stability and in particular improved resistance to de-coloration. Yet another object of the present invention is to provide a process of producing melt polycarbonate having reduced concentration of residual monomers such as Bisphenol A.

BRIEF DESCRIPTION OF THE DRAWING

[0011] For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0012] FIG. 1 is a schematic diagram illustrating a process for preparing melt polycarbonate in accordance with an embodiment of the present invention. DESCRIPTION

[0013] Accordingly, the one or more objectives of the present invention is achieved by a composition (S) comprising:

• at least one compound (A) represented by formula (I): wherein ‘G’ is a substituent selected from the group consisting of R¹(C=O)-, halogen group, cyano group, and nitro group, wherein the substituent R¹ is independently selected from the group consisting of optionally substituted alkoxy group, optionally substituted phenoxy group, optionally substituted benzyloxy group, and optionally substituted phenyl group; and wherein the substituent R² is independently selected from the group consisting of optionally substituted C1-C40 alkyl group, optionally substituted Ce-Cso aryl group, optionally substituted C7- C30 aralkyl group, and optionally substituted C6-C30 aryloxy group; and

• at least one compound (B) selected from the group consisting of organosulfonic acid, organosulfonic acid ester, phosphoric acid, gluconic acid, gluconic acid based salts and esters, ethylene diamine tetra-acetic acid, citric acid, citric acid based salts and esters, and any combination thereof; preferably compound (B) is selected from the group consisting of aryl sulfonic acid, aryl sulfonic acid ester, bridged aryl sulfonic acid ester and combination thereof;

• wherein the compound (B) is present in an amount from 150.0 parts per million by weight to 1000.0 parts per million by weight, with regard to the total weight of the compound (A);

• wherein the compound (A) is asymmetrical relative to a longitudinal axis passing through the carbon atom attached to the substituent ‘R²’. [0014] The term asymmetrical as used herein with regard to the compound (A) means that the substituents ‘G’ and ‘R²’ are so selected such that the compound (A) is rendered unsymmetrical relative to a longitudinal axis passing through the carbon atom attached to the substituent ‘R²’.

[0015] Preferably, wherein the compound (B) is present in an amount from 150.0 parts per million by weight to 600.0 parts per million by weight, with regard to the total weight of the compound (A). More preferably the compound (B) is present in an amount from 175 to 550 such as from 200 to 500 parts per million by weight, with regard to the total weight of the compound (A).

[0016] Preferably, the substituent ‘G’ is R¹(C=O)-. Preferably, the composition (S) comprises:

• at least one compound (A) represented by formula (II): wherein the substituent R¹ is independently selected from the group consisting of optionally substituted alkoxy group, optionally substituted phenoxy group, optionally substituted benzyloxy group, and optionally substituted phenyl group, preferably the substituent R¹ is an optionally substituted alkoxy group; and wherein the substituent R² is independently selected from the group consisting of optionally substituted C1-C40 alkyl group, optionally substituted Ce- Cso aryl group, optionally substituted C7-C30 aralkyl group, and optionally substituted Ce- C30 aryloxy group, preferably the substituent R² is an optionally substituted C6-C30 aryloxy group; and

• at least one compound (B) selected from the group consisting of organosulfonic acid, organosulfonic acid ester, phosphoric acid, gluconic acid, gluconic acid based salts and esters, ethylene diamine tetra-acetic acid, citric acid, citric acid based salts and esters and any combination thereof; preferably compound (B) is selected from the group consisting of aryl sulfonic acid, aryl sulfonic acid ester, bridged aryl sulfonic acid ester and combination thereof; • wherein the compound (B) is present in an amount from 150.0 parts per million by weight to 1000.0 parts per million by weight, with regard to the total weight of the compound (A); and

• wherein the compound (A) is asymmetrical relative to a longitudinal axis passing through the carbon atom attached to the substituent ‘R²’.

[0017] The inventors surprisingly found that when the composition (S) is added during the process of producing melt polycarbonate, the resultant polycarbonate has reduced content of Fries product and residual phenolic by-products while retaining the desired molecular weight. In particular, the inventors also found that the resultant melt polycarbonate obtained from the process involving the step of adding composition (S), has reduced dihydric phenol content such as Bisphenol A.

[0018] The term “Fries product” as used in this disclosure means linear Fries product and branched Fries product. Such Fries product may be derived from BPA polycarbonate moieties upon undergoing Fries arrangement in the presence of basic catalysts, during the production of the polycarbonate resin. The term “linear Fries product” as used in this disclosure means structural units represented by the formula below:

[0019] The term “branched Fries product” as used in this disclosure means structural units represented by the formula below:

[0020] The term “residual phenolic by-products” as used in this disclosure means unreacted dihydric phenol and unreacted monohydric phenol. [0021] The term “optionally substituted” means substitution by hydrogen, an alkyl group having 1-20 carbon atoms, a branched alkyl group having 1-20 carbon atoms, an aryl group having 6-30 carbon atoms, an alkyl group having aromatic substitutions, halogen group, amine group, hydrocarbon group containing at least one hetero atom selected from oxygen, nitrogen and sulfur. [0022] In an aspect of the invention, the invention is directed to the use of the composition (S) for reducing reactive by-product in a melt polycarbonate resin, wherein the reactive by-product is at least one of linear Fries product, unreacted dihydric phenol, unreacted monohydric phenol and combination thereof.

Compound (A)

[0023] The composition (S) comprises of at least one compound (A) represented by formula (I): wherein ‘G’ is a substituent selected from the group consisting of R¹(C=O)-, halogen group, cyano group, and nitro group, wherein the substituent R¹ is independently selected from the group consisting of optionally substituted alkoxy group, optionally substituted phenoxy group, optionally substituted benzyloxy group, and optionally substituted phenyl group; and wherein the substituent R² is independently selected from the group consisting of optionally substituted C1-C40 alkyl group, optionally substituted C6-C30 aryl group, optionally substituted C7-C30 aralkyl group, and optionally substituted C6-C30 aryloxy group. The compound (A) is asymmetrical relative to a longitudinal axis passing through the carbon atom attached to the substituent ‘R²’. The C6-C30 aryl oxy group may be represented by the formula: -O-Ar, where Ar represents an optionally substituted C6-C30 aryl group.

[0024] Preferably, the substituent R¹ is independently selected from optionally substituted alkoxy group, or optionally substituted phenyl group; and wherein the substituent R² is independently selected from optionally substituted C1-C40 alkyl group, or optionally substituted C6-C30 aryloxy group. The C6-C30 aryloxy group may be represented by the formula: -O-Ar, where Ar represents an optionally substituted C6-C30 aryl group.

[0025] In an aspect of the invention, the substituent ‘G’ may be a halogen group and R² is an optionally substituted C6-C30 aryloxy group. Preferably, R² is an optionally substituted phenoxy group. Such a configuration results in the compound (A) to be a halogen substituted diphenyl carbonate provided that compound (A) is asymmetrical.

[0026] Preferably, the substituent ‘G’ is R¹(C=O)-, preferably R¹ is an optionally substituted alkoxy group, preferably R¹ is a methoxy group. Preferably R² is an optionally substituted C6-C30 aryloxy group. Preferably, R² is an optionally substituted phenoxy group. The phenoxy group may be represented by the formula: -O-Ph, where Ph represents an optionally substituted phenyl group.

[0027] In an aspect of the invention, R² is a halogen substituted phenoxy group. Preferably, R² is a C1-C30 alkyl substituted phenoxy group. Preferably, R² is an unsubstituted phenoxy group. [0028] Preferably, the substituent ‘G’ is R¹(C=O)- and compound (A) is represented by formula (II):

[0029] wherein the substituent R¹ is independently selected from the group consisting of alkoxy group, phenoxy group, benzyloxy group, and phenyl; and wherein the substituent R² is independently selected from the group consisting of C1-C40 alkyl group, optionally substituted Ce- Cso aryl group, optionally substituted C7-C30 aralkyl group, and optionally substituted Ce- C30 aryloxy group. The compound (A) is asymmetrical relative to a longitudinal axis passing through the carbon atom attached to the substituent ‘R²’.

[0030] Preferably, the substituent R¹ is an optionally substituted alkoxy group. Preferably, the substituent R¹ is an alkoxy group having 1 to 10 carbon atoms. Preferably, the substituent R¹ is a methoxy group, an ethoxy group, a propyloxy group or a butoxy group. Preferably R¹ is a methoxy group.

[0031] Preferably, the substituent R² is an optionally substituted C6-C30 aryloxy group. Preferably, the substituent R² is an optionally substituted phenoxy group. Preferably, the substituent R¹ is a methoxy group and the substituent R² is a phenoxy group. The phenoxy group may be represented by the formula: -O-Ph, where Ph represents an optionally substituted phenyl group.

[0032] In some aspects of the invention, R² is a halogen substituted C6-C30 aryloxy group.

In some aspects of the invention, R² is a C1-C30 alkyl substituted phenoxy group. In some aspects of the invention, R² is an unsubstituted C6-C30 aryl oxy group.

[0033] Preferably, the compound (A) is at least one compound selected from the group consisting of:

and any combination thereof, wherein ‘X’ is a halogen selected from chlorine, bromine, iodine, and fluorine. Preferably the halogen is chlorine. [0034] Preferably, the compound (A) comprises or consists of a compound represented by the formula:

. Alternatively, the compound (A) comprises or consists of phenyl methyl salicylyl carbonate (PMSC).

Compound (B) [0035] The composition (S) comprises at least one compound (B) selected from the group consisting of organosulfonic acid, organosulfonic acid ester, phosphoric acid, gluconic acid, gluconic acid based salts and esters, ethylene diamine tetra-acetic acid, citric acid, citric acid based salts and esters, and any combination thereof.

[0036] The organosulfonic acid or the organosulfonic acid ester may be represented by the formula:

[0037] wherein each R⁷ is independently a C1-30 alkyl, C1-30 aryl, C7-30 alkylarylene, C7-30 arylalkylene, or a polymer unit derived from a C2-32 ethylenically unsaturated aromatic sulfonic acid or its ester; and R⁸ is independently a hydrogen, C1-24 alkyl, or a group of the formula -S(=0)2- R⁷ wherein R⁷ is a Ce-12 aryl or C7-24 alkylarylene.

[0038] Preferably the compound (B) is selected from an alkylbenzene sulfonic acid, an aryl sulfonic acid, an aryl sulfonic acid ester, bridged aryl sulfonic acid ester, a polystyrene sulfonic acid, and a p-toluene sulfonic acid anhydride.

[0039] Preferably the at least one compound (B) is selected from the group consisting of aryl sulfonic acid, aryl sulfonic acid ester, bridged aryl sulfonic acid ester and combination thereof. [0040] Preferably the at least one compound (B) is selected from the group consisting of aryl sulfonic acid, or aryl sulfonic acid ester. Preferably, the aryl sulfonic acid ester is selected from p-toluene sulfonic acid or butyl p-toluenesulfonate (n-butyl tosylate).

[0041] Preferably, the compound (B) comprises or consists of n-butyl tosylate (BuTos). Composition (S)

[0042] Preferably, the composition (S) comprises:

• at least one compound (A) represented by formula (II): wherein the substituent R¹ is an alkoxy group; and wherein the substituent R² is a C6-C30 aryloxy group; and

• at least one compound (B) selected from the group consisting of organosulfonic acid, organosulfonic acid ester, phosphoric acid, gluconic acid, gluconic acid based salts and esters, ethylene diamine tetra-acetic acid, citric acid, citric acid based salts, and any combination thereof; preferably compound (B) is selected from the group consisting of aryl sulfonic acid, aryl sulfonic acid ester, bridged aryl sulfonic acid ester and combination thereof.

[0043] Preferably, compound (A) comprises or consists of phenyl methyl salicylyl carbonate (PMSC) and the compound (B) comprises or consists of n-butyl tosylate.

[0044] In accordance with the invention, the amount of compound (B) is at least 150 parts per million by weight with regard to the total weight of compound (A). Preferably the compound (B) is present in an amount from 150.0 parts per million by weight to 1000.0 parts per million by weight, preferably 150.0 parts per million by weight to 600.0 parts per million by weight, preferably in an amount from 150.0 parts per million by weight to 580.0 parts per million by weight., preferably in an amount from 170.0 parts per million by weight to 560.0 parts per million by weight, preferably in an amount from 180.0 parts per million by weight to 300.0 parts per million by weight, with regard to the total weight of the compound (A).

[0045] If the content of compound (B) is beyond the upper limit prescribed herein, the molecular weight buildup of the melt polycarbonate may be adversely affected during its production. On the other hand if the content of Compound (B) is below the lower limit prescribed herein, the desired stabilization of the Compound (A) will not be achieved.

[0046] Preferably, wherein the composition (S) comprises:

• the compound (A) comprises or consists of phenyl methyl salicylyl carbonate (PMSC) represented by the formula: and

• the compound (B) comprises or consists of n-butyl tosylate, wherein the compound (B) is present in an amount from 150.0 parts per million by weight to 1000.0 parts per million by weight, preferably in an amount from 150.0 parts per million by weight to 580.0 parts per million by weight, preferably in an amount from 150.0 parts per million by weight to 580.0 parts per million by weight, preferably in an amount from 170.0 parts per million by weight to 560.0 parts per million by weight, preferably in an amount from 180.0 parts per million by weight to 300.0 parts per million by weight, with regard to the total weight of the compound (A).

[0047] The inventors surprisingly found that when the compound (A) and the compound (B) is mixed at a certain proportion, the resultant composition (S) has improved thermal stability especially under temperature conditions typically used during the production of melt polycarbonate. As a result, the extent of chemical species produced due to thermal degradation is minimized during the production of the melt polycarbonate resin. This is particularly beneficial, as often the presence of such species may adversely affect the quality of the polycarbonate resin so obtained.

[0048] For example, when the compound (A) is phenyl methyl salicyl carbonate (PMSC), the inventors found that unless the compound PMSC is stabilized with Compound (B) such as n- butyl tosylate, the PMSC may undergo thermal degradation as shown in the reaction below, producing species such as diphenyl carbonate and bis(methyl salicyl) carbonate (BMSC): [0049] The presence of undesired amounts of diphenyl carbonate (DPC), especially during the later stages of production of a melt polycarbonate, may result in a final polycarbonate resin having undesirably lower molecular weight. Further, the presence of symmetrical salicylate carbonate such as BMSC may result in the incorporation of salicylate end-groups, which are undesirable to the stability of the resin.

[0050] The composition (S) may be prepared by uniformly dispersing the compound (B) in compound (A). The uniform dispersion may be achieved using a recirculation pump.

Process for producing a melt polycarbonate resin

[0051] In an aspect of the invention, the invention relates to a process for preparing a melt polycarbonate resin comprising the step of reacting one or more dihydric phenol compound with one or more diaryl carbonate compound in molten state and in at least two reactors positioned in series, wherein the process comprises the step of adding the composition (S) in accordance with the invention, prior to the melt polycarbonate resin leaving a final reactor.

[0052] Preferably, wherein the composition (S) is added to an oligomeric reaction product of one or more dihydric phenol compound and one or more diaryl carbonate compound prior to the melt polycarbonate resin leaving the final reactor.

[0053] Preferably, wherein the composition (S) is added to an oligomeric reaction product of one or more dihydric phenol compound and one or more diaryl carbonate compound after such an oligomeric reaction product has reached a weight average molecular weight of at least 10,000 g/mol as determined with gel permeation chromatography using polystyrene standard in accordance with ASTM D5296-11.

[0054] Preferably, the composition (S) is added to an oligomeric reaction product of one or more dihydric phenol compound and one or more diaryl carbonate compound, prior to such an oligomeric reaction product being introduced in the final reactor.

Reactants

[0055] The process for preparing the melt polycarbonate resin involves a melt transesterification reaction between diaryl carbonate and dihydric phenol. The dihydric phenol may be an aromatic dihydroxy compound. The diaryl carbonate is selected from the group consisting of diphenyl carbonate, ditolyl carbonate, halogen substituted diphenyl carbonate, m- cresyl carbonate, and dinaphthyl carbonate and combination thereof; and/or wherein the dihydric phenol is selected from the group consisting of bis(4-hydroxyphenyl)methane, l,l-bis(4- hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis(4- hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-l-methylphenyl)propane, l,l-bis(4-hydroxy-t-butylphenyl) propane, 2,2-bis(4- hydroxy-3-bromophenyl)propane, l,l-(4-hydroxyphenyl) cyclopentane, l,l-bis(4- hydroxyphenyl)cyclohexane, 4,4 '-dihydroxy diphenyl ether, 4, 4 'dihydroxy-3, 3 '-dimethylphenyl ether, 4,4'-dihydroxydiphenyl sulphide, 4, 4'-dihydroxy-3, 3 '-dimethyldiphenyl sulfide, 4,4'- dihydroxydiphenyl sulfoxide, 4, 4'-dihydroxy-3, 3 '-dimethyldiphenyl sulfoxide, 4,4'- dihydroxydiphenyl sulfone, 4, 4 '-dihydroxy-3, 3 '-dimethyldiphenyl sulfone and combination thereof.

[0056] Preferably the diaryl carbonate comprises or consists of diphenyl carbonate (DPC) and the dihydric phenol comprises or consists of 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A).

Reactors used

[0057] The term “positioned in series” as used throughout this disclosure with reference to the reactors, means a sequential arrangement of at least two reactors such that except for the final reactor, a reaction product obtained in any reactor is introduced into an immediately subsequent reactor positioned downstream to the reactor and wherein the final reactor is the reactor where the melt polycarbonate resin is produced and leaves the reactor. Alternatively, the final reactor may be defined as the reactor positioned downstream relative to the remaining reactors positioned in the series. Accordingly, if there are four reactors arranged in series for the production of melt polycarbonate, the fourth reactor is the final reactor and the melt polycarbonate leaves from the fourth reactor in the series.

[0058] The numbers of reactors arranged in series is at least two and at most ten, preferably at least three and at most six. Preferably, the number of reactors arranged in series is four. The reactors used for preparing the melt polycarbonate may be a combination of at least one oligomerization reactor and at least one polymerization reactor.

[0059] The oligomeric reaction product obtained from the oligomerization reactor may be less than 10,000 g/mol, preferably less than 8,000 g/mol, preferably less than 5,000 g/mol as determined with gel permeation chromatography using polystyrene standard in accordance with ASTM D5296-11. The oligomeric reaction product obtained from the polymerization reactor is at least 10,000 g/mol, preferably at least 15,000 g/mol, preferably at least 20,000 g/mol as determined in accordance with gel permeation chromatography using polystyrene standard in accordance with ASTM D5296-11.

[0060] The at least one oligomerization reactor may be operated at any temperature ranging from 200 °C to 310 °C, preferably in the range from 250 °C to 290 °C, preferably in the range from 250 °C to 280 °C. The at least one oligomerization reactor may be operated at any pressure ranging from 5.0 millibar to 210.0 millibar, preferably ranging from 10.0 millibar to 200.0 millibar, preferably ranging from 50.0 millibar to 190.0 millibar.

[0061] The at least one polymerization reactor may be operated at any temperature ranging from 280 °C to 310 °C, preferably in the range from 290 °C to 305 °C. The at least one polymerization reactor may be operated at any pressure ranging from 0.5 millibar to 10.0 millibar, preferably 0.5 millibar to 5.0 millibar, preferably ranging from 1.0 millibar to 3.0 millibar. Addition of Compound (S)

[0062] The composition (S) may be added in an amount from 0.1 wt.% to 10.0 wt.%, preferably in an amount from 0.2 wt.% to 5.0 wt.%, preferably in an amount from 0.3 wt.% to 1.0 wt.%, with regard to the total weight of the melt polycarbonate resin.

[0063] The addition of composition (S) may be in the solid form or in the molten state. Preferably, the composition (S) is added in the molten form. In an aspect of the invention, the composition (S) is heated to a temperature sufficient to convert the composition to a molten state prior to adding the composition (S). Preferably, prior to adding, the composition (S) is heated to any temperature of at least 70.0 °C and at most 150 °C, preferably to any temperature of at least 80.0 °C and at most 110 °C.

[0064] Preferably, for obtaining the composition (S) under molten form, the composition (S) is heated for at least 10 minutes, preferably at least 20 minutes at any temperature of at least 70.0 °C and at most 150 °C, preferably at any temperature of at least 80.0 °C and at most 110 °C. Preferably, the composition (S) is heated at any temperature of at least 70.0 °C and at most 150 °C, preferably at any temperature of at least 80.0 °C and at most 110 °C and for any time period between 25 minutes to 45 minutes, preferably between 25 minutes to 40 minutes. [0065] Preferably, the composition (S) is added under molten state, preferably wherein the composition (S) is maintained at any temperature of at least 70.0 °C and at most 150 °C, preferably at any temperature of at least 80.0 °C and at most 110 °C, preferably at any temperature of at least 80.0 °C and at most 90 °C, while being added.

[0066] Preferably, the composition (S) is added under molten state, preferably wherein the composition (S) is maintained at any temperature of at least 70.0 °C and at most 150 °C, preferably at any temperature of at least 80.0 °C and at most 110 °C, preferably at any temperature of at least 80.0 °C and at most 90 °C, while being added to an oligomeric reaction product of one or more dihydric phenol compound and one or more diaryl carbonate compound.

[0067] In an aspect of the invention, the process for preparing the composition (S) in the molten state involves the steps of: (a) heating the compound (A) at any temperature of at least 70.0 °C and at most 150 °C, preferably at any temperature of at least 80.0 °C and at most 110 °C, to obtain the compound (A) in a molten form; and (b) dispersing the compound (B) in the molten compound (A) and obtaining the compound (S) in the molten state. Accordingly, the composition (S) in the molten state is at any temperature of at least 70.0 °C and at most 150 °C, preferably at any temperature of at least 80.0 °C and at most 110 °C, preferably at any temperature of at least 80.0 °C and at most 90 °C.

[0068] Alternatively, in an aspect of the invention, the process for preparing the composition (S) in the molten state involves the steps of: (a) dispersing compound (B) in compound (A) to obtain a blended composition; and (b) heating the blended composition at any temperature of at least 70.0 °C and at most 150 °C, preferably at any temperature of at least 80.0 °C and at most 110 °C, and obtaining the compound (S) in the molten state.

[0069] The step of reacting the one or more dihydric phenol compound with one or more diaryl carbonate compound may be carried out in at least one oligomerization reactor and at least one polymerization reactor and wherein the step of adding the composition (S) may be carried out after the reaction in the at least one oligomerization reactor and before or during the reaction in the at least one polymerization reactor. The at least one polymerization reactor is positioned downstream to the at least one oligomerization reactor such that the oligomeric reaction product produced from the at least one oligomerization reactor is introduced into the at least one polymerization reactor. [0070] Preferably, the step of reacting the one or more dihydric phenol compound with one or more diaryl carbonate compound is carried out in two oligomerization reactors and two polymerization reactors, positioned in series such that the composition (S) is added to an oligomeric reaction product of the one or more dihydric phenol compound and the one or more diaryl carbonate compound, obtained after the reaction in the two oligomerization reactors and before or during the reaction in the two polymerization reactors.

[0071] Preferably, the composition (S) is added to an oligomeric reaction product of the one or more dihydric phenol compound and the one or more diaryl carbonate compound obtained after the reaction from a first polymerization reactor and prior to introducing the reaction product in a second polymerization reactor, positioned downstream to the first polymerization reactor.

[0072] The dihydric phenol compound and the diaryl carbonate compound may be mixed together in a mixing vessel positioned upstream to the at least one oligomerization reactor to form a reaction mixture and subsequently the reaction mixture may be introduced into the at least one oligomerization reactor.

[0073] In an aspect of the invention, the process further comprises:

• providing a set of ingredients comprising the melt polycarbonate resin leaving the final reactor and at least one quencher compound, to an extruder (EX); and

• extruding the set of ingredients in the extruder (EX) under conditions sufficient for the quencher compound to deactivate, at least in part, any catalyst residue that is present in the melt polycarbonate resin.

[0074] The quencher compound may be selected from the group consisting of sulfonic acid preferably aryl sulfonic acid, sulfonic acid preferably aryl sulfonic acid ester, bridged aryl sulfonic acid ester, phosphoric acid, gluconic acid, metal salts of gluconic acid, ethylene diamine tetraacetic acid, citric acid and any combination thereof. Preferably the quencher compound may be selected from the group consisting of aryl sulfonic acid, aryl sulfonic acid ester, bridged aryl sulfonic acid ester, and any combination thereof. Preferably the quencher compound is an aryl sulfonic acid. Preferably the quencher compound is n-butyl tosylate (BuTos).

Catalyst

[0075] The process of reacting one or more dihydric phenol compound with one or more diaryl carbonate compound may be carried out in the presence of at least one inorganic transesterification catalyst and optionally in the presence of at least one organic transesterification catalyst. The inorganic transesterification catalyst may comprise an alkali metal based catalyst such as sodium hydroxide, sodium dihydrogen phosphate, potassium dihydrogen phosphate, cesium carbonate, potassium hydroxide and combination thereof.

[0076] Preferably, the inorganic transesterification catalyst is a combination of sodium hydroxide and potassium dihydrogen phosphate. Preferably, the inorganic transesterification catalyst is selected from the group consisting of NaJ PCh, ISfeHPCh, CSH2PO4, CS2HPO4, NaKHPCU, CsNaHPCU, CsKHPCU, and combinations comprising two or more of the foregoing. The inorganic transesterification catalyst may be added to a reaction mixture of diphenyl carbonate and dihydric phenol in the oligomerization reactor in an amount sufficient to form the desired reaction product at high productivity rate.

[0077] The inorganic transesterification catalyst may be added at a catalyst loading expressed as the amount of alkali metal present, in parts per billion by weight, in the dihydric phenol, expressed in kilograms. Preferably, the catalyst loading of the inorganic transesterification catalyst ranges from 10.0 parts per billion by weight to 300.0 parts per billion by weight, preferably from 20.0 parts per billion by weight to 250.0 parts per billion by weight, preferably from 20.0 parts per billion by weight to 150.0 parts per billion by weight, preferably from 20.0 parts per billion by weight to 100.0 parts per billion by weight, of alkali metal with regard to the total weight in kilogram, of the dihydric phenol.

[0078] Preferably, wherein the alkali metal is sodium and dihydric phenol is 2,2-bis(4- hydroxyphenyl)propane (also known as bisphenol A).

[0079] The use of such inorganic transesterification catalyst although increases process productivity, may lead to the formation of Fries product, which in turn may adversely affect the properties of the resultant melt polycarbonate resin. However, the inventors surprisingly found that even when higher amount of inorganic transesterification catalyst is used in the process of the present invention, the amount of Fries product present in the resultant melt polycarbonate resin is sufficiently low while imparting desirably high production productivity.

[0080] The organic transesterification catalyst may be tetra-butyl phosphonium acetate (TBPA). Preferably, the organic catalyst is added to the reaction mixture present in the mixing vessel that is used to mix the diaryl carbonate and dihydric phenol. [0081] Referring to FIG.l, in an aspect of the invention, the process of preparing the melt polycarbonate resin involves the steps of:

• reacting the one or more dihydric phenol compound with one or more diaryl carbonate compound in a first oligomerization reactor (101) to obtain a first reaction product stream (102);

• introducing the first reaction product stream (102) in a second oligomerization reactor (103) and obtaining a second reaction product stream (104);

• introducing the second reaction product stream (104) in a first polymerization reactor (105) and obtaining a third reaction product stream (106); and

• introducing the third reaction product stream (106) into a second polymerization reactor (107) and obtaining the melt polycarbonate resin (108).

[0082] Preferably, the one or more dihydric phenol compound and one or more diaryl carbonate compound may be mixed in a mixing vessel (100) to form a reaction mixture (116) and introducing the reaction mixture (116) into a first oligomerization reactor (101).

[0083] The composition (S) is added to any one of the first reaction product stream (102) or to the second reaction product stream (104) or to the third reaction product stream (106) or combination thereof. Preferably, the composition (S) is added to the second reaction product stream (104) prior to introducing into the first polymerization reactor (105); and/or the composition (S) is added to the third reaction product stream (106) prior to introducing into the second polymerization reactor (107).

[0084] Preferably, the composition (S) is added to the third reaction product stream (106) prior to introducing into the second polymerization reactor (107). The inorganic transesterification catalyst may be added to the first oligomerization reactor (101) and optionally to the second polymerization reactor (107) prior to obtaining the melt polycarbonate resin (108).

[0085] In an aspect of the invention, the composition (S) may be added to the melt polycarbonate (108) prior to introducing the melt polycarbonate into the extruder (109). The extrudate (Hl) obtained from the extruder (109) may be sent to a pelletizer (112) to obtain polycarbonate pellets.

Melt polycarbonate resin

[0086] In an aspect of the invention, the invention relates to a melt polycarbonate resin obtainable by the process as disclosed herein. [0087] Preferably, melt polycarbonate resin obtainable by the process of the present invention has:

• a weight average molecular weight from 25,000 g/mol to 70,000 g/mol determined with gel permeation chromatography using polystyrene standard in accordance with ASTM D5296- 11; and/or

• a linear Fries product content of at most 135.0 parts per million by weight with regard to total weight of the melt polycarbonate resin; and/or

• a dihydric phenol content of less than 20.0 parts per million by weight with regard to total weight of the melt polycarbonate resin.

[0088] Preferably, melt polycarbonate resin obtainable by the process of the present invention has:

• a weight average molecular weight from 25,000 g/mol to 70,000 g/mol determined with gel permeation chromatography using polystyrene standard in accordance with ASTM D5296- i i;

• a linear Fries product content of at most 135.0 parts per million by weight with regard to total weight of the melt polycarbonate resin; and

[0089] Advantageously, the melt polycarbonate resin may be produced using a higher inorganic catalyst loading while minimizing the formation of linear Fries product.

[0090] Preferably the melt polycarbonate is obtainable from a process comprising reacting a dihydric phenol in presence of an inorganic catalyst containing an alkali metal; wherein:

• the process has an inorganic catalyst loading from 10.0 parts per billion by weight to 300.0 parts per billion by weight, preferably from 20.0 parts per billion by weight to 250.0 parts per billion by weight, preferably from 20.0 parts per billion by weight to 150.0 parts per billion by weight, preferably from 20.0 parts per billion by weight to 100.0 parts per billion by weight, of alkali metal with regard to the total weight in kilogram of the dihydric phenol; and

• wherein the melt polycarbonate resin has a linear Fries product content of at most 135.0 parts per million by weight with regard to total weight of the melt polycarbonate resin. [0091] Preferably, wherein the alkali metal is sodium and dihydric phenol is 2,2-bis(4- hydroxyphenyl)propane (also known as bisphenol A).

[0092] Preferably, the melt polycarbonate resin obtainable by the process of the present invention has a dihydric phenol content from 0.0 to less than 20.0 parts per million by weight, preferably 0.0 to less than 18.0 parts per million by weight, with regard to total weight of the melt polycarbonate resin.

[0093] Preferably, the weight average molecular weight ranges from 30,000 g/mol to 65,000 g/mol, preferably from 40,000 g/mol to 60,000 g/mol, determined with gel permeation chromatography using polystyrene standard in accordance with ASTM D5296-11.

[0094] Preferably, the linear Fries product content ranges from 5.0 parts per million by weight to 135.0 parts per million by weight with regard to total weight of the melt polycarbonate resin, preferably from 25.0 parts per million by weight to 120.0 parts per million by weight with regard to total weight of the melt polycarbonate resin, preferably from 75.0 parts per million by weight to 120.0 parts per million by weight with regard to total weight of the melt polycarbonate resin.

[0095] The expression “total Fries product” means the sum total of both linear Fries product and branched Fries product. Preferably, the melt polycarbonate resin obtained by the process of the present invention has a total Fries product content of less than 500.0 parts per million by weight with regard to total weight of the melt polycarbonate resin.

[0096] Preferably, the total Fries product content ranges from 200.0 parts per million by weight to 500.0 parts per million by weight with regard to total weight of the melt polycarbonate resin, preferably from 250.0 parts per million by weight to 450.0 parts per million by weight with regard to total weight of the melt polycarbonate resin, preferably from 300.0 parts per million by weight to 400.0 parts per million by weight, with regard to total weight of the melt polycarbonate resin.

[0097] Methods for determining the amount of Fries product are known to the skilled person and generally include the methanolysis of the polycarbonate followed by HPLC chromatography to identify the total amount of Fries product. Alternatively, NMR techniques can be used to determine the type and amount of these Fries product, such as the respective amounts of linear and branched Fries product. [0098] The inventors surprisingly found that the melt polycarbonate obtained by a process involving a step of adding the composition (S), has sufficiently low content of Fries product, low dihydric phenol residue such as Bisphenol A, while retaining a desirable level of molecular weight. The lower phenol residue in the polycarbonate resin is particularly beneficial for regulatory and health consideration while the lower Fries product content is beneficial for imparting desired color stability and other associated properties.

[0099] A suitable metric to evaluate color stability is by evaluating the Yellowness Index (YI) of a polycarbonate sample before and after subjecting such a sample to thermal aging. A lower increase in Yellowness Index after thermal aging is indicative of improved color stability of the resin.

[00100] The present invention will now be further elucidated based on the following nonlimiting examples.

EXAMPLES

Example I

[00101] Purpose: Demonstrate a process of preparing the melt polycarbonate resin in accordance with the present invention and evaluate the properties of the resultant melt polycarbonate resin. For the purpose of the present example, three melt polycarbonate resin samples were prepared, with sample referenced as ‘IE’ prepared in accordance with the present invention while samples ‘CEE and ‘CE2’ were prepared as comparatives.

[00102] Material: For the purposes of the examples the following materials were used:

Table 1

[00103] Testing protocols: The following test protocols and standard were followed:

Table 2 [00104] Process of preparing melt polycarbonate resin (IE) in accordance with the present invention: The schematic diagram of FIG.1 may be referred to understand one or more features of the process. Bisphenol A (BP A) and diphenyl carbonate (DPC) were mixed in a mixing vessel (100) to form a reaction mixture (116). An appropriate measurement system was provided to adjust the inlet molar ratio (MR) to a value of 1.000 (MR = moles of DPC / moles of BP A). Temperature and pressure was set between 160 °C and 180 °C and 1.0 atmosphere respectively. An organic catalyst TetraButylPhosphonium Acetate (TBPA) was added to the reaction mixture using a water based solution at a concentration of 30-50 pmol TBPA/mol BPA. Subsequently this reaction mixture (116) was fed to a first oligomerization reactor (101).

[00105] In the first oligomerization reactor (101), temperature and pressure were set to 257 °C and 180-155 millibar (mbar). In the first oligomerization reactor (101) the inorganic catalyst was added. The inorganic catalyst comprised a mixture of NaOH and KH2PO4 in water at a loading of 20-150ppb of Na per kg of BPA. The oligomeric reaction product stream (102) obtained from the first oligomerization reactor (101) was sent to a second oligomerization reactor (103), which was operated at a pressure between 5.0 to 37.0 millibar (mbar) and at temperature between 280- 300 °C. The oligomeric reaction product stream (104) obtained from the second oligomerization reactor (103) was sent to the next reactor, a first polymerization reactor (105).

[00106] The first polymerization reactor (105) was a horizontal agitated reactor (agitator type: MEGANE®) that was operated at 290-300 °C and at a pressure between 2.0 to 3.0 mbar.

[00107] To the oligomeric reaction product stream (106) obtained from the first polymerization reactor (105), a composition (Composition S) comprising phenyl methyl salicylyl carbonate (PMSC) and n-butyl tosylate (BuTos) was added. The amount of composition (S) that was added was calibrated to 0.4 wt.% or (4000 ppm) with regard to the total weight of the final melt polycarbonate resin. The mixture so obtained was introduced into a second polymerization reactor (107) (agitator type: MEGANE®) (final reactor of the series) and subsequently the melt polycarbonate resin (108) was obtained. The second polymerization reactor (107) was operated at a temperature between 290-300 °C and at pressure between 1.0 and 2.0 millibar (mbar). The addition of the composition (S) was carried out at the inlet of the second polymerization reactor (107) [00108] The composition (S) once prepared was heated so that the composition (S) was in the molten form. The molten composition (S) was maintained at a temperature between 85-90 °C while being added into the polymerization reactor at specified dozing rate using a diaphragm pump [capacity 0.05 - 5.0 kg/h] .

[00109] The melt polycarbonate resin obtained from the second polymerization reactor (107) was further fed to an extruder (109), which provided for the addition of additives such as anti-oxidants, light stabilizers, flame retardants, colorants, quenchers to the polycarbonate resin. The extrudate (111) obtained was sent to a pelletizer (112), subsequently melt polycarbonate resin pellets were obtained. The melt polycarbonate resin pellets were evaluated to determine the weight average molecular weight, the content of linear Fries product, total Fries product and residual Bisphenol A content, using the methods described in Table 2.

[00110] The results are provided in Table 3. The melt polycarbonate pellets were subsequently molded to obtain polycarbonate plaques. The polycarbonate plaques were subjected to thermal ageing and yellowness index (YI) was measured. The results are provided in Table 3.

[00111] Preparation of composition (S): Prior to addition, the composition (S) was independently prepared by the following procedure: PMSC was melted at 100 °C for 25-45 mins, in a stainless steel tank, n-butyl tosylate (BuTos) was added and the composition was homogeneously dispersed using a re-circulation pump.

[00112] Comparative samples: For the polycarbonate resin (CE1), the process followed was identical to the process used for preparing the inventive sample IE, except that composition (S) was not added. For the polycarbonate resin (CE2), the process followed was identical to the process used for preparing the inventive sample IE, except that only Phenyl methyl salicylyl carbonate (PMSC) was added without using n-butyl tosylate (BuTos).

[00113] The results obtained are reported below:

Table 3

[00114] Results and Conclusion: From the results provided under Table 3, it is observed that the inventive sample IE demonstrated improved color stability over that of polycarbonate plaques CE1 and CE2 even after being subjected to thermal aging of 2000 hours. For example, the yellowness index (YI) of the sample IE was at least 15% (5.53 versus 6.56) lower than that of sample CE1 and at least 8% (5.53 versus 6.02) lower than that of sample CE2. In other words, the extent of de-coloration for the sample IE was lower than that of the sample CE1 and CE2 as indicated by the values provided.

[00115] Further the sample IE has a lower content of residual Bisphenol A compared to the samples CE1 and CE2, which is particularly advantageous from a regulatory and health perspective. The lower content of linear Fries product and total Fries product for the sample IE is indicative of the polycarbonate sample having improved properties of color stability, lower residual Bisphenol A content and higher End-cap% over that of CE1 and CE2.

[00116] The results shown in Table 3 are surprising especially when comparing the properties of sample IE with sample CE2, indicating that a composition comprising a purposeful combination of PMSC with BuTos when added to a process of producing melt polycarbonate, results in a polycarbonate resin having an improved set of properties as described in this disclosure. Compounds such as PMSC are known to reduce Fries product as described in the US patent US6590068B2. However, as observed from Table 3, the use of a composition of PMSC and BuTos provided a melt polycarbonate resin IE with further improved properties over a melt polycarbonate resin produced by adding only PMSC (CE2).

[00117] Further the results are even more surprising considering BuTos is often used as a quencher compound to deactivate traces of residual catalyst present in the melt polycarbonate resin and prevent adverse molecular weight build-up. However, the sample ‘IE’ retained its molecular weight despite the addition of composition (S) comprising BuTos, during the production of the melt polycarbonate resin (IE).

Example II

[00118] Purpose: Demonstrate the improved thermal stability of the composition (S) under thermal conditions.

[00119] Process of preparing the Composition (S) comprising n-butyl tosylate (BuTos) and Phenyl methyl salicylyl carbonate (PMSC): 100 g of PMSC was dissolved in 200 g of methylene chloride in a glass round bottom flask. To it were added n-butyl tosylate (BuTos) solution in methylene chloride such that the resulting concentration of Butyl tosylate is 500 parts per million in PMSC. The methylene chloride was stripped under reduced pressure in the Heidolph rotary evaporator. The resultant material was dried in an oven at 60 °C for 4 hours. The presence of BuTos in PMSC was confirmed by Gas Chromatography. A second sample was prepared where the resulting concentration of Butyl tosylate was maintained at 111 parts per million in PMSC

[00120] Process of conducting thermal stability analysis of Composition (S): Test samples were charged into previous passivated closed stainless-steel reactors. The reactors were heated to a temperature of 300 °C using a thermal heater with provision of thermocouple to measure the temperature. Samples were heated for 20 minutes and the reactor was cooled by switching-off the heater. The final composition was analyzed using GC and the results are provided in the table below:

Table 4

[00121] From Table 4, it is observed that the composition (S) comprising a stabilized mixture of PMSC and BuTos had improved thermal stability where the extent of degradation of PMSC to generate species such as diphenyl carbonate (DPC) and bis(methyl salicyl) carbonate (BMSC) was observed to be significantly reduced. This is particularly advantageous as species such as BMSC and DPC may deteriorate the process of production of the melt polycarbonate and in addition adversely affect the properties of the resultant melt polycarbonate once produced.

[00122] Further, it was observed that with a lower BuTos content (111 ppm versus 550ppm), the extent of stabilization was lowered.

Claims

1. A composition (S), comprising:

• at least one compound (A) represented by formula (I): wherein ‘G’ is a substituent selected from the group consisting of R¹(C=O)-, halogen group, cyano group, and nitro group, wherein the substituent R¹ is independently selected from the group consisting of optionally substituted alkoxy group, optionally substituted phenoxy group, optionally substituted benzyloxy group, and optionally substituted phenyl group; and wherein the substituent R² is independently selected from the group consisting of optionally substituted C1-C40 alkyl group, optionally substituted Ce-Cso aryl group, optionally substituted C7-C30 aralkyl group, and optionally substituted C6-C30 aryloxy group; and

> at least one compound (B) selected from the group consisting of organosulfonic acid, organosulfonic acid ester, phosphoric acid, gluconic acid, gluconic acid based salts and esters, ethylene diamine tetra-acetic acid and salts, citric acid, citric acid based salts and esters, and any combination thereof; preferably compound (B) is selected from the group consisting of aryl sulfonic acid, aryl sulfonic acid ester, bridged aryl sulfonic acid ester and combination thereof; • wherein the compound (B) is present in an amount from 150.0 parts per million by weight to 1000.0 parts per million by weight, with regard to the total weight of the compound (A); and

• wherein the compound (A) is asymmetrical relative to a longitudinal axis passing through the carbon atom attached to the substituent ‘R²’ .

2. The composition (S) of claim 1, wherein the compound (A) is at least one compound selected from the group consisting of:

any combination thereof, wherein ‘X’ is a halogen selected from chlorine, bromine, iodine, and fluorine.

3. The composition (S) according to any one of claims 1-2, wherein the compound (B) comprises or consists of n-butyl tosylate.

4. The composition (S) according to any one of claims 1-3, wherein

• the compound (A) is represented by the formula:

• the compound (B) comprises or consists of n-butyl tosylate and is present in an amount from 150.0 parts per million by weight to 1000.0 parts per million by weight, with regard to the total weight of the compound (A).

5. A process for preparing a melt polycarbonate resin comprising the step of reacting one or more dihydric phenol compound with one or more diaryl carbonate compound in molten state and in at least two reactors positioned in series, wherein the process comprises the step of adding the composition (S) according to any one or more of claims 1-4, prior to the melt polycarbonate resin leaving a final reactor.

6. The process of claim 5, wherein the diaryl carbonate is selected from the group consisting of diphenyl carbonate, ditolyl carbonate, halogen substituted diphenyl carbonate, m-cresyl carbonate, and dinaphthyl carbonate and combination thereof; and/or wherein the dihydric phenol is selected from the group consisting of bis(4-hydroxyphenyl)methane; l,l-bis(4- hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis(4- hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4- hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-l-methylphenyl)propane, 1, 1 -bis(4- hydroxy-t-butylphenyl) propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, l,l-(4- hydroxyphenyl) cyclopentane, 1 , 1 -bis(4-hydroxyphenyl)cyclohexane, 4,4'- dihydroxydiphenyl ether, 4,4 'dihydroxy-3 , 3 '-dimethylphenyl ether, 4,4'- dihydroxydiphenyl sulphide, 4, 4'-dihydroxy-3, 3 '-dimethyl diphenyl sulfide, 4,4'- dihydroxydiphenyl sulfoxide, 4, 4 '-dihydroxy-3, 3 '-dimethyl diphenyl sulfoxide, 4,4'- dihydroxydiphenyl sulfone, 4, 4 '-dihydroxy-3, 3 '-dimethyl diphenyl sulfone and combination thereof.

7. The process according to any one of claims 5-6: • wherein the step of reacting the one or more dihydric phenol compound with one or more diaryl carbonate compound is carried out in at least one oligomerization reactor and at least one polymerization reactor; and

• wherein the step of adding the composition (S) is carried out after the reaction in the at least one oligomerization reactor and before or during the reaction in the at least one polymerization reactor.

8. The process according to any one of claims 5-7, wherein the composition (S) is added in an amount from 0.1 wt.% to 10.0 wt.%, with regard to the total weight of the melt polycarbonate resin.

9. The process according to any one of claims 5-8, wherein the composition (S) is added under molten state, preferably wherein the composition (S) is maintained at any temperature of at least 70.0 °C and at most 150 °C while being added.

10. The process according to any one of claims 5-9, wherein the composition (S) is added to an oligomeric reaction product of one or more dihydric phenol compound and one or more diaryl carbonate compound after such an oligomeric reaction product has reached a weight average molecular weight of at least 10,000 g/mol as determined with gel permeation chromatography using polystyrene standard in accordance with ASTM D5296-11.

11. The process according to any one of claims 5-10, wherein the composition (S) is added to an oligomeric reaction product of one or more dihydric phenol compound and one or more diaryl carbonate compound, prior to such an oligomeric reaction product being introduced in the final reactor.

12. The process according to any one of claims 5-11, wherein the process further comprises:

13. A melt polycarbonate resin obtainable by the process according to any one of claims 5-12.

14. The melt polycarbonate resin of claim 13 has at least one of: • a weight average molecular weight from 25,000 g/mol to 70,000 g/mol determined with gel permeation chromatography using polystyrene standard in accordance with ASTM D5296-11; and/or

15. Use of the composition (S) according to any one of the claims 1-4 for reducing reactive byproduct in a melt polycarbonate resin, wherein the reactive by-product is at least one of linear Fries product, unreacted dihydric phenol, unreacted monohydric phenol and combination thereof.