WO2009053998A2 - Catalyst for the production of polyester - Google Patents
Catalyst for the production of polyester Download PDFInfo
- Publication number
- WO2009053998A2 WO2009053998A2 PCT/IN2008/000456 IN2008000456W WO2009053998A2 WO 2009053998 A2 WO2009053998 A2 WO 2009053998A2 IN 2008000456 W IN2008000456 W IN 2008000456W WO 2009053998 A2 WO2009053998 A2 WO 2009053998A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- polyester
- catalyst system
- range
- ppm
- antimony
- Prior art date
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- 239000003054 catalyst Substances 0.000 title claims abstract description 69
- 229920000728 polyester Polymers 0.000 title claims abstract description 63
- 238000004519 manufacturing process Methods 0.000 title description 7
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 24
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 19
- 229910052787 antimony Inorganic materials 0.000 claims abstract description 18
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 claims abstract description 18
- -1 alkali metal salt Chemical class 0.000 claims abstract description 15
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 14
- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000007787 solid Substances 0.000 claims description 15
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 13
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 claims description 12
- 150000002148 esters Chemical class 0.000 claims description 8
- 229920001225 polyester resin Polymers 0.000 claims description 8
- 239000004645 polyester resin Substances 0.000 claims description 8
- 229920005862 polyol Polymers 0.000 claims description 8
- 150000003077 polyols Chemical class 0.000 claims description 8
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 claims description 7
- 150000001875 compounds Chemical class 0.000 claims description 6
- 239000000835 fiber Substances 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 4
- 150000001733 carboxylic acid esters Chemical class 0.000 claims description 4
- 230000000379 polymerizing effect Effects 0.000 claims description 3
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 claims description 3
- 159000000000 sodium salts Chemical group 0.000 claims description 2
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 52
- 238000006116 polymerization reaction Methods 0.000 description 28
- 230000000694 effects Effects 0.000 description 18
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- 238000005886 esterification reaction Methods 0.000 description 10
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 10
- KVCGISUBCHHTDD-UHFFFAOYSA-M sodium;4-methylbenzenesulfonate Chemical compound [Na+].CC1=CC=C(S([O-])(=O)=O)C=C1 KVCGISUBCHHTDD-UHFFFAOYSA-M 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 9
- 229910001873 dinitrogen Inorganic materials 0.000 description 8
- 239000002245 particle Substances 0.000 description 8
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 7
- 238000006068 polycondensation reaction Methods 0.000 description 7
- 229920000642 polymer Polymers 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 150000001463 antimony compounds Chemical class 0.000 description 5
- 239000000155 melt Substances 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 4
- 239000011541 reaction mixture Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000000178 monomer Substances 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 229940011182 cobalt acetate Drugs 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000032050 esterification Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- CKFGINPQOCXMAZ-UHFFFAOYSA-N methanediol Chemical compound OCO CKFGINPQOCXMAZ-UHFFFAOYSA-N 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 239000003017 thermal stabilizer Substances 0.000 description 2
- NEQFBGHQPUXOFH-UHFFFAOYSA-N 4-(4-carboxyphenyl)benzoic acid Chemical compound C1=CC(C(=O)O)=CC=C1C1=CC=C(C(O)=O)C=C1 NEQFBGHQPUXOFH-UHFFFAOYSA-N 0.000 description 1
- 229920001634 Copolyester Polymers 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229940058905 antimony compound for treatment of leishmaniasis and trypanosomiasis Drugs 0.000 description 1
- FAWGZAFXDJGWBB-UHFFFAOYSA-N antimony(3+) Chemical class [Sb+3] FAWGZAFXDJGWBB-UHFFFAOYSA-N 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 238000000071 blow moulding Methods 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- PMMYEEVYMWASQN-IMJSIDKUSA-N cis-4-Hydroxy-L-proline Chemical compound O[C@@H]1CN[C@H](C(O)=O)C1 PMMYEEVYMWASQN-IMJSIDKUSA-N 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 150000001991 dicarboxylic acids Chemical class 0.000 description 1
- SZXQTJUDPRGNJN-UHFFFAOYSA-N dipropylene glycol Chemical compound OCCCOCCCO SZXQTJUDPRGNJN-UHFFFAOYSA-N 0.000 description 1
- 235000019256 formaldehyde Nutrition 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- KYTZHLUVELPASH-UHFFFAOYSA-N naphthalene-1,2-dicarboxylic acid Chemical compound C1=CC=CC2=C(C(O)=O)C(C(=O)O)=CC=C21 KYTZHLUVELPASH-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229920006280 packaging film Polymers 0.000 description 1
- 239000012785 packaging film Substances 0.000 description 1
- 230000037048 polymerization activity Effects 0.000 description 1
- 239000002685 polymerization catalyst Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 229920001059 synthetic polymer Polymers 0.000 description 1
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/16—Dicarboxylic acids and dihydroxy compounds
- C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
- C08G63/181—Acids containing aromatic rings
- C08G63/183—Terephthalic acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
- C08G63/82—Preparation processes characterised by the catalyst used
- C08G63/85—Germanium, tin, lead, arsenic, antimony, bismuth, titanium, zirconium, hafnium, vanadium, niobium, tantalum, or compounds thereof
- C08G63/86—Germanium, antimony, or compounds thereof
- C08G63/866—Antimony or compounds thereof
Definitions
- the invention relates to a catalyst system comprising an antimony compound and an alkali metal salt of paratoluene sulphonic acid for the synthesis of polyester resins.
- the invention also relates to the process for polyester synthesis, to the polyester and to the articles prepared thereof .
- Polyesters such as polyethylene terephthalate (PET) are used in large quantities in the manufacture of textile fibers, packaging films and containers. Typically, such polyesters are synthesized by a catalysed two stage reaction. In the first stage, esterification reaction is carried out between a dicarboxylic acid and a polyol. The esterification reaction is followed by melt polymerization wherein the ester formed in the first stage undergoes polycondensation resulting in a polyester. Often the polyester obtained after melt polymerisation is further subjected to solid state polymerisation.
- PET polyethylene terephthalate
- the invention provides a catalyst system comprising an antimony compound and an alkali metal salt of paratoluene sulphonic acid for the synthesis of polyester.
- polyester as used herein, is intended to include “copolyesters” and is understood to mean a synthetic polymer prepared by the polycondensation of one or more difunctional carboxylic acids with one or more difunctional hydroxyl compounds.
- low viscosity polyester is intended to mean polyester having intrinsic viscosity in the range of 0.20 dl/g to 0.65 dl/g.
- the invention provides a catalyst system for polyester synthesis, the catalyst system comprising at least 50 ppm of antimony wherein the antimony is present in the form of a compound and at least 10 ppm of an alkali metal salt of paratoluene sulphonic acid.
- the invention provides a catalyst system for polyester synthesis comprising antimony present in an amount ranging from 50 to 1500 ppm and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm wherein the antimony is present in the form of a compound.
- the invention provides a catalyst system for polyester synthesis comprising antimony present in an amount ranging from 50 to 1500 ppm and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm wherein the antimony is present in the form of a compound and the alkali metal salt is a sodium salt or a potassium salt.
- the invention provides a process for synthesis of a polyester resin in the presence of a catalyst system comprising antimony present in an amount ranging from 50 to 1500 ppm, the antimony being present in the form of a compound and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm, the process comprising esterifying at least one organic dicarboxylic acid with a polyol at a temperature in the range of 250°C to 290 0 C to obtain a carboxylic acid ester and melt polymerizing the acid ester at temperature in the range of 260°C to 300°C to obtain a low viscosity polyester.
- a catalyst system comprising antimony present in an amount ranging from 50 to 1500 ppm, the antimony being present in the form of a compound and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm
- the process comprising esterifying at least one organic dicarboxy
- the invention provides a polyester having an intrinsic viscosity in the range of 0.20 to 0.45 dl/g
- the invention provides a polyester having an intrinsic viscosity in the range of 0.45 to 0.65 dl/g.
- the invention provides a polyester having an intrinsic viscosity in the range of 0.70 to 1.20 dl/g.
- the invention provides films, fibers, filaments and yarns prepared from the polyester.
- the invention provides a process for synthesis of a polyester resin in the presence of catalyst system comprising antimony present in an amount ranging from 50 to 1500 ppm wherein the antimony is present in the form of a compound and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm, the process comprising esterifying at least one dicarboxylic acid with a polyol at a temperature in the range of 250°C to 290°C to obtain a carboxylic acid ester, melt polymerizing the acid ester at temperature in the range of 26O 0 C to 300°C to obtain a low viscosity polyester and reacting the low viscosity polyester in the solid state at a temperature in the range of 200 0 C to 24O 0 C to form a polyester having intrinsic viscosity in the range of 0.70 to 1.20 dl/g
- the invention provides shaped articles prepared from the polyester.
- the invention provides a catalyst system comprising an antimony compound and an alkali metal salt of paratoluene sulphonic acid.
- the total metal content of the catalyst system is in the range of 10 ppm to 1000 ppm.
- the catalyst system has a metal content in the range of 100 to 400 ppm.
- an antimony compound in combination with a sodium or potassium salt of the paratoluene sulphonic acid is used in the catalyst system.
- the invention also provides a process for synthesis of polyester resins in the presence of the catalyst system. Usually, the process is carried out in two stages resulting in a low molecular weight polyester. In the first stage an organic dicarboxylic acid is reacted with polyol at around 250°celsius to 290°celsius to obtain an acid ester.
- the organic dicarboxylic acid used in the esterification stage is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic or any suitable dicarboxylic acids or derivatives thereof.
- the polyol used is selected from monoethylene glycol, diethylene glycol, Methylene glycol, propylene glycol, dipropylene glycol, butylenes glycol, 1 ,4-cyclohexane diol or any other suitable polyol.
- the first stage reaction results in carboxylic acid ester which is melt polymerised at around 260°C to 300°C to obtain a low viscosity polyester.
- the intrinsic viscosity of the polyester formed after melt polymerization is in the range of 0.20 dl/g to 0.65 dl/g.
- the melt polymerization yields polyester having different intrinsic viscosities.
- a polyester having intrinsic viscosity of around 0.60 dl/g is obtained.
- a polyester having intrinsic viscosity of around 0.26 dl/g is obtained.
- the low viscosity polyesters can be crystalline, semicrystalline or amorphous.
- the low viscosity polyester is either used directly in the manufacture of films, fibers or filaments or is further polymersied in the solid state to form higher molecular weight polyester. After melt polymerization the low viscosity polyester is either drained and cut into granular form or is passed through an orifice to form droplets on a steel conveyor belt of a particle former.
- the catalyst system is added at any stage during esterification or melt polymerization but before particle former stage or before solid state polymerization.
- the solid state polymerization is catalysed by the catalyst system used in the melt polymerization stage.
- the solid state polymerization usually results in polyester having intrinsic viscosity in the range of 0.70 to 1.20 dl/g.
- the polyester may be linear or branched and may be a homo-polyester and may contain co-monomers upto 10 wt%.
- the catalyst system used in the process of the invention can be used either in the supported or unsupported form.
- the polyester resins synthesized by the process of the invention can be used for the manufacture of articles such as preforms, molded parts, containers, fibers or filaments, films or sheets or technical yarn in various sizes and shapes.
- the polymerization process can be a continuous process or a batch process.
- the resin can also be combined with additives to impart specific functional characteristics.
- the invention is further illustrated by way of the following examples. In the examples, the melt polymerization synthesis of polyester resin having intrinsic viscosity around 0.26 dl/g is carried out at atmospheric pressure under nitrogen flow. Consequently, the reactivity or the catalyst activity is measured in terms of the amount of nitrogen gas that flows into the reactor at a fixed nitrogen gas temperature.
- the catalyst activity and reactivity during the synthesis of polyester resins of higher viscosity is measured in terms of the residence time.
- the residence time is measured as the time required to obtain a polyester of desired intrinsic viscosity from the beginning of polymerisation reaction Example 1:
- polyester having intrinsic viscosity of around 0.60 dl/g using the catalyst system comprising antimony trioxide and sodium para toluene sulphonate
- the oligomer obtained was then subjected to polycondensation in the presence of Cobalt acetate based on 25 ppm cobalt and phosphoric acid based on 25 ppm as phosphorous at temperature of 285 0 C to obtain the prepolymer having IV up to 0.60 dl/g. After achieving desired prepolymer IV, the polyester was drained and cut in a granular form for further processing.
- Example 2 Example 2:
- polyester having intrinsic viscosity of around 0.26 dl/g using the catalyst system comprising antimony trioxide and sodium para toluene sulphonate
- terephthalic acid and monoethylene glycol were charged in 1 :2 molar ratio.
- 2 wt % Isophthalic acid and 1.5 wt % diethyl ene glycol (DEG) were added.
- the esterification reaction was carried out at 280°C.
- Sodium para-toluene sulfonate having 200ppm based on sodium was added at the end of esterification reaction.
- the oligomer obtained was polymerized at 290°C to raise the IV up to 0.26 dl/g in presence of about 290ppm of antimony as a catalyst and 15 ppm phosphorous as a thermal stabilizer.
- a static mixer was put after every injection nozzle for adding any suitable additive, co-monomer for better dispersion.
- the low IV prepolymer melt was then passed through the 1.5 mm diameter orifice to form droplets on a continuous moving steel belt of particle former. These droplets were then crystallized on the particle former maintained at a temperature between 110 to 16O 0 C and then collected for carrying out solid-state polymerization.
- Crystalline prepolymer having IV of 0.26 dl/g obtained in the example 2 and 4 was solid-state polymerized under inert atmosphere to raise the IV up to 0.76 dl/g.
- the solid-state polymerization reaction was carried out at 235°C of nitrogen gas temperature. After achieving desired IV, the reaction terminated and polymer drained and collected.
- Example 7 Manufacture of performs and bottles
- Resin produced by SSP process was used for producing preforms using 2 cavity Arburg injection moulding machine (Model: Allrounder 420C). Before moulding, resins were dried for 6 hrs at 175°C in a dryer. Preform weight was 48g. Processing temperatures were in the range of 280 - 300°C and the cycle time was 34.5 seconds. These preforms were then used for producing bottles having volume of 1.5L. Bottles were produced using SIDEL SBOl single cavity blow moulding machine. Blowing temperature was maintained at 105 0 C.
- melt polymerization (polycondensation) activity of the catalyst system of the invention is compared with antimony trioxide alone as catalyst in Table 1.
- Table 1 Comparison of activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide alone as catalyst during polycondensation of ester to achieve an intrinsic viscosity (IV) of 0.60 dl/g
- Table 2 Comparison of activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide alone as catalyst during polycondensation of ester to achieve an intrinsic viscosity of 0.26 dl/g
- Table 4 Comparison of activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide catalyst during solid state polymerization of low viscosity polymers formed in examples 2 and 4
- Polyester of comparable intrinsic viscosity (0.767 dl/g) is obtained at a lower residence time (12 hours) by using the catalyst system of the invention.
- the catalyst system of the invention exhibits improved activity that enables synthesis of polyester with high productivity and throughput.
- the synthesis is more efficient and cost effective.
- the reaction temperatures can be kept low to avoid unwanted side reactions.
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Catalysts (AREA)
- Polyesters Or Polycarbonates (AREA)
Abstract
The invention relates to a catalyst system for polyester synthesis, the catalyst system comprising at least 10 ppm of an alkali metal salt of paratoluene sulphonic acid and at least 50 ppm of antimony. The invention also relates to a process for polyester synthesis, to the polyester and to the articles prepared thereof.
Description
Catalyst for the production of polyester TECHNICAL FIELD OF THE INVENTION: The invention relates to a catalyst system comprising an antimony compound and an alkali metal salt of paratoluene sulphonic acid for the synthesis of polyester resins. The invention also relates to the process for polyester synthesis, to the polyester and to the articles prepared thereof .
BACKGROUND: Polyesters such as polyethylene terephthalate (PET) are used in large quantities in the manufacture of textile fibers, packaging films and containers. Typically, such polyesters are synthesized by a catalysed two stage reaction. In the first stage, esterification reaction is carried out between a dicarboxylic acid and a polyol. The esterification reaction is followed by melt polymerization wherein the ester formed in the first stage undergoes polycondensation resulting in a polyester. Often the polyester obtained after melt polymerisation is further subjected to solid state polymerisation.
Conventionally, trivalent antimony compounds like antimony trioxide and its alcohol derivatives are used as ester polymerization catalysts. However, when used alone as the catalyst, the activity for polyester synthesis of antimony compounds is rather limited (Ben Duh, Polymer 43 (2002) 3147-3154). Lower catalyst activity would require longer residence times for synthesis of resins of desired molecular weight. This in turn affects the productivity, throughput and results in high production cost. There is a need for a catalyst system having improved activity for the synthesis of polyesters.
DETAILED DESCRIPTION:
Accordingly the invention provides a catalyst system comprising an antimony compound and an alkali metal salt of paratoluene sulphonic acid for the synthesis of polyester.
When used throughout this specification, the following terms have the meanings indicated:
The term "polyester", as used herein, is intended to include "copolyesters" and is understood to mean a synthetic polymer prepared by the polycondensation of one or more difunctional carboxylic acids with one or more difunctional hydroxyl compounds.
The term "low viscosity polyester", as used herein, is intended to mean polyester having intrinsic viscosity in the range of 0.20 dl/g to 0.65 dl/g.
In one embodiment the invention provides a catalyst system for polyester synthesis, the catalyst system comprising at least 50 ppm of antimony wherein the antimony is present in the form of a compound and at least 10 ppm of an alkali metal salt of paratoluene sulphonic acid.
In another embodiment, the invention provides a catalyst system for polyester synthesis comprising antimony present in an amount ranging from 50 to 1500 ppm and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm wherein the antimony is present in the form of a compound.
In another embodiment, the invention provides a catalyst system for polyester synthesis comprising antimony present in an amount ranging from 50 to 1500 ppm and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm wherein the
antimony is present in the form of a compound and the alkali metal salt is a sodium salt or a potassium salt.
In another embodiment, the invention provides a process for synthesis of a polyester resin in the presence of a catalyst system comprising antimony present in an amount ranging from 50 to 1500 ppm, the antimony being present in the form of a compound and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm, the process comprising esterifying at least one organic dicarboxylic acid with a polyol at a temperature in the range of 250°C to 2900C to obtain a carboxylic acid ester and melt polymerizing the acid ester at temperature in the range of 260°C to 300°C to obtain a low viscosity polyester.
In another embodiment the invention provides a polyester having an intrinsic viscosity in the range of 0.20 to 0.45 dl/g
In another embodiment the invention provides a polyester having an intrinsic viscosity in the range of 0.45 to 0.65 dl/g.
In another embodiment the invention provides a polyester having an intrinsic viscosity in the range of 0.70 to 1.20 dl/g.
In yet another embodiment the invention provides films, fibers, filaments and yarns prepared from the polyester.
In a further embodiment the invention provides a process for synthesis of a polyester resin in the presence of catalyst system comprising antimony present in an amount ranging from 50 to 1500
ppm wherein the antimony is present in the form of a compound and an alkali metal salt of paratoluene sulphonic acid present in an amount ranging from 10 to 500 ppm, the process comprising esterifying at least one dicarboxylic acid with a polyol at a temperature in the range of 250°C to 290°C to obtain a carboxylic acid ester, melt polymerizing the acid ester at temperature in the range of 26O0C to 300°C to obtain a low viscosity polyester and reacting the low viscosity polyester in the solid state at a temperature in the range of 2000C to 24O0C to form a polyester having intrinsic viscosity in the range of 0.70 to 1.20 dl/g
In a still further embodiment the invention provides shaped articles prepared from the polyester.
The invention provides a catalyst system comprising an antimony compound and an alkali metal salt of paratoluene sulphonic acid. The total metal content of the catalyst system is in the range of 10 ppm to 1000 ppm. Advantageously the catalyst system has a metal content in the range of 100 to 400 ppm. Typically, an antimony compound in combination with a sodium or potassium salt of the paratoluene sulphonic acid is used in the catalyst system.
The invention also provides a process for synthesis of polyester resins in the presence of the catalyst system. Usually, the process is carried out in two stages resulting in a low molecular weight polyester. In the first stage an organic dicarboxylic acid is reacted with polyol at around 250°celsius to 290°celsius to obtain an acid ester. The organic dicarboxylic acid used in the esterification stage is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic or any suitable dicarboxylic acids or derivatives thereof. The polyol used is selected from monoethylene glycol, diethylene glycol, Methylene glycol, propylene glycol, dipropylene glycol, butylenes glycol, 1 ,4-cyclohexane diol or any other suitable polyol. The first stage reaction results in carboxylic acid ester which is melt
polymerised at around 260°C to 300°C to obtain a low viscosity polyester. Typically the intrinsic viscosity of the polyester formed after melt polymerization is in the range of 0.20 dl/g to 0.65 dl/g.
Depending upon the process conditions, the melt polymerization yields polyester having different intrinsic viscosities. In one aspect of the invention, a polyester having intrinsic viscosity of around 0.60 dl/g is obtained. In another aspect of the invention, a polyester having intrinsic viscosity of around 0.26 dl/g is obtained. The low viscosity polyesters can be crystalline, semicrystalline or amorphous. The low viscosity polyester is either used directly in the manufacture of films, fibers or filaments or is further polymersied in the solid state to form higher molecular weight polyester. After melt polymerization the low viscosity polyester is either drained and cut into granular form or is passed through an orifice to form droplets on a steel conveyor belt of a particle former. The catalyst system is added at any stage during esterification or melt polymerization but before particle former stage or before solid state polymerization. The solid state polymerization is catalysed by the catalyst system used in the melt polymerization stage. The solid state polymerization usually results in polyester having intrinsic viscosity in the range of 0.70 to 1.20 dl/g. The polyester may be linear or branched and may be a homo-polyester and may contain co-monomers upto 10 wt%.
The catalyst system used in the process of the invention can be used either in the supported or unsupported form. The polyester resins synthesized by the process of the invention can be used for the manufacture of articles such as preforms, molded parts, containers, fibers or filaments, films or sheets or technical yarn in various sizes and shapes. The polymerization process can be a continuous process or a batch process. The resin can also be combined with additives to impart specific functional characteristics.
The invention is further illustrated by way of the following examples. In the examples, the melt polymerization synthesis of polyester resin having intrinsic viscosity around 0.26 dl/g is carried out at atmospheric pressure under nitrogen flow. Consequently, the reactivity or the catalyst activity is measured in terms of the amount of nitrogen gas that flows into the reactor at a fixed nitrogen gas temperature. The lesser the requirement of the nitrogen gas, the higher the catalyst activity and reactivity. The catalyst activity and reactivity during the synthesis of polyester resins of higher viscosity is measured in terms of the residence time. The lesser the residence time, the higher the activity. The residence time is measured as the time required to obtain a polyester of desired intrinsic viscosity from the beginning of polymerisation reaction Example 1:
Synthesis of polyester having intrinsic viscosity of around 0.60 dl/g using the catalyst system comprising antimony trioxide and sodium para toluene sulphonate
Purified terephthalic acid and monoethylene glycol (MEG) were charged in 1:2 molar ratio. To the reaction mixture, 2 wt % Isophthalic acid, antimony trioxide catalyst containing 290 ppm antimony and 25 ppm of sodium hydroxide was added. The esterification reaction was carried out at 2560C. Sodium para-toluene sulfonate based on 300ppm as sodium was added at the end of esterification reaction. The oligomer obtained was then subjected to polycondensation in the presence of Cobalt acetate based on 25 ppm cobalt and phosphoric acid based on 25 ppm as phosphorous at temperature of 2850C to obtain the prepolymer having IV up to 0.60 dl/g. After achieving desired prepolymer IV, the polyester was drained and cut in a granular form for further processing.
Example 2:
Synthesis of polyester having intrinsic viscosity of around 0.26 dl/g using the catalyst system comprising antimony trioxide and sodium para toluene sulphonate
Purified terephthalic acid and monoethylene glycol (MEG) were charged in 1 :2 molar ratio. To the reaction mixture, 2 wt % Isophthalic acid and 1.5 wt % diethyl ene glycol (DEG) were added. The esterification reaction was carried out at 280°C. Sodium para-toluene sulfonate having 200ppm based on sodium was added at the end of esterification reaction. The oligomer obtained was polymerized at 290°C to raise the IV up to 0.26 dl/g in presence of about 290ppm of antimony as a catalyst and 15 ppm phosphorous as a thermal stabilizer. A static mixer was put after every injection nozzle for adding any suitable additive, co-monomer for better dispersion. The low IV prepolymer melt was then passed through the 1.5 mm diameter orifice to form droplets on a continuous moving steel belt of particle former. These droplets were then crystallized on the particle former maintained at a temperature between 110 to 16O0C and then collected for carrying out solid-state polymerization.
Example 3:
Synthesis of polyester having intrinsic viscosity of around 0.60 dl/g using antimony trioxide catalyst
Purified terephthalic acid and monoethylene glycol (MEG) were charged in 1 :2 molar ratio. To the above reaction mixture, 2 wt % Isophthalic acid, antimony trioxide catalyst containing 290 ppm antimony and 25 ppm of sodium hydroxide was added. The esterification reaction was carried out at 256°C. The oligomer obtained was then subjected to polycondensation in the presence of Cobalt acetate containing 25 ppm of cobalt and phosphoric acid containing 25 ppm of
phosphorous at temperature of 2850C to obtained a prepolymer having IV up to 0.60 dl/g. This prepolymer was considered as "Control" for the prepolymer prepared according to Example 1. After achieving desired prepolymer IV, the polyester was drained and cut in a granular form for further processing.
Example 4:
Synthesis of polyester having intrinsic viscosity of around 0.26 dl/g using antimony trioxide catalyst
Purified terephthalic acid and monoethylene glycol were charged in 1:2 molar ratio. To the above reaction mixture, 1.5wt % Isophthalic acid and 1.5 wt % diethylene glycol were added. The esterification reaction was carried out at 280°C. The oligomer obtained was polymerised at 290°C to raise the IV up to 0.26 dl/g. About 290ppm of antimony was added as a catalyst and 15 ppm Phosphorous was added as a thermal stabilizer. A static mixer was put after every injection nozzle for adding any suitable additive, co-monomer for better dispersion. The low IV prepolymer melt was then passed through the 1.5 mm diameter orifice to form droplets on a continuous moving steel belt of particle former. These droplets were then crystallized on the particle former maintained at a temperature between 110 to 16O0C and then collected for carrying out solid-state polymerization. These prepolymer particles were considered as "Control" for the prepolymer particles prepared according to Example 2.
Example 5:
Comparative study of the activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide alone as catalyst for solid state polymerization of low viscosity polymer formed in examples 1 and 3
Amorphous chips obtained in the example 1 & 3 were precrystallized in a tumbler dryer at a temperature of usually 100 to 200°C for a period of two hours. These precrystallized chips desirably have 20 to 40 % crystallinity. These chips were then used as a precursor of solid-state polymerization. 20kg Crystallized prepolymer chips were subjected to solid-state polymerization at nitrogen gas temperature of 2100C. Samples were drawn every hour to monitor IV rise for each recipe. After achieving desired IV, the reaction was terminated and polymer drained and collected.
Example 6:
Comparative study of the activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide alone as catalyst during solid state polymerization of low viscosity polymer formed in examples 2 and 4
Crystalline prepolymer having IV of 0.26 dl/g obtained in the example 2 and 4, was solid-state polymerized under inert atmosphere to raise the IV up to 0.76 dl/g. The solid-state polymerization reaction was carried out at 235°C of nitrogen gas temperature. After achieving desired IV, the reaction terminated and polymer drained and collected.
Example 7: Manufacture of performs and bottles
Resin produced by SSP process was used for producing preforms using 2 cavity Arburg injection moulding machine (Model: Allrounder 420C). Before moulding, resins were dried for 6 hrs at 175°C in a dryer. Preform weight was 48g. Processing temperatures were in the range of 280 - 300°C and the cycle time was 34.5 seconds. These preforms were then used for producing bottles
having volume of 1.5L. Bottles were produced using SIDEL SBOl single cavity blow moulding machine. Blowing temperature was maintained at 1050C.
The melt polymerization (polycondensation) activity of the catalyst system of the invention is compared with antimony trioxide alone as catalyst in Table 1.
Table 1: Comparison of activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide alone as catalyst during polycondensation of ester to achieve an intrinsic viscosity (IV) of 0.60 dl/g
From table 1, it is clear that the time required for melt polymerization to achieve a target IV of 0.60 dl/g is substantially less for the catalyst system of the invention (catalyst system of Example 1). In other words the melt polymerization rate is significantly improved with the catalyst system of the invention.
Table 2 compares the activity of the catalyst system of the invention with antimony trioxide alone as catalyst during melt polymerization to obtain polyester having intrinsic viscosity of 0.26 dl/g.
Table 2: Comparison of activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide alone as catalyst during polycondensation of ester to achieve an intrinsic viscosity of 0.26 dl/g
From table 2 it is clear that in the experiment (experiment No 1) using the catalyst system of the invention, the nitrogen gas flow in the column reactor is lowered as compared to the nitrogen gas flow in the reactor of experiment No 2 that uses antimony trioxide alone as catalyst, The lowering of nitrogen gas flow in the reactor is indicative of the increase in solid state polymerization rate.
In table 3, the solid state polymerization activity of the reaction using catalyst system of the invention is compared with that of the reaction using antimony trioxide alone as catalyst.
Table 3: Comparison of activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide catalyst during solid state polymerization of low viscosity polymers formed in examples 1 and 3
From table 3 it is clear that by using the catalyst system (antimony trioxide and alkali metal salt of paratoluene sulfonic acid) of the invention, the residence time, for solid state polymerization to obtain polyester of intrinsic viscosity of around 0.92 dl/g, is lowered.
In table 4, the solid state polymerization (SSP) activity of the reaction using catalyst system of the invention is compared with that of the reaction using antimony trioxide alone as catalyst.
Table 4: Comparison of activity of the catalyst system comprising antimony trioxide and sodium para toluene sulphonate with antimony trioxide catalyst during solid state polymerization of low viscosity polymers formed in examples 2 and 4
As seen from the table 4, when antimony trioxide alone is used as the catalyst higher residence time (16 hours) is required to obtain polyester of intrinsic viscosity 0.764 dl/g.
Polyester of comparable intrinsic viscosity (0.767 dl/g) is obtained at a lower residence time (12 hours) by using the catalyst system of the invention.
As evident from the foregoing, the catalyst system of the invention exhibits improved activity that enables synthesis of polyester with high productivity and throughput. Thus the synthesis is more efficient and cost effective. Moreover, due to the improved catalyst activity and to the consequent increase in productivity the reaction temperatures can be kept low to avoid unwanted side reactions.
The above description is illustrative only and is not limiting. The present invention is defined by the claims that follow and their full range of equivalents.
Claims
1. A catalyst system for polyester synthesis, the catalyst system comprising atleast 10 ppm of an alkali metal salt of paratoluene sulphonic acid and atleast 50 ppm of antimony wherein the antimony is present in the form of a compound.
2. The catalyst system as claimed in claim 1 wherein the antimony is present in an amount ranging from 50 to 1500 ppm and the alkali metal salt is present in an amount ranging from 10 to 500 ppm.
3. The catalyst system as claimed in claim 1 wherein the alkali metal salt is a sodium salt or a potassium salt.
4. A process for synthesis of a polyester resin in the presence of catalyst system as claimed in any one of the claims 1 to 3, the process comprising esterifying at least one organic dicarboxylic acid or derivatives thereof with a polyol at temperature in the range of 25O0C to 29O0C to obtain a carboxylic acid ester and melt polymerizing the acid ester at temperature in the range of 2600C to 3000C to obtain a low viscosity polyester.
5. The process as claimed in claim 4 wherein the dicarboxylic acid is terephthalic acid and the polyol is ethylene glycol.
6. A polyester having an intrinsic viscosity in the range of 0.20 to 0.45 dl/g synthesized by the process as claimed in claim 4.
7. A polyester having an intrinsic viscosity in the range of 0.45 to 0.65 dl/g synthesized by the process as claimed in claim 4.
8. The process as claimed in claim 4 further comprising reacting the low viscosity polyester in the solid state at a temperature in the range of 200 to 2400C to form a polyester having intrinsic viscosity in the range of 0.70 to 1.20 dl/g
9. A polyester having intrinsic viscosity in the range of 0.70 to 1.20 dl/g prepared by the process as claimed in claim 8.
10. Films, fibers, filaments and yarns prepared from the polyester as claimed in anyone of the claims 7 or 9
11. Shaped articles prepared from the polyester as claimed in claim 9.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IN1352/MUM/2007 | 2007-07-16 | ||
| IN1352MU2007 | 2007-07-16 |
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| WO2009053998A3 WO2009053998A3 (en) | 2009-07-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| PCT/IN2008/000456 WO2009053998A2 (en) | 2007-07-16 | 2008-07-16 | Catalyst for the production of polyester |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4835247A (en) * | 1988-08-08 | 1989-05-30 | The Goodyear Tire & Rubber Company | Process for the synthesis of a copolyester adhesive resin |
| JPH08245778A (en) * | 1995-03-13 | 1996-09-24 | Nippon Ester Co Ltd | Production of copolyester |
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