WO1996022318A1 - Procede de polymerisation d'oligomeres de polyesters - Google Patents

Procede de polymerisation d'oligomeres de polyesters Download PDF

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Publication number
WO1996022318A1
WO1996022318A1 PCT/US1996/000327 US9600327W WO9622318A1 WO 1996022318 A1 WO1996022318 A1 WO 1996022318A1 US 9600327 W US9600327 W US 9600327W WO 9622318 A1 WO9622318 A1 WO 9622318A1
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Prior art keywords
stage
bis
oligomer
terephthalate
pressure
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PCT/US1996/000327
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English (en)
Inventor
John Maurice Iwasyk
Julie Anderson Rakestraw
Kenneth Wayne Leffew
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E.I. Du Pont De Nemours And Company
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Publication date
Priority claimed from US08/576,657 external-priority patent/US5811496A/en
Application filed by E.I. Du Pont De Nemours And Company filed Critical E.I. Du Pont De Nemours And Company
Priority to AU46968/96A priority Critical patent/AU4696896A/en
Publication of WO1996022318A1 publication Critical patent/WO1996022318A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/24—Stationary reactors without moving elements inside
    • B01J19/2415—Tubular reactors
    • B01J19/243—Tubular reactors spirally, concentrically or zigzag wound
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/24—Stationary reactors without moving elements inside
    • B01J19/245—Stationary reactors without moving elements inside placed in series
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
    • B01J3/04—Pressure vessels, e.g. autoclaves
    • B01J3/042—Pressure vessels, e.g. autoclaves in the form of a tube
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00054—Controlling or regulating the heat exchange system
    • B01J2219/00056—Controlling or regulating the heat exchange system involving measured parameters
    • B01J2219/00069—Flow rate measurement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
    • B01J2219/00099—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor the reactor being immersed in the heat exchange medium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00162—Controlling or regulating processes controlling the pressure

Definitions

  • TITLE PROCESS FOR POLYMERIZATION OF POLYESTER OLIGOMERS FIELD OF THE INVENTION This invention is directed to an improved process for the polymerization of polyester oligomers produced from dicarboxylic acids, such as terephthalic acid (TPA), or their esters. More particuarly, the invention involves polymerizing the oligomer in a pipeline reactor having at least two stages, to obtain an ends- balanced oligomer having a degree of polymerization of 2 to 40. Such oligomers are useful in an overall process for making higher molecular weight polyesters.
  • TPA terephthalic acid
  • Polyester production from diacids or their esters and polyols or glycols, for example, from dimethyl terephthalate (DMT) and ethylene glycol is well known. This has usually been accomplished by stage-wise melt polymerization under vacuum conditions. In order for such methods of polymerization to achieve commercially acceptable levels, the condensation by-products, for example, ethylene glycol, need to be removed from the reaction system. Typically, the by-products and excess glycol are vaporized, usually under vacuum conditions, and end up as a waste-water stream. Subsequently, the waste-water stream requires treatment and may contribute volatile organic emissions to the air. Moreover, the presence of excess ethylene glycol in the polymerization reactor may have a deleterious effect on the physical properties of the product.
  • DMT dimethyl terephthalate
  • a single stage reaction process is described in U.S. Patent No. 3,480,587.
  • the reference describes preparation of a fiber or fihn-forming polyester or copolyester where at least part of the polycondensation takes place while the liquid reaction mixture flows along a long, narrow tube in turbannular flow.
  • the movement of the liquid along the tube is cocurrent with the flow of a gaseous fluid which is chemically inert to the liquid reaction mixture.
  • the rate of flow of the gaseous fluid is such that during at least part of the residence time the partial pressure of glycol in the gaseous fluid is below the equilibrium partial pressure for the reaction mixture.
  • the ratio of the sectional area of the tube divided by the length of the wetted perimeter should preferably be less than 2.5 cm.
  • the reaction mixture entering the tube is of average degree of polymerization 27 and the product issuing from the tube is of Viscosity Ratio between 1.7 and 2.0 in 1% solution orthochloro- phenol at 25°C (e.g.. of degree of polymerization of 65 to 100 units).
  • ends balance is meant the ratio of the carboxyl to the hydroxy functional groups in the oligomer product.
  • the process of the present invention comprises a multistage pipeline reactor, having at least two stages, for polymerization of a polyester oligomer in which the carboxy /hydroxy ends balance is decreased and the degree of polymerization (DP) of an oligomer may also be raised, from an intial DP of about 2 to 10 to a product DP, at the end of the process, of about 2 to 40.
  • DP degree of polymerization
  • the process of this invention involves a process for preparing a prepolymer in a pipeline reactor having at least two stages, which process comprises: (a) in a first stage of the reaction process, in a pipeline reactor, optionally in the presence of a polyester polymerization catalyst, mixing and contacting a polyol monomer with an oligomer feed material in melt form, wherein the oligomer feed material has a degree of polymerization (DP) of 2 to about 10 and is the reaction product of a mixture of monomers comprising a dicarboxylic acid or its ester and the polyol, and wherein the polyol monomer to acid ratio of the reaction mixture is about 1.01 : 1 to about 1.5: 1, and wherein the reaction mixture is within a predetermined temperature and pressure range;
  • DP degree of polymerization
  • the present invention maximizes the utility of the pipeline reactor by beginning with feed material of a low molecular weight oligomer, thus avoiding handling of the acid/alcohol slurry, as well as avoiding excessive melt polymerization prior to the introduction of the feed to the pipeline reactor.
  • the material is discharged from the pipeline reactor prior to reaching viscosities high enough to inhibit flow of the polyester.
  • the present invention employs an inert gas such as nitrogen, under positive pressure, thereby eliminating or reducing the problems of leakage of air into the system, which can cause degradation reactions and the development of color in traditional vacuum polymerization systems. Also, the present process has the advantange of eliminating or reducing the need for wastewater handling, vaccuum jets, and emissions problems, without requiring expensive and sometimes unreliable vacuum pump systems.
  • an inert gas such as nitrogen
  • Figure 1 is a schematic drawing of one embodiment of the present process employing a multi-stage pipeline reactor, as may be practiced on a commercial scale.
  • Figure 2 is a schematic drawing of one embodiment of the present invention employing a multi-stage pipeline reactor as used to produce a polyester oligomer in smaller quantities.
  • this invention is directed to an improved process and apparatus for the polymerization of polyester produced from dicarboxylic acids or their esters, such as terephthalic acid (TPA).
  • TPA terephthalic acid
  • the process employs a pipeline reactor having at least two stages.
  • the process polymerizes an oligomeric feed material having a degree of polymerization of 2-10 and typically produces an oligomeric product having a degree of polymerization of 2-40, preferably 5-35, most preferably 8 to 30.
  • a polyol such as ethylene glycol
  • a low molecular weight polyester oligomer prepolymer melt wherein the mole ratio of polyol to acid allows for the desired ends-balancing which enables the production of high molecular weight polyester during subsequent processing.
  • the polyol to acid ratio of the reaction mixture is suitably about 1.01 : 1 to about 1.5: 1 , preferably about 1.1 : 1 to about 1.4: 1 , most preferably 1.15: 1 to 1.3 : 1.
  • the molecular weight of the prepolymer is increased by removal of volatile reaction by-products, including water and polyol from the melt.
  • the carboxyl/hydoxyl ends balance of the the oligomeric feed material is typically 1 : 1 to 1 :0.25 (one:one to one:one-fourth) and the carboxy/hydoxyl ends balance of the oligomeric product is suitably 1:2 to 1 :8.
  • a polyol or diol such as ethylene glycol
  • a polyol or diol such as ethylene glycol
  • a polyol or diol such as ethylene glycol
  • the oligomer is sometimes also referred to as a prepolymer with respect to the high molecular weight polyester.
  • a polyester oligomer of low molecular weight, in melt form, is fed to the entrance of a pipeline reactor.
  • polyester oligomer which has been previously esterified, handling problems, recognized in the prior art and commonly encountered with feeding slurries of glycol and terephthalic acid or the like, are eliminated.
  • the first stage is operated within a range between 20 psig and 300 psig. Operation above the vapor pressure may be employed to avoid the polyol flashing and then rapidly flowing downstream, which could lead to major inefficiencies. Higher pressure may also be employed to obtain efficient mixing for ends balancing, and to reduce the volume and costs of the reactor by maintaining a high liquid phase fraction ratio, and, finally, to reduce the amount of polyol loss. On the other hand, lower vapor pressures may be more economical due to lower capital and operating costs for nitrogen injection in the case wherein nitrogen is injected at the end of the first stage of the reactor, as preferred.
  • the residence time in the first stage is preferably sufficient to drive the esterification reaction to equilibrium, or to have the esterification reaction approach equilibrium. Otherwise, an excess amount of polyol may be lost due to flashing in the subsequent lower pressure second stage.
  • the process is preferably designed to operate as close to equilibrium as possible.
  • the residence time for both the first and second stage is preferably designed for the maximum throughput at minimum reactor temperature conditions so that the product composition will be relatively constant with turndown ratio and any temperature changes.
  • the skilled artisan will appreciate that practical limitations to the turndown ratio and reaction temperature must be considered to avoid designing an oversize reactor which will provide excessive residence times which would lead to degradation under standard operating conditions.
  • the process temperature should be above the melting point of the oligomer in the reaction mixture, and should be sufficiently high so that reactor holdup time is not excessive. However, the temperature should not be so high that undesirable side reactions are excessive.
  • Each stage of the pipeline reactor can be operated at different temperatures or at the same temperature in a common shell to minimize costs.
  • the first and second stages may contain mixers, preferably static mixers.
  • mixers preferably static mixers.
  • there is an initial mixer in the first stage which is the primary mixing device for contacting the polyol with the oligomer reactant.
  • the molecular weight of the prepolymer is increased, ultimately to the desired level, by the removal of volatile reaction by-products, including water and the polyol, for example glycol, from the melt.
  • an inert gas is employed to drive the reaction in the second stage.
  • the inert gas is preferably introduced at the end of the first stage to allow intimate mixing-and possible dissolution in the oligomer phase. This has the advantage that the mixture of inert gas and oligomer upon pressure letdown will foam and froth, but not excessively, such that a greater amount of interfacial area will be generated, which is beneficial for the condensation reaction which is to take place in the second stage.
  • Additives and catalysts may optionally be injected and mixed either in the first or second stage, or both.
  • a preferred embodiment of the present invention is shown, including a pipeline reactor generally shown at 1 1, which reactor is divided into two stages I and II.
  • pipeline reactor is typically meant an axially elongated substantially cylindrically-shaped apparatus, although shapes may vary if not detrimental to the purpose of this invention.
  • first stage and second stage are not meant to exclude additional stages at any point within the reaction process or along the pipeline reactor.
  • a dicarboxylic acid or its ester such as terephthalic acid (TPA)
  • TPA terephthalic acid
  • a polyol usually a diol
  • ethylene glycol such as ethylene glycol
  • the esterification produces a low molecular weight oligomer of average degree of polymerization of 2 to about 10, preferably about 5 to about 10.
  • the oligomer produced typically has an intrinsic viscosity (IV) of 0.09 to 0.16 dl/gm, and carboxyl ends of 600 to 1200 Eq/10 6 gms.
  • the carboxyl ends of the oligomer feed material produced in the esterifier 1 are subsequently reduced in the present process by means of the pipeline reactor.
  • the DP also increases by the end of this process, this may not necessarily be the case.
  • the DP of the reaction mixture will be increased in the second stage of the process, the DP will actually decrease, in some cases to a greater extent, in the first stage of the reactor.
  • additional diol is injected at injection point 2 to provide sufficient diol for formation of a prepolymer with a mole ratio and ratio of carboxyl/hydroxyl ends appropriate to allow production of high molecular weight polymer in subsequent processing steps.
  • a catalyst and/or other additives such as delusterants, may be added with the diol.
  • the diol and molten oligomer flow through a static mixer section 3 to provide for improved mixing and reactant contact.
  • the mixture flows into a section or zone 4 of the pipeline reactor, which zone operates under pressure and provides sufficient residence time to allow for reaction.
  • the pipeline reactor operates at a lower pressure than in the first stage and functions to increase the molecular weight of the polymer melt.
  • An inert gas may be injected at injection point 5, preferably just before the end of the first stage of the reactor. It is preferable to inject the inert gas at that location, rather than at the beginning of the second stage, to increase mixing of the inert gas with the reaction mixture.
  • the mixture of melt and inert gas flow cocurrently, optionally through static mixer 6, to provide improved mixing and reactant contact.
  • the mixture passes through a letdown valve 7 or other device to reduce the pressure to second stage II which operates at substantially atmospheric pressure, with the polycondensation reaction driven by the reduction in partial pressure of the gas and diol provided by injection of the inert gas.
  • vaccuum may also be applied in stage II. Preferably, however, the use of vaccuum is not necessary.
  • the reaction mixture then passes into pipeline reactor section 8 and produces prepolymer having an average degree of polymerization of 2 to 40, preferably about 5 to 35, more preferably about 10 to 25. Such prepolymer is suitable for subsequent processing to form high molecular weight polymer.
  • Prepolymer exits the pipeline reactor at 9 and may be fed to a subsequent polymerization reactor, generally indicated as 10 in Figure 1, with or without intermediate processing before, for example, solid-state polymerization, wherein the prepolymer may first be formed into semi-crystalline pellets and/or subjected to further melt polymerization.
  • a subsequent polymerization reactor generally indicated as 10 in Figure 1
  • the prepolymer may first be formed into semi-crystalline pellets and/or subjected to further melt polymerization.
  • the pipeline reaction process as described herein is not necessarily limited to two stages. It is within the scope of this invention to process the oligomer in multiple stages of a pipeline reactor.
  • an additional stage III, prior to polymerization reactor 10, is referenced on Figure 1. Any additonal stages would be provided with the desired or proper pressure conditions of inert gas addition or optional vacuum as required.
  • the oligomer which was prepared remotely, was solidified and ground into a powder prior to feeding it to a pipeline reactor.
  • a feeder 21 which may be for example a loss-in-weight feeder model LWF-T20, manufactured by K-Tron Corporation of Pitman, New Jersey.
  • the powdered oligomer is metered into a melting device 22, such as a 30-mm twin screw extruder manufactured by Werner & Pfleiderer Corporation of Ramsey, New Jersey.
  • the oligomer is melted and conveyed through the extruder.
  • the molten oligomer exits the extruder through an oil-jacketed, heated transfer line 23.
  • the heated fluid is provided by a heated oil bath 24 with a circulating pump.
  • the heated oil bath may be a high temperature oil bath distributed by Brinkmann Instruments of Westbury, New York and manufactured by Lauda AG of Germany.
  • the heated transfer lines may be heated using circulating heat transfer fluids such as high temperature silicone oil manufactured by Dow-Corning of Midland, Michigan, or Marlotherm S dibenzyltoluene heat transfer fluid manufactured by Huls America, Inc. of Piscataway, New Jersey.
  • electrical heating or other means may be used to provide sufficient heat to maintain the oligomer at its desired temperature above its freezing point.
  • the molten oligomer flows through a three-way valve 25 and is directed either to the pipeline reactor, or, on startup and shutdown, to waste collection 26.
  • the oligomer stream flows through an oil-traced heated transfer line 27. This transfer line is heated by a circulating oil pump in a second oil bath 28.
  • the heated oil bath may be a model T.C.V. manufactured by Tamson of Holland or similar device.
  • the oligomer stream flows to a metering pump 29 located in a heated oil bath 28.
  • the pump may be a model HPB 1/4 capacity melt pump manufactured by Zenith Nichols of Waltham, Massachusetts.
  • the metering pump is used to control the flow of oligomer to the pipeline reactor.
  • the oligomer flows from the melt through a heat transfer fluid jacketed transfer line 30 into the first stage (I) of the pipeline reactor which is located within a heat transfer fluid filled bath 31.
  • the heated oil bath may be a Lauda-Brinkmann high temperature oil bath as described above.
  • the pressure of the oligomer stream is measured using, for example, a pressure transducer 32 manufactured by Dynisco Instruments of Philadelphia, Pennsylvania.
  • Ethylene glycol, optionally mixed with catalyst is injected into the molten oligomer stream through injection valve 33.
  • Possible catalysts used to aid the esterification reaction include antimony glycolate, such as S-24 manufactured by Elf Atochem North America of Philadelphia, Pennsylvania, or Sb 2 O3, antimony trioxide, manufactured by Laurel Industries, Inc.
  • a metering pump 34 such as a model 500D syringe pump with Series D controller, manufactured by Isco, Inc. of Lincoln. Iowa, is used to control the flow of the ethylene glycol.
  • static mixers 35 such as a Kenics mixer with 1/4" OD and 20-25 mixer elements manufactured by Kenics Static Mixers of Chemineer, Inc., of North Andover, Massachusetts, to provide improved mixing between the oligomer and ethylene glycol.
  • Esterification of the oligomer and glycol occurs in the pipeline reactor section 36, providing ends-balancing by the incorporation of ethylene glycol into the oligomer, thus reducing the number of carboxyl ends and increasing the mole ratio of ethylene glycol/terephthalic acid, to allow the production of high molecular weight polymer in subsequent processing steps.
  • Nitrogen is injected through an injection valve 37 into the center of the melt stream at the end of the first stage of the pipeline reactor.
  • the purpose of the nitrogen stream is to reduce the partial pressure of the ethylene glycol in the second stage of the pipeline reactor (II) and allow polymerization to proceed as desired.
  • the degree of polymerization upon exit is controlled by varying the nitrogen flow rate using a metering valve 38 and reading the throughput from a rotameter 39, such as a model R-6-15-A obtained from Brooks Instrument Division of Emerson Electric Co. of Hatfield, Pennsylvania.
  • the oligomer and nitrogen may flow through static mixer section 40, comprised, for example, of two SMX mixers with 3/8" OD manufactured by Koch Engineering Company, Inc. of Wichita, Kansas and a 10-15 mixer element with 3/8" OD manufactured by Kenics Static Mixers of Chemineer, Inc., of North Andover, Massachusetts.
  • static mixer section 40 comprised, for example, of two SMX mixers with 3/8" OD manufactured by Koch Engineering Company, Inc. of Wichita, Kansas and a 10-15 mixer element with 3/8" OD manufactured by Kenics Static Mixers of Chemineer, Inc., of North Andover, Massachusetts.
  • static mixer section 40 comprised, for example, of two SMX mixers with 3/8" OD manufactured by Koch Engineering Company, Inc. of Wichita, Kansas and a 10-15 mixer element with 3/8" OD manufactured by Kenics Static Mixers of Chemineer, Inc., of North Andover, Massachusetts.
  • the reaction, as described has been run successfully both with and without static mixer
  • the two-phase mixture, nitrogen, water and ethylene glycol vapors and prepolymer melt flows from the pipeline reactor oil bath 31 through a jacketed transfer line to the separator 43.
  • the melt is collected in a quench bath in a sample collection bealjer 44.
  • the vapor is removed through an exhaust line to a bank of condensers 45 to remove the ethylene glycol and water from the gas stream.
  • the nitrogen stream then flows through vacuum pumps to remove any residual ethylene glycol prior to discharge through a vent line (not shown).
  • Data on system temperatures and pressures are recorded using a Kaye 4S Plus Digistrip recorder. Process monitoring of selected points is also accomplished using Genesis software version 3.52 on a Texas Microsystems N286 personal computer.
  • the process of the present invention is generally applicable for use regarding any dihydroxy ester of any dicarboxylic acid, or low molecular weight oligomer thereof.
  • Diol addition, for ends balancing, would be dependent on the oligomer being processed.
  • catalyst or other additives are introduced to the system via glycol solution in stage I.
  • Suitable catalysts for facilitating the polymerization include any one or more polyester polymerization catalysts known in the prior art to catalyze such polymerization processes, such as, but not limited to, compounds of antimony, germanium and titanium.
  • Antimony trioxide (SD2O3) is an especially effective catalyst which may be introduced, for convenience, as a glycolate solution in ethylene glycol. Examples of such catalysts are found in U.S. 2,578,660, U.S. 2,647,885 and U.S. 2,789,772, which are incorporated herein by reference.
  • the diacid components in the polyesters to which this invention pertains are suitably alkyl dicarboxylic acids which contain from 4 to 36 carbon atoms, diesters of alkyl dicarboxylic acids which contain from 6 to 38 carbon atoms, aryl dicarboxylic acids which contain from 8 to 20 carbon atoms, diesters of aryl dicarboxylic acids which contain from 10 to 22 carbon atoms, alkyl substituted aryl dicarboxylic acids which contain from 9 to 22 carbon atoms, or diesters of alkyl substituted aryl dicarboxylic acids which contain from 11 to22 carbon atoms.
  • the preferred alkyl dicarboxylic acids contain from 4 to 12 carbon atoms.
  • alkyl dicarboxylic acids include glutaric acid, adipic acid, pimelic acid and the like.
  • the preferred diesters of alkyl dicarboxylic acids contain from 6 to 12 carbon atoms.
  • a representative example of such a diester of an alkyl dicarboxylic acid is azelaic acid.
  • the preferred aryl dicarboxylic acids contain from 8 to 16 carbon atoms.
  • Some representative examples of aryl dicarboxylic acids are terephthalic acid, isophthalic acid and orthophthalic acid.
  • the preferred diesters of aryl dicarboxylic acids contain from 10 to 18 carbon atoms.
  • diesters are aryl dicarboxylic acids, including diethyl terephthalate, diethyl isophthalate, diethyl orthophthalate, dimethyl naphthalate, diethyl naphthalate and the like.
  • the preferred alkyl substituted aryl dicarboxylic acids contain from 9 to 16 carbon atoms and the preferred diesters of alkyl substituted aryl dicarboxylic acids contain from 1 1 to 15 carbon atoms.
  • Dihydroxy esters of dicarboxylic acids used in the processes described herein are monomeric compounds that can polymerize to a polymer.
  • Examples of such compounds are bis(2-hydroxyethyl) terephthalate, bis(4-hydroxybutyl)- terephthalate, bis(2-hydroxyethyl) naphthalenedioate, bis(2-hydroxyethyl) isophthalate, bis[2-(2-hydroxyethoxy)ethyl]terephthalate, bis[2-(2-hydroxy- ethoxy)ethyl] isophthalate, bis[(4-hydroxymethylcyclohexyl)methyl] terephthalate, bis[(4-hydroxymethylcyclohexyl)methyl] isophthalate, and a combination of bis(4-hydroxybutyl) terephthalate and their oligomers. Mixtures of these monomers and oligomers may also be used.
  • the diol component for polyesters used in the invention herein is normally comprised of glycols containing from 2 to 12 carbons atoms, glycol ethers containing from 4 to 12 carbon atoms and polyether glycols having the structural formula HO-(AO) n H, wherein A is an alkylene group containing from 2 to 6 carbon atoms and wherein n is an integer from 2 to 400.
  • polyether glycols will have a molecular weight of about 400 to 4000.
  • glycols normally contain from 2 to 8 carbon atoms with preferred glycol ethers containing from 4 to 8 carbon atoms.
  • Some representative examples of glycols that can be utilized as the diol component include ethylene glycol, 1,3-propylene glycol, 1 ,2-propylene glycol, 2,2-diethyl-l,3-propanediol, 2,2-dimethy 1-1, 3 -propane diol, 2-ethyl-2-butyl-l,3-propane diol, 2-ethyl-2- isobutyl-l,3-propane diol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane diol, 1 ,6-hexane diol, 2,2,4-trimethyl- 1 ,6-hexane diol, 1 ,3-cyclohexane dimethanol, 1,4-cyclohexane dimethanol, 2,2,4 ,4
  • Prepolymers of polyester copolymers can also be formed by the process of this invention.
  • polyesters may be modified with up to 10% by weight of a comonomer, preferably less than 5% by weight.
  • Comonomers can include diethylene glycol (DEG), triethylene glycol, 1,4-cyclohexane dimethanol, isophthalic acid (IP A), 2,6-naphthalene dicarboxylic acid, adipic acid and mixtures thereof.
  • Preferred comonomers for poly(ethylene terephthalate) include 0-5% by weight IPA and 0.8-3% by weight DEG.
  • a “polymerizable oligomer” is meant any oligomeric material which can polymerize to a polyester.
  • This oligomer may contain low molecular weight polyester, and varying amounts of monomer.
  • the reaction of dimethyl terephthalate, or terephthalic acid with ethylene glycol, when carried out to remove methyl ester or carboxylic groups usually yields a mixture of bis(2-hydroxyethyl) terephthalate, low molecular weight polymers (oligomers) of bis(2-hydroxyethyl) terephthalate and oligomers of mono(2-hydroxyethyl) terephthalate (which contains carboxyl groups).
  • Polyesters produced by the process include, but are not limited to, poly(ethylene terephthalate), poly(l,3 propylene terephthalate), poly(l,4-butylene terephthalate), poly(ethylene naphthalenedioate), poly(ethylene isophthalate), poly(3-oxa-l,5-pentadiyl terephthalate), poly(3-oxa-1.5-pentadiyl isophthalate), poly[l ,4-bis(oxymethyl)cyclohexyl terephthalate] and poly[1.4-bis(oxymethyl)- cyclohexyl isophthalate].
  • Poly(ethyiene terephthalate) is an especially important commercial product.
  • the oligomer produced in the present process can be used to make pellets for later use as feedstock to a polymerization process for making high molecular weight polyesters.
  • the present oligomers are especially useful as part of an overall process for solid-state polymerization. See for example, cocurrently pending commonly assigned applications S.N. (Docket No. CR-9638),
  • the ethylene glycol/terephthalic acid mole ratio ranged in our examples from 1.13: 1 to 1.3:1.
  • the range suitable for the invention is about 1.08:1 to about 1.3:1.
  • Catalyst added (as ppm Sb metal) 35 to 275 ppm. Oligomer as received contained 35 ppm Sb. A suitable range for this invention is about 0 to about 300 ppm Sb.
  • An example of an alternate catalyst is titanium (IV) isopropoxide (added as
  • ⁇ ppm titanium 10 ppm titanium in ethylene glycol.
  • a suitable range for this invention is about 0 to about 10 ppm.
  • the pressure in the first stage of the reactor was 57 to 273 psig, and in example 10, the pressure was 41 psig.
  • a suitable range for this invention is about 20 to 500 psig.
  • Oligomer throughput was 0.75 to 3.0 lb/hr.
  • Nitrogen flow rates in our examples ranged from 0.25 to 1.7 lbs N 2 per lb oligomer fed. Flow rates of less than 2 lbs inert gas per lb oligomer are suitable for this invention.
  • Pressure in the second stage of the reactor in our examples was atmospheric presure.
  • a suitable range of pressure in the second stage of the reaction is from about atmospheric pressure to about 25 psig.
  • the pressure in the second stage of the reaction is reduced to a value which maintains the partial pressure of the by-products at less than the equilibrium pressure of the by- products with the prepolymer melt exiting the second stage of the reactor.
  • For polyethylene terephthalate a range of about 2 mm Hg to about 100 mm Hg is suitable.
  • a suitable residence time of the reaction mixture in the first stage is from about 1 to 60 minutes, preferably 1 to 5 minutes.
  • a suitable residence time of the reaction mixture in the second stage is from about 1 to 60 minutes, preferably about 5 to 60 minutes. Such residence times will, however, depend on the desired product properties and economic efficiencies.
  • poly(ethylene terephthalate), PET, prepolymer samples with intrinsic viscosity (IV) from 0.137 dl/gm to 0.304 dl/gm (corresponding to DPs of 8.4 to 27.1), as measured in 50/50 trifluoroacetic acid/methylene chloride, were prepared under various operating conditions in the pipeline reactor.
  • the prepolymer may be further processed, by melt-phase polymerization or solid-state polymerization, to form polyesters with commercially useful IVs for fibers, including garments, tire cord, films, bottles, molding resins, etc.
  • the feed to the pipeline reactor was terephthalic acid-based poly(ethylene terephthalate) oligomer with an intrinsic viscosity (IV) of 0.12 dl/gm and carboxyl ends of 659 Eq/10 6 gms.
  • the oligomer was prepared by melt-phase esterification of terephthalic acid and ethylene glycol. The oligomer was solidified and ground prior to feeding to the pipeline process. The oligomer feed was melted in a Werner & Pfleiderer twin-screw extruder and metered into the pipeline reactor as described above using a Zenith gear pump.
  • the oligomer feed contained 35 ppm antimony trioxide, measured as antimony metal.
  • Ethylene glycol containing a prescribed amount of catalyst solution (Antimony glycolate, S-24 from Elf
  • Atochem was injected into the pipeline using a syringe pump manufactured by either Ruska Instrument Corporation of Houston, Texas or Isco, Inc. of Lincoln, California.
  • the oligomer melt and ethylene glycol were passed through a Kenics static mixer section.
  • the ethylene glycol and oligomer were allowed to react in the first stage of the pipeline reactor to incorporate the glycol into the oligomer.
  • the first stage reactor section consisted of 10 feet of 3/8" OD coiled stainless steel tubing. Nitrogen was injected into the pipeline at a prescribed rate to reduce the partial pressure of water and glycol above the melt and drive the polymerization to the desired molecular weight through the pipeline flasher section.
  • the nitrogen and melt were passed to the second stage through Koch and Kenics static mixers.
  • the degree of polymerization of the finished product was controlled by varying the nitrogen flow rate.
  • the flasher consisted of 25 feet of 1/2" OD coiled stainless steel tubing.
  • the mixture of nitrogen and melt were passed through a letdown valve prior to the flasher section. The product was collected and quenched in a beaker at the exit from the pipeline.
  • EXAMPLE 1 Oligomer was metered at 1.0 lb/hr into the pipeline reactor. The oil bath temperature was held at 280°C. Ethylene glycol containing 1% antimony glycolate was injected at a rate of 0.0625 lb/hr, providing a mole ratio of 1.21 moles ethylene glycol/mole terephthalic acid in feed. No nitrogen was added. The pressure in the reactor section was 222 psig. The sample was collected immediately after the polyester exited the reactor section. The degree of polymerization, determined by gel permeation chromatography (GPC) was 5.04 units. The carboxyl ends, determined by titration, were 419 Eq/10 6 gms. This is a comparison example to show the effect of a one stage polymerization process without the use of a subsequent pressure reduction section. This shows the reduction in carboxyl ends and the degree of polymerization resulting from addition of the supplemental glucol.
  • GPC gel permeation chromatography
  • Oligomer was metered at 1.0 lb/hr into the pipeline reactor.
  • the oil bath temperature was held at 280°C.
  • Ethylene glycol containing 1% antimony glycolate was injected at a rate of 0.0625 lb/hr, providing a mole ratio of 1.21 moles ethylene glycol/mole terephthalic acid in feed.
  • Nitrogen was added at a rate of 1.993 lb/hr.
  • the pressure in the reactor section was 130 psig.
  • the product obtained had an average IV of 0.256 dl/gm and an average of 61 Eq/lO ⁇ gms carboxyl ends.
  • EXAMPLE 4 Oligomer was metered at 3.0 lb/hr into the pipeline reactor. The oil bath temperature was held at 280°C. Ethylene glycol containing 1% antimony glycolate was injected at a rate of 0.1875 lb/hr, providing a mole ratio of 1.21 moles ethylene glycol/mole terephthalic acid in feed. Nitrogen was added at a rate of 2.797 lb/hr. The pressure in the reactor section was 220 psig. The product obtained had an average IV of 0.193 dl/gm and an average of 318 Eq/10 ⁇ gms carboxyl ends.
  • EXAMPLE 5 Oligomer was metered at 3.0 lb/hr into the pipeline reactor. The oil bath temperature was held at 280°C. Ethylene glycol containing 1% antimony glycolate was injected at a rate of 0.1875 lb/hr, providing a mole ratio of 1.21 moles ethylene glycol/mole terephthalic acid in feed. Nitrogen was added at a rate of 1.138 lb/hr. The pressure in the reactor section was 180 psig. The product obtained had an average IV of 0.186 dl/gm and an average of 284 Eq/10 6 gms carboxyl ends.
  • EXAMPLE 6 Oligomer was metered at 1.0 lb/hr into the pipeline reactor. The oil bath temperature was held at 280°C. Ethylene glycol containing 0.75% antimony glycolate was injected at a rate of 0.0938 lb/hr, providing a mole ratio of 1.31 moles ethylene glycol/mole terephthalic acid in feed. Nitrogen was added at a rate of 2.227 lb/hr. The pressure in the reactor section was 100 psig. The product obtained had an average IV of 0.208 dl/gm and an average of 72 Eq/10 6 gms carboxyl ends.
  • EXAMPLE 7 Oligomer was metered at 1.0 lb/hr into the pipeline reactor. The oil bath temperature was held at 280°C. Ethylene glycol containing no additional catalyst was injected at a rate of 0.0781 lb/hr, providing a mole ratio of 1.26 moles ethylene glycol/mole terephthalic acid in feed. Nitrogen was added at a rate of 1.760 lb/hr. The pressure in the reactor section was 220 psig. The product obtained had an average IV of 0.189 dl/gm and an average of 84 Eq/10 6 gms carboxyl ends.
  • Oligomer was metered at 3.0 lb/hr into the pipeline reactor.
  • the oil bath temperature was held at 280°C.
  • Ethylene glycol containing 1% antimony glycolate was injected at a rate of 0.0163 lb/hr, providing a mole ratio of 1.13 moles ethylene glycol/mole terephthalic acid in feed.
  • Nitrogen was added at a rate of 2.123 lb/hr.
  • the pressure in the reactor section was 235 psig.
  • the product obtained had an average IV of 0.172 dl/gm and an average of 176 Eq/10 6 gms carboxyl ends.
  • Oligomer was metered at 0.9 lb/hr into the pipeline reactor.
  • the oil bath temperature was held at 280° C.
  • Ethylene glycol was injected at a rate of 0.0221 lb/hr, providing a mole ratio of 1.08 moles ethylene glycol/mole terepthalic acid in feed.
  • Nitrogen was added at a rate of 0.991 lb/hr.
  • the pressure in the reactor section was 41 psig.
  • the product obtained had an average IV of 0.22 dl/g and an average of 11 1 Eq/10 6 g carboxyl ends.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Polyesters Or Polycarbonates (AREA)

Abstract

La présente invention concerne un procédé amélioré de production d'un oligomère de polyester. Ce procédé recourt à un réacteur tubulaire à au moins deux étages, dans lequel le taux de polymérisation d'une matière d'alimentation oligomère est augmenté d'environ 2 à 10 jusqu'à environ 2 à 40 et le rapport entre les groupements terminaux carboxyliques et hydroxyles dans le produit est réduit. Dans une première étape du processus, un diol ou un polyol monomères, comme l'éthylène glycol, est ajouté à une masse fondue de la matière oligomère qui alimente le réacteur. Dans une deuxième étape, le poids moléculaire de l'oligomère est augmenté par élimination de sous-produits volatils de la réaction, y compris l'eau et le polyol. L'oligomère produit selon la présente invention peut être utilisé dans la fabrication de polyesters de poids moléculaire plus élevé.
PCT/US1996/000327 1995-01-20 1996-01-11 Procede de polymerisation d'oligomeres de polyesters WO1996022318A1 (fr)

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US37659695A 1995-01-20 1995-01-20
US08/376,596 1995-01-20
US08/576,657 US5811496A (en) 1995-12-21 1995-12-21 Process for polymerization of polyester oligomers
US08/576,657 1995-12-21

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0999228A2 (fr) * 1998-11-04 2000-05-10 ARTEVA TECHNOLOGIES S.à.r.l. Production de polyesters par polycondensation sous pression
US6111064A (en) * 1998-11-04 2000-08-29 The Regents Of The University Of California Pressure polymerization of polyester
EP1095960A1 (fr) * 1998-06-16 2001-05-02 Asahi Kasei Kabushiki Kaisha Systeme et procede de production de polymeres de polycondensation
DE102009009957A1 (de) * 2009-02-23 2010-08-26 Bühler AG Verfahren zur Herstellung von Polyesterpartikeln bei hohem Durchsatz in einer Linie
EP2311897A1 (fr) 2000-12-07 2011-04-20 Eastman Chemical Company Procédé de polyester à base coût utilisant un réacteur tubulaire
WO2016025228A1 (fr) * 2014-08-15 2016-02-18 Sabic Global Technologies B.V. Procédé continu de production de polybutylène téréphtalate

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2452503A1 (fr) * 1979-03-30 1980-10-24 Toray Industries Preparation de polyester
EP0240279A2 (fr) * 1986-03-31 1987-10-07 Celanese Corporation Procédé de préparation d'esters oligomères glycoliques d'acides dicarboxyliques

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2452503A1 (fr) * 1979-03-30 1980-10-24 Toray Industries Preparation de polyester
EP0240279A2 (fr) * 1986-03-31 1987-10-07 Celanese Corporation Procédé de préparation d'esters oligomères glycoliques d'acides dicarboxyliques

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1095960A1 (fr) * 1998-06-16 2001-05-02 Asahi Kasei Kabushiki Kaisha Systeme et procede de production de polymeres de polycondensation
EP1095960A4 (fr) * 1998-06-16 2003-01-22 Asahi Chemical Ind Systeme et procede de production de polymeres de polycondensation
EP0999228A2 (fr) * 1998-11-04 2000-05-10 ARTEVA TECHNOLOGIES S.à.r.l. Production de polyesters par polycondensation sous pression
US6111064A (en) * 1998-11-04 2000-08-29 The Regents Of The University Of California Pressure polymerization of polyester
US6127493A (en) * 1998-11-04 2000-10-03 Arteva North America S.A.R.L. Pressure polymerization of polyester
EP0999228A3 (fr) * 1998-11-04 2001-08-22 ARTEVA TECHNOLOGIES S.à.r.l. Production de polyesters par polycondensation sous pression
EP2311897A1 (fr) 2000-12-07 2011-04-20 Eastman Chemical Company Procédé de polyester à base coût utilisant un réacteur tubulaire
DE102009009957A1 (de) * 2009-02-23 2010-08-26 Bühler AG Verfahren zur Herstellung von Polyesterpartikeln bei hohem Durchsatz in einer Linie
WO2016025228A1 (fr) * 2014-08-15 2016-02-18 Sabic Global Technologies B.V. Procédé continu de production de polybutylène téréphtalate
CN107148439A (zh) * 2014-08-15 2017-09-08 Sabic环球技术有限责任公司 制备聚对苯二甲酸丁二醇酯的连续方法
US10377854B2 (en) 2014-08-15 2019-08-13 Sabic Global Technologies B.V. Continuous process for making polybutylene terephthalate

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