CN1136249C - Process for preparing polyethylene terephthalate - Google Patents
Process for preparing polyethylene terephthalate Download PDFInfo
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- CN1136249C CN1136249C CNB971182914A CN97118291A CN1136249C CN 1136249 C CN1136249 C CN 1136249C CN B971182914 A CNB971182914 A CN B971182914A CN 97118291 A CN97118291 A CN 97118291A CN 1136249 C CN1136249 C CN 1136249C
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- 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
- C08G63/80—Solid-state polycondensation
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- 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
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- 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
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- 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
- C08G63/785—Preparation processes characterised by the apparatus used
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Abstract
Disclosed is a process for preparing polyethylene terephthalate comprising a liquid phase polycondensation reaction step, a precrystallization step and a solid phase polycondensation reaction step, wherein the precrystallization step comprises (A) heating PET chips at a temperature (T1) not lower than Tg and not higher than 180 DEG C, with stirring the PET chips, to crystallize the PET to a crystallinity of at least 30%; (B) heating the PET chips, with allowing them to stand, to a temperature (T2) in the range of from (Tbm-40 DEG C) up to Tbm to crystallize the polyethylene terephthalate to a crystalinity of at least 30% , and (C) heating the PET chips with stirring to raise the temperature of the PET chips up to the solid phase polycondensation temperature. Precrystallization of polyethylene terephthalate can efficiently be achieved even in the case of copolymerized polyethylene terephthalate.
Description
The present invention relates to prepare the method for ethylene glycol terephthalate, relate more specifically to reach effectively the method that makes the pre-crystalline of polyethylene terephthalate prepare polyethylene terephthalate.
Polyethylene terephthalate normally prepares by step of esterification, liquid phase polycondensation reaction step and solid state polycondensation step.Yet the polyethylene terephthalate section that obtains in the liquid phase polycondensation reaction step is an amorphous, so if carry out solid state polycondensation, may lump.For this reason, before the solid state polycondensation step, usually carry out pre-crystallisation step, make the polyethylene terephthalate that obtains by the liquid phase polycondensation reaction step add thermal crystalline, then the crystalline polyethylene terephthalate is imported in the solid state polycondensation step.Yet if polyethylene terephthalate is sharply heating up or at high temperature heating to carry out pre-crystallization fast, caking or fusion take place in the polyethylene terephthalate section in system.Therefore, adopt mild intensification condition usually.
For example, the open No.45229/1983 of Japanese Patent has disclosed with 150 ℃ hot air treatment polyethylene terephthalate 1 hour, with 195 ℃ nitrogen gas stream processing 2.5 hours, makes the polyethylene terephthalate crystallization then.Yet these conditions are unfavorable, because crystallization needs for a long time, thereby cause production cost to increase.
Also have, for the polyethylene terephthalate of the copolymerization that contains minor amounts of comonomers, still do not know under which kind of heating condition the crystallization and caking or fusion do not take place effectively of this multipolymer so far, because the degree of crystallinity of multipolymer is low, and fusing point is also low.
The present invention finishes in these cases, the purpose of this invention is to provide the method for preparing polyethylene terephthalate, comprise pre-crystallisation step in this method, polyethylene terephthalate in this step (polyethylene terephthalate that comprises copolymerization) can pre-effectively crystallization.
The method for preparing polyethylene terephthalate provided by the invention comprises the pre-crystallisation step of heating polyethylene terephthalate section, this section obtains by step of esterification and liquid phase polycondensation reaction step, so that polyethylene terephthalate crystallization, and the solid state polycondensation step that heats pre-crystalline polyethylene terephthalate section, temperature is reached be higher than pre-crystalline temperature, wherein said pre-crystallisation step comprises:
(A) be not less than Tg and be not higher than 180 ℃ temperature (T
1) heating polyethylene terephthalate section down, stir these sections simultaneously, make the polyethylene terephthalate crystallization, degree of crystallinity reaches at least 3%;
(B) at (T
Bm-40 ℃) to T
BmTemperature (T
2) under, the section of heating polyethylene terephthalate makes it leave standstill simultaneously, makes the polyethylene terephthalate crystallization, and degree of crystallinity reaches at least 30%, wherein T
BmThe heat absorption that is defined as the peak-to-peak secondary peak of observed heat absorption when with differential scanning calorimeter (DSC) polyethylene terephthalate being heated with the heating rate of 10 ℃/min begins temperature;
(C) section of heating polyethylene terephthalate with the temperature of these sections that raise, reaches the temperature of solid state polycondensation.
In the present invention, step (B) is preferably in 190 ± 30 ℃ the following heating of final resin temperature 1 to 3 hour and carries out.
In the present invention, solid state polycondensation is preferably under 200 ℃ to 230 ℃ the temperature and carries out.
Fig. 1 is the example that the DSC curve of the polyethylene terephthalate that records with DSC is described.
Fig. 2 is used in an embodiment cross-sectional side view.
1: feed hopper
2: horizontal continuous heater
3: vertical continuous heater
4: horizontal continuous heater
5: air purifier
6: airheater
7: the solid state polycondensation device
8: water cooler
9: the nitrogen purge device
10: gas blower
11: well heater
Now details are as follows according to the method for preparing PETG of the present invention.
The method for preparing PETG of the present invention comprises heating poly terephthalic acid second two The pre-crystallized step of alcohol ester section, this section is to obtain by step of esterification and liquid phase polycondensation reaction step , so that the PETG crystallization, and heat pre-crystallized polyethylene terephthalate The solid state polycondensation step of ester section reaches temperature and is higher than pre-crystallized temperature, and is wherein said pre-crystallized Step is to carry out under condition as described below.
Step of esterification
Step of esterification typically uses that the slurry that contains terephthalic acid (TPA) and ethylene glycol carries out. This slurry In the content of ethylene glycol be generally the 1.02-2.0 mole, be preferably the 1.03-1.5 mole, with 1 mole to benzene two The formic acid meter. This slurry adds in the step of esterification continuously.
Among the present invention, prepare polyethylene terephthalate with terephthalic acid (TPA) and ethylene glycol as initial feed Ester. But also can use other dicarboxylic acids and/or other dihydroxylic alcohols, its consumption must not surpass 20% (mole).
The example of other dicarboxylic acids that can be used for copolycondensation except terephthalic acid (TPA) comprises aromatics Dicarboxylic acids is such as phthalic acid, M-phthalic acid, naphthalene dicarboxylic acids, diphenyl dicarboxylic acid and biphenoxyl ethane Dicarboxylic acids; Aliphatic dicarboxylic acid is such as adipic acid, decanedioic acid, azelaic acid and decane dicarboxylic acid; The alicyclic ring dicarboxylic acids, Such as cyclohexane dicarboxylic acid.
The example of other dihydroxylic alcohols that can be used for copolycondensation except ethylene glycol comprises aliphatic binary Alcohol is such as 1,3-PD, 1,2-PD, BDO, neopentyl glycol, 1,6-hexylene glycol and 1,12-Dodecanediol; The alicyclic ring dihydroxylic alcohols is such as cyclohexanedimethanol; And aromatic dihydroxy compound, such as bis-phenol Class, quinhydrones and 2,2-two (4-beta-hydroxy ethoxyl phenenyl) propane.
Among the present invention, except terephthalic acid, be preferably and use m-phthalic acid as the dicarboxylic acid component, its consumption is all dicarboxylic acid components' 1-5% (mole).
Esterification is to comprise that by use the device of at least two mutual placed in-line esterifiers carries out under ethylene glycol refluxes, and water or alcohol that reaction simultaneously forms are exhausted from system by fractional column.
Esterification can be carried out under the following conditions: in the fs esterification, temperature is generally 240-270 ℃, is preferably 245-265 ℃, and pressure is generally 0.2-3kg/cm
2-G is preferably 0.5-2kg/cm
2-G; In the end in the stage esterification, temperature is generally 250-280 ℃, is preferably 255-275 ℃, and pressure is generally 0-1.5kg/cm
2-G is preferably 0-1.3kg/cm
2-G.
When esterification divided two stages to carry out, the first and second stage esterification conditions were respectively in the scope of above-mentioned first and final stage.When esterification divides the three or more stages to carry out, except that the fs from second the polycondensation condition to final stage be from above-mentioned first and the condition of final stage between select.
For example, when esterification was carried out in three stages, the subordinate phase esterification is carried out under the following conditions: temperature was generally 245-275 ℃, is preferably 250-270 ℃, and pressure is generally 0-2kg/cm
2-G is preferably 0.2-1.5kg/cm
2-G.
Transformation efficiency for each stage esterification has no particular limits, but preferably transformation efficiency increased progressively step by step with each stage.The transformation efficiency of final stage esterification generally reaches and is not less than 90%, is preferably and is not less than 93%.
Though esterification can not add other component except that terephthalic acid and ethylene glycol and carry out, and also can add a small amount of basic cpd, for example, tertiary amine, as Trimethylamine 99, tri-n-butyl amine and benzyl dimethyl amine; Quaternary ammonium compound is as tetraethylammonium hydroxide, hydroxide tetra-n-butyl ammonium and benzyltrimethyl ammonium hydroxide; And Quilonum Retard, yellow soda ash, salt of wormwood and sodium acetate.Adding basic cpd in esterification is preferably, because the unitary ratio of terephthalic acid dioxy vinyl acetate (dioxyethylene terephthalate) component in the polyethylene terephthalate main chain can remain on relatively low level.
The number-average molecular weight of the esterification products that obtains by above-mentioned step of esterification (low polycondensate) is generally 500 to 5,000.Then the esterification products that obtains is supplied with the liquid phase polycondensation reaction step.
The liquid phase polycondensation reaction step
Liquid phase polycondensation reaction is following in the liquid phase polycondensation reaction step carries out: decompression and heat this system with the temperature of the polyethylene terephthalate fusing point that is not less than gained in the presence of polycondensation catalyst, the dibasic alcohol that will react generation simultaneously boils off from system.
Liquid phase polycondensation reaction can be undertaken by a stage or a plurality of stage.When liquid phase polycondensation reaction carried out with the multistage, the temperature of fs polycondensation was generally 250-290 ℃, was preferably 260-280 ℃, and pressure is the 500-20 torr, is preferably the 200-30 torr; The temperature of final stage polycondensation is 265-300 ℃, is preferably 270-295 ℃, and pressure is the 10-0.1 torr, is preferably the 5-0.1 torr, more preferably the 2-0.1 torr.
When liquid phase polycondensation reaction carried out in two stages, first and second stages polycondensation condition was respectively in the condition and range of above-mentioned first and final stage.When liquid phase polycondensation reaction when the multistage carries out in three stages or more, except that the fs from second the polycondensation condition to final stage be from above-mentioned first and the condition of final stage between select.
For example, when liquid phase polycondensation reaction carried out in three stages, the subordinate phase polycondensation was carried out under the following conditions: temperature is generally 260-295 ℃, is preferably 270-285 ℃, and pressure is generally the 50-2 torr, is preferably the 40-5 torr.
Limiting viscosity (IV) for the polyethylene terephthalate that makes with liquid phase polycondensation reaction has no particular limits, and is to increase progressively step by step along with each stage but be preferably limiting viscosity.The limiting viscosity of the polyethylene terephthalate that the final stage polycondensation obtains (IV) is generally 0.35-0.80dl/g, is preferably 0.45-0.75dl/g, is preferably 0.55-0.75dl/g.
The viscosity calculations of solution obtained when limiting viscosity (IV) can be from 25 ℃, and this solution is 1.2 gram polyethylene terephthalates to be dissolved in 15 milliliters the orthomonochlorphenol by the limit heating edge, and cooling obtains then.
In the end the degree of crystallinity of the polyethylene terephthalate that obtains in the stage liquid phase polycondensation reaction generally is not less than 2%.
Liquid phase polycondensation reaction preferably carries out in the presence of polycondensation catalyst and stablizer.The example of operable polycondensation catalyst comprises germanium compound, as germanium dioxide, tetraethoxy germanium and four n-butoxy germanium; Antimony compounds is as ANTIMONY TRIOXIDE SB 203 99.8 PCT, antimony acetate, tetraethoxy antimony and four n-butoxy antimony; And titanium compound, as four titanium butoxide and four titanium propanolates.In polycondensation catalyst, germanium dioxide is preferred, and this is because the polyethylene terephthalate that obtains has excellent color harmony transparency.ANTIMONY TRIOXIDE SB 203 99.8 PCT and antimony acetate also are preferred, and this is because the polyethylene terephthalate that obtains has excellent crystallization rate and tone.
The example of stablizer has phosphorus compound, comprises phosphoric acid ester, as trimethyl phosphite 99, triethyl phosphate, TRI N BUTYL PHOSPHATE, trioctyl phosphate, triphenylphosphate and tricresyl phosphate hydroxytoluene ester; Phosphorous acid ester is as triphenyl phosphite, tricresyl phosphite dodecane ester and trisnonyl phenyl phosphite; Phosphate ester acid is as acid methyl orthophosphoric acid, acidic isopropyl phosphate, acid butyl phosphate, dibutyl phosphate, monobutyl phosphate and dioctylphosphoric acid ester; Phosphoric acid; And Tripyrophosphoric acid.By in esterifier, adding phosphorus compound, can improve the color harmony thermostability of the polyethylene terephthalate of gained.
In the present invention, except that polycondensation catalyst, can also add cobalt compound, manganic compound or magnesium compound.
The example of cobalt compound comprises cobalt chloride, rose vitriol, cobaltous hydroxide, Xiao Suangu, cobalt oxalate, cobaltous formate, cobaltous acetate, acetylacetone cobalt and cobaltous benzoate.By in esterifier, adding cobalt compound, can quicken esterification.
The example of manganic compound comprises manganous acetate, manganese acetylacetonate, manganous sulfate, manganous carbonate and manganous nitrate.By in esterifier, adding manganic compound, can quicken esterification.
The example of magnesium compound comprises sal epsom, magnesium nitrate, magnesium acetate, magnesium chloride, magnesiumcarbonate, magnesium citrate, magnesium lactate and magnesium oxalate.By in esterifier, adding magnesium compound, can quicken esterification.
Above-claimed cpd generally adds with the form of its aqueous solution.Its water consumption is preferably the least possible.
The consumption of phosphorus compound in 1 mole of terephthalic acid, is generally 5-200ppm, is preferably 10-100ppm (in phosphorus atom).
The consumption of cobalt compound in 1 mole of terephthalic acid, is generally 5-200ppm, is preferably 10-60ppm (in cobalt metal).
The consumption of manganic compound in 1 mole of terephthalic acid, is generally 10-200ppm, is preferably 20-100ppm (in manganese metal).
The consumption of magnesium compound in 1 mole of terephthalic acid, is generally 5-200ppm, is preferably 15-50ppm (in MAGNESIUM METAL).
The consumption of polycondensation catalyst in the weight of terephthalic acid and ethylene glycol mixture, it is desirable to 0.0005 to 0.2% (weight), is preferably 0.001 to 0.05% (weight) (in metal in the polycondensation catalyst).
The consumption of stablizer in the weight of terephthalic acid and ethylene glycol mixture, it is desirable to 0.001 to 0.1% (weight), is preferably 0.002 to 0.02% (weight) (in phosphorus atom in the stablizer).
Polycondensation catalyst and stablizer can add in above-mentioned step of esterification, perhaps add in the fs reactor in the liquid phase polycondensation reaction step.
As mentioned above, can contain in the polyethylene terephthalate that obtains by the liquid phase polycondensation reaction step from the component unit of other dicarboxylic acid except that terephthalic acid with from the component unit of other dibasic alcohol except that ethylene glycol, its content is no more than 20% (mole).Good especially is from the 1-5% (mole) of the unitary content of the component of m-phthalic acid for all dicarboxylic acid units.
In the present invention, the unitary content of ethylene glycol terephthalate component that it is desirable to by following formula (I) expression is 95.0-99.0%, and the unitary content of being represented by following formula (II) of terephthalic acid dioxy vinyl acetate component is 1.0-5.0%:
The polyethylene terephthalate that obtains in the final stage liquid phase polycondensation reaction device generally is molded as particle (section) with the melt extrusion method.The mean diameter that it is desirable to the polyethylene terephthalate section is generally 2.0-5.0mm, is preferably 2.2-4.0mm.The polyethylene terephthalate section (hereinafter being called " PET section ") that obtains by the liquid phase polycondensation reaction step is an amorphous, and perhaps degree of crystallinity is supplied with pre-crystallisation step with these sections subsequently less than 3%.
Pre-crystallisation step
In that the PET section is heated to the temperature of carrying out solid state polycondensation, as described below in pre-crystallisation step, when perhaps being heated to the temperature a little less than solid state polycondensation, PET grain generation crystallization.More particularly, when carrying out step (A), the PET section is being not less than Tg (second-order transition temperature) and be not higher than 180 ℃ temperature (T
1) heating down, T
1Be preferably 120 to 175 ℃, make the polyethylene terephthalate crystallization, make the degree of crystallinity of polyethylene terephthalate reach 3% or higher.
Vertical or the horizontal whipping appts that agitating vane is equipped with in use carries out step (A).This whipping appts is successive type preferably, adds the PET section at the one end, and discharge section from the other end.
For example, when above-mentioned whipping appts was used for step (A), the PET section added at an end of this device, stirred heating down in the hot gas flow therein, and discharged from the other end of this device.
Step (A) is preferably in the rare gas element carries out.The example of rare gas element comprises nitrogen, argon gas and carbon dioxide.
The PET section is preferably 1 to 20 minute, more preferably 3 to 10 minutes in the time (heat-up time) that step (A) stops.
Carry out step (B) then, wherein heating is left standstill in the PET section and reach (T
Bm-40 ℃), be preferably (T
Bm-30 ℃), (T more preferably
Bm-20 ℃) to T
BmTemperature (T
2), making the polyethylene terephthalate crystallization, degree of crystallinity reaches at least 30%, wherein T
BmThe heat absorption that is defined as the peak-to-peak secondary peak of observed heat absorption when with differential scanning calorimeter (DSC) polyethylene terephthalate being heated with the heating rate of 10 ℃/min begins temperature.
When the heat analysis is carried out in section to PET with DSC, observe endotherm(ic)peak (main peak) at high temperature side, and observe endotherm(ic)peak (secondary peak) with little peak area in the temperature side low than main peak with big peak area.In the present invention, the Heating temperature in the step (B) is that heat absorption by secondary peak begins temperature and definite.
Measure endotherm(ic)peak as follows with DSC.Collect 10mg left and right sides sample (section) from the middle portion of PET section, drying is about 5 hours under the pressure of about 140 ℃ of 5mmHg, is placed in the aluminium dish of holding liquid in the nitrogen.The aluminium disk seal is closed, under following condition determination, measure heat absorption with the DSC-2 type differential scanning calorimeter that Perkin Elmer Co. makes.The speed of sample with 10 ℃/min is begun to heat from room temperature, and to measure endotherm(ic)peak, the heat absorption of the endotherm(ic)peak that obtains recording begins temperature.An example of the DSC curve of polyethylene terephthalate is measured in Fig. 1 explanation with DSC.
(A) is different with step, does not stir in step (B).Therefore can use such as having receptions, heating and discharging the intermittent type device of PET section function, perhaps continous way device, the PET section adds from the one end, and PET section therein leans on gravity mobile in hot gas flow, and discharges from the other end.
Term " heating is left standstill in the PET section " is meant PET not to be cut into slices in heat-processed and forces to stir, comprise that the PET section is mobile in heating unit, and the PET section is not subjected to gravity and moves (flowing) in heating unit.
As Heating temperature (T
2) be higher than T
BmThe time, caking or fusion may take place in the PET section.When Heating temperature is lower than (T
Bm-40 ℃) time, the polyethylene terephthalate crystallization is slow, thereby the pre-crystalline time is long.
After one period heat-up time, promptly along with crystalline carries out, the heat absorption of secondary peak begins temperature (T
Bm) to the high temperature side drift, therefore preferably periodically carry out heat analysis with DSC, and change heating condition according to analytical results.It is desirable to be arranged to raise the gradually Heating temperature of PET section of the heating condition in the step (B).
For intermittent process, be preferably in starting temperature and be about 150 ℃, finishing temperature is about under 190 ℃ the heating condition carries out step (B).For successive processes, be preferably the rate travel of mensuration PET section and the adding speed of hot gas, make inlet temperature be about 150 ℃, temperature out is about 190 ℃.
It is desirable to step (B) with the used identical rare gas element of step (A) in carry out.
The PET section is preferably 30 minutes to 5 hours, more preferably 1 to 3 hour heat-up time (residence time in successive processes) in step (B).
Carry out step (C) then, wherein PET is cut into slices under agitation from said temperature (T
2) be heated to the solid state polycondensation temperature.
Step (C) can with step (A) in carry out in the used identical whipping appts.This whipping appts is continous way preferably, adds the PET section at the one end, and discharges section from the other end.
For example, use above-mentioned whipping appts in the step (C), the PET section adds at an end of device, stirs down and heats in hot gas flow, and discharge from the other end of device.
Step (C) is preferably in the rare gas element same as described above carries out.
PET section residence time (heat-up time) in step (C) is 1 to 20 minute, is preferably 3 to 10 minutes.
By comprising the pre-crystallisation step of step (A) to (C), the polyethylene terephthalate crystallization, its degree of crystallinity is at least 30%, is preferably 45%.Then the solid state polycondensation step is supplied with in pre-crystalline PET section.
The solid state polycondensation step
Solid state polycondensation comprises at least one stage, carries out under the following conditions: temperature is generally 190-230 ℃, is preferably 195-225 ℃; Pressure is generally 1kg/cm
2-G to 10 torr is preferably barometric point to 100 torr; Polymerization reaction time is 1 to 50 hour, is preferably 5 to 20 hours.Solid state polycondensation carries out in such as rare gas elementes such as nitrogen, argon gas or carbon dioxides.In these rare gas elementes, nitrogen preferably.Solid state polycondensation also can carry out under higher temperature decompression.
The limiting viscosity of the polyethylene terephthalate that obtains by solid state polycondensation generally is not less than 0.50dl/g, is not less than 0.54dl/g preferably, better is not less than 0.70dl/g, the best 0.72dl/g that is not less than; Its density generally is not less than 1.37g/cm
3, be not less than 1.38g/cm preferably
3, better be not less than 1.39g/cm
3
Contain oligopolymer (the unitary cyclic trimerization thing of ethylene glycol terephthalate component of above-mentioned formula (I) expression) in the polyethylene terephthalate, its content is no more than 0.6% (weight), be no more than 0.5% (weight) preferably, better be no more than 0.45% (weight), best 0.4% (weight) that is no more than.
The method according to this invention can make the pre-crystallization of polyethylene terephthalate effectively, and can not make PET section caking or fusion.In addition, even, also can easily determine its pre-crystalline condition for the polyethylene terephthalate of copolymerization.
Embodiment
Further describe the present invention with reference to following examples, but should think that the present invention is not subjected to the restriction of these embodiment.
Embodiment 1
The successive polycondensation reaction device comprises first to fourth container type reactor and rotary the 5th reactor of horizontal twin screw, and the polycondensation of ethylene glycol and terephthalic acid is carried out in the following manner continuously with preparation polyethylene terephthalate (PET).
Place the reaction soln of 3,750 weight parts in first reactor in advance, this solution is in nitrogen atmosphere, in 255 ℃ and 1.7kg/cm
2-G stirs down.Highly purified terephthalic acid, ethylene glycol and ANTIMONY TRIOXIDE SB 203 99.8 PCT are mixed, make slurry, this slurry is added first reactor in the following manner continuously to carry out the fs esterification: with the high purity terephthalic acid with per hour 1, the speed of 437 weight parts adds, ethylene glycol is with the per hour speed adding of 645 weight parts, ANTIMONY TRIOXIDE SB 203 99.8 PCT is with the per hour speed adding of 0.57 weight part, during the fs esterification, water is with the speed of 203 weight parts per hour, and ethylene glycol is boiled off with the speed of 3 weight parts per hour.It is 2.0 hours that control fs esterification makes the mean residence time of slurry.Slurry is discharged from first reactor, is introduced continuously in second reactor, remains on 260 ℃ and 0.8kg/cm
2Following and the stirring of-G.
The phosphoric acid with 85% and the homogeneous phase solution of ethylene glycol add second reactor in the following manner continuously: 85% phosphoric acid is with the per hour speed adding of 0.46 weight part, ethylene glycol is with the per hour speed adding of 9 weight parts, simultaneously, water and ethylene glycol respectively with the speed of 84 weight parts per hour and per hour the speed of 7 weight parts boil off continuously, to carry out the subordinate phase esterification, controlling the mean residence time that this reaction makes slurry is 2.0 hours.Slurry is discharged from second reactor, is introduced continuously in the 3rd reactor, remains on 275 ℃ of following and stirrings with 70mmHg.
In the 3rd reactor, ethylene glycol and water respectively with the speed of 62 weight parts per hour and per hour the speed of 6 weight parts boiled off continuously, to carry out the fs polycondensation, controlling the mean residence time that this polycondensation makes reaction mixture is 1.0 hours.Polycondensation product is discharged from the 3rd reactor, is introduced continuously in the 4th reactor, remains on 280 ℃ of following and stirrings with 5mmHg.
In the 4th reactor, ethylene glycol and water respectively with the speed of 26 weight parts per hour and per hour the speed of 3 weight parts boiled off continuously, to carry out the subordinate phase polycondensation, controlling the mean residence time that this polycondensation makes reaction mixture is 1.0 hours.Polycondensation product is discharged from the 4th reactor, is introduced continuously (the rotary reactor of horizontal twin screw) in the 5th reactor, remains on 282-285 ℃ of following and stirring with 1.8-2.5mmHg.
In the 5th reactor, ethylene glycol and water respectively with the speed of 12 weight parts per hour and per hour the speed of 1 weight part boiled off continuously, to carry out the phase III polycondensation, controlling the mean residence time that this polycondensation makes polycondensation product is 2.5 hours.Polycondensation product is pulled out machine (polyesterdrawer) by polyester and is pulled straight with ropy from reactor.Then, will cool off in this ropy immersion water, and use ropy cutting machine (strand cutter) cutting, obtain polyethylene terephthalate (PET) section.
The limiting viscosity that records the polyethylene terephthalate that obtains by above-mentioned liquid phase polycondensation reaction in 25 ℃ of orthomonochlorphenols is 0.58dl/g, and contains the glycol ether unit of 0.95% (weight), and is 1% with the degree of crystallinity that densimetry records.
Then, add the above-mentioned polyethylene terephthalate liquid polycondensation section that obtains in the reaction unit continuously, this reaction unit as shown in Figure 2, comprise horizontal continuous heating container 2, vertical continuous heating container 3, horizontal continuous heating container 4 and solid state polycondensation container 7, to carry out pre-crystallization and solid state polycondensation.Consult Fig. 2, label 1 is meant feed hopper, and label 5 is meant air purifier, and label 6 is meant airheater, and label 8 is meant water cooler, and label 9 is meant the nitrogen purge device, and label 10 is meant gas blower, and label 11 is meant well heater.
Pre-crystalline universal program
In the horizontal continuous heating container 2 of reaction unit, carry out step (A).Add the section of polyethylene terephthalate liquid polycondensation at the one end, under agitation heat then, and discharge from the other end of container.In vertical continuous heating container 3, carry out step (B).To add from its top by the polyethylene terephthalate section of step (A), in nitrogen gas stream, heat then, and discharge from the bottom of this container.In this vertical continuous heating container 3, the polyethylene terephthalate section is moved by gravity.Use horizontal continuous heating container 4 to carry out step (C).To cut into slices by the polyethylene terephthalate of step (B) adds from an end of container 4, under agitation heats then, and discharges from the other end of this container.
To be 1.0% with the degree of crystallinity of method for preparing, temperature be that 50 ℃ polyethylene terephthalate liquid polycondensation section adds from an end of the horizontal continuous heating container 2 that carries out step (A), and under agitation heats in 170 ℃ the temperature, stops 3 minutes.The heat absorption that records the secondary peak of the polyethylene terephthalate that obtains with DSC in step (A) begins temperature (T
Bm) be 175 ℃.The degree of crystallinity that records this polyethylene terephthalate with densimetry is 41%, and the temperature out of the section of step (A) is 170 ℃.
To add in the continuous heating container 3 of vertical plug flow from the polyethylene terephthalate section of step (A) then and carry out step (B), and heating stopped 108 minutes under 170 ℃ temperature.The degree of crystallinity that records the polyethylene terephthalate that obtains with densimetry in step (B) is 48%, T
BmIt is 183 ℃.The temperature out of the section of step (B) is 170 ℃.
To add in the horizontal continuous heating container 4 from the polyethylene terephthalate section of step (B) then and carry out step (C), under agitation heating stopped 125 seconds in 212 ℃ the temperature.The degree of crystallinity that records the polyethylene terephthalate that obtains with densimetry in step (C) is 51%.
The polyethylene terephthalate section that will obtain in above-mentioned pre-crystallisation step was then heated 15 hours in 210 ℃ of nitrogen in solid state polycondensation container 7, to carry out solid state polycondensation.
In above steps, can prepare polyethylene terephthalate, and caking of not cutting into slices and fusion.
Embodiment 2
Prepare polyethylene terephthalate with the method identical, substitute the high purity terephthalic acid of 1,437 weight part except the m-phthalic acid of the high purity terephthalic acid that uses 1,394 weight part and 43 weight parts with embodiment 1; The consumption of ANTIMONY TRIOXIDE SB 203 99.8 PCT changes 0.46 weight part into; The amount of 85% phosphoric acid changes 0.20 weight part into.
In 25 ℃ of limiting viscosities that record the polyethylene terephthalate liquid polycondensation section of gained in orthomonochlorphenol is 0.60dl/g, and contains the glycol ether unit of 0.98% (weight), and recording degree of crystallinity with densimetry is 1%.
Then, make above-mentioned polyethylene terephthalate liquid polycondensation section carry out pre-crystallization, and carry out solid state polycondensation with reaction unit as shown in Figure 2.
With degree of crystallinity is 0.9, and temperature is that 50 ℃ polyethylene terephthalate liquid polycondensation section adds in the horizontal continuous heating container 2 that agitating vane is housed earlier and carries out step (A), this section therein 170 ℃ temperature down heating stopped 2.5 minutes.The heat absorption that records the secondary peak of the polyethylene terephthalate that obtains with DSC in step (A) begins temperature (T
Bm) be 174 ℃.The degree of crystallinity that records this polyethylene terephthalate with densimetry is 39%.The temperature out of the section of step (A) is 165 ℃.These sections are not lumpd in step (A).
To add in the vertical continuous heating container 3 from the polyethylene terephthalate section of step (A) then and carry out step (B), and heating stopped 118 minutes under 170 ℃ temperature, this temperature is lower than heat absorption beginning temperature (T
Bm) 174 ℃.The degree of crystallinity that records the polyethylene terephthalate that obtains with densimetry in step (B) is 45%, T
BmBe 185 ℃, the temperature out of section is 170 ℃.
To add in the horizontal continuous heating container 4 from the polyethylene terephthalate section of step (B) then and carry out step (C), under agitation heating stopped 133 seconds in 212 ℃ the temperature.The degree of crystallinity that records the polyethylene terephthalate that obtains with densimetry in step (C) is 48%, and temperature out is 209 ℃.Caking or fusion do not take place in these sections in step (C).Then these polyethylene terephthalate sections are added in the solid state polycondensation container 7 and carry out solid state polycondensation.In this step, caking or fusion do not take place in these sections yet.
Embodiment 3
The polyethylene terephthalate that will obtain in embodiment 2 steps (A) adds in the continuous heating container 3 of vertical plug flow and carries out step (B), and heating stopped 63 minutes under 170 ℃ temperature, and the heat absorption that this temperature is lower than polyethylene terephthalate begins temperature (T
Bm).The degree of crystallinity that records the polyethylene terephthalate that obtains with densimetry in step (B) is 43%, T
BmBe 179 ℃, the temperature out of section is 170 ℃.
To add in the horizontal continuous heating container 4 from the polyethylene terephthalate section of step (B) then and carry out step (C), under agitation heating stopped 71 seconds in 212 ℃ the temperature.The degree of crystallinity that records the polyethylene terephthalate that obtains with densimetry in step (C) is 49%, and temperature out is 202 ℃.
The polyethylene terephthalate section that will obtain by above-mentioned pre-crystallisation step then is 210 ℃ of heating 15 hours in nitrogen in solid state polycondensation container 7, to carry out solid state polycondensation.
In above steps, can prepare polyethylene terephthalate, and caking or fusion do not take place in these sections.
Reference examples 1
The polyethylene terephthalate liquid polycondensation that uses as shown in Figure 2 reaction unit will use the method identical with embodiment 2 to prepare is cut into slices and is carried out pre-crystallization.
These polyethylene terephthalate liquid polycondensation sections are added the horizontal continuous heating container 2 that agitating vane is housed, carry out step (A), this section is 170 ℃ temperature heating down therein.Stopping will cut into slices after 1 minute takes out from container 2, and the section temperature out is 125 ℃.The heat absorption that records the polyethylene terephthalate that obtains with DSC in step (A) begins temperature (T
Bm) be 160 ℃.The degree of crystallinity that records this polyethylene terephthalate with densimetry is 1.6%.
To add in the vertical continuous heating container 3 from the polyethylene terephthalate section of step (A) then and carry out step (B), and 165 ℃ of heating.Yet these sections are lumpd, and therefore can not carry out following heating steps.
Reference examples 2
The polyethylene terephthalate liquid polycondensation that uses as shown in Figure 2 reaction unit will use the method identical with embodiment 2 to prepare is cut into slices and is carried out pre-crystallization.
These polyethylene terephthalate liquid polycondensation sections are added horizontal continuous heating container 2, carry out step (A), this section is 170 ℃ temperature heating down therein.Stopping will cut into slices after 1.5 minutes takes out from container 2, and the section temperature out is 135 ℃.The heat absorption that records the polyethylene terephthalate that obtains with DSC in step (A) begins temperature (T
Bm) be 168 ℃.The degree of crystallinity that records this polyethylene terephthalate with densimetry is 3%.
Then the polyethylene terephthalate section that makes in the step (A) is added in the vertical continuous heating container 3 and carry out step (B).The Heating temperature of section is 170 ℃ in step (B), and this temperature is higher than heat absorption beginning temperature (T
Bm) 168 ℃, under this temperature, stopped 40 minutes.The degree of crystallinity that records the polyethylene terephthalate that obtains with densimetry in step (B) is 40%.In step (B), these sections are lumpd, and therefore can not carry out following heating steps.
Claims (3)
1. the method for preparing polyethylene terephthalate, the pre-crystallisation step that comprises the section of heating polyethylene terephthalate, this section obtains by step of esterification and liquid phase polycondensation reaction step, so that polyethylene terephthalate crystallization, and the solid state polycondensation step that heats pre-crystalline polyethylene terephthalate section, temperature is reached be higher than pre-crystalline temperature, wherein said pre-crystallisation step comprises:
(A) be not less than Tg and be not higher than 180 ℃ temperature (T
1) heating polyethylene terephthalate section down, stir these sections simultaneously, make the polyethylene terephthalate crystallization, degree of crystallinity reaches at least 3%;
(B) at (T
Bm-40 ℃) to T
BmTemperature (T
2) under, the section of heating polyethylene terephthalate makes it leave standstill simultaneously, makes the polyethylene terephthalate crystallization, and degree of crystallinity reaches at least 30%, wherein T
BmThe heat absorption that is defined as the peak-to-peak secondary peak of observed heat absorption when with differential scanning calorimeter polyethylene terephthalate being heated with the heating rate of 10 ℃/min begins temperature, and final resin temperature is 190 ± 30 ℃, and be 1 to 3 hour heat-up time;
(C) section of heating polyethylene terephthalate with the temperature of these sections that raise, reaches the temperature of solid state polycondensation.
2. the method for preparing polyethylene terephthalate as claimed in claim 1 is characterized in that the solid state polycondensation temperature is 200 ℃ to 230 ℃.
3. the method for preparing polyethylene terephthalate as claimed in claim 1 is characterized in that the heating condition in the step (B) is arranged to begin temperature (T according to the heat absorption of carrying out secondary peak along with crystalline
Bm) to raise the gradually Heating temperature of polyethylene terephthalate section of the ratio of high temperature side drift.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP241688/1996 | 1996-09-12 | ||
| JP241688/96 | 1996-09-12 | ||
| JP24168896 | 1996-09-12 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1176264A CN1176264A (en) | 1998-03-18 |
| CN1136249C true CN1136249C (en) | 2004-01-28 |
Family
ID=17078046
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB971182914A Expired - Fee Related CN1136249C (en) | 1996-09-12 | 1997-09-12 | Process for preparing polyethylene terephthalate |
Country Status (4)
| Country | Link |
|---|---|
| KR (1) | KR100465942B1 (en) |
| CN (1) | CN1136249C (en) |
| ID (1) | ID18263A (en) |
| TW (1) | TW387915B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BRPI0615312A2 (en) * | 2005-09-01 | 2012-12-04 | Mitsubishi Chem Corp | apparatus for heat treatment of polyester particles and multi-stage solid phase polycondensation methods for polyester particles and for the production of a polyester and a polyethylene terephthalate |
| CN101525415B (en) * | 2008-03-04 | 2012-09-05 | 东丽纤维研究所（中国）有限公司 | Polyester for bottle and method for preparing same |
| CN101787114B (en) * | 2010-02-09 | 2011-08-17 | 佛山鸿华聚酯切片有限公司 | Preparation method of special polyester chip for paper industry yarn |
| CN101935394A (en) * | 2010-08-03 | 2011-01-05 | 广东开平春晖股份有限公司 | Preparation method of functional high-viscosity slice for monofilaments |
| CN107987259B (en) * | 2016-10-26 | 2020-05-12 | 中国石油化工股份有限公司 | Modified polyethylene glycol terephthalate and preparation method thereof |
| JP6712040B1 (en) * | 2019-08-19 | 2020-06-17 | 東英通商株式会社 | Polyester resin composition |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2583008B2 (en) * | 1989-03-31 | 1997-02-19 | 三井石油化学工業株式会社 | Method for producing polyethylene terephthalate |
-
1997
- 1997-09-05 TW TW086112839A patent/TW387915B/en not_active IP Right Cessation
- 1997-09-10 KR KR1019970046513A patent/KR100465942B1/en not_active IP Right Cessation
- 1997-09-11 ID IDP973153A patent/ID18263A/en unknown
- 1997-09-12 CN CNB971182914A patent/CN1136249C/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| KR19980024491A (en) | 1998-07-06 |
| KR100465942B1 (en) | 2005-07-12 |
| ID18263A (en) | 1998-03-19 |
| CN1176264A (en) | 1998-03-18 |
| TW387915B (en) | 2000-04-21 |
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