JPS6162522A - Production of polycondensation product - Google Patents

Abstract

PURPOSE:To obtain a polycondensation product having excellent quality and slight coloring, stably, by carrying out the polycondensation of bisphenol and diaryl carbonate, etc. in three steps while distilling out produced phenol from the system. CONSTITUTION:The objective polycondensation product can be produced in three steps. In the first step, a bisphenol such as 2,2-bis(4'-hydroxyphenyl) propane and a diaryl carbonate and/or a dicarboxylic acid diaryl ester such as diphenyl terephthalate, etc. are subjected to the first-stage polycondensation reaction in the presence of a catalyst such as an alkali metal (carbonate) (e.g. Li), preferably at 50-300 deg.C under 760-1mmHg pressure while distilling out 75-95wt% of the whole phenol to be distilled. In the second step, the product of the first step is extruded in the form of a strand of 1-5mmphi into a vacuum chamber maintained at preferably 240-320 deg.C and 10-0.1mmHg to remove a part of residual phenol by distillation, and in the third step, the phenol is completely distilled out by a twinscrew extruder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing polycondensates by transesterification of bisphenol and diarylcarboxylate and/or diaryl ester of dicarboxylic acid.

[Conventional technology]

Bisphere/-A in the presence of a small amount of transesterification catalyst
The reaction of synthesizing polycarbonate by removing the by-product phenol through transesterification with polydiphenyl carbonate in a molten state is described, for example, in Belgian Patent No. 5.
52543 (1954). Similarly, the reaction of synthesizing polyarylate from bisphenol A and diphenyl terephthalate and diphenyl inphthalate is also known in the Journal of the Japan Society of Textile Science and Technology (P, 56-F, 42, Vol. 2, 1978). The reaction carried out in the molten state is generally carried out in bulk, and in order to quickly distill off the by-product phenol from the reaction mixture, the minimum temperature required for the initiation of transesterification is about 150°C to about 350°C under stirring and mixing. The reaction temperature was gradually raised to ℃, while the reaction pressure was also increased from atmospheric pressure to
Gradually reduce to a certain level. However, as the reaction approaches completion.

Since the viscosity of the reaction mixture becomes extremely high (approximately 10,000 to 100,000 voids or more, depending on the reaction conditions), it becomes difficult to efficiently distill off the by-product phenol, and a special stirring type is required. Therefore, the reaction is carried out in two stages: a pre-polycondensation stage where the viscosity is relatively low and a low molecular weight prepolymer is synthesized under normal stirring conditions, and a post-polycondensation stage where the viscosity is extremely high and a special stirring type is used in the latter half of the reaction. be done. The prepolycondensation step to synthesize the prepolymer is carried out at. For the high viscosity post-polycondensation stage, a batch method using a seed reactor with a special stirring blade shape, or a continuous method using a centrifugal thin film evaporator or pent extruder, etc., has been proposed, but neither method is suitable. It has not yet achieved a satisfactory effect.

[Problem that the invention seeks to solve]

When a seed reactor is used, it is necessary to have a long residence time because the evaporation surface area of the unit throughput machine cannot be large, and as a result, a long thermal history results in highly colored products. Become. When using a centrifugal thin film evaporator, the evaporation surface area per unit throughput can be increased, so the residence time can be shortened, but the polymer may adhere to the rotating shaft, blades, internal bearings, etc.
After a long thermal history, the decomposition products turn black and become mixed into the product. If a single-screw pent extruder is used, polymer will adhere to the screw grooves, resulting in an undesirably colored product.

When using a self-cleaning twin-screw pent type extruder, there is almost no polymer adhesion on the screw part, and no undesirable colored products are produced, but the hold amplifier is small due to the equipment structure, and the unit effective volume machine is The equipment cost for this process is excessive, and there is a limit to scale-up, so it is necessary to shorten the residence time as much as possible, and it is necessary to use stricter conditions for both reaction temperature and degree of vacuum compared to the pre-polycondensation stage. I don't get it. Therefore, the by-product phenol is rapidly distilled off from the pentoline, and the prepolymer accompanies the distilled phenol and adheres to the pentoline. In extreme cases, occlude the pentoline.

[Means for solving problems]

The present invention aims to solve the above-mentioned problems in the post-polycondensation step, and provides a method for stably producing a polycondensate of excellent quality with little coloring.

That is, the present invention provides a method for producing a polycondensate by transesterifying bisphenol and diaryl carbonate and/or diaryl ester, in which a first stage polycondensation reaction is carried out while a mixture of these monomers is melted. 75-95 of the theoretical total distilled phenol
A first-stage polycondensation reaction step in which % by weight of phenol is distilled off, and then the molten first-stage polycondensate is extruded into a vacuum chamber to remove a portion of the remaining phenol, preferably 5 to 10% by weight of the total distilled phenol. % of phenol is distilled off, and then the second stage polycondensate is subjected to a polycondensation reaction in a twin-screw pent-type extruder to reach the remaining several % of the theoretical total distilled phenol. The present invention relates to a method for stably producing a polycondensate with little coloring and excellent quality, characterized by comprising a third polycondensation reaction step in which the polycondensation product is distilled off.

The bisphenol compound used in the present invention is 2.2-
Hx (<'-hydroxyphenyl)propane [bisphenol A], 1,1-bis(4'-hydroxyphenyl)cyclohexane [bisphenol? ], 1,1-bis(4'-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane, 1,2-bis(4'-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)phenylmethane, bis (4-hydroxyphenyl)
Examples include cyclohexylmethane, 3,3'-bis(4'-hydroxyphenyl)pentane, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)2'-thyl, and the like. Bisphenol A is mainly preferred.

Diaryl carbonates include diphenyl carbonate, ditolyl carbonate, and bis(chlorophenyl).
carbonate, cinnatyl carbonate, bis(diphenyl) carbonate, and the like. Diphenyl carbonate is primarily preferred.

Examples of dicarboxylic acid diaryl esters include terephthalic acid diphenyl ester, isophthalic acid diphenyl ester, terephthalic acid-bishydrooxyethyl ester, isophthalic acid-bishydroxyethyl ester, and the like. Mainly preferred are terephthalic acid diphenyl ester and/or isophthalic acid diphenyl ester.

Further, as the catalyst used in the present invention, catalysts generally used in transesterification reactions can be used. Examples of suitable catalysts are listed below.

(1) Alkali metals such as lithium, sodium, calicum, rubidium, cesium, and hexaransium, and carbonates, hydroxides, and hydrides of these alkali metals,
Hydrogenated fluorides, phenolates, bisphenolates, carboxylates, oxides.

(2) Elements of Group π and Group π of the periodic table, such as metals such as calcium, magnesium, and aluminum, and carbonates, hydroxides, hydrides, hydrides, phenolates, and bis of these metals. phenolates, carboxylates,
oxide.

(3) Metal oxides, metal acetates, titanium and tin compounds 1 Metal oxides such as antimony trioxide, germanium oxide, arsenic dioxide, lead oxide, magnesium oxide, zinc oxide, cobalt acetate, zinc acetate, cadmium acetate, Total diabetic acetates such as manganese acetate, titanium compounds such as tetrabutyl titanate, tetraisopropyl titanate, and tetraphenyl titanate, and tin compounds such as dibutyltin oxide, dibutyltin methoxide, and dibutyltin dilaurate.

These catalysts provide effective amounts for conventional transesterification reactions.
Approximately 0.00001-0.1% on bisphenol basis
is used.

The first stage polycondensation reaction step of the present invention is performed at 50 to 300°C.
It is preferable to carry out the reaction under conditions of 60 to 11 Hg.

The second stage polycondensation reaction step of the present invention is to shorten the residence time of the third stage twin-screw pent-type extruder and solve the problem of pent-up.
It may be preheated to 0°C, more preferably 260 to 300°C, and extruded into a strand of 1 to 5 mm in diameter into a vacuum chamber, or it may be connected to a vacuum chamber and flowed down through a 9' tubular heating area into the vacuum chamber. May be extruded. The operating vacuum degree is preferably 10 to 0.
．． 111 Hg, more preferably 1 to 0.1 Hg, but in order to prevent polymer adhesion on the pent line of the twin-screw pent extruder as much as possible, the pent extruder in the third stage polycondensation reaction step It is preferable that the operating vacuum level be the same as that of . The temperature of the third stage heavy curing reaction step is 250 to 350°C.
Vacuum degree 5-0. It is preferable to carry out the test under conditions of lmmHg.

An advantageous embodiment of the invention will be explained with reference to FIG. Bisphenol A in molten state, diphenylcarbo $-),
Diphenyl terephthalate and diphenyl isophthalate are introduced through conduits 4, 5° and 6.7, respectively, into a tank-type stirring cabinet 1 under nitrogen purging. The transesterification initiation temperature is controlled while ensuring sufficient mixing of the reactants. A small amount of transesterification catalyst dissolved in monomer or phenol etc. is then added via conduit 8. Gradually raise the reaction temperature,
In addition, the transesterification reaction is carried out while gradually lowering the operating pressure, and the by-product phenol and some unreacted monomer paper are passed through the distillation column 2 through the conduit 9, and come into contact with the refluxed phenol supplied through the conduit 12. While being rectified, unreacted monomers return to the reactor 1 through conduit 10. The phenol paper passes through conduit 11, is condensed in condenser 3, and is collected through conduit 13. Some phenol is in conduit 12
Some uncondensed phenol is recycled via conduit 1
4 and then collected in a cold trap.

The first stage polycondensation reaction is carried out until 75 to 95% of the total distilled phenol is distilled off, and a prepolymer is synthesized. This prepolymer is then transferred in a molten state via conduit 15 to a hold tank 16 under a N2 purge.

The prepolymer is heat exchanger 1 with a built-in motionless system using a hold tank 16, a cigar bong, etc.
8 and heated to a predetermined temperature. The prepolymer is extruded through a conduit 19 into a flash chamber (7G empty chamber) 20 maintained at a predetermined degree of vacuum in the form of a strand with a diameter of 1 to 5 mm to proceed with the second stage transesterification reaction. .

Distilled phenol is collected through conduit 21.

This second-stage polycondensate is continuously supplied through a conduit 22 to a twin-screw pent-type extruder 23 that is adjusted to almost the same degree of vacuum as the flash chamber 20, and is then continuously supplied to a twin-screw pent-type extruder 23 that is adjusted to almost the same degree of vacuum as the flash chamber 20. After the reaction is completed, the polycondensate product is discharged through conduit 25. Distilled phenol is collected through conduit 24.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 Bisphenol A O, 2 Kf-mol, diphenyl carbonate) 0.108 k-mol, diphenyl terephthalate 0.05 Ky-mol, isophthalic acid diphenyl k O
, 05 Kf-mol was charged into a stirring tank and dissolved at 180° C. after replacing with N2. 0.002 mol of lithium hydroxide was added as a transesterification catalyst, and the temperature was gradually raised to 280°C over about 3 hours, and the degree of vacuum was changed from normal pressure to 1 mlH.
The transesterification reaction was carried out while gradually increasing the concentration to fl, and by-product phenol was continuously distilled off. Then break the vacuum, N
Under normal pressure with 2 purges.

The temperature of the prepolymer was controlled at 280°C. The reduced specific viscosity ηsp/c of the obtained prepolymer measured at 25°C in o, sp/1oo d chloroform was 0.34.
Met.

This prepolymer was supplied to a heat exchanger with a built-in static mixer at a rate of 20 kg/hr using a gear pump, and the temperature was raised to approximately 300°C.
．． It was extruded into a strand shape of 2mm diameter into a vacuum chamber controlled at 7iri+Hg. The prepolymer was heated at 300°C while distilling off by-product phenol.

Intermeshing, counter-rotating twin-screw pent-type extruder controlled at 0.7 mmHg (screw diameter: 106 mm).

FAI silk between screws, screw pitch 34.

Screw rotation speed 2.57 Win, average residence time 6
The final polycondensation reaction was carried out while being extruded by a screw.

The coloring degree Yl value of the obtained product polycondensate (Suga Test Instruments Co., Ltd. direct reading color difference computer 〇DK-OH-1゜measurement was carried out by J
It was carried out in accordance with Engineering 8 Z 8750. ) was 1.15, and the reduced specific viscosity 77ap/c measured at 25°C in chloroform was 0.68.

Comparative Example 1 A prepolymer obtained under the same conditions as Example 1 was heated to 20 pHp in a multitubular heat exchanger equipped with a static mixer.
/hr to raise the temperature to approximately 300°C.
The mixture was charged into the same intermeshing, counter-rotating twin-screw pent-type extruder as in Example 1, which was controlled at 0.7 °C and 0.7 Bg. Approximately 1
Polycondensate adhered to the 0-minute wave pento line, and the degree of vacuum gradually deteriorated, making it impossible to operate.

Comparative Example 2 A prepolymer obtained under the same conditions as Example 1 was used in Example 1.
Intermeshing counter-rotating twin-screw pent-type extruder controlled at 300°C and 0.7 Eg (screw rotation speed 0.57 win, average residence time 2 o min)
was supplied at a rate of 5111/hr.

Although the operation was stable, the coloring degree Y value (measured under the same conditions as in Example 1) of the product polycondensate obtained was 2.64, 0.5 f / 100 lL oo form. 25
The reduced specific viscosity ηs p/c measured at 'C is 0.62
Met.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an advantageous embodiment of the invention. 1... Species stirring tank 2... Distillation column 5... Condenser 4.5, 6.7... Raw material charging conduit 8... Catalyst charging conduit 9.10... Connection with distillation column Connection conduit 11...7 Enol paper conduit 12...Reflux phenol conduit 13...Phenol collection conduit 14...Pent conduit 15...Prepolymer transfer conduit 16...・Hold tank 17...Conduit 1 for transferring prepolymer 18---"ゝ"6 19...Conduit 20 for vacuum chamber preparation...Vacuum chamber 21...Conduit 22 for pent... Conduit 23 for charging the twin-screw pent type extruder...
・Two-screw pent type extruder 24... Conduit for pent 25... Outlet of product polycondensate

Claims (1)

[Claims] 1. In a method for producing a polycondensate by transesterifying bisphenol and diaryl carbonate and/or diaryl dicarboxylic acid ester, a mixture of these monomers is melted and A first stage polycondensation reaction step in which a polycondensation reaction is carried out to distill off 75 to 95% by weight of phenol of the theoretical total distilled phenol, and then this molten first stage polycondensate is extruded into a vacuum chamber. A second stage polycondensation reaction step in which a portion of the residual phenol is distilled off, and then the second stage polycondensate is subjected to a twin-screw pent-type extruder to remove the remaining several percent of the theoretical total distilled phenol. A method for producing a polycondensate, comprising a third stage polycondensation reaction step of distilling it off. 2. The method for producing a polycondensate according to claim 1, wherein the bisphenol is bisphenol A. 3. The method for producing a polycondensate according to claim 1, wherein the diaryl carbonate is diphenyl carbonate. 4. The method for producing a polycondensate according to claim 1, wherein the dicarboxylic acid diaryl ester is diphenyl terephthalate, diphenyl isophthalate, or a mixture thereof.