JP2000070701A - Production of polycarbonate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce polycarbonate of excellent quality without a deteriorated product in the production process of polycarbonate by polymn. condensation of a reaction mixture by providing the passage to feed the reaction mixture with a narrowed and/or widened part having a specified characteristic structure. SOLUTION: As for the narrowed and/or widened part in the passage to feed the reaction mixture, a reducer having 1.6 s Rmax surface roughness as the finished state on the liquid contact part 4 is used, and the reducer is to the connected to pipings at each welded part 5 on the sides to a smaller piping side 2 and a larger piping side 3. The reducer has heat resistance against >=150 deg.C, causes no leak in <=40000×10-6 MPa vacuum degree and has pressure resistance against >=1.0 MPa. The liquid contact part 4 consists of a material having corrosion resistance against the reaction mixture and against monohydroxy compds. produced by the reaction of the reaction mixture. Preferably the reducer has <=20 deg. apex of the narrowed and/or widened part and a smooth surface without steps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polycarbonate resin, and more particularly, to a restriction and / or a flow path provided for feeding a reaction mixture in an apparatus and piping for producing polycarbonate. The present invention relates to a method for producing a polycarbonate resin using a material having a small dead space as a spread portion.

[0002]

2. Description of the Related Art Aromatic polycarbonate resins are excellent in mechanical properties such as impact resistance, heat resistance and transparency, and are widely used as molding materials.

As a method for producing such an aromatic polycarbonate resin, a method of directly reacting an aromatic dihydroxy compound such as bisphenol with phosgene (interface method), or a method of producing an aromatic dihydroxy compound such as bisphenol and an aromatic compound such as diphenyl carbonate is used. There is known a method of transesterifying (melting method) an aromatic carbonate diester. Among such production methods, a method for producing a polycarbonate by a transesterification reaction between an aromatic dihydroxy compound and an aromatic carbonic acid diester includes:
Using a metal organic acid salt, an inorganic acid salt, an oxide, a hydroxide, a hydride or an alcoholate as a catalyst, the reaction temperature is reduced from 150 ° C., which is the minimum temperature required for starting the transesterification reaction, to about 350 ° C. The reaction is carried out by gradually raising the reaction pressure and gradually lowering the reaction pressure from atmospheric pressure to 13.3 × 10 ⁻⁶ MPa, thereby distilling off phenols by-produced from the reaction mixture.

For this reason, the flow path used in the above process is used under high temperature and high vacuum, and the viscosity of the reaction mixture becomes extremely high as the above-mentioned reaction progresses (approaches completion). It depends on the reaction conditions, but usually 2000 Poise to 10000
In order to reach 0 Poise or more, in order to feed the liquid in the flow path, it is necessary to increase the pressure in the flow path in accordance with the resistance (pressure loss) generated in the flow path. Connection between vessel and piping,
It has been necessary to change the flow path diameter in the middle of the flow path due to the connection between the pipes such as a pressure gauge and a thermometer and the pipe, and the relationship between the reaction mixture feed pump and the pressure loss in the pipe.

For these purposes, conventional piping has been
SB 2311-1986, JIS B 2312-
1986, JIS B 2313-1986 and the like have generally used reducers.

[0006] In the present specification, the term "reaction mixture" refers to a mixture mainly containing an aromatic dihydroxy compound (also referred to as an aromatic diol compound) and an aromatic diester carbonate, and a nitrogen-containing basic compound and an alkali metal. In the step of performing a melt polycondensation reaction in the presence of a catalyst such as a transesterification catalyst comprising a compound and / or an alkaline earth metal compound to obtain an aromatic polycarbonate, After reaching a predetermined degree of polymerization, it refers to a mixture in which the polymerization reaction has been stopped, and those in which the degree of polymerization has progressed to some extent are in a state of `` prepolymer '' in general chemical terms, Further advances are those in "chemical terms" in general chemical terms.

[0007]

However, in the above-described reducer which has been conventionally used, depending on the standard such as a large change in the inner diameter of the flow passage, the narrowed and / or widened portion of the flow passage becomes a steep angle, and the reducer portion is reduced. Flow, and the retention and deterioration such as coloring, cross-linking, and gel generation are caused, which has a considerable effect on product quality. In particular, in the case of a constricted and / or widened portion in a horizontal flow passage, an eccentric reducer must be used to prevent air accumulation in the flow passage. The squeezing and / or spreading of the squeezed and / or widened portion became steep, and the effect on product quality was likely to be large.

[0008] The "dead space" mentioned here is
This is a site where fluid renewal is unlikely to occur, and this is a major problem particularly in terms of product quality for a polycarbonate resin which is easily degraded due to retention.

[0009] Particularly in recent years, polycarbonates are DVD, M
It has been used for optical products that require high density and high precision, such as O and CDR. In this case, coloring or gel of polycarbonate is directly used for optical properties such as block error rate of the final product and tensile, bending, toughness. Such a problem has a great influence on the mechanical properties such as, for example, the importance of such a problem is increasing.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a production method for efficiently obtaining a polycarbonate having excellent quality without deterioration.

[0011]

The present invention is as follows. 1. When a reaction mixture containing an aromatic diol compound and a carbonic acid diester compound is polycondensed to produce polycarbonate, heat resistance of 150 ° C. or more is used as a throttle and / or a widening portion of a flow path for sending the reaction mixture. Has a leak amount of substantially zero under a vacuum of 40,000 × 10 ⁻⁶ MPa or less, has a pressure resistance of 0.1 MPa or more, and has a liquid contact portion where the reaction mixture and the reaction mixture react. A material having corrosion resistance to the monohydroxy compound produced by the above method, whose squeezing and / or spreading is 20 ° or less in apex angle and whose surface has no steps and is smooth. A method for producing polycarbonate.

2. 2. The method according to the above item 1, wherein the flow path is a pipe.

3. 3. The method for producing a polycarbonate according to any one of the above items 1 and 2, wherein the narrowed and / or widened portion of the flow path is a reducer.

4. 2. The method according to claim 1, wherein the throttle and / or the widening portion of the flow path is a part of the valve.

[0015] 5. The method according to any one of the above-mentioned items 1, 2, 3, and 4, wherein a flow channel having a surface roughness of the liquid contact portion of 10 μm or less is used.

6. The above-mentioned 1, wherein the channel having corrosion resistance is stainless steel is used.
The production method according to 2, 3, 4 or 5.

[7] 7. The production method according to the above 1, 2, 3, 4, 5, or 6, wherein a flow path having a mechanical finish applied to the liquid contact part is used.

[8] 7. The manufacturing method according to the above 1, 2, 3, 4, 5 or 6, wherein a flow path having a chemical finish applied to the liquid contact part is used.

[0019] In the above item 1, "a narrowed and / or widened portion of a flow path for feeding a reaction mixture has a heat resistance of 150 ° C. or more and 40000 × 10 ^-6.
The leak amount is substantially zero under a vacuum of MPa or less,
It has a pressure resistance of 0.1 MPa or more, and its liquid contact part is made of a material having corrosion resistance to the reaction mixture and a monohydroxy compound generated by the reaction of the reaction mixture, and the squeezing and / or Spread 20 ° apex
The following means that the surface of the flow path for sending the reaction mixture is substantially restricted to at least 150 ° C. 40000 × 10 ^-6 M with heat resistance
The leak amount is substantially zero under a vacuum of not more than Pa,
It has a pressure resistance of 1 MPa or more, and its liquid contact portion is made of a material having corrosion resistance to the reaction mixture and a monohydroxy compound generated by the reaction of the reaction mixture. Apex angle of 20 ° or less, and the surface is smooth with no steps ", 80% or more of the total number of
Desirably, 90% or more has a heat resistance of 150 ° C. or more, has a substantially zero leakage amount under a vacuum of 40,000 × 10 ⁻⁶ MPa or less, has a pressure resistance of 0.1 MPa or more,
The liquid contact part is made of a material having corrosion resistance to the reaction mixture and a monohydroxy compound generated by the reaction of the reaction mixture, and the squeezing and / or spreading is 20 ° or less in apex angle, In addition, the case where the surface is smooth with no steps "is also included. 9
Experiments have confirmed that the effect is significantly reduced at 0% or less, and significantly reduced at 80% or less.

The aromatic polycarbonate referred to in the present invention is a transesterification of a mixture mainly containing an aromatic diol compound and an aromatic carbonic acid diester with a nitrogen-containing basic compound and an alkali metal compound and / or an alkaline earth metal compound. This refers to an aromatic polycarbonate that has been subjected to a melt polycondensation reaction in the presence of a catalyst or the like.

Specific examples of such aromatic diol compounds include bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, and 2,2-bis (4-hydroxy-3). -Methylphenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane, 2,2-bis (4-hydroxy-3,5
-Dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, bis (4-hydroxyphenyl) oxide, bis (3,5
-Dichloro-4-hydroxyphenyl) oxide,
p, p'-dihydroxydiphenyl, 3,3'-dichloro-4,4'-dihydroxydiphenyl, bis (hydroxyphenyl) sulfone, resorcinol, hydroquinone, 1,4-dihydroxy-2,5-dichlorobenzene, 1,4 -Dihydroxy-3-methylbenzene, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide and the like are listed, and 2,2-bis (4-hydroxyphenyl) propane is particularly preferred.

Specific examples of the carbonic acid diester include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl)
Carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate and the like are used. Of these, diphenyl carbonate is particularly preferred.

The polycarbonate of the present invention may further comprise, if necessary, aliphatic diols such as ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,10-decanediol and the like. For example, succinic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, cyclohexanecarboxylic acid, terephthalic acid, etc., and as oxyacids, for example, lactic acid, p-hydroxybenzoic acid, 6
-Hydroxy-2-naphthoic acid may be contained.

The alkali metal compound used as a catalyst includes, for example, hydroxides, bicarbonates, carbonates, acetates, nitrates, nitrites, sulfites, hydrogen cyanide, thiocyanates, stearates of alkali metals. Borohydride, benzoate, hydrogen phosphate, bisphenol, phenol salt and the like.

Specific examples include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate,
Potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium nitrate, potassium nitrate, lithium nitrate, sodium nitrite, potassium nitrite, lithium nitrite, sodium sulfite, potassium sulfite, lithium sulfite, sodium cyanate, potassium cyanate , Lithium cyanate, sodium thiocyanate,
Potassium thiocyanate, lithium thiocyanate, sodium stearate, potassium stearate, lithium stearate, sodium borohydride, potassium borohydride, lithium borohydride, sodium phenylated borate, potassium phenylated borate, phenylated borate Lithium oxide, sodium benzoate, potassium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, bisphenol A
Disodium salt, dipotassium salt, dilithium salt, phenol sodium salt, potassium salt, lithium salt and the like. Among them, bisphenol A disodium salt and phenol sodium salt are preferably used.

The alkali metal compound as a catalyst is preferably used in such a ratio that the alkali metal element in the catalyst is 1 × 10 ^{−8 to} 5 × 10 ⁻⁵ equivalent per mole of the aromatic diol compound. More preferred is 1 × 1 for the same criteria
The ratio is 0 ^-7 to 1 × 10 ^-5 equivalent. If the amount is outside the above range, the properties of the obtained polycarbonate are adversely affected, and the transesterification reaction does not sufficiently proceed to obtain a high-molecular-weight polycarbonate, which is not preferable.

Examples of the nitrogen-containing basic compound as a catalyst include, for example, tetramethylammonium hydroxide (Me ₄ NOH), tetraethylammonium hydroxide (Et ₄ NOH), tetrabutylammonium hydroxide (Bu ₄ NOH), benzyl Ammonium hydroxides having alkyl, aryl, alkylaryl groups such as trimethylammonium hydroxide (φ-CH ₂ (Me) ₃ NOH), hexadecyltrimethylammonium hydroxide, triethylamine, tributylamine, dimethylbenzylamine, hexadecyl Tertiary amines such as dimethylamine, or tetramethylammonium borohydride (Me ₄ NB
H ₄ ), basic salts such as tetrabutylammonium borohydride (Bu ₄ NBH ₄ ), tetrabutylammonium tetraphenylborate (Me ₄ NBPh ₄ ), and tetrabutylammonium tetraphenylborate (Bu ₄ NBPh ₄ ). In particular, tetramethylammonium hydroxide is preferably used.

The nitrogen-containing basic compound is preferably used in such a ratio that the amount of ammonium nitrogen atoms in the nitrogen-containing basic compound is 1 × 10 ^{−5 to} 5 × 10 ⁻⁴ equivalent per 1 mol of the aromatic diol compound. More preferred is a ratio of 2 × 10 ^{−5 to} 5 × 10 ⁻⁴ equivalents to the same standard. Particularly preferred is a ratio of 5 × 10 ^{−5 to} 5 × 10 ⁻⁴ equivalents to the same standard.

In the present invention, if desired, (a) an alkali metal salt of an ate complex of an element of Group 14 of the periodic table or (b) an oxoacid of an element of Group 14 of the Periodic Table Can be used. Here, the elements of Group 14 of the periodic table refer to silicon, germanium, and tin.

The use of these alkali metal compounds as a polycondensation reaction catalyst has the advantage that the polycondensation reaction can be promptly and sufficiently promoted. Further, undesirable side reactions such as a branching reaction generated during the polycondensation reaction can be suppressed to a low level.

(A) As the alkali metal salt of an ate complex of the 14th element of the periodic table, those described in JP-A-7-268091 can be mentioned. Specifically, a compound of germanium (Ge); NaGe (OMe) ₅ , NaGe
(OEt) ₃ , NaGe (OPr) ₅ , NaGe (OB
u) ₅ , NaGe (OPh) ₅ , LiGe (OMe) ₅ ,
LiGe (OBu) ₅ and LiGe (OPh) ₅ can be given.

As a compound of tin (Sn), NaSn
(OMe) ₃ , NaSn (OMe) ₂ (OEt), NaS
n (OPr) ₃ , NaSn (On-C ₆ H ₁₃ ) ₃ , Na
Sn (OMe) ₅ , NaSn (OEt) ₅ , NaSn (O
_{Bu) 5, NaSn (O-} n-C 12 H 25) 5, NaSn
(OEt), NaSn (OPh) ₅ , NaSnBu ₂ (O
Me) ₃ can be mentioned.

(B) Examples of the alkali metal salt of an oxo acid of Group 14 element of the periodic table include silicic acid (silicic acid).
Cic acid), stannic acid (sta)
nicotinic acid, alkali metal salts of germanic acid (germanous acid), germanic acid (germanic acid)
The alkali metal salt of id) can be mentioned as preferable.

The alkali metal salt of silicic acid is, for example, an acidic or neutral alkali metal salt of monosilicic acid (monosilicic acid) or a condensate thereof, and examples thereof include monosodium orthosilicate, disodium orthosilicate, and orthosilicate. Trisodium and tetrasodium orthosilicate can be mentioned.

The alkali metal salt of stannic acid is, for example, an acidic or neutral alkali metal salt of monostannic acid or a condensate thereof, and examples thereof include disodium monostannate (Na ₂ SnO ₃ .CH).
₂ O, x = _0~5), mention may be made of Monosuzu acid tetrasodium salt (Na ₄ SnO _4).

Germanium (II) acid (germanou)
The alkali metal salt of s acid) is, for example, an acidic or neutral alkali metal salt of monogermanic acid or a condensate thereof, and examples thereof include monosodium germanate (NaHGeO ₂ ).

Germanic (IV) acid (germanic)
The alkali metal salt of acid (acid) is, for example, an acidic or neutral alkali metal salt of monogermanic acid (IV) acid or a condensate thereof. Examples thereof include monolithium orthogermanate (LiH ₃ GeO ₄ ) and orthogermanium. Disodium salt, tetrasodium orthogermanate, disodium digermanate (Na
₂ Ge ₂ O ₅ ) and disodium tetragermanate (Na ₂ Ge ₅ O ₁₁ ).

In the above-mentioned polycondensation reaction catalyst, the alkali metal element in the catalyst is 1 × per mole of the aromatic diol compound.
It is preferably used at a ratio of 10 ^{−8 to} 5 × 10 ⁻⁵ equivalent. More preferably, 5 × 10 ⁻⁷ to 1 × with respect to the same standard.
It is a ratio of 10 ^-5 equivalents.

In the above-mentioned polycondensation reaction, at least one cocatalyst selected from the group consisting of an oxo acid of Group 14 element of the periodic table and an oxide of the same element is optionally used together with the above catalyst. Can coexist.

By using these cocatalysts in a specific ratio, the terminal block reaction and the polycondensation reaction rate are not impaired, the branching reaction which is easily generated during the polycondensation reaction, or the foreign matter in the apparatus during the molding process is performed. Undesirable side reactions such as generation and burning can be more effectively suppressed.

As the oxo acid of the 14th element of the periodic table,
For example, silicic acid, stannic acid, and germanic acid can be mentioned.

The oxides of the 14th element of the periodic table include silicon monoxide, silicon dioxide, tin monoxide, tin dioxide,
Mention may be made of germanium monoxide, germanium dioxide and condensates thereof.

The co-catalyst should be present in a proportion such that the metal element of Group 14 of the periodic table in the co-catalyst is not more than 50 mol (atoms) per 1 mol (atom) of the alkali metal element in the polycondensation reaction catalyst. preferable. If the co-catalyst is used in a proportion of more than 50 moles (atoms) of the same metal element, the rate of polycondensation reaction is undesirably reduced.

The cocatalyst is present in such a proportion that the metal element of Group 14 of the periodic table of the cocatalyst is 0.1 to 30 mol (atoms) per 1 mol (atom) of the alkali metal element of the polycondensation reaction catalyst. Is more preferred.

These catalyst systems have the advantage that the polycondensation reaction and the end-capping reaction can be promptly and sufficiently advanced by being used in the polycondensation reaction. Further, undesirable side reactions such as a branching reaction generated in the polycondensation reaction system can be suppressed to a low level.

In the present invention, the temperature and pressure at which the transesterification of the aromatic dihydroxy compound and the carbonic acid diester are not particularly limited, the reaction starts, and the monohydroxy compound produced by the reaction is quickly removed out of the reaction system. Although any conditions may be used as long as the temperature and pressure are set, a temperature of 150 ° C. to 200 ° C. and 40000 × 10
^-6 MPa～13333 after starting the reaction at a pressure of × 10 ^-6 MPa, the reaction temperature increased with increasing molecular weight of the polycarbonate with the progress of the reaction, reducing the reaction pressure,
Finally, a temperature of 270-350 ° C. and 133 × 10
It is common to carry out the reaction at a pressure of ^-6 MPa or less.

More specifically, when the viscosity average molecular weight (Mv) of the polycarbonate is in the range of 1,000 to 2,000, the temperature is 150 to 220 ° C. and the temperature is 40000 × 10 ⁻⁶ MP.
a to carry out the reaction at a pressure of 13333 × 10 ⁻⁶ MPa,
200 to 250 in the region where Mv is 4000 to 6000
C., the reaction was carried out at 1333-13333 × 10 ⁻⁶ MPa, and 250-300 in the region where Mv exceeded 10,000.
The reaction is preferably carried out at a temperature of 133 × 10 ⁻⁶ MPa or lower. The unit of the pressure used is an absolute pressure unless otherwise specified.

A catalyst deactivator can be added to the polycarbonate obtained in the present invention. As the catalyst deactivator used in the present invention, known catalyst deactivators are effectively used, and among these, ammonium salts of sulfonic acids and phosphonium salts are preferable, and furthermore, tetrabutylphosphonium salts of dodecylbenzenesulfonic acid and the like are preferable. The above salts of dodecylbenzenesulfonic acid and the above salts of paratoluenesulfonic acid such as tetrabutylammonium paratoluenesulfonate are preferred. As sulfonic acid esters, methyl benzenesulfonate, ethyl benzenesulfonate, butylbenzenesulfonate, octylbenzenesulfonate, phenylbenzenesulfonate, methyl paratoluenesulfonate, ethyl paratoluenesulfonate, butylparatoluenesulfonate, para Octyl toluenesulfonate, phenyl paratoluenesulfonate and the like are preferably used,
Of these, tetrabutylphosphonium dodecylbenzenesulfonate is most preferably used.

The amount of use of these catalyst deactivators is 0.5 to 50 mol, preferably 0.5 to 50 mol per mol of the polymerization catalyst selected from alkali metal compounds and / or alkaline earth metal compounds. It can be used at a ratio of 10 mol, more preferably at a ratio of 0.8 to 5 mol.

There is no particular limitation on the form of the equipment for carrying out the present invention, and it can be carried out in a batch system or a continuous system. In the case of batchwise operation, usually two reactors are installed in series, the former uses a stirring tank equipped with a rectification tower, and the latter uses a stirring tank without a rectification tower. The reaction is carried out at In this case, the two are connected by a pipe equipped with a valve, and if necessary, the former reaction mixture is transferred to the latter without contact with the outside air using equipment equipped with a pump for transferring the reaction mixture, and the latter is used as desired. It is preferred to carry out the reaction up to the degree of polymerization.

When the reaction is carried out in a continuous system, usually, two or more reactors are installed in series, adjacent reactors are connected by a pipe equipped with a valve, and a pump for transferring the reaction mixture is provided if necessary. By using the equipment provided, the raw materials and the catalyst are continuously supplied to the first reactor while each reactor is maintained under different conditions, and the polycarbonate having a desired degree of polymerization is continuously extracted from the last reactor. Will be implemented.

In such equipment, the flow path plays an important role as a function of supplying the reaction mixture.

According to the studies made by the present inventors, polycarbonate is different from other condensation-polymerized polymers such as polyethylene terephthalate in that it undergoes a long-term heat history even when the influence of oxygen is completely eliminated. It was found that coloring and a deteriorated product called a three-dimensionally crosslinked gel were generated. This degrades the quality of the resulting polycarbonate and causes serious problems especially in applications where high quality is required, for example in optical applications.

In order to solve this problem, it is important to eliminate a stagnant portion called dead space in the equipment. Conventionally, various studies have been made to eliminate the dead space in the reactor, and various proposals have been made. Has been issued. However, it is a reality that the quality of the polycarbonate obtained by the melt polymerization method is still insufficient.

In view of this problem, the present inventors have conducted intensive studies, and as a result, have found that the narrowed and / or widened portion of the flow path, which has not been weighted conventionally, has a large effect on the dead space of the entire equipment. By using a reducer having a specific structure, the quality of a polycarbonate obtained by a melt polymerization method has been greatly improved.

In the present invention, the reducer of the flow path for sending the reaction mixture is, for example, a reducer as shown in FIG.

In the specification of the present application, the term “restriction and / or expansion part of the flow path” means that the cross-sectional area inside a member such as a pipe or a valve through which the reaction mixture flows is reduced.
It means the part that is expanded, and in the case of ordinary piping, it means what is generally called a reducer. However, it is not limited to the reducer specified by JIS, and it is not limited to the reducer specified by JIS. It means a cross section of the entire flow path through which the reaction mixture or the polycarbonate resin passes, such as an inlet portion, a narrowed portion of a strand die, and a flow path portion when the valve is fully opened, and also includes those not generally called reducers.

In the present invention, the term "heat resistance" means that the airtightness and pressure resistance of the flow path exceed the airtightness and pressure required during operation even at a high temperature, and the flow including a throttle and / or a widened portion. It means that there is no problem in use even if a force such as thermal expansion of the material constituting the road itself is received. In the case of producing a polycarbonate resin, it is desirable that the heat-resistant temperature be in the range of 150 to 350 ° C. from the operating conditions.

In the present invention, “40000 × 10 ⁻⁶ M
"The amount of leakage is substantially zero under a vacuum of Pa or less" means that the attained vacuum degree of the flow path including the constricted and / or expanded portion is 13.3 × 10 ⁻⁶ MPa and the constricted and / or expanded portion is used. It means that the amount of gas leaked from the outside including the portion is 120 × 10 ⁻⁶ MPa · L / h or less per 1 L of the internal volume. Specifically, the measurement is performed by appropriately sealing both end portions of the flow path including the throttle and / or the expanding portion.

In this method for measuring the amount of gas leakage, when leakage occurs, it is sometimes difficult to specify the location of the leakage due to the large surface area of the flow path. In some cases, the outside is measured using a halogen leak sensor to identify a leak location. The measuring method is as follows.

A. Gas Leakage Amount Measurement Method The gas leakage amount was measured by suctioning the gas in the flow path with a vacuum pump to a pressure of 13.3 × 10 ⁻⁶ MPa, Is stopped, and one hour later, it is confirmed that the pressure in the flow path is equal to or lower than a predetermined pressure. For example, when the volume in the flow path is 1 L,
One hour after the suction of the vacuum pump was stopped, the test was successful if the pressure in the flow path was 133 × 10 ⁻⁶ MPa or less.

B. Halogen leak test A fluorocarbon 22 is inserted into the flow channel, pressurized to about 0.1 MPa, and a halogen leak sensor is brought close to the outside of the flow channel.
If a halogen is detected, it is identified as a leak location, and if not detected, there is no leak and the test is passed. HAL-7 manufactured by Toshiba can be used as the halogen leak tester.

In order to substantially prevent oxygen in the air from coming into contact with the atmosphere, it is desirable that the portion of the flow passage that makes contact with the atmosphere be an N ₂ gas atmosphere of 98 vol% or more.
In particular, it is more desirably implemented at the joint portion of the pipe.

In the present invention, the term “withstand pressure of 0.1 MPa or more” means that even if the pressure inside the flow path including the constricted portion and / or the expanded portion is a predetermined pressure of 0.1 MPa or more, the flow path is not affected. A state in which no liquid or gas leaks to the outside and there is no problem in use. Usually, the range is the outlet pressure of the pump installed in the flow path and is in the range of 0.1 to 30 MPa.

In the present invention, the phrase "the liquid contact portion is made of a material having corrosion resistance to the raw material compound and the monohydroxy compound produced by the reaction of the compound" means that the constricted and / or widened portion is used. In the use of the flow path including the flow path, any material may be used as long as the function of the flow path is not impaired and the material of the flow path does not substantially elute in the product. Preferably, for example, SUS304, SU
S304L, SUS316, SUS316L, SUS6
30, SCS13, SCS14, SCS16, SCS1
9, stainless steel such as SUS440C, SUS420J2, and SCS2; corrosion-resistant metals such as nickel and titanium; alloys such as inconel, nickel-chromium iron and hastelloy; plating such as HCr and Ni; stellite plating; ceramic coating or HIP (hot static). Carbon steel lined with a hydraulic press) method is preferred. In particular,
Stainless steel is preferred.

In the present invention, the “liquid contact part” is
It refers to a portion where the inside of the flow path including the throttle and / or the widened portion according to the present application comes into contact with the reaction mixture.

In the present invention, “the surface roughness of the liquid contact portion is 1
“0 μ or less” means that Rmax is 10 s or less. Desirably, Rmax is 3.3 s or less.
Speaking of a specific processing method, the buffing is # 200 or more, and the gloss is higher than that of a standard sample without pinholes, residual mill skin, scratches, steps, and exbos. More desirably, Rmax is 1.6 s or less, and in terms of specific processing methods, buffing # 300 or more, mechanical finishing by grinding such as horn finishing, super finishing, lap finishing, liquid honing, and chemical polishing. , Which is processed by electrochemical finishing such as electropolishing and chemical processing. In the present invention, Rmax is JIS B06.
It was measured according to 01-1982.

It is preferable that the flow path including the constricted portion and / or the widened portion is uniformly and uniformly heated by a heat medium jacket, an electric heater or the like. In the case of the heating medium jacket, the throttle and / or / and / or the heating medium jacket are covered with the flow path including the throttle and / or the expanding portion.
Alternatively, it is more preferable to form the channel main body including the widened portion and the heat medium jacket into an integrated structure in terms of uniform heating. If the flow path is relatively large, or if the change in the inner diameter of the flow path due to the constriction and / or widening portion is large, a baffle plate is provided in the heat medium jacket or the number of heat medium flow paths is increased. It is preferred that the heating be uniform. When a flange is used to connect the flow paths, it is desirable to provide a jacket for flowing the heat medium also in the flange.

In the present invention, the flow path is restricted and / or
Alternatively, the connection between the expanded portion and the pipe or the like may be anything as long as it has the same pressure resistance, corrosion resistance, and surface roughness with respect to the liquid contact portion as the throttle and / or the expanded portion. For example, flange, welding, gray rock, and the like. Generally, welding is used.

In the present invention, the flow of the reaction mixture at the entrance of the reaction mixture at the constricted and / or widened portion is preferably smooth so as not to disturb the streamline of the reaction mixture. Particularly preferably, the squeezing angle or the spreading angle of the flow channel is 20 ° or less in apex angle. More preferably, the apex angle is 14 ° or less. Further, those having substantially no step are preferably used. When there is substantially no step, the chamfer at the end is 2 mm or less, more preferably 0.5 mm or less, and still more preferably 0.1 mm or less.
mm or less.

The apex angle in this case is an angle indicated by α in the case of the concentric type as shown in FIGS. 1 and 2, but is β in the case of the eccentric type as shown in FIGS. The angle shown.

In the present invention, when the throttle and / or the expanded portion is used in a horizontal flow path, an eccentric type is often used in order to prevent accumulation of air. In this case, the horizontal flow path refers to a flow path in which the direction in which the reaction mixture flows in the flow path forms an angle of 0 ° to 45 ° with respect to the ground.

Hereinafter, an example of the stop and / or the widening portion according to the present invention will be described with reference to FIGS. However, FIGS. 1, 2, 3, and 4 are only one embodiment of the present invention, and the present invention is not limited by the drawings.

FIGS. 1 and 2 show concentric reducers, and FIGS.
Reference numeral 4 denotes an eccentric reducer. The reducer body 1 shows a state before being welded to the pipe. Liquid contact part 4
Has a surface roughness of 1.6 s in Rmax, and is butt-welded to the pipe at the welded portion 5 on the small pipe side 2 and the large pipe side 3 to be connected.

The welding material used for the welding 5 may be any material having a strength necessary for connecting the pipe and the socket, but TIG welding is preferable. The reducer body 1, the welding material, and the pipe are SUS316. Also, the welded portion has a smooth surface roughness of Rmax of 1.6 s, which disturbs the streamline of the reaction mixture and avoids generation of dead space.

The angle of the stop or the spread is shown in FIGS.
In the concentric type shown in FIG. 2, α = 20 °, and in the eccentric type shown in FIGS. 3 and 4, β = 10 °.

The reaction mixture is continuously transported in the piping including the reducer configured as described above.

The pipe containing the reducer is supplied with a cleaning liquid instead of the reaction mixture when the polycarbonate resin is not manufactured, for example, at the time of washing, at the time of starting up, at the time of manufacturing the polycarbonate resin, or at the time of equipment inspection. In these cases, the function was as good as in the case of the reaction mixture.

[0079]

Embodiments of the present invention will be described below. It should be noted that this embodiment is intended to exemplify the present invention, and the present invention is not limited by this embodiment.

[Example 1] Diphenyl carbonate was charged into a melting tank equipped with a stirrer at a ratio of 1.05 mol to 1 mol of 2,2-bis (4-hydroxyphenyl) propane, followed by purging with nitrogen. Thereafter, the mixture was dissolved at 150 ° C., and the molten mixture was transferred to a raw material storage tank maintained at 150 ° C.

Next, the molten mixture was continuously supplied at a rate of 60 kg / hour to a vertical stirring tank equipped with a rectification column and maintained at an internal temperature of 240 ° C. and an internal pressure of 1333 × 10 ⁻⁶ MPa. To 1 mol of 2,2-bis (4-hydroxyphenyl) propane, 1 × 10 ⁻⁶ equivalent of bisphenol A disodium salt and 1 × 10 ⁻⁴ equivalent of tetramethylammonium hydroxide are continuously added to form The reacted phenol was removed from the rectification column to carry out the reaction.

The obtained reaction mixture was continuously extracted using a gear pump. The polymerization degree of the obtained reaction mixture was determined by measuring the intrinsic viscosity. The intrinsic viscosity [η] is
The reaction mixture was determined by measuring a 0.7 g / dl methylene chloride solution of the reaction mixture using an Ubelod viscometer. As a result, a prepolymer having [η] = 0.16 was obtained.

Next, the prepolymer was continuously supplied to a horizontal reactor having an internal temperature of 270 ° C. and an internal pressure of 133 × 10 ⁻⁶ MPa. By further polymerizing while removing the generated phenol out of the system, a polycarbonate having [η] = 0.35 was continuously obtained.

[0084] The obtained reaction mixture was continuously withdrawn using a gear pump. Outlet side reaction mixture viscosity is 270 ° C
Corresponded to 3000 Poise.

In this example, all the throttles and expansions of the pipes from the dissolving tank to the vertical reaction tank to the gear pump to the horizontal reactor to the gear pump to the removal of the polycarbonate, and all the branch pipes attached to these pipes The reducer of the present invention (the invention corresponding to the description of No. 1 immediately after the item of the means for solving the problem) is adopted.

The pipe used and the reducer according to the present invention are made of SUS316, have a surface roughness of 1.6 s in Rmax due to buffing, and have an apex angle of 10 ° at the constriction and spread. Connect the eccentric reducer with piping and TIG so that the top of the reducer is horizontal.
Used by connecting by welding.

After 10 days of operation, 1 kg of the polymer obtained at the outlet of the horizontal reactor was sampled and 30 μm
After dissolving in methylene chloride with a filter having a mesh opening and filtering, 1 kg of polycarbonate is placed on the filter.
In each case, 5 to 10 foreign substances were detected. The foreign matter mentioned here is a gel, a highly crystallized product, a thermally degraded product, or the like of a polycarbonate resin.

After 40 days of operation, the wetted surface of the reducer was observed with an endoscope. The wetted portion of the reaction mixture maintained almost the metallic luster before the operation.
Upon disassembly and inspection of the squeezed and widened portion of the valve in contact with the liquid, a trace of brown matter was found to adhere.

Example 2 A polymerization reaction was carried out in the same manner as in Example 1 except that the abutting angle and the divergence of the liquid contact part of the gear pump and the valve used were also set to 20 °.

After 10 days of operation, 1 kg of the polymer obtained at the outlet of the horizontal reactor was sampled and 30 μm
After dissolving in methylene chloride with a filter having a mesh opening and filtering, 1 kg of polycarbonate is placed on the filter.
0 to several foreign substances were detected per.

After the operation for 40 days, when the liquid contact surfaces of the gear pump and the valve were observed with an endoscope, the liquid contact portion of the reaction mixture maintained almost the metallic luster before the operation.

[Comparative Example 1] As a reducer used,
The polymerization reaction was carried out in the same manner as in Example 1 except that a concentric reducer having a diaphragm and a spread angle of 45 ° was used.

After 10 days of operation, 1 kg of the polymer obtained at the outlet of the horizontal reactor was sampled, dissolved with methylene chloride through a filter having 30 μm openings, and filtered. About ten foreign substances were detected. This tended to increase with increasing operating time.

After the operation for 40 days, when the reducer was observed with an endoscope, a thin brown substance was attached to the liquid contact surface of the reducer. In addition, the liquid contact surface on the upper side of the reducer adhered more than the liquid contact surface on the lower side, and the spread portion adhered more than the throttle portion.

[0095]

According to the reducer and the flow channel of the present invention having the above-mentioned structure, a dead space is almost eliminated, and a polymer in which retention deterioration such as coloring, crosslinking and gel generation is suppressed can be obtained. Very good results were obtained.

[Brief description of the drawings]

FIG. 1 shows an example of a reducer (concentric type) according to the present invention.

FIG. 2 shows an example of a reducer (concentric type) according to the present invention.

FIG. 3 shows an example of a reducer (eccentric type) according to the present invention.

FIG. 4 shows an example of a reducer (eccentric type) according to the present invention.

[Explanation of symbols]

 1. Reducer body 2. Small piping side 3. Large piping side 4. Liquid contact part 5. welded part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toru Sawaki 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Prefecture Teijin Co., Ltd. Inside the Iwakuni Research Center (72) Inventor Katsuji Sasaki 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Prefecture Teijin Shares F term in the Iwakuni Research Center (reference) 4G075 AA32 BD01 EB21 EE21 FB02 FC06 FC09 FC20 4J029 AA10 AB04 AC01 AE05 KE02 LB04 4J031 CA32 CG02 CG35

Claims (8)

[Claims] When producing a polycarbonate by subjecting a reaction mixture containing an aromatic diol compound and a carbonic acid diester compound to polycondensation, a flow path for feeding the reaction mixture is used as a throttle and / or a widening part.
It has a heat resistance of at least 0 ° C. and a leak amount of substantially zero under a vacuum of 40,000 × 10 ⁻⁶ MPa or less, and 0.1 MPa
It has the above pressure resistance, and its liquid contact part is made of a material having corrosion resistance to the reaction mixture and a monohydroxy compound generated by the reaction of the reaction mixture. The angle is 20 ° or less,
A method for producing polycarbonate, characterized by using a material having a smooth surface with no steps. 2. The method according to claim 1, wherein the flow path is a pipe. 3. The method for producing a polycarbonate according to claim 1, wherein the narrowed and / or widened portion of the flow path is a reducer. 4. The method according to claim 1, wherein the narrowed and / or widened portion of the flow path is a part of the valve. 5. A channel having a surface roughness of a liquid contact portion of 10 μm or less is used.
The manufacturing method as described. 6. A flow path wherein the material having corrosion resistance is stainless steel.
The production method according to 3, 4 or 5. 7. The production method according to claim 1, wherein a flow path having a mechanical finish applied to the liquid contact part is used. 8. The manufacturing method according to claim 1, wherein the liquid contact part is provided with a flow path having a chemical finish.