JPH04100824A - Production of aromatic polycarbonate - Google Patents

Abstract

PURPOSE:To obtain a discoloration-free high-quality aromatic polycarbonate by polymerizing an aromatic dihydroxy compound with a diaryl carbonate having a chlorine content of a specified value or below and a xanthone content of a specified value or below in the absence of any catalyst. CONSTITUTION:A process for producing an aromatic polycarbonate by reacting an aromatic dihydroxy compound (e.g. bisphenol A) with a diaryl carbonate (e.g. diphenyl carbonate), wherein the reaction is performed in the absence of any polymerization catalyst and the diaryl carbonate has a chlorine content of 0.05ppm or below and a xanthone content of 10ppm or below. According to the above process, a discoloration-free high-quality aromatic polycarbonate can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing aromatic polycarbonate.

(Prior art) In recent years, aromatic polycarbonates have been improved in heat resistance, impact resistance,
It is widely used in many fields as an engineering plasticinox with excellent transparency. Various studies have been conducted on the production method of aromatic polycarbonate, and among them, aromatic dihydroxy compounds such as 22-bis(4-hydroxyphenyl)propane (hereinafter referred to as bisphenol A) and phosgene were used. The interfacial polycondensation method has been industrialized.

However, in this interfacial polycondensation method using phosgene, toxic phosgene must be used;
There were problems such as corrosion of the equipment due to by-produced chlorine-containing compounds such as hydrogen chloride and sodium chloride, and difficulty in separating impurities such as sodium chloride mixed into the resin that adversely affect the physical properties of the polymer.

On the other hand, as a method for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate, for example, a melt method in which bisphenol A and diphenyl carbonate are transesterified in a molten state has been known for a long time. In addition, the present inventors have
In No. 925, after prepolymerizing a dihydroxydiaryl compound and a diaryl carbonate under heating,
A method of crystallization and solid phase polymerization of the crystallization was disclosed.

When carrying out these methods, when diaryl carbonate synthesized by the phosgene method is used as a raw material, contamination of chlorine compounds causes problems in equipment corrosion and physical properties of the polymer, as in the interfacial polycondensation method described above. For example, JP-A-2-175722 describes a method for reducing the hydrolyzable chlorine content of monomers, an aromatic dihydroxy compound and diaryl carbonate, to 3 ppm or less when producing aromatic polycarbonate by a melting method. ing. However, in this invention, since melt polymerization is performed using a transesterification catalyst, it is difficult to avoid coloring of the polymer.

As a method for producing diaryl carbonate, many studies have been conducted on a method of transesterifying dialkyl carbonate in the presence of phenol.
According to No. 52, it is described that in these methods, by-product impurities having a boiling point close to that of the diaryl carbonate are mixed into the diaryl carbonate. Even when aromatic carbonate was produced using diaryl carbonate containing such impurities, there was a problem that the aromatic polycarbonate was colored.

(Problems to be Solved by the Invention) The purpose of the present invention is to overcome the drawbacks of the conventional phosgene method and to obtain high-quality polycarbonate without coloration using an aromatic dihydroxy compound and diaryl carbonate as raw materials. This was done as a.

(Means for Solving the Problems) As a result of intensive studies on a method for producing aromatic polycarbonate using transesterification, the present inventors have found that aromatic polycarbonate can be produced by reacting an aromatic dihydroxy compound with a diaryl carbonate. In manufacturing, ■ No polymerization catalyst is used, and ■ Chlorine content is 0.05p.
ρso or less, and the xanthone content is 10 ppm
It has been discovered that the above-mentioned problems can be achieved by using the following diaryl carbonates, and the present invention has been achieved.

The present invention will be explained in detail below.

In the present invention, the aromatic dihydroxy compound is defined by the formula (
(2): HO-Ar-OH (1) (In the formula, Ar represents a divalent aromatic group.).

The aromatic group ^r is preferably, for example, a divalent carbocyclic or heterocyclic aromatic group having the formula % (wherein Ar' and Ar'' are each independently a divalent carbocyclic or heterocyclic aromatic group each having 5 to 30 carbon atoms). and Y represents a divalent alkane group having 1 to 30 carbon atoms.

In the divalent aromatic group ^r1, Ar'', one or more hydrogen atoms may be substituted with other substituents that do not adversely affect the reaction, such as a halogen atom, an alkyl group having 1 to 10 carbon atoms, or a substituent having 1 to 10 carbon atoms. It may be substituted with 10 alkoxy groups, phenyl/14 groups, phenoxy groups, vinyl groups, cyano groups, ester groups, amide groups, nitro groups, or the like.

Preferred specific examples of the heterocyclic aromatic group used in the present invention include aromatic groups having one or more ring-forming nitrogen atoms, oxygen atoms, or sulfur atoms.

The divalent aromatic group represents, for example, a group such as substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted biphenylene, substituted or unsubstituted pyrylidine. The substituents here are as described above.

A divalent alkane group is, for example, a formula: 5-10 cycloalkyl group, carbocyclic aromatic group with 5-10 ring carbon atoms, 6-10 carbon atoms
represents a carbocyclic aralkyl group, and k represents an integer of 3 to 11. ) is an organic group represented by

Such divalent aromatic groups include, for example, the formula: (wherein R5 and R6 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group, a cycloalkyl group having 5 to 10 ring carbon atoms, or a phenyl group, where m and n are integers of 1 to 4, and when m is 2 to 4, each R5 may be the same or different. or when n is 2 to 4, each R6 may be the same or different.

Furthermore, the divalent aromatic group Ar has the formula %formula% (wherein, Ar' and Ar'' are as described above, and 2 is a bond, or -〇-1-〇〇-1-s--5o2 − −
5o-1COO--CON (R')-, where R1 represents a divalent group as described above. ).

As such a divalent aromatic group, for example, (in the formula,
R5, R6, m and n are as described above. ).

In the prepolymer of the present invention, Ar is 2 as described above.
It may be composed of a single type of valent aromatic group, or it may be composed of two or more types.

Particularly preferred is the case where the group represented by the formula, which is the residue of bisphenol A and substituted bisphenol A, contains 85 to 100 mol% of the total Ar.

Note that the prepolymer of the present invention has approximately 0
．． It may contain a trivalent aromatic group within the range of 01 to 3 mol%.

The diaryl carbonate used in the present invention has the general formula (■): Ar'0COAr' (It ) (wherein Ar
” represents a monovalent aromatic group).

At3 represents a monovalent carbocyclic or heterocyclic aromatic group, but in this Ar', one or more hydrogen atoms are substituted with other substituents that do not adversely affect the reaction, such as a halogen atom, a carbon Alkyl group having 1 to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms, phenyl group, phenoxy group, vinyl group,
It may be substituted with a cyano group, an ester group, an amide group, a nitro group, or the like.

Representative examples of monovalent aromatic group Ar3 include phenyl group,
Examples include naphthyl group, biphenyl group, and pyridyl group. These may be substituted with one or more of the above-mentioned substituents.

As preferable Ar3, for example, Examples include.

Typical examples of diaryl carbonates include (wherein R″ and R8 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, and 1 to 10 carbon atoms;
10, a cycloalkyl group having 5 to 10 ring carbon atoms, or a phenyl group, p and q are integers of 1 to 5, and when p is 2 or more, each R7 is different. Alternatively, when q is 2 or more, each R8 may be different. ) Substituted or unsubstituted diphenyl carbonates can be mentioned.

Among the diphenyl carbonates 1, symmetrical diaryl carbonates such as diphenyl carbonate and lower alkyl-substituted diphenyl carbonates such as ditolyl carbonate and di-t-butylphenyl carbonate are preferred, but diaryl carbonates with the simplest structure are particularly preferred. Diphenyl carbonate is preferred.

These diaryl carbonates i may be used alone or in combination of two or more.

In the present invention, the chlorine content in the diaryl carbonate is Q,05 ppm or less. If the amount of chlorine is more than 0.05 ppm, coloring of the aromatic polycarbonate, especially when exposed to high temperatures for a long time, becomes a problem. Note that chlorine in the present invention refers to chlorine present as an acid or salt such as hydrochloric acid, sodium chloride, or potassium chloride, or chlorine in an organic compound such as phenylchloroformide, and can be determined by potentiometric titration using an AgNO3 solution. It can be quantified by measuring chloride ions using a method.

In the present invention, the amount of xanthone in the diaryl carbonate is 10 ppm or less. As mentioned above, diaryl carbonates synthesized by the transesterification method include compounds with boiling points similar to diaryl carbonates, but among these, diaryl carbonates containing 10 ppm or more of xanthone are particularly used to produce aromatic polycarbonates. It has become clear that when this is done, the resulting aromatic polycarbonate is colored blue-green.

There are no particular restrictions on the method for producing the diaryl carbonate with a chlorine content of 0.05 ppm or less and a xanthone content of 10 ppm or less, which is used in the present invention. Diaryl carbonate synthesized by transesterification with a catalyst can be purified by washing, distillation, etc. to produce it. Chlorine amount 0.05ppn
In order to reduce the concentration to the following minute concentration, the transesterification method is more advantageous than the phosgene method. Catalysts for transesterification are usually (lead compounds) lead oxides such as pbo, pbo□, pb, o4; p
Lead sulfides such as bs, Pb2S; PbC0H)z=
Lead hydroxides such as PbzOz(OH)z NazP
bOz+ KzPbOz, NaHPbO, KHPb0
Namarites such as 2; NazPb03. NaJ
zPbOa, KzPb031 Kz[Pb(OH)i
l, Lpbo,, Ca2Pb04. CaPbO3
Lead salts such as; PbC0z, 2PbCO:+ ・
Carbonates of lead and their basic salts such as Pb(O)l)2; Pb(OCOCHx)z.

Pb (OCOCH3) s , Pb (OCOCH
3) Lead salts of organic acids such as z ・pbo ・3H20, and their carbonates and basic salts; Bu4Ptl+ p
h4pb, Bu3PbC1, Ph*PbBr, Ph5
Pb (or phiPbz) + Bu: +PbOH, p
Organic lead compounds such as h3pbo (Bu is a butyl group, P
h represents a phenyl group), pb(OCHi) 2.
(C)ho)Pb(OPh) , Pb(OPh) z
alkoxyleads such as aryloxylead 11 + P
b-Na+ Pb-Ca+Pb-Ba, Pb-5n,
Lead alloys such as Pb-5b; lead minerals such as marenite and cenanite, and hydrates of these lead compounds; (copper compounds) CuCI, CLIC1z, CuBr, CuBrz
, CuI, Cu1z, Cu(OAC)z, Cu
(acac)z, copper oleate, Bu2Cu, (C
H30) ZCu, AgN0. , AgBr, Hif'
J 7-acid silver, AgC,, H,, Cl0a, Ag (purvalene) JO3+ [to LIC3C-C (CH3
)3]-[CLI(C7H8)C1l, etc. salts and complexes of copper group metals (acac represents an acetylacetone chelate ligand); (alkali metal complexes) Li(acac), Lin (alkali metals such as CJJz) Complexes of: (complexes of zinc) Complexes of zinc such as Zn (acac)2; (complexes of cadmium) Complexes of cadmium such as Cd (acac)2; (compounds of iron group metals) Fe(C+oHs)(Co)s+ Fe(CO)5.
Fe(CJ6)(CO)3. C.

(Meji fshi: z) z (PEtzPh) z, CoC5
Complexes of iron group metals such as F6(Co)t, Ni-g-CsHsNO, ferrocene; (complexes of zirconium) Zr (acac) 41 Complexes of zirconium such as zirconocene; (Lewis acid compounds) AIX:II T]L+ TjX4+ VOX3+V
X5+ ZnX2. Lewis acids such as FeX=, SnX, (where X is a halogen, acetoxy group, alkoxy group, aryloxy group) and transition metal compounds that generate Lewis acids; (organotin compounds) (CH3)3snOcOcH3, (CzHs )3snO
cOc6H3, BuzSnOCOC)13. Pb3S
nOCOCH3, BuzSn(OCOCHs)z, Bu
zSn(OCOC H23)Z, Ph5SnOH3,
(CzHs)3snOPh, BuzSn(OCH3)
Z, BuzSn(OCzHs)z, BuzSn(O
Ph)z, PhzSn(OCHz)z+ (CzHl
)isnOH, Ph5SnOH, BuzSnO, (Cs
L7) zSnO, BuzSnClz, BuSnO(O
Organotin compounds such as Modified by methods such as silylation; etc. are used.

These catalysts may or may not be soluble in the reaction solution under the reaction conditions. Further, these catalysts can be used by being mixed with a compound or carrier that is inert to the reaction, or by being supported on these.

Of course, these catalyst components are organic compounds present in the reaction system, such as aliphatic alcohols, aromatic hydroxy compounds, alkylaryl carbonates 1! , diaryl carbonates, dialkyl carbonates, etc., or may be heat-treated with raw materials or products prior to the reaction.

Among these catalysts, pb is particularly preferably used.
Lead oxides such as o, pbo□, Pb5Oa; Pb
(OH)z.

Lead hydroxides such as Pb2O□(OH)t; PbCO
Lead carbonates and their basic salts such as 3,2PbCOzPb(OH)z; Pb(OCH3)z, (CH3
0) Lead compounds such as alkoxyleads such as Pb(OPh) and Pb(OPh)Z, and aryloxyleads,
Furthermore, those in which these lead compounds have reacted with organic compounds present in the reaction system, or those in which these lead compounds have been heat-treated with raw materials or products prior to the reaction, are also preferably used.

Regardless of which catalyst is used, when the diaryl carbonate obtained by the reaction is purified by distillation, if the purification takes a long time in the presence of the catalyst, xanthone will be produced during the purification. Therefore, especially when using a catalyst that is soluble in the reaction solution, after separating the diaryl carbonate obtained by the reaction from the catalyst in a short time by means such as simple distillation, components with boiling points similar to the diaryl carbonate such as xanthone are separated. A method of purifying is preferred.

In the present invention, as a method for producing an aromatic polycarbonate by reacting an aromatic dihydroxy compound and a diaryl carbonate, a known transesterification method or a solid phase polymerization method described in JP-A-2-180925 may be used. However, it is necessary to use no catalyst. Conventionally known catalysts include alkali metal and alkaline earth metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and calcium hydroxide; lithium hydroxide, sodium hydroxide, and calcium hydroxide; Alkali metal and alkaline earth metal hydroxides such as; alkali metal salts and alkaline earth metal salts of boron and aluminum hydrides such as lithium aluminum hydroxide, sodium boron hydroxide, and tetramethylammonium boron hydroxide; Quaternary ammonium salts; alkoxides of alkali metals and alkaline earth metals such as lithium methoxide, sodium ethoxide, calcium methoxide; lithium phenoxide, sodium phenoxide, magnesium phenoxide, Lio-Ar-0
Li, Na0-Ar-0Na (Ar is an aryl group)
Aryloxides of alkali metals and alkaline earth metals such as; organic acid salts of alkali metals and alkaline earth metals such as lithium acetate, calcium acetate, and sodium benzoate; zinc compounds such as zinc oxide, zinc acetate, and zinc phenoxide. Boron compounds such as boron oxide, boric acid, sodium borate, trimethyl borate, tributyl borate, triphenyl borate; silicon oxide, sodium silicate, tetraalkyl silicon, tetraaryl silicon, diphenyl-ethyl-ethoxy Compounds of silicon such as silicon; compounds of germanium such as germanium oxide, germanium tetrachloride, germanium ethoxide, germanium phenoxide; tin oxide, dialkyltin oxide, diaryltin oxide, dialkyltin carboxylate, tin acetate, ethyltin Tin compounds such as tin compounds bonded with alkoxy or aryloxy groups such as tributoxide, organotin compounds; lead oxide, lead acetate, lead carbonate, basic lead carbonate, alkoxides or aryloxy groups of lead and organic leads; Lead compounds; Onium compounds such as quaternary ammonium salts, quaternary phosphonium salts, and quaternary arsonium salts; Antimony compounds such as antimony oxide and antimony acetate; manganese acetate, manganese carbonate, manganese borate, etc. manganese compounds; titanium compounds such as titanium oxide, titanium alkoxide or aryl oxide;
Examples include zirconium compounds such as zirconium acetate, zirconium oxide, zirconium alkoxides or aryl oxides, and zirconium acetylacetone, and combinations of these can also be used. This is undesirable as it causes the problem of coloring.

(Effect of the invention) In the present invention, when producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate, the amount of chlorine and the amount of xanthone in the diaryl carbonate are kept below a specific value, and the polymerization is carried out without a catalyst. , high quality aromatic polycarbonate without coloration can be obtained.

(Example) Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these Examples.

Note that ■ molecular weight is the number average molecular weight (hereinafter referred to as Mn) measured by gel permeation chromatography (GPC).
).

■The color is determined by the CIELAB method with a test piece thickness of 3.01.
The degree of yellowness was expressed as a b value. Colors other than yellow were visually observed.

■Chlorine content is AgN0. It was determined by potentiometric titration using a solution.

■The xanthone content was determined by liquid chromatography.

For injection molding, ASTM type 4 dumbbells were produced using an MJEC-injection molding machine manufactured by Modern Machinery under conditions of a resin temperature of 300°C and a mold of 90°C.

Example 1 1) Production of methylphenyl carbonate 1.8 kg of dimethyl carbonate, 1°88 kg of phenol, Pb03
0 g was charged into a pressurized reactor equipped with a stirring device, a liquid inlet reaching below the liquid level, a gas outlet, and a gas condenser, and dimethyl carbonate was supplied from the liquid inlet at a rate of 7) cg/Hr. The resulting methanol and dimethyl carbonate are
The reaction was carried out at 13 kg/ctA G and 214°C for 2 hours while extracting the gas from the gas outlet through the gas condenser at a rate of kg/Hr. After 2 hours, 33% against the charged phenol
% yield of methylphenyl carbonate was obtained. From this reaction solution, 0.0% was distilled. 9 kg of methylphenyl carbonate was obtained.

2) Production of diphenyl carbonate The catalyst was pretreated by heating 20 g of PbQ and the amount of methylphecomethylphenyl carbonate at 180°C for 1 hour under a nitrogen stream. Then, 150″C
So 0. 25 g of a pale yellow solid was obtained by distilling off most of the unreacted methylphenyl carbonate and the produced diphenyl carbonate under a reduced pressure of 5 Hg. To this was added 760 g (5 ml) of the methylphenyl carbonate.
0 mol) was added and the entire amount was mixed into a stirrer, a reflux condenser, a vacuum device equipped with a gas inlet that reaches below the liquid level, and a thermometer.
The mixture was transferred to No. 1 reactor. Dry nitrogen 0. The reaction was carried out by immersion in an oil bath at 195° C. under stirring while introducing Bl/min. 90° on the reflux condenser jacket
The reaction was carried out by flowing water from C and distilling off methanol as a by-product, while refluxing methylphenyl carbonate and diphenyl carbonate and returning them to the reactor. 3
After an hour, diphenyl carbonate was obtained with a yield of 90%.

Unreacted methylphenyl carbonate and diphenyl carbonate were distilled out of this reaction solution under reduced pressure of 1 Q Torr, and separated from the catalyst. The distilled reaction solution contained 100 pp- of xanthone based on diphenyl carbonate. The distilled reaction solution was purified under reflux in a 3 m high, 3 inch diameter rectification column filled with a Dixon 6φ to obtain diphenyl carbonate with a xanthone content of 1 ppm. The chlorine content in this diphenyl carbonate was below the detection limit of Q and O of 3 ppm.

3) Production of aromatic polycarbonate 140 g of the diphenyl carbonate, bisphenol A
137g was placed in an actor equipped with a stirring device, gas inlet, and gas suction port, and after repeating vacuum degassing and dry nitrogen introduction several times, the temperature was raised to 180 to 190°C to melt the contents. , vacuum degassing, and dry nitrogen introduction. Then 2
Raise the temperature to 30°C and add 5ON/! of dry nitrogen while stirring! /H
The resulting phenol was distilled out.

After about 50 minutes, the temperature was raised to 260°C, the reaction system was reduced in pressure, and the reaction system was polymerized with 1 mn) Ig for 1 hour to distill out phenol and diphenyl carbonate. As a result,
An aromatic polycarbonate with Mn=7000 was obtained.

When the obtained polycarbonate was crushed and injection molded to produce dumbbells, the BL was 3.9 and no coloration was observed.

Example 2 134 g of diphenyl carbonate obtained in Example 1,
After charging 130 g of bisphenol A into the same reactor as in Example 1 and repeating degassing under reduced pressure and introducing dry nitrogen several times,
After raising the temperature to 180-190"C to melt the contents, degassing under reduced pressure and introducing dry nitrogen were performed. Next, the temperature was raised to 230 °C, and dry nitrogen was introduced at 5 ONj!/Hr while stirring. After about 50 minutes, the reaction system was reduced in pressure and stirred at 2 to 5 mHg for 15 minutes to distill out phenol and diphenyl carbonate.As a result, phenol and diphenyl carbonate were distilled out. An aromatic polycarbonate was obtained, which was taken out from the reactor and
After pulverization, it was immersed in 500 d of acetone for 1 hour to crystallize it. After drying, put it into the reactor again,
When solid phase polymerization was carried out at 210°C for 7 hours under reduced pressure of 2 to 5 wHg and introducing a small amount of dry nitrogen, Mn=
11,000 aromatic polycarbonates were obtained.

When dumbbells were produced by injection molding the obtained polycarbonate, b'' was 3.8 and no coloration was observed.

Examples 3 and 4, Comparative Examples 1 and 2 Diphenyl carbonate was produced in the same manner as in Example 1. However, by changing the rectification conditions, the xanthone content was reduced to 4ppm, 8ppm, 15ppm, 3ppm.
3 ppm of diphenyl carbonate was obtained.

This was polymerized and injection molded in the same manner as in Example 2, and then the color of the dumbbell was evaluated. Table 1 summarizes the results.
Shown below.

Table 1 Aromatic polycarbonate of 9000 was obtained and dumbbells were produced by injection molding. b″ of dumbbell is 4.3
Met.

Comparative Example 4 Using the diphenyl carbonate obtained in Example 1, polymerization was carried out in the same manner as in Example 1 to obtain an aromatic polycarbonate. However, as a polymerization catalyst, boric acid (9), tetramethylammonium hydroxide 15% aqueous solution (91)
(2) 1.3 ■ of sodium hydrogen carbonate was added. The b9 of the dumbbell obtained by injection molding the obtained aromatic polycarbonate was 4°5.

Comparative Example 3 Diphenyl carbonate (Ba
yer) with warm water of 80°C and pH 7,
Diphenyl carbonate with a chlorine content Q of 09 ppm was obtained by distillation under reduced pressure. Using this diphenyl carbonate, Mn (and one other person) was prepared in the same manner as in Example 2.

Claims (1)

[Claims] In producing an aromatic polycarbonate by reacting an aromatic dihydroxy compound and a diaryl carbonate, (1) no polymerization catalyst is used, (2) the chlorine content is 0.05 ppm or less, and,
A method for producing an aromatic polycarbonate, characterized by using diaryl carbonate having a xanthone content of 10 ppm or less.