JPH07238157A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To produce a polycarbonate improved in hue by reacting a carbonic diester with a dihydroxyaryl compound in a specified reactor. CONSTITUTION:The surface of a reactor which is made of a stainless steel having an Ni content of 12wt.% or above and a Cr content of 22wt.% or above and is to be brought into contact with the solution is electropolished and then electrolessly plated with Ni or Co. This reactor is charged with a carbonic diester of formula I (wherein Ar is a monovalent aliphatic or aromatic group) and a dihydroxyaryl compound of formula II [wherein A is a 1-15C (halogen- substituted) bivalent hydrocarbon group or a bivalent group such as -S-, -S2-, -SO2-, -SO-, -O-, or -CO-; X is halogen, 1-14C alkyl, 6-18C aryl, 1-8C oxyalkyl, or 6-18C oxyaryl; m is 0 or 1; and y is 0-4). The reaction mixture is subjected to a transesterification reaction in the presence of a catalyst at 120-260 deg.C for 0-5hr, and the resulting ester is polycondensed at 240-320 deg.C in a vacuum of 1mmHg or below.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polycarbonate by a so-called transesterification method. More specifically, the present invention relates to a method for producing a polycarbonate having a good hue using a reaction device in which a surface of a liquid contact portion of a reaction device made of stainless steel is electrolytically polished and then electroless plated.

[0002]

2. Description of the Related Art The so-called transesterification method for producing a polycarbonate by reacting a carbonic acid diester with a dihydroxyaryl compound has a relatively simple process and is superior to the phosgene method (interfacial polymerization method) in terms of operation and cost. It has been recently reviewed from the viewpoint of environmental protection that it can not only exhibit toxic properties, but does not use highly toxic phosgene and halogen-based solvents such as methylene chloride.

However, at present, the transesterification method has not been adopted as a large-scale industrial process. that is,
It is one of the main reasons that the hue of the polycarbonate produced by the conventional transesterification method is inferior to that of the phosgene method polycarbonate. There are various possible causes for the bad hue of the resin, and one of the reasons is that the material of the reactor has a great influence.

In order to solve this problem, for example, in US Pat. No. 4,383,092, the portion which comes into contact with the reaction mixture is made of a nonferrous or nonstainless special material such as tantalum, chromium or nickel. Methods have been proposed for suppressing polymer coloration. However, since these metals are expensive and are not easily processed, they have a drawback of becoming a very expensive reactor.

Japanese Unexamined Patent Publication (Kokai) No. 4-72327 proposes a method of using a metal material having a copper and / or nickel content of 85% by weight or more as a material of a portion which comes into contact with a reaction mixture, but it is also expensive. It has the drawback of being a device.

In addition, in JP-A-5-125168, the content of nickel and / or aluminum is 6%.
0% or more, JP-A-5-125169 has a nickel and / or molybdenum content of 60% or more, and JP-A-5-125170 has a nickel and / or carbon content of 60% or more. No. 125172 has a nickel and / or chromium content of 60% or more, and JP-A-5-125173 has a copper and / or aluminum content of 60% or more.
No. 174 proposes to use a copper and / or zinc content of 60% or more. However, according to the examples, in each case, a special and expensive reaction device for a metallic material is used, and the above problems cannot be solved.

[0007]

In view of the above circumstances, the present invention is directed to a reactor made of a stainless steel material in the production of polycarbonate by a transesterification method without using a reactor made of a special material. It is intended to provide a polycarbonate having an excellent hue by using a surface-treated device.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted a multifaceted study on the influence and effect of the material of the reactor, the treatment method, etc., and as a result, surprisingly, it has been found that the conventional transesterification method produces polycarbonate. It has been discovered that even if the reactor is made of stainless steel, which has been considered unsuitable, a high-quality polycarbonate having an excellent hue can be produced by subjecting the surface of the liquid contact portion to a specific treatment.

That is, according to the present invention, when a carbonic acid diester is reacted with a dihydroxyaryl compound to produce a polycarbonate, the surface of the wetted portion of a reaction apparatus made of a stainless steel material is subjected to electrolytic polishing treatment and then nickel or cobalt. The present invention relates to a method for producing polycarbonate using a reaction device which has been subjected to electroless plating.

Although stainless steel is used as the material of the reactor used in the present invention, stainless steel having a nickel content of 12% by weight or more and a chromium content of 22% by weight or more is particularly preferable. As an example, SUS
-309, SUS-309S (nickel content 12 to 1
5% by weight, chromium content 22 to 24% by weight), SUS-
310, SUS-310S (nickel content 19-22
% By weight, chromium content 24-26% by weight), SUS-3
14 (nickel content 19 to 22% by weight, chromium content 23 to 26% by weight) and the like, but are not limited thereto. In addition, the reactor in which the material of the present invention is used refers to a portion where the reaction mixture and / or the reaction by-product and / or the raw material monomer come into contact,
Examples thereof include, but are not limited to, a polymerization reactor, a fractionating tower, and a raw material monomer dissolving tank.

In the present invention, the electropolishing treatment applied to the surface of the liquid contact portion of the reaction apparatus is a method of electrolyzing a material to be polished as an anode in an electrolytic solution to selectively dissolve microscopic convex portions on the material surface. The electrolytic solution used is not limited as long as it is used for electrolytic polishing of stainless steel, such as phosphoric acid-based, sulfuric acid-based, chromic acid-based, perchloric acid-based, treatment temperature,
The processing time, current density, etc. are not particularly limited.

In the present invention, electroless plating is performed after electropolishing. However, in electroless plating (chemical plating) in the present invention, the material surface is chemically replaced and reduced by the mutual action of metal without using electric energy. In the present invention, plating with nickel or cobalt is applied. Specifically, a method is used in which a salt of nickel or cobalt is used as a plating base material, and an electrolytic polishing treatment-treated reactor surface is brought into contact with an aqueous solution having a bath composition in which a reducing agent and a buffering agent are combined, if necessary.
Although there is no limitation on the chemical concentration, the treatment temperature, the treatment time, etc., it is preferable that the electroless plating is performed immediately after the electrolytic polishing treatment and while the surface is in the active state.

The carbonic acid diester used in the present invention is a compound represented by the following general formula (1).

[Chemical 1]

Examples of the carbonic acid diester represented by the above general formula (1) include diphenyl carbonate and substituted diphenyl carbonate, dimethyl carbonate, ditolyl carbonate, di-t-butyl carbonate and the like, but diphenyl carbonate is particularly preferable. , And substituted diphenyl carbonate. You may use these carbonic acid diesters individually or in mixture of 2 or more types.

Further, with the above-mentioned carbonic acid diester, preferably 50 mol% or less, more preferably 30 mol% or less.
The dicarboxylic acid or dicarboxylic acid ester may be used in an amount of not more than mol%. As such a dicarboxylic acid or dicarboxylic acid ester, terephthalic acid, isophthalic acid, diphenyl terephthalate, diphenyl isophthalate or the like is used. When such carboxylic acid or carboxylic acid ester is used in combination with carbonic acid diester, polyester carbonate is obtained.

The dihydroxyaryl compound used in the present invention is a compound represented by the following general formula (2).

[Chemical 2]

(Where A is 2 having a carbon number of 1 to 15)
Valent hydrocarbon group, a halogen-substituted divalent hydrocarbon group or _{-S -, - S 2 -,} - SO 2 -, - SO -, - O-, and shows a -CO- divalent radicals such as, X represents a halogen atom, an alkyl group having 1 to 14 carbon atoms, an aryl group having 6 to 18 carbon atoms, an oxyalkyl group having 1 to 8 carbon atoms, and an oxyaryl group having 6 to 18 carbon atoms. m is 0 or 1
And y is an integer of 0 to 4)

Examples of the dihydroxyaryl compound represented by the general formula (2) include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3,5-diphenyl) phenyl) propane, 2,2-bis (4-hydroxy-) 3,5-dibromophenyl) propane, 2,2
-Bis (4-hydroxyphenyl) pentane, 2,4 '
-Dihydroxy-diphenylmethane, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-5-nitrophenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 3,3-bis (4-hydroxyphenyl) ) Pentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl)
Sulfone, 2,4'-dihydroxydiphenylsulfone, 5-chloro-2,4'-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) diphenyldisulfone, bis (4-hydroxyphenyl) sulfide, 4,4'-dihydroxydiphenylether , 4,
Examples include 4'-dihydroxy-3,3'-dichlorodiphenyl ether and 4,4'-dihydroxy-2,5-diethoxydiphenyl ether. As these dihydroxyaryl compounds, 2,2-bis (4-hydroxyphenyl) propane is generally used from the viewpoint of availability, but these may be used alone or in combination of two or more. It can be made into a copolymer if necessary.

Although a catalyst is generally used in the reaction of the present invention, the catalyst used is not particularly limited, and a catalyst usually used in the transesterification reaction in the present invention, for example, an alkali metal compound, an alkaline earth compound or boron. A compound, an amine compound, a phosphorus compound or the like can be used. These may be used alone or in combination of two or more. The amount of the catalyst used is usually 0.01 to 3 mol%, preferably 0.05 to 1 mol% based on the dihydroxyaryl compound.

Examples of the alkali metal compound 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 stearate, potassium stearate, lithium stearate, sodium borohydride, lithium borohydride, sodium phenyl borohydride, sodium benzoate, potassium benzoate, lithium benzoate, disodium hydrogen phosphate, phosphoric acid 2 potassium hydrogen, 2 lithium hydrogen phosphate, 2 sodium phenyl phosphate, 2 potassium phenyl phosphate, 2 lithium phenyl phosphate, 2 sodium salt of bisphenol A, 2 potassium salt of bisphenol A, bispheno 2 the lithium salt of A, the sodium salt of phenol, potassium salt of phenol, lithium salt of phenol is exemplified.

Examples of the alkaline earth metal compound include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate and carbonic acid. Examples thereof include magnesium, barium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate.

In addition, examples of the boron-based compound include tetramethylboron, tetraethylboron, tetrapropylboron, tetrabutylboron, trimethylethylboron, trimethylbenzylboron, trimethylphenylboron, triethylmethylboron, triethylbenzylboron, triethylphenyl. Boron, tributylmethylboron, tributylbenzylboron, tributylphenylboron, tetotiphenylboron, benzyltriphenylboron, methyltriphenylboron, butyltriphenylboron, etc., sodium salts, potassium salts, lithium salts, calcium salts, magnesium salts, Barium salt,
Alternatively, strontium salt and the like are exemplified.

Further, amine compounds such as 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 4-hydroxypyridine, 2-methoxypyridine,
4-methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, 4-methylimidazole, aminoquinoline and the like are exemplified.

Examples of phosphorus compounds include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphite and triphenylphosphite.

Of these catalysts, it is practically preferable to use a compound of an alkali metal or an alkaline earth metal because it is inexpensive, and examples of the alkali metal compound include:
Sodium hydroxide, potassium hydroxide, lithium hydroxide,
Sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium stearate,
Potassium stearate, sodium borohydride, as the alkaline earth metal compound, for example, calcium hydroxide, barium hydroxide, magnesium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, calcium carbonate, magnesium carbonate, Barium carbonate, calcium stearate, barium stearate,
Examples include magnesium stearate.

The transesterification reaction is generally carried out in a multi-step process of two or more steps. Specifically, the first stage reaction is carried out at a temperature of 120 to 260 ° C., preferably 180 to 240 ° C. for 0 to 5 hours, preferably 0.5 to 3 hours.
Then increase the reaction temperature while increasing the degree of vacuum of the reaction system,
Finally, under reduced pressure of 1 mmHg or less, 240-320 ℃
The polycondensation reaction is carried out at the temperature of.

The above reaction may be carried out by a batch system, a continuous system or a combination of a batch system and a continuous system, and an apparatus to be used may be a tank system, a tube system or a column system. .

[0028]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. The polycarbonate obtained was evaluated by the following methods.

(1) Molecular Weight (Mv) Using an Ubbelohde viscometer, the intrinsic viscosity [η] at 20 ° C. in methylene chloride was measured and determined from the following formula. [Η] = 1.23 × 10 ⁻⁴ (Mv) ^0.83

(2) Amount of terminal OH Titanium tetrachloride / acetic acid method (Makromol Chem. 88 215 (1965))
Colorimetric determination was carried out by.

(3) Hue Using the obtained polycarbonate, 50 mmφ, 3.
An injection-molded product having a thickness of 0 mm was manufactured, and the YI value was measured using a colorimeter manufactured by Tokyo Denshoku. (The smaller the value, the better the hue)

Example 1 Nickel sulfate hexahydrate immediately after electrolytic polishing treatment of the liquid contact surface of a reactor (reactor main body, stirring blade, stirring shaft) having a capacity of 3 L made of SUS-310S material Thirty
g / l and 15 g of sodium hypophosphite monohydrate
The plating treatment was carried out by immersing in an aqueous solution of 50 liter / liter for 3 minutes.

The reactor which has been subjected to the above treatment is placed in a diphen
1,103 g (5.15 mol) of carbonate, 2,2
-Bis (4-hydroxyphenyl) propane [= bisph
Enol A] 1,142 g (5.00 mol) and hydroxy acid
Sodium iodide 7.50 x 10 ^-6Charge the moles, nitrogen atmosphere
After keeping at 180 ℃ under air for 1 hour, decompression degree is 100m
At the same time as mHg, at a speed of 25K / hr at 280 ° C
The temperature was raised to 280 ° C. and maintained for 2 hours. After the start of temperature rise 2
When the time has passed, the degree of pressure reduction in the reaction vessel is set to 50 mmHg
After the lapse of 1 hour, the degree of pressure reduction is set to 10 mmHg,
30 minutes later, the degree of vacuum is reduced to 1 mmHg or less and
The reaction was carried out under stirring for a total of 7 hours. After the reaction is completed, the bottom of the reactor
Take out the resin and pelletize it with a pelletizer.
It was The obtained polycarbonate has Mv = 22,50.
0, terminal OH = 0.158% by weight, YI value = 1.10
And had a good hue.

Example 2 Immediately after the electrolytic polishing treatment was performed on the surface of the liquid contact portion of the reactor (reactor body, stirring blade, stirring shaft) made of the material of SUS-310S, cobalt sulfate heptahydrate 15 g / liter , Sodium hypophosphite monohydrate 21 g / l, sodium citrate 60 g / l and boric acid 30 g
The plating treatment was carried out by immersing in an aqueous solution of 90 liter / liter for 30 minutes.

Polycarbonate was produced by carrying out the reaction in the same manner as in Example 1 by using the reaction apparatus subjected to the above treatment. The obtained polycarbonate has Mv = 23.0
0, terminal OH = 0.0151% by weight, YI value = 1.12
And had a good hue.

Comparative Example 1 SUS-310 in which only the electrolytic polishing treatment was applied to the surface of the liquid contact portion
Using a reactor made by S, the reaction was carried out in the same manner as in Example 1 to produce a polycarbonate. The obtained polycarbonate has Mv = 22,300 and terminal OH = 0.155.
% By weight and YI value = 1.30.

[0037]

As described above, after the electrolytic polishing treatment is applied to the surface of the wetted portion of the reactor made of stainless steel material,
Polycarbonate having an excellent hue can be produced by using a reaction device which is electrolessly plated with nickel or cobalt, which is an extremely effective method industrially.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masayuki Nakajima 22 Wadai, Tsukuba, Ibaraki Prefecture Mitsubishi Gas Chemical Co., Ltd.

Claims (2)

[Claims] 1. When a polycarbonate is produced by reacting a carbonic acid diester with a dihydroxyaryl compound, the surface of the wetted portion of a reactor made of stainless steel material is subjected to electrolytic polishing treatment, and then electroless nickel or cobalt electrolysis is performed. A method for producing polycarbonate, which comprises using a plated reactor. 2. The method for producing a polycarbonate according to claim 1, wherein the material of the reactor is stainless steel having a nickel content of 12% by weight or more and a chromium content of 22% by weight or more.