JP4229506B2 - Method for producing aromatic polycarbonate resin - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an aromatic polycarbonate resin. More specifically, the present invention relates to a method for producing an aromatic polycarbonate resin by a melt polymerization method. The aromatic polycarbonate resin is excellent in hue stability and thermal stability during production, and an aromatic polycarbonate resin excellent in hue and transparency is efficiently obtained. It relates to a method of manufacturing.
[0002]
[Prior art]
Aromatic polycarbonate resins are widely known as very useful resins because they have excellent properties such as impact resistance and transparency. As the method for producing this aromatic polycarbonate resin, an interface method in which an aromatic dihydroxy compound and phosgene are reacted in a mixed solution of an organic solvent and an alkaline aqueous solution, an aromatic dihydroxy compound and a carbonic acid diester, and the presence of a catalyst. There is a melt polycondensation method in which the reaction is carried out under high temperature and reduced pressure to remove the generated phenol out of the system.
[0003]
[Problems to be solved by the invention]
In this melt polycondensation method, an aromatic dihydroxy compound and a carbonic acid diester are used as raw materials. When the carbonic acid diester is handled, it can be used in a molten state at a temperature equal to or higher than its melting point, or can be handled as a powder at a temperature equal to or lower than the melting point. On the other hand, it is known that the aromatic dihydroxy compound is easily decomposed and colored due to its low heat resistance when handled in a molten state at a temperature equal to or higher than its melting point, and thus the hue of the polymer is known to deteriorate.
[0004]
For this reason, when preparing a monomer mixture in melt polycondensation, the molten carbonic acid diester is generally weighed, and the monomeric mixture is prepared by weighing, mixing, and dissolving the powdered aromatic dihydroxy compound therein. Yes.
[0005]
When handling this powdered aromatic dihydroxy compound, the transport atmosphere is usually carried out in a nitrogen atmosphere to prevent dust explosions and to prevent deterioration of the polymer hue due to oxygen present in the powder. .
[0006]
However, even if the powdered aromatic dihydroxy compound is transported under a sufficient nitrogen atmosphere, the hue of the polymer may deteriorate, and in some cases, the polymerization reaction may not proceed.
[0007]
The deterioration of the hue impairs the excellent characteristics of the aromatic polycarbonate resin such as transparency, which is not preferable in terms of product quality particularly when used for optical applications such as a compact disk.
[0008]
Further, the fact that the polymerization reaction does not proceed has a fatal result that an aromatic polycarbonate resin cannot be produced by melt polycondensation.
[0009]
[Means for Solving the Problems]
The present invention is as follows.
1. A blower for transporting a powdered aromatic dihydroxy compound using nitrogen in the production of an aromatic polycarbonate resin by melt polycondensation of a mixture mainly containing a carbonic diester and an aromatic dihydroxy compound in the presence of a catalyst. A method for producing an aromatic polycarbonate resin, wherein a metal having an iron content of 88% by weight or less is used as the material.
2. 2. The method for producing an aromatic polycarbonate resin according to 1 above, wherein a filter having an opening of 5 μm or less is installed on the outlet side of a blower for transporting the powdered aromatic dihydroxy compound using nitrogen.
[0010]
The inventors of the present application have paid attention to the fact that even if the aromatic dihydroxy compound in the powder is transported in a nitrogen atmosphere, there is an adverse effect on the hue and polymerization reactivity of the polymer. It was found that mixing with this aromatic dihydroxy compound deteriorates the hue of the polymer and lowers the polymerization reactivity, thereby completing the present invention.
[0011]
The present invention provides a blower for transporting a powdered aromatic dihydroxy compound using nitrogen in the production of an aromatic polycarbonate resin by melt polycondensation of a carbonic diester and an aromatic dihydroxy compound in the presence of a catalyst. By using a metal having an iron content of 88% by weight or less as the material, an aromatic polycarbonate resin excellent in hue and transparency can be produced.
[0012]
In the present invention, a filter having a mesh opening of 5 μm or less, preferably 1 μm or less, is installed on the outlet side of a blower for transporting powdered aromatic dihydroxy compounds using nitrogen to remove fine iron. An aromatic polycarbonate resin excellent in hue and transparency can be produced.
[0013]
Hereinafter, the manufacturing method of the aromatic polycarbonate resin concerning this invention is demonstrated concretely.
Examples of the aromatic dihydroxy compound used in the present invention 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, -Dichlorobenzene, 1,4-dihydroxy-3-methylbenzene, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide, and the like, particularly 2,2-bis (4-hydroxyphenyl) Propane is preferred.
[0014]
Examples of the carbonic acid diester used in the present invention include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and dicyclohexyl. Carbonate or the like is used. Of these, diphenyl carbonate is particularly preferred.
[0015]
The catalyst used in the present invention is not particularly limited, and examples of the alkali metal compound include alkali metal hydroxides, bicarbonates, carbonates, acetates, nitrates, nitrites, sulfites, cyanates, and thiocyanates. Examples thereof include salts, stearates, borohydrides, benzoates, borohydrides, bisphenols, and phenol salts.
[0016]
Specific examples include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, potassium bicarbonate, lithium bicarbonate, 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, stearin Sodium phosphate, potassium stearate, lithium stearate, sodium borohydride, potassium borohydride, lithium borohydride, phenyl phenyl sodium borate, sodium benzoate, benzo Potassium acid, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium salt of bisphenol A, dipotassium salt, dilithium salt, sodium salt of phenol, potassium salt, lithium salt, etc. Of these, sodium salts of aromatic dihydroxy compounds such as disodium salt of bisphenol A or sodium salts of aromatic monohydroxy compounds such as sodium salt of phenol are preferably used.
[0017]
The alkali metal compound as the catalyst is used in such a ratio that the alkali metal element in the catalyst is 1 × 10 ⁻³ to 1 × 10 ⁻⁸ equivalent per mole of the aromatic dihydroxy compound. Preferably it is used in a ratio of 5 × 10 ⁻⁶ to 1 × 10 ⁻⁸ equivalent, more preferably 5 × 10 ⁻⁶ to 1 × 10 ⁻⁷ equivalent. Deviating from the above-mentioned range is not preferred because there are problems such as adversely affecting various physical properties of the obtained polycarbonate resin, and a high molecular weight polycarbonate resin cannot be obtained because the transesterification reaction does not proceed sufficiently.
[0018]
Examples of the catalyst used in the present invention also include nitrogen-containing basic compounds. For example, tetramethylammonium hydroxide (Me ₄ NOH), tetraethylammonium hydroxide (Et ₄ NOH), tetrabutylammonium hydroxide (Bu ₄ NOH), benzyltrimethylammonium hydroxide (φ-CH ₂ (Me) ₃ NOH), Ammonium hydroxides having alkyl, aryl, alkylaryl groups such as hexadecyltrimethylammonium hydroxide, tertiary amines such as triethylamine, tributylamine, dimethylbenzylamine, hexadecyldimethylamine, or tetramethylammonium borohydride ( Me ₄ NBH _4), tetrabutylammonium borohydride (Bu ₄ NBH _4), tetrabutylammonium tetraphenylborate (Me ₄ NB h _4), can be mentioned basic salts such as tetrabutylammonium tetraphenylborate (Bu ₄ NBPh _4), among others, tetramethyl ammonium hydroxide (Me ₄ NOH) is most preferably used.
[0019]
In the present invention, as desired, as an alkali metal compound of the catalyst, (a) an alkali metal salt of an ate complex of a group 14 element of the periodic table or (b) an alkali metal of an oxo acid of a group 14 element of the periodic table A salt can be used. Here, the element of Group 14 of the periodic table means silicon, germanium, and tin.
[0020]
By using these alkali metal compounds as a polycondensation reaction catalyst, there is an advantage that the polycondensation reaction can be promptly and sufficiently promoted. Moreover, an undesirable side reaction such as a branching reaction generated during the polycondensation reaction can be suppressed to a low level.
[0021]
(A) The alkali metal salt of the art complex of the group 14 element of the periodic rate table is the one described in JP-A-7-268091. Specifically, a germanium (Ge) compound; NaGe (OMe ) ₅ , NaGe (OEt) ₃ , NaGe (OPr) ₅ , NaGe (OBu) ₅ , NaGe (OPh) ₅ , LiGe (OMe) ₅ , LiGe (OBu) ₅ , and LiGe (OPh) ₅ .
[0022]
As the compound of tin (Sn), NaSn (OMe) ₃ , NaSn (OMe) ₂ (OEt), NaSn (OPr) ₃ , NaSn (On-C ₆ H ₁₃ ) ₃ , NaSn (OMe) ₅ , NaSn _{(OEt) 5, NaSn (OBu} ) 5, NaSn (O-n-C 12 H 25) 5, NaSn (OEt), can be exemplified _{NaSn (OPh) 5, NaSnBu 2} (OMe) 3.
[0023]
Further, (b) alkali metal salts of oxo acids of Group 14 elements of the periodic table include, for example, alkali metal salts of silicic acid, alkali metal salts of stannic acid, germanium (II) acid ( Preferred examples include alkali metal salts of germanous acid and alkali metal salts of germanium (IV) acid (germanic acid).
[0024]
The alkali metal salt of silicic acid is, for example, an acidic or neutral alkali metal salt of monosilicic acid or its condensate, and examples thereof include monosodium orthosilicate, disodium orthosilicate, trisodium orthosilicate, Mention may be made of tetrasodium orthosilicate.
[0025]
The alkali metal salt of stannic acid is, for example, an acid or neutral alkali metal salt of monostannic acid or its condensate. Examples thereof include disodium monostannate (Na ₂ SnO ₃ .CH ₂ O, x = 0 to 5), and tetrasodium monostannate (Na ₄ SnO ₄ ).
[0026]
An alkali metal salt of germanium (II) acid is, for example, an acidic or neutral alkali metal salt of monogermanic acid or a condensate thereof, and examples thereof include germanic acid monosodium salt (NaHGeO ₂ ). Can do.
[0027]
The alkali metal salt of germanium (IV) acid is, for example, an acidic or neutral alkali metal salt of monogermanium (IV) acid or a condensate thereof, and examples thereof include orthogermanic acid monolithium acid (LiH _3). GeO ₄ ) orthogermanic acid disodium salt, orthogermanic acid tetrasodium salt, digermanic acid disodium salt (Na ₂ Ge ₂ O ₅ ), tetragermanic acid disodium salt (Na ₂ Ge ₄ O ₉ ), pentagermanic acid and di sodium salt _{(Na 2 Ge 5 O 11)} .
[0028]
The polycondensation reaction catalyst as described above is preferably used in such a ratio that the alkali metal element in the catalyst is 1 × 10 ⁻³ to 1 × 10 ⁻⁸ equivalent per mole of the aromatic dihydroxy compound. More preferable is a ratio of 5 × 10 ⁻⁶ to 1 × 10 ⁻⁸ equivalents with respect to the same standard, and still more preferable is a ratio of 5 × 10 ⁻⁶ to 1 × 10 ⁻⁷ equivalents.
[0029]
In the polycondensation reaction of the present invention, together with the above catalyst, if necessary, at least one cocatalyst selected from the group consisting of an oxo acid of Group 14 element and an oxide of the same element is allowed to coexist. Can do.
[0030]
By using these cocatalysts at a specific ratio, end-blocking reaction, branching reaction that easily occurs during polycondensation reaction without impairing the polycondensation reaction rate, generation of foreign matter in the apparatus during molding, Undesirable side reactions such as burns can be more effectively suppressed.
[0031]
Examples of the oxo acid of Group 14 element of the periodic table include silicic acid, stannic acid, and germanic acid.
[0032]
Examples of the oxide of Group 14 element of the Periodic Table include silicon monoxide, silicon dioxide, tin monoxide, tin dioxide, germanium monoxide, germanium dioxide, and condensates thereof.
[0033]
The cocatalyst is preferably present in a proportion such that the metal element of Group 14 of the periodic table in the cocatalyst is 50 mol (atoms) or less per 1 mol (atom) of the alkali metal element in the polycondensation reaction catalyst. If the co-catalyst is used in a proportion exceeding 50 moles (atoms), the polycondensation reaction rate becomes slow, which is not preferable.
[0034]
The cocatalyst may further be present at a ratio of 0.1 to 30 mol (atom) of the metal element of Group 14 of the periodic table of the cocatalyst per 1 mol (atom) of the alkali metal element of the polycondensation reaction catalyst. preferable.
[0035]
These catalyst systems have an advantage that the polycondensation reaction and the end-capping reaction can be rapidly and sufficiently advanced by using them in the polycondensation reaction. Moreover, an undesirable side reaction such as a branching reaction generated in the polycondensation reaction system can be suppressed to a low level.
[0036]
In the method for producing an aromatic polycarbonate resin according to the present invention, a material having an iron content of 88% by weight or less may be used as a blower material for transporting a powdered aromatic dihydroxy compound in a nitrogen atmosphere. It is preferable for preventing deterioration of the hue of the polymer and preventing a decrease in polymerization reactivity. Examples of such materials include stainless steel and nickel steel. Specifically, SUS304, SUS-304L, SUS316, SUS-316L, SUS630, SCS13, SCS14, SCS16, Hastelloy A, Hastelloy B, Inconel 600, Carpenter 20 , K monel, stellite and the like, and SUS304 and SUS316 are most preferable in consideration of economy.
[0037]
In the method for producing an aromatic polycarbonate resin according to the present invention, it is possible to prevent deterioration of the hue of the polymer by installing a filter having an opening of 5 μm or less on the outlet side of the blower for transporting the powdered aromatic dihydroxy compound, It is preferable to prevent a decrease in polymerization reactivity, more preferably 1 μm or less, and most preferably a filter having an aperture of 0.5 μm or less.
[0038]
【The invention's effect】
According to the present invention, an aromatic polycarbonate resin excellent in hue and transparency can be produced.
[0039]
【Example】
Examples will be described below. In the examples,% and parts are by weight or parts by weight unless otherwise specified. In addition, the physical property of the polycarbonate resin obtained in the following examples was measured as follows.
[0040]
[Color tone (b value)]
Lab values of polycarbonate resin pellets (minor axis x major axis x length (mm) = 2.5 x 3.3 x 3.0) were measured by a reflection method using ND-1001DP manufactured by Nippon Denshoku Industries Co., Ltd., and b value was used as a measure of yellowness. .
[0041]
[Example 1]
Using the following reaction equipment, the melt polycondensation of the aromatic polycarbonate resin was carried out.
The aromatic dihydroxy compound transportation / storage facility is equipped with a rotary valve, a hopper for receiving the powdered aromatic dihydroxy compound from the ton bag, and for transporting the powdered aromatic dihydroxy compound in the hopper to a nitrogen atmosphere. The material is made of SUS304 (iron content is 70.9% by weight) and is equipped with a blower equipped with a 1 μm aperture filter on the outlet side, and a hopper that receives the transported aromatic dihydroxy compound in a nitrogen atmosphere. .
[0042]
For preparing a monomer mixture preparation tank capable of metering in an aromatic dihydroxy compound and a carbonic acid diester, heating and melting and stirring and mixing, a raw material pump capable of continuously supplying raw materials to an initial polymerization tank, and a polymerization catalyst A catalyst preparation tank, a catalyst pump capable of supplying a fixed amount of catalyst solution to the initial polymerization tank, and a polymerization apparatus having a late polymerization tank for further polymerizing the prepolymer obtained in the initial polymerization tank to produce a polymer with a predetermined polymerization degree The melt polycondensation reaction was continuously performed. The aromatic polycarbonate resin exiting the latter polymerization tank was supplied to the biaxial ruder by a gear pump, continuously extruded from a die to form a strand, and then pelletized by a cutter.
[0043]
The initial polymerization tank was provided with a rectifying column equipped with a reflux mechanism for separating the monohydroxy compound generated by the reaction and the carbonic acid diester as a raw material.
The reaction liquid in the initial polymerization tank was continuously supplied to the late polymerization tank by a gear pump.
The latter polymerization tank did not have a rectifying column, and a jacket was attached to the whole.
[0044]
The operating conditions for melt polycondensation are as follows.
Bisphenol A was used as the aromatic dihydroxy compound, and diphenyl carbonate was used as the carbonic acid diester.
[0045]
First, diphenyl carbonate and bisphenol A were supplied to the monomer mixture preparation tank so that the molar ratio of diphenyl carbonate / bisphenol A = 1.01 was obtained by stirring, mixing and dissolving.
[0046]
As the polymerization catalyst, disodium salt of bisphenol A was used. The catalyst was dissolved in a mixed solution of phenol / water = 90/10% by weight so that the catalyst concentration was 30 ppm in the catalyst preparation tank.
[0047]
While continuously supplying the raw material to the first tank, the catalyst solution was supplied so that the disodium salt of bisphenol A was 1 μ equivalent per mole of bisphenol A in the raw material, and continuous melt polycondensation was carried out.
[0048]
The operating conditions of each polymerization tank were as follows: the initial polymerization tank had an internal temperature of 250 ° C. and a degree of vacuum of 30 Torr, and the late stage polymerization tank had a temperature of 270 ° C. and a degree of vacuum of 0.5 Torr.
[0049]
The operation time was 600 continuous hours. A sample of the polycarbonate resin was collected at the outlet of the late polymerization tank at a frequency of once / day and evaluated for quality. The results are shown in Table 1.
[0050]
[Comparative Example 1]
In the apparatus of the example, continuous operation was carried out for 600 hours under the same apparatus and the same operation conditions as in Example 1 except that an iron blower was used as a blower for transporting powdered bisphenol A to nitrogen.
A sample of the polycarbonate resin was collected at the outlet of the late polymerization tank at a frequency of once / day and evaluated for quality. The results are shown in Table 1.
[0051]
[Comparative Example 2]
In the apparatus of the example, an iron blower was used as a blower for transporting powdered bisphenol A to nitrogen, and the filter on the outlet side of the blower was removed, and the apparatus was the same as in Example 1, under the same operating conditions. A continuous operation for hours was carried out.
A sample of the polycarbonate resin was collected at the outlet of the late polymerization tank at a frequency of once / day and evaluated for quality. The results are shown in Table 1.
[0052]
[Table 1]

Claims (2)

A blower for transporting a powdered aromatic dihydroxy compound using nitrogen in the production of an aromatic polycarbonate resin by melt polycondensation of a mixture mainly containing a carbonic diester and an aromatic dihydroxy compound in the presence of a catalyst. A method for producing an aromatic polycarbonate resin, wherein a metal having an iron content of 88% by weight or less is used as the material. 2. The method for producing an aromatic polycarbonate resin according to claim 1, wherein a filter having an opening of 5 [mu] m or less is installed on the outlet side of a blower for transporting the powdered aromatic dihydroxy compound using nitrogen.