JP3544294B2 - Polycarbonate resin with low volatile chlorine and method for producing the same - Google Patents

Description

【００３１】
比較例１〜３
実施例１において、ホスゲン中の塩素含有量を表２に示す濃度に調製した液化ホスゲンを使用し、さらに活性炭塔への通液処理を行うことなく実施した以外は実施例１と同様の操作を行った。
【００３２】
【表２】

【００３３】
【発明の効果】
本発明の揮発性塩素の少ないポリカーボネート樹脂は、常温で保持した際に徐々に揮発する塩素が少なく品質が安定している。
また、本発明の製造方法により得られるポリカーボネート樹脂は、前記の性質に加え、高温成形における熱安定性が著しく向上して、溶融成形後の色相変化が小さく、着色の少ない成形品を得ることができるので、従来品に比べ、その用途範囲を大きく拡大できる利点を有する。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polycarbonate resin having a low volatile chlorine and a method for producing the same. More specifically, the present invention relates to a stable polycarbonate resin having a low amount of volatile chlorine when kept at room temperature and a method for producing the same.
[0002]
[Prior art]
Conventionally, a two-phase interfacial polycondensation method for obtaining a polycarbonate in the presence of an organic solvent by the reaction of an aqueous solution of an alkali metal salt of a diphenol, for example, bisphenol A, with phosgene, and a melt for obtaining a polycarbonate in the absence of an organic solvent In the polycondensation method, many impurities in phosgene used as a raw material have been studied.
Among them, a technique for reducing the order of hundreds of ppm of chlorine contained in phosgene to several tens of ppm is introduced, and it is also proposed that such a technique for reducing the amount of chlorine is good for polycarbonate.
For example, U.S. Pat. No. 3,230,253 and U.S. Pat. No. 3,331,873 disclose a method for adsorbing and removing chlorine contained as an impurity by passing phenols or activated carbon after phosgene production. However, only a technique for simply reducing the amount of chlorine contained in phosgene from the order of several hundred ppm to several tens ppm is introduced. It does not disclose use as a raw material for production. Furthermore, there is no teaching at all regarding the fact that chlorine volatilized at room temperature after molding of the polycarbonate resin has a causal relationship with chlorine contained in the raw material phosgene.
[0003]
On the other hand, JP-A-62-297320 and JP-A-62-297321 contain carbon tetrachloride having a higher boiling point than phosgene as an impurity in phosgene which is a raw material of a resin having a carbonate bond. It has been reported that in order to generate hydrogen chloride by heating during molding of a resin produced using such phosgene as a raw material, the carbon tetrachloride content in phosgene is set to a certain amount or less. I have.
In this case, it discusses hydrogen chloride which is decomposed and generated during heating during molding, and teaches nothing about the phenomenon that chlorine gradually evaporates while being left at room temperature after molding. Absent.
[0004]
Further, phosgene is generally produced by reacting carbon monoxide with chlorine using activated carbon as a catalyst. Since this reaction reaches an equilibrium state in the final stage, if the chlorine content in phosgene is to be reduced, CO / Cl₂The ratio will be shifted in the direction of excess CO. However, a large excess of CO results in a loss of CO gas, and at the same time, an increase in the amount of phosgene discharged as off-gas accompanying the CO gas.
Therefore, in most phosgene plants, it is usual to operate with an excessive amount of CO suppressed to the limit where phosgene loss can be suppressed. As a result, extremely small amounts of chlorine have been neglected due to insufficient measurement means and measurement accuracy.
[0005]
[Problems to be solved by the invention]
The present inventors have conducted intensive studies on volatile chlorine at room temperature from a molded article of polycarbonate obtained as a final product.As a result, surprisingly, the volatile chlorine and impurities in phosgene used as a raw material for producing polycarbonate have been found. It has been found that there is a relationship between the chlorine contained in the steel.
That is, chlorine remaining as an impurity in phosgene is chlorinated in a specific part of the raw material in an initial reaction stage in a polycarbonate production process in some form, remains unchanged until the final process, and is left at room temperature after molding. In the meantime, it was found that chlorine gradually evaporates (detection is recognized as Cl ion).
On the other hand, when carbon tetrachloride as described above remains in the polycarbonate, or when the chloroformate group generated in the polycarbonate production process by the two-phase interfacial polycondensation method remains, the resin is melt-molded. Occurrence of hydrogen chloride is sometimes observed. However, these should be clearly distinguished from chlorine which evaporates after the above-mentioned molding.
That is, in the case of a Cl group having a very high reactivity, it is immediately changed to hydrogen chloride by the heat during melt molding, but in the case of the above-mentioned chlorinated portion, rather than coming off in the melt molding, rather than at room temperature after molding. It was found that chlorine was gradually generated by photolysis or the like below.
Therefore, if carbon tetrachloride remains in the polycarbonate or if the chloroformate group generated during the polycarbonate production process by the two-phase interfacial polycondensation method remains, the molded article is melt-molded. Once removed by washing with pure water.
[0006]
On the other hand, in the case of the site chlorinated by chlorine remaining in the phosgene, chlorine is temporarily generated by applying heat to the polycarbonate during melt molding, but chlorine is temporarily generated. It was found that it was not completely removed, but gradually occurred when left at room temperature (detection was recognized as Cl ions). Such chlorine is called "volatile chlorine".
Although the presence of such volatile chlorine has been often ignored until now, it has been found that it becomes a problem with the recent improvement in quality and physical properties of various polycarbonate resin molded products.
An object of the present invention is to provide a polycarbonate resin having a small amount of volatile chlorine and a method for producing the same.
[0007]
[Means for Solving the Problems]
The present inventors have found that the more chlorine that is contained as an impurity in phosgene is removed as much as possible, the less chlorine that volatilizes when left at room temperature after molding is reduced. Knowing this, the present invention has been completed.
Molecular chlorine contained in phosgene is usually detected by absorbance at a wavelength of 330 nm as described in U.S. Pat. No. 3,230,253 and U.S. Pat. No. 3,331,873, but the lower limit of detection is 10 ppm. In fact, there is no accurate analysis means for a chlorine content of 10 ppm or less.
In this regard, the present inventors have developed COCl containing trace amounts of chlorine as impurities.₂Was collected in a large amount (70 g or more), and when this was absorbed in an aqueous sodium hydroxide solution, only chlorine was changed to NaClO, and it was found that a trace chlorine content could be measured by redox titration.
That is, the polycarbonate resin having a low volatile chlorine of the present invention is characterized in that the amount of chlorine generated by heating when heated at 280 ° C. for 30 minutes and held at room temperature for 3 days is 30 ppb or less. .
Further, another method of the present invention for producing a polycarbonate resin having a low volatile chlorine is a method for producing a resin having a carbonate bond using phosgene as a raw material, wherein the phosgene having a chlorine concentration of 1,000 ppb or less is used as a raw material phosgene. Is used.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
[I] Production of polycarbonate resin with low volatile chlorine
(1) Outline
In the method for producing a carbonate resin having a small amount of volatile chlorine of the present invention, it can be carried out by a method equivalent to a method for producing a resin having a known carbonate bond, and there is no particular limitation, and various production methods using phosgene as a raw material are employed. can do. In this case, the above-mentioned "using phosgene as a raw material" means not only a case where phosgene is used as a direct raw material of the resin, but also a case where the intermediate of the resin is manufactured using phosgene as a raw material and the above-described resin is manufactured using the intermediate It also includes cases such as performing
As a method for producing the resin having a known carbonate bond, usually, when reacting a diphenol and a carbonate raw material to obtain a polycarbonate resin, a carbonate raw material as a carbonate raw material as a carbonate raw material, a phosgene or a phosgene-based carbonate raw material. The method to use. In particular,
1) a method of reacting phosgene and diphenols under interfacial polycondensation conditions or solution polymerization conditions;
2) a method of reacting phosgene with a monohydroxy aromatic compound such as phenol to produce a diaryl carbonate such as diphenyl carbonate, and reacting this with a diphenol under, for example, melt polycondensation conditions;
3) Phosgene is reacted with a monohydric alcohol such as methanol to produce a dialkyl carbonate such as dimethyl carbonate, which is subjected to a transesterification reaction with a monohydroxy aromatic compound such as phenol to produce a diaryl carbonate such as diphenyl carbonate. A method of reacting this with diphenols under, for example, melt polycondensation conditions,
And the like.
[0009]
(2) Raw materials
(A) phosgene
Chlorine concentration
The phosgene used in the method for producing a carbonate resin having a low volatile chlorine of the present invention is in a liquid or gaseous state, and the chlorine concentration in the raw material phosgene is 1,000 ppb or less, preferably 500 ppb or less, more preferably 100 ppb or less. It is particularly important to use those having 0 to 100 ppb.
The phosgene used is usually obtained from the reaction of carbon monoxide with chlorine and contains significant amounts of chlorine.
Examples of the method for keeping chlorine in the raw material phosgene in the above range include adsorption removal of chlorine by an adsorbent such as activated carbon and separation removal by distillation using a boiling point difference, and any method may be used. . However, in the case of distillation removal, the order of removal is an extremely low value, and a considerable number of distillation stages are required. Therefore, adsorption removal using an adsorbent such as activated carbon is more advantageous.
As the adsorbent that can be used in the present invention, in addition to activated carbon, those containing metals such as mercury and antimony, and various types such as zeolite and alumina can be used.In any case, the amount of chlorine in phosgene can be reduced. It is necessary that the above-mentioned predetermined amount can be obtained.
The particle size of these adsorbents is preferably finer, and is usually about 2 mesh sieve, preferably 8 mesh sieve, more preferably 16 mesh sieve, still more preferably about 32 mesh sieve. On the other hand, if the particle size is too small, there is an industrial problem. Therefore, the lower limit is about 60 mesh sieve remaining, and preferably 8 mesh sieve to 60 mesh sieve remaining.
As the activated carbon to be used, activated carbon for acidic gas, activated carbon for basic gas and activated carbon for general gas can be used. Among them, activated carbon for acidic gas having the following physical properties is preferable.
True density: 1.9 to 2.2 g / cc
Porosity: 33-55%
Specific surface area: 700-1500m²/ G
Pore volume: 0.5 to 1.1 cc / g
Average particle size: 12 to 40 angstroms
The particle size of the activated carbon is the same as the particle size range of the adsorbent described above.
Further, from the viewpoint of temperature control, phosgene is preferably in a liquid state, and particularly in the case of adsorption removal, the phosgene is advantageous.
When the reaction is carried out in a liquid state, a reaction pressure capable of maintaining the liquid state at each reaction temperature is selected.
In the present invention, the method of adsorption removal is not particularly limited. For example, the liquefied phosgene is kept in a liquid state in an activated carbon tower, and the space velocity (SV) is usually 2 to 20, preferably 5 to 20, and the temperature is usually 5 to 5. It can be adsorbed and removed by a method of passing the liquid at a temperature of not more than ℃, for example, -5 ℃.
[0010]
(B) Diphenol
The diphenol used in the method for producing a carbonate resin having a low volatile chlorine of the present invention preferably corresponds to the general formula HO-Z-OH. Here, Z is one or more aromatic nuclei, and the hydrogen bonded to the carbon of the nucleus can be replaced by chlorine, bromine, an aliphatic group or an alicyclic group. The plurality of aromatic nuclei may have different substituents. Further, a plurality of aromatic nuclei may be bonded by a cross-linking group. The bridging group includes an aliphatic group, an alicyclic group, a heteroatom, or a combination thereof.
Specifically, hydroquinone, resorcinol, dihydroxydiphenol, bis (hydroxyphenyl) alkane, bis (hydroxyphenyl) cycloalkane, bis (hydroxyphenyl) sulfide, bis (hydroxyphenyl) ether, bis (hydroxyphenyl) ketone, bis (hydroxyphenyl) ketone, (Hydroxyphenyl) sulfone, bis (hydroxyphenyl) sulfoxide, bis (hydroxyphenyl) dialkylbenzene, and derivatives thereof having an alkyl or halogen substituent in the nucleus. Of course, two or more of these diphenols can be used in combination.
These and other suitable diphenols include, for example, U.S. Patent Nos. 4,982,014, 3,028,365, 2,999,835, 3,148, No. 172, No. 3,275,601, No. 2,991,273, No. 3,271,367, No. 3,062,781, No. 2,970,131, and No. 2,999,846, German Patent Publication Nos. 1,570,703, 2,063,050, 2,063,052, and 2,211,956. And French Patent No. 1,561,518.
Particularly preferred diphenols include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) ) Cyclohexane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane. Among them, it is preferable to use 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).
[0011]
(C) Other
In the present invention, an optional chain terminator and / or branching agent can be added as needed when producing the polycarbonate resin.
Chain terminator
Suitable chain terminators include various monophenols, e.g., normal phenols, as well as C-like compounds such as pt-butylphenol and p-cresol.₁~ C₁₀And halogenated phenols such as p-chlorophenol and 2,4,6-tribromophenol. Among these, phenol, cumylphenol, isooctylphenol and pt-butylphenol are preferred chain terminators.
The amount of the chain terminator varies depending on the molecular weight of the desired condensate, but is usually used in an amount of 0.5 to 10% by weight based on the amount of diphenol in the aqueous phase.
[0012]
Branching agent
The branching agent used can be selected from various compounds having three or more functional groups. Suitable branching agents include compounds having three or more phenolic hydroxyl groups, 2,4-bis (4-hydroxyphenyl-isopropyl) phenol, 2,6-bis (2'-hydroxy-5). '-Methylbenzyl) -4-methylphenol, 2- (4-hydroxyphenyl) -2- (2,4-hydroxyphenyl) propane and 1,4-bis (4,4'-dihydroxytriphenylmethyl) benzene included. Further, compounds having three functional groups, 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride, bis (4-hydroxyphenyl) -2-oxo-2,3-dihydroxyindole and 3,3- Bis (4-hydroxy-3-methylphenyl) -2-oxo-2,3-dihydroindole is also included. Among them, those having three or more phenolic hydroxy groups are preferred. The amount of the branching agent used varies depending on the desired degree of branching, but is usually used in an amount of 0.05 to 2 mol% based on the amount of diphenol in the aqueous phase.
[0013]
(3) Polycondensation reaction
(A) Reaction conditions
As described above, as a method for producing a resin having a polycarbonate bond using phosgene as a raw material, typically,
1) a method of reacting phosgene and diphenols under interfacial polycondensation conditions or solution polymerization conditions;
2) a method of reacting phosgene with a monohydroxy aromatic compound such as phenol to produce a diaryl carbonate such as diphenyl carbonate, and reacting this with a diphenol under, for example, melt polycondensation conditions;
3) Phosgene is reacted with a monohydric alcohol such as methanol to produce a dialkyl carbonate such as dimethyl carbonate, which is subjected to a transesterification reaction with a monohydroxy aromatic compound such as phenol to produce a diaryl carbonate such as diphenyl carbonate. A method of reacting this with diphenols under, for example, melt polycondensation conditions,
Can be mentioned.
Hereinafter, an interfacial polycondensation method, which is the most typical production method at present, will be described.
(Interfacial polycondensation method)
Generally, it is a method of reacting diphenols and phosgene in the presence of water and an organic solvent, and usually reacting an alkali metal salt of diphenols and phosgene in an aqueous phase in the presence of an organic solvent. Is the way. The polycarbonate oligomer thus obtained is usually further subjected to a polycondensation reaction to become a high molecular weight polymer.
Solvent
The organic solvent to be used in the present invention is any one that dissolves phosgene and reaction products such as carbonate oligomers and polycarbonates, but does not dissolve water (does not form a homogeneous solution with water) at the reaction temperature and reaction pressure. It is important to include an inert organic solvent.
Representative inert organic solvents include aliphatic hydrocarbons such as hexane and n-heptane, methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, dichloropropane and 1,2-dichloroethylene. Halogenated aliphatic hydrocarbons, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated aromatic hydrocarbons such as chlorobenzene, o-dichlorobenzene and chlorotoluene, and substituted aromatic hydrocarbons such as nitrobenzene and acetophenone Contains hydrogen. Among them, halogenated hydrocarbons such as methylene chloride or chlorobenzene are preferably used.
These inert organic solvents can be used alone or as a mixture with other solvents.
[0014]
However, when chlorobenzene is used alone, it is necessary to use high operating temperatures during the reaction and washing in order to obtain a technically useful concentration of polycarbonate in chlorobenzene.
Also, a suitable solvent combination for industrially important polycarbonates based on 2,2-bis (4-hydroxyphenyl) propane is a mixture of methylene chloride and toluene, if necessary. It can also be used in the method of the invention.
The aqueous phase preferably contains at least three components of water, diphenol and alkali metal hydroxide. In such an aqueous phase, the diphenol reacts with an alkali metal hydroxide, such as sodium hydroxide or potassium hydroxide, to form a water-soluble alkali metal salt. Of course, before contacting with the organic phase, it is preferable to mix the above three components to prepare a uniform aqueous solution and prepare an aqueous phase in advance. Some or all of them can be mixed upon contact with the organic phase.
Amount ratio
The molar ratio of diphenol to alkali metal hydroxide in the aqueous phase is preferably from 1: 1.8 to 1: 3.5, more preferably from 1: 2.0 to 1: 3.2. When preparing such an aqueous solution, the temperature is preferably at least 20 ° C., preferably 30 to 40 ° C. However, if the temperature is too high, diphenol oxidation will occur. Or adding a small amount of a reducing agent such as hydrosulfide.
The preferred amount of phosgene used is affected by the reaction conditions, especially the reaction temperature and the concentration of the diphenol alkali metal salt in the aqueous phase, but is usually 1 to 2 mol, preferably 1.05 mol, per mol of diphenol. １．５1.5 mol. If this ratio is too large, the amount of unreacted phosgene increases and the basic unit deteriorates extremely. On the other hand, if it is too small, the CO group will be insufficient, and proper molecular weight extension will not be performed.
[0015]
(B) catalyst
In the present invention, prior to contact with phosgene, the polycondensation catalyst is supplied at the time of contact between the aqueous phase and the organic phase, and if desired, the supply of the polycondensation catalyst may be performed at the time of contact with phosgene. .
The polycondensation catalyst can be arbitrarily selected from many polycondensation catalysts used in the two-phase interfacial polycondensation method. Among them, trialkylamine, N-ethylpyrrolidone, N-ethylpiperidine, N-ethylmorpholine, N-isopropylpiperidine and N-isopropylmorpholine are suitable, and triethylamine and N-ethylpiperidine are particularly suitable.
[0016]
(C) Production of oligomer
The concentration of the oligomer in the organic phase at the stage of obtaining the oligomer may be within a range in which the obtained oligomer is soluble in the organic phase, and specifically, is about 10 to 40% by weight. The ratio of the organic phase is preferably 0.2 to 1.0 by volume with respect to the aqueous solution of the alkali metal hydroxide of diphenol, that is, the aqueous phase.
The reaction temperature is usually 80 ° C or lower, preferably 60 ° C or lower, more preferably 10 to 50 ° C. If the reaction temperature is too high, it is difficult to control the side reaction, and if it is too low, the refrigerant load increases.
The viscosity average molecular weight (Mv) of the oligomer obtained under such polycondensation conditions is generally about 500 to 10,000, preferably 1600 to 4,500, but is not limited to this molecular weight.
[0017]
(D) Polycondensation reaction
The oligomer thus obtained is converted into a high-molecular polycarbonate under ordinary polycondensation conditions. In a preferred embodiment, the organic phase in which the oligomer is dissolved is separated from the aqueous phase, and if necessary, the above-mentioned inert organic solvent is added to adjust the concentration of the oligomer.
That is, the amount of the solvent is adjusted so that the concentration of the polycarbonate in the organic phase obtained by the polycondensation is 5 to 30% by weight. Thereafter, a water phase containing water and an alkali metal hydroxide is newly added, and in order to further adjust the polycondensation conditions, preferably, the above-mentioned polycondensation catalyst is added, and the desired polycondensation is performed according to the two-phase interfacial polycondensation method. Is completed. The ratio of the organic phase to the aqueous phase during the polycondensation is preferably about 0.2 to 1 in terms of volume ratio: organic phase: aqueous phase = 1: 0.2-1.
After the completion of the polycondensation, a washing treatment is performed with an alkali such as NaOH until the remaining chloroformate group becomes 0.01 μeq / g or less. Thereafter, the organic phase is washed until the electrolyte is exhausted, and finally, the inert organic solvent is appropriately removed from the organic phase, and then the polycarbonate is separated.
[0018]
[II] Polycarbonate resin
The viscosity average molecular weight (Mv) of the polycarbonate resin thus obtained is generally about 10,000 to 100,000, preferably about 12,000 to 35,000.
The viscosity average molecular weight (Mv) is defined as the following formula (ηsp) based on the specific viscosity (ηsp) measured at a temperature of 20 ° C. using a methylene chloride solution having a concentration (C) of 0.6 g / dl of the oligomer or polycarbonate. This is a value calculated using 1) and (2).
ηsp / C = [η] (1 + 0.28ηsp) Equation (1)
[Η] = 1.23 × 10^-5Mv^0.83                      Equation (2)
Further, the polycarbonate thus obtained has a heat-generated chlorine amount (chlorine generation amount per polymer (ppb)) of 30 ppb or less, preferably 20 ppb or less, particularly preferably about 1 to 20 ppb, measured by the method described below. Can be lowered. Therefore, such a polycarbonate resin having a small amount of volatile chlorine has advantages such as being hardly discolored even during molding.
[0019]
Polycarbonate obtained by the method for producing a polycarbonate resin having a low volatile chlorine of the present invention, during the separation of this from the reactor, or before processing it, or during that time, various additives, for example, stable An effective amount of an agent, a mold release agent, a flame retardant, an antistatic agent, a filler, a fiber, an impact strength modifier and the like can be added.
[0020]
[III] Applications
These polycarbonates can be processed into various molded articles, for example, films, yarns, plates, etc., by injection molding, extrusion molding, etc., and in various technical fields such as electric parts or the building industry, and for lighting equipment. Used for materials and optical equipment materials, especially lamp housings, optical lenses, optical discs and audio discs. In particular, when used in electric and electronic containers, this volatile chlorine as an impurity is disliked, so that a polycarbonate resin having a small amount of volatile chlorine is extremely useful.
The molded article of polycarbonate obtained by the present invention not only has excellent physical properties unique to polycarbonate, but also has a significantly improved thermal stability in high-temperature molding, a small change in hue after melt molding, and a molded article with little coloring. Since it can be obtained, there is an advantage that its application range can be greatly expanded as compared with conventional products.
[0021]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist.
[I] Preparation of phosgene
The raw material liquefied phosgene was charged into an activated carbon tower filled with activated carbon for acidic gas having the following physical properties (manufactured by Takeda, trade name: Shirasagi GH2X4 / 6UG) in a cylindrical container having a diameter of 55 mm and a height of 500 mm at −5 ° C. and 7.2 kg. The solution was passed at a space velocity (SV) of 4 per hour.
By repeating this liquid passing treatment, the chlorine content in the liquefied phosgene at the outlet of the activated carbon tower was reduced to 0 ppb.
The chlorine content in phosgene before the activated carbon treatment shown in Tables 1 and 2 was calculated by adding chlorine gas to the liquefied phosgene whose chlorine content was reduced to 0 ppb by performing the above-mentioned liquid passing treatment. The concentration of chlorine gas was adjusted by adding it.
Further, the chlorine content in phosgene after the activated carbon treatment shown in Table 1 is a value after the liquefied phosgene whose concentration has been adjusted is further passed through an activated carbon tower.
Physical properties of activated carbon for acid gas
Particle size: 4 mesh sieve passed to 6 mesh sieve residue
Degree of vacuum: 2.1 g / cc
Porosity: 40%
Specific surface area: 1200m²/ G
Pore volume: 0.86 cc / g
Average pore size: 12 angstroms
[0022]
[II] Production of polycarbonate resin
Examples 1 to 5
After dissolving 15.09 kg / hr of bisphenol A (BPA), 5.49 kg / hr of sodium hydroxide (NaOH) and 93.5 kg / hr of water at 35 ° C. in the presence of 0.017 kg / hr of hydrosulfite , An aqueous phase cooled to 25 ° C. and an organic phase of methylene chloride 61.9 kg / hour cooled to 5 ° C. are supplied to a Teflon pipe having an inner diameter of 6 mm and an outer diameter of 8 mm, respectively. In a 34 m Teflon pipe reactor, it was contacted with 7.2 kg / h of liquefied phosgene having a chlorine content shown in Table 1 and separately cooled and cooled to 0 ° C.
The above-mentioned raw material (bisphenol A / sodium hydroxide solution) was subjected to phosgenation and oligomerization while flowing phosgene and the inside of the pipe reactor at a linear velocity of 1.7 m / sec for 20 seconds. At this time, the reaction temperature reached a top temperature of 60 ° C. in the adiabatic system. The temperature of the reaction was controlled by external cooling to 35 ° C. before entering the next oligomerization bath. In the oligomerization, 0.005 kg / hr of triethylamine was used as a catalyst, and 0.39 kg / hr of pt-butylphenol was used as a molecular weight regulator, each of which was introduced into the oligomerization tank.
[0023]
The oligomerized emulsion obtained from the pipe reactor in this manner is further introduced into a reaction tank having an internal volume of 50 liters equipped with a stirrer, and nitrogen gas (N₂) The mixture was stirred at 30 ° C under an atmosphere to oligomerize, so that the unreacted sodium salt of bisphenol A (BPA-Na) present in the aqueous phase was completely consumed, and then the aqueous phase and the oil phase were allowed to stand. Separation gave an oligomer in methylene chloride.
[0024]
23 kg of the above methylene chloride solution of the oligomer was charged into a 70-liter reactor equipped with a Faudler blade, 10 kg of methylene chloride for dilution was added thereto, and 2.2 kg of a 25% by weight aqueous sodium hydroxide solution and 6 kg of water were further added. And 2.2 g of triethylamine, and the mixture was stirred at 30 ° C. under a nitrogen gas atmosphere, and a polycondensation reaction was performed for 60 minutes to obtain a polycarbonate resin.
[0025]
30 kg of methylene chloride and 7 kg of water were added to the reaction solution, and the mixture was stirred for 20 minutes. Then, the stirring was stopped, and the aqueous phase and the organic phase were separated. To the separated organic phase, 20 kg of 0.1N hydrochloric acid was added, and the mixture was stirred for 15 minutes. After extracting triethylamine and a small amount of remaining alkaline component, the stirring was stopped, and the aqueous phase and the organic phase were separated. Further, 20 kg of pure water was added to the separated organic phase, and after stirring for 15 minutes, the stirring was stopped, and the aqueous phase and the organic phase were separated. This operation was repeated until no chlorine ions in the extraction wastewater were detected (three times).
The obtained purified polycarbonate solution was powdered by feeding it into hot water at 40 ° C., and dried to obtain a granular powder (flake). The nitrogen content in the flake was 1.5 ppm.
[0026]
For the measurement of the chlorine content in phosgene, 70 g of phosgene was collected, vaporized, absorbed in a NaOH solution, titrated as redox titration as NaClO, and the absolute amount was measured to determine the chlorine content in phosgene.
The average molecular weight of the oligomer, the average molecular weight and the molecular weight distribution of the flake, and the color tone of the molded product obtained in each example were measured. Table 1 shows the results.
Example 6
As a separately introduced liquefied phosgene cooled to 0 ° C., a 55 mmφ * 500 mm L cylindrical container is filled with activated carbon (manufactured by Ohira Chemical Co., Ltd., trade name: Yashikoru M) and passed through at -5 ° C. and 7.2 kg / hr. The procedure was the same as in Example 1, except that phosgene was used. Table 1 shows the results.
Particle size: Pass through 8 mesh sieve ~ 30 mesh sieve residue
Vacuum degree: 2.0 to 2.2 g / cc
Porosity: 33-45%
Specific surface area: 700-1500m²/ G
Average pore size: 12 to 40 angstroms
[0027]
[III] Physical property evaluation
The physical properties of the polycarbonate resins in Table 1 were evaluated as follows.
(1) Molecular weight distribution (Mw / Mn):
Using a GPC (Gel Permeation Chromatography) device (manufactured by Toso Corporation, product name: HLC-8020), and using tetrahydrofuran (THF) as an eluent, four kinds of high-speed GPC packing materials (Toso Corporation) ), Product name: TSK 5000HLX, 4000HLX, 3000HLX, and 2000HLX), and Mw and Mn were determined in terms of polystyrene from the chart obtained by detecting the difference in refractive index and obtaining Mw / Mn. Mn was calculated.
[0028]
(2) Color tone (YI):
[Formation of sample plate]
The flakes were plasticized at 280 ° C using an injection molding machine (manufactured by Nissei Resin Industry Co., Ltd., product name: FS80S-12ASE), and then retained in a cylinder for 15 seconds to obtain a 3.2 mm thick, 60 mm square sample. A plate was formed. Also, after plasticization, a sample plate having a residence time in the cylinder of 5 minutes was formed.
[Measurement of color tone]
The color tone (YI value) of these sample plates was measured using a color difference meter (manufactured by Suga Test Instruments Co., Ltd., product name: SM-4-CH). Among the measured values, a small YI value at 15 seconds retention indicates that the color tone during steady molding is good, and a small difference (ΔYI) between the 15 seconds and 5 minutes retention YI values indicates a high temperature. Shows that the thermal stability is good.
[0029]
(3) Measurement of the amount of volatile chlorine:
After heating at 280 ° C. for 30 minutes by the following method, evaluation was made by measuring the amount of chlorine generated by heating when the sample was kept at room temperature for 3 days.
The flakes were kneaded at a resin temperature of 290 ° C. in a 30 mm twin screw extruder (made by Ikegai Iron and Steel), and then pelletized. At this time, there is a concern that chlorine may be mixed in the operation (Human hands, sweat, and H used for cooling).₂Regarding 0), we paid close attention to processing.
10 g of the obtained pellets were charged into a glass tube having an inner diameter of 10 mm, which had been washed with ion chromatography water, and sealed under vacuum (the length of the sealed tube was constant at 20 cm). The whole glass tube was kept standing in an oil bath at 280 ° C. for 30 minutes, cooled, washed thoroughly with oil and the like adhering to the outside, and then kept at room temperature for 3 days while keeping the glass tube as it was.
The portion immediately above the infiltrated portion of the polymer was cut (fired) and the inside of the upper glass was washed with 1 ml of pure water, collected, analyzed by ion chromatography, and determined as the amount of chlorine generated by heating per 1 g of the polymer.
[0030]
[Table 1]

[0031]
Comparative Examples 1-3
In Example 1, the same operation as in Example 1 was carried out except that the liquefied phosgene whose chlorine content in phosgene was adjusted to the concentration shown in Table 2 was used, and that the phosgene was not passed through the activated carbon tower. went.
[0032]
[Table 2]

[0033]
【The invention's effect】
The polycarbonate resin having a small amount of volatile chlorine of the present invention has a small amount of chlorine which gradually evaporates when held at room temperature and has a stable quality.
In addition, the polycarbonate resin obtained by the production method of the present invention has, in addition to the above properties, significantly improved thermal stability in high-temperature molding, a small change in hue after melt molding, and a molded article with less coloring can be obtained. Since it can be used, it has an advantage that its application range can be greatly expanded as compared with conventional products.

Claims (16)

A polycarbonate resin having a small amount of volatile chlorine, wherein the amount of chlorine generated by heating when heated at 280 ° C. for 30 minutes and kept at room temperature for 3 days is 30 ppb or less. The polycarbonate resin having a small amount of volatile chlorine according to claim 1, wherein the amount of chlorine generated by heating is 20 ppb or less. The polycarbonate resin having a small amount of volatile chlorine according to claim 1 or 2, wherein the amount of chlorine generated by heating is 1 to 20 ppb. The polycarbonate resin having a small amount of volatile chlorine according to any one of claims 1 to 3, wherein the polycarbonate resin has a viscosity average molecular weight Mv of 10,000 to 100,000. In the production method of the resin having a carbonate bond using phosgene as a raw material, the chlorine concentration is characterized Rukoto using the following 1,000ppb as e Sugen, method of manufacturing small polycarbonate resin volatile chlorine. A method for producing a resin having a carbonate bond using phosgene as a raw material, wherein a polycarbonate resin having a chlorine concentration of 1,000 ppb or less obtained by treating with an adsorbent as phosgene is used. Manufacturing method. A method for producing a resin having a carbonate bond using phosgene as a raw material, characterized in that a chlorine concentration of 1,000 ppb or less obtained by treatment with activated carbon is used as phosgene, wherein the polycarbonate having a low volatile chlorine content is used. Method of manufacturing resin. The method for producing a polycarbonate resin having a low content of volatile chlorine according to any one of claims 5 to 7, wherein a phosgene having a chlorine concentration of 500 ppb or less is used . The method for producing a resin having a carbonate bond using phosgene as a raw material is a method for producing a polycarbonate resin by reacting phosgene or a carbonate raw material using phosgene with a diphenol . 3. The method for producing a polycarbonate resin having a small amount of volatile chlorine as described in 1. above. The method for producing a polycarbonate resin having a small amount of volatile chlorine according to claim 9 , comprising a step of reacting a diphenol and phosgene in the presence of water and an organic solvent. The method for producing a polycarbonate resin having a small amount of volatile chlorine according to claim 9 or 10 , wherein at least a part of the diphenols is reacted with phosgene as an alkali metal salt. The volatilization according to claim 10 or 11 , comprising a step of reacting a diphenol with phosgene in the presence of water and an organic solvent, and a step of subjecting the polycarbonate oligomer obtained in the step to a polycondensation reaction to obtain a polycarbonate. Method for producing polycarbonate resin with low chlorine content. The method for producing a polycarbonate resin having a low volatile chlorine according to any one of claims 9 to 12, wherein a diaryl carbonate obtained by reacting phosgene with a monohydroxy aromatic compound is used as a carbonate raw material. The method for producing a polycarbonate resin having a low volatile chlorine according to any one of claims 5 to 13 , wherein phosgene obtained by a reaction between carbon monoxide and chlorine is used as phosgene. By reacting phosgene, whose chlorine concentration has been reduced to 1,000 ppb or less by adsorption treatment with activated carbon in a liquid state, with diphenols which are at least partially alkali metal salts in the presence of water and an organic solvent. A method for producing a polycarbonate resin having a small amount of volatile chlorine, comprising producing a polycarbonate oligomer and then subjecting it to polycondensation. The method for producing a polycarbonate resin having a low volatile chlorine according to claim 15, wherein phosgene whose chlorine concentration is reduced to 500 ppb or less is used.