JPS5819328A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To obtain a polycarbonate which can be readily purified and has less thermal discoloration, by phosgenating a dihydric phenol in the presence of an organic solvent, then bringing the reaction medium to an emulsion state and effecting the polymerization reaction while adding a dihydric phenol. CONSTITUTION:A low-MW polycarbonate is formed by reacting phosgene with an aqueous alkali solution of a dihydric phenol such as bisphenol A in the presence of an organic solvent (e.g., methylene chloride, trichloroethane). Then, by means of a homogenizer, a mixer or the like, the reaction medium is brought to an emulsion state, and the low-MW polycarbonate is polymerized while a dihydric phenol in an amount providing a mol ratio to the dihydric phenol charged before the phosgenation reaction of 0.002-0.1 is being added in small portions. After the reaction, the formed mixture is separated into a water phase and an organic phase, and the organic solvent in the latter phase is removed to obtain the purpose polycarbonate.

Description

[Detailed description of the invention]

The present invention relates to a method for producing polycarbonate, and more particularly to a method for producing polycarbonate F, which allows purification of a polybenz solution after the reaction is completed, and which exhibits less discoloration due to heat. Conventionally, as a manufacturing method of polycarbonate,! A low molecular weight polycarbonate is formed by reacting an aqueous solution of phenol with phosgene in the presence of an organic solvent, and the reaction medium is then formed and maintained in an emulsified state to form a predetermined polymer shelf). , fffiKI! *The aqueous solution that gave rise to the rumor of harsh soda is stably dispersed in the form of small droplets, and it is extremely difficult to remove them by washing with water. There are drawbacks that make it difficult. Furthermore, even if the polyw-solution produced by this method is sufficiently purified, the purified polymer will change color if kept in air at a relatively high temperature, e.g. Therefore, there is a need for manufacturing SMVC in fields where it is used at high temperatures.As a result of intensive research to improve these drawbacks, the present inventors were able to maintain an emulsified state and obtain a polycarbonate with a desired high molecular weight. The present invention was achieved by discovering that by adding 2@phenol during the reaction, it is possible to obtain a polycarbonate that can be easily purified and has less thermal discoloration. Rumor has it that a polycarbonate is manufactured by reacting with phosgene in the presence of an organic solvent to form a low molecular weight polycarbonate and then forming a high molecular weight polycarbonate in a medium which is maintained in an emulsified state. Method-1
It's even more of a struggle to maintain the emulsified state! This is a method for preparing polycarbonate, which is characterized by adding a functional phenol. The rich phenol used in the present invention is 44゛-dioxydiphenyl-kame! - dioxydiphenylfurcanes, including dioxydiphenylfurcanes (hereinafter referred to as bisphenol A), dioxydiphenyl citaloalkanes, dioxydiphenyl ether*, dioxydiphenyls,
9. Oxydiphenyl sulfones, dioxydiphenyl sulfides, dioxydiphenyl sulfoxides, dioxydiphenyl carboxyls. Dioxydiphenylcarbosils and these ^-
or a furkyl substituted derivative, or a mixture thereof. In addition, a small amount of dihydric phenol in the initial charge was added to
It can also be used in place of polyfunctional compounds such as 2mglucine, λ4-dihydro1xbenzoic acid, and diphenolic acid. These dihydric phenols are dispersed in the 74-power liquid water.

[Used conveniently. In this case, as the alkali, an alkali metal hydroxide such as caustic soda or hydroxide is preferably used, and the concentration in the aqueous solution is usually 7 to 11% by weight. #1 Solution Disperse 2 Nod The molar ratio of phenol and alkali is 1:t! Preferably 1% to 11. In order to prevent oxidative coloration of dihydric phenol, a selective agent such as bilayer sulfuric acid, Heid ρ sulfide, etc. may be added as an oxidative antifat agent. Furthermore, in order to facilitate the phosgenation reaction and the heavy-duty reaction, Yuki #*Sake is used. The organic #1 medium used is an organic compound that is substantially insoluble in water and inert to the reaction, yet dissolves the polycarbonate present in the reaction. Methylene coolide, tetracoolethane. Salt volumized aliphatic hydrocarbons such as L2-citrate ethylene, p-form, 1st carbon chloride, tricoolethane, ditarethane; p-benzene, dipvz4 benzene,
Examples include chlorinated aromatic hydrocarbons such as cool toluene; 7cetophenone, cyclohexane, anisole, etc. alone or in mixtures. Among these, methylene coolide is the most preferred and common. In the present invention, first, phosgene is introduced while stirring dihydric phenol-based liquid phenol and an organic solvent. The phosgene to be introduced may be in either a liquid state or an organic hot medium solution. The amount thereof is usually in a molar ratio of LO5 to tS@ degrees with respect to all dihydric phenols including dihydric phenols added later. For the purpose of controlling the molecular weight of the polycarbonate produced,
Molecular weight regulators are generally used. Examples of this molecular weight regulator include phenol. Examples include monohydric phenols such as p-cresol and p-tert-butylphenol; 11i alcohols such as methanol, ethanol, and Schiff-hexanol. be. The amount added varies depending on the target molecular weight, but the molar ratio to the total dihydric phenol is usually 601 to 1.
It is a2s degree. The phosgenation reaction by introducing phosgene can be carried out under conventionally well-known conditions.
When carried out under the conditions described in Bscho-219s Publication, "can be obtained." In the present invention, a low molecular weight polycarbonate is formed by a phosgenation reaction, and then the reaction medium is brought into an emulsified state KL, and this emulsified state is The low molecular weight polycarbonate F is polymerized while maintaining the high molecular weight polycarbonate) K.
do. At this time, various conditions must be met in order to obtain a good emulsified state. There is a ratio of the aqueous phase to the organic phase in the L reaction mixture. This ratio is usually a volume ratio of 1. For OK

[Organic phase a4 to 169 degrees. Another important condition is the ratio of the organic solvent to the polycarbonate, and a preferable concentration of the polycarbonate (+) is 8 to 30% by weight. [Methods for emulsifying the reactive ia* liquid include a method of adding alkaline water elutriation while stirring, and a method of varying the stirring speed. A simple stirrer (Bubera,
It is also possible to emulsify by increasing the rotational speed using a turbine, pot-blade, chisel, etc.
There is a limit to one degree of emulsification. The equipment used to obtain an emulsified state of 1 degree El is homogenizers, mixers, high-speed stirrers such as homomixers, orifice mixers, static mixers, colloid mills, 7-diene) 4 xer-0 ultrasonic emulsification equipment, etc. are suitable, and when these are used, a highly emulsified layer with a more thorough droplet size can be obtained than the droplet-equivalent emulsified layer obtained with a simple stirrer. is the emulsified state by the above-mentioned simple stirrer, one-time emulsified state S, or
You can use any combination of them as appropriate. Further, as the polymerization conditions, conventionally known conditions can be used. In the conventionally known method, the polymerization reaction is proceeded as it is under the sieve in the obtained emulsified state; however, in the method of the present invention, this emulsified state is maintained and further dihydric phenol is added to the sieve. is added to advance the polymerization reaction. By doing so, it is possible to purify the polycarbonate solution after the reaction is completed and to obtain a polycarbonate with little thermal discoloration. The key to this emulsified state is the amount of dihydric phenol added to the amount of dihydric phenol charged in 11 for phosgenation, and the ratio is (LO6!-01@ degrees.This is the fI form as it is. You can also add -1 to 7 by dissolving organic solvent Km such as water happy liquid or methylene tacylide and concentrating!!13
It is preferable to add it as a ~20 wt. solution. This dihydric phenol is preferably added in small amounts continuously or intermittently over time during the period when the reaction mixture becomes milk-like and the polycarbonate grows from a low molecular weight to a high molecular weight. If the addition time is too late, it will not be possible to maintain an emulsified layer, and if the addition is completed too early, the effects of purification of the 1ff-solution after the reaction and discoloration of the product will be poor. Both will no longer be expressed. I'll obey! Addition of Confucian phenol, Honugunyi-
After reaction, it forms an emulsified layer and starts the polymerization reaction.
It is most desirable to add the mixture and then allow it to finish for 30 to 10 minutes, during which time the rate of addition is varied.
A sufficient effect can be obtained by continuously adding a small amount at a constant speed and intermittently. 2@After addition of phenol Descendant 1. Stirring is continued to form an emulsified layer, the final viscosity is reached, and the reaction is terminated at point t.The aqueous phase of the resulting mixed solution after the completion of the reaction contains a hydrated alkali metal. Since by-products such as carbon salt and chloride are included, it is necessary to remove them. For this purpose, the resulting mixed solution is diluted as it is or by dilution, and if necessary, a demulsifier is added or passed through a hydrophilic material to separate the aqueous and organic phases. Separate and further*
The product sum is thoroughly washed with water until by-product tJt is no longer detected. The number of washing times IB required by the conventional method is about 1/! is sufficient. It is possible to remove the organic solvent from the washed organic phase to obtain a solid high molecular weight polycarbonate. Polycarbonate 11 obtained by the present invention
06-! It has an average molecular weight of 0 (LOO4), and its molded products have excellent transparency, mechanical strength, electrical strength, etc. unique to polycarbonate. In addition, this polycarbonate material has a remarkable improvement in thermal discoloration that occurs when kept in a high-temperature air atmosphere for a long period of time, so it has the advantage of greatly expanding its range of applications compared to conventional products. Hereinafter, the present invention will be further explained with reference to examples, but the present invention does not go beyond these examples and is not limited to these examples. Comparative Example 1 Bisphenol A in a 201 reactor with an anchor
IL! Ill to 1 (l giNaOH aqueous solution 1tB
klIK happy, then methylene chloride 11fu 81
Hosuge 7111 @ 1 injection and stirring at 21 Or- rotation speed
Multiply 5o9I to find the reaction temperature! After blowing under conditions of s±1°C to produce a low molecular weight polycarbonate, tert-tertiarybutylphenol 41j is added as a molecular weight regulator.
J was dissolved in "*Naox aqueous solution @O・IK" and added. From this K!L reaction solution formed an emulsified state with the organic phase as the delivery phase and the aqueous phase as the dispersed phase. Stir in this emulsified state. The reaction was continued for 4 hours at a temperature of lo±1°C. At this point, reaction #11 had reached its final viscosity. Purification was then carried out. Namely, methylene chloride 116j was added to this product mixture. In addition, the diluted fireflies were separated into an organic phase and an aqueous phase using F paper (Toyo F paper Na!?).The organic phase was extremely cloudy, and a large amount of the aqueous phase still remained as fine particles. When I measured the moisture content, it was 42 degrees.Next, I washed it with water for the first time.That is, I took out the * phase, added 10J of pure water, mixed it thoroughly with K11, filtered it with F paper, and washed it with water for the first time. Furthermore, water washing was repeated in the same manner. Chlorine ions in the water washing wastewater were detected by silver nitrate, and it took a total of 6 water expansions until they disappeared. The average molecular weight of the obtained polycarbonate was measured and was 60. Then methylene coolide 1787
was added, and 1 kl of phosgene was added to the reaction temperature for 110 minutes under stirring at a rotation speed of t 1 o rpm. The mixture was blown under conditions of s±1°C to produce a low molecular weight polycarbonate. Next, p-tert-butylphenol 41L as a molecular weight moderation agent! I was happy to add 19t #21JN Maro OH water #1 liquid 6/OI. This K formed the reaction solution St in an emulsified state. So bis7e/-kAfJharukamjll(
Addition of the aqueous KaOH solution of Bis7z/-Am was started and was added systematically over 120 minutes. The amount of additional bisphenol A added was 4L @lI, and the additional solution was added to the bisphenol uneven Na0B aqueous solution, and the amount of bisphenol A measured: 8 @I/I
e) imOHill *: 1 1
j' / j [1 m1 subtracted. After that, ff1l is maintained at SO ± 1°C while maintaining the emulsified state.
Turn off stirring. At this point the reaction solution had reached its final viscosity. Next, purification was performed in the same manner as in Comparative Example 1. After diluting the heated mixture by adding methylallide, it was filtered through F paper and separated into an organic phase and an aqueous phase. The organic @ II was highly transparent with less turbidity, and when the moisture content was measured (Lllll+), it took three washings until no chlorine ions were detected in the washing wastewater. From this, 1 Example 1 of the present invention has a significantly higher N value than Comparative Example IK.
It turns out that # is easy. In addition, the average molecular weight of the polycarbonate was measured after the solvent in the organic phase was evaporated after purification! It was @1000. Comparative Example 2 ttolf with amm material) 1L reaction vessel [Bisphenol Atzsky] % NaOH water solution 1alkl
Dissolve in, then methylene chloride 1! Input $4, rotation speed 2) Phosdane Ll under stirring of Otp-! kl
Spend 90 minutes [! ! CP-Tasha Sobutylphenol-441!j was used as a zero-order molecular weight modifier made from a low-molecular-weight substituted carbonate by blowing at a temperature of 26±1°C.
After adding NaOH water to the me @ JIKm, gL
Using a type homo I mixer (Tokushu Kika Kogyo ■1), the rotation speed -
The mixture was stirred for 2 minutes at o o @ rp- to form a highly emulsified mass. Next, the mixture was stirred again using a circular deaf blade, and the reaction was carried out at a temperature of 30±1° C. for 2 hours. At this point the reaction was at a suitable final viscosity. Next, purification was performed in the same manner as in Comparative Example 1. The resulting mixture was diluted with methylene chloride, and then filtered through paper to separate it into an organic phase and an aqueous phase. The obtained organic phase has a remarkable moisture content, and its moisture content is 62-
Met. It took six flushes until the chlorine ions in the flushing wastewater disappeared. The average molecular weight of the polycarbonate was 1 snow nine.O. Example! 2.4 reactors with end-heavy blades
1!3- to 1・-NaOII aqueous solution 1 turtle 7#Kt/I
I, then add methylene chloride & 7jl.
Phosgene Ll Ikl under stirring at rotational speed 210 rpas
was blown for 10 minutes at a reaction temperature of 2S±1°C to produce polycarbonate F with a potted molecular weight.
% Na0I (aqueous solution 606NK was dissolved and added, and then the rotation number was 8000 rp-
The mixture was stirred for 2 minutes to form a highly emulsified state. Next, the additional solution of bisphenol A (
Addition of bisphenol A (Na0F, solution) was started and was continuously added over 60 minutes. Amount of added bisphenol A: 4! L6.9, additional liquid is Example 1
It has the same composition as . Thereafter, stirring was carried out at 3·±1°C for 1 hour. At this point the reaction had reached its final viscosity. Next, purification was performed in the same manner as in Comparative Example 1. After diluting the resulting mixture by adding methylenetalolide, it was filtered through two pieces of paper and separated into an organic phase and an ice phase. The resulting organic phase had less turbidity and a greater degree of transparency, and its moisture content was measured to be 16. It required washing with water until the chlorine ions in the washing wastewater disappeared. From this, Example 2 of the present invention is a comparative example! Compared to
It turns out that refining is the container. In addition, when we measured the average molecular weight of polycarbonate,
Example 4 The purified polycarbonate solutions obtained in Comparative Example 1.2 and Example L2 were granulated using a kneader, dried, pelletized in an extrusion manner, and s molded using an injection molding machine. A sample board with a thickness of 2W was molded at !0°C. This sample board was placed in a heat dryer and heat treated at 1116°C for 20 days. The hue of the sample board after 5yit of heat treatment (b
Values) were measured using a color difference needle (Suga Test Instruments KL11) to obtain the results for summer. Table 1: A large hue (b value) bll of a sample plate after heat treatment indicates a large yellowing coloration. From the results of 41-I, it can be seen that the product according to the present invention has a color change during heat treatment of less than f\rt and improved heat resistance.

Claims (1)

[Claims] L. Alkaline water of phenol m* and phosgene are reacted in the presence of an organic solvent to form a low molecular weight bocarbonate, and then in a reaction medium containing emulsified 11KII. A method for producing d/III carbonate comprising forming a high molecular weight polycarbonate (1)
While maintaining the emulsified state! To 2! @A polycarbonate preparation machine characterized by the addition of phenol. 1 The amount of 2Il phenol added is 410% compared to the amount of dihydric phenol charged in phosgenation.
@! 〜(Ll) The manufacturing method according to item 1 of the patent-requested *m.