JPH0471412B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for solidifying polycarbonate resin, and specifically, a method for producing an aqueous slurry in which polycarbonate resin is dispersed as bead-shaped solidified particles by using a wet pulverization method. The aqueous slurry liquid has little contamination of fine "dust" due to slurry transfer during the manufacturing process, and can be easily filtered and dried, and is particularly suitable for manufacturing optical polycarbonate resins. It is suitable as [Prior art and its problems] Conventionally, the method of extracting dry solid powder used for manufacturing pellets from a polycarbonate resin solution usually involves producing a semi-crystalline or amorphous solidified material solidified in a solidification tank. It depends on the method of separating by filtration, crushing, and then drying. This method is preferable from the viewpoint of the size of the manufacturing equipment and processing efficiency, but during the process of transferring the water slurry liquid of the solidified product to the process of pulverizing the solidified product, "garbage" is generated and mixed in from piping and equipment. Due to these problems, it has sometimes been insufficient as a method for producing polycarbonate resins for applications that require higher quality, that is, less "dust", particularly for optical applications. [Means for Solving the Problems] As a result of intensive study by the present inventors on a method that substantially eliminates the generation of "garbage" due to transportation in piping and pulverization of solidified materials, the present inventors found that wet pulverization is performed at the same time as solidification. They discovered a method and completed the present invention. That is, the present invention involves adding and mixing a purified solidifying solvent to a purified polycarbonate resin solution, and distilling off the solvent and solidifying solvent while adding the mixed solution to hot water under heating. A method for producing a water slurry of solidified polycarbonate resin, which is characterized in that the liquid in the solidification process is solidified while being circulated to a wet grinder, and is preferred. In an embodiment, solidifying at a temperature of 45° C. to 100° C. using a solidifying solvent 0.1 to 0.5 times the volume of the polycarbonate resin solution;
By circulating the liquid during the solidification process to the wet grinder at a rate of 1 to 30 times the total solidification liquid per hour, 90% by weight or more of the solid content after drying is bead-shaped polycarbonate solid particles, and The average diameter of the beads is
0.5 to 2 mm and bulk specific gravity of 0.3 to 0.6 g/cc, and the viscosity average molecular weight of the polycarbonate resin of the purified polycarbonate resin solution used for this is in the range of 13,000 to 20,000, and the concentration is 10% to 25% by weight is used. The configuration of the present invention will be explained below. The polycarbonate resin solution of the present invention is produced by a method similar to that of conventional polycarbonate resins, that is, by an interfacial polymerization method, and contains a dihydric phenol compound (hereinafter abbreviated as BP) as the main component, with a small amount of molecular weight control. A solution of a homo- or copolymer of an aromatic polycarbonate resin made by reacting with phosgene using an agent and optionally a branching agent. Preferred as the BP of the present invention are compounds represented by the following general formula (1), General formula (1): (R in the formula is a divalent aliphatic, alicyclic, or phenyl-substituted alkyl group having 1 to 15 carbon atoms, or
-O-, -S-, -SO-, _-SO2- , -CO-. X is an alkyl group, an aryl group, or a halogen atom, and p and q are integers of 0 to 2. ) Specifically, bis(4-hydroxyphenyl)
Methane, bis(4-hydroxyphenyl) ether, bis(4-hydroxyphenyl) sulfone,
bis(4-hydroxyphenyl) sulfoxide,
Bis(4-hydroxyphenyl) sulfide, bis(4-hydroxyphenyl)ketone, 1,1-
Bis(4-hydroxyphenyl)ethane, 2,2
-Bis(4-hydroxyphenyl)propane (hereinafter referred to as bisphenol A), 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane (hereinafter referred to as bisphenol A), phenol Z), 2,2-bis(4-hydroxy-3,5-dibromophenyl)
Propane, 2,2-bis(4-hydroxy-3,
5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane, 2,2-bis(4-hydroxy- 3,5-dimethylphenyl)propane,
Examples include 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, and bis(4-hydroxyphenyl)diphenylmethane. Branching agents include phloroglycin, 2,6-
Dimethyl-2,4,6-tri(4-hydroxyphenyl)heptene-3, 4,6-dimethyl-2,
4,6-tri(4-hydroxyphenyl)heptene-2, 1,3,5-tri(2-hydroxyphenyl)benzole, 1,1,1-tri(4-hydroxyphenyl)ethane, 2, Examples include 6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, α,α′,α″-tri(4-hydroxyphenyl)-1,3,5-triisopropylbenzene, etc. Polyhydroxy compound, and 3,3-bis(4-hydroxyaryl)oxindole (=isatin bisphenol), 5-
A branching agent, exemplified by chloroisatin bisphenol, 5,7-dichloroisatin bisphenol, 5-bromyisatin bisphenol, etc., is added to the divalent phenolic compound of general formula (1) above,
Usually 0.02 to 3 mol%, preferably 0.1 to 1.0 mol%
Use the range of In addition, monovalent aromatic hydroxy compounds are used as molecular weight regulators or terminal stoppers, such as m- and p-methylphenol, m- and p-propylphenol, p-bromophenol, p-
Preferred are tert-butylphenol and p-long chain alkyl substituted phenols, P-long chain alkyl etherified phenols, P-hydroxyalkyl benzoates, and the like. In particular, aromatic polycarbonate resins include:
Examples include polycarbonates containing bisphenol A as a main raw material, polycarbonate copolymers obtained by combining bisphenol Z, etc., branched products thereof, and those modified with long-chain alkyl terminals. Examples of the solvent used in the reaction include chlorinated aliphatic or aromatic hydrocarbons such as methylene chloride, 1,1-dichloroethane, chlorobenzene and chlorotoluene, with methylene chloride being particularly preferred. The polycarbonate resin solution produced by the above method is subjected to conventional methods such as removal of the catalyst, neutralization, washing with water, concentration, etc., and further microfiltration to obtain the purified polycarbonate resin solution of the present invention. Here, the amount of fine "dust" in the purified polycarbonate resin solution is preferably as small as possible, but for example, if the particle diameter is 0.5μ
It is best to limit the number of "garbage" of 1 m or more to 1000 pieces or less in 1 c.c., and the concentration should be in the range of 10 to 25% by weight, especially
It is preferably 10 to 20% by weight. In this purified polycarbonate resin solution,
Usually, a solidifying solvent is added and mixed at room temperature, and then the mixed solution is added to hot water under heating while the solvent and solidifying solvent are distilled off, and the solidifying liquid is circulated to a wet grinder. and crush. As the solidifying solvent, use 0.1 to 0.5 times the volume of the polycarbonate resin solution, preferably 0.2 to 0.4 times the volume, at a temperature of 45°C to 100°C, preferably 45°C to
Solidify at 60℃. The amount of solidification solvent added and the addition temperature are such that the solution after addition of the solidification solvent becomes a gel when left standing at the same temperature or forms a precipitate when the temperature is lowered. In the present invention, solidification is performed by simultaneously distilling a mixed solvent of a polycarbonate resin solvent and a solidifying solvent from a mixed solution. In the case of a polycarbonate resin solution containing only a solvent, the polycarbonate resin and solvent are completely compatible even after the solvent is distilled off, so the concentration of the polycarbonate resin simply increases, resulting in solidification. Conceivable. However, in the case of the mixed solvent of the present invention, since the polycarbonate resin and the mixed solvent are not completely miscible, the precipitate cannot be formed at a high concentration that would not normally be thought of as the mixed solvent decreases with respect to the polycarbonate resin. It is presumed that the mixed solvent will be distilled off while forming a precipitate. In the present invention, while adding the solution after addition of the solidifying solvent into hot water under heating, the solvent and the solidifying solvent are added for usually 0.1 to 1.0 hours, preferably 0.5 to 1.0 hours.
1 to 30% of the total solidified liquid is added so as to be distilled off in 1.0 hour, and the liquid in the solidification process is sent to a wet grinder.
Wet grinding is carried out by circulating at a rate of 5 times/hour, preferably 5 to 20 times/hour. Here, the wet grinder may be a commercially available one, and preferred examples include Golatol (trade name) manufactured by Aikawa Tekko Co., Ltd. and Dice Integrator (trade name) manufactured by Komatsu Zenoah Co., Ltd. The bead-shaped polycarbonate solid particle aqueous slurry of the present invention can be obtained by the above method. The polycarbonate solid particles in this aqueous slurry have bead-shaped polycarbonate solid particles that account for 90% or more of the solid content after drying, and the beads have an average diameter of 0.5 to 2 mm and a bulk specific gravity of 0.3 to 0.6 g/cc.
This product has low resistance due to transfer through piping in the state of water slurry, can be efficiently separated and dried in the post-processing process, and has a good shape even as a dry powder. Since it is bead-shaped, the generation and contamination of "dust" due to contact with piping and equipment walls is also reduced. [Example] Hereinafter, the present invention will be specifically explained using examples. Example 1 Dissolve 117 kg of sodium hydroxide in 1320 kg of water,
2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as BPA) 250°C while keeping at 20℃
Kg, 2,6-dimethyl-2,4,6-tri(4-
Hydroxyphenyl)heptene-3 0.883Kg,
Hydrosulfite 0.860Kg was dissolved. To this was added 960 methylene chloride, and while stirring, 128 kg of phosgene was blown in over 35 minutes. After blowing phosgene, 12.3 kg of p-tert-butylphenol (hereinafter referred to as PTBP) methylene chloride solution was added and vigorously stirred to emulsify the reaction solution. After emulsification, 0.2 of triethylamine and 300 of methylene chloride were added to approx. Stirring was continued for hours to allow polymerization. The polymerization solution was separated into an aqueous phase and an organic phase, and the organic phase was neutralized with phosphoric acid, and then water washing was repeated until the pH of the washing solution became neutral to obtain a purified polycarbonate resin solution. This purified solution was microfiltered using a cartridge filter with a filtration accuracy of 0.2 μm. To this filtered and purified solution, n-hexane, which had been microfiltered using a cartridge filter with a filtration accuracy of 0.2 μm, was added at room temperature while stirring at 380 °C.Then, this mixed solution was added to warm water under heating and stirring while the solvent was removed. While methylene chloride and n-hexane, the solidification solvent, are distilled off, this liquid is circulated at a rate of 40 m ³ /hour to a wet grinder (Golatoll: trade name) for wet grinding, resulting in a concentration of bead-shaped polycarbonate resin solids. A 10% by weight water slurry was obtained. Solidification time was about 1 hour. The solid content was separated from this water slurry in a clean room and dried in a drier that circulated clean air. The measurement results of this solidified material are shown in Table 1. Examples 2 to 4 In Example-1, 22.4 kg of lauryl p-oxybenzoate and 2,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)heptene-3 were used instead of PTBP. α, α′, α″−tri(4
-Hydroxyphenyl)-1,3,5-triisopropylbenzene 1.05Kg (Example 2), in Example 1, p
-dodecyloxyphenol 20.4Kg (Example 3) and Example 1, p-stearylphenol 24.3Kg instead of PTBP,
α, α′, in place of 2,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)heptene-3
α″-tri(4-hydroxyphenyl)-1,3,
The procedure was the same except that 1.05 kg of 5-triisopropylbenzene was used (Example 4). The measurement results are shown in Table 1. Comparative Example 1 In Example 1, instead of solidifying the liquid during the solidification process while circulating it in a wet pulverizer, the liquid was solidified without circulating in the wet pulverizer during the solidification process, and the resulting average diameter was approximately The procedure was the same except that the water slurry of the 5 mm solidified material was circulated to a wet pulverizer and pulverized. The results are shown in Table 1. Comparative Example 2 The same procedure as in Example 1 was carried out except that n-hexane was not used. The results are shown in Table 1. Example 5 In Example 1, n-hexane was replaced with n
- Same procedure except that heptane 400 was used. The results are shown in Table 1. Example 6 The procedure of Example 1 was repeated except that cyclohexane 500 was used instead of n-hexane. The results are shown in Table 1.

[Table]
As is clear from the above detailed description and examples, the polycarbonate resin obtained by the solidification method of the present invention has very little contamination of "dust" from piping, equipment, etc., and is extremely clean, just like in a solution. I understand that.

Claims (1)

[Claims] 1. Adding and mixing a purified solidifying solvent to a purified polycarbonate resin solution, and distilling off the solvent and solidifying solvent while adding the mixture solution to hot water under heating. 1. A method for producing an aqueous slurry of bead-shaped polycarbonate solid particles, the method comprising: solidifying the solution while circulating it in a wet grinder during the solidification process. 2. The manufacturing method according to claim 1, wherein the solidification solvent is used in an amount of 0.1 to 0.5 times the volume of the polycarbonate resin solution and solidified at a temperature of 45°C to 100°C. 3. The manufacturing method according to claim 1, wherein the amount of the liquid during the solidification process that is circulated to the wet grinder is 1 to 30 times the total solidification liquid per hour. 4. Claim 1, wherein 90% by weight or more of the solidified polycarbonate resin after drying is bead-shaped polycarbonate solid particles, and the beads have an average diameter of 0.5 to 2 mm and a bulk specific gravity of 0.3 to 0.6 g/cc.
Manufacturing method described in section. 5 The viscosity average molecular weight of the polycarbonate resin in the purified polycarbonate resin solution is 13,000 ~
20000 and the concentration is 10% to 25% by weight
The manufacturing method according to claim 1.