JPH082968B2 - Method for producing powdery polycarbonate - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a powdery polycarbonate.

[0002]

2. Description of the Related Art There are a melt polycondensation method (transesterification method) and an interfacial polycondensation method (phosgene method) as a method for producing a polycarbonate. The interfacial polycondensation method is preferably used as an industrial method for producing a polycarbonate. Has been done.
In the method for producing a polycarbonate based on the interfacial polycondensation method, an emulsion solution obtained by the interfacial polycondensation reaction is washed and separated to first obtain an organic solvent solution of polycarbonate (the solvent is generally methylene chloride). Then, the polycarbonate is separated (collected) from the obtained organic solvent solution as powder or granules. After that, the obtained polycarbonate is molded into pellets or the like, if necessary.

As a simple method for recovering polycarbonate as a powder from an organic solvent solution of polycarbonate, an organic solvent solution of polycarbonate and steam are introduced into a jet nozzle (mixing nozzle), and a mixture jetted from the jet nozzle is passed through a pipe. Introduced into the separator,
A method for recovering powdery polycarbonate by this separator is known (Japanese Patent Publication No. 63-1333, Japanese Patent Publication No. 2-6561 and US Pat. No. 3,508,339). Then, when recovering the powdery polycarbonate by this method, the weight of the steam (W _S) and the ratio of the weight of the organic solvent in the organic solvent solution of the polycarbonate (W _O) to _{(W S / W O) 1} / 5, the steam and the organic solvent solution are introduced into the mixing nozzle. This method is a method of adding a poor solvent to an organic solvent solution of polycarbonate (Japanese Patent Publication No. 42-14474) or a crushing method by a kneader utilizing crystallization of an organic solvent solution of polycarbonate (Japanese Patent Publication No. 53-1589).
9) or a method in which an organic solvent solution of polycarbonate is added to warm water (Japanese Patent Application No. 60-115625) and the like, powdery polycarbonate having a small amount of residual solvent can be easily recovered. have.

[0004]

However, the bulk density of the polycarbonate obtained by the conventional method of introducing the organic solvent solution of polycarbonate and steam into the mixing nozzle and recovering the polycarbonate as powder from the mixture jetted from the jet nozzle is , As low as 0.05 to 0.35. For this reason, the volumetric efficiency of the processing equipment used for post-treatment such as drying or storage of the obtained powdery polycarbonate also becomes low, and large processing equipment is used as these processing equipment, or the volume of the processing equipment used is reduced. There was a drawback in that production adjustments had to be made accordingly.

Therefore, it is an object of the present invention to provide a method for producing a powdery polycarbonate which can easily obtain a powdery polycarbonate having a high bulk density and a small amount of residual solvent.

[0006]

The method for producing a powdery polycarbonate of the present invention which achieves the above object, comprises introducing a polycarbonate organic solvent solution and steam into a mixing nozzle, and separating the mixture injected from the mixing nozzle. Guided to a vessel
In the method for producing a powdery polycarbonate in which polycarbonate is charged and recovered as powder, an organic solvent solution having a polycarbonate concentration of 3 to 40% by weight is used as the organic solvent solution, and the weight of the steam at the time of introduction (W
The ratio (WS / WO) of S) to the weight (WO) of the organic solvent in the organic solvent solution is 1/10 to 1/5 .
And the pipe diameter (inner diameter D) of the pipe connecting the mixing nozzle and the separator
The ratio (L / D) of pipe length (L) to 100 to 10,000
It is characterized by

Hereinafter, the present invention will be described in detail. First, the organic solvent solution of polycarbonate used in the present invention (hereinafter sometimes simply referred to as an organic solvent solution) will be described. As described above, the concentration of the polycarbonate in the organic solvent solution is 3 to 40% by weight (hereinafter, referred to as% by weight).
abbreviated as wt%). Here, the reason why the concentration of the polycarbonate is limited to 3 to 40 wt% is that the productivity of the powdery polycarbonate is too low when it is less than 3 wt%, while the flowability of the organic solvent solution is lowered when it exceeds 40 wt%. This is because it becomes difficult to introduce the mixture into the mixing nozzle.

The type of the above polycarbonate is not particularly limited, and various polycarbonates obtained by the reaction of a dihydric phenol with phosgene or a carbonate compound can be used. Examples of the dihydric phenol and the carbonic acid ester compound are as follows.

Dihydric phenol 2,2'-bis (4-hydroxyphenyl) propane (bisphenol A), bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) Naphthylmethane, bis (4-hydroxyphenyl)-(4-isopropylphenyl) methane, diphenyl-bis (4-hydroxyphenyl) methane, bis (3,5-dichloro-4-)
Hydroxyphenyl) methane, bis (3,5-dimethyl-4-hydroxyphenyl) methane, 1,1-bis (4
-Hydroxyphenyl) ethane, 1-naphthyl-1,1
-Bis (4-hydroxyphenyl) ethane, 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane,
1,2-bis (4-hydroxyphenyl) ethane, 2-
Methyl-1,1-bis (4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 1-ethyl-1,1-bis (4
-Hydroxyphenyl) propane, 2,2-bis (3,3
5-dichloro-4-hydroxyphenyl) propane,
2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4)
-Hydroxyphenyl) propane, 2,2-bis (3-
Methyl-4-hydroxyphenyl) propane, 2,2-
Bis (3-fluoro-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) butane,
3,2-bis (4-hydroxyphenyl) butane, 1,
4-bis (4-hydroxyphenyl) butane, 2,2-
Bis (4-hydroxyphenyl) pentane, 4-methyl-2,2-bis (4-hydroxyphenyl) pentane,
1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (3,5-dichloro-4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) hexane, 4,4-bis Dihydroxy such as (4-hydroxyphenyl) heptane, 2,2-bis (4-hydroxyphenyl) nonane, 1,10-bis (4-hydroxyphenyl) decane and 1,1-bis (4-hydroxyphenyl) cyclododecane Aryl alkanes; bis (4-hydroxyphenyl) sulfone, bis (3,3
Dihydroxyaryl sulfones such as 5-dimethyl-4-hydroxyphenyl) sulfone and bis (3-chloro-4-hydroxyphenyl) sulfone; bis (4-hydroxyphenyl) ether and bis (3,5-dimethyl-4-hydroxy) Dihydroxy aryl ethers such as phenyl) ether; 4,4′-dihydroxybenzophenone and 3,
Dihydroxy aryl ketones such as 3 ', 5,5'-tetramethyl-4,4-dihydroxybenzophenone; bis (4-hydroxyphenyl) sulfide, bis (3
-Methyl-4-hydroxyphenyl) sulfide and bis (3,5-dimethyl-4-hydroxyphenyl) sulfide and other dihydroxyaryl sulfides; bis (4-hydroxyphenyl) sulfoxide and other dihydroxyaryl sulfoxides; 4,4 ' -Dihydroxydiphenyls such as dihydroxydiphenyl; dihydroxybenzenes such as hydroquinone, resorcinol and methylhydroquinone; dihydroxynaphthalenes such as 1,5-dihydroxynaphthalene and 2,6-dihydroxynaphthalene; and the like.

Carbonate ester compounds Diaryl carbonates such as diphenyl carbonate,
Dialkyl carbonates such as dimethyl carbonate and diethyl carbonate.

The type of organic solvent is not particularly limited as long as it dissolves the polycarbonate and can be removed by evaporation by steam. As such an organic solvent, methylene chloride is preferable, but chloroform, carbon tetrachloride, dioxane, tetrahydrofuran or the like can also be used. These organic solvents may be used alone or as a mixture.

In the present invention, the above-mentioned organic solvent solution and steam are introduced into the mixing nozzle, and the polycarbonate is recovered as powder from the mixture injected from the mixing nozzle. The organic solvent solution and steam, as described above, the ratio of steam weight (W _S) and the weight of the organic solvent in the organic solvent solution and _{(W O) (W S /} W O) is 1 /
It is introduced into the mixing nozzle so that it becomes 10 to 1/5. W
_The reason for limiting _S / W _O to 1/10 to 1/5 is that W _S /
When W 2 _O is smaller than 1/10, the amount of the organic solvent remaining in the obtained powdery polycarbonate becomes too large, while when W _S / W _O is larger than 1/5, the bulk of the powdery polycarbonate obtained is large. This is because the density is too low.
Further, it is preferably 1/8 to 1/6.

It is preferable to use steam having a pressure (pressure at the time of introducing the nozzle) of 1 to 100 kg / cm ² and a temperature of 100 to 310 ° C. As the mixing nozzle into which the organic solvent solution and steam are introduced, any type can be used, but one having an ejector structure is preferable. Recovery of the polycarbonate from the mixture injected from the mixing nozzle is performed, for example, by introducing the injected mixture into a separator such as a gas-solid separation cyclone through a pipe and separating (recovering) the polycarbonate by this separator. You can In this case, the pipe connecting the mixing nozzle and the separator may be a straight pipe or a curved pipe.
The pipe diameter (inner diameter) is 5 mm to 25 cm, and the pipe length is 50 cm to 10 cm.
It is 00m. The ratio (L / D) of the pipe length (L) to the pipe diameter (inner diameter D) is limited to 100 to 10,000. If this ratio is less than 100, the evaporation of the organic solvent is insufficient, and 10
If it exceeds 000, the pressure loss becomes large, so that high-pressure steam is required as steam to be introduced into the mixing nozzle.

According to the present invention, when the polycarbonate organic solvent solution and steam are introduced into the mixing nozzle and the polycarbonate is recovered as powder from the mixture sprayed from the mixing nozzle, the concentration of the polycarbonate in the organic solvent solution is set to the above-mentioned value. provisions and as of, and at the time of introduction W _S
By defining / W 2 _O as described above, it becomes possible to easily obtain a powdery polycarbonate having a high bulk density and a small amount of residual solvent.

The present invention can also be applied as a part of the process for producing a polycarbonate by the interfacial polycondensation method. In this case, as the organic solvent solution of the polycarbonate mixed with steam, the organic solvent solution of the polycarbonate obtained by subjecting the emulsion solution obtained by the interfacial polycondensation reaction to washing and separation operations is used.

[0016]

Embodiments of the present invention will be described below. Example 1 Tufflon A2500 (trade name) manufactured by Idemitsu Petrochemical Co., Ltd. was used as a polycarbonate, and this was dissolved in methylene chloride (a special grade) manufactured by Hiroshima Wako Pure Chemical Industries, Ltd. A 13 wt% polycarbonate methylene chloride solution (hereinafter referred to as PCMC) was prepared. Then, with this PCMC, the pressure is 14 kg / cm ² and the temperature is 1
172.4 kg / hr and 2 with 95 ° C steam respectively
It was introduced into the mixing nozzle at the same time using a diaphragm type pump at a rate of 5 kg / hr. Weight of steam at this time (W
_S ) and the weight of methylene chloride (W _MC ) (W _S / W
_MC ) was 1/6. The mixing nozzle is shown in FIG.
The mixing nozzle having the structure shown in was used. This mixing nozzle 1
Includes a first nozzle 3 having a jet nozzle 2 and a second nozzle 4 arranged such that the inner wall of the jet nozzle of the first nozzle 3 is in contact with the outer wall of the jet nozzle. A mixing chamber 5 is formed in the internal space of the ejection beak of the first nozzle 3. Further, the ejection nozzle of the first nozzle 3 is provided with a through hole 6 communicating with the mixing chamber 5, and the through hole 6 is
It communicates with the PCMC supply pipe 7. The first nozzle 3
The outer diameter a of the spouting beaker is 50 mm, and the maximum diameter b of the mixing chamber 5 is 30
mm, from the tip of the second nozzle 4 to the ejection port 2 in the mixing chamber 5
The distance c to the end face on the side is 50 mm, and the diameter d of the narrowest part in the internal space of the second nozzle is 5 mm. This mixing nozzle 1
In, the PCMC introduced into the mixing chamber 5 through the PCMC supply pipe 7 and the through-hole 6 is mixed with the steam introduced into the mixing chamber 5 through the second nozzle 4 to form a mixture from the ejection port 2. Is jetted.

The mixture injected from the mixing nozzle 1 has an inner diameter (D) of 10 mm, a pipe length (L) of 10 m, and an L / D of 10.
Through a stainless steel pipe of 00, the internal volume is 0.3 m ³
Introduced into the cyclone. After operating for 1 hour, the target powdery polycarbonate was obtained from the lower part of the cyclone. Table 1 shows the bulk density of the obtained powdery polycarbonate and the residual amount of methylene chloride (hereinafter referred to as the residual MC amount). Furthermore, the obtained powdery polycarbonate was heated at 120 ° C. for 4 hours.
Amount of residual MC after drying for an hour (hereinafter, residual MC after drying
The amount) is also shown in Table 1.

Example 2 A powdery polycarbonate was obtained in the same manner as in Example 1 except that PCMC was introduced into the mixing nozzle at a rate of 215.5 kg / hr and W _S / W _MC was changed to 1 / 7.5. It was Table 1 shows the bulk density, residual MC amount and residual MC amount after drying of the obtained powdery polycarbonate.

Example 3 A powdery polycarbonate was obtained in the same manner as in Example 1 except that PCMC was introduced into the mixing nozzle at a rate of 258.6 kg / hr and W _S / W _MC was changed to 1/9. Table 1 shows the bulk density, residual MC amount and residual MC amount after drying of the obtained powdery polycarbonate.

Example 4 Carrying out except that the concentration of polycarbonate in PCMC was 8 wt%, this PCMC was introduced into the mixing nozzle at a rate of 203.8 kg / hr, and W _S / W _MC was set to 1 / 7.5. A powdery polycarbonate was obtained in the same manner as in Example 1. Table 1 shows the bulk density, residual MC amount and residual MC amount after drying of the obtained powdery polycarbonate.

Example 5 The concentration of polycarbonate in PCMC was set to 25 wt%,
The PCMC introduced into the mixing nozzle at a rate of 250 kg / _hr, except that the _W S / W _MC to 1 / 7.5 in the same manner as in Example 1 to obtain a powdery polycarbonate. Table 1 shows the bulk density, residual MC amount and residual MC amount after drying of the obtained powdery polycarbonate.

Example 6 The mixing nozzle is structurally the same as the mixing nozzle 1 shown in FIG. 1, and the outer diameter a of the spout of the first nozzle 3 is 150 m.
m, the maximum diameter b of the mixing chamber 5 is 90 mm, the distance c from the tip of the second nozzle 4 to the end face of the mixing chamber 5 on the ejection port 2 side is 100 mm, and the diameter d of the narrowest part in the internal space of the second nozzle
Using a mixing nozzle with a diameter of 15 mm,
PCMC with a concentration of 13 wt% and steam with a pressure of 14 kg / cm ² and a temperature of 195 ° C. were respectively applied for 1724 kg / h.
It was introduced at the same time using a diaphragm type pump at a rate of r, 200 kg / hr. W _S / W _{MC at} this time is 1 / 7.5
Met. Then, the mixture injected from the mixing nozzle has an inner diameter (D) of 30 mm, a pipe length (L) of 30 m, and L / D.
Through the stainless steel pipe of 1000, the internal volume is 2m
Introduced to ³ cyclones. After operating for 1 hour, the target powdery polycarbonate was obtained from the lower part of the cyclone. Table 1 shows the bulk density, residual MC amount and residual MC amount after drying of the obtained powdery polycarbonate.

Comparative Example 1 A powdery polycarbonate was obtained in the same manner as in Example 1 except that PCMC was introduced into the mixing nozzle at a rate of 114.9 kg / hr and W _S / W _MC was set to 1/4. Table 1 shows the bulk density, residual MC amount and residual MC amount after drying of the obtained powdery polycarbonate.

Comparative Example 2 A powdery polycarbonate was obtained in the same manner as in Example 1 except that PCMC was introduced into the mixing nozzle at a rate of 57.5 kg / hr and W _S / W _MC was halved. Table 1 shows the bulk density, residual MC amount and residual MC amount after drying of the obtained powdery polycarbonate.

Comparative Example 3 A powdery polycarbonate was obtained in the same manner as in Example 1 except that PCMC was introduced into the mixing nozzle at a rate of 344.8 kg / hr and W _S / W _MC was set to 1/12. Table 1 shows the bulk density, residual MC amount and residual MC amount after drying of the obtained powdery polycarbonate.

[0026]

[Table 1]

As is apparent from Table 1, the bulk densities of the powdery polycarbonates obtained in Examples 1 to 6 with W _S / W _MC within the limit of the present invention are 0.41 to 0. 5
It is 5. These values are the values of the bulk density (0.3) of the powdery polycarbonates obtained in Comparative Example 1 and Comparative Example 2 in which W _S / W _MC is larger than the upper limit of the limited range of the present invention.
Much larger than 5-0.25). In addition, Example 1
The residual MC amount of each powdery polycarbonate obtained in Example 6 was as small as 90 to 100 wtppm, and these values are the same as the residual MC amount (90 wtppm) of each powdery polycarbonate obtained in Comparative Example 1 and Comparative Example 2. Is equivalent. Further, regarding the residual MC amount after drying, the powdery polycarbonate obtained in any of the Examples was 10 as in the case of each powdery polycarbonate obtained in Comparative Example 1 and Comparative Example 2.
Very low, less than wtppm. The powdery polycarbonate of Comparative Example 3 obtained by setting W _S / W _MC to be smaller than the lower limit of the limiting range of the present invention has a large bulk density value of 0.50, but has a residual MC amount and a dry MC value after drying. The amount of residual MC is extremely large.

[0028]

As described above, according to the present invention,
A powdery polycarbonate having a high bulk density and a small amount of residual solvent can be obtained by a simple method. Therefore, with the powdery polycarbonate obtained by the present invention, it is possible to improve the volumetric efficiency of the processing equipment used for the post-treatment such as drying or storage, and thereby it is possible to improve the productivity of the polycarbonate product. .

[Brief description of drawings]

FIG. 1 is an end view showing a mixing nozzle used in an example.

[Explanation of symbols]

 1 Mixing Nozzle 2 Jet 3 First Nozzle 4 Second Nozzle 5 Mixing Chamber

Claims (2)

[Claims] 1. A method for producing a powdery polycarbonate in which an organic solvent solution of polycarbonate and steam are introduced into a mixing nozzle, the mixture injected from the mixing nozzle is introduced into a separator, and the polycarbonate is recovered as powder. The concentration of polycarbonate as an organic solvent solution is 3 to
Using an organic solvent solution of 40% by weight, the ratio (WS / WO) of the weight of the steam at the time of introduction (WS) to the weight of the organic solvent in the organic solvent solution (WS / WO) is 1/10 to 1
/ 5 and the piping connecting the mixing nozzle and separator
The ratio (L / D) of the pipe length (L) to the pipe diameter (inner diameter D) is 1
The method for producing a powdery polycarbonate is characterized in that it is from 00 to 10,000 . 2. A methylene chloride solution of polycarbonate is used as the organic solvent solution of polycarbonate.
The method for producing a powdery polycarbonate according to 1.