JPH0676483B2 - Method for producing resin having carbonate bond - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a process for producing a resin having no carbonate in pellets and molded articles and having a carbonate bond having an excellent color tone.

[Conventional technology]

Phosgene usually contains 250 ppm to 2,000 ppm of carbon tetrachloride (CCl ₄ ) as described in JP-B-55-14044.

Using phosgene containing such CCl ₄ as a raw material,
When attempting to make a polymer using a methylene chloride solvent, most of the CCl ₄ dissolves in methylene chloride and, as a result, is included in the methylene chloride solution of the polymer.

When CCl ₄ remaining in the polymer solution is separated from the polymer and methylene chloride, the CCl ₄ is distributed to the polymer and methylene chloride in a ratio corresponding to the separation conditions.

This is also the case when the solvent methylene chloride contains CCl ₄ .

Further, industrially separated methylene chloride does not separate CCl ₄ and is usually reused as it is. Therefore, the concentration of CCl _{4 in} methylene chloride increases as the number of circulation increases. A polymer containing a halogen compound generates an acidic component when pelletized or heated during molding, and as described in JP-A-60-81245, mold corrosion of a molding machine (metal corrosion when the molding machine is stopped) However, in this case, it was prevented by adding a specific ester, and there was no knowledge of carbon tetrachloride.

Further, the color tone of pellets and molded pieces is not sufficiently satisfactory as the quality of the polymer such that the color tone is deteriorated when the kind of the heat stabilizer and the amount of the heat stabilizer added are small.

[Object of the Invention]

The present inventors have conducted a variety of studies to prevent the generation of pellets and generated pellets and acidic components at the time of molding, and to improve the color tone of pellets and molded pieces, and as a result, the main causative substance that exerts these adverse effects by but to investigate that the CCl ₄ contained in a methylene chloride solution of the polymer, the CCl ₄ concentration of CCl ₄ concentration of methylene chloride in the raw material phosgene below numerical values as shown in the following equation, Peretsuto of The present invention has been completed by knowing that it is possible to produce a resin having a carbonate bond which is excellent in the color tone of pellets and molded pieces without generating an acidic component during molding and has good color tone.

A + 5 · B <200 A: CCl ₄ concentration in phosgene (ppm) B: CCl ₄ concentration in methylene chloride (ppm) That is, the object of the present invention is to produce a resin having a carbonate bond with excellent quality. And its purpose is phosgene in the polymerization system and CCl _{4 in} methylene chloride.
The sum of the concentrations (ppm) is achieved by satisfying the above equation.

[Structure of Invention]

Examples of the resin having a carbonate bond, which is a target of the present invention, include thermoplastic resins produced by using phosgene such as polycarbonate, polyester polycarbonate, and polycarbonate carbamate as a raw material and using methylene chloride as an organic solvent.

The polycarbonate resin is a polymer or copolymer obtained by a phosgene method in which various dihydroxydiaryl compounds are reacted with phosgene, and a typical one is 2,2-bis (4-hydroxyphenyl). )
A polycarbonate resin produced from propane (bisphenol A) may be mentioned.

Examples of the dihydroxydiaryl compound include bisphenol A, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2
-Bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane 1,1-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5dibromophenyl) Enenyl) propane, 2,2-bis (4-hydroxy-
Bis (hydroxyaryl) alkanoic acids such as 3,5 dichlorophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, such as 1,1-bis (4-hydroxyphenyl) cyclohexane Dihydroxy diaryl ethers such as bis (hydroxyaryl) cycloalkanes, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethylphenyl ether, 4,4'-dihydroxy Diphenyl disulfides, such as diphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, 4,4'-dihydroxy diphenyl sulfoxide, 4,4'-dihydroxy Dihydroxydiaryl sulfoxides such as -3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxydiphenyl Sulfone, 4,
Examples thereof include dihydroxydiarylsulfones such as 4'-dihydroxy-3,3'-dimethyldiphenyl sulfone.

These may be used alone or in combination of two or more,
In addition to these, hydroquinone, resorcin, 4,4'-dihydroxydiphenyl and the like may be mixed and used.

The polyester polycarbonate resin is a copolymer obtained by the reaction of various dihydroxydiaryl compounds described in the section of polycarbonate resin, phosgene and acid chlorides (terephthalic acid chloride, isophthalic acid chloride, etc.). (JP-A-55-25427, JP-A-55-3
As a polycarbonate carbamate, it is a copolymer obtained by the reaction of piperazine (or dipiperidine), a dihydroxydiaryl compound and phosgene. (See JP-A-60-31527 and JP-A-60-35024) The CCl ₄ concentration in the raw material phosgene is usually 250 ppm to
There is 2000ppm. This CCl ₄ is dissolved in the methylene chloride used when producing the polymer and remains in the polymer solution. (The polymer concentration in the polymer solution is 5 to 30% by weight,
It is preferably 10 to 20% by weight. ) When CCl ₄ remaining in the polymer solution is separated from the polymer and methylene chloride, the CCl ₄ is distributed into the polymer and methylene chloride in a ratio corresponding to the separation conditions. Normally, in methylene chloride
Since CCl ₄ does not contain but is industrially recovered methylene chloride is used as without separating the CCl _4, CCl ₄ concentration in methylene chloride as the circulation number will increase will increase.

As described above, when a polymer produced in methylene chloride containing a large amount of CCl ₄ is pelletized, when a pellet is molded, and when an acidic component is generated from the pellet, the mold of the molding machine is corroded. Also, the color tone of pellets and molded pieces is not sufficiently satisfactory.

Therefore, it is preferable that the CCl ₄ concentration in the polymer solution before separating the methylene chloride from the polymer is as low as possible.

As a method of lowering the CCl ₄ concentration in the polymer solution, a method of reducing the carry-in of CCl ₄ by reducing the CCl ₄ concentration in the raw material phosgene, specifically, the adsorption removal of CCl ₄ by activated carbon or the removal of phosgene and CCl ₄ Examples include separation and removal of CCl ₄ from phosgene by distillation using the difference in boiling points.

Further, as a method of using methylene chloride having a low content of CCl ₄ , in the case where methylene chloride is continuously circulated, a part or all of the circulated methylene chloride is converted into methylene chloride by an operation such as distillation. There is a method to remove CCl ₄ contained in.

It does not matter which method removes CCl ₄ , but it is necessary to keep the CCl ₄ concentration in the polymerization system within the range of the following formula.

A + 5 · B <200 A: CCl ₄ concentration in phosgene (ppm) B: CCl ₄ concentration in methylene chloride (ppm) Preferably A + 5 · B <150, more preferably A + 5 · B <100.

Methylene chloride used here means methylene chloride and dichlorobenzene, chloroform, tetrachloroethane,
Chlorinated hydrocarbons such as trichloroethane, dichloroethane, 1,2-dichloroethylene, or dioxane,
Examples thereof include a mixture with tetrahydrofuran, acetophenone, toluene, xylene, cyclohexane, acetone, n-heptane, etc., but a mixture containing 60% or more of methylene chloride is preferable, and a mixture with 100% methylene chloride is particularly preferable.

Polymerization of the polymer is performed by an interfacial polymerization method of reacting phosgene or phosgene with an acid chloride in the presence of a disidroxydiaryl compound, a diamine compound, an organic solvent, water, and a caustic alkali, and an acid acceptor by dissolving a dihydroxydiaryl compound or a diamine compound. Solution polymerization method in which phosgene or phosgene and acid chloride are reacted in the following organic alkali and organic solvent.

The polymer solution after polymerization may be diluted with methylene chloride as needed for washing and purification. The term "polymerization system" as used in the present invention includes the above polymerization reaction and, in the case of diluting, up to the step of diluting. To remove impurities in the polymer solution, wash with an aqueous alkali solution, aqueous acid solution, water or the like. Washing is performed using a mixer / settler or a centrifugal extractor.

For pulverization of the polymer solution, the polymer solution is heated with a kneader to be pulverized while removing methylene chloride, or a polymer is precipitated by adding a non-solvent or the like.

Since the polymer contains methylene chloride, a non-solvent, etc., it is dried by a conventional method to remove these solvents.

〔Example〕

 Hereinafter, a specific description will be given with reference to examples.

Examples-1 to 3 and Comparative Examples 1 to 3 In order to remove CCl ₄ (concentration: 500 ppm) contained in phosgene, phosgene was liquefied into the flask of 3 and the overhead temperature was 8 using a Widmer rectification tube. Fractionation was performed for 4 hours at a reflux ratio of 1: 1 at ℃.

As a result, the concentration of CCl _{4 in} phosgene was 5 ppm at the top phosgene.
(1.66 kg) and the bottom phosgene of 1200 ppm (1.17 kg) were obtained.

Using the obtained overhead phosgene according to a conventional method (JP-A-61-61
A polycarbonate was produced. That is, 25 glass-lined containers equipped with a stirrer, a stirrer, a phosgene blow-in tube, a thermometer, and a discharge cock at the bottom have pure water 15.3, caustic soda 1.03 kg (25.7 mol), and sodium hydrosulfide. 3.0 g and bisphenol A (2,790 g, 12.2 mol) were sequentially added with stirring to completely dissolve them.

Then, 10 wt / vol% aqueous caustic soda solution 3.1 (7.65 mol) and methylene chloride 7.65 with CCl ₄ content of 5 ppm were added, and phosgene 1.38 kg (1
(3.9 mol) with stirring for 60 minutes, and then 66.7 g of paratersiaributylphenol and 3.1 g of triethylamine.
Was added and stirred for 1 hour to polymerize.

After completion of the polymerization, the lower organic phase was washed once with pure water,
Phosphoric acid (3.0%) was added for neutralization, and the mixture was washed with pure water three times and then heated to distill off methylene chloride to obtain a powdery polycarbonate.

The powdery polycarbonate was dried by a conventional method and then kneaded into pellets with a 20 mmφ extruder [manufactured by Tanabe Plastic Co., Ltd.] without adding additives such as a heat stabilizer. (Kneading temperature: 280 ℃, screw rotation speed: 40r.pm, kneading speed: 1.6kg / Hr, polymer retention time: 2 minutes) The shape of pellets produced is 1.3mmφ and 2.5mmL (length). Atsuta

The pellet was dried by a conventional method, and the YI (yellowness) was measured with a color difference meter [TC-55D type manufactured by Tokyo Denshoku Co., Ltd.]. As a result, the YI of the pellet was as good as 7.

The metal corrosion test was measured by the following method.

Injection molding method (molding temperature using a mold made of carbon steel (S55C)
After molding 200 sheets of a flat plate having a length of 7 cm, a width of 4 cm, and a thickness of 3.2 mm at 300 ° C., the used mold was left at room temperature for 24 hours, and the surface condition at that time was visually observed and evaluated. The evaluation index is as follows.

Evaluation 0: No rust generation 〃 1: Corrosion pitting 〃 2: Partial brown rust 〃 3: Brown rust generation on the entire surface The evaluation results of mold corrosion of the examples were good without invention of rust.

Further, the phosgene and / or methylene chloride, the 1 CCl so that CCl ₄ content shown in Table ₄ (produced by Wako Pure Chemical Industries, Ltd. reagent special grade) was further added below the row of connexion obtained in the same manner as in polymerization as above When the pellets were measured, the results were as shown in Table 1 below.

For comparison, the results when the value of A + 5 · B exceeds 200 ppm are also shown.

Example 4 In order to remove CCl ₄ (concentration: 500 ppm) contained in phosgene, phosgene was liquefied into 3 flasks and purified using a Widmer rectification tube at a column top temperature of 8 ° C. and a reflux ratio of 1: 0.5. I stayed.

As a result, the concentration of CCl _{4 in} phosgene was 50 pp at the top phosgene.
The thing of m was obtained.

Using the obtained phosgene, a polycarbonate was produced in the same manner as in Example 1.

That is, 25 glass-lined containers equipped with a stirrer, a stirrer, a phosgene blow-in tube, a thermometer, and a discharge cock at the bottom have pure water 15.3, caustic soda 1.03 kg (25.7 mol), and sodium hydrosulfide. 3.0 g and 2.79 kg (12.2 mol) of bisphenol A were sequentially added with stirring and completely dissolved.

Then, the methylene chloride 10 wt / vol% aqueous solution of caustic soda 3.1 and (7.65 mol) is free of CCl ₄ was added CCl ₄ CC
l ₄ methylene chloride 7.65 prepared to a concentration of 10ppm was added,
Phosgene 1.38kg while keeping the liquid temperature at 20 ℃ by external cooling
(13.9 mol) was blown in with stirring for 60 minutes, and then 66.7 g of paratersiaributylphenol and 3.1% of triethylamine.
g and were added and stirred for 1 hour to polymerize.

After completion of the polymerization, CCl ₄ was added to methylene chloride containing no CCl ₄ in the lower organic layer to adjust the CCl ₄ concentration to 10 ppm. After adding methylene chloride 10.1, wash with pure water once and then 10%
Phosphoric acid (3.0) was added for neutralization, followed by washing with pure water three times and then heating to distill off methylene chloride to obtain a powdery polycarbonate.

The distilled methylene chloride was cooled and collected to collect 95% of the charged methylene chloride. 10 of the recovered methylene chloride
% Is distilled to bring the concentration of CCl _{4 in} methylene chloride to 2 ppm or less. Recovered methylene chloride, distilled methylene chloride and deficient methylene chloride (5% of the charged methylene chloride is CCl ₄
Methylene chloride prepared by adding CCl ₄ to methylene chloride containing no methylene chloride to 10 ppm) was mixed and used as methylene chloride for polymerization and washing.

When the polymerization, washing and pulverization operations were repeated 6 times, CCl ₄ in the recovered methylene chloride became almost equilibrium at the 5th time, and 8 p
I got to pm. The powdery polycarbonate obtained by circulating methylene chloride 6 times is dried by a conventional method and then kneaded with a 20 mmφ extruder [manufactured by Tanabe Plastic Co., Ltd.] without adding additives such as heat stabilizers. Pelletized. (Kneading temperature: 280 ℃, screw rotation speed: 40r.pm, kneading speed: 1.6kg / Hr, polymer retention time: 2 minutes) The shape of the pellets produced is 1.3mmφ and 2.5mmL (length). Atsuta The pellet was dried by a conventional method, and subjected to YI and mold corrosion test in the same manner as in Example I.

The results are shown in Table 2 below.

Examples-5 and 6 The overhead liquid obtained in the same manner as in Example-4 (CCl _{4 in} phosgene)
The raw material phosgene was prepared by adding carbon tetrachloride to the CCl ₄ concentration below the second phosgene such as shown in table Toitadakieki) which was distilled at Uidoma rectification tube to remove.

Further, to prepare a solvent by adding carbon tetrachloride to the CCl ₄ concentration in the methylene chloride, such as shown in the following Table 2 in methylene chloride containing no CCl _4.

A polymer was produced in the same manner as in Example 4 by using phosgene and methylene chloride having the adjusted carbon tetrachloride concentration. A predetermined amount of the recovered methylene chloride was distilled and circulated for use, and when the CCl ₄ concentration in the recovered methylene chloride was in equilibrium, mold corrosion of the polymer obtained and color tone evaluation of pellets were performed.

The results are shown in Table 2 below. As a result, the value of A + 5B is 200
In the following cases, good results were obtained in the evaluation of mold corrosion and the color tone of pellets. In the formula, A is the concentration of CCl ₄ in phosgene (ppm), and B is the concentration of CCl _{4 in} methylene chloride (ppm).

Comparative Examples 4 to 6 Polymers were produced in the same manner as in Example 4 except that the concentration of CCl ₄ in phosgene was changed by circulating CCl _{4 in} methylene chloride. A predetermined amount of the recovered methylene chloride was circulated and used after distillation.When the CCl ₄ concentration in the recovered methylene chloride was in equilibrium, the mold corrosion of the polymer obtained and the evaluation of the color tone of the pellet were performed, and the following results were obtained. Obtained.

As a result, as described above, when the value of A + 5B was more than 200, good results could not be obtained in the evaluation of mold corrosion and the color tone of pellets. The results are also shown in Table 2.

[Advantages of the Invention] The powdered polycarbonate obtained in the present invention has no problems such as mold corrosion of a molding machine because it does not generate an acidic component when pelletized or heated during molding.

Moreover, since the mold corrosion disappeared when the molding machine was stopped and restarted, the rust adhering to the molding machine could not be removed. For this reason, a large amount of polymer was used to remove the rust of the molding machine, but this was not necessary and the loss of polymer was reduced.

The color tone of the produced pellets and molded pieces became stable and good color tone due to the decrease of CCl ₄ concentration, and it became possible to obtain almost satisfactory quality.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshiaki Otani Yoshiaki Otani 2447, Fujita, Hachimansai-ku, Kitakyushu, Fukuoka Prefecture 1 Mitsubishi Kasei Co., Ltd. Kurosaki Plant (72) Isao Akihara 2447 Fujita, Hachimansai-ku, Kitakyushu, Fukuoka Address No. 1 Kurosaki Plant of Mitsubishi Kasei Co., Ltd. (56) Reference JP 57-207620 (JP, A) JP 57-174318 (JP, A) JP 60-35024 (JP, A)

Claims (1)

[Claims] 1. In a method for producing a resin having a carbonate bond using methylene chloride as an organic solvent and phosgene as a raw material, the concentration of carbon tetrachloride (CCl ₄ ) in phosgene and methylene chloride in a polymerization system is as follows. A method for producing a resin having a carbonate bond, which comprises polymerizing so as to satisfy the formula. A + 5B <200 A: CCl ₄ concentration in phosgene (ppm) B: CCl ₄ concentration in methylene chloride (ppm)