JPH05179003A - Production of granular material of polycarbonate - Google Patents

Abstract

PURPOSE:To provide a method for readily producing a granular material of a polycarbonate, having a small width of grain size distribution and excellent in drying efficiency, handleability, sanitary properties by dusting, stability, etc., in extrusion molding. CONSTITUTION:The objective method for producing a granular material of a polycarbonate is to add and mix an organic solvent in an amount so as to provide >=10 pts.wt. based on 100 pts.wt. polycarbonate and <=120 pts.wt. total amount of the organic solvent based on 100 pts.wt. polycarbonate with an aqueous slurry of a powdery or a granular material of the polycarbonate while stirring the aqueous slurry.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for granulating a polycarbonate, more specifically, a powdery granular polycarbonate having a narrow particle size distribution, drying efficiency, handleability, hygiene due to dust generation, stability during extrusion molding, etc. To a method for producing a polycarbonate granule excellent in heat resistance.

[0002]

2. Description of the Related Art Conventionally, as a method for obtaining a polycarbonate powder from an organic solvent solution of polycarbonate, the organic solvent solution of polycarbonate is put into warm water to remove the organic solvent and then left to stand for the organic solvent solution of polycarbonate. A method of gelling or crystallization to facilitate crushing and then crushing (Japanese Patent Publication No. 36-21033, Japanese Patent Publication No. 3).
8-22497, Japanese Patent Publication No. 40-12379, Japanese Patent Publication No. 45-9875, and Japanese Patent Publication No. 46-314.
No. 68) is known.

However, in the above-mentioned method of pulverizing by gelling or crystallizing, granular polycarbonate can be easily obtained by selecting the opening of the screen of the pulverizer, but this granular material has a particle size distribution. There is a problem that the residual solvent in the polycarbonate is large, because the width of the polycarbonate is large and the drying efficiency is very poor. Further, in order to improve the drying efficiency, if the opening of the screen of the crusher is made small and the particle size is made fine, there is a problem that handleability, hygiene due to dust generation, stability during extrusion molding, etc. are inferior. Is not a satisfactory method.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a method for easily producing a polycarbonate granule having a narrow particle size distribution, excellent drying efficiency, handleability, hygiene due to dust generation, stability during extrusion molding, and the like. The purpose is to provide.

The present inventor has conducted extensive studies to achieve the above object, and as a result, when an organic solvent was added and mixed into a water slurry of polycarbonate powder particles having different particle sizes mixed with stirring, only fine particles were bonded. However, it was found that a granular material having a uniform particle size was obtained, and that the desolvation efficiency did not decrease in spite of the large particle size of the granular material, and the present invention was accomplished.

[0006]

According to the present invention, 100 parts by weight of an organic solvent is added to an aqueous slurry of a polycarbonate powder in which the residual amount of the organic solvent in the polycarbonate is 100 parts by weight or less based on 100 parts by weight of the polycarbonate. The method is a method for producing a polycarbonate granule, which comprises adding 10 parts by weight or more to 100 parts by weight and 120 parts by weight or less of the total organic solvent to 100 parts by weight of the polycarbonate.

The polycarbonate used in the present invention may be one produced by any method, but the phosgene method in which the product is obtained in the form of powder is preferable. The phosgene method is a well-known method, and is obtained by polymerizing an oligomer obtained by reacting an aqueous solution of dihydric phenol with phosgene in the presence or absence of an organic solvent, in the presence of an organic solvent. In this method, the organic solvent is removed from the solution of the reaction product in an organic solvent to obtain a polycarbonate powder. In this method, a catalyst, a terminal stopper, a dihydric phenol antioxidant, and other additives can be used if necessary. Further, the obtained polycarbonate may be, for example, a branched polycarbonate obtained by reacting a trifunctional or higher polyfunctional aromatic compound, or may be a mixture of two or more kinds of polycarbonates. The degree of polymerization of the polycarbonate is not particularly limited as long as it is a slurry polycarbonate, and the repeating unit may be, for example, 2 to 10. Usually, those having a viscosity average molecular weight of 13,000 to 40,000 are used.

The dihydric phenol used here has the following general formula:

[0009]

[Chemical 1]

[Wherein R is a divalent aliphatic group having 1 to 15 carbon atoms, a phenyl-substituted aliphatic group, an alicyclic group,>S,> O,
> S = O,> SO ₂ or> CO, X ₁ and X ₂ are alkyl groups or halogen atoms, and m and n are 0, 1 or 2, and particularly 2 , 2-bis (4-hydroxyphenyl) propane [commonly called bisphenol A] is preferably used, and other dihydric phenols include, for example, bis (4-hydroxyphenyl) methane and 1,1-bis (4-hydroxyphenyl). Ethane,
1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) ether, and the like. Examples thereof include halogenated bisphenols such as 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane. These may be used alone or in combination of two or more.

In the present invention, the above polycarbonate is used as an aqueous slurry of powdery particles. As the water slurry of the polycarbonate powder, the polycarbonate powder obtained from the organic solvent solution of the polycarbonate produced by the phosgene method is obtained as a hot water slurry. Preference is given to using. Incidentally, the polycarbonate powder in the water slurry obtained from the organic solvent solution of polycarbonate, a considerable amount of the organic solvent remains,
If the amount of this residual organic solvent is too large, the allowable range of the amount of the organic solvent to be described later is narrow, large lumps are formed, or the particles become too coarse, and it becomes difficult to obtain a desired particle size. Polycarbonate 10 is the amount of residual organic solvent
It should be 100 parts by weight or less relative to 0 parts by weight. Further, water may be added to the dry polycarbonate powder and used. The concentration of the polycarbonate in the slurry (PC / PC + organic solvent + water) should be such that it can be mixed by ordinary stirring, and it is usually used in the range of 10 to 50% by weight.

The organic solvent used in the present invention is WFCHRIST.
OPHER, DWFOX "Polycarbonates" 1962, p. Three
"Good Solvents" and "Fair" in Table 3-1
Solvents "are applicable solvents, such as ethane tetrachloride, methylene chloride, 1,2-dichloroethylene, chloroform, dioxane, tetrahydrofuran and the like, alone or as a mixed solvent. Particularly, as an aqueous slurry of polycarbonate powder, When using a slurry obtained from an organic solvent solution of polycarbonate, it is preferred to use the same solvent as the organic solvent solution.

If the amount of the organic solvent added to the water slurry of the polycarbonate powder is too small, the desired granulation effect cannot be obtained, so at least 10 parts by weight should be added to 100 parts by weight of the polycarbonate. On the other hand, if the amount is too large, a large lump will be formed or the particles will be too coarse. Therefore, the total amount of the organic solvent remaining in the polycarbonate powder in the slurry and the added organic solvent is 100 parts by weight of the polycarbonate. It should not exceed 120 parts by weight.

If the temperature of the slurry at the time of adding the organic solvent is too high, the organic solvent will bump and cause troubles, or the total amount of the organic solvent will be small, and the desired granulation effect will not be obtained. The temperature is not higher than the boiling point of the solvent by 20 ° C., preferably not higher than 5 ° C., particularly preferably not higher than the boiling point. The mixing after the addition of the organic solvent may be a batch type or a continuous type, a circulation type, or a type in which a pulverization step is incorporated in the circulation. The mixing may be carried out at normal pressure or under pressure. Mixing time after addition is usually 5 minutes to 3
Mixing for 0 minutes is sufficient.

In adding the organic solvent, the non- or poor solvent for the polycarbonate may be added simultaneously or separately. It is preferable to add a non- or poor solvent because the amount of the organic solvent remaining in the obtained granule can be significantly reduced.

The non- or poor solvent used here is WFCHRI.
STOPHER, DWFOX "Polycarbonates" 1962, p.
32 Table 3-1 classification "Poor Solvents", "Ve
Solvents corresponding to “ry Poor Solvents” and “Non Solvents” include single or mixed solvents such as acetone, heptane, benzene, toluene, etc. The amount of non- or poor solvent used may be in a wide range. However, it is usually 0 to 150 parts by weight with respect to 100 parts by weight of polycarbonate.

[0017]

EXAMPLES The present invention will be further described with reference to the following examples. The parts in the examples mean parts by weight, and% means% by weight.
Means The average particle diameter and n in the Rosin-Rammler formula, which are evaluation items, are the Granular Handbook edited by the Japan Powder Industry Association, Part I, 2
The measurement was performed according to the particle size measurement method described in Chapter 2.4. It should be noted that n in the Rosin-Rammler formula serves as a guide for the particle size distribution, and a larger value indicates that the width of the particle size distribution is narrower. The chlorine content is parts by weight relative to 100 parts by weight of polycarbonate. Before drying, the sample was pyrolyzed at 180 ° C. using an aqueous solution of caustic soda and then subjected to chlorine analysis by the Horhard method. After drying, a total organic halogen analyzer [Mitsubishi Kasei Co., Ltd.
Manufactured by TOX].

[0018]

Example 1 1000 parts of a 15% methylene chloride solution of a bisphenol A polycarbonate having a viscosity average molecular weight of 23500, which was produced and purified by the phosgenation method, was added to 40 parts.
A kneader containing 50 parts of warm water at -42 ° C was charged with steam having a vapor pressure of 3 kg / cm ² for 1.5 hours at a rate capable of maintaining a mochi state under stirring. After stopping the addition of steam to cause gelation, coarse pulverization was performed. The methylene chloride content of this coarsely pulverized product was 70 parts based on 100 parts of polycarbonate. This coarsely pulverized product was made into powder and granules by a hammer mill with a screen having an opening of 4 mm, and water was added thereto to obtain a slurry having a polycarbonate concentration of 25%. This slurry is referred to as slurry A.

400 parts of this slurry A (100 parts of polycarbonate) was put into a stirring and mixing tank, 40 parts of methylene chloride was added thereto at 35 ° C. under stirring for 5 minutes, and after mixing for 20 minutes, steam having a vapor pressure of 3 kg / cm ² was added. It was distilled by blowing at 70 ° C for 1 hour, dehydrated by a centrifugal separator, and then dried by a fluidized dryer at 145 ° C for 8 hours to obtain a polycarbonate granular material. Table 1 shows the evaluation results (average particle size, rosin Ramlar n, chlorine content) of this granular material.

[0020]

Example 2 Slurry A40 produced in Example 1
0 part was put into a stirring and mixing tank, a mixed solvent of 40 parts of methylene chloride and 20 parts of heptane was added over 5 minutes under stirring at 35 ° C., and after mixing for 20 minutes, steam distillation was carried out in the same manner as in Example 1,
Dehydrated and dried to obtain polycarbonate granules. The evaluation results of this granular material are shown in Table 1.

[0021]

Comparative Example 1 Slurry A40 produced in Example 1
0 parts was put into a stirring and mixing tank, methylene chloride was not added,
Other conditions were the same as in Example 1 to obtain a polycarbonate powder. The evaluation results of the powder and granules are shown in Table 1.

[0022]

Example 3 Slurry A40 produced in Example 1
Pour 0 parts into a stirring and mixing tank, add a mixed solvent of 40 parts of methylene chloride and 20 parts of heptane for 5 minutes under stirring at 35 ° C., mix for 20 minutes, and immediately dehydrate with a centrifuge without steam distillation. Then, it was dried at 145 ° C. for 8 hours with a fluid dryer to obtain polycarbonate granules. The evaluation results of this granular material are shown in Table 1.

[0023]

[Example 4] 100 parts of the polycarbonate powder obtained in Comparative Example 1 was put into a stirring and mixing tank containing 300 parts of water to prepare a slurry having a concentration of 25%, and 40 parts of methylene chloride and heptane were stirred at 35 ° C under stirring. 20 parts of the mixed solvent was added over 5 minutes, and after mixing for 20 minutes, steam distillation, dehydration and drying were carried out in the same manner as in Example 1 to obtain polycarbonate granules. The evaluation results of this granular material are shown in Table 1.

[0024]

[Comparative Example 2] 100 parts of the polycarbonate powder obtained in Comparative Example 1 was put into a stirring and mixing tank containing 300 parts of water to form a slurry having a concentration of 25%, and 150 parts of methylene chloride was stirred at 35 ° C under stirring. It was added in 5 minutes and mixed for 20 minutes, but large lumps were generated and evaluation could not be made.

[0025]

EXAMPLE 5 1000 parts of a 15% methylene chloride solution of a bisphenol A polycarbonate having a viscosity average molecular weight of 15,000, which was produced and purified by the phosgenation method, was added to 40 parts.
A kneader containing 50 parts of warm water at -42 ° C was charged with steam having a vapor pressure of 3 kg / cm ² for 1.5 hours at a rate capable of maintaining a mochi state under stirring. After stopping the addition of steam to cause gelation, coarse pulverization was performed. The methylene chloride content of this coarsely pulverized product was 70 parts based on 100 parts of polycarbonate. This coarsely pulverized product was made into powder and granules by a hammer mill with a screen having an opening of 4 mm, and water was added to this to obtain a slurry having a polycarbonate concentration of 25%. This slurry is referred to as slurry B.

400 parts of this slurry B was put into a stirring and mixing tank, 40 parts of methylene chloride was added under stirring at 35 ° C. for 5 minutes, mixed for 20 minutes, and then steam distillation, dehydration and drying were carried out in the same manner as in Example 1. Polycarbonate granules were obtained with the evaluation results of the granules shown in Table 1.

[0027]

Comparative Example 3 A polycarbonate powder was obtained in the same manner as in Comparative Example 1 except that Slurry B was used instead of Slurry A. The evaluation results of the powder and granules are shown in Table 1.

[0028]

[Table 1]

[0029]

Example 6 1000 parts of a 15% methylene chloride solution of a bisphenol A polycarbonate having a viscosity average molecular weight of 23500, which was produced and purified by the phosgenation method, and 200 parts of heptane were mixed at a rate of 40 to 42 ° C. at the same speed.
In a kneader containing 50 parts of the warm water of 1.5, steam with a steam pressure of 3 kg / cm ² and 1.5 at a speed that can maintain the rice cake state under stirring.
Turned on in time. After stopping the addition of steam to cause gelation, coarse pulverization was performed. The methylene chloride content of this coarsely pulverized product was 35 parts based on 100 parts of polycarbonate.
This coarsely crushed product was made into powder and granules by a hammer mill with a screen having an opening of 4 mm, and water was added to obtain a slurry having a polycarbonate concentration of 25%.

400 parts of this slurry was put into a stirring and mixing tank, 40 parts of methylene chloride was added under stirring at 35 ° C. for 5 minutes, mixed for 20 minutes, and then steam distilled, dehydrated and dried in the same manner as in Example 1. A polycarbonate granule was obtained. The obtained granules had an average particle size of 1.3 mm and a rosin lambler n of 2.3.
1. The chlorine content was 0.00120 parts.

[0031]

EFFECTS OF THE INVENTION According to the method of the present invention, a granular material having a narrow particle size distribution of polycarbonate, containing a small amount of an organic solvent, being easy to handle, hygienic due to dust generation, stability in extrusion molding, and the like. Can be manufactured, and the industrial effect produced by the product is exceptional.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Aihara 1-6-21 Nishishinbashi, Minato-ku, Tokyo Teijin Kasei Co., Ltd.

Claims (1)

[Claims] 1. A residual amount of organic solvent in polycarbonate is 100 parts by weight or less with respect to 100 parts by weight of polycarbonate. And the total amount of organic solvent is polycarbonate 100
A method for producing a polycarbonate granule, comprising adding and mixing in an amount of 120 parts by weight or less with respect to parts by weight.