JPH0940785A - Production of particulate polycarbonate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a low residual solvent content and a heightened bulk density and improve dryability and handleability by mixing an organic solvent solution of a polycarbonate resin with water under special conditions and then removing the organic solvent to obtain particles of the resin. SOLUTION: A good solvent for a polycarbonate resin having a viscosity - average mol.wt. of 13,000-100,000 is mixed with a poor solvent therefor in a weight ratio of 10/0 to 6/4 to obtain an organic solvent. 4-27wt.% the polycarbonate resin is dissolved in the organic solvent and mixed with water in a weight ratio of 1/100 to 90/10. The resulting mixture is stirred under pressure at a linear speed of l-100m/s to obtain an O/W suspension. This suspension is heated to 90-105 deg.C to remove the organic solvent. The resulting particles are dried at 100-155 deg.C for 3-15hr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polycarbonate resin particles, and more specifically, a mixture of an organic solvent solution of polycarbonate and water is suspended at a specific flow rate to heat the organic solvent under heating. It is a method of removing and granulating. According to the present invention, the amount of residual solvent in the obtained granules is extremely small, the drying is easy, the bulk density is high, the handling is easy, and high quality polycarbonate resin granules can be obtained.

[0002]

2. Description of the Related Art Polycarbonate is a thermoplastic resin having excellent mechanical strength, impact resistance, transparency and heat resistance.
It is an engineering plastic that can be processed by various molding methods such as injection molding, extrusion molding, and vacuum molding, and is used in various fields for various industrial applications.

Polycarbonate resin production methods are roughly classified into a melting method (transesterification method) and a solution method. The solution methods are classified into an interfacial polymerization method and a pyridine method. Current,
Industrially, it is mainly produced by the interfacial polymerization method, but in the interfacial polymerization method, the polycarbonate is polymerized as an organic solvent solution, and in the process of obtaining polycarbonate resin particles from the obtained organic solvent solution, an organic solvent is used. Is required to be removed.

[0004] Conventionally, as a method for removing a solvent from an organic solvent solution of polycarbonate to obtain a polycarbonate granule, as described in JP-B-45-9875, a gel is formed in warm water and then pulverized. The method is generally used. However, in the granules produced by this method, a large amount of the organic solvent remains in the obtained granules, and the drying step becomes complicated for the removal thereof.

Japanese Patent Publication No. 4-71412, Japanese Patent Laid-Open No. 4-712
In 202427, a method for producing an aqueous slurry liquid of polycarbonate solid particles by adding a solidifying solvent to a polycarbonate resin solution, adding the mixture solution to hot water under heating, and performing wet pulverization is disclosed. Although disclosed, if the polycarbonate resin solution is not efficiently dispersed in warm water, a problem that lumpy solid matter is generated occurs.

In Japanese Patent Publication No. 4-55810, a methylene chloride solution of polycarbonate is introduced into warm water under stirring to generate polycarbonate resin granules in the stirring flow, and a narrow flow path is formed in the stirring flow of warm water. There is disclosed a method of providing a shearing force by rotating the stirring blade at a high speed in this flow path while being provided. In this method, the bulk density of the obtained particles is small because a high shearing force is applied to the polycarbonate resin liquid.

[0007] In JP-A-59-133228, a method of continuously supplying a methylene chloride solution of polycarbonate to a granulation tank and heating while maintaining a suspension state to evaporate methylene chloride to produce a granular body Is disclosed. In this method, since a suspension state is generated in the granulation tank, strong stirring power is required, and the resin solution particles dispersed in the granulation tank are re-adhered to each other to form a solid mass. It causes such troubles and is not preferable.

[0008]

As a method for obtaining particles from an organic solvent solution of polycarbonate (hereinafter sometimes referred to as a resin solution), it is not preferable to remove the solvent directly from the organic solvent solution from the viewpoint of energy efficiency. It is more preferable to indirectly remove the solvent by adding an organic solvent solution of polycarbonate to a poor solvent such as water. However, when the polycarbonate resin solution is poured into water under stirring, it is dispersed to some extent, but troubles of adhesion of the resin to the stirring tank or the stirrer occur, and the obtained particulate matter contains a large amount of organic solvent, so long drying time is required. I need.

In view of the above circumstances, the present invention is to obtain a high-quality polycarbonate resin granule having a very small amount of residual solvent in the obtained granule, easy drying, high bulk density and easy handling. .

[0010]

[Means for Solving the Problems] The present inventors have made a mixture of an organic solvent solution of polycarbonate and water into a suspension state at a specific flow rate to prevent troubles of resin adhesion to a stirring tank or a stirrer. The present invention has been completed, paying attention to the fact that there is no occurrence, etc., and it is extremely easy to granulate.

That is, according to the present invention, a mixed liquid of an organic solvent solution of a polycarbonate resin and water is pressurized to 1 to 100 m.
The present invention relates to a method for producing a polycarbonate resin particle, which comprises mixing at a linear velocity of / sec to form a suspended state, heating the obtained suspension to remove the organic solvent, and granulating.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a good solvent and a poor solvent for polycarbonate are used as an organic solvent solution of a polycarbonate resin, and the ratio of the good solvent and the poor solvent is 10: 0 to 6: 4 by weight. Is. The mixing ratio of the polycarbonate resin solution and water is 1: 100 to 90:10 by weight, and the suspension of the polycarbonate resin solution and water is an oil-in-water (O / W) suspension type. It is a suspension. According to the method of the present invention, the organic solvent is removed from this suspension to obtain a resin slurry, which is then dried to obtain resin particles.

The polycarbonate resin in the present invention is
A method similar to the conventional method for producing a polycarbonate resin, that is, an interfacial polymerization method, a method produced by a solution method such as a pyridine method, which contains a dihydric phenol compound as a main component,
Aromatic homo- or copolycarbonate resins prepared by reacting phosgene with a small amount of a molecular weight modifier and optionally a branching agent. Those having a viscosity average molecular weight of 13,000 to 100,000, such as those having a long-chain alkyl group introduced at the end.

Furthermore, a polycarbonate resin having a carbon-carbon double bond and other graftable points as an end terminating agent or a comonomer is produced and grafted with styrene or the like, or polystyrene or the like with a phenolic hydroxyl group, other Any of those obtained by copolymerizing a compound having a graft polymerization initiation point of a polycarbonate resin and those obtained by graft polymerization of a polycarbonate resin therewith can be used. Examples of commonly used aromatic polycarbonate resins include polycarbonates containing bisphenol A as a main raw material.
And a polycarbonate copolymer obtained by using tetrabromobisphenol A (TBA) in combination, a branched product thereof, or a product modified with a long-chain alkyl at the terminal.

Preferred dihydric phenol compounds used in the method for producing the polycarbonate resin of the present invention are specifically bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether and bis (4-hydroxyphenyl) methane. 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 (bisphenol A; BPA), 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane 2 (TBA), 2-bis ( 4-hydroxyphenyl)
Butane, 1,1-bis (4-hydroxyphenyl) cyclohexane (bisphenol Z; BPZ), 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-methylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, Bis (4-hydroxyphenyl) diphenylmethane, α, ω-bis [3-
Examples are (O-hydroxyphenyl) propyl] polydimethylsiloxane (PDS) and biphenol.
You may use these in combination of 2 or more types. Among them, those selected from bisphenol A, bisphenol Z, TBA and PDS are preferable.

Examples of the terminal terminator or molecular weight regulator include compounds having a monovalent phenolic hydroxyl group. In addition to ordinary phenol, P-tert-butylphenol, tribromophenol, etc., long-chain alkylphenols and aliphatic carboxylic acids. Examples thereof include chloride, aliphatic carboxylic acid, aromatic carboxylic acid, aromatic acid chloride, hydroxybenzoic acid alkyl ester, alkyl ether phenol and the like. Further, an end stopper having a reactive double bond can also be used. Examples of such compounds include unsaturated carboxylic acids such as acrylic acid, vinyl acetic acid, 2-pentenoic acid, 3-pentenoic acid, 5-hexenoic acid, 9-undecenoic acid; acrylic acid chloride, sorbic acid chloride, allyl alcohol. Acid chlorides or chloroformates such as chlorochloroformate, isopropenylphenol chloroformate or hydroxystyrene chloroformate; isopropenylphenol, hydroxystyrene, hydroxyphenylmaleimide, hydroxybenzoic acid allyl ester or hydroxybenzoic acid methylallyl ester Examples thereof include phenols having an unsaturated group. These compounds may be used in combination with a usual end-stopping agent, and are usually 1 to 25 mol%, preferably 1.5 to 10 mol% based on 1 mol of the above dihydric phenol compound. Used in the range.

As the solvent used in the reaction, methylene chloride, 1,2-dichloroethane, chloroform,
Chlorinated hydrocarbons such as 1,1,1-trichloroethane and carbon tetrachloride; aromatic hydrocarbons such as benzene; ether compounds such as diethyl ether; and two or more kinds of these organic solvents. It is also possible to mix and use. In addition, if desired, solvents other than the above, such as ethers, ketones, esters, and nitriles, which have an affinity for water may be used within the limit that the mixed solvent system is not completely compatible with water.

Further, a branching agent is added in an amount of 0.01 to 3 mol%, particularly 0.1 to 1.
A branched polycarbonate can also be used in combination within the range of 0 mol%. As a branching agent, phloroglucin,
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) benzol, 1,1,1-tri (4-hydroxyphenyl) ethane, 2,6-bis (2-hydroxy-5-methylbenzyl) -4-methylphenol , Α, α ′, α ″ -tri (4-hydroxyphenyl) -1,3,5-triisopropylbenzene and other polyhydroxy compounds, and 3,3-bis (4-hydroxyphenyl) oxindole ( = Isatin bisphenol), 5-chloroisatin bisphenol, 5,7-dichloroisatin bisphenol, 5-bromoisatin bisphenol and the like.

The solvent solution is separated from the polycarbonate resin polymerization solution, the catalyst is removed, neutralized, washed with water, concentrated and the like, and further subjected to centrifugation or microfiltration to obtain a purified organic solvent solution of polycarbonate. Generally, the purified resin liquid concentration is 4 to 27% by weight.

In the present invention, a solution of a polycarbonate resin in an organic solvent is mixed with water, and the mixture is pressurized to 1 to 1
The organic solvent is removed by raising the temperature of the suspension obtained by applying a linear velocity of 00 m / s to form a suspended state. When the linear velocity is 1 m / s or less, the organic solvent solution and water are not sufficiently mixed, which is not preferable, and when the linear velocity exceeds 100 m / s, the particles in the suspension solution become too fine and the obtained granular particles are obtained. It is not preferable because the body becomes fine powder. When mixing the organic solvent of polycarbonate and water, 1 to 1 is prepared in advance.
It is preferable to have a linear velocity of 00 m / s because mixing can be performed efficiently.

Means for obtaining a suspension by mixing the above-mentioned organic solvent solution of polycarbonate with water include, for example, Nanomizer, Harmonizer (manufactured by Nanomizer Co., Ltd.), static mixer, sulzer mixer, orifice mixer and the like. Although exemplified, other materials may be used as long as they have the same effect.

A solid solution can be obtained by dropping an organic solvent solution of polycarbonate into warm water as it is, but when the organic solvent is a chlorine-based solvent such as dichloromethane, the chlorine-based solvent remaining in the granular material causes a thermal history. When it is received, it may cause a hydrolysis reaction to generate chlorine ions, which may adversely affect the heat resistance and other qualities of the polycarbonate. In order to prevent this, it is preferable to add a non-solvent or a poor solvent in advance for the purpose of improving the porosity of the produced granular material and removing the chlorine-based solvent as much as possible during drying. In this case, several tens to several hundreds of ppm of the non-solvent or the poor solvent remains in the dried granules, but since it volatilizes easily during extrusion molding, there is no particular problem in terms of quality.

As such non-solvent or poor solvent,
Examples of n-heptane, n-hexane, cyclohexane, benzene, toluene, xylene, water and the like are included, and particularly, n is used for the purpose of obtaining a granular material having a preferable porosity.
-Heptane, n-hexane, cyclohexane are preferred. As the addition amount of the non-solvent or the poor solvent, the ratio of the good solvent to the poor solvent relative to the polycarbonate is 10: 0.
It is preferable to select the weight ratio of 6: 4.

In the present invention, the polycarbonate resin particles are precipitated by raising the temperature of the suspension after mixing the organic solvent solution of polycarbonate with water to form a suspension. In order to make the mixture homogeneous, the mixing ratio of the organic solvent solution of polycarbonate and water is preferably 1: 100 to 90:10 by weight. Further, the suspension of the organic solvent solution of polycarbonate and water is preferably an oil-in-water dispersion type (O / W) suspension.

When a granular material is precipitated from a suspension obtained by mixing an organic solvent solution of polycarbonate with water, the temperature of the suspension is raised to 90 to 105 ° C. to remove the organic solvent. Is preferred. As the temperature rises, the organic solvent is volatilized and the solid content of the polycarbonate resin is deposited.

As a means for raising the temperature of the suspension, the suspension is put into a stirring tank with a steam jacket, and the suspension is heated by introducing steam, or it is kept at 90 to 105 ° C. in advance. It is possible to use a method in which the suspension is heated in warm water while being heated.

By the above method, the solvent in the granules is volatilized to obtain an aqueous slurry liquid of the polycarbonate resin granules. This is filtered to obtain a wet powder of the polycarbonate resin, and dried at 100 to 155 ° C. for 3 to 15 hours to obtain a dry powder.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto as long as the scope of the present invention is not exceeded.

Example 1 Polycarbonate resin (Upilon S- manufactured by Mitsubishi Gas Chemical Co., Inc.)
200 kg of 3000 natural powder) was dissolved in 800 kg of methylene chloride to prepare a 20 w / w% polycarbonate organic solvent solution. Using two plunger pumps, 100 liters / h of an organic solvent solution of polycarbonate and 800 liters / h of pure water at 45 ° C. were respectively pressed and mixed into a static mixer having an inner diameter of 27 mm and a length of 550 mm, An oil-in-water dispersion type suspension was prepared. At this time, the flow velocity of the suspension in the static mixer was a calculated value of 43.7 m / sec. Met.

This suspension was poured into hot water whose temperature had been raised to 85 ° C. in advance and stirred for 30 minutes to obtain an aqueous slurry liquid of polycarbonate resin particles. The residual methylene chloride concentration in the wet powder obtained by filtering this was quantified by gas chromatography analysis and found to be 0.32%. After drying the wet powder at 145 ° C. for 3 hours, the residual methylene chloride concentration in the powder was 3.0 ppm, the bulk specific gravity was 0.62 g / cc, and the particle size distribution measured 1
The content of 0 mesh on was 1.20% by weight, and the content of 80 mesh pass was 1.14% by weight.

Examples 2 to 6 In Example 1, the press-fitting flow rate of water into the static mixer was set to Example 2: 100 liter / h (flow rate: 9.70 m / sec) and Example 3: 300 liter / h, respectively. (Flow velocity: 19.4 m / s), Example 4: 500 liter / h (Flow velocity: 29.1 m / sec), Example 5: 1
300 liter / h (flow rate: 67.9 m / sec), Example 6: 1800 liter / h (flow rate: 92.2 m / s)
The same procedure as in Example 1 was carried out except that ec) was used. Table 1 shows the results.

[0032]

[Table 1]

COMPARATIVE EXAMPLE 1 In Example 1, the flow rate of the organic solvent solution of polycarbonate and water into the static mixer was 5 liters / h (flow rate in static mixer: 0.5).
(cm / sec), but the same procedure as in Example 1 was performed, but a homogeneous suspension was not obtained, and the organic layer and the aqueous layer were separated. In the obtained wet powder, lumps having a diameter of 1 cm or more were formed, and good powder was not obtained.

Comparative Example 2 Polycarbonate solution in organic solvent 40 used in Example 1
Liter at a rate of 20 liters / h at 95 ° C under stirring
Was dropped into 100 liters of hot water. The obtained water slurry solution was filtered to obtain a moist powder, and the residual methylene chloride concentration in the moist powder was quantified by gas chromatographic analysis and found to be 3.5%. 145 wet powder
The residual methylene chloride concentration in the powder after drying at 3 ° C. for 3 hours was 255 ppm, and the bulk specific gravity was 0.32 g /
cc, 10 mesh on content by particle size distribution measurement:
6. 10% by weight, 80 mesh pass content: 2.05% by weight.

Example 7 Example 1 was repeated, except that in the preparation of the organic solvent solution of polycarbonate, 200 kg of polycarbonate resin powder was dissolved in a mixed solution of 600 kg of methylene chloride and 200 kg of n-heptane.
I went in the same way. When the residual solvent concentration in the obtained wet powder was quantified by gas chromatographic analysis, n
-1.3% heptane and 0.22 methylene chloride.
%Met. The residual organic solvent concentration in the powder after drying the wet powder at 145 ° C. for 3 hours was 120 for n-heptane.
ppm, methylene chloride was 0.2 ppm, bulk specific gravity was 0.65 g / cc, 10 mesh on content by particle size distribution measurement: 0.85% by weight, 80 mesh pass content: 0.90% by weight. .

Comparative Example 3 Organic solvent solution 2 of polycarbonate used in Example 7
0 liter of homomixer (rotation speed: 1760 rp
When the temperature was raised to 97 ° C. while continuing the stirring, the aqueous slurry liquid of polycarbonate resin granules was obtained. When the residual solvent concentration in the wet powder obtained by filtering this was quantified by gas chromatographic analysis, n
-4.5% heptane, 1.37 methylene chloride.
%Met. After the wet powder was dried at 145 ° C. for 3 hours, the residual organic solvent concentration in the powder was 154 for n-heptane.
0 ppm, methylene chloride 65 ppm, when further dried at 145 ° C. for 10 hours, n-heptane 130 ppm, methylene chloride 14 ppm, bulk specific gravity 0.43 g / cc, particle size distribution measured 1
The content of 0 mesh on was 2.35% by weight, and the content of 80 mesh pass was 6.32% by weight.

Example 8 Example 1 was repeated except that in the preparation of the organic solvent solution of polycarbonate, 200 kg of polycarbonate resin powder was dissolved in a mixed solution of 500 kg of methylene chloride and 300 kg of n-heptane. I went the same way. When the residual solvent concentration in the obtained wet powder was quantified by gas chromatographic analysis, n-
1.4% heptane and 0.17% methylene chloride
Met. The residual organic solvent concentration in the powder after drying the wet powder at 145 ° C. for 3 hours was 90 pp for n-heptane.
m, methylene chloride was 0.1 ppm, the bulk specific gravity was 0.66 g / cc, the 10 mesh-on content by particle size distribution measurement was 0.83% by weight, and the 80 mesh pass content was 0.88% by weight. .

Example 9 Polycarbonate Resin (Upilon S-manufactured by Mitsubishi Gas Chemical Co., Inc.
200 kg of 3000 natural powder) was dissolved in a mixed solution of 700 kg of methylene chloride and 300 kg of n-hexane to prepare a 16.7 w / w% polycarbonate organic solvent solution. Inner diameter 36 mm, length 7,000 m
6 m of the organic solvent solution of polycarbonate using two plunger pumps into the static mixer.
00 liters / h and 200 liters / h of 45 ° C. pure water were press-fitted and mixed to obtain a water-in-oil dispersion type suspension.
At this time, the calculated flow rate of the suspension in the static mixer was 21.8 m / sec.

This suspension was poured into hot water whose temperature had been raised to 97 ° C. in advance and stirred for 30 minutes to obtain an aqueous slurry liquid of polycarbonate resin particles. When the residual solvent concentration in the wet powder obtained by filtering this was quantified by gas chromatographic analysis, methylene chloride was found to be 0.3.
5% and n-hexane were 1.3%. 1 wet powder
The residual solvent concentration in the powder after drying at 45 ° C. for 3 hours was 0.8 ppm for methylene chloride and 80 ppm for n-hexane, the bulk specific gravity was 0.63 g / cc, and the 10-mesh-on content measured by particle size distribution measurement. The content was 1.33% by weight and the content of 80 mesh pass was 1.24% by weight.

Example 10 Polycarbonate resin powder (Mitsubishi Gas Chemical's Iupilon Z-200 (a homopolymer of bisphenol Z), viscosity average molecular weight: 22000) (100 kg) was dissolved in a mixed solution of 600 kg of methylene chloride and 100 kg of n-heptane. , 12.5 w / w% polycarbonate in organic solvent was prepared. Inner diameter 36 mm, length 1000 mm
Of the organic solvent solution of polycarbonate into two static mixers using two plunger pumps.
Liter / hour and pure water 1000 liter / hour at 45 ° C. were respectively pressed and mixed to obtain an oil-in-water dispersion type suspension. At this time, the calculated flow rate of the suspension in the static mixer was 30.6 m / sec.

80 liters of this suspension was placed in a stirring tank with a stirrer having an internal volume of 100 liters, and the steam was introduced into the steam jacket while stirring to raise the temperature to 101 ° C., followed by stirring for 30 minutes to obtain polycarbonate. An aqueous slurry liquid of resin particles was obtained. When the residual solvent concentration in the wet powder obtained by filtering this was quantified by gas chromatographic analysis, methylene chloride was 0.20% and n-heptane was 8700 ppm. After the wet powder was dried at 145 ° C. for 3 hours, the residual solvent concentration in the powder was 0.2 ppm of methylene chloride,
The n-heptane concentration was 104 ppm, and the bulk specific gravity was 0.1.
61 g / cc, 10 mesh on content by particle size distribution measurement: 0.93% by weight, 80 mesh pass content: 1.
It was 02% by weight.

[0042]

According to the present invention, it is possible to obtain a polycarbonate resin granule by a simple operation and efficiently obtain a homogeneous granule having a large bulk density and a sharp particle size distribution. Further, the obtained granules have advantages that the residual solvent amount is small, the subsequent drying time can be shortened, and the manufacturing process can be simplified.

Claims (5)

[Claims] 1. A mixed solution of a polycarbonate resin in an organic solvent and water is mixed under pressure at a linear velocity of 1 to 100 m / sec to form a suspended state, and the resulting suspension is heated to form an organic solution. A method for producing polycarbonate resin granules, which comprises granulating by removing a solvent. 2. The method according to claim 1, wherein the organic solvent comprises a good solvent and a poor solvent for polycarbonate, and the weight ratio of the good solvent and the poor solvent is from 10: 0 to 6: 4. 3. The method according to claim 1, wherein the mixing ratio of the organic solvent solution of the polycarbonate resin and water is 1: 100 to 90:10 by weight. 4. The method according to any one of claims 1 to 3, wherein the suspension of the polycarbonate resin composed of an organic solvent and water is an oil-in-water dispersion (O / W) suspension. 5. The method according to claim 1, wherein the suspension is heated to 90 to 105 ° C.