JP3101157B2 - Method for producing polycarbonate molding material pellets - Google Patents

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 molding material pellets using an extruder . More specifically, pelletizing a polycarbonate powder having a good formability with a controlled morphology represented by an average particle diameter, a bulk density and a true specific gravity of the powder using an extruder.
Features of manufacturing polycarbonate molding material pellets
It is about the law .

[0002]

2. Description of the Related Art Polycarbonate is excellent in heat resistance, mechanical strength (particularly impact resistance), electrical characteristics, transparency, etc., and is used for various applications as engineering plastics. ing. Various molding methods such as extrusion molding, injection molding, and melt molding are employed for molding using this polycarbonate resin. In order to use this polycarbonate as a molding material, it is generally known that pellets or powders are used, but for applications such as compounding with other polymers, alloying or mixing various additives, Powders are preferred. Polycarbonates generally have a higher melting temperature than other polymers. Therefore, when molding using polycarbonate powder, in order to improve productivity and reduce thermal deterioration, it is required to have a molding property that can be melt-molded at a lower temperature and that is easy to bite into the screw during molding. Have been. For this purpose, for example, as a method for improving the polymer itself, various methods such as a method of using a copolymer modified by copolymerizing a comonomer or a method of improving by blending additives are adopted. Have been. However, when using a copolymer, the comonomer to be copolymerized is expensive,
In addition, when an additive is compounded, there is a drawback that the cost ratio of the additive is increased and the cost ratio is not just for the purpose of improving the moldability. In addition, the molding machine itself has been improved by providing a device for pushing into the screw or using a special screw. However, there is a problem in that the equipment cost is high and cannot be easily implemented.

[0003]

Means for Solving the Problems Accordingly, the present inventors have:
In view of the above points, the present inventors have intensively studied to solve the conventional problems and obtain a polycarbonate molding material having excellent moldability when molding using polycarbonate powder.
As a result, it has been found that the powder characteristics having specific values such as average particle size, bulk density, and true specific gravity can achieve the object of the present invention. The present invention has been completed based on such findings. That is, the present invention comprises a polycarbonate powder having a viscosity average molecular weight of 10,000 to 50,000, and as a powder characteristic, an average particle diameter of 0.2 to 5.0 m.
m, bulk density 0.2 to 0.6 g / cc and true specific gravity 0.6 to 1.
1g / cc polycarbonate powder as raw material
Polycarbonate characterized by being pelletized by a dispenser
It is intended to provide a method for producing a nate molding material pellet .

[0004] First, in the present invention, polycarbonate powder (hereinafter sometimes abbreviated as PC powder) can be obtained by various methods without requiring specific equipment and conditions for production. Particularly, those having pores inside are preferably used. The PC powder is usually
It has a viscosity average molecular weight of 10,000 to 50,000, preferably 15,000 to 45,000. If the viscosity average molecular weight is less than 10,000, the mechanical strength such as impact resistance may decrease, which is not preferable. On the other hand, if it exceeds 50,000, the melt viscosity increases, the fluidity decreases, and molding may be difficult. In the above preferred range, sufficient effects can be obtained on heat resistance and impact resistance as well as fluidity.

The above viscosity average molecular weight is from 10,000 to 50,000.
Among the 000 PC powders, those having a specific average particle size, bulk density, and true specific gravity are used as the powder characteristics in the present invention. That is, the average particle size of the PC powder of the present invention is usually 0.2 to 5.0 mm, preferably 0.3 to 3 mm. If the average particle size is less than 0.2 mm, although it depends on the particle size distribution of the powder, the amount of fine powder increases, and the powder rises up during molding, which is not preferable because it deteriorates the environment. In addition, it is not preferable because it may deposit in the hopper of the molding machine or stay in the screw biting portion, causing black spots or silver streaks. And 5.
If it exceeds 0 mm, it becomes difficult to handle the powder, and the biting into the screw often deteriorates, which is not preferable. In order to control the particle size of the PC powder, a method of confirming and controlling the control factor in each manufacturing method may be employed, and the obtained powder may be appropriately screened using a sieve having a desired size. You only need to divide them. Further, a method by pulverization can also be adopted. However, in the grinding method,
It should be noted that the bulk density may be significantly reduced due to the non-uniform shape of the powder.

Next, the bulk density of the PC powder is usually 0.2 to 0.2.
0.6 g / cc, preferably 0.3 to 0.55 g / cc. If the bulk density is less than 0.2 g / cc, the volume of the powder becomes large, and the throughput of the powder by the transport and the screw is remarkably reduced. On the other hand, if it exceeds 0.6 g / cc, the powder will be in a sufficiently tight state, and the moldability may be reduced. The bulk density of the PC powder is greatly affected by the outer shape (shape) of the powder. Generally, if the powder has a similar and uniform shape regardless of the particle size, the bulk density increases. If the shape is distorted and various shapes are used, the bulk density becomes smaller. Uniform and preferred powder shapes include spherical, prismoidal, and granular.
, Cubical, plate-like (plat
y), acicular and fibrous are not preferred.

There are various methods for forming the above-mentioned shape. In other words, there are 1) a method with uniform stirring (rolling granulation, coating granulation), 2) a method with coagulation stirring, and 3) compression granulation (pricketing, tableting). On the other hand, in crush granulation and spray granulation,
Generally, it is not preferable because the bulk density is reduced. As a preferable method for obtaining the powder having the above-mentioned shape, a method in which a polycarbonate solution is added while heating the powder in a container in which the powder is previously stirred and mixed, and tumbling granulation is performed. There is. Further, as a standard of the uniform stirring, it is desirable that there is no substantial dead portion in the stirring vessel, and further, the average residence time in the vessel is τ, and the average mixing time due to the circulation of the powder in the vessel is t. At this time, it is good to adjust so that τ / t ≧ 5, preferably τ / t ≧ 10. When τ / t is less than 5,
The powder is not preferable because it cannot receive a sufficient rolling granulation effect and often takes an irregular shape.

The true specific gravity of the PC powder is 0.6 to 1.1.
g / cc, preferably 0.6 to 1.0 g / cc. If the true specific gravity exceeds 1.1 g / cc, there is a possibility that the excellent molding characteristics aimed at by the present invention may not be obtained, which is not preferable. The true specific gravity of the powder greatly depends on the internal structure of the particles. That is, when the number of voids inside the particles increases, the true specific gravity decreases, and when the number of voids decreases, for example, in the case of polycarbonate, the maximum is 1.2 to 1.3 g / c.
c. Here, the true specific gravity of the powder is (weight of the granular material)
/ (Volume of granular material) (g / cc) and can be measured by a liquid immersion method or the like including the inner pores of the particles. When the measurement is performed with water or the like, since the surface tension is high, bubbles due to the surface shape are present, and an error is likely to occur, the measurement is generally performed using an organic solvent such as heptane or methanol. As a method of forming a suitable void in the particles of the powder, for example, 1) when granulating, as a third component in the polycarbonate solution, a method in which a poor solvent or water or the like is present 2) From the target powder Also, there is a method of producing fine powders and aggregating them (in this case, compression or using a binder), and a method using a poor solvent is particularly preferable. In the case of granulation using a poor solvent, the principle that voids are formed inside the particles is not clear, but due to the action of the poor solvent, fine precipitated polymer particles are formed and a phase-separated structure is formed. Thus, it is considered that powder having many voids is obtained. In order to control the true specific gravity of the powder, although it depends on the granulation method, when using the above preferable poor solvent, by increasing the poor solvent, the true specific gravity decreases, so If the amount is considered in advance, the true specific gravity can be easily controlled. In general, by performing the above method and the granulation method simultaneously,
A powder that meets the objects of the present invention can be obtained.

There are no particular restrictions on the production of PC powder having the above-mentioned powder characteristics, and various methods can be employed. For example, a desired powder can be obtained by using the following method. That is, a poor solvent is added to an organic solvent solution of polycarbonate,
Method of gelling and pulverizing while concentrating Add a poor solvent to the organic solvent solution of polycarbonate,
Method of pouring into warm water Add a poor solvent to the organic solvent solution of polycarbonate,
A method of directly adding a polycarbonate powder to a stirring field. A method of producing a fine polycarbonate powder in advance and compressing and granulating the same. A method of producing a fine polycarbonate powder in advance and rolling and granulating it. Among these, the method (1) is preferable because it can continuously and efficiently obtain a PC powder.

Next, the polycarbonate molding material of the present invention
As an example of obtaining a PC powder used in a method for producing a pellet, the above-mentioned method capable of efficiently obtaining a PC powder will be specifically described in detail. In this method,
An organic solvent solution of polycarbonate (hereinafter, may be abbreviated as a PC organic solvent solution) is placed in a container in which an already-evaporated polycarbonate granule is kept in an atmosphere in which the organic solvent evaporates and uniformly stirred. Supplying the poor solvent for the polycarbonate and evaporating the organic solvent while bringing the organic solvent solution into contact with the polycarbonate granules, thereby continuously and efficiently producing polycarbonate granules having voids therein. can do. Here, the PC organic solvent solution may be prepared by various methods, and is not particularly limited. For example, in the production of polycarbonate, a method usually used, that is, a polycarbonate produced by performing an interfacial polycondensation reaction in the presence of an alkali using a dihydroxy compound and phosgene, or an ester of a dihydroxy compound and a carbonic acid diester A PC organic solvent solution obtained by appropriately dissolving the polycarbonate produced by the exchange reaction in an organic solvent can be used. Further, the emulsion obtained in the process of the interfacial polycondensation reaction between the dihydroxy compound and phosgene can be separated into an aqueous phase and an organic phase, and the organic phase in which polycarbonate is dissolved can be used as a PC organic solvent solution, which is more efficient. preferable.

In the interfacial polycondensation reaction or transesterification reaction, there are various dihydroxy compounds. For example, aromatic dihydric phenols represented by the general formula (I)

[0012]

Embedded image

--O--, --CO--, --S--, --SO-- or --SO _2- , wherein R ¹ and R ² are each a hydrogen atom, a halogen atom or a monovalent hydrocarbon group; ³ and R ⁴ are each a hydrogen atom or a monovalent hydrocarbon group, and R ⁵ is a divalent hydrocarbon group. Also, m and n
Represents an integer of 1 to 4, respectively. ] The compound represented by this is mentioned.

Specific examples of such a compound include bis (4-hydroxyphenyl) methane; 1,1-bis (4
2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A); 2,2-bis (4-hydroxyphenyl) butane; 2,2-bis (4-hydroxyphenyl) octane; 2,2-bis (4-hydroxyphenyl) phenylmethane; 2,2-bis (4-hydroxy-1-methylphenyl) propane; 1,1-bis (4-hydroxy-t
-Butylphenyl) propane; 2,2-bis (4-hydroxy-3-bromophenyl) propane; 2,2-bis (4-hydroxy-3,5-tetramethylphenyl) propane; 2,2-bis (4 -Hydroxy-3-chlorophenyl) propane; 2,2-bis (4-hydroxy-
3,5-tetrachlorophenyl) propane; 2,2-bis (4-hydroxy-3,5-tetrabromophenyl)
Bis (hydroxyaryl) alkanes such as propane, 1,1-bis (4-hydroxyphenyl) cyclopentane; 1,1-bis (4-hydroxyphenyl) cyclohexane; 1,1-bis (4-hydroxyphenyl)
Bis (hydroxyaryl) cycloalkanes such as -3,5,5-trimethylcyclohexane, 4,4-dihydroxydiphenyl ether; dihydroxyaryl ethers such as 4,4'-dihydroxy-3,3'-dimethylphenyl ether; 4,4'-dihydroxydiphenyl sulfide; 4,4'-dihydroxy-3,
Dihydroxydiaryl sulfides such as 3'-dimethyldiphenyl sulfide; 4,4'-dihydroxydiphenyl sulphoxide; 4,4'-dihydroxy-3,
Dihydroxyarylsulfoxides such as 3′-dimethyldiphenylsulfoxide; 4,4′-dihydroxydiphenylsulfone; 4,4′-dihydroxy-3,
And dihydroxydiarylsulfones such as 3′-dimethyldiphenylsulfone.

There are various aliphatic divalent hydroxy compounds. For example, butane-1,4-diol; 2,2-dimethylpropane-1,3-diol;
Hexane-1,6-diol; diethylene glycol;
Triethylene glycol; tetraethylene glycol;
Octaethylene glycol; dipropylene glycol;
N, N-methyldiethanolamine; cyclohexane-
1,3-diol; cyclohexane-1,4-diol; 1,4-dimethylolcyclohexane; p-xylylene glycol; 2,2-bis- (4-hydroxycyclohexyl) -propane and ethoxy of a dihydric alcohol or phenol And propoxylation products, for example, bis-oxyethyl-bisphenol A; bis-oxyethyl-tetrachlorobisphenol A or bis-oxyethyl-tetrachlorohydroquinone.

On the other hand, in the transesterification reaction, there are various types of carbonic acid diester. For example, it is at least one compound selected from diaryl carbonate compounds, dialkyl carbonate compounds and alkylaryl carbonate compounds. Here, the diaryl carbonate compound has the general formula (II), the dialkyl carbonate compound has the general formula (III), and the alkylaryl carbonate compound has the general formula (IV).

[0017]

Embedded image

Wherein R ¹ is as defined above, and Ar ¹
Represents an aryl group. ] Is represented. Such diaryl carbonate compounds include, for example, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl)
Carbonate, di-m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate,
Bisphenol A bisphenyl carbonate and the like can be mentioned. Further, as the dialkyl carbonate compound, for example,
Examples thereof include diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, and bisphenol A bismethyl carbonate.
Examples of the alkylaryl carbonate compound include methyl phenyl carbonate, ethyl phenyl carbonate, butyl phenyl carbonate, cyclohexyl phenyl carbonate, and bisphenol A bismethyl carbonate. Among these, diphenyl carbonate is preferably used.

Examples of phosgene include phosgene and other phosgene derivatives such as triphosgene, phosgene dimer, bromophosgene, bisimidazole ketone, and bis (p-nitrophenyl) carbonate.

Further, in producing polycarbonate by the above-mentioned interfacial polycondensation reaction or transesterification reaction, monohydric phenols may be used as a terminal terminator (molecular weight regulator). Examples of such monohydric phenols include on-butylphenol;
Butylphenol; pn-butylphenol; o-isobutylphenol; m-isobutylphenol;
Isobutylphenol; ot-butylphenol; m
-T-butylphenol; pt-butylphenol;
mn-pentylphenol; mn-pentylphenol; pn-hexylphenol; mn-hexylphenol; pn-hexylphenol; o-cyclohexylphenol;
-Cyclohexylphenol; p-cyclohexylphenol; o-phenylphenol; m-phenylphenol; p-phenylphenol; on-nonylphenol; mn-nonylphenol; pn-nonylphenol; Cumylphenol; p-cumylphenol; o-naphthylphenol;
m-naphthylphenol; p-naphthylphenol;
2,6-di-t-butylphenol; 2,5-di-t-butyl
Butylphenol; 2,4-di-t-butylphenol; 3,5-di-t-butylphenol; 2,5-dicumylphenol; 3,5-dicumylphenol;

[0021]

Embedded image As a compound or a chroman derivative, for example,
formula

[0022]

Embedded image

And the like. Among such phenols, pt-butylphenol;
p-Cumylphenol; p-phenylphenol and the like are preferably used. Further, in order to impart heat resistance and flame retardancy to polycarbonate, trivalent or higher phenols or halogenophenols can be used.

In order to obtain a PC organic solvent solution by the interfacial polycondensation reaction using each of the above-mentioned raw materials, first, an alkali aqueous solution of the dihydroxy compound and the monohydric phenol used as needed is added, if necessary. An organic solvent for dissolving the polycarbonate is added, and phosgene is blown into this to cause an interfacial polycondensation reaction. Here, as the alkali used, a strong alkali such as sodium hydroxide and potassium hydroxide is preferable. As the organic solvent, besides methylene chloride, which is usually preferably used, for example, chlorinated solvents such as chloroform and chlorobenzene, as well as solvents such as dioxane and tetrahydrofuran, or a mixed solvent thereof can be used. Further, in the interfacial polycondensation reaction, it is preferable to use a catalyst in order to smoothly carry out the reaction. Catalysts that can be used include tertiary amines,
There are quaternary ammonium salts and the like, and specific examples include triethylamine, tri-n-butylamine, diethylaminopyridine, tetramethylammonium chloride and the like. In the present invention, in particular, triethylamine (TE
A) is preferred. After the completion of the interfacial polycondensation reaction, the obtained reaction mixture is separated into an organic solvent phase and an aqueous phase by a known method, and after washing the organic solvent phase, a clear polycarbonate organic solvent solution is obtained. Provided for body production.

The PC powder is obtained from the P powder obtained as described above.
It can be efficiently and easily produced by the above method using a C organic solvent solution. That is, the PC organic solvent solution is kept in an atmosphere in which the organic solvent evaporates, and is supplied into a container in which there is already prepared, already stirred polycarbonate granules, and a poor solvent for the polycarbonate is supplied. By evaporating the organic solvent while bringing the organic solvent solution into contact with the polycarbonate granules, it is possible to continuously and efficiently produce polycarbonate granules having voids therein. Here, the organic solvent is the same as that used in the production of polycarbonate. The poor solvent may be any solvent that does not substantially dissolve the polycarbonate. For example, aromatic compounds such as benzene, toluene, and xylene; alkanes such as pentane, hexane, heptane, and octane; ketones such as acetone and methyl ethyl ketone; or a mixed solvent thereof. Of these, alkanes having 5 to 10 carbon atoms are preferable because they can be easily removed from polycarbonate in terms of operation, cost, and the like. The poor solvent is usually supplied at a rate of 5 to 200% by weight, preferably 10 to 150% by weight, based on the organic solvent in the organic solvent solution.

On the other hand, when a ready-made polycarbonate is used, the PC organic solvent solution is used as an organic solvent that is substantially inert to the polycarbonate, is substantially stable at the use temperature, and dissolves the polycarbonate. It can be obtained by Here, as the organic solvent,
Considering the removal of the organic solvent from the polymer granules during the granulation process, it is preferable to use an organic solvent having a boiling point of 200 ° C. or lower. Examples of the organic solvent include, in addition to methylene chloride, which is usually preferably used, for example, chlorinated solvents such as chloroform and chlorobenzene, as well as solvents such as dioxane and tetrahydrofuran, or a mixed solvent thereof. The concentration of the polycarbonate dissolved in the organic solvent is usually 3 to 40% by weight, preferably 10 to 30% by weight. If the concentration is less than 3% by weight, the amount of the solvent to be recovered is increased, and the productivity is reduced, which is not efficient. On the other hand, if it exceeds 40% by weight, it becomes solid and the fluidity becomes low, and it is difficult to supply and operate the granulation container, which is not preferable. As described above, the polycarbonate powder obtained using the PC organic solvent solution and the poor solvent has pores therein, has the above-mentioned powder characteristics, and can be suitably used as a molding material.

In the present invention, the obtained polycarbonate powder can be provided as a molding material by adding an inorganic filler, other synthetic resins, elastomers, various additives and the like, if necessary. Various inorganic fillers can be used. Specifically, glass, carbon fiber, and other various inorganic fillers are used. First, as the glass material, for example, glass fiber, glass beads, glass flake, glass powder, and the like can be used. Here, the glass fiber used may be any of alkali-containing glass, low-alkali glass, and non-alkali glass. Its fiber length is
0.1 to 8 mm, preferably 0.3 to 6 mm, and the fiber diameter is 0.1 to 30 μm, preferably 0.5 to 25 μm.
m. The form of the glass fiber is not particularly limited, and examples thereof include various types such as roving, milled fiber, and chopped strand. These glass fibers may be used alone or in combination of two or more. These glass materials were surface-treated with a silane coupling agent such as aminosilane, epoxysilane, vinylsilane, methacrylsilane, chromium complex compound or boron compound in order to increase the affinity with the resin. It may be something. As such a glass material, for example, MA-409C manufactured by Asahi Fiber Glass Co., Ltd. (average fiber diameter 13
μm) or TA-409C (average fiber diameter 23 μm)
Etc. can be suitably used.

Next, the carbon fiber used is generally produced by sintering cellulose fiber, acrylic fiber, lignin, petroleum or coal-based pitch as a raw material. There are various types such as graphite. The fiber length of the carbon fiber is usually 0.01 to 10 mm, preferably 0.02 to 8 m
m, and the fiber diameter is 1 to 15 μm, preferably 5 to 13 μm. The form of the carbon fiber is not particularly limited, and examples thereof include various types such as roving, milled fiber, chopped strand, and strand. These carbon fibers may be used alone or in combination of two or more. The surface of these carbon fibers may be subjected to a surface treatment with an epoxy resin or a urethane resin in order to increase the affinity with the resin. As such a carbon fiber, for example, Vesfite (average fiber diameter: 7 μm) manufactured by Toho Rayon Co., Ltd. as a commercially available one can be suitably used.

Examples of other inorganic fillers include aluminum fiber, calcium carbonate, magnesium carbonate, dolomite, silica, diatomaceous earth, alumina, iron oxide, zinc oxide, magnesium oxide, calcium sulfate, magnesium sulfate, calcium sulfite, and the like. Talc, clay,
Mica, asbestos, calcium silicate, montmorillonite, bentonite, graphite, iron powder, lead powder, aluminum powder and the like can also be used.

Other synthetic resins include, for example, polyethylene, polypropylene, polystyrene, acrylonitrile-styrene (AS) resin, acrylonitrile-
Examples thereof include butadiene-styrene (ABS) resin, polymethyl methacrylate, polyester, and polyamide. Examples of the elastomer include isobutylene-isopropylene rubber, styrene-butadiene rubber, ethylene-propylene rubber, and acrylic elastomer.

Further, various additives include antioxidants such as hindered phenols, phosphites, phosphates and amines, benzotriazoles and the like.
UV absorbers such as benzophenones, light stabilizers such as hindered amines, external lubricants such as aliphatic carboxylic acid esters and paraffins, internal lubricants such as paraffin, silicone oil, polyethylene wax, flame retardants, flame retardant assistants, release agents Examples include a mold agent, an antistatic agent, a heat stabilizer, and a coloring agent. Here, examples of the coloring agent include carbon black, titanium yellow, Hansa yellow, benzidine yellow, yellow iron oxide, red iron oxide, thioindigo red, permanent red, dioxidine violet, manganese purple, phthalocyanine blue, ultramarine, phthalocyanine green, Examples include quinophthalone yellow, perinone orange, quinacridone red, quinacridone scarlet, perylene red, dioxazine violet, indanthrone blue, and titanium oxide.

[0032] In the present invention, the polycarbonate powder, optionally the inorganic filler blended with other synthetic resins, elastomers, various additives such as, kneaded, Bae
It is made into a let and is used for various moldings as a molding material. For the compounding , kneading and pelletizing , generally used methods such as a ribbon blender, a Henschel mixer,
It can be carried out using a Banbury mixer, a drum tumbler, a single screw extruder, a twin screw extruder, a kneader, a multi-screw extruder, or the like. In addition, the heating temperature at the time of kneading is usually selected in the range of 250 to 350 ° C. The supply of the polycarbonate powder to the screw may be performed by a method of gravity supply from a hopper, or may be separately performed by a pushing method using a feed screw for supply. The polycarbonate pellets thus obtained can be obtained by various known molding methods, for example,
Injection molding, blow molding, hollow molding, melt extrusion molding, melt blend molding, compression molding, calender molding, rotational molding, and the like can be applied, and are used to produce various molded products.

[0033]

EXAMPLES The present invention will be described more specifically with reference to Production Examples, Examples and Comparative Examples. Production Example 1 Polycarbonate [Taflon FN2200, manufactured by Idemitsu Petrochemical Co., Ltd.] was replaced with methylene chloride [manufactured by Hiroshima Wako Pure Chemical Industries, Ltd.,
To obtain a polymer solution having a polymer concentration of about 20% by weight. Next, heptane (special grade, manufactured by Hiroshima Wako Pure Chemical Industries, Ltd.) was added to the polymer solution in an amount corresponding to 20% by weight based on methylene chloride in the polymer solution.
On the other hand, a vertical stirring tank having an effective volume of about 8 liters (diameter of 20
cm), and equipped with a stirrer having a helical stirring blade. Into this stirring tank, 1 kg of PC powder having an average particle size of 0.5 mm, prepared by sieving polycarbonate powder (Teflon FN2200, manufactured by Idemitsu Petrochemical Co., Ltd.) in advance, was added.
g, and the above polymer solution was supplied at 6 liter / hr. At this time, the temperature of the internal powder was adjusted to 50 ° C. by heating a jacket attached to the stirring tank,
The pressure was atmospheric pressure. About 1 after supplying the polymer solution
After an hour, the powder level inside the stirring tank has risen,
The generated powder was extracted using a valve at the bottom of the tank.
About three hours after the start of powder extraction, the powder properties began to stabilize, and a sample was taken. The powder in the stirring tank continuously generates fine powder as a nucleus and the growth of the powder progresses. After a while, the powder previously charged in advance is replaced with the powder generated in the tank. I will replace my body. The powder thus obtained was dried at 120 ° C. for 12 hours under a nitrogen stream to obtain a final product. The particle size of the obtained powder is 1.3m
m, bulk density is 0.52 g / cc, and powder specific gravity is 1.02 g / cc.
cc.

Production Example 2 Polycarbonate [Taflon FN2200, manufactured by Idemitsu Petrochemical Co., Ltd.] was converted to methylene chloride [Hiroshima Wako Pure Chemical Co., Ltd.,
To obtain a polymer solution having a polymer concentration of about 23% by weight. A stirrer having a space above the stirring blade using a biaxial stirrer (kneader)
And granulated. In addition, this stirrer has a heating jacket, the bottom of the container constituting the barrel is a twin-body type (barrel width 216 mm, length 1,050 mm), and accommodates two rotating shafts (shaft diameter 60 mm). And rotate in different directions. 90 ° C. hot water was passed through the stirrer, and the polymer solution was continuously charged at a rate of 50 kg / hr. The introduction of the polymer solution was started to produce a polycarbonate powder, which was withdrawn from the outlet,
A polycarbonate powder was obtained. The obtained powder was dried under a nitrogen stream at 120 ° C. for 12 hours to obtain a comparative product.
The particle size of the obtained powder is 2.3 mm, and the bulk density is 0.62 g / c.
c, The powder specific gravity was 1.13 g / cc.

Example 1 The powder obtained in Production Example 1 was pelletized using an extruder [single screw extruder, VS40, 40φ manufactured by Tanabe Plastics Machine Co., Ltd.]. The set temperature of the barrel of the extruder is divided into four from the screw inlet,
C, 270 C, 275 C, and 275 C, and the die head is set at 270 C. Pelletization can be carried out without any problem in this state, screw rotation speed 50 rpm, die head resin pressure 55 kg / cm ² , motor current value 28 ±
It was stable at 1A.

Examples 2 to 4 Powders of various properties were prepared in the same manner as in Production Example 1 except that the powder production conditions were changed, and pelletized as in Example 1. Table 1 shows the results.

Example 5 To 5 kg of the powder obtained in Production Example 1, 50 g of titanium oxide was added as a coloring agent, and the mixture was used for 10 minutes using a mixer (Super Floter SPC-500, manufactured by Kawada Seisakusho Co., Ltd.). After kneading, the mixture was pelletized by an extruder. Next, using the obtained pellets, a molding resin temperature of 280 ° C. and a thickness of 0.05 m were used.
m to form a film. The dispersibility of the colorant was visually evaluated through the obtained film. As a result, it was found that the colorant was uniformly dispersed and mixed to form a color.

Comparative Example 1 The powder obtained in Production Example 2 was pelletized in the same manner as in Example 1. As a result, pelletization was possible, but the treatment amount was not constant, the strand was uneven, and the current value of the screw motor was unstable at 29 ± 2.6 A. Table 1 shows the results.

Comparative Example 2 Polycarbonate (Teflon FN2200, manufactured by Idemitsu Petrochemical Co., Ltd.) was sieved with a 14-28 mesh sieve to prepare a molding powder having an average particle size of about 1.1 mm. The properties of the powder were as shown in Table 1, and the powder was used in the same manner as in Comparative Example 1. Table 1 shows the results.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

As described above, the polycarbonate of the present invention
According to the method for producing molding material pellets, polycarbonate
It is easy to bite the molding material into the screw.
Suitable for various types of molding, especially extrusion processing, injection molding, etc.
Polycarbonate that can be melt molded at low temperatures
A sheet molding material pellet can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-100703 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 3/14 C08G 64/40

Claims (2)

(57) [Claims] 1. A composition having a viscosity average molecular weight of 10,000 to 50,000.
Polycarbonate powder having a mean particle size of 0.2 to 5.0 mm and a bulk density of 0.2 to 0.6 g.
/ Cc and a polycarbonate with a true specific gravity of 0.6 to 1.1 g / cc
Pelletizing Bonate powder by extruder
Characterized in that the polycarbonate molding material pellets
Production method. 2. The method according to claim 1, wherein the polycarbonate powder contains a colorant.
2. The polycarbonate molding material pellet according to claim 1,
Manufacturing method