JPS60116412A - Manufacture of polycarbonate resin granular body - Google Patents

Abstract

PURPOSE:To increase bulk density, and to dry the titled granular body easily by evaporating methylene chloride at 1.1-50atm. from the hot water dispersion of a polycarbonate type methylene chloride solution. CONSTITUTION:Polymer concentration in the methylene chloride solution of polycarbonate resin is brought to 3-35wt%. The solution is dispersed to hot water, and methylene chloride is evaporated at pressure of 1.1-50atm. in a granulating device, thus manufacturing polycarbonate resin granules. An agitator normally having an agitator, a methylene chloride solution introducing pipe for a resin and an evaporated methylene chloride drawing-out pipe, to which a valve for adjusting pressure, may be used as the granulating device. A temperature where the vapor pressure of methylene chloride reaches to said pressure or higher may be used as the temperature of hot water. The volume ratio of the methylene chloride solution of the resin to hot water is brought to 1:0.1-4, preferably, approximately 1:0.2-3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polycarbonate resin granules that have a large bulk density and are easy to dry, from a methylene chloride solution of a polycarbonate resin.

As a method for obtaining polycarbonate resin granules from a methylene chloride solution of a polycarbonate resin, a method is known in which a methylene chloride solution of a polycarbonate resin is added to hot water or hot water, and the methylene chloride is evaporated in the warm water or hot water. (For example, Tokusho QO-3! 3.3,
Tokuko Sho I Otsu-37q21/-). However, when these methods are used, the resulting polycarbonate resin granules have a bulk density of O, D? / CrA, and cannot be said to be fully satisfactory. Moreover, the polycarbonate resin granules after being separated from water have a high water content and require a large drying load.

As a result of extensive research into the manufacturing method of polycarbonate resin granules, the present inventors have found that when manufacturing polycarbonate resin granules as described above under a specific pressure, they easily have a large bulk density and can be easily separated from water. The present invention was completed based on the knowledge that it is possible to obtain polycarbonate resin granules with extremely low water content after drying.

That is, the purpose of the present invention is to produce polycarbonate resin granules that have great industrial value.
This objective is achieved by dispersing a solution of polycarbonate resin in methylene chloride in hot water and evaporating the methylene chloride under a pressure of /,/-30 atmospheres to form polycarbonate resin granules.

The present invention will be explained in detail below.

A divalent group represented by the general formula or -SO□-, R is a hydrogen atom,
They are monovalent hydrocarbon groups or halogen atoms, and may be of the same type or different types. R' represents a divalent hydrocarbon group, and the aromatic nucleus may have a halogen atom or a heptavalent hydrocarbon group. ) and a bischloroformate of phosgene or a dihydroxydiaryl compound are reacted by interfacial polymerization or solution polymerization in the presence of methylene chloride and an acid binder such as caustic alkali or pyridine. A polycarbonate resin solution obtained by washing and removing impurities from the resulting reaction mixture using an aqueous washing solution is mentioned.

Specific examples of dihydroxydiaryl compounds represented by the general formula include bis(lI-hydroxyphenyl)
Methane, /, /-bis(couhydroxyphenyl)ethane, λ, 2-bis(couhydroxyphenyl)furopane, λ, 2-bis(lI-hydroxyphenyl)butane,
λ1,2-bis(+-hydroxyphenyl)octane,
Bis(terhydroxyphenyl)phenylmethane, core 2-bis(+-hydroxy-3-methylphenyl)propane, /, /-bis(ll-hydroxy-3-th, 37
'f-ruphenyl)propane;1,2-bis(q-hydroxy-3-bromophenyl)propane;2,1-bis(terhydroxy-3,s-dibromophenyl)propane; bis(hydroxyaryl)alkanes such as -,7,5-dichlorophenyl)propane, t,/-bis(lI-hydroxyphenyl)cyclopentane, and /,/-bis(terhydroxyphenyl)cyclohexane; ) cycloalkanes, q.

q′-dihydroxydiphenyl ether,! ', I
dihydroxy diaryl ethers such as I'-dihydroxy-3,3'-dimethyldiphenyl ether;
+,+'-dihydroxydiphenyl sulfide, dihydroxydiaryl sulfide such as ri'-dihydroxy-3,3'-dimethyldiphenyl sulfide
q, y'-dihydroxydiphenyl sulfoxide, +
, +'-dihydroxydiaryl sulfoxides such as 3,3'-dimethyldiphenyl sulfoxide, f,+'-dihydroxydiphenyl sulfone,
Examples include dihydroxydiarylsulfones such as 4(,9'-dihydroxy-3,3'-dimethyldiphenylsulfone).

These can be used alone or in a mixture of two or more,
In addition to these, hydroquinone, resorcinol, <z, +'
-Dihydroxy compounds such as dihydroxydiphenyl, halides of dicarboxylic acids such as terephthalol chloride and iso7thaloyl chloride, diamines such as piperazine and diviperazyl, etc. may be used in combination.

Methylene chloride used as a solvent for polymerization reaction is /θwt%
It may also contain other solvents such as chloroform, carbon tetrachloride, /, -1-dichloroethane, /, /, l-)lychloroethane, tetrachloroethane, chlorobenzene, etc. to a lesser extent.

Such a mixed solvent is not inconvenient in the production of the polycarbonate resin granules of the present invention, and therefore can be used directly in the method of the present invention following the polymerization reaction without separating methylene chloride from other solvents.

The polymer concentration of the methylene chloride solution of the polycarbonate resin targeted in the present invention is 3 to 33% by weight, preferably! -21% by weight.

In the present invention, a methylene chloride solution of the polycarbonate resin is dispersed in warm water, and the methylene chloride is evaporated under pressure to obtain polycarbonate resin particles. The granulation equipment used here can be any equipment that can heat, pressurize, and stir, but it usually includes a stirrer, a resin methylene chloride solution inlet pipe, and an evaporated methylene chloride outlet pipe equipped with a pressure adjustment valve. A stirring tank with a

To disperse the methylene chloride solution of the resin in hot water, the hot water may be charged in a granulating device and the methylene chloride solution of the resin may be added to this while stirring, or the two may be mixed and dispersed in a separate device in advance. It may also be introduced into a granulation device.

The pressure in the granulation device is /, / ~ SO atmospheric pressure, preferably /,
/ to -0 atmospheres, more preferably /, λ to 10 atmospheres. If this pressure is too low, the effects of the present invention cannot be expected. On the other hand, a high temperature is not disadvantageous in terms of the high density and moisture content of the granules obtained, but it is not advantageous in terms of equipment, operation, heat source costs, etc. This pressure can be set, for example, by applying the hot water temperature to a pressure regulating valve installed in the evaporation methylene chloride outlet pipe, as long as the vapor pressure of methylene chloride is at least the above pressure, taking into account the desired evaporation rate of methylene chloride. Just choose.

The volume ratio when dispersing a methylene chloride solution of a resin in hot water varies depending on the type of polycarbonate resin, molecular weight, resin concentration in the methylene chloride solution, etc., but usually the methylene chloride solution:water volume ratio is /2. 〇, /～months, preferably h, about a～3.

In addition, the polycarbonate resin granules produced in the granulator form a water slurry, and the amount of polycarbonate resin granules in this water slurry is preferably J-3θ weight % based on the water slurry from the viewpoint of stirring and handling. is S
A range of −+0% by weight is preferable.

In this way, when producing polycarbonate resin granules by evaporating methylene chloride, it is possible to obtain polycarbonate resin granules that have a large bulk density and an extremely low water content after separation from water, which is extremely advantageous in terms of drying and handling. be.

The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

In addition, in the examples, "%" indicates "1 weight ratio".

In addition, the particle size is expressed as sieve weight cumulative SO% (Dp-sθ), and the particle size distribution is 1975/θ month, is day, R=/θO
It is shown as the value of n in exp (-bDpn).

Examples / and Comparative Examples / Water was poured into a 2Ot (inner diameter 2Acrn) jacketed stirring tank equipped with a polymer solution inlet pipe, an evaporated methylene chloride outlet pipe with a pressure adjustment valve, and a bladed propeller with a blade diameter of A. /! ; tf: After charging and stirring, the reduced viscosity (ηθp/C) of this water was 0. ! ; 73% methylene chloride solution of 2eLt/f polycarbonate resin 20 if:/
While introducing at a rate of Ot/hr, methylene chloride was evaporated under conditions of pressure/J atm and water temperature sgc to produce polycarbonate resin granules.

The resin granules obtained by centrifuging the water slurry containing the obtained resin granules had a water content of 5.3%.

When this resin granule was vacuum dried for 6 hours, its bulk density was 0.!; lIt/ml, particle size (Dp-taO) was /, particle size distribution (n value) was j
, it was A.

For comparison, the pressure adjustment valve was opened and the pressure was set to /atmosphere, and the other operations were performed in the same manner as in Example /.
The moisture content of the obtained resin granules was 0% Ir, the bulk density of the dry product was 0.2 gt/ml, and the particle size (Dp-5
0) was /, ll-m, and the particle size distribution (n value) was 2.9.

Example λ The same procedure as in Example 1 was carried out except that the pressure was 29 g atm and the water temperature was 75 C. The moisture content of the resin granules obtained was y, g%, and the bulk of the dry product was The density is OAr 7 t/ml, the particle size (Dp-so) is /,
3. tWrjn, particle size distribution (n value) was 3, g.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - 7 others 11- -Rinichi

Claims (1)

[Claims] (1) Polycarbonate resin granules are produced by dispersing a polycarbonate resin methylene chloride solution in hot water and evaporating the methylene chloride under a pressure of /, / to SO atmospheric pressure to produce polycarbonate resin granules. Manufacturing method.