JP2005247957A - Manufacturing process of polymer by solid phase polymerization method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems in solid phase polymerization of a polymer that maintaining the fluidity of the raw material layer becomes difficult due to the effects such as the increase in the powder pressure of the lower part of the raw material layer and the volume dilatation of the raw material layer itself, prohibiting stable continuous production, and that the unevenness of degree of polymerization due to the non-uniformity of the temperature distribution in a polymerization vessel poses a problem with respect to the stable production and the product quality; to prevent the aggromeration and fusion of the polymer in the raw material layer; to uniformize the temperature distribution in the raw material layer to resolve the unevenness of degree of polymerization of the product; and thus to provide a manufacturing process of the polymer to attain the stable production and product quality. <P>SOLUTION: In the solid phase polymerization of a polymer, the agglomeration and fusion of the polymer in the lower part of the raw material layer are reduced by controlling the powder pressure of the polymer in the lower part of the raw material layer at or below a fixed numerical value; thus, the polymer manufacturing process to attain the stable production and product quality is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a polymer by a solid phase polymerization method. More specifically, the present invention relates to a method for producing an aromatic polycarbonate or polyester in which solid phase polymerization is performed using a polymerization reaction tank having a structure capable of controlling the powder pressure in the lower part of the raw material layer in the polymerization reaction tank within a specific numerical range. .

  Various methods are generally known for producing general-purpose plastics and engineering plastics, including the “melt polymerization method” in which polymers are polymerized in a molten state. Since there is an advantage that a product can be obtained, there is an increasing tendency to adopt a “solid-phase polymerization method” in which a polymer having a low polymerization degree in a crystallized state is heated and polymerized in a solid state.

  A typical polymerization reactor used in the solid phase polymerization method is a hopper type polymerization reactor. The hopper type polymerization reaction tank is very similar in shape to a normal hopper for the purpose of storing raw materials, and it does not have a structure that will interfere with the flow of the raw material layer. Also, it does not have a stirring shaft and a stirring blade. The lower part of the polymerization reaction tank has an inverted cone shape, and the raw material is discharged from the discharge port at the apex of the inverted cone. Some have a structure for introducing an inert gas heated to the lower part of the polymerization tank for the purpose of raising the temperature of the raw material layer. As a heat treatment for the reaction polymerization tank, a method for surrounding the outer wall of the reaction polymerization tank with a general-purpose heat insulating material, a method for surrounding the outer wall of the reaction polymerization tank with a spiral pipe, or providing a jacket at the site, a liquid heating medium Various measures such as a method of circulating water vapor are often taken.

  In this way, unlike the polymerization reaction apparatus that requires a large stirring power corresponding to the high viscosity used in the melt polymerization method, the structure of the hopper type polymerization reaction tank is relatively simple, so that the polymerization reaction process is greatly improved. This makes it possible to reduce costs. Examples of other polymerization reaction tanks include fluidized bed type polymerization reaction tanks and horizontal rotary transport type polymerization reaction apparatuses. However, if the purpose is to simplify equipment and reduce costs, hopper type polymerization reaction tanks are also used. It is desirable to use it.

  However, when solid phase polymerization is carried out using a hopper type polymerization reactor, the polymerization takes a long time, and therefore the length of the polymerization reactor used in the vertical direction is generally a large value. Since the time required for the polymerization is determined by the supply / discharge capacity of the raw material and the vertical length of the polymerization reaction tank, considering that there is a limit to the lower limit of the capacity of the supply / discharge apparatus of the raw material, the numerical value is enlarged. Is inevitable. As a result, a large powder pressure is applied to the lower part of the raw material layer in the polymerization reaction tank, and the flow of the raw material layer at the site may be significantly inhibited due to this powder pressure.

  As a result of the hindering of the flow of the raw material layer, it is known that the product outlet is blocked by the formation of a consolidated layer.

  In addition, the shape of the raw material used in the solid-phase polymerization method is often in the form of pellets, flakes, or powder, but when increasing the degree of polymerization of the raw material having the shape, the temperature rise The volume expansion of the raw material layer occurs due to the influence, and the solidified layer is formed due to the influence, and the blockage occurs, and the flow of the raw material layer may be hindered.

  Furthermore, fusion may occur in the raw material layer, and the flow of the raw material layer may completely stop. When fusion occurs, not only the flow of the raw material layer is hindered, but also a large-scale maintenance of the polymerization reaction tank is required, which greatly affects the manufacturing activities in general.

  Further, the enlargement of the raw material layer height can be a factor that hinders the uniform temperature distribution in the raw material layer. When the temperature distribution is biased, the thermal history is locally different in the raw material layer, and thus the degree of polymerization is generated in the obtained product. Naturally, it is necessary to have a process of aligning the degree of polymerization or categorizing only products that have reached the desired degree of polymerization, but this not only complicates the process, but also prevents an increase in process cost. .

  Patent Document 1 (Japanese Patent Laid-Open No. 2000-248056) teaches a solid phase polymerization method using a hopper type polymerization reaction tank as a method for producing a liquid crystalline polymer. This polymerization method is a method in which the liquid crystalline polymer having a low polymerization degree obtained in the melt polymerization step is reduced to a particle size of 2 mm or more, and the polymerization degree is increased in a hopper type polymerization reactor. By specifying the viscosity, melting point, and particle size, various problems in the production of a liquid crystal polymer having a high polymerization degree comprising a melt polymerization step, a small particle reduction step, and a solid phase polymerization step are eliminated. However, no solution has been shown for the degree of polymerization caused by blockage or fusion of the product outlet due to the formation of a consolidated layer in the hopper type polymerization reactor or uneven temperature distribution.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2001-122951) teaches a method for producing an aliphatic polyester by a solid phase polymerization method. Also in this method, a fixed bed reactor (vertical reactor) is used in the solid phase polymerization step, but the above problem cannot be solved.

  On the other hand, Patent Document 3 (Japanese Patent Laid-Open No. 5-287080) describes a method for solid-phase polymerization of a granular polymer by a stationary tray method. In this method, in order to improve the heat transfer efficiency in the raw material layer, a heat transfer body is provided in the tray to eliminate unevenness in the degree of polymerization of the product. However, when assuming production on an industrial scale, the problem of polymer consolidation and fusion due to powder pressure still cannot be solved, but another problem remains in that the reaction by-products cannot be removed efficiently.

JP 2000-248056 A JP 2001-122594 A Japanese Patent Laid-Open No. 5-287080

  The difficulty of maintaining the fluidity of the raw material layer due to the increase in powder pressure at the lower part of the raw material layer and the volume expansion of the raw material layer itself as described above is a major problem that hinders stable continuous production. Is a point.

Further, the degree of polymerization caused by uneven temperature distribution in the polymerization tank also causes problems in terms of stable production of products and product quality.
Therefore, an object of the present invention relates to a method for producing a polymer by solid-phase polymerization, and prevents the polymer in the raw material layer from being consolidated or fused, and further achieves a uniform temperature distribution in the raw material layer to polymerize the product. An object of the present invention is to provide a method for producing a polymer that eliminates unevenness.

  The inventors have intensively studied to solve the above-mentioned problems, and polymer consolidation and fusion at the lower part of the raw material layer can be reduced by controlling the powder pressure of the polymer at the lower part of the raw material layer to a certain value or less. As a result, the present invention has been achieved.

  Therefore, first, the powder pressure in the lower part of the raw material layer in the polymerization reaction tank was quantified, and it was studied to control the numerical value below a certain value. For this purpose, it is desirable to actually measure the powder pressure in the lower part of the raw material layer during the polymerization reaction, but it is difficult to measure in particular because it is difficult to install a measuring device at the site of an industrial scale polymerization reaction tank. .

Therefore, the inventors decided to quantify the powder pressure using the Janssen equation, which is widely used in Japan and other Western countries, as an alternative to actual measurement. The Janssen equation is derived from a balance equation that takes into account the frictional effect of the reservoir wall of the stationary powder and shows a relatively good agreement with the actual measurement (Chemical Engineering Handbook, 6th edition, p883-p885).
The Janssen formula is represented by the following formula (1).

（式中、Ｐ_ｖは原料層の自由表面から深さｘにおける原料層水平単位断面積当たりの鉛直方向圧力（以下の記載では静置粉体圧と称す）、ρ_Ｂは原料の嵩密度、ｇは重力加速度、ｒ_ωは水圧半径、μ_ｗは槽壁摩擦係数、Ｋ_ｓはRankine定数を意味する。ｒ_ωおよびＫ_ｓは下記式（２）および（３）

(Wherein, P _v is referred to as static置粉body pressure in a vertical direction pressure (the following description of the raw material layer horizontal per unit cross-sectional area at a depth x from the free surface of the material layer), [rho _B is the bulk density of the raw material, g is the acceleration of gravity, r _ω is the hydraulic radius, μ _w is the tank wall friction coefficient, K _s is the Rankine constant, and r _ω and K _s are the following formulas (2) and (3).

で算出される値である。式中、φ_ｉは原料の内部摩擦角、Ａは重合反応槽水平断面積（原料層水平断面積と同義）、ｌ_ｃは重合反応槽内のり周長（原料層内のり周長と同義）を意味する。）

Is a value calculated by. Where φ _i is the internal friction angle of the raw material, A is the horizontal cross-sectional area of the polymerization reaction tank (synonymous with the horizontal cross-sectional area of the raw material layer), l _c is the perimeter of the polymerization reaction tank (synonymous with the perimeter of the raw material layer) means. )

However, _Pv obtained using this formula is the stationary powder pressure of the raw material layer in the polymerization reaction tank. When calculating the dynamic powder pressure when the raw material layer flows, it is necessary to multiply the value of the stationary powder pressure obtained by this formula by an appropriate coefficient.

  When handling the raw material layer in the polymerization reaction tank, it is preferable to handle the dynamic powder pressure as the actual powder pressure, but as described above, the value of the dynamic powder pressure is the value of the stationary powder pressure. Is a value obtained by multiplying by an appropriate coefficient, and any value can be used to define the value of the powder pressure. In the present invention, the stationary powder pressure is used as an index.

In the following description, the stationary powder pressure is referred to as “powder pressure”.
The “lower part of the raw material layer” means the lowest point of the straight body part of the polymerization reaction tank among the parts filled with the raw material. Therefore, the “powder pressure at the lower part of the raw material layer” means the static powder pressure at the lowest point of the cylindrical tube portion filled with the raw material.

  According to this formula, if the physical properties of the raw material used for the polymerization are known, the powder pressure strongly depends on the depth x from the free surface of the raw material layer and the polymerization reaction tank inner diameter (synonymous with the raw material layer diameter) D. I understand that.

  As a result of intensive studies on the relationship between the value of the powder pressure obtained by this formula and the flow state of the raw material layer, the inventors have found that the flow rate of the raw material layer is within a certain range. It has been found that there is no phenomenon that inhibits the above.

In addition, the inventors have the advantage of a hopper type polymerization reaction tank that enables solid-phase polymerization for a long time by increasing the vertical length of the polymerization reaction tank, and use the hopper type polymerization reaction tank. In the meantime, while ensuring the amount of product obtained in the meantime, repeated investigations to determine whether there is a way to reduce the powder pressure by reducing the value of the horizontal cross-sectional area A of the raw material layer and the peripheral circumference l _c in the raw material layer It was. As a result, it has been found that all the above-mentioned problems can be solved by using a novel polymerization reaction tank obtained by improving the multi-tube heat exchanger.

That is, the first of the present invention is a method for producing an aromatic polycarbonate or polyester in which a solid phase polymerization reaction is performed in a temperature range of a glass transition temperature (Tg) or higher and a melting point (Tm) or lower. powder pressure in the lower, i.e., _{P v} calculated by equation (1) is a method for producing a polymer characterized by a range of 150~9500N / ^{m 2} in the static置粉body pressure. A second aspect of the present invention relates to the production method of the first aspect, wherein the polymerization reaction tank to be used for the solid phase polymerization reaction is a multitubular heat exchanger type polymerization reaction tank. According to a third aspect of the present invention, the ratio (L / D) of the length (L) to the diameter (D) in the vertical direction of the raw material layer in the polymerization reaction tank is in the range of 10 to 100. The present invention relates to the production method of the first or second invention. A fourth aspect of the present invention is the production of the first or second aspect, wherein the bulk density of the raw material granular material constituting the raw material layer in the polymerization reaction tank is in the range of 290 to 930 kg / m ^3. Regarding the method. 5th of this invention is related with the manufacturing method of the said 1st or 2nd invention characterized by the angle of repose of the raw material granular material which comprises the raw material layer in the said polymerization reaction tank in the range of 15-53 degree | times. . According to a sixth aspect of the present invention, the superficial linear velocity of the inert gas introduced into the polymerization reaction tank is 0.05 m / second or more and less than the value of the flow start speed of the raw material granular material. Or it relates to the production method of the invention of 2.

According to the present invention, in a method for producing an aromatic polycarbonate or polyester in which solid phase polymerization is performed in a temperature range of a glass transition temperature (Tg) or higher and a melting point (Tm) or lower, the powder pressure at the lower part of the raw material layer in the polymerization reaction tank Is set to a static powder pressure in the range of 150 to 9500 N / m ² , there is no hindrance to the smooth flow of the raw material layer, and a stable polymer can be produced. Moreover, if a multi-tube heat exchanger type polymerization reaction tank is used as the polymerization reaction tank, the powder pressure is reduced, the raw material layer flows smoothly, the temperature distribution of the raw material layer is reduced, and the degree of polymerization is uneven. Less product polymer can be produced.

The present invention is described in detail below.
In the aromatic polycarbonate used in the present invention, the main repeating unit has the following structural formula (1).

［上記式（１）中、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４は、それぞれ独立に、水素原子、ハロゲン原子、炭素数１〜１０のアルキル基、炭素数７〜２０のアラルキル基又は炭素数６〜２０のアリール基であり、Ｗは炭素数２〜１０のアルキリデン基、炭素数１〜１５のアルキレン基、炭素数７〜２０のアリール置換アルキレン基、炭素数３〜１５のシクロアルキリデン基、炭素数３〜１５のシクロアルキレン基、酸素原子、硫黄原子、スルホキシド基、又はスルホン基である。］で表わされる。

[In said formula (1), R < ₁ >, R < ₂ >, R < ₃ > and R < ₄ > are respectively independently a hydrogen atom, a halogen atom, a C1-C10 alkyl group, a C7-C20 aralkyl group, or carbon. An aryl group having 6 to 20 carbon atoms, and W is an alkylidene group having 2 to 10 carbon atoms, an alkylene group having 1 to 15 carbon atoms, an aryl-substituted alkylene group having 7 to 20 carbon atoms, and a cycloalkylidene group having 3 to 15 carbon atoms. , A cycloalkylene group having 3 to 15 carbon atoms, an oxygen atom, a sulfur atom, a sulfoxide group, or a sulfone group. ].

  Examples of the polyester used in the present invention include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isophthalate, and the like. is not.

  Furthermore, examples of the shape of the raw material used in the present invention include powder, granules, pellets, flakes, and tablets, but are not particularly limited thereto.

The polymer raw material granular material is supplied to a polymerization reaction tank to reach a temperature range of a glass transition temperature (Tg) or higher and a melting point (Tm) or lower, and a high polymerization degree reaction is performed in a solid phase. In order to eliminate the problems of the formation of the consolidated layer and the piping clogging, the powder pressure in the lower part of the raw material layer in the polymerization reaction tank is 150 to 9,500 N / m ² , preferably 1000 to 9000 N / m ² , more preferably in the range of 2000 to 8500 N / m ² .

  Further, in the present invention, a multi-tube heat exchanger type polymerization reaction tank obtained by improving a multi-tube heat exchanger as a polymerization reaction tank in order to eliminate polymerization degree unevenness caused by uneven heat distribution in the polymerization reaction tank. use.

  The multi-tube heat exchanger here is a kind of partition wall type heat exchanger, and a plurality of heat transfer tubes are provided inside the fuselage tube, a high-temperature fluid is added to either the fuselage tube or the heat transfer tube, and Heat exchange is performed by circulating a low-temperature fluid on one side. Commonly used multi-tube heat exchangers consist of three parts, a fixed head, trunk, and occipital area. There are several types for each part, and these three parts can be combined as appropriate. It is. (The basic structure is described in, for example, the Chemical Engineering Handbook Revised Sixth Edition p388)

  However, it is impossible to use a multi-tube heat exchanger as it is as a polymerization reaction tank. When continuous production of the polymer is assumed, it is necessary to continuously charge the raw material into the polymerization reaction tank and continuously discharge it. In addition, it is necessary to supply and discharge a heated inert gas used as a main heating medium. Therefore, in order to make the multi-tube heat exchanger function as a polymerization reaction tank, it is necessary to improve the equipment.

  The multi-tube heat exchanger type polymerization reaction tank of the present invention will be described below with reference to FIG. 1, but is not limited to FIG.

  First, since the back of the head (symbol 9 in FIG. 1) is a part related to product discharge (symbol 11 in FIG. 1), a generally used cylindrical tube or end plate is not used, but an inverted conical tube is used. Further, since it is necessary to continuously introduce an inert gas from the portion, an inert gas inlet (reference numeral 12 in FIG. 1) is provided on the side of the tube.

  Similarly, since the fixed head (reference numeral 3 in FIG. 1) is a portion (reference numeral 1 in FIG. 1) related to the raw material charging, a conical tube is used. Since it is necessary to continuously discharge the inert gas from the portion, an inert gas discharge port (reference numeral 15 in FIG. 1) is provided on the side of the tube.

  As for the body (reference numeral 5 in FIG. 1), the liquid heating medium supply port (reference numeral 13 in FIG. 1), the outlet (reference numeral 14 in FIG. 1), the jacket (reference numeral 7 in FIG. 1), etc. It is not necessary to improve the structure, but a dispersion plate having a structure for dispersing the charged raw material and the introduced inert gas into a plurality of heat transfer tubes (reference numeral 6 in FIG. 1) (in FIG. 1) 4 and 8) can be provided above and below the trunk.

  For the input of raw materials and the discharge of products (reference numerals 2 and 10 in FIG. 1), a general-purpose granular material transport device can be used. For example, a rotary feeder, a table feeder, a bale feeder, a belt feeder, a chain feeder, a screw feeder, a vibratory feeder and the like can be used, but are not limited thereto.

When the multi-tubular heat exchanger type polymerization reaction tank is used, the hopper type polymerization reaction tank has the advantage of being capable of solid phase polymerization for a long time and the hopper type polymerization reaction tank is used. In addition, it is possible to reduce the values of the raw material layer horizontal cross-sectional area A and the raw material circumferential length l _c while substantially securing the amount of product obtained, and the powder pressure at the lower part of the raw material layer can be greatly reduced.

  The raw material layer horizontal cross-sectional area A depends on the polymerization reaction tank inner diameter (synonymous with the raw material layer diameter) D, and reducing the raw material layer horizontal cross-sectional area A is synonymous with reducing the raw material layer diameter D. is there. Further, the depth x from the free surface of the raw material layer is synonymous with the vertical length L of the raw material layer when considered as the distance from the uppermost point of the raw material layer to the lowest point.

  If the raw material layer diameter D is reduced, the amount of product obtained is naturally reduced. In order to avoid this, measures to improve the supply and discharge capacity of raw materials and products or to increase the vertical length L of the raw material layer are effective, but considering the limit of the supply and discharge capacity of the granular material transport device In this case, it is a good idea to increase the vertical length L of the raw material layer.

  However, there is a limit to reducing the raw material layer cross-sectional area A by reducing the raw material layer diameter D. When the raw material layer cross-sectional area A becomes extremely small, the vertical length L of the raw material layer becomes extremely large, aiming at maintaining good fluidity of the raw material layer, simplifying equipment, and reducing equipment costs. Contrary to the spirit of the present invention. Therefore, in this invention, the suitable range of the ratio (L / D) of the length L of the raw material layer in the polymerization reaction tank and the raw material layer diameter D (L / D) is in the range of 10 to 100, preferably 10 to 50, Preferably it is the range of 10-30.

  Raw material granules as a factor that directly affects the amount of product in conducting a polymerization reaction in a multi-tube heat exchanger type polymerization reaction tank in which a plurality of cylindrical tubes within the range of L / D, which is considered to be suitable, are arranged Bulk density.

When the raw material layer vertical particle length D and the raw material layer diameter D are fixed uniformly, when the raw material granular material having a large bulk density is used, the weight of the raw material layer itself increases, The powder pressure increases. Conversely, when using raw material granules with low bulk density, although the powder pressure at the lower part of the raw material layer is reduced, the amount of product obtained is reduced, and the scale of the polymerization reaction tank is enlarged to avoid this Turn into. Therefore, the suitable range of the bulk density of the raw material granular material in this invention is 290-930 kg / m < ³ >, Preferably it is 400-900 kg / m < ³ >, More preferably, it is the range of 500-800 kg / m < ³ >.

  In addition, the angle of repose of the raw material granules has a great influence on the powder pressure in the lower part of the raw material layer. When a raw material granular material having a large angle of repose is used, the coefficient of friction between the inner wall of the cylindrical tube that is in contact with the raw material granular material and the raw material granular material increases, which in turn increases the powder pressure below the raw material layer. Although it is necessary to make the angle of repose of the raw material granular material as small as possible, it is necessary to further refine the raw material granular material, and formation of a consolidated layer and blockage of the piping related to the fine powder generated in the process May encourage problems. Therefore, the suitable range of the angle of repose of the raw material granular material in the present invention is 15 to 53 degrees, preferably 25 to 45 degrees.

  Also in the present invention, the inert gas is used as a main heating medium for raising the temperature of the raw material. In order to obtain a product with a high degree of polymerization in a state free from unevenness of the degree of polymerization, it is necessary to distribute a large amount of a high-temperature inert gas close to the melting point (Tm).

  Since the amount varies depending on the scale of the polymerization reaction tank, it is not possible to uniformly define the preferred range, but the superficial linear velocity obtained by dividing the flow rate value by the value of the polymerization reaction tank cross-sectional area A The value can be roughly specified.

  When the superficial linear velocity of the inert gas is extremely low, the temperature distribution in the raw material layer becomes large, and thus the degree of polymerization of the resulting product becomes large. In addition, since the reaction by-product cannot be removed efficiently, the problem of the formation of the consolidated layer and the blockage of the piping is promoted. Conversely, when the superficial line velocity is extremely high, the temperature distribution in the raw material layer, the degree of polymerization of the product, and the problem of formation of a consolidated layer and blockage of piping are eliminated, but the raw material powder is inactive. There is a possibility that the material layer will not be maintained due to floating in the gas. In addition, an increase in the superficial linear velocity may cause a differential pressure between the polymerization reaction tank and the transportation process after the product is discharged, and the product discharge amount per unit time may not be maintained. Therefore, in the present invention, the preferred range of the superficial linear velocity of the inert gas introduced into the polymerization reaction tank depends on the properties of the raw material such as the particle size and bulk density of the raw material, but preferably 0.05 or more per second. It is less than the value of the flow start speed of the raw material, more preferably in the range of 0.1 to 1 m.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.
The intrinsic viscosity [η], glass transition temperature (Tg), melting point (Tm), crystallinity, and viscosity average molecular weight (Mv) of the aromatic polycarbonate were determined by the following methods.

に代入することで算出した。尚、マーク−ホーウインク定数Ｋおよびαの値は、シュネル氏の値（Ｋ＝１．２３×１０^−４、α＝０．８３）を採用した。 (1) Intrinsic viscosity [η]
Measurements were made in an Ubbelohde viscosity tube at 20 ° C. in dichloromethane.
(2) Glass transition temperature (Tg) and melting point (Tm)
The glass transition temperature (Tg) and the melting point (Tm) were determined by a Perkin Elmer DSC7 at a heating rate of 10 ° C./min. Moreover, the enthalpy (ΔHm) of crystal melting was calculated from the area of the portion corresponding to crystal melting.
(3) Crystallinity Obtained by DSC measurement with a ΔHm of 100% crystalline aromatic polycarbonate of 109.8 J / g (J. Polym. Sci .: B: Polym. Phys., 25, pp1511-1517, 1979). The ΔHm value was divided by 109.8, and the obtained value was calculated as a percentage.
(4) Viscosity average molecular weight (Mv)
The intrinsic viscosity [η] determined by the above (1) is expressed by the following equation called the Mark-Hou ink viscosity equation:

It was calculated by substituting for. Note that Schnell's values (K = 1.23 × 10 ⁻⁴ , α = 0.83) were adopted as the Mark-Houwink constants K and α.

[Reference Example 1: Synthesis Example of Amorphous Low Molecular Weight Aromatic Polycarbonate]
228 parts by weight of 2,2-bis (4-hydroxyphenyl) propane, 223 parts by weight of diphenyl carbonate, 0.009 part by weight of tetramethylammonium hydroxide, and 0.00014 part by weight of bisphenol A disodium salt were stirred, reduced in pressure, And a reactor equipped with each device such as a distillation column and stirred for 1 hour in a nitrogen atmosphere at 180 ° C. to dissolve all the raw materials. Subsequently, the amorphous low-molecular-weight aromatic polycarbonate was subjected to a polymerization reaction by gradually increasing the temperature and reducing the pressure until the final temperature reached 220 ° C. and the final pressure reached 20 mmHg. The obtained amorphous low molecular weight aromatic polycarbonate had an intrinsic viscosity [η] of 0.17, a viscosity average molecular weight (Mv) of 6078, and a glass transition temperature (Tg) of 120 ° C.

[Reference Example 2: Crystallization operation example of amorphous low molecular weight aromatic polycarbonate]
The amorphous low molecular weight aromatic polycarbonate obtained in Reference Example 1 was pulverized and classified, and one having a particle size in the range of 2 to 3 mm was collected. The collected pulverized product was immersed in a mixed solution at 100 ° C. composed of phenol / water = 2/8 (weight ratio) for 30 minutes, and the amorphous low molecular weight aromatic polycarbonate was crystallized. After immersion, the mixed solution was filtered off and dried at 100 ° C. for 16 hours. The obtained crystalline low molecular weight aromatic polycarbonate has an intrinsic viscosity [η] of 0.17, a melting point (Tm) of 221 ° C., a crystallinity of 24.3%, a bulk density of 632 kg / m ³ , and an angle of repose of 34 degrees. Met.

[Example 1]
Using a multi-tubular heat exchanger type polymerization reactor as shown in FIG. 1, increasing the degree of polymerization of a crystalline low molecular weight aromatic polycarbonate using the crystalline low molecular weight aromatic polycarbonate obtained in the above Reference Example as a raw material The reaction was carried out. The outer diameter of the barrel (reference numeral 5 in FIG. 1) of the multitubular heat exchanger type polymerization reactor is 216.3 mm, the inner diameter is 208.3 mm, the height is 4000 mm, and the heat transfer tube (reference numeral in FIG. 1). The outer diameter of 6) was 60.5 mm, the inner diameter was 52.7 mm, the height was the same as that of the trunk, and eight were provided in the trunk. Further, the back of the head (reference numeral 9 in FIG. 1) is an inverted conical pipe, and an inert gas inlet (reference numeral 12 in FIG. 1) is provided on the side of the pipe so that the inert gas can be continuously introduced. . Similarly, the fixed head (reference numeral 3 in FIG. 1) is a conical tube, and an inert gas discharge port (reference numeral 15 in FIG. 1) is provided on the side of the pipe so that the inert gas can be continuously discharged. It was. Further, a dispersion plate (reference numerals 4 and 8 in FIG. 1) was provided above and below the trunk so that the introduced raw material and the introduced inert gas could be uniformly dispersed in a plurality of heat transfer tubes. A rotary feeder was used for charging the raw material (reference numeral 2 in FIG. 1), and a screw feeder was used for discharging the product (reference numeral 10 in FIG. 1). First, a liquid heating medium is circulated inside the body so that the temperature in the heat transfer tube is constant at 220 ° C., and then nitrogen gas heated to 220 ° C. is introduced into the body from the inert gas inlet described above. did. After confirming that the temperature in the heat transfer tube was constant, 28 kg of raw material was charged from the raw material supply port (reference numeral 1 in FIG. 1). The charged raw material is evenly distributed to the eight heat transfer tubes by the dispersion plate described above, and the ratio (L / D) of the vertical length L of the raw material layer to the raw material layer diameter D is 48.2, When the powder pressure in the lower part of the raw material layer in each heat transfer tube was calculated, the static powder pressure was 427.9 N / m ³ . The amount of inert gas introduced was adjusted so that the superficial linear velocity of the inert gas in each heat transfer tube was 0.15 m, and continuous feed of raw materials and continuous discharge of products were started. The discharge amount and the input amount were the same. Product discharge was confirmed from the product outlet (symbol 11 in FIG. 1), but the product discharged here is not a product that has received a sufficient heat history, but a product with a low degree of polymerization. The start of operation was defined as 10 hours after the start of continuous input and continuous discharge of the product. After the start of operation, the obtained product was collected every 2 hours, and the intrinsic viscosity [η], the viscosity average molecular weight (Mv), and the melting point (Tm) were measured. The operation was continued for 10 hours after the start of operation. The results are shown in Table-1.

[Example 2]
The same operation as in Example 1 was carried out except that the outer diameter of the heat transfer tube was 48.6 mm, the inner diameter was 41.2 mm, the number of heat transfer tubes provided in the body portion was 13, and the amount of raw material to be charged was 22 kg. . The charged raw material is evenly distributed to the 13 heat transfer tubes by the dispersion plate described above, and the ratio (L / D) of the vertical length L of the raw material layer to the raw material layer diameter D is 48.7, When the powder pressure in the lower part of the raw material layer in each heat transfer tube was calculated, it was 334.5 N / m ³ as a static powder pressure. Table 2 shows the measurement results of intrinsic viscosity [η], viscosity average molecular weight (Mv), and melting point (Tm) of the obtained product.

[Example 3]
The same operation as in Example 1 was performed, except that the outer diameter of the heat transfer tube was 89.1 mm, the inner diameter was 83.1 mm, the number of heat transfer tubes provided in the body portion was three, and the amount of raw material to be charged was 21 kg. . The charged raw material is evenly distributed to the three heat transfer tubes by the dispersion plate described above, and the ratio (L / D) of the vertical length L of the raw material layer to the raw material layer diameter D is 24.6, When the powder pressure in the lower part of the raw material layer in each heat transfer tube was calculated, it was 674.8 N / m ³ as a static powder pressure. Table 3 shows the measurement results of intrinsic viscosity [η], viscosity average molecular weight (Mv), and melting point (Tm) of the obtained product.

[Example 4]
The crystalline low-molecular-weight aromatic polycarbonate raw material obtained in the above-mentioned reference example was further pulverized, and one having a particle size in the range of 0.5 to 1 mm was collected. The intrinsic viscosity [η], melting point (Tm), and crystallinity of the raw materials were the same, but the bulk density was 744 kg / m ³ and the angle of repose was 24 degrees. The same operation as in Example 1 was performed except that the pulverized material was used as a raw material and the amount thereof was 33 kg. The charged raw material is evenly distributed to the eight heat transfer tubes by the dispersion plate described above, and the ratio (L / D) of the vertical length L of the raw material layer to the raw material layer diameter D is 48.2, When the powder pressure in the lower part of the raw material layer in each heat transfer tube was calculated, it was 511.6 N / m ³ as a static powder pressure. Table 4 shows the measurement results of intrinsic viscosity [η], viscosity average molecular weight (Mv), and melting point (Tm) of the obtained product.

[Example 5]
The same operation as in Example 4 was performed except that the superficial linear velocity of the inert gas in each heat transfer tube was set to 0.05 m. Table 5 shows the measurement results of intrinsic viscosity [η], viscosity average molecular weight (Mv), and melting point (Tm) of the obtained product.

[Comparative Example 1]
Except removing the upper and lower dispersion plates, the outer diameter of the heat transfer tube is 165.2 mm, the inner diameter is 158.4 mm, the number of heat transfer tubes provided in the barrel is one, and the amount of raw material to be charged is 15 kg The same operation as in Example 1 was performed. The ratio (L / D) between the vertical length L of the raw material layer and the raw material layer diameter D was 7.6, and the powder pressure at the lower part of the raw material layer in each heat transfer tube was calculated. It was 1282.3 N / m ³ . Table 6 shows the measurement results of intrinsic viscosity [η], viscosity average molecular weight (Mv), and melting point (Tm) of the obtained product.

[Comparative Example 2]
Except for removing the dispersion plates on the top and bottom of the body, changing the outer diameter of the heat transfer tube to 27.2 mm, the inner diameter of 21.4 mm, the number of heat transfer tubes provided in the body to 52, and the amount of raw material to be charged to 33 kg The same operation as in Example 1 was performed. The ratio (L / D) between the vertical length L of the raw material layer and the raw material layer diameter D was 130.5, and the powder pressure at the lower part of the raw material layer in each heat transfer tube was calculated. 173.8 N / m ³ . Immediately after the start of operation, the product started to be discharged, but the product was not confirmed at the product outlet and the operation was stopped. When the multitubular heat exchanger type polymerization reaction tank was disassembled and the inside of the heat transfer tube was observed, the raw material formed a consolidated layer at the center of the heat transfer tube.

It is a vertical direction cross-sectional schematic diagram of an example of the multitubular heat exchanger type | mold polymerization reaction tank which can be used by this invention.

Explanation of symbols

1. 1. Raw material polymer supply port 2. Rotary granular material transport device 3. Conical fixed head 4. Raw material polymer dispersion plate 5. Torso part Raw material polymer distribution pipe (heat transfer pipe)
7). Jacket 8 8. Inert gas dispersion plate Inverted conical occipital region 10. Rotating powder and granular material transport device11. Product outlet 12. Inert gas supply port 13. Liquid heating medium supply port 14. Liquid heating medium outlet 15. Inert gas outlet

Claims (6)

In a method for producing an aromatic polycarbonate or polyester in which a solid-phase polymerization reaction is performed in a temperature range of a glass transition temperature (Tg) or higher and a melting point (Tm) or lower, the powder pressure at the lower part of the raw material layer in the polymerization reaction tank is left stationary. A method for producing a polymer, wherein the powder pressure is in the range of 150 to 9500 N / m ² .   The method according to claim 1, wherein the polymerization reaction tank is a multitubular heat exchanger type polymerization reaction tank.   The method according to claim 1 or 2, wherein the ratio (L / D) of the length (L) to the diameter (D) in the vertical direction of the raw material layer in the polymerization reaction tank is in the range of 10 to 100. . The method according to claim 1 or 2, wherein the bulk density of the raw material granular material constituting the raw material layer is in the range of 290 to 930 kg / m ³ .   The method according to claim 1 or 2, wherein the angle of repose of the raw material granular material constituting the raw material layer is in the range of 15 to 53 degrees.   The method according to claim 1 or 2, wherein a superficial linear velocity of the inert gas introduced into the polymerization reaction tank is 0.05 m / second or more and less than a value of a flow start velocity of the raw material granular material.

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