KR860001059B1 - Process for anionic polymerization - Google Patents

Abstract

Anionic polymerization monomer, e.g., alkenyl aromatic monomer having formula Ar-CR1 = CH2; where R1 = H or methyl; and Ar = C1-6 alkyl- substituted 1-3 aromatic ring compd., styrene, or p-vinyl toluene, is polylmerized with organic metal anionic initializer, e.g., butyl lithium in a continuous stirred tank reactor or closed-loop reactor. The reactor comprises flow rate control systems of raw material and measuring systems of molecular weight of polymer effluent. These generate signals for manipulation of the initializer feeding rate to maintain the uniform molecular weight of the product.

Description

Anion polymerization method

1 shows an apparatus suitable for an embodiment of the method of the invention.

2 and 3 show sampling devices for measuring the molecular weight of polymers.

The present invention relates to a novel method and apparatus for controlling anionic polymerization in a continuous stirred tank reactor.

By continuous stirred tank reactor is meant all reactors in which material is added into the reactor continuously at about the same rate and then removed from the reactor and the composition and temperature for the contents of the reactor are kept almost uniform. Thus, the continuous stirred tank reactor may have a model of a conventional cylindrical or spherical stirred tank, or may be a loop type for rapidly recycling the material in the loop.

Typically the polymerization is carried out using a plug flow reactor in which the composition at the inlet end is very different from that at the outlet end and can maintain a temperature gradient inside the reactor. There is no such phenomenon in a continuous stirring tank reactor.

In general, the polymer is preferably prepared using an anionic initiator in a continuous stirring tank reactor, in which the monomer and anionic initiator are optionally added continuously with a diluent and the resulting product is removed to remove the polymer in the next step. It can preferably be used for recovery in pellet form.

A highly desirable property of commercial polymers is the uniformity of composition and molecular weight. Mixing various batches to provide uniformity is expensive.

Molecular weight variations between polymer batches can cause many manufacturing difficulties. Usually, a gel is formed during polymerization, especially with alkenyl aromatic polymers. In general, such gels are readily found when extruding polymers into strands because of properties such as agglomeration of strands, where agglomerates or sluboid formations are generally proportional to the gel content. Such gel-containing polymers are generally unsuitable for extrusion or injection molding because the final product exhibits surface irregularities and may be different from the model of the mold.

Many studies have been done to control anionic polymerization using colorimetric devices as described in US Pat. Nos. 3,290,116, 3,468,972 and 3,743,629. In practice, the sensitivity of the colorimeter may change over time. In addition, impurities in monomers and diluents change over time as well as an effective amount of initiator.

Accordingly, what is needed is an improved method and apparatus that can control anionic polymerization that provides a product that contains little gel and has a nearly constant average molecular weight.

These advantages include a device for controlling the flow rate of monomer and initiator feedstock into the reactor and the reactor effluent, with the content of the reactor being nearly uniform, the addition of polymerized components continuously, followed by the continuous flow of the reaction mixture from the reactor at about the same rate. Yalkenyl aromatics capable of anionic polymerization in a continuous stirred tank reactor, further characterized by a device for measuring a molecular weight of the polymer in the reactor to generate a signal that controls the rate of initiator addition into the reactor to provide a polymer of approximately constant molecular weight. Achieved by a method of polymerizing monomers with an organic country anionic initiator.

A particularly preferred embodiment of the present invention provides a first order signal that is varied by the molecular weight of the polymer in the effluent from the reactor, the first order signal altering the rate of polymerization initiator added to the reactor to change the molecular weight of the polymer. Remain nearly constant; Measuring the molecular weight of the polymer to generate a second signal; Using this secondary signal to correct for deviations or errors in the primary signal generator device to maintain a nearly uniform molecular weight of the polymer in the reactor effluent.

The present invention also provides a device for producing an anionic polymerized ilkenyl aromatic polymer, the device comprising a monomer feeder; A monomer flow rate control device connected to an outlet of the monomer supply device; Anion polymerization initiator feeder; An initiator flow rate control device connected to an outlet of the initiator supply device; Continuous stirred tank reactor with inlet and outlet, the inlet of this reactor has a cooperative function of monomer flow control device and initiator flow control device to receive the appropriate amount of material from these two devices. Outlet pipe with cooperative function; A primary signaling device that changes as the molecular weight of the polymer in the effluent from the continuous stirred tank reactor changes, the primary signal controlling the molecular weight of the polymer to be produced by controlling the initiator flow rate; An apparatus for measuring a molecular weight of the polymer and generating a secondary signal indicative of the molecular weight of the polymer; It consists of a device that receives a secondary signal and provides a primary signal that modulates the device to provide a polymer of approximately constant molecular weight.

The term ilkenyl aromatic monomer means an anionic polymerizable monomer composition containing at least 50% by weight of monomer having the following general formula:

In the above formula,

R is hydrogen or methyl,

Ar is an aromatic ring structure in which all alkyl groups have 1 to 3 aromatic rings with or without alkyl substituents containing 1 to 6 carbon atoms. All remaining monomers of the above-mentioned alkenyl aromatic monomers are monomer materials capable of anionic copolymerization with alkenyl and aromatic monomers.

Representative alkenyl aromatic monomers that may be used alone or in admixture include styrene, α-methylstyrene, vinyltoluene (all isomers, p-toluene are preferred), ethyl styrene, propyl styrene, tertiary butyl styrene, octyl styrene , Vinylnaphthalene, vinylbiphenyl, vinylanthracene and mixtures thereof.

Anionic polymerization is well known in the art.

Representative systems thereof are illustrated in US Pat. Nos. 3,030,345, 3,954,894, 4,196,153, 4,200,713 and 4,205,016.

In general, the polymerization is preferably carried out in the presence of a solvent which is inert to the polymer material formed. Representative solvents include benzene, toluene, ethylbenzene and ethyltoluene alone or in small amounts; Alkyl compounds (e.g., cyclohexane) and mixtures thereof.

In carrying out the present invention, it is preferable to maintain the composition and temperature of the reaction mixture uniformly in the polymerization vessel. The temperature of the reaction mixture is preferably maintained at ± 30 ° C, preferably ± 1.5 ° C throughout. In order to achieve the desired temperature and composition uniformity in recirculation coil reactions as described in US Pat. No. 3,035,033 to Schweitzer et al., The capacity of the material to be recycled in the coil is added to the coil and at least 15 times the capacity of the material to be discharged from the coil. Preferably 25 times. In the case of stirred tank reactors, the temperature and composition of the reaction mixture should be uniform at all locations in the reactor except in the immediate vicinity of the monomer feed point. In the case where the stirrer for supplying the monomer in the radial direction inward through the tank side at the bottom is a tank having a diameter of 1.0 m and a height of 2.0 m with an axial direction, the temperature and composition of the reaction mixture are 0.1 m or more from the feed point. It should be nearly constant at all locations within. In general, the more mixing, the more uniform the product obtained and the lower the gel formation rate.

In the polymerization reaction carried out in accordance with the invention, the conversion of monomers to polymers is usually above 99% by weight and the solids concentration is almost constant due to the nature of the continuous stirred tank reactor and the rapidity of the polymerization. Every 1% solids variation in the reaction mixture to produce polystyrene with a molecular weight of about 300,000 will change the molecular weight to about 4,000, which causes a large amplitude in the primary signaling device.

The primary signal generator may be of any kind as long as it is a sensitizer that generates a signal indicating the molecular weight of the polymer. In general, in anionic polymerization, the polymerization mixture produces colored anions. For example, when polymerizing styrene using an organolithium initiator, deep red changes appear somewhat proportional to the number of end groups present, thus indicating polymer molecular weight. Viscometers are also useful for analyzing the number of endgroups.

The secondary signaling device is preferably a device capable of comparing the outflow of the primary signaling device by actually measuring the molecular weight of the product in the reaction mixture to provide a substantially standard value. As the secondary signal generator, various kinds of devices may be used, for example, a viscometer, a light scattering system, or the like. However, a preferred embodiment is to use the gel permeation chromatograph method which measures the known molecular weight of the standard polymer and the polymer molecular weight in the reaction mixture alternately in order to obtain maximum reliability.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 shows a device suitable for practicing the method of the present invention, which device is generally indicated by reference numeral 10. In this apparatus 10, the supply tank 11 provided with the inflow pipe 12, the inflow pipe 13, and the outflow pipe 14 (where the pump 15 is provided here) is comprised as a mutually cooperative function. Tube 14 is connected to water inlet tube 17. Tubes 14 and 17 flow out to tube 18 with a heat exchanger 19 installed inside the tube. Tube 18 flows into cracking column 21. The effluent of the cranking column 21 flows out into the tube 23 having the heat exchanger 24 installed inside the tube, the decanter 25, the water outlet tube 26 and the organic material receiving tank 17. Organics from tank 27 proceed through tube 28 to distillation column 29. Distillation column 29 has top outlet lines 31 and 32. The outlet pipe 31 is provided with a heat exchanger 33 therein. Tube 31 is connected to tube 32 and flows out. The distillation column 29 has an outlet tube 35 and a recycle tube 36 equipped with a heat exchanger 37 therein. Tube 35 exits a second distillation column 38 having upper outlet tubes 39 and 41 as well as a lower circulation system similar to column 29. Tube 39 is provided with a capacitor 42 therein. Tube 41 is equipped with liquid storage tanks 43 and 44 therein. Tanks 43 and 44 are connected in series. Tube 41 ends in a continuous stirred tank reactor 46. Reactor 46 has an inlet 47 and an outlet 48. Reactor 46 has a closed loop model with pump 46a to agitate or circulate the liquid therein. The anionic polymerization initiator supply tank 51 is connected to the tube 51 by the tube 52. Inside the pipe 52, a flow control device or a variable speed pump 53 is provided. The outlet 48 of the continuous stirred tank reactor 46 has a cooperative function with the tube 55. Inside the tube 55, there is a device 56 which provides a signal which is varied by the molecular weight of the polymer contained in the material flowing through the line 55. Also included in line 55 is a device 57, such as a color detector, that provides a primary signal that changes as the molecular weight of the substance flowing out of line 55 changes. Controller 58 has a cooperative function with devices 56, 57 and pump 53. Tube 55 away from outlet 48 flows into terminal agitator 61. In addition, the terminal agitation reactor 61 is connected to an inlet pipe 62 and an outlet pipe 63 equipped with a pressure control valve 64 therein. Tube 63 flows into nonvolatile device 65. The nonvolatile device 65 has a lower outlet tube 66 and an upper outlet tube 67. Within line 67 is a quality indicator 68, such as an infrared spectrophotometer.

2 shows a sampling device for measuring the molecular weight of polymer flowing out of polymerizer 46a into line 55a. As shown in FIG. 2, tube 71 is optionally connected to line 55a. Tube 71 advantageously flows out of mixing chamber 72 which is small in volume and equipped with a stirrer 73 inside thereof. The stirrer 73 is advantageously operated with a magnet. The mixing chamber 72 is connected to the nitrogen or other inert gas supply pipe 74 and the discharge pipe 75. Tubes 74 and 75 are each equipped with a valve therein. Mixing chamber 72 flows out through tube 77 to gel permeation chromatography 81. Tube 77 is provided with a valve therein. The standard polymer feeder 78 is connected to a valve tube 79 connected to gel permeation chromatography 81. Line 77 from chamber 72 is also connected to the gel permeation chromatograph. As shown in FIG. 2, a suitable solvent such as tetrahydrofuran is pumped through gel permeation chromatography under a pressure of 515 KPa (60 psig). Material from polymerizer 46a passes through four-way valve 82 via line 55a.

In FIG. 3, the four-way valve 82 is rearranged so that some of the material exiting through line 55a passes through the mixing chamber 72 through the tube 71 and passes through the gel permeation chromatograph 81.

The method and apparatus of the present invention can be used to provide a variety of polymers and copolymers, but FIG. 1 shows an arrangement that is particularly suitable for preparing polystyrene from ethylbenzene. Ethylbenzene was fed to tube 12 and stored in tank 11 and then passed through tube 14 via line 14 and pump 15 where it was mixed with water and heated in heat exchanger 19 to obtain a mixture of ethylbenzene and steam cracking column. Pass it to 21. The effluent from the cracking device is sent via line 23 to a heat exchanger 24 which cools the effluent. After cooling, the effluent from the cracking column passes through the decanter 25 and the water flows out of the tube 26. The crude styrene passes through the crude styrene tank 27 from the decanter. From tank 27 the crude styrene is conveyed via tube 28 to distillation column 29. Distillation column 29 serves to remove low boiling point impurities such as benzene, toluene and residual water. The subfraction from the first distillation column 29 passes through line 35 and part is recycled and heated via line 36 and heat exchanger 37. Tube 35 flows a fraction consisting primarily of ethylbenzene and styrene to distillation column 38. A high boiling fraction consisting mainly of tar and cymen flows out from the bottom of distillation column 38. The top fraction from the second distillation column is sent to reactor 46 via tubes 43 and 44 in tube 41. The upper fraction is a mixture of almost equal parts of ethylbenzene and styrene. The effluent from the continuous stirred tank reactor 46 is mixed with the anion polymerization initiator from tube 52 and pump 53 and then flows through tube 55 and detectors 56 and 57. Tube 55 exits to another continuous stirred tank reactor 61 where the polymer is deactivated when the polymer is mixed with ethanol. Effluent from reactor 61 is sent to non-volatile unit 66 via tube 63 and pressure control valve 64, where ethylbenzene is removed and molten polystyrene is removed from tube 65 through tube 66.

Molecular weight detector 56 provides a signal to computer 58, which indicates the weight average molecular weight of the polymer. Color detector 57 also provides a signal to computer 58, which then adjusts the set point of color detector 57 to obtain a polymer of nearly constant molecular weight. Computer 58 also provides a signal to pump 53, thus providing a desired amount of anion initiator to maintain the desired weight average molecular weight. In practical applications, continuous detection of molecular weight is usually unnecessary. In practical terms, the molecular weight should be detected at least every 8 hours, and the setpoint of the color detector should be adjusted accordingly. Molecular weight and set point control is preferably at two hour intervals. As shown in FIGS. 2 and 3, the molecular weight arrangement 56a intermittently samples the resulting vapor to dilute a certain amount of steam (dilute in chamber 72) and pass the material through gel permeation chromatography 81. . Standards are used to precisely control the molecular weight of the product and to obtain accurate results from gel permeation chromatography. In other words, polymers of known molecular weight and distribution are passed through a gel permeation chromatograph for calibration. Gel permeation chromatography is a preferred method for measuring molecular weight. However, other methods may also be used, such as melt runoff, solution viscosity, light dispersion and vapor phase osmosis.

In practicing the present invention, it is preferred that the residence time of the material in the reactor is 1 to 3 hours. If the residence time is less than 1 hour, it is difficult to control the molecular weight. If the residence time is more than 3 hours, the process is uneconomical. The polymerization temperature is very preferably maintained at 80 ° to 140 ° C. When the temperature is 80 ° C. or lower, the amount of initiator used is excessive, and when the temperature is 140 ° C. or higher, the conversion from monomer to polymer is reduced. The weight percent polymer to solvent in the reactor should be from 30 to 80 weight percent. When the solids content of the reactor is less than 30% by weight, excess solvent must be removed to recover the polymer.In the case where the solids content of the reactor is more than 80% by weight, the viscosity of the reaction mixture can be most practically controlled by the processing equipment. It is higher than the present viscosity. Generally preferred solvents are alkylaromatic materials. The most readily available solvent is ethylbenzene. However, xylene and toluene may also be used.

The main advantage of the process of the present invention is that a small amount of lithium initiator can be used to produce polymers with very low yellowness indices. To achieve the desired results, the oxygen content of the feed stream sent to the reactor should be maintained at less than 1 part by weight (ppm) based on the weight of the total feed stream. Above 1 ppm adversely affects the color of the recovered polymer. Likewise, if water is present, it should be present in an amount less than 10 ppm, and active hydrogen, emulsifiers (e.g. acetylene) and oxygen-containing organic impurities should be kept below 60 ppm, because these materials are also present in the color of the polymer. This is because it has an adverse effect. The recovered polymer should contain 20 ppm or less of lithium, since the presence of lithium adversely affects the color of the present invention. Preferably, the conversion from monomer to polymer is at least 99% by weight.

The present invention is explained in more detail by the following examples.

Example 1

The apparatus of this embodiment is generally used according to FIGS. 1 to 3. The grading device consists of three main parts: a preheating part of about 1 length filled with a ceramic Beryl saddle, a 0.5m cranking part with an hourly space velocity of 2,14 reciprocating hours and a shell 105 It consists of a part filled with a commercially available ferric oxide containing cranking catalyst. The cracking temperature is 625 ° C. and the pressure is 136 KPa (5 psig). In the third part of the cracking device the temperature is reduced to 300 ° C. The first two cracking sections were heated to a capacity of about 2500 watts using a ceramic heater and the ratio of water to ethylbenzene was 0.9. The condenser corresponding to condenser 24 is cooled water. Between the condenser 24 and the decanter separator 26 is a gaseous liquid separator 25 which is a flat vessel of about 490 cm 3 capacity. The crude styrene from the gas phase liquid separator is fed into the first distillation column from the tank corresponding to tank 27. The first distillation column is 5.0 cm in diameter and is used to supply 40 times the theoretical excess and to fill and to remove light fractions from the crude mixture. Benzene, toluene and water are the primary substances removed. The bottom portion from column 29 is fed to a second distillation column. The first distillation column operates under a pressure of 17.3 KPa and has a bottom temperature of 90 ° C. and a reflux ratio of about 5: 1. The second distillation column is 10 cm in diameter and is filled to have 40 equivalents of theory. The second distillation column is operated at a water temperature pressure of 14.6 KPamm and a lower temperature of about 85 ° C. The reflux ratio is 6: 1. The upper composition removed from the second distillation column is a mixture of styrene and ethylbenzene with a ratio of about 1: 1. Submaterials are mainly tar and para-cymene. Both columns have a residence time of about 2 hours. Storage containers corresponding to tanks 43 and 44 have a residence time of about 24 hours. Both tanks are maintained under a nitrogen stream with a pressure of 240 KPa (20 psig). Impurities other than styrene and ethylbenzene are maintained at about 100 parts by weight or less per weight. Material from tank 44 proceeds to a continuous stirred tank reactor 46 using a double head 0.63 cm Milton-Roy piston pump. The reactor is a 2.5 cm diameter recycle coil connected in the forward direction inside the 316 stainless steel tube. The tube is coated and heated with hot water. The contents of the stainless steel tube reactor are circulated and operated at approximately 2200 rpm by the northern gear pump number 4448. The internal volume of the reactor is 1867 cm 3. The gear pump is located near the inlet of ethylene and the initiator and downstream thereof to quickly mix the viscous polymeric material and the initiator recycled into the reactor into the feed mixer. The pressure in the reactor is maintained at 450 KPa (50 psig) by manipulating a pressure regulating valve such as valve 64 in FIG. The polymerization initiator used is standard-butyllithium taken as a 15% solution in heptane and prior to use it is diluted with toluene to give a standard-butyllithium concentration of about 0.5 to 1% per weight. The pump used to transfer standard-butyllithium is a Milton-Roy Piston pump driven by a variable speed electric motor controlled by a computer.

The computer program used is:

f0: * Z + 1 Z

f1: * sfg0; spc2; p rt "Valves off ot"; cfg1; cfg3; s fg8

f2: * sfg0; spc2; p rt Color Control 1 off at "; cfg 2

f3: * sfg0; spc2; p rt "Mw control off at; cfg3

f4: * sfg0; spc10; prt "PF Cntrl of f at"

f5: * X; sfg5

f7: * VX; sfg6

f11: * V3 * 12 = 360 and I> V [2 0 +130: V3 * 12-2I

f13: * sfg0; spc2; prt "Valves on at"; sfg1; Wait "B $

f14: * sfg0; spc2; prt "color control cl on at"; sfg2

f15: * sfg0; spc2; prt "Mw control cn at; sfg3

f16: * sfg0; sfg10; prt "PF Cntrl o r at"

0: "anion polymerization control program W / GPC; Patent Case";

1: "start # 's2-16, hardware and software"

2: dimB $ [20], A $ [14], D [150], T [150], V [35], M [7], W [7], F [7], C $ [20], C [3]

3: "Initializes variables, loads sp.function keys";

4: -3 I: 3} r: 2} z: 1} R: sfg7: trk 1: 1dk 1: gsb "time"

5: "required variable, clear 723 bus"

6: gsb "assign": rds (723)} J: on err "error"

7: "fmt # 1 for relays, # 2 for A / D; # 3for D / A; # 4 for display";

8: "fmt 1;" 0140TG "., Fz4,0," T ", z

9: fmt 2, c, z; fmt 3, c, f4.0, c, a; eir 7

10: "Clear D / A Card"

11: wrt 723, 2 "0120TD0000TD2000TD4000TD6000T"

12: "# 's 14-16 Clock start";

13: "1 for int / detection, 2, U3 coefficient / detection for int / valve";

14: wrt 9, "A, U1 =, U1 = 01, U2 = U2 = 02, U3 + 13, Ur = 14"

15: wrt 9, "U1P3000 / U2P5000"

16: Oni 9, "clock"; eir 9; wrt 9, "U2G"

17: "#" s 19-44, main display loop ";

18: "display device for sampling device";

19: Z = 1 and flg1: dsp B $, D, V 3-I / 12, K

20: Z = 1 and not flg1: dsp "Sampling device is off"

21: flg3 and not flg2: "Mw control" C $

23: not flg2 and not flg3: "color control" C $

23: flg2 and not flg3: "control off" C $

24: "display for control mode and parameters";

25: When Z = 2: dsp C $, H, V [5], r32 / 5.11

26: dsp "Term, trans. =", P for Z = 3

27: "display for GPC data";

28: flg1, Z = 4 and A / 2-int (A / 2) = 0: fxd 0; dsp "Last Mw =", r21

29: lg1, Z = 4 and A / 2-int (A / 2) # 0: dsp "Last MWD =", r22

30: Z = 4 and not flg1; dsp "GPC is off",

31: "MWD control display device"

32: Flg5 is set by SK key and indicates change of operation variable ";

33: flg5: for gsb: gsb "variable"

34: "flg9 is set by peak-termination and allows GPC calculation":

35: flg9: gto "GPCcalc"

36: "flg0 is set by the SK key, indicating the change of variables and giving time":

37: flg0: wrt9, "R": red9, A $: prtA $ ‥ cll "Allocation: spc2: cfg0

38: "shut down of valves";

39: r50 = 1: wrt9, “U1HU3HU3C”; wrt723.1,0; 0} K} D; -5} I

When 40: r = 50 = 1: wrt723.3, "0140TD", 2000, "T"; wrt723.3 "0140TD, 6000," T "; 0} r50

41: "end of loop";

42: for Z6: 2} Z

43: fxd2: gto 19

44: "GPCcalc": cfg9: gsb "time"

45: prt "GPC calculation: dsp" GPC calculation in progress "

46: "starting peak (S) found by weight average";

47: V [1]} r5

48: forJ-V [9] +15 to V [9] -1 by-1

49: When J = V [9] and 3 ^* V [1] <r5: prt "Peak error not found" gto "Peak error";

50: for J = V [9]: 1.1r5; r5; 15 + V9} J; gto48

51: D [J] + 2 ^* D [J-1] + D [J-2] <= D [J-1] + 2 ^* D [J-2] + D [J-3] + r5 gto53

52: next J

53: J-1} S; V [2]} r6

54: "peak end (S) found by mean of weight";

55: for J-V [10] -15 to V [10] +1

56: When I = V [10] and 3 ^* V [2] <r6: prt "Peak not found" gto "Peak error"

57: When J = V [10]: 1.1r6} r6; V [10] -15} J; gto55

58: D] J] +2 ^* D [J + 1] + D [J + 2] <= D [J + 1] +2 ^* D [J + 2] D [J + 3] + r6: gto 60

59: next J

60: J + 1} F

61: "Calculate the intercept (B) and slope (M) of the baseline"

62: (D [F] -D (S1) / (T [F1-T [S])} M

63: D [S] -M ^* T [S]} B

64: "subtract the peak baseline off and check the negative value";

65: for J = S to F

66: D [J] -M ^* T [J] -B} W

67: J <S + 5, W <= 0, J # S; G to 62 for J} S

68: J> F5, W <0, J # F; G to 62 for J} F

69: next J

70: ForJ = S to F; D [J] -M ^* T [J] -B} D [J]

71: next J

72: "Peak Size Check and Peak Data Print

73: Maximum value D [*])> 18: "Peak too high: gto" Peak error "

74: max (D [*] <12: prt "peak too small": gto "peak error"

75: prt "peak-height" max D [*]

76: fxd 0: prt "peak-start", S: prt "peak-end", F

77: gsb "total"

78: "Calculate and control pass and Mw for std.";

78: K = 0; 0} r9: gto] 08

80: "calculated, Mn, Mw, MWD;

81: r4 ^* r7 / r5} r20; r4 ^* r6 / r73} r21; r4 ^* r11 / r6} r12; r21 / r20} r22

82: wrt723.3, "0140TD", dto (r21-VI301 '/ (V [31] -V [30]) ^* 500) +2000, "T"

83: wrt723.3, "0 40TD", dto (r2-V32) / (V33-V33-V33) ^* 500) +6000, "T"

84: "If Mw is not controlled, pass";

85: if not flg3: g to 93

86: "sample deviation and inspection of the first sample";

87: When abs (r21-r35) <[16] and r35 # 0: prt "Mw deviation" gto 93

88: "calculate transfer change";

89: V [18] ^* (r21-V [4]) / 1000 / r33

90: "transfer new%, calculate setpoint";

91: V [5] -r 33 / V [5]; r21} r35

92: "round-off Mn, Mw data";

93: r 20 ^* , 001} r 20; r21 ^* 001} r21; r12 ^* .001} r12

94: r21-int (r20)> = .5: r20 + 1r20

95: r21-int (r21)> = .5: r12 + 1r21

96: r12-int (r12)> = .5: r12 +} r12

97: int (r 20) ^* 1000} r 20; int (r21) ^* 1000} r21; int (r12) ^* 1000} r12

98: "printer output of Mw data";

99: fxd 0; prt "Mn =", r20; prt "Mw =", r21; prt "Mz =", r12

100: fxd 2; prt "Mw / Mn =", r22; prt "Mx / Mw =", r12 / r21

101; "Mw control, prt for new setpoint";

102: flg3; prt new setpoint ", V [5]

103: When recording mode on, prt:

104: flg10: gsb "report"

105: "end of calculation, reversal with dsp loop";

106: O} D} T; = gto 19

107: "old money or checks";

108: when abs (r5 ^* 6 / r72-V [11]) <. 001: gto 118

109: "#s 119-127 calib.calc., Successive iteration"

110: r5 ^* r6 / r72-V [11]> = 0: gto 11

111: 1.05r8} r8: gsb "sum"

112: gto 110

113: when abs (r5 ^* r6 / r72-V [11]) <. 0001; gto 118

114: r5 ^* r6 / r72-V [11] <0; r8} r9; r10} r8: .5 (r8-r9) + r9} r8; gto 116

115: r 8} r 10; , 5 ^* (r8-r9) + r9} r8

116: gsb "sum"

117: gto 113

118: V [12] ^* r7 / r6} r4; fxd3; prt "scale factor"

119: "printer output of scale";

120: fxd0; prt "C1 =", r4, fxd3; prt "C2 =", r8; 0D} T; gto19

121: "sum loop for Mw calculation";

122: “sum”; 0} r5} r6} r7} r11

123: for J = S to F

124: exp (r8 ^* T [J])} E

125: r5 + D [J] * E} / r5; r6 + D [J] / E} r6; r7 + D [J]} r7; r11 + D [J] / E2} r11

126: next J: ret

127: "routine for resetting valve loop error";

128: "peak error"; For K # 0: gto19

129: O} K} D} T; -8} I; wrt723. 1,24; gto19

130: "Allow offline input of Mw data";

131: "offline"

132: "% transfer set point adjustment";

133: V [5] -V [18] ^* (V [19] -V [4] / 10000} V [5]

134: prt "New (01) s.p. =", V [5}; ret

135: The prt valve is a relay write routine for GPC cycle time <30 minutes ";

136: "I is a 5sec counter and K is a sample counter";

137: "valve": I + 1} I; V [3] ^* 12; 0} I

138: K = 0 and I = 0: wrt 723,1,40: "injection standard"} B $

139: K> 0 and I-4-V [28]: wrt723,1,14: "injection sample" B $

140: K = 0 and I = 4: wrt723,1,200: "Running Standard" B $

141: K> 0 and I = 4: wrt723,1,224

142: When K = V [15] and I = 5: "final sample" B $

143: K> 0 and I = 5: wrt 723.1,20

144: K <V [15] and IV [3] ^* 12-118; wrt 723.1,1; Sample Coil "B $

145: K <V [15] and I = V [3] ^* 12-116; wrt723.1,100 ‥ "Stirring"} B $

146: When I = V [17] +4: wrt9, "U3GU1G", 0} L

147: When I = V [20] +4: wrt9, "U1HU3HU3C" stg9

148: when K <V [15] and I = V [3] ^* 12-6 wrt723.1,0; "Stir stop"} B $

149: K <V [15] and I = V [3] ^* 12-2: wrt723.1,4

150: I = V [3] ^* 12-1; K + 1}: K = V [15] +1; 0} K

151: ret

152: "Long valve is 30 minutes GPC cycle"

153: "Std / samp / wait / std / samp / wait ..... order";

154: "long valve"; I + 1} I; J = V [3] ^* 12; -2} if I

155: when I = -2: wrt723.1,40; "Injection standard" B $; 0} K

156: when I = 3: wrt723.1,200; "Running Standard" B $

157: when I = 4: wrt723.1,1; "Sample Coil" B $

158: When I = 5: wrt723.1,0

159: When I = 6: wrt723.1,1

160: when I = 7: wrt723.1,100; "Running Standard" B $

161: When I = V [17] +3: wrt9, "U3GU1G", 0} L

162: When I = V [20] +3: wrt9, "U1HU3HU3C" stg9

163: for I = 120: wrt723.1,0; "Sample Completed" B $

164 : When I = 122: wrt723.1,4

165: for I = 127-V [28]: wrt723.1,14; " ^* Inject Samp."} B $

166: for I = 127: wrt723.1,1224

167 for I = 128: wrt723.1,20; "Running Standard" B $

168: when I = V [17] +127: wrt9, “U3GU1G”, wrt723.1,4000; 0} L

169: for I = V [20] +127: wrt9, “U1HU3HU3C”; wrt723.1,0; 1} K; stg9

170: When I = V [20] +128: " ^* Waitin"} B $

171: ret

172: "Determine interrupt and branch clock" (3 or 5 sec)

173: "So, also include multicolor, term color, red for IR";

174: "clock": wrt9, "T"; rdb (9) {Q; eir9

175: bit (O, Q): cll 'detector': gto189

176: not flg1 or flg7: gto179

177: bit (1, Q) and V [3} ^* 12 <360: gsb "valve"

178: bit (1, Q) and V [3} ^* 12> = 360: gsb “long valve”

179: A + 1} A; If .A = V [27]: OA

180: for A # O: gto189

181: C [2]} C [3]; C [1]} C [2]; C} C [1]

182: wrt723.2, "0160TA13TO260TAX"; red723, C; otdc / 40} C

183: "This is an average of 4 or more multicolor readings for recording";

184: (C + C [1] + C [2] + C [3] / 4} H

185: wrt723.2, "0160TA12TO260TAX"; red723, P; otdp / 40} P

186: "Branch when color control is on";

187: not flg2: gsb "control"

188: "clear IB bus and multiple programmers";

189: when rds (723) = 64; eir7

190: iret

191: "The detector reads the GPC detector, running clock and memory data";

192: "detector"; L + 1} L; eir9

193: wrt723.2, "0160TA11TO260TAX"

194: red 723, D; wrt9, "U3V '; red9, T; T / 60000T

195: otdD} D; D ^* .005} D; D} D [L]; T [L]

196: ret

197: "Supply display for changing operator variables";

198: "variable": for flg5: gsb "time": cfg5

199: X = 1: dsp "Is the peak-initiation sensitivity factor?"

200: When X = 2: dsp "Is the peak-termination sensitivity factor?"

201: When X = 3: dsp "Are GPC cycle time in minutes?"

202: for X = 4: dsp "Mw setpoint?"

203: When X = 5: dsp "% Transmission set point?"

204: When X = 6: dsp "Are control gain?"

205: When X = 7: dsp "Is it a reset constant?"

206: X = 9: dsp "Maximum peak elution time?"

207: When X = 10: dsp "Maximum peak elution time?"

208: X = 12: dsp "Is the standard molecular weight?"

209: When X = 12: dsp "Is the standard molecular weight?"

210: When X = 13: dsp "Minimum catalyst pump rate (%)?"

211: When X = 14: dsp "Maximum catalyst pump speed (%)?"

212: for X = 15: dsp "#of samples between std?"

213: When X = 16: dsp "Mw error deviation?"

214: for X = 17: dsp "Is it clock-clockwise?"

215: For X = 18: dsp "Are you the% transfer adjustment constant?"

216: When X = 19: dsp "Insert-off-line Mw data!"

217: When X = 20: dsp "Is it a clock-stop counter?"

218: X = 21: dsp "Is the rate of new catalyst pump (%)?"

219: When X = 27: dsp "A read cycle (5sec. Inc.)?"

220: In case of X = 30: dsp "Are you in charge (5sec. Inc.)?

221: X = 30: dsp "Mw Molytek 0?"

222: For X = 31: dsp "Is Mw Molytek up?"

223 for X = 32: dsp "Is Mz Molytek 0?"

224 for X = 33: dsp "Mz Molytek is max?"

225: X = 0: ret

226: if flg6 is not: jmp0

227: cll 'print'; ret

228: "Control of NBL Pump from% Transmission Deviation";

229: "control"

230: HV [5]} r 30; r30 ^* V [6] + r31} r32

231: r32 <V [13] ^* 5.11: V [13] ^* 5.11} r32

232: r42> 5.11 ^* V [14]: V [14] ^* 5.11} r32

233 for flg4: gto "pump"

234: r31 + r30 ^* V} r31

235: r31 <V [14] ^* 5.11: V [14] ^* 5.11} r31

236: r31> V [13] ^* 5.11: V [13] ^* 5.11} r31

237: "pump": wrt723.3, "0140TD", dtor32, "T"

238: ret

239: "printing time routine for various changes";

240: "time": wrt9, "R"; red 9, A $, spc 2; prtA $; ret

241: "Output of recording data after GTC calculation";

242: "record": fxd2

243: prt "pump speed", r32 / 5.11

244: prt "% trans. =", H; spc2; ret

245: "Check to see if all required variables are assigned";

246: "every time the control mode change is executed";

247: "assign"

248 for flg2: gto255

249: V [5] = 0; 5} X: gsb "variable"

250: V [6] = 0; 6} X: gsb "variable"

251: V [7] = 0; 7} X: gsb "variable"

252: V [13] = 0; 13} X: gsb "variable"

253: V [14] = 0; 14} X: gsb "variable"

254: V [27] = 0; 27} X: gsb "variable"

255: not flg1; gto272

256: V [3] = 0; For 3} X; gsb "variable"

257: V [1] = 0; For 1} X; gsb "variable"

258: V [2] = 0; 2} X; gsb "variable"

259: V [9] = 0; For 9} X; gsb "variable"

260: V [10] = 0; For 10} X; gsb "variable"

261: V [11] = 0; 11} X; gsb "variable"

262: V [12 [= 0; 12} X; gsb "variable"

263: V [15] = 0; For 15} X; gsb "variable"

264: V [17] = 0; For 17} X; gsb "variable"

265: V [20] = 0; 20} X; gsb "variable"

266: V [28] = 0; 28} X; gsb "variable"

267: V [30] = 0; 30} X; gsb "variable"

268: V [31] = 0; 31} X; gsb "variable"

269: V [32] = 0; 32} X; gsb "variable"

270: V [33] = 0; 33} X; gsb "variable"

271: bfg7

272: not flg3; gto 276

273: V [4] = 0; 4} X; gsb "variable"

274: V [16] = 0; For 16 $ X; gsb "variable"

275: V [18] = 0; At 18 $ X; gsb "variable"

276: ret

277: "Supply print copies of operator changes";

278: "print"; cfg6fxd0

279: when X = 1; fxd3; prt "Upslope factor =", V [1]

280: when X = 2; fxd3; prt "Downslope fact =", V [2]

281: when X = 3; prt "GPC cycle time =", V [3]

282: when X = 3 and V [3] ^* 12J = 360; sfg8; prt "override to longvalves'; beep

283: when X = 4; prt "Mw setpoint =", V [4]

284: when X = 5; fxd3; prt "for transfer set point =", V [5]

285: when X = 6; fxd3; prt "Controller gain =", V [6]

286: when X = 7; fxd3; prt "reset constant =", V [7]

287: when X = 9; prt min peak time = ", V = [9]

288: when X = 10; prt "standard MWD =", V [10]

289: when X = 11; fxd2; prt "MWD of std. =", V [11]

290: when X = 12; prt "standard MW =", V12; V [12] rl r2

291: when X = 13; prt "Minimum catalyst speed =", V [13]

292: when X = 14; prt "Maximum catalyst rate =", V [14]

293: for X = 15; prt "sample cycle =", V [15]

294: X = 16; prt "Mw deviation limit =", V [16]

295: when X = 17; prt "Clock start =", V [17]

296: case of X = 18; prt "transmission control constant =", V [18]

297: when X = 19; prt "off-tine Mw =", V [19]; gsb "offline"

298: when X = 20; prt "clock stop =", V] 20]

299: when X = 21; fxd2; prt "pump speed", V [21]; V [21] * 5.11 r31

300: when X = 27; prt "Read cycle =", V [27]

301: when X = 28; prt "master time =", V [28]

302: X = 30: prt "Mw Molytekzero =", V [30]

303: For X = 31: prt "Mw Molytek max =", V [31]

304: For X = 32: prt "Mz Molytek zero =", V [32]

305 for X = 33: prt "mx Molytek max =", V [33]

306: OX; spc2; ret

307: "error", wrt723.1,4000; wait15000; wrt723.1, 0; stp ^* 1106

In the computer program, items 2 to 16 start all variables and delete the mode card. Real-time clocks are set up and started for use. Items 19 to 43 control the 9825's display, which the operator can change by pressing a specific function key (SFK) f1 on the computer. Calculate the molecular weight of the polymer by reading items 44-126 detector. This segment operates when all readings have been collected and are under control of the valve subroutine. Items 88 through 91 are those that actually change the colorimeter-initiator addition rate control loop. Items 98 to 100 record molecular weight information on paper tape. Items 130-134 input off-line of molecular weight. That is, the operator can input Mw information from another external source and modify the colorimeter-initiator addition rate control loop. Items 135-171 include subroutine "valve" and "long valve". The valve controls the GPC sampling valve when the GPC cycle is less than 30 minutes. This control is performed by writing to the relay card and turning off a specific relay. This feeds the power to the ASCO * solenoid valve via a relay so that Whit continues to open or close the "whitey ^* ball valve." The standard frequency (how many samples approximate the standard value) can vary with variable V [15] In addition, the GPC cycle (V [13]) can change with every 5 seconds increment. Another variable included in this subroutine controls the injection time V [28] when the computer reads it in a GPC detector for dissolution of injection samples V [17] and V [20]. (1) Used for GPC cycle times of 30 minutes or more, (2) Standard samples, standard samples …… allow only sample cycles of items 172 to 190. Subroutine " Clock "is two important Firstly, it determines that it should be read from the calculator if it is a real-time clock signal at stop, and secondly, it reads the input signal from a colorimeter or GPC detector. Items 228 through 238 are colorimetric control subroutines that calculate the continuously varying initiator addition conditions based on the anion concentration in the reactor effluent. This is done by converting the amount of powder before supply to the motor running the initiator-added pump The computer produces a 0-10V signal to the PARAJUST ^* motor controller, and then outputs the power output to the motor. Specific function key tapes are written copies of items stored on a specific function key on the computer. That can control the type of control, variable valves, displays, etc. These items are recorded on the cassette tape, thereby continue the entry # Computer memory in (trk1, 1dk1).

Note that not all of the items in the computer program are used.

Example 2

A 1: 1 weight ratio mixture of styrene and ethylbenzene was fed to the heat exchanger at 55 ° C. and discharged through a spray nozzle in a receiver with an internal pressure of 2.6 KPa to purify the feed stream and remove oxygen and most of the residual water. The feed from the receiver passes through a bed of molecular sieve sold under the trade name Linde3A, where the bed has a ratio of two to two diameters in length at the speed of five parts of unwarranted vapor by sieve weight. The feedstock obtained contained less than 1 ppm oxygen, 3 ppm water, 5 ppm benzaldehyde, 5 ppm styrene oxide, 5 ppm acetophenone and about 40 ppm phenylacetylene, and styrene and ethylbenzene contained about 1: 1. have.

The purified styrene-ethylbenzene feed is fed to a polymerizer using a double head 0.6 cm Milton-Roy pump. The polymerizer is a 2 l ordinary cylindrical reactor (commercially available under the Parran trade name) equipped with a vacuum auger stirrer with a length and diameter of the cylinder slightly smaller than the interior of the auger. The lands are arranged spirally on the outside of the cylinder in which the cylinders are arranged to occur by the rotation of the vacuum cylinder and the lands are also slightly smaller than the internal volume of the reactor. Such reactors are described in US Pat. No. 4,239,863. Hot water under pressure is used to heat the reactor to 95 ° C. The purified feed stream and initiator are injected into the reactor at a constant rate to provide a residence time of 2 hours. The initiator is normal-butyllithium supplied at a rate that provides about 60 ppm. The pressure in the reactor is maintained at 450 KPa (50 psig) using a pressure control valve at the outlet. The steam from the reactor is fed to an end coil having a diameter of 2.5 cm and an internal volume of about 467 cm 3 connected squarely inside the 316 stainless steel tube. The material is recycled at about 200 rpm in the end coil using northern gear pump stock number 4448. A 1 wt% ethanol solution in ethylbenzene is fed to the end coil at twice the rate of feeding standard-butyllithium into the polymerization vessel. The effluent from the end coils is then fed under pressure to a non-volatile device equipped with a flat plate heater and a spiral extractor as described in US Pat. No. 3,014,702. The outside of the heater is maintained at a pressure of 4.67 KPa and the reaction mixture is heated to a temperature of about 240 ° C. to provide a polymer containing 0.8 wt% volatiles. The molecular weight of the polymer obtained after 24 hours is maintained at 210,000 ± 5,000. The color of the product has a good yellowness index of 0.007.

Example 3

About 1: weight ratio mixture of styrene and ethylbenzene was purified as in Example 1 except in special cases, 42 wt% styrene, 58 wt% ethylbenzene, 1 ppm or less oxygen, 5 ppm water, 14 ppm acetophenone, Provided is a purified feed containing 5 ppm benzaldehyde, 5 ppm styrene, oxide and about 34 ppm phenylacetylene. The polymerization vessel used consists of a 19831 tank with a condenser mounted vertically on top of it. The condenser has a cooling surface of 14.7 cm 3. The vessel and the condenser are supported on the extender cell, the outflow of which is used to control the capacity of the reaction mixture in the vessel. Vacuum devices are used to provide reduced pressure in the vessel. Steam removal is used to maintain the desired polymerization temperature. Variable speed pumps are installed at the bottom of the vessel to remove polymer therefrom, and the speed of the pump generally varies to maintain the weight of the polymerization vessel. The polymerization vessel is suitable for agitators driven by hydraulic pressure rotating at about 100 rpm. Aggregates from the condenser are recycled to the feed stream. The polymerization vessel is operated under the following conditions: 680 kg of reactor; Feed rate 386 kg / hr; Retention time 1 to 3/4 hours: Reaction mixture temperature 100 ° C: Reactor pressure 31.5 KPa: Standard-butyllithium 80 ppm based on the total amount of feed. The result is a product containing 21 ppm lithium and having a yellowness index of 0.029. After 24 hours, the weight average molecular weight measured by gel permeation chromatography is 195,000 ± 10,000. The reaction mixture is then passed through a 15.2 cm jacket pipe containing 18 15 cm x 20 cm static mixing members (commercially available from Coke Engineering Company). Heat the jacket to a temperature of 120 ° C. and react the 5% by weight ethanol solution in ethylbenzene before feeding the static mixer at a flow rate of about 2.3 kg / hr at four opposite points about 90 ° displaced from adjacent points on the pipe. To supply. After suspension, the partial polymer is devolatile using two non-volatile devices listed in a row, the first nonvolatile device operating at 160 ° C: 79.9 KPa and the second nonvolatile device operating at 240 ° C, 2.65 KPa. .

Example 4

The procedure of Example 2 is repeated except as follows. The feed mixture to the reactor is 42 parts by weight of p-methylstyrene, 2 parts by weight of p-ethyltoluene and 56 parts by weight of ethylbenzene. The feed amount is one reactor volume after 1 1/2 hours. The polymerization temperature is 80 deg. The weight average molecular weight of the product obtained after 24 hours passed was 34,000 ± 30,000. Extrusion of the polymer obtained through the strand die provides strands in the form of lumps or gels that cannot be observed. The product is suitable for extrusion and injection molding of high quality products.

Comparative Example 1

The procedure of Example 2 is repeated except that the stirrer does not rotate. The most suitable control of molecular weight obtained after 24 hours is about ± 100,000. Extrusion of the product yields yellow strands containing large lumps or gels. Molded products from these strands are poor in color and surface appearance.

Comparative Example 2

A jacket tubular reactor 1.2 cm in diameter and 76 cm in length was equipped with color measurements and gel permeation chromatography as described in Example 1. At the rate sufficient to provide a 15 minute residence time to the inlet of the reactor, the weight of the polymerization initiation standard-butyllithium and a mixture of styrene and ethylbenzene (weight: 1) is fed. Air flow is applied to the jacket. The temperature sensing device arranged in the reaction mixture in the reactor indicates that the temperature range is about 20 ° C. Signals controlling the reaction using temperature and gel permeation chromatograph give rise to an average ± 100,000 change in product over 24 hours. The effluent from the reactor contains many visible gels. The product is not useful as a material for extrusion or injection molding.

Comparative Example 3

Use a vertical stirred tube reactor with an internal diameter of 16.5 cm, an internal useful length of 1.40 cm, and a volume of 0.026 cm. The reactor is filled with three nearly identical zones, each protecting the thermoelectric pairs in the reaction mixture. The upper drive stirrer has a straight arm shaft with a diameter of 2.5 cm and 1.3 cm, separated by a 6.3 cm interval on the stirrer shaft. A plurality of fixed rods (1.2 cm in diameter) are radially inwardly installed in the reactor at 6.17 cm intervals. The fixed rod is interconnected with the stirrer upon rotation of the stirrer. The total heat conduction area of the reactor is 1.04 m 2. The physical arrangement of the reactor is based on the vertical axis of rotation. The reaction mixture is very low on the top side of the reactor shaft and the stirrer shaft, while the top to bottom mixture is little. An external line pump is connected between the top and bottom of the reactor. The pump may recycle the contents of the reactor at a rate of 1.5 times per hour. As in Example 2, purified equal parts of styrene and ethylbenzene and standard-butyllithium solution of polymerization initiation were fed to the top of the reactor. The reactant is fed to the reactor at a rate of 1/2 reactor volume per hour with 2 hours remaining. The following temperature relationship is observed.

After 24 hours of operation, the weight average molecular weight can be kept closer than ± 50,000. Most of the polymerization seems to take place in the central region of the reactor. Upon extrusion of the product, such as strands, gels or agglomerates can be observed and the polymer is not satisfactory for extrusion or injection molding.

Claims (10)

The content of the reactor is made nearly uniform and the polymerisation components are added continuously and the reaction mixture is continuously withdrawn from the reactor at about the same rate; A device for controlling the flow rate of monomer and initiator feed into the reactor, and a device for generating a signal to measure the molecular weight of the polymer in the reactor effluent to control the rate of initiator addition into the reactor to provide a polymer of approximately constant molecular weight A method for polymerizing an anionic polymerizable monomer with an organometallic initiator in a continuous stirred tank reactor is further characterized. The method of claim 1 wherein the polymerizable monomer is an alkenylaromatic monomer. The method of claim 1 wherein the polymerizable monomer is styrene. The method of claim 1 wherein the polymerizable monomer is p-vinyltoluene. The process of claim 3 wherein the styrene is diluted with ethylbenzene. The process of claim 5 wherein the weight ratio of ethylbenzene to styrene is about 1: 1. The method of claim 1, wherein the organometallic polymerization initiator compound is butyllithium. The method of claim 1 wherein the reactor is a closed loop type. The method according to claim 1, wherein the first signal is provided which is changed by the molecular weight of the polymer in the effluent from the reactor, and the first signal changes the speed of the polymerization initiator added to the reactor, thereby substantially maintaining the molecular weight of the polymer. Keep it; Measuring the molecular weight of the polymer to generate a second signal; Using the secondary signal to correct for deviations or errors in the primary signal generator to maintain a nearly uniform molecular weight of the polymer in the reactor effluent. Monomer feeder; A monomer flow rate control device connected to an outlet of the monomer supply device; Anion polymerization initiator feeder; An initiator flow rate control device connected to an outlet of the initiator supply device; Continuous stirred tank reactor with inlet and outlet, the inlet of this reactor has a cooperative function of monomer flow rate control device and initiator flow rate control device to receive appropriate amount of material from these two devices. Outlet pipe with cooperative function; A primary signal generator which changes as the molecular weight of the polymer in the effluent from the continuous stirred tank reactor changes, the primary signal controlling the molecular weight of the polymer to be produced by controlling the initiator flow rate; An apparatus for measuring a molecular weight of the polymer and generating a second signal indicating the molecular weight of the polymer; A device for producing an anionically polymerized alkenyl aromatic polymer, characterized in that it comprises a device for receiving a second signal and adjusting the device to provide a first signal to provide a polymer of approximately uniform molecular weight.

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