KR20070023787A - A process for a two stage melt polymerization for the production of polybenzimidazole having an improved solid state polymerization - Google Patents

Abstract

Method for the production of high molecular weight polybenzimidazoles by: (1) providing a first reaction vessel; Filling the reaction vessel with a heterocyclic ring constituting at least one aromatic hydrocarbon tetraamine and dicarboxylic component; Heating the reactant under substantially oxygen free atmosphere until the stirrer torque is about 1.5 times the torque before the viscosity increase begins; Continued heating of the reaction mixture to about 230 ° C. to allow the reactant mass to bubble while terminating stirring; Cooling the reactant mass to a brittle bubbled mass; Crushing the brittle bubbled mass to obtain a pulverized prepolymer; And (2) a second reaction vessel that is a high strength reaction vessel; Transferring the ground prepolymer to a second reaction vessel; The ground prepolymer was heated to about 90 minutes above 315 ° C. at atmospheric pressure with stirring.

High molecular weight polybenzimidazole, tetraamine, dicarboxyl, two stage polymerization.

Description

A two-step melt polymerization process for the production of polybenzimidazoles with improved solid state polymerization.

The present invention provides a two step melt polymerization process for the production of high molecular weight polybenzimidazoles using certain dicarboxylic compounds as monomers.

Ward US Pat. No. 4,672,104 teaches a two step method for the production of polybenzimidazoles. This two-step melt polycondensation method is known to work with significant changes in reactor design corresponding to product thermal history, producing heterogeneous products in Intrinsic Viscosity (IV), solubility, solution filtration quality, color, etc. . Thus, efforts have been undertaken to optimize and improve the second stage SSP (solid state polymerization) reaction mechanism and process conditions.

Ward US Pat. No. 4,717,764 teaches a two-step process for the production of copolymers and fully aromatic polyamides with benzimidazole / aromatic amide polymers.

Polybenzimidazole is a dicarboxylic component consisting of one or more aromatic tetraamines containing two pairs of amine substituents on an aromatic ring so that the amine substituent is in the ortho position relative to the rest, and at least one compound having the formula Prepared by reacting in a step polymerization process:

[Formula 1]

Wherein R ′ is a divalent organic radical, defined in more detail below, which may be the same or different in the various molecules that make up the dicarboxylic component, and Y may be hydrogen, aryl or alkyl, Up to 95% of the total Y in the various molecules that make up can be individually hydrogen or phenyl. Certain polybenzimidazoles made using a combination of the aforementioned monomers are a new composition of matter.

In the first step of the process, the mixture of aromatic tetraamine and dicarboxylic component is heated to a condensation polymerization temperature above the melting point of aromatic tetraamine. Depending on the nature and melting point of the compound or compounds constituting the dicarboxyl component, the resulting polymerization mass may be a liquid which may be a slurry of solid acid particles in molten tetraamine, or a homogeneous mixture of tetraamine and dicarboxyl components and / or Emulsions comprising a molten tetraamine and a molten dicarboxyl component. While stirring vigorously, the mixture under stirring is stirred until the viscosity of the mixture rises to the point where the stirrer torque exceeds about 1.5 times the torque before the viscosity increase begins, and generally does not exceed about 6 times. Continue heating to 230 ° C-350 ° C. Agitation is then terminated and heating continues while the mass is bubbled into a brittle mass. The resulting prepolymer is then cooled, ground to a powder and sent to a second reaction vessel having a stirring means and a pressure or vacuum control means, the second reaction vessel being preferably a high-strength reaction vessel, in the second reaction vessel In the solid state of the second polymerization stage, to a higher temperature than the first stage, to obtain the desired degree of polymerization.

Alternatively, it has been found that improved results can be obtained in the second step by carrying out the solid state polymerization at low positive pressure without the use of a high strength reaction vessel.

Polybenzimidazoles that may be prepared by the process of the invention are those having repeating units of formula

[Formula 2]

Wherein R is a tetravalent aromatic nucleus having a nitrogen atom forming a benzimidazole ring to pair with an adjacent carbon atom of the aromatic nucleus, ie an ortho carbon atom, and R 'is an aromatic ring; Alkylene groups (preferably having 4 to 8 carbon atoms); And heterocyclic rings such as pyridine, pyrazine, furan, quinoline, thiophene and pyran. Depending on whether the dicarboxylic acid moiety in the dicarboxylic monomer component is the same or different, R 'may be the same or randomly different between repeating units along the polymer chain. In addition, depending on whether one or more tetraamine monomers are used in the polymerization, R may also be the same or randomly along the polymer chain.

Scheme 1 below illustrates a condensation reaction to form polybenzimidazoles having repeating units of Formula 2 above:

Scheme 1

Where R. R 'and Y are as previously defined. Such polybenzimidazoles comprise (1) one or more aromatic tetraamines in which each group contains two amine substituents present in the ortho position relative to the rest, and (2) a dicar, as pointed out in the above schemes and more fully defined thereafter. It is produced by reacting a mixture of carboxyl components.

Aromatic tetraamines that may be used are, for example, those having the following formulas 3-1 to 3-5:

[Formula 3-1]

[Formula 3-2]

[Formula 3-3]

[Formula 3-4]

[Formula 3-5]

Where X is --O--, --S--, --SO.sub.2, --C--, or --CH.sub.2--,-(CH.sub.2) sub.2--, or lower alkylene groups such as --C (CH.sub.3) .sub.2 3. Among these aromatic tetraamines, for example, 1,2,4,5-tetraaminobenzene; 1,2,5,6-tetraaminonaphthalene; 2,3,6,7-tetraaminonaphthalene; 3,3 ', 4,4'-tetraaminodiphenyl methane; 3,3 ', 4,4'-tetraaminodiphenyl ethane; 3,3 ', 4,4'-tetraaminodiphenyl-2,2-propane; 3,3 ', 4,4'-tetraaminodiphenyl thioether; And 3,3 ', 4,4'-tetraaminodiphenyl sulfone. Preferred aromatic tetraamines are 3,3 ', 4,4'-tetraaminobiphenyl.

Compounds comprising the dicarboxyl component of the present invention are defined by Formula 1:

[Formula 1]

Wherein Y may be hydrogen, aryl or alkyl, and less than 95% of Y may be hydrogen or phenyl. Thus, the dicarboxylic component may be a mixture of free acid and one or more diesters and / or monoesters; Mixtures of diester (s) and / or monoester (s); Or a single dialkyl ester, monoester or mixed aryl-alkyl or alkyl / alkyl ester, but not completely free acid or diphenyl ester. When Y is alkyl, it preferably contains 1 to 5 carbon atoms, most preferably methyl. When Y is aryl, it may be any monovalent aromatic hydrocarbon group obtained by filling all valences with hydrogen except one of the aromatic groups, which may be R or R 'as described above, as described above. Alternatively, it may or may not be substituted with any inert monovalent radical such as alkyl or alkoxy containing 1 to 5 carbon atoms. Examples of such aryl groups are phenyl, naphthyl, three possible phenylphenyl radicals and three possible tolyl radicals. Preferred aryl groups are usually phenyl.

Dicarboxylic acids in which a free or esterified form as part of the dicarboxylic component as described above, for use in producing polybenzimidazoles by the process of the invention are suitable include aromatic dicarboxylic acids; Aliphatic dicarboxylic acids (preferably those having 4 to 8 carbon atoms); And heterocyclic dicarboxylic acids wherein the carboxyl group is a substituent on a carbon atom in a ring compound such as pyridine, pyrazine, furan, quinoline, thiophene and pyran.

Preferred dicarboxylic acids which can be used in free or esterified form as described are aromatic dicarboxylic acids as exemplified below:

Where X is as defined above. For example, the following diacids may suitably be used: isophthalic acid; Terephthalic acid; 4, 4'-biphenyldicarboxylic acid; 1,4-naphthalenedicarboxylic acid; Diphenic acid (2,2'-biphenyldicarboxylic acid); Phenyl indandicarboxylic acid; 1,6-naphthalenedicarboxylic acid; 2,6-naphthalenedicarboxylic acid; 4,4'-diphenyletherdicarboxylic acid; 4,4'-diphenylsulfondicarboxylic acid; 4,4'-diphenylthioetherdicarboxylic acid. Isophthalic acid is dicarboxylic acid in free or esterified form, or diphenyl isophthalate (1,3-benzene dicarboxylic acid, diphenyl ester) is most preferred for use in the process of the invention.

Preferably the dicarboxylic component is one of the following combinations: (1) one or more free dicarboxylic acids and one or more diphenyl esters of dicarboxylic acids; (2) dialkyl esters of one or more free dicarboxylic acids and one or more dicarboxylic acids, and (3) diphenyl esters of one or more dicarboxylic acids and dialkyl esters of one or more dicarboxylic acids; And (4) dialkyl esters of one or more dicarboxylic acids. The dicarboxyl moieties of the compounds of each combination may be the same or different and the alkyl groups of the alkyl esters of the combinations (2), (3) and (4) generally contain 1 to 5 carbon atoms and most preferably methyl to be.

Preference is given to using the dicarboxyl component in a proportion of about 1 mole of the total dicarboxylic component per mole of aromatic tetraamine. However, the appropriate proportion of reactants in a particular polymerization system can be readily determined by one skilled in the art.

Examples of polybenzimidazoles that can be prepared according to the process of the invention include the following:

Poly-2,2 '-(m-phenylene) -5,5'-bibenzimidazole;

Poly-2,2 '-(biphenylene-2 "2"')-5,5'-bibenzimidazole,

Poly-2,2 '-(biphenylene-4 "4"')-5,5'-bibenzimidazole;

Poly-2,2 '-(1 ", 1", 3 "trimethylindenylene-3" 5 "-p-phenylene-5,5'-bibenzimidazole;

2,2 '-(m-phenylene) -5,5'-bibenzimidazole / 2,2- (1 ", 1", 3 "-trimethylindenylene) 5", 3 "-(p- Phenylene) -5,5'-bibenzimidazole copolymer;

2,2 '-(m-phenylene) -5,5-bibenzimidazole / 2,2'-biphenylene-2 ", 2"')-5,5'-bibenzimidazole copolymer;

Poly-2,2 '-(furylene-2 ", 5")-5,5'-bibenzimidazole;

Poly-2,2 '-(naphthalene-1 ", 6")-5,5'-bibenzimidazole;

Poly-2,2 '-(naphthalene-2 ", 6")-5,5'-bibenzimidazole;

Poly-2,2'-amylene-5,5'-bibenzimidazole;

Poly-2,2'-octamethylene-5,5'-bibenzimidazole;

Poly-2,2 '-(m-phenylene) -diimidazobenzene;

Poly-2,2'-cyclohexenyl-5,5'-bibenzimidazole;

Poly-2,2 '-(m-phenylene) -5,5'-di (benzimidazole) ether;

Poly-2,2 '-(m-phenylene) -5,5'-di (benzimidazole) sulfide;

Poly-2,2 '-(m-phenylene) -5,5'-di (benzimidazole) sulfone;

Poly-2,2 '-(m-phenylene) -5,5'-di (benzimidazole) methane;

Poly-2,2 "-(m-phenylene) -5,5" -di (benzimidazole) propane-2,2; And

Poly-ethylene-1,2-2,2 "-(m-phenylene) -5,5" -dibenzimidazole) ethylene-1,2.

Wherein the double bond of the ethylene group does not change in the final polymer.

Preferred polybenzimidazoles prepared by the process of the invention are poly-2,2 '-(m-phenylene) -5,5'-bibenzimidazoles, the repeating units of which n is an integer greater than 75 to be. This polymer comprises a combination of 3,3 ', 4,4'-tetraaminobiphenyl with isophthalic acid having a dialkyl isophthalate, such as diphenyl isophthalate or dimethyl isophthalate, according to the process of the invention; Combinations of dialkyl isophthalates with dialkyl isophthalates such as dimethyl isophthalate; Or by reacting with one or more dialkyl isophthalates such as dimethyl isophthalate as the sole dicarboxyl component.

The process of the invention can be used to prepare polybenzimidazoles from one or more aromatic tetraamines and one or more dicarboxylic acids. Generally, stoichiometric amounts of total tetraamine and dicarboxyl components, or some molar excess of dicarboxylic components, are used.

Intrinsic viscosity (hereinafter “IV”) is the ratio of the specific viscosity of a solution of known concentration to the concentration of extrapolated solute to zero concentration, measured in units of dL / g. Intrinsic or intrinsic viscosity is also referred to as extreme viscosity frequency. This is directly proportional to the polymer average molar weight. dL / g, IV (inherent viscosity) measurements are based on the concentration (g / 100 ml or g / deciliter) of the polymer sample to be tested. The polymer is dissolved at a level of 0.4% (w / v) in 100 ml of 96.5% (+/- 0.5%) sulfuric acid at 80 ° C. After filtration, the IV of the aliquot was measured using a Cannon-Fenske capillary viscometer calibrated in a 25 +/- 0.1 C water bath and the flow of PBI polymer solution measured according to the solvent for dissolution Measure the time (sec.). IV = ln (tl / t2) / c, where the natural logarithm of the flow time t1 of the PBI solution to the flow time t2 of the solvent is divided by the PBI solution concentration.

The first step of the process of the invention is carried out by heating the aromatic tetraamine, dicarboxyl component in a first reaction vessel with vigorous stirring to a temperature in the range of 230 ° C.-350 ° C., preferably 280 ° C.-340 ° C. do. Depending on the melting point of the dicarboxylic component compounds and the chemical properties of the tetraamine and dicarboxylic components, the stirred liquid mass will be a slurry, homogeneous mixture or emulsion of two immiscible liquids. When the viscosity of the reaction mass begins to rise as indicated by the increased stirrer torque enhanced by the increased stirring energy, the stirring is stopped and the mass is further heated to bubble. At the point at which stirring is stopped, the stirrer torque and stirring energy generally do not exceed about 1000% of the initial torque or stirring energy, for example after melting of the tetraamine, and preferably not more than about 300%. The mass is then further heated to a temperature in the range of, for example, about 230 ° C. to 350 ° C., preferably about 280 ° C. to 340 ° C., without stirring the mass. This heating is continued for a time, for example, in the range of about 0.25 to 3 hours, preferably about 0.5 to 1.5 hours. The bubbled mass is then cooled to a temperature below its melting point, such as room temperature, to become a brittle solid mass that is easily crushed or crushed. The cooling step can generally place the reaction mass at 35 ° C. to 15 ° C., preferably cooling to room temperature which is perceived as on the order of 20 ° C. to 25 ° C. Generally, the intrinsic viscosity of the prepolymer after the first step is complete, for example, in the range of about 0.05 to 0.3 dl / g, (all intrinsic viscosity measured at 0.4% by weight of polymer solution in 96.5% sulfuric acid at 25 ° C). do.

The milled prepolymer is then transferred to a second high intensity reaction vessel. The high strength reaction vessel has stirring means, temperature regulating means and pressure or vacuum regulating means. Installing this vessel away from the vessel used in the first stage of the reaction is a means to make stirring more active and to agitate the ground prepolymer in a solid state. Such high intensity reactors include, but are not limited to, rotary furnaces, fluidized beds, static mixers, stirred autoclaves or glassware, continuous kneading reactors, positive rotating processors, co-rotating processors, and single shaft rotating processors. It is not limited. Such high intensity mixers can be purchased from a variety of sources, including but not limited to: Komax Systems Inc., Wilmington, CA; Koch-Glitsch, Wichita, KS; Carbolite, Watertown, WI; LIST Charlotte, NC; Processall, Cinncinnati, OH; Procedyne Corp. It is also possible to convert a standard mixing vessel into a high-strength reaction vessel by changing the stirrer blade to use most of the mixture, using a larger or stronger stirrer motor, and using additional stirrers or combining them.

By the use of high-strength mixers, the solid state polymerization process and product data / results are improved with improved IV uniformity at higher conventional production temperature performance (up to 400 ° C.) and reduced reaction time compared to current conventional manufacturing methods. It shows higher IV target performance, or vice versa the ability to meet the product IV target at lower production temperatures (335 ° C. vs. 345 ° C.-370 ° C.). This provides additional fluidity in using the temperature to adjust the desired IV target. Surprisingly, the plugging value of the resulting product is operating much higher than the current commercially available product.

After transferring the milled prepolymer to the second reaction vessel, during the second step, the milled prepolymer is heated to 315 ° C to 400 ° C, preferably 330 ° C to 400 ° C, with stirring. If the IV target is less than 1.0 dL / g, temperatures of 330 ° C to 350 ° C can be used. If IV exceeds 1.0 dL / g, temperatures of 355 ° C to 400 ° C are preferred. When heating the pulverized prepolymer with stirring, a weak positive pressure is used and this weak positive pressure is at atmospheric pressure, equivalent to 2 mbar to 30 mbar, 0.25 inch H ₂ O to 5 inch H ₂ O, or 0.63 cm H ₂ O to 13 cm of H ₂ O. The ground prepolymer is heated for 90 minutes to 400 minutes, preferably 200 minutes to 360 minutes or 220 minutes to 330 minutes.

Polybenzimidazoles are used for different purposes depending on their particle size. Polybenzimidazoles having an average particle size (PS) of less than 150 microns are generally commonly used as polymers and should have a minimum intrinsic viscosity of 0.5. In order to produce extruded fibers and extruded films, it is generally desirable to have particles of at least 300 microns having an intrinsic viscosity (IV) of at least about 0.8. For use as a fuel cell membrane, larger particle sizes in excess of 300 microns are used and an intrinsic viscosity of at least 0.9, preferably 1.1 is required.

In both steps of the process of the invention, the pressure is preferably at least atmospheric pressure, such as 1 or 2 atmospheres, preferably at atmospheric pressure. This pressure is typically obtained by using an open polymerization system with a condenser to remove condensation compounds that are produced as byproducts of the reaction.

Both steps of the production process are carried out in an atmosphere substantially free of oxygen. For example, an inert gas such as nitrogen or argon may be passed through the reaction zone continuously during the polymerization. The inert gas used should be substantially free of oxygen, in other words less than about 20 parts per million (ppm), preferably less than about 8 ppm, more preferably free of oxygen. Inert gas is introduced into the reaction zone at flow rates measured at standard conditions, i.e. atmospheric pressure and temperature, within a range of about 1 to 200 percent of the volume of the reaction zone per minute. The inert gas can be preheated at room temperature, if desired, to the reaction temperature and passed to the polymerization reaction zone. One way to obtain a substantially oxygen free atmosphere is to pump N ₂ into the reaction chamber at a rate of 0.6 standard liters per minute (SLPM) to 4.6 SLPM. In the first step, the reactants may be placed under a slight vacuum, typically Hg of 10 cm to 46 cm.

The process of the present invention can be used to produce high molecular weight polybenzimidazole products having a relatively high intrinsic viscosity. This product exhibits an intrinsic viscosity of at least about 0.6 dl / g when measured at a concentration of 0.4 g of polymer in 100 ml of 96.5 percent H ₂ SO ₄ at 25 ° C. for particles having a size in the range from 300 to 1000 microns. Preferably, the polymer exhibits an intrinsic viscosity of at least about 0.8 dl / g, and most preferably at least about 1.0 dl / g.

Using the method of the present invention, it is possible to obtain an average intrinsic viscosity of at least 0.6 dL / g for all particles having a size in the range from 150 microns to 1000 microns. This can be obtained in a two step method. The first step is started by providing a first reaction vessel with stirring means and atmospheric control means. The reaction vessel is then charged with at least one aromatic hydrocarbon tetraamine containing two pairs of amine substituents at the ortho position of the aromatic ring and a dicarboxyl component consisting of at least one compound having the formula

[Formula 1]

Where R 'is a divalent organic radical of the group consisting of an aromatic hydrocarbon ring, an alkylene group and a heterocyclic ring, which may be the same or different in the various molecules constituting the dicarboxyl component, and Y is hydrogen, aryl or alkyl And 95% or less thereof is hydrogen or phenyl to produce a reaction mass. A vacuum of 10 cm Hg to 46 cm Hg is then formed and the reaction is heated in an atmosphere substantially oxygen free with stirring until the stirring torque is about 1.5 to about 6 times the torque before the viscosity increase begins. At this point, stirring is terminated while the reaction mixture is continuously heated to a temperature of 230 ° C. to 350 ° C. so that the reaction mass can be bubbled. The reaction mass is cooled to a brittle bubbled mass that will soon be crushed to obtain a pulverized prepolymer. A second step is initiated by providing a second reaction vessel with agitation means and pressure or vacuum control means and transferring the ground prepolymer to the second reaction vessel. The ground prepolymer is heated at 315 ° C. to 400 ° C., at a slight positive pressure, with stirring for 90 to 400 minutes. Current conventional processes generally require the milled prepolymer to be heated to at least 350 ° C. to obtain an IV exceeding 0.6 dL / g. However, plugging values are typically consistently below 6 g / cm ² and in many cases tend to fall below 3 g / cm ² . Surprisingly, in the present invention, it is possible to obtain an average intrinsic viscosity of at least 0.7 dL / g for all particles in the size range of 150 microns to 1000 microns, wherein the ground prepolymer is heated to a range of 330 ° C. to 350 ° C. and is 10 g. Plugging values of / cm ² or greater can also be obtained. In the present invention, by raising the reaction temperature to 355-400 ° C., it is possible to obtain an average intrinsic viscosity of 1.0 dL / g or more for all particles in the size range of 150 microns to 1000 microns, and also to obtain a plugging value of 10 or more. Can be.

The following examples further illustrate the invention. The intrinsic viscosity (IV) mentioned in the examples was determined as a 0.4% solution in sulfuric acid at 96.5% concentration at 25 ° C., and a 5% solution of polymer in 96.5% sulfuric acid or a 6% solution in dimethyl acetamide containing 2% lithium chloride. And the plugging value (PV, solubility / filtration scale, subsequent polymer solution quality followed by fiber and film extrusion capacity and quality by filtering the solution through a Gelman Type A glass paper filter at 25 ° C., 1 atmosphere pressure. The key to defining this is measured. Plugging values, the number of grams of polymer solution filtered per unit area for infinite time, are expressed in grams of polymer per square centimeter. Higher values indicate that the polymer solution contains less gel and insoluble matter. Gels are defined herein as insoluble, deformable, polymer-like particles, polymers that are most readily degraded or crosslinked.

SSP testing showed the preparation of PBI polymer in the range of 0.5-1.1 dl / g at the second stage reaction temperature and time. Final polymer product properties--including color, PV, "gel" level, particle size distribution, and density--are monomer stoichiometry, exposure to oxygen, vacuum / pressure / atmosphere conditions, stirring rate, phenol level, and monomer purity (Potentially by other factors such as tetraaminobiphenyl (TAB)).

The preceding rotary reactor bench-scale test showed that the SSP had a first stage stoichiometry (with or without excess diphenyl isophthalate (DPIP)), nitrogen gas flow rate, temperature (350 ° C.-380 ° C.) and It was shown how affected by the first stage prepolymer particle size. With the appropriate choice of prepolymer stoichiometry, particle size and polymerization temperature and time, it has been demonstrated that gel-free polymers can be produced with a predetermined IV.

The first stage raw material can be prepared using conventional methods, ie using 0.6% molar excess of DPIP monomer. Excess DPIP reduces the potential for free TAB, and DPIP can potentially distill the reactor with free phenol. With reactor agitation, polymer particles are expected to decrease, homogeneity of the product is increased, and IV growth is expected to depend on particle size. Although smaller size particles are not produced as much as in the second stage (see IV according to particle size distribution data for <300 micron particle size range), grinding of the prepolymer (such as pin milling) is a thermal transition. And particularly promote particle size control for 100 mesh products (<150 microns), but not for high IV products. Although smaller particles provide better / more homogeneous heat transfer, it is clear that the reduced surface area makes the removal of phenol and water more difficult and then reduces IV growth. Particles with low IV, larger size can result from poor thermal transitions. IV appears to significantly advance polymerization to various molar weight species with thermal history, depending on the IV and size of the individual particles. The longer the reaction time at higher temperature, the IV increases, but will ultimately decrease without controlling the PV.

For high IV fuel cell grade polymers, non-LiCl solution will be easier for small particle size, i.e. <500 microns, at a 1.1 IV minimum. In addition, the higher the IV (> 1.2), the better the mechanical stability of the resulting film is produced and aged. The desired IV and particle size can be separated and filtered based on the IV according to the PSD data, and the final product can be made to the desired target IV and particle size, or range.

Other unusual polymer characterization and quality tests included the following for direct comparison with commercial products.

Gel levels were measured by preparing a 0.4% (w / v) polymer solution in 97% sulfuric acid in a stoppered bottle and stirring for 48 hours at room temperature. The solution was filtered through a calcined glass crucible (ASTM type 10-15 microns). The insoluble portion was washed with ammonia solution and then water and dried in vacuo at 140 ° C. for 8 hours; Gel content was determined by gravimetry. Negligible gel levels indicate negligible insoluble matter and good solution quality.

A polymer sample for gel permeation chromatography (GPC) analysis was prepared by filling a Parr reactor with 5 mg of sample and 20 ml of 0.05N lithium chloride (LiCl) in dimethyl acetamide (DMAc). After the reactor was tightly locked, it was placed in an oil bath and the temperature was maintained at 180 ° C. for 12 hours. The solution is filtered through a 0.2 micron syringe filter and 100 microliters aliquots are injected onto a GPC column (PSS polyolefin linear XL). GPC separations are performed using 0.05N LiCl, 1 ml / min flow rate, 65 ° C., 4.7 MPa pressure, refractive index index detection, broad molecular weight distribution (MWD) polymer standard for PMMA (polymethyl methacrylate) in DMAc eluent. . The narrow MWD (target <3.0 polydispersity) of the SSP test product exemplified in the examples of the method is characterized by the narrow molecular weight (MW / IV) and the mechanical properties required for the extruded film and membrane aimed at improved extrusion / spinning performance. Directly corresponded to

A sample, measured at 3-4 mg, was placed in a glass reaction bottle to prepare a polymer solution for nuclear magnetic resonance (NMR) by adding 1 ml of 96% deuterated sulfuric acid. The capped vial was shaken for 2 days at room temperature to form a complete solution. Proton NMR spectral scans were obtained using a Varian Unity 300 spectrometer.

Test results have been found to be typical or better for ordinary commercial products.

Control Samples for Comparative Test

Control samples were obtained from three batchers prepared by conventional methods. These batches were chosen to include an IV range of 0.74 to 1.10 to compare the test data with normal conventional products. However, in order to produce this conventional batch in this IV range, the current production had to be made at higher temperatures with longer reaction times for the higher IV range. These samples are common commercially produced samples and therefore represent polymers that must be sieved to remove 100 mesh particles (<150 microns): batches 1-120 / 2-119-02PM, 1-121-02 and 2 -112-02 is indicated in the table as Control A, Control B and Control C.

The first stage polymer from batch 137-02 was prepared using current commercial reaction vessels and using the normal first stage method. After crushing the product, the vessel was warmed to 290 ° C. for a 75 minute down time. The vessel was cooled and the polymer was collected from the reactor for the second step. A first step was similarly prepared from batch 138-02 except that it was a 90 minute dwell time at 290 ° C. The "stop" time is the process time added earlier in the reaction sequence after a typical first stage reaction, in order to promote removal of the phenol condensate and not adversely affect the polymer reactants. Process time was added to a typical subsequent second stage reaction, and crosslinking could be promoted at higher temperatures, thus inhibiting growth of IV or molar weights. Polymer solubility and filtration quality are positively influenced through earlier "stop time" or single step methods.

Test sample

Example J1: 13.34 lbs., Twin shaft, 209 ° C. vessel from batch 1-093-02 filled in a LIST CRP-10 batch; Vessel pressure of 16 mbar g; Stirring at 16 rpm; N ₂ flow of 3 SCFH (standard cubic feet per hour), or 1.42 SLPM (standard liters per minute) at standard temperature (0 ° C.) and pressure (1 atm); Elevated temperature to 325 ° C. target at 137 ° C./hr; Total polymerization time of 240 minutes measured from 320 ° C .; Then take a sample.

Example J2: 9.99 lbs from 1-093-02 charged at ambient temperature. (Centercut, ie> 50 mesh or> 300 micron particle size); Same agitation, N ₂ flow and pressure as described above; Warming up to a target of 343 ° C. at 172 ° C./hr; Total polymerization time of 240 minutes, measured from 330 ° C .; Take a sample as described above.

Example J3: 9.99 lbs. From batch 1-093-02 filled in the vessel at ambient temperature; Same agitation, N ₂ flow and pressure as described above; Raise the temperature to 343 ° C. target at 83 ° C./hr (due to failure of the heater, keep the product at 130 ° C. for 40 minutes); Total polymerization time of 300 minutes, measured from 330 ° C .; Take a sample.

Example O1: 5.7 lbs. From batch 1-137-02 filled in LIST 6.3, single shaft, vessel at 200 ° C .; 2 inches H ₂ O positive pressure (5.1 cms H ₂ O positive pressure); Stirring at 20 rpm; 3 SCFH (standard cubic feet per hour) or 1.42 SLPM (standard liters per minute) N ₂ flow at standard temperature (0 ° C.) and pressure (1 atm); Elevated temperature to 328 ° C target at 141 ° C / hr; Total polymerization time measured from 312 ° C. 255 minutes; Then take a sample.

Example 02: 5.7 lbs. From batch 1-138-02 filled in vessel at ambient temperature; 2 inches H ₂ O positive pressure (5.1 cms H ₂ O positive pressure); Stirring at 20 rpm; N ₂ flow at 3 SCFH (standard cubic feet per hour) or 1.42 SLPM (standard liters per minute) at standard temperature (0 ° C.) and pressure (1 atm); Raise the temperature to 122 ° C./hr to the 328 ° C. target; Total polymerization time of 300 minutes, measured from 312 ° C .; Then take a sample.

Example 03: 5.7 lbs. From batch 1-137-02 filled to vessel at ambient temperature; Same agitation, pressure and N ₂ flow conditions as described above; Elevated temperature to 338 ° C. target at 132 ° C./hr; Total polymerization time of 300 minutes, measured from 323 ° C .; Then take a sample.

Example 04: 5.7 lbs. From batch 1-138-02 filled to vessel at ambient temperature; Same agitation, pressure and N ₂ flow conditions as described above; Elevated temperature to 338 ° C. target at 149 ° C./hr; Total polymerization time of 300 minutes, measured from 323 ° C .; Then take a sample.

The following properties of the final polymer product were checked for both the control sample and the examples: IV (and IV according to particle size distribution), PV (plugging value, or filtration performance), L color, gel level, and GPC (gel Molar weight distribution) and NMR (nuclear magnetic resonance) spectroscopy by permeation chromatography.

Gels are defined herein as insoluble, deformable, polymer-like particles, polymers that are most readily degraded or crosslinked. PV is a measure of solubility / filtration and is key to defining solution quality and subsequent fiber extrusion capacity and quality. "L" color refers to the color level for whiteness on the color scale, the higher the value, the lighter the color appears. NMR, or nuclear magnetic resonance, is effective for observing the molecular structure of the product. Polymer samples and products were tested in several of these ways to further characterize the chemical and physical properties of the resulting polymers, and the product was characterized as polybenzimidazole.

IV (and particle size distribution, IV according to PSD) and PV are provided below. L color, gel level, and molar weight distribution by GPC (gel permeation chromatography) and NMR (nuclear magnetic resonance) spectroscopy are considered to be acceptable by the current standard unless otherwise noted.

Claims (20)

A two-step melt polymerization process for producing high molecular weight polybenzimidazole in the first and second steps, The first step is, Providing a first reaction vessel having agitation means and atmospheric control means; Filling said reaction vessel with at least one aromatic hydrocarbon tetraamine containing two pairs of amine substituents at the ortho position of the aromatic ring and a dicarboxyl component comprising at least one compound having the formula [Formula 1]

Wherein R 'is a divalent organic radical of the group consisting of an aromatic hydrocarbon ring, an alkylene group and a heterocyclic ring, which may be the same or different in the various molecules making up the dicarboxyl component, and Y is hydrogen, aryl or Alkyl, and up to 95% of Y is hydrogen or phenyl to produce a reaction mass); Heating the reactant under stirring in an atmosphere substantially oxygen free while stirring until the stirrer torque is about 1.5 to about 6 times the torque before the viscosity increase begins; Continuing the heating of the reaction mixture to a temperature of 230 ° C. to 350 ° C. while ending the stirring to allow the reaction mass to bubble; Cooling the reaction mass to a brittle bubbled mass; And Crushing the brittle bubbled mass to obtain a pulverized prepolymer, The second step, Providing a second reaction vessel, which is a high strength reaction vessel, having a stirring means and a pressure or vacuum control means; Transferring the ground prepolymer to the second reaction vessel; And Heating the ground prepolymer with stirring at 315 ° C. to 400 ° C. for 90 to 400 minutes at atmospheric pressure, A two stage melt polymerization process for producing high molecular weight polybenzimidazoles. The method of claim 1, The two-step melt polymerization process for producing high molecular weight polybenzimidazole, wherein the heating and stirring step in the second step is carried out at a weak positive pressure. The method of claim 2, And wherein said weak positive pressure in said second stage corresponds to between 2 mbar and 30 mbar. The method of claim 2, The weak positive pressure in the second step is for producing high molecular weight polybenzimidazoles, corresponding to 0.25 inches of H ₂ O to 5 inches of H ₂ O, or 0.63 cm of H ₂ O to 13 cm of H ₂ O. Two stage melt polymerization method. The method of claim 2, The second step melt polymerization method for producing a high molecular weight polybenzimidazole, wherein the heating in the second step is carried out for 200 to 320 minutes. The method of claim 1, In the second step, the milled prepolymer was heated with stirring from 330 ° C. to 350 ° C. at a slight positive pressure for 220 to 330 minutes, with an average intrinsic of at least 0.7 dL / g for all particles ranging in size from 150 microns to 1000 microns A two-step melt polymerization process for producing high molecular weight polybenzimidazole, which produces a high molecular weight polybenzimidazole having a viscosity. The method of claim 6, Wherein said high molecular weight polybenzimidazole has a plugging value of 10 g / cm ² or more, and a two-step melt polymerization method for producing high molecular weight polybenzimidazole. A two-step melt polymerization process for producing high molecular weight polybenzimidazole in the first and second steps, The first step is, Providing a first reaction vessel having agitation means and atmospheric control means; Filling said reaction vessel with at least one aromatic hydrocarbon tetraamine containing two pairs of amine substituents at the ortho position of the aromatic ring and a dicarboxyl component comprising at least one compound having the formula [Formula 1]

Wherein R 'is a divalent organic radical of the group consisting of an aromatic hydrocarbon ring, an alkylene group and a heterocyclic ring, which may be the same or different in the various molecules making up the dicarboxyl component, and Y is hydrogen, aryl or Alkyl, and up to 95% of Y is hydrogen or phenyl to produce a reaction mass); Forming a vacuum of 10 cm Hg to 46 cm Hg; Heating the reactant under stirring in an atmosphere substantially oxygen free with stirring until the stirrer torque is about 1.5 times to about 6 times the torque before the viscosity increase begins; Continuing the heating of the reaction mixture to a temperature of 230 ° C. to 350 ° C. while ending the stirring to allow the reaction mass to bubble; Cooling the reaction mass to a brittle bubbled mass; And Crushing the brittle bubbled mass to obtain a pulverized prepolymer, The second step, Providing a reaction vessel having a stirring means and a pressure or vacuum control means; Transferring the ground prepolymer to the reaction vessel; And Heating the ground prepolymer with stirring at low positive pressure for 90 minutes to 400 minutes to 315 ° C to 400 ° C, A two stage melt polymerization process for producing high molecular weight polybenzimidazoles. The method of claim 8, And wherein said weak positive pressure in said second stage corresponds to between 2 mbar and 30 mbar. The method of claim 8, The weak positive pressure in the second step is for producing high molecular weight polybenzimidazoles, corresponding to 0.25 inches of H ₂ O to 5 inches of H ₂ O, or 0.63 cm of H ₂ O to 13 cm of H ₂ O. Two stage melt polymerization method. The method of claim 8, The second step melt polymerization method for producing a high molecular weight polybenzimidazole, wherein the heating in the second step is carried out for 200 to 320 minutes. The method of claim 8, In the second step, the milled prepolymer was heated with stirring from 330 ° C. to 350 ° C. at a slight positive pressure for 220 to 330 minutes, with an average intrinsic of at least 0.7 dL / g for all particles ranging in size from 150 microns to 1000 microns A two-step melt polymerization process for producing high molecular weight polybenzimidazole, which produces a high molecular weight polybenzimidazole having a viscosity. The method of claim 12, The high molecular weight polybenzimidazole has a plugging value of 10 g / cm ² or more, a two-step melt polymerization method for producing a high molecular weight polybenzimidazole. The method of claim 8, In the second step, the milled prepolymer was heated with stirring from 355 ° C. to 400 ° C. at a weak positive pressure for 200 to 360 minutes, with an average intrinsic value of at least 1.0 dL / g for all particles ranging in size from 150 microns to 1000 microns. A two-step melt polymerization process for producing high molecular weight polybenzimidazole, which produces a high molecular weight polybenzimidazole having a viscosity. The method of claim 14, The high molecular weight polybenzimidazole has a plugging value of 10 g / cm ² or more, a two-step melt polymerization method for producing a high molecular weight polybenzimidazole. A two-step melt polymerization process for producing high molecular weight polybenzimidazole in the first and second steps, The first step is, Providing a first reaction vessel having agitation means and atmospheric control means; Filling said reaction vessel with at least one aromatic hydrocarbon tetraamine containing two pairs of amine substituents at the ortho position of the aromatic ring and a dicarboxyl component comprising at least one compound having the formula [Formula 1]

Wherein R 'is a divalent organic radical of the group consisting of an aromatic hydrocarbon ring, an alkylene group and a heterocyclic ring, which may be the same or different in the various molecules making up the dicarboxyl component, and Y is hydrogen, aryl or Alkyl, and up to 95% of Y is hydrogen or phenyl to produce a reaction mass); Forming a vacuum of 10 cm Hg to 46 cm Hg; Heating the reactant under stirring in a substantially oxygen free atmosphere while stirring until the stirrer torque is between about 1.5 and about 6 times the torque before the viscosity increase begins (wherein the substantially oxygen free atmosphere is Contains less than 20 ppm oxygen and includes an N ₂ flow of 0.6 SLPM to 4.6 SLPM); Continuing to heat the reaction mixture to a temperature of 250 ° C. to 380 ° C. while ending the agitation, allowing the reaction mass to bubble; Cooling the reaction mass to a brittle bubbled mass up to 35 ° C. to 15 ° C .; And Crushing the brittle bubbled mass to obtain a pulverized prepolymer, The second step, Providing a reaction vessel having a stirring means and a pressure or vacuum control means; Transferring the ground prepolymer to the reaction vessel; And Heating the milled prepolymer with stirring at a weak positive pressure for 200 minutes to 360 minutes at 330 ° C. to 350 ° C .; And Producing a high molecular weight polybenzimidazole having an average intrinsic viscosity of at least 0.7 dL / g and a plugging value of at least 10 g / cm ² for all particles in a size range of at least 150 microns and at most 1000 microns, A two stage melt polymerization process for producing high molecular weight polybenzimidazoles. The method of claim 16, The weak positive pressure in the second step is for producing high molecular weight polybenzimidazoles, corresponding to 0.25 inches of H ₂ O to 5 inches of H ₂ O, or 0.63 cm of H ₂ O to 13 cm of H ₂ O. Two stage melt polymerization method. The method of claim 16, The second stage melt polymerization process for producing high molecular weight polybenzimidazole in a second stage, wherein the second reaction vessel is a high strength reaction vessel. The method of claim 16, Wherein said aromatic tetraamine is 3,3 ', 4,4'-tetraaminobiphenyl, to produce high molecular weight polybenzimidazole. The method of claim 16, Wherein said dicarboxyl component is diphenyl isophthalate.