United States Patent (19) 11 Patent Number: 4,814,228 Onorato et al. (45) Date of Patent: Mar. 21, 1989 (54) WET SPUN HYDROXYETHYLATED (56) References Cited POLYBENZMIDAZOLE FIBERS U.S. PATENT DOCUMENTS (75) Inventors: Frank J. Onorato, Phillipsburg; 3,851,025 11/1974 Ram .................................... 264/184 Michael J. Sansone, Berkeley 4,599,388 7/1986 Bower et al. ... ... 525/433 Heights; Arthur Schlask, Roselle 4,734,466 3/1988 Kindler et al....................... 525/433 Park, all of N.J. Primary Examiner-Lorraine T. Kendell Attorney, Agent, or Firm-Lynch, Cox, Gilman & 73 Assignee: Hoechst Celanese Corporation, Mahan Somerville, N.J. 57) ABSTRACT 21 Hydroxyethylated polybenzimidazole fibers are pro Appl. No.: 28,354 duced by a wet jet/wet spinning or by a dry jet/wet spinning process. A spinning solution of hydroxye 22 Filed: Mar. 20, 1987 thylated polybenzimidazole is extruded vertically downward through a spinneret into a liquid coagulation (51) Int. Cl." ............................................... D02G 3/00 bath. The resulting fibers have pore sizes ranging from (52) U.S. Cl. ............................... 428/398; 210/500.28; about 5 angstroms up to about 100 angstroms and are 210/500.23; 264/41; 264/183; 264/184; quite useful as ultra filters for molecules with a broad 264/210.8; 428/376 range of molecular weight. 58 Field of Search ............... 428/364, 392,397, 398, 428/376; 264/183, 184, 41,210.8; 210/500.28 17 Claims, No Drawings 4,814,228 1. 2 ample, such polybenzimidazole polymers as poly WET SPUN HYDROXYETHYLATED 2,2'(m-phenylene)-5,5'-bibenzinidazole and other simi POLYBENZMDAZOLE FIBERS larly structured polybenzimidazole polymers may not be used because the bridging groups between the reac BACKGROUND OF INVENTION 5 tive imidazole rings are sterically hindered, thereby 1. Field of Invention severely restricting the reactivity of the imidazole nitro This invention relates to substituted polyben gens. Further, the '644 patent fails to disclose any pro zimidazole articles and the process for their production. cess for the production of hydroxyl modified polyben More particularly the invention relates to hydroxye thylated polybenzimidazole fibers and the process for 10 zimidazole fibers, membranes or other shaped articles. their production. An additional process for the production of hydroxyl 2. Prior Art modified polybenzimidazole is disclosed in U.S. Pat. Polybenzimidazoles are a known class of heterocy No. 4,599,388. clic polymers which are characterized by a high degree Further processes for the production of substituted of thermal and chemical stability. Processes for their 15 polybenzimidazoles are disclosed in U.S. Pat. Nos. production are disclosed in U.S. Pat. No. Re. 26,065, 4,579,915, 4,377,546, 3,943,125 and 3,518,234. U.S. Pat. and U.S. Pat. Nos. 3,313,783, 3,509,108, 3,555,389, No. 4,579,915, discloses substituted polybenzimidazole 3,433,772, 3,408,336, 3,549,603, 3,708,439, 4,154,919, polymers wherein the imidazole hydrogen is replaced and 4,312,976. (All patents enumerated hereof are incor by an aromatic substituent corresponding to the for porated by reference.) 20 mula: Fibers produced from polybenzimidazole polymers retain these favorable attributes and can be useful in a broad range of applications. For example, polyben zimidazole filaments have been utilized for electrodialy sis, reverse osmosis, and for a wide range of other 25 separatory uses. However, because the pore size of unsubstituted polybenzimidazole fibers is quite small, i.e. less than about 1 angstrom, polybenzimidazole fibers R are not useful as filters for molecules having molecular weights greater than about 1000. 30 where R is nitro, cyano, or trifluoromethyl and R' is Further, although polybenzimidazole polymers are hydrogen, alkyl, nitro, cyano or trifluoromethyl. generally resistant to chemical reaction, the imidazole U.S. Pat. No. 4,377,546 discloses a phenol substituted nitrogen-hydrogen bond on the polybenzimidazole pol polybenzimidazole but does not disclose a process for ymer is susceptible to reaction under certain conditions. its preparation. Polybenzimidazole fibers have been produced by two 35 U.S. Pat. No. 3,943,125 discloses a broad range of basic processes. The first is dry spinning, which in substituted tetraamino heterocyclic compounds useful volves spinning a polybenzimidazole solution through a in the preparation of substituted polybenzimidazoles. spinneret into an evaporative chamber. The second is However, the patent fails to disclose hydroxyethylated wet spinning wherein the spinning solution is spun polybenzimidazole polymers or a process for the pro through a spinneret either directly into a coagulation duction of hydroxyethylated polybenzimidazole arti bath, "wet jet/wet spinning', or through an air gap into cles. the coagulation bath, "dry jet/wet spinning". U.S. Pat. No. 3,518,234 discloses N-aryl substituted Typical dry spinning procedures are disclosed in U.S. polybenzimidazole polymers but, again, fails to disclose Pat. Nos. 3,584,104 and 3,502,756 while typical wet hydroxyethylated polybenzimidazole polymers or a spinning processes are disclosed in U.S. Pat. Nos. 45 process for the production of hydroxyethylated poly 4,512,894, 4,263,245, 3,851,025, 3,619,453, 3,526,693 and benzimidazole articles. 3,441,640. While the processes and the products pro Accordingly, it is an object of the present invention duced by these processes vary based on such differences to prepare hydroxyethylated polybenzimidazole fibers. as the composition of the coagulating bath, the denier of It is a further object of this invention is to prepare the spun fiber, or the structure of the fiber, none of these 50 hydroxyethylated polybenzimidazole fibers that exhibit patents discloses a method for spinning fibers formed a high degree of chemical and thermal stability. from substituted polybenzimidazole polymers, in gen It is a further object of this invention to prepare hy eral, or hydroxyethylated polybenzimidazole polymers, droxyethylated polybenzimidazole ultra filters which in particular. can filter a broad range of molecular weight com While processes for the production of substituted 55 pounds. polybenzimidazole fibers have not been disclosed, sev These and other objects, as well as the scope, nature, eral processes for the production of substituted poly and utilization of the process will be apparent from the benzimidazole polymers have been disclosed. For ex following description and the appended claims. ample, U.S. Pat. No. 3,578,644 discloses a process for the production of an hydroxyl modified polyben 60 SUMMARY OF INVENTION zimidazole polymer produced by reacting a polyben In accordance with the present invention there is Zimidazole polymer with an omega-halo-alkanol or a provided an hydroxyethylated polybenzimidazole fiber 1,2-alkylene oxide in the presence of a basic catalyst which is prepared by the following process: such as sodium hydride. However, this reaction process a forming a solution of a polybenzimidazole poly results in the formation of undesirable organic salts as a 65 mer; by-product; requires a pressurized vessel for the reac b. reacting the polybenzimidazole polymer with an tion; and the types of polybenzimidazole polymers ethylene carbonate to form an hydroxyethylated poly which can be used in this reaction are limited. For ex benzimidazole polymer solution; 4,814,228 3 4. c. extruding the hydroxyethylated polybenzimidazole -continued polymer solution through a spinneret; and N N d. coagulating the hydroxyethylated polyben 2 N / N zimidazole polymer solution in a coagulation bath to C R Carl form hydroxyethylated polybenzimidazole fibers. 5 N / N / The fibers produced by this process can be utilized as H H separatory media for such uses as ultra filters which exhibit a broad range of molecular weight cut offs. Such polybenzimidazoles are produced by the reac They may also be used for the production of high O tion of a mixture of (1) at least one aromatic tetraamine strength, chemically resistant, separatory articles where containing two groups of amine substituents, the amine the relatively large micropore size of the articles would substituents in each group being in an ortho position be useful. relative to each other, and (2) at least one dicarboxylate ester in which R1 and R2 in the compounds shown are DETAILED DESCRIPTION OF INVENTION 5 substituents selected from aliphatic, alicyclic and aro A. The Starting Material matic groups. Examples of polybenzimidazoles which have the The polybenzimidazole starting materials are a recurring structure of Formula I include: known class of heterocyclic polymers which are char poly-2,2'-(m-phenylene)-5,5'-bibenzimidazole; acterized by a recurring monomer unit which corre poly-2,2'-(pyridylene-3',5')-5,5'-bibenzimidazole; sponds to the following Formula I or II. Formula I is: poly-2,2'-(furylene-2',5')-5,5'-bibenzimidazole; poly-2,2'-(naphthalene-i",6")-5,5'-bibenzimidazole; poly-2,2'-(bihenylene-4",4")-5,5'-bibenzimidazole; N. N. a N / N 25 poly-2,2'-amylene-5,5'-bibenzimidazole; C R C A. poly-2,2'-octamethylene-5,5'-bibenzimidazole; N / N / poly-2,6'-(m-phenylene)-diimidazobenzene; N N poly-2,2'-(m-phenylene)-5,5-di(benzimidazole)ether; H H poly-2,2'-(m-phenylene)-5,5-di(benzimidazole)sulfide; 30 poly-2,2'-(m-phenylene)-5,5'-di(benzimidazole)sulfone; where R is a tetravalent aromatic nucleus with the ni poly-2,2'-(m-phenylene)-5,5-di(benzimidazole)me trogen atoms forming the benzimidazole rings being thane; poly-2,2'-(m-phenylene)-5',5'-di(benzimidazole)-pro paired upon adjacent carbon atoms, i.e., ortho carbon pane-2,2; and atoms, of the aromatic nucleus, and R is a divalent 35 poly-2,2'-(m-phenylene)-5',5'-di(benzimidazole)-ethy substituent selected from aliphatic, alicyclic and aro lene-1,2. matic radicals. Illustrative of R' substituents are diva The preferred polybenzimidazole of Formula I is lent organic radicals containing from about 2 to about poly-2,2'-(m-phenylene)-5,5'-bibenzimidazole as charac 20 carbon atoms, such as ethylene, propylene, butylene, terized by the recurring monomeric unit: cyclohexylene, phenylene, pyridine, pyrazine, furan, thiophene, pyran, and the like.