Europâisches Patentamt 0 033 906 ® ê European Patent Office (ÏÏ) Publication number: B1 Office européen des brevets ® EUROPEAN PATENT SPECIFICATION (§) Dateof publication of patent spécification: 15.05.85 © mtci.4: C 08 G 75/02, C 08 G 75/20 (B) Application number: 81100628.7 ® Date offiling: 28.01.81 (54) Process for the production of aromatic suif ide/sulfone polymers. (§) Priority: 29.01.80 US 116434 (73) Proprietor: PHILLIPS PETROLEUM COMPANY 5th and Keeler Bartlesville Oklahoma 74004 (US) (43) Date of publication of application: 19.08.81 Bulletin 81/33 (72) Inventor: Campbell, Robert Wayne 1330 S.E. Cherokee Hills Ct. (S) Publication of the grant of the patent: Bartlesville Oklahoma (US) 15.05.85 Bulletin 85/20 (74) Représentative: Dost, Wolfgang, Dr.rer.nat., (H) Designated Contracting States: Dipl.-Chem. et al BEDE GB Patent- und Rechtsanwàlte Bardehle- Pagenberg-Dost-Altenburg & Partner Postfach 86 06 20 Références cited: D-8000 Mùnchen 86 (DE) DE-A-2441 105 US-A-4016145 US-A-4070 349 US-A-4 089 847 ûû US-A-4 127 713 CD o co Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall CL be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been LU paid. (Art. 99(1 ) European patent convention). Courier Press, Leamington Spa, England. This invention relates to the production of aromatic sulfide/sulfone polymers exhibiting improved physical properties including improved melt flow stability. In recent years, a wide variety of high polymers including aromatic sulfide/sulfone polymers have been prepared. While such polymers are useful in many areas, one property of high polymer, particularly those of the thermoplastic type which needs to be improved, is the ability to withstand the high temperatures encountered in injection molding processes for an extended period of time. Since thermoplastic materials can be molded rapidly and efficiently into almost any desired shape, they lend themselves to mass production. A high polymer, especially a thermoplastic material which would stand high temperatures for an extended period of time without becoming unmanageably viscous exhibit desirable melt flow stability properties and could be used in such areas as electrical components, wire coatings and automotive parts, has been the objective of a great deal of research. It is known from US-A-4016145 to produce high molecular weight aromatic sulfide/sulfone polymers by subjecting to polymerization a mixture comprising (1) at least one dihaloaromatic sulfone, (2) at least one alkali metal sulfide, (3) at least one organic amide liquid at the reaction temperature and, optionally, (4) an alkali metal carboxylate and (5) an alkali metal hydroxide. However, as stated hereinbefore, it is desirable to improve the melt flow stability of the polymers so as to make them better suitable for injection molding. Accordingly, the invention relates to a process for the production of aromatic sulfide/sulfone polymers by subjecting to polymerization at a given polymerization temperature and pressure a mixture comprising (1) at least one dihaloaromatic sulfone, (2) at least one alkali metal sulfide, (3) at least one organic amide as solvent and, optionally, (4) an alkali metal carboxylate and (5) an alklai metal hydroxide, which process is characterized by adding to the reaction mixture at a time from 1.5 to 6 hours after said polymerization temperature is reached a dihaloaromatic sulfone (6) as end-capping agent in an amount from 0.01 : 1 to 0.2 : 1 moles per mole of alkali metal sulfide (2) and maintaining said polymerization temperature and pressure for a time of 1 minute to 5 hours after the addition of said haloaromatic sulfone end-capping agent (6). In accordance with this invention, the addition at, or near, completion of the polymerization reaction, of the end-capping dihaloaromatic sulfone (6) to the reaction mixture results in an aromatic sulfide/sulfone polymer of improved melt flow stability compared to prior art polymers. In one embodiment of the present invention, the dihaloaromatic sulfone (6), added as an end-capping agent, is the same as the dihaloaromatic sulfone (1) initially used as reactant. In another embodiment of the invention, the end-capping dihaloaromatic sulfone (6) which, preferably, is the same as the initial dihaloaromatic sulfone (1), and a solvent, preferably an organic amide corresponding to the organic amide (3) initially used for preparation of the polymer is introduced into the reaction mixture at, or near, completion of the polymerization reaction. The polymers of this invention are amorphous with a high glass transition temperature (Tg). They exhibit physical properties and melt flow characteristics suitable for injection moldable, high performance thermoplastics. Dihaloaromatic sulfones that can be employed in the process of the invention have the formula where each X is selected from fluorine, chlorine, bromine, and iodine; Z is a divalent radical selected from n is 0 or 1; A is selected from sulfur, sulfonyl, and CR2; and each R is selected from hydrogen and alkyl radicals having 1 to 4 carbon atoms, the total number of carbon atoms in all of the R groups in the molecule being 0 to 12. Preferably, each n is 0. Bis(p-halophenyl) sulfones are preferred reactants in the process of this invention and can be represented by the formula where each X is selected from fluorine, chlorine, bromine, and iodine, and each R is selected from hydrogen and alkyl radicals having 1 to 4 carbon atoms, the total number of carbon atoms in each molecule being within the range of 12 to 24. Examples of some dihaloaromatic sulfones that can be employed in the process of this invention include bis(p-fluorophenyl) sulfone, bis(p-chlorophenyl) sulfone, bis(p-bromophenyl) sulfone, bis(p-iodo- phenyl) sulfone, p-chlorophenyl p-bromophenyl sulfone, p-iodophenyl 3-methyl-4-fluorophenyl sulfone, bis(2-methyl-4-chlorophenyl) sulfone, bis(2,5-diethyl-4-bromophenyl) sulfone, bis(3-isopropyl-4- iodophenyl) sulfone, bis(2,5-dipropyl-4-chlorophenyl) sulfone, bis(2-butyl-4-fluorophenyl) sulfone, bis(2,3,5,6-tetramethyl-4-chlorophenyl) sulfone, 2-isobutyl-4-chlorophenyl 3-butyl-4-bromphenyl sulfone, 1,4-bis(p-chiorophenyisuifonyi)benzene, 1-methyl-2,4-bis(p-fluorophenylsulfonyl)benzene, 2,6-bis(p- bromophenylsulfonyl)naphthalene, 7-ethyl-1,5-bis(p-iodophenylsulfonyl)naphthalene, 4,4'-bis(p- chlorophenyl-sulfonyl)biphenyl, bis[p-(p-chlorophenylsulfonyl)phenyl] sulfide, bis[p-(p-chloro- phenylsulfonyl)phenyl] sulfone, bis-[p-(p-bromophenylsulfonyl)phenyl]methane, and 5,5-bis[3-ethyl-4-(p- chlorophenylsulfonyl)phenyl]nonane, and mixtures thereof. Bis(p-chlorophenyl) sulfone is preferred. Alkali metal sulfides that can be employed in the process of this invention include sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures thereof. The alkali metal sulfide can be used in anhydrous form, as a hydrate, or as an aqueous mixture. Sodium sulfide is especially preferred. As is well known in the prior art for the preparation of aromatic sulfide/sulfone polymers or aromatic sulfide polymers, precursors of alkali metal sulfides can be employed in place of the alkali metal sulfide. For example, a combination of alkali metal bisulfide and alkali metal hydroxide known to react to form alkali meta! sulfide and water can be employed. The organic amides used in the method of this invention should be substantially liquid at the reaction temperatures and pressures employed. The amides can be cyclic or acyclic and can have 1 to 10 carbon atoms per molecule. Examples of some suitable amides include formamide, acetamide, N-methyl- formamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-ethylpropionamide, N,N-dipropyl- butyramide, 2-pyrrolidone, N-methyl-2-pyrrolidone, e-caprolactam, N-methyl-e-caprolactam, N,N'- ethylenedi-2-pyrrolidone, hexamethylphosphoramide and tetramethylurea, and mixtures thereof. N- methyl-2-pyrrolidone is especially preferred. Small amounts of strong base, e.g., alkali metal hydroxide, can also be employed, if desired, with the other ingredients in the polymerization step of this invention. The dihaloaromatic sulfones (6) added to the reaction mixture as end-capping agents at or near completion of the polymerization reaction can be the same as (preferred) or different from (non-preferred) the dihaloaromatic sulfone (1) employed as initial reactant in the process. The sulfones added subsequent to the initial reactants will be selected from those corresponding to the above generic formula. Bis(p- chlorophenyl) sulfone is preferred. If desired, an alkali metal carboxylate can be employed with the initial ingredients of the above- described polymerization process. Usage of an alkali metal carboxylate generally results in an aromatic sulfide/sulfone polymer of higher molecular weight (as evidenced by higher inherent viscosity) than polymers prepared in the absence of alkali metal carboxylate. Alkali metal carboxylates that can be employed in the process of this invention can be represented by the formula R'C02M, where R' is a hydrocarbyl radical selected from alkyl, cycloalkyl, and aryl, and combinations thereof such as alkaryl and aralkyl, the number of carbon atoms in said R' being within the range of 1 to 20, and M is an alkali metal selected from the group consisting of lithium, sodium, potassium,