Abstract: The present invention provides an improvement in a process for preparing polyimide compositions from a mixture of monomers by the application of heat in two stages. The improvement comprises incorporating a cyclic peroxyketal catalyst, such as 3,6,6,9,9,-pentamethyl-3-(ethylacetate)-1,2,4,5-tetraoxycyclononane, into the monomer mixture prior to reaction.
Abstract: A novel polyester is provided which has been found to exhibit an optically anisotropic melt phase at a temperature which enables it readily to undergo melt processing to form quality molded articles, etc. The polyester of the present invention is formed primarily of recurring 6-oxy-2-naphthoyl and m-oxybenzoyl moieties in the proportions indicated. The hydrogen atoms present upon the aromatic rings of these moieties optionally may be at least partially substituted (as described). Also, minor amounts of other ester-forming moieties may be included in the polyester so long as the optically anisotropic character in the melt and ease of melt processability are retained. In a preferred embodiment the wholly aromatic polyester is capable of undergoing melt processing at a temperature below approximately 370.degree. C., and in a particularly preferred embodiment at a temperature of approximately 280.degree. to 320.degree. C.
Abstract: A novel polyester is provided which has been found to exhibit an anisotropic melt phase at a temperature which enables it readily to undergo melt processing to form quality fibers, molded articles, etc. The polyester of the present invention includes as essential ingredients moieties derived from para-hydroxy benzoic acid, 2,6-naphthalene dicarboxylic acid, terephthalic acid, and methylhydroquinone in the proportions indicated. In a preferred embodiment the polyester is capable of undergoing melt processing at a temperature below approximately 320.degree. C., and in a particularly preferred embodiment at a temperature below approximately 300.degree. C. (e.g., with standard equipment commonly used to melt process polyethylene terephthalate). Fibers conveniently can be melt spun from the polyester of the present invention which exhibit tenacity values which are enchanced upon thermal treatment.
Abstract: The present invention provides an improved process for extruding liquid crystal polymer. The process comprises the steps of providing a fluid stream of liquid crystal polymer wherein the stream has a flow pattern comprising substantial shear flow; converting the flow of the fluid stream of liquid crystal polymer to a substantially elongational flow in the substantial absence of shear flow; and extruding the fluid stream of liquid crystal polymer to form a shaped article having the polymer molecules oriented substantially parallel to the flow direction. The resulting articles are self-reinforcing, having mechanical properties superior to conventional extruded liquid crystal polymer articles and comparable to those of articles formed from fiber-reinforced isotropic polymeric materials.
Abstract: A process for preparing fine powder particles of thermoplastic elastomer polymer is disclosed. This process comprises suspending thermoplastic elastomer solids in a poor solvent for the polymer using mild agitation and then admixing this suspension with a non-solvent for the polymer in the presence of high shear mixing. Powder particles having an average diameter of less than about 100 microns are obtained.
Type:
Grant
Filed:
October 28, 1980
Date of Patent:
May 18, 1982
Assignee:
Celanese Corporation
Inventors:
Martin J. Hannon, Rajal M. Vyas, Rudolph R. Schwarz
Abstract: This invention provides a process for producing a carboxylate ester from a monoolefin and a carboxylic acid, in the presence of a solid catalyst comprising a composite of 5-sulfoisophthalic acid and a carrier substrate having a surface area between about 1-1000 m.sup.2 /gram.A carboxylate ester such as ethyl propionate is produced with a STY efficiency of at least 100 grams/liter hour.
Abstract: A melt processable poly(ester-amide) which is capable of forming an anisotropic melt phase is provided. The poly(ester-amide) of the present invention consists essentially of the recurring units (a) 6-oxy-2-naphthoyl moiety, (b) aryl dicarboxyl moiety or trans-1,4-dicarboxycyclohexane moiety, (c) an aromatic moiety capable of forming an amide linkage in the polymer, and (d) optionally, dioxyaryl moiety in the proportions indicated. Preferably, the aromatic moiety capable of forming an amide linkage is p-aminophenol or p-phenylenediamine. The resulting poly(ester-amide) exhibits a melting temperature below approximately 400.degree. C., preferably below approximately 350.degree. C. The poly(ester-amide) of the present invention is preferably formed by a melt polymerization technique.
Type:
Grant
Filed:
December 9, 1980
Date of Patent:
May 18, 1982
Assignee:
Celanese Corporation
Inventors:
Anthony J. East, Larry F. Charbonneau, Gordon W. Calundann
Abstract: A process for the extrusion of melt processable liquid crystal polymer which provides improved processability characteristics is provided. The process comprises the steps of subjecting the liquid crystal polymer to an elevated temperature between the DSC transition temperature and the degradation temperature of the polymer; cooling the liquid crystal polymer to a processing temperature which is between the DSC transition temperature and the elevated temperature and at which the liquid crystal polymer is less subject to degradation than at the elevated temperature; and extruding the liquid crystal polymer into the form of a shaped article having mechanical properties which are improved over those of articles formed from liquid crystal polymer which has not been subjected to the elevated temperature.
Abstract: Halogenated aromatic polyesters having the recurring structural formula ##STR1## wherein X is chlorine or bromine and Y is hydrogen, chlorine or bromine, with the provision that when X is chlorine, Y is hydrogen or chlorine and when X is bromine, Y is hydrogen or bromine, R and R' may be the same or different and represent lower alkyl groups, hydrogen, or together constitute a cyclic hydrocarbon group, and n is an integer which is at least about 10, are prepared by(a) reacting in solution in the presence of an excess amount of a tertiary amine(1) a bisphenol having the structural formula ##STR2## wherein X, Y, R and R' have the same meanings as given above; with (2) an aromatic acid halide selected from the group consisting of terephthaloyl halide, isophthaloyl halide, and mixtures thereof to form a reaction mixture comprising solvent, tertiary amine hydrochloride, unreacted tertiary amine, and the halogenated aromatic polyester,(b) adding to the reaction mixture an amount of gaseous, substantially anhydrous,
Abstract: An improved solution of a polybenzimidazole suitable for use in the formation of shaped articles (e.g. fibers, films, and the like) is provided which includes a minor amount of an organo-lithium compound (as defined) which has been found to be capable of inhibiting the separation of the solution into phases of greater and lesser concentrations of the polybenzimidazole upon the passage of time. In a preferred embodiment the organo-lithium compound is lithium stearate. Not only is stability imparted to the solution prior to the formation of a shaped article, but the potential for catastrophic corrosive stress cracking of stainless steel equipment in contact with the solution is eliminated such as that which may occur following the extended use of the common prior art additive, lithium chloride.
Type:
Grant
Filed:
May 4, 1981
Date of Patent:
March 23, 1982
Assignee:
Celanese Corporation
Inventors:
Robert Davitt, Gordon W. Calundann, Edward C. Chenevey
Abstract: A novel thermotropic polyester is provided which has been found to exhibit an optically anisotropic melt phase at a temperature which enables it readily to undergo melt processing to form quality molded articles, fibers, etc., which exhibit substantial flexibility. For instance, molded articles can be prepared having an unusually high impact strength, toughness, and high extension in addition to other highly satisfactory mechanical properties. The polyester of the present invention contains recurring 6-oxy-2-naphthoyl and p-oxybenzoyl moieties in addition to terephthaloyl moieties and meta-dioxyphenylene moieties in the proportions indicated. Such meta-dioxyphenylene moieties are non-symmetrical in structure. The hydrogen atoms present upon the aromatic rings of these moieties optionally may be at least partially substituted (as described). The wholly aromatic polyester is capable of forming the desired optically anisotropic melt at a temperature below approximately 350.degree. C.
Abstract: A novel polyester is provided which has been found to exhibit an optically anisotropic melt phase which enables it readily to undergo melt processing to form quality fibers, films, molded articles, etc. The polyester of the present invention contains recurring 6-oxy-2-naphthoyl moieties in addition to moieties derived from at least one aromatic diol and trans-1,4-cyclohexanedicarboxylic acid in the proportions indicated. The hydrogen atoms present upon the rings of these moieties optionally may be at least partially substituted (as described). The polyester is capable of forming the desired anisotropic melt at a temperature below approximately 350.degree. C., and in a particularly preferred embodiment at a temperature below approximately 320.degree. C.
Abstract: A process for the production of high molecular weight oxymethylene copolymer in the presence of impurity is provided. The process provides a high molecular weight oxymethylene copolymer having a predetermined comonomer content. The process comprises the steps of determining the optimal catalyst concentration in a first oxymethylene copolymerization system which contains less than approximately 10 p.p.m. impurity; determining the concentration of impurity containing at least one active proton in a second copolymerization system; adjusting the catalyst concentration in the second copolymerization system so that the total concentration of catalyst and impurity in the second copolymerization system is maintained at the optimal concentration of catalyst in the first copolymerization system; and adjusting the concentration of comonomer in the second copolymerization system so as to maintain the predetermined comonomer content in the oxymethylene copolymer product.
Abstract: A single-stage melt polymerization process for the production of high molecular weight polybenzimidazole is provided. The process comprises reacting a monomeric reactant or reactants, which are capable of reacting to form a polybenzimidazole, at a temperature above the melting temperature of the monomeric reactant or reactants in the presence of a catalyst selected from the group consisting of organic sulfonic acids, halogenated acetic acids, and non-oxidizing inorganic acids. The polybenzimidazole is preferably produced by the reaction of 3,3',4,4'-tetraaminobiphenyl with isophthalic acid at a temperature within the range of approximately 360.degree. C. to 425.degree. C. for a period of time within the range of approximately 3 to 5 hours in the presence of approximately 0.25 to 0.5 percent by weight, based upon the weight of the isophthalic acid, of p-toluenesulfonic acid.
Abstract: An improved apparatus for cutting material such as filamentary tows into predetermined lengths comprising (a) a cutting assembly including a plurality of spaced apart knife edges secured to a mounting member at equal radial distances from a point on said mounting member thereby forming a reel, each of said radial distances in every instance being less than the distance from said point to the periphery of said mounting member; (b) said cutting assembly having means adapted to receive successive wrappings of material to be cut in contact with a plurality of said knife edges so that no relative movement occurs between said material and said knife edges longitudinally of said material; and (c) means for forcing said material between adjacent knife edges thereby severing said material into lengths of controlled dimensions, wherein the improvement comprises: means for preventing at least most of said knives from moving in a direction longitudinal of said knife edges.
Abstract: An improved process is provided for the production of polymeric filamentary material or film. Molten melt-spinnable polymeric material capable of undergoing crystallization (e.g., a polyester) is extruded through a shaped orifice to form a filamentary material or film under high stress conditions, quenched to below its glass transition temperature to form a solid filamentary material or film, and sequentially passed for a brief residence time through a thermal conditioning zone at a temperature between its glass transition temperature and its melting temperature wherein the internal structure thereof is modified and substantial crystallization of the previously solidified filamentary material or film takes place. The filamentary material or film is withdrawn from the conditioning zone at a rate of 1000 to 6000 meters per minute while under a relatively high stress of about 0.1 to 1.0 gram per denier.
Type:
Grant
Filed:
September 26, 1973
Date of Patent:
March 23, 1976
Assignee:
Celanese Corporation
Inventors:
Herbert L. Davis, Michael L. Jaffee, Michael M. Besso