DE2721787A1 - IMPROVED FULLY AROMATIC THERMOTROPIC POLYESTERS, PROCESSABLE FROM THE MELT, AND THEIR USE FOR FIBER MANUFACTURING - Google Patents

Description

FROM KREISLER SCHONWALD MEYER EISHOLD FUES FROM KREISLER KELLER SELTING

PATENT LAWYERS

Dr.-Ing. by Kreisler ή- 1973

Dr.-Ing. K. Schönwald, Cologne

Dr.-Ing. Th. Meyer, Cologne

Dr.-Ing. K. W. Eishold, Bad Soden

Dr. J. F. Fues, Cologne

Dipl.-Chem. Alek von Kreisler, Cologne

Dipl -Chem. Carola Keller, Cologne

Dipl.-Ing. G. Selling, Cologne

Fu / Ax

5 COLOGNE l, May 13, 1977

DEICHMANNHAUS AT THE HAUPTDAHNHOF

CELANESE CORPORATION, Avenue of the Americas, New York, N.Y. 10036 (USA)

Improved Melt Processable Fully Aromatic Thermotropic Polyesters and Their Use for Fiber manufacture

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T |. t .-. n .02 211 23 .15-U -.! Telfx: 888 2307 dopa d Telrgromm Dompalent Cologne

Improved Melt Processable, Fully Aromatic Thermotropic Polyesters and Their Uses for fiber production

Fully aromatic polyester resins have long been known. For example, have already been the homopolymer and the copolymers of p-hydroxybenzoic acid produced and placed on the market. These usually Completely aromatic polyesters occurring in the prior art tend to be somewhat unformed and present substantial difficulties when attempting to melt them using conventional Process melt processing methods. These polymers are usually crystalline in nature, relatively high-melting or have a decomposition temperature below the melting point and often have an isotropic melt phase in the molten state. Shaping processes, e.g. pressing or sintering, are applicable to these materials, however injection molding, melt spinning, etc. usually not viable alternatives, or when tried, usually with difficulty perform. In general, these polymers cannot be broken down by melt spinning Fibers are processed. Even the fully aromatic polymers, the melting point of which is below their decomposition temperature, generally melt at such a high temperature Temperatures that high quality fibers cannot be produced by melt spinning. For example, have Fibers made by melt spinning at extremely high temperatures are generally porous

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Internal structure with voids and deteriorated strength properties.

Representative publications that describe fully aromatic polyesters include: a) Polyesters of Hydroxybenzenes Acids by Russell, Gilkey and John R. Caldwell, J. of Applied Polymer Sci., Vol. II (1959), pages 198-202, b) Polyarylates (Polyesters From Aromatic Dicarboxylic Acids and Bisphenols) by G. Bier, Polymer, Vol. 15 (August 1974), pages 527 to 535, c) Aromatic Polyester Plastics by SG Cottis, Modem Plastics, July 1975, pages 62 to 63, and d) Poly (p-Oxybenzoyl Systems): Homopolymer for Coatings: Copolymers for Compression and Injection Molding by Roger S. Storm and Steve G. Cottis, Coatings Plast.

Preprint, Vol. 34, No. 1 (April 1974), pages 194-197.

Reference is also made to US Patents 3039994, 3169121, 3321437, 3553167, 3637595, 3651014, 3723388, 3759870, 3767621, 3787370, 3790 528, 3 829 406, 3 890 256 and 3 975 487.

More recently it has been reported that certain polyesters exhibiting melt anisotropy can be made. For example, reference is made to a) Polyester X7G-A Self Reinforced Thermoplastic by WJJackson, Jr., HF Kuhfuss and TF Gray, Jr., 30th Anniversary Technical Conference 1975, Reinforced Plastics / Composites Institute, The Society of the Plastics Industry, Inc. , Section 17-D, pages 1 to 4, b) BE-PSen 828 935 and 828 936, c) NL-PS 7505551, d) DT-PSen 25 20 819 and 25 20 820, e) JA-PS 43-223 and f) U.S. Patents 3,991,013 and 3,991,014.

The invention relates to improved, fully aromatic polyesters which can be processed from the melt and which are free from

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Ring substitution and are particularly well suited for fiber production.

The invention is directed to improved melt-processable, aromatic polyesters that are easy to process at a temperature below about 300 ⁰ C, preferably 28O ° C are capable of forming a thermotropic melt phase even in the absence of ring substitution below about by melt extrusion and melt spinning leaves. These esters have a melting point well below their decomposition temperature and can be easily processed into high-quality fibers.

The invention also includes improved wholly aromatic polyester fibers (as defined above) which are high Have tear strength and high tensile modulus and retain these properties at elevated temperatures and at the same time have a very low tendency to shrinkage and good hydrolytic stability.

The DT-PS (patent application P

of the same day corresponding to US patent application 686 189 of May 13, 1976) of the applicant describes improved, Melt-processable, thermotropic, fully aromatic polyesters and a process for their production. These fully aromatic polyesters essentially consist of recurring units from one p-Oxybenzoyl building block, a 2,6-dicarboxynaphthalene building block and a symmetrical dioxyaryl building block.

It has been found that improved, melt-processable, fully aromatic polyesters that are capable of operating at temperatures Able to form a thermotropic melt phase below about 300 ° C, essentially from

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-VZ-

consist of the following recurring units I, II, III and IV:

II

III: a symmetrical dioxyaryl unit of the formula

- \ - 0 Ar - 0 - j -, in which Ar is a divalent radical

that has one or more fused or separate aromatic rings (i.e. at least contains an aromatic ring), and

IV recurring units of the formulas

-C

(b)

and mixtures of (a) and (b) wherein the polyesters are about 20 to 70 mole percent (e.g. about

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40 to 70 mol%) of unit I, about 3 to 30 mol% (e.g. about 7.5 to 30 mol%) of unit II, about 7.5 to 40 mol% (e.g. about 7.5 to 30 mol%) of unit III and about 4 to 30 mole percent (e.g., about 4 to 20 mole percent) of unit IV and each of these units the polyester is free of ring substitution.

Fibers made from the wholly aromatic polyesters according to the invention have one Heat treatment has relatively high tensile strength and tensile modulus values that they even at elevated temperatures to preserve.

Preferred embodiments of the invention are described below.

The wholly aromatic polyesters according to the invention consist essentially of at least four repeating ones Building blocks or units that, when combined in the polyester, result in polymers that are used for Melt spinning are particularly well suited for the production of fibers. The polymers are atypical thermotropic melt phase at a temperature below about 300 ° C, preferably below about 280 ° C. It was found that the melting temperature, which the fully aromatic polymer initially has after its formation, can be slightly above the relatively constant temperature at which it is later heated solid polymer melts. All melting temperatures given here mean accordingly, unless otherwise indicated these later stable melting temperatures which the non-tempered polyesters have. These stable melting temperature can be achieved by using a differential scanning calorimeter using Repetitive scans at a heating rate

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can be confirmed at a rate of 20 ° C / minute. Each unit of the Fully aromatic polyester is free of ring substitutions other than the linking bonds that form the main polymer chain form. These aromatic polyesters are crystalline in nature and, due to their ability to have ordered anisotropic properties (i.e. liquid crystals) in the melt, easily from the Melt are processed, with strongly oriented threads are obtained directly during spinning. The customary Difficulties encountered when attempting to isolate aromatic polyesters by conventional methods The melt process are effectively turned off. The melt extrusion temperature for the fully aromatic Polyester is unusually low. The aromatic polyesters become "wholly aromatic" in that sense considered that each unit or each building block present in them at least one aromatic ring to Polymer main chain contributes.

The fully aromatic polyesters essentially consist of at least four building blocks or units (as above Are defined). The unit I can be used as a p-oxybenzoyl unit and has the structural formula

The unit I makes up about 20 to 70 mol% or about 40 to 70 mol% of the fully aromatic polyesters (eg about 50 to 70 mol%), preferably 40 to 60 mol%, with about 60 mol% in one embodiment described below are particularly preferred.

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The second essential recurring unit (i.e. building block II) of the fully aromatic polyester is a 2,6-dicarboxynaphthalene unit of the structural formula

It is essential that the unit II consists of two fused benzene rings, as shown above, and not consists of a single divalent benzene ring. For example, it has been found that when considering individual benzene rings would replace a substantial portion of the naphthalene rings of Unit II, the properties of the wholly aromatic polyester obtained would be significantly different and adversely affected than the essentially show higher flow and melting temperatures which lead to severe degradation during processing. in the generally the unit II makes about 3 to 30 mol% or about 7.5 to 30 mol%, preferably about 3 to 15 mol% or about 10 to 20 mole percent of the wholly aromatic polyester.

The third critically important recurring unit (i.e. unit III) is the fully aromatic polyester a symmetrical dioxyaryl unit of the formula

-Uo Ar 0-J-, where Ar is a divalent radical,

the one or more fused or separate aromatic rings (i.e. at least one aromatic ring) contains. The unit III is symmetrical in the sense that the divalent bonds that the unit has with others Connecting units in the main polymer chain, arranged symmetrically on one or more aromatic rings are (e.g. in p-position to each other or diagonally

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arranged if they are present on a naphthalene ring). In general, the unit III makes about 7.5 to 40 mole percent or about 7.5 to 30 mole percent, preferably about 15 to 30 mole percent (e.g., about 15 to 20 mole percent) or about 20 to 30 mole percent of the wholly aromatic polyester. as Examples of preferred building blocks which are used as a symmetrical dioxyaryl unit in the fully aromatic polyesters according to can serve the invention, may be mentioned:

O-

\ J

-O-

—T — ο -

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and mixtures of these units.

The unit of the formula is particularly preferred as unit III

Γ "

The fourth crucial unit (i.e. building block IV) of the fully aromatic polyester is made up of the

(a)

—-Ο

.-O

and mixtures of the group consisting of (a) and (b). Unit IV is of a non-symmetrical nature.

The unit (a) can be referred to as an isophthaloyl unit and can be derived from isophthalic acid. From the For reasons already mentioned, the terephthaloyl unit is excluded, since it has been shown that such a unit adversely affects the properties, as shown by an increased melting temperature, which makes it difficult to process the polymer obtained from the melt without undesired degradation of the polymer. The unit (b) may be an m-dioxyphenyl unit and be derived from resorcinol. In general, unit IV makes about 4 up to 30 mol% or about 4 to 20 mol% of the wholly aromatic Polyester, preferably about 5 to 10 mol% or about 10 to 27 mol%. When unit (b) is chosen, it is generally used at a lower concentration than if unit (a) had been chosen.

In addition to the above-mentioned ester-forming units, other ester-forming units (e.g. dicarboxy-

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or dioxy units), which are free from ring substitution, in addition to the fully aromatic polyesters according to the invention can be incorporated in low concentration (e.g. up to about 10 mol%) as long as these units have the desired thermotropic melt phase, which have the polyester according to the invention, do not adversely affect or the Increase the melting point of the polymer above about 300.degree. As will be understood by those skilled in the art, all are molar Amounts of the dicarboxylic acid units and dioxy units that are present in the fully aromatic polyesters, essentially the same. The various units tend to be present in a random manner after the polymer has formed.

The wholly aromatic polyesters according to the invention generally contain, depending on the synthetic route chosen terminal groups of the formula

0 0

Il «

- 0 C CH ₃ or --COH

As is known to those skilled in the art, the terminal groups can optionally be blocked. For example can have acidic end groups with different alcohols and terminal hydroxyl groups with different organic ones Acids are blocked. For example, stabilizing units, e.g. the phenyl ester

Λ), and the methyl ester (—C — 0 — CH ₃ )

be incorporated into the end of the polymer chains. The polymer can also, if appropriate, at least up to one be oxidatively crosslinked to a certain extent by being in an oxygen-containing atmosphere (e.g. in air) in the unformed State or as a previously produced molded part to a temperature below its melting point during is heated for a limited time (e.g. a few minutes).

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The fully aromatic polyesters according to the invention are essentially insoluble in all common solvents for polyesters, for example hexafluoroisopropanol and o-chlorophenol, so that they are generally not suitable for processing from solutions. As will be described in detail later, they can surprisingly easily be processed from the melt by conventional methods and are particularly suitable for the production of fibers by melt spinning. The polymers are soluble in all common in pentafluorophenol.

The wholly aromatic polyesters generally have a weight average molecular weight of from about 2,0OO to 200,000, preferably from about 10,000 to 25,000, e.g., about 20,000 to 22,000. This molecular weight can be simply by conventional methods in which the polymer is not dissolved (e.g. by determining the end groups with the aid of infrared spectroscopy on foils produced by pressing), or by testing a solution of the polymer can be determined in pentafluorophenol by light scattering methods.

The fully aromatic polyesters also usually have an inherent viscosity (IV) of about 0.5 to 7, preferably from 2 to 3.3, in particular from 2.5 to 3.1, if they are in a concentration of:
solves are.

tration of 0.1 wt .-% in pentafluorophenol at 60 ° C ge

The wholly aromatic polyester according to the invention, as are crystalline referred to in the sense that fibers which have been produced by melt spinning from, filtered Ni when using CuK ^ .- radiation and cameras with flat plates X-ray diffraction images, the crystalline for polymeric materials characteristic are, and if they are heated, a sharp Schmelzpunkts-

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endothermic and when in a differential scanning calorimeter are cooled, exhibit a crystallization exotherm.

In contrast to the usual aromatic polyesters of the prior art, the fully aromatic polyesters according to the invention malleable and processable and form a thermotropic melt phase, creating an atypical Shows degree of order in the molten polymer. These polyesters easily form liquid crystals in the Melt phase and therefore show a strong tendency of the polymer chains to orient themselves in the shear direction. These thermotropic properties are unusual low temperature, so that the polymers to a large extent melt spinning for the production of Fibers are accessible. This anisotropy in the melt can be achieved by conventional methods with polarized light Use of crossed polaroids to be confirmed. In detail, the thermotropic melt phase can be in a simple Way by using a Leitz polarizing microscope at 4X magnification, with the sample on a heated Leitz microscope slide is under a nitrogen atmosphere. The polymer melt is optically anisotropic, i.e. translucent, when examined between crossed polaroids.

The amount of light transmitted increases when the Sample is sheared (i.e. made to flow). However, the sample is optically anisotropic even in a static state. On the contrary, typical aromatic polyesters are not substantially translucent when under under the same conditions.

The fully aromatic polyesters according to the invention can be produced by various ester formation processes, in which organic monomer compounds that contain functional groups that cause the condensation

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- IA -

necessary recurring units are implemented. For example, the functional groups of the organic monomer compounds can be carboxylic acid groups, hydroxyl groups, ester groups, acid halides, and so on. For example, the organic monomer compounds can be reacted in the absence of a heat exchange medium. Accordingly, they can be heated using a solid-phase condensation process in which the naphthalenedicarboxylic acid is present at least initially as a solid, the temperature gradually increasing until it exceeds the melting point of the polymer, whereupon the reaction occurs as a condensation process in the melt is continued. To remove volatile substances that are formed during condensation (e.g. acetic acid and water) to facilitate, vacuum can be applied. It can also start in a suspension system (slurry system), whereby the reaction is completed in the melt.

As an alternative, the DT-PS (patent

message P from the same day accordingly

US patent application 686 189) of the applicant discloses a suspension polymerization process (slurry polymerization process) that can be used to create the fully aromatic Forming polyester according to the invention. In this process, the product takes as it is formed, the form of small agglomerates of individual particles, as shown in Fig. 1 and Fig. 2 of the aforementioned application are shown.

In such a process, the details are organized monomeric reactants making up the p-oxybenzoyl unit (i.e. the unit I) and the symmetrical Dioxyaryl unit (i.e. the unit III) are derived, presented at the beginning in a modified form, whereby the usual hydroxyl groups of these monomers are esterified

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(i.e. they are presented as acyl esters). For example, lower acyl esters of p-hydroxybenzoic acid, wherein the hydroxyl group is esterified and lower acyl diesters of aryl diols are used as reactants. The lower acyl radicals preferably contain 2 to about 4 carbon atoms. Preferably the acetate esters are organic Compounds forming units I, III and IV (b) are used. Accordingly, p-acetoxybenzoic acid, Hydroquinone diacetate and isophthalic acid and / or m-phenylene diacetate as reactants for the condensation with 2,6-naphthalenedicarboxylic acid are particularly preferred. if (as already mentioned) other aryl reactants in small amounts, optionally oxy units in the polymer obtained form, these are also preferably used as corresponding lower acyl esters.

The quantitative ratio of the organic monomeric reactants is adjusted in the reaction zone so that the potential dicarboxy units and dioxy units, which are available for incorporation into the resulting wholly aromatic polyester are essentially the same.

In the suspension polymerization process, the Reaction participants (e.g. p-acetoxybenzoic acid, 2,6-naphthalenedicarboxylic acid, Hydroquinone diacetate and isophthalic acid and / or m-phenylene diacetate) in an inert heat exchange medium submitted, which preferably serves as a solvent for at least one of the reactants. Typically, the 2,6-naphthalenedicarboxylic acid employed is essentially insoluble in the inert heat exchange medium and present therein as a finely divided solid.

While the polymer is being formed, it is insoluble in the inert heat exchange medium and takes the form of a fine powder that has already been marked. The heat exchange medium preferably has a boiling point the above the applied maximum polymerization temperature

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^27217δ7

door lies. Inert heat exchange media are particularly preferred with boiling ranges from about 350 to 400 ° C. Representative heat exchange media are the terphenyls, a eutectic mixture of 73.5% diphenyl oxide and 26.5% diphenyl (manufacturer Dow Chemical Co., trade name "Dowtherm A"), and mixtures of polychlorinated polyphenyls, e.g. chlorinated biphenyls, as they are commercially available under the name "Therminol FR" (manufacturer Monsanto Co.), terphenyls and their mixtures, e.g.

Mixtures of the m- and p-isomers under the name "Therminol" are commercially available (e.g. Therminol 88, 77 or 66) (manufacturer Monsanto Co.), Diphenyl sulfone, other aryl sulfones, e.g. substituted Diphenyl sulfones (e.g. ditolyl sulfone) etc. The weight ratio of the inert heat exchange medium to all of the reactants in the reaction zone is in generally at about 0.2: 1 to 4: 1, preferably at about 2: 1.

The slurry polymerization reaction can be carried out batchwise, continuously or semi-continuously. Typical polymerization reactions are generally carried out at a temperature of at least about 200 C up to a temperature Temperature below the melting temperature or decomposition temperature of the fully aromatic polyester formed is carried out, for example at about 2OO ° to 275 ° C.

In a preferred embodiment of the slurry process the temperature of the slurry is increased as the polymerization reaction proceeds. It has been shown that a gradual or gradual increase in temperature during polymerization results in the formation of a superior product guaranteed. The polymerization is preferably carried out with agitation at normal pressure under an inert gas, while the by-products of the condensation reaction (e.g. acetic acid) continuously exit the reaction zone can be withdrawn, overpressure or reduced pressure

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may be used, but generally without reasonable benefit. The reaction times are generally in the range of about 2 to 30 hours or more, the shorter reaction times being possible if the reaction is catalyzed.

Representative examples of catalysts for the process are dialkyltin oxide (e.g. dibutyltin oxide), Diaryl tin oxide, titanium dioxide, alkoxy titanium silicates, titanium alkoxides, the gaseous acid catalysts, e.g. Lewis acids, Hydrohalides (e.g. HCl), alkali and alkaline earth salts of carboxylic acids (e.g. sodium acetate) should be mentioned. The amount of catalyst used is generally about 0.001 to 1% by weight based on the total weight of the monomers, preferably about 0.01 to 0.2% by weight.

After the polymerization reaction has ended, the solid, finely divided, fully aromatic polyester (as above defined) isolated by any suitable method. For example, the solid, finely divided polymer can be simple from the inert heat exchange medium (preferably after cooling) by decanting, centrifuging or filtration be separated. It is then washed and dried. During washing, residual heat exchange medium, that sticks to the product, with acetone, alcohols, lower hydrocarbons, methylene chloride, chloroform, benzene, Toluene, etc., or any other relatively volatile solvent in which the heat exchange medium is soluble, can be removed.

For the production of fibers and foils, the extrusion die can be made from the ones usually used for melt extrusion Moldings used nozzles are selected. For example, the extrusion die for producing a film have the shape of a rectangular slot. If thread

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materials are produced, the selected spinning nozzle can have a bore, but a plurality of bores is preferred. For example , a conventional conical spinneret with 1 to 200 bores (e.g. , 6 to 200 bores), as is commonly used for melt spinning polyethylene terephthalate, can be used with a diameter of the bores of about 5 to 60 mils, e.g. 10 to 40 mils. Generally , yarns are formed from about 20 to 36 filaments. The melt-spinnable, fully aromatic polyesters are fed to the extrusion or spinning nozzle at a temperature above their melting point, for example at a temperature of about 280 ° to 300 ° C.
After extrusion or after spinning through the nozzles , the thread materials or films formed are guided in the longitudinal direction through a solidification or quenching zone in which the melted thread material or the melted film is converted into solid thread material or solid films. The threads obtained in this way generally have an individual denier of about 2 to 50, preferably about 2 to 20, den.

The thread materials or foils obtained can optionally be subjected to a heat treatment , by means of which their physical properties are further improved . In particular, the tear strength or tensile strength of the fibers or films is increased by this heat treatment . In particular, the fibers or films can be subjected to heat treatment in an oxygen-containing atmosphere (e.g. air) or in an inert atmosphere (e.g. nitrogen, argon or helium) with or without tension at a temperature below the melting point of the polymer until the desired improvement in properties is achieved is. The atmosphere in which the heat treatment is carried out is preferably flowing. It is also possible to carry out the heat treatment in a vacuum (eg 0.1 to 1 mm Hg) with or without a gas flow at this reduced pressure

ORIGINAL INSPECTED

perform. The duration of the heat treatment can last from a few minutes to a few days and is generally about 1 to 6 hours. During the heat treatment of the fibers, their melting temperature gradually increases. The temperature of the atmosphere can be gradually or continuously increased or kept at a constant value during the heat treatment. For example , the fibers can be held at 250 ° C. for 1 hour, at 260 ° C. for 1 hour, and at 270 ° C. for 1 hour. It is also possible to hold the fibers for about 48 hours at a temperature between 15 ° and 20 ° C. below their melting temperature. The optimal heat treatment conditions vary with the particular composition and the inherent viscosity of the fully aromatic polyester and can be determined through routine tests.

The fibers produced from the fully aromatic polyesters according to the invention are completely oriented in the freshly spun state and have extremely good physical properties which make them suitable for use under high stresses, especially after heat treatment. The fibers as they are spun, a tear strength of the single filament of at least about 5 g / d (for example, about 5 to 11 g / den), an average tensile modulus of the filament of at least about 300 g / denier (eg, about 4OO to 7OO g / den), and they retain their physical properties and dimensional stability to an exceptional degree at elevated temperature (e.g. at temperatures of around 150 ° to 200 ° C). After the heat treatment (e.g. tempering) the fibers generally have an average tensile strength of the single thread of at least 15 g / den (e.g. 15 to 30 g / den) and an average tensile modulus of the single thread of at least 300 g / den, measured under ambient conditions (e.g. 22 ° C and 65 % relative humidity). These properties enable the

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Turning of the fibers with particular advantage as tire cord and for other technical purposes, e.g. in conveyor belts, hoses, cable sheaths, resin reinforcement etc. Films made from the fully aromatic polyesters according to the invention can be used as tensioning tape, cable sheathing, magnetic tape, dielectric sheets for electric motors, etc. can be used. The fibers and foils are naturally fire-resistant .

The invention is further illustrated by the following examples.

example 1

In a three-necked round bottom flask fitted with a stirrer, nitrogen inlet tube and a distillation head wrapped with heating tape, which was connected to a condenser the following reactants were given.

a) 151.3 g of p-acetoxybenzoic acid (0.84 mol)

b) 30.26 g of 2,6-naphthalenedicarboxylic acid (0.14 mol)

c) 54.38 g of hydroquinone diacetate (0.28 mol) d) 23.26 g of isophthalic acid (0.14 mol)

e) 0.4 g of dibutyltin oxide as a catalyst

f) 190 g of terphenyl mixture as a heat exchange medium

(Manufacturer Monsanto Co., trade name "Therminol 66")

The p-acetoxybenzoic acid, the isophthalic acid and the Hydroquinone diacetate was largely soluble in the heat exchange medium, while the 2,6-naphthalenedicarboxylic acid remained largely suspended therein as a finely divided solid.

The contents of the flask were kept under slowly flowing nitrogen throughout the polymerization reaction

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touched. The distillation head was used throughout Polymerization held at a temperature of about 100 ° to 110 ° C.

^{The reaction slurry was first heated to 200 °} C. over a period of about 20 minutes. The temperature was then gradually increased as follows: 230 ° C for 4 hours, 250 ° C for 3 hours, 280 ° C for 14 hours, 290 ° C for 2 hours, 31O ° C for 2 hours and 335 ° C for 4 hours . After approximately the first hour at 335 C, the product melted completely and settled as a liquid layer on the bottom of the flask. About 80 ml of acetic acid distillate was collected during the condensation reaction. The polymer melt was then left to cool to ambient temperature (about 25 C). After cooling, the polymer mass was finely ground in a Wiley mill, extracted with acetone and placed in an oven kept at 130 ° C. with forced ventilation 50 bis. Dried for 60 minutes.

The product obtained consisted of 168 g (about 96% of theory) of the completely aromatic polyester.

When the product is subjected to differential scanning calorimetry it showed a large, sharp endotherm at about 275 C (peak), which occurred on subsequent scans repeated on remelting at about 275 ° C. The polymer exhibited a thermotropic melt phase.

When the melt in the differential scanning calorimeter with was cooled at a rate of -20 ° C / minute, a sharp polymer crystallization exotherm appeared around 200 C (peak), a sign of rapid crystallization.

The polymer was processed by melt spinning to form a continuous filament with a single titer of about 9 denier.

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In detail, the polymer melt was at a temperature of about 290 ° C. through a single-hole nozzle with a diameter 0.508 mm and a length of 2.54 mm. The extruded thread was in ambient air (22 ° C, relative Humidity 65%). The freshly spun thread was spun at a speed of 150 m / minute wound up.

The wholly aromatic polyester thread thus prepared showed the following average ones Properties (of the single thread):

Tensile strength 6.41 g / den

Tensile modulus 4 33 g / den

Elongation 1.94%

After a heat treatment in flowing nitrogen at 270 ° C for 48 hours, with the ends of the thread attached Points corresponding to the length of the freshly spun fiber were recorded, the thread showed the following average properties (of the monofilament):

Tear strength 19.4 g / den

Tensile modulus 401 g / den

Elongation 5.1%

The thread also showed only slight shrinkage at elevated temperatures and retained the tensile strength and tensile modulus values well at temperatures up to about 150 to 20O ⁰ C.

Example 2

The experiment described in Example 1 is repeated with the difference that the following reactants in given to the flask:

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a) 151.30 g of p-acetoxybenzoic acid (0.84 McI)

b) 6O.52 g of 2,6-naphthalenedicarboxylic acid (0.28 mol)

c) 40.78 g hydroquinone diacetate (0.21 mol)

d) 13.59 g of m-phenylene diacetate (0.07 mol)

A wholly aromatic polyester having substantially the same properties is obtained.

Example 3

The following reactants were placed in a three-necked round-bottomed flask equipped with a stirrer, nitrogen inlet tube and a distillation attachment wrapped with heating tape and connected to a condenser *:

a) 151.30 g of p-acetoxybenzoic acid (0.84 mol)

b) 30.26 g of 2,6-naphthalenedicarboxylic acid (0.14 mol)

c) 54.38 g of hydroquinone diacetate (0.28 mol) d) 23.26 g of isophthalic acid (0.14 mol)

This mixture was brought to a temperature of 250.degree. At 250 ° C were the 2,6-naphthalenedicarboxylic acid and the Isophthalic acid as a finely divided solid in one of p-acetoxybenzoic acid and hydroquinone diacetate

Solution suspended. The contents of the flask were at 250 ° C stirred under slowly flowing dry nitrogen for about 2 hours while acetic acid was distilled off from the polymerization vessel. The polymerization suspension was then heated to a temperature of 280 ° C. and at this temperature for 3 hours under flowing nitrogen stirred while additional acetic acid was formed. About 80 ml of acetic acid was collected during these steps. The polymerization temperature was then increased to 320.degree. The viscous polymer melt was

Maintained under flowing nitrogen at 320 ° C. for 15 minutes and then subjected to reduced pressure in several stages. The nitrogen was shut off and the pressure increased to about

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Decreased to 300 mm Hg for about 20 minutes, to 210 mm Hg for 15 minutes, to 70 mm Hg for 15 minutes, and finally to about 0.2 mm Hg for 10 minutes. During these periods of time, the melt viscosity of the polymer increased further. The melt was stirred more slowly while the remaining acetic acid was removed from the reaction vessel. The polymer melt was then allowed to cool to ambient temperature (about 25 ° C). After cooling, the polymer stopper was finely ground in a Wiley mill and dried in an oven with air circulation for 50 to 60 minutes at 100.degree.

The product obtained consisted of 169 g (about 96% of theory) of the fully aromatic polyester. The polymer had an inherent viscosity (I.V.) of 3.02 as determined in a solution containing 0.1% by weight polyester in Contains pentafluorophenol at 60 C.

IV = ^{ln (} ^ rel)

Here, c is the concentration of the solution (0.1% by weight) and ^ rel is the relative viscosity.

When the product was subjected to differential scanning calorimetry, it showed a large sharp endotherm at about 280 ° C (peak) which was repeated on subsequent scans on remelting at about 280 ° C. The melt of the polymer was thermotropic.

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When the melt in the differential scanning calorimeter at a rate / minute was cooled from -20 ° C, a sharp polymer crystallization endotherm was observed at about 20O ⁰ C (peak), a sign of rapid crystallization.

The polymer was processed into a continuous filament of about 4.36 den / filament by melt spinning. In detail was the polymer melt, which had a temperature of 299 ° C, through a single-hole spinning nozzle with a Pressed with a diameter of 0.508 mm and a length of 2.54 mm. The extruded thread was in ambient air (about 22 ° C and 65% relative humidity). The freshly spun thread was spun at a speed wound at 690 m / minute.

The obtained freshly spun wholly aromatic polyester filament had the following average ones Properties (of the single thread):

Tensile strength 10.6 g / den

Tensile modulus 596 g / den

Elongation 2.36%

After heat treatment in flowing air at 27O ° C for 2 hours, with the ends of the fiber at fixed points corresponding to the length of the freshly spun The thread showed the following average properties (of the single thread):

Tear strength 23.6 g / den

Tensile modulus 4 38 g / den

Elongation 5.21%

The yarn also showed low shrinkage at elevated temperatures and preserved well the Reißfestigkeitsund tensile modulus at elevated temperatures up to about 150-200 ⁰ C.

709847/1116

Example 4

The experiment described in Example 3 was essentially repeated with the difference that the following reactants were added to the flask:

a) 54.04 g of p-acetoxybenzoic acid (0.30 mol)

b) 3.89 g of 2,6-naphthalenedicarboxylic acid (0.018 mol)

c) 29.13 g hydroquinone diacetate (0.15 mol)

d) 21.93 g isophthalic acid (0.132 mol)

The freshly spun thread produced was wound up at a speed of 150 m / minute.

When the product was subjected to differential scanning calorimetry, it showed an endotherm at about 300 ° C (peak). This is repeated in the subsequent scans when remelting at about 300 ° C. The melt of the polymer is thermotropic.

After melt spinning, the freshly spun thread made from the fully aromatic polyester has a single titer of 8.96 denotes the following average properties (of the single thread):

Tensile strength 7.55 g / den

Tensile modulus 380 g / den

Elongation 2.72%

After the heat treatment in flowing nitrogen for 3 hours at 2 3O ° C and for 16 hours at 25O ° C, where the filament ends were clamped at fixed points corresponding to the length of the spun yarn, the yarn had the following average properties (of the single filament) :

Tear strength 15.7 g / den

., Q tensile modulus 383 g / den

Elongation 4.2%

The thread also showed low shrinkage with increased * 709847/1 1 16

Temperatures and well preserved the tensile strength and tensile modulus values at elevated temperatures up to about 150-2OO ° C «

For comparison purposes , the experiment described in Example 4 was repeated, but the fully aromatic polyester formed from 50 mol% of p-oxybenzoyl units,

2 mol% 2,6-dicarboxynaphthalene units, 25 mol% p-dioxyphenylene units and 23 mol% isophthalene units instead of 50 mol% p-oxybenzoyl units, 3 mol% 2,6-dicarboxynaphthalene units, 25 mol% p- Dioxyphenylene units and 22 mol% isophthaloyle units existed and the thread was drawn off at a speed of 974 m / minute . The fully aromatic polyester obtained in this way had a significantly higher melting point of about 340.degree. The freshly spun thread had a single denier of 2.95 denier and the following average properties (of the single thread):

Tensile strength 3.69 g / den

Tensile modulus 316 g / den

Elongation 1.48%

After heat treatment in flowing nitrogen for

For 3 hours at 23O ° C and for 16 hours at 25O ° C , the thread had the following average properties (for the single thread):

Tensile strength 10.4 g / den

Tensile modulus 301 g / den

Elongation 3.4%

Example 5

The experiment described in Example 3 was essentially repeated with the difference that the following reactants were added to the flask :

708847/1118

a) 54.04 g of p-acetoxybenzoic acid (0.30 mol)

b) 5.19 g of 2,6-naphthalenedicarboxylic acid (0.024 mol)

c) 29.13 g hydroquinone diacetate (0.15 mol

d) 20.93 g of isophthalic acid (0.126 mol)

The freshly spun fiber obtained was drawn off at a speed of 416 m / minute.

When the product is subjected to differential scanning calorimetry it showed a sharp endotherm at about 278 ° C (peak), which occurred upon subsequent scanning repeated remelting at about 278 ° C. The melt of the polymer was thermotropic.

After melt spinning, the obtained had freshly spun Fully aromatic polyester thread has a single denier of 6.12 denier and the following average Properties (as a single thread):

Tensile strength 8.42 g / den

Tensile modulus 430 g / den

Elongation 2.94%

After the heat treatment in flowing nitrogen for 3 hours at 230 ° C and for 16 hours at 250 ° C _f with the ends of the thread clamped at fixed points corresponding to the length of the freshly spun thread, the thread showed the following average properties (as a single thread) :

Tensile strength 17.3 g / den

Tensile modulus 385 g / den

Elongation 4.6%

The thread also showed little shrinkage at elevated temperatures and retained its tear resistance well. and tensile modulus values at temperatures up to about 150-2OO ° C.

Example 6

The experiment described in Example 3 was essentially carried out

chen repeated except that the following reactants were added to the flask:

a) 54.04 g of p-acetoxybenzoic acid (0.30 mol)

b) 6.49 g of 2,6-naphthalenedicarboxylic acid (0.03 mol) c) 29.13 g of hydroquinone diacetate (0.15 mol)

d) 19.94 g isophthalic acid (0.12 mol)

The freshly spun thread formed was drawn off at a speed of 150 m / minute.

When the product is subjected to differential scanning calorimetry it showed a sharp endotherm at about 263 ° C (peak), which occurred upon subsequent scanning repeated remelting at about 26 3 ° C. The melt of the polymer was thermotropic.

After melt spinning, the freshly spun thread obtained was made of the wholly aromatic polyester a single titer of 16.9 denier and the following average properties (as a single thread):

Tensile strength 6.90 g / den

Tensile modulus 369 g / den

Elongation 2.63%

After heat treatment in flowing nitrogen for 3 hours at 230 ° C and for 16 hours at 250 ° C, whereby the ends of the thread were clamped at fixed points corresponding to the length of the freshly spun thread, the thread showed the following average properties (as a single thread):

Tear strength 21 g / den

Tensile modulus 341 g / den

Elongation 6.2%

The thread also showed little shrinkage at elevated temperatures and retained tear strength well Tensile modulus values at temperatures up to approx. 150 - 200 ° C.

709847/1116

Example 7

The experiment described in Example 3 was essentially repeated, except that the following reactants were added to the flask:

a) 54.04 g of p-acetoxybenzoic acid (0.30 mol)

b) 16.21 g of 2,6-naphthalenedicarboxylic acid (0.075 mol)

c) 29.13 g hydroquinone diacetate (0.15 mol)

d) 12.46 g isophthalic acid (0.075 mol)

Furthermore, the freshly spun thread was drawn off at a speed of 500 m / minute.

When the product is subjected to differential scanning calorimetry it showed a sharp endotherm at about 262 ° C (peak) which was reflected in subsequent scans repeated on remelting. The melt of the polymer was thermotropic.

After melt spinning, the freshly spun thread obtained was made of the wholly aromatic polyester a single titer of 3.97 den and the following average Properties (as a single thread):

Tensile strength 8.00 g / den

Tensile modulus 385 g / den

Elongation 3.01%

After heat treatment in flowing nitrogen for 3 hours at 230 ° C and for 16 hours at 250 ° C, whereby the ends of the thread were clamped at fixed points corresponding to the length of the freshly spun thread, the thread exhibited the following average properties (as a single thread):

Tensile strength 20.0 g / den, tensile modulus 311 g / den

Elongation 5.5%

The thread also showed little shrinkage at elevated temperatures and retained tear strength well Tensile modulus values at temperatures up to approx. 150 - 200 ° C.

709847/1116

Claims (23)

Claims Improved melt-processable wholly aromatic polyester capable of forming a thermotropic melt phase at a temperature below about 300 ⁰ C, consisting essentially of the following recurring units I, II, III and IV: III: a symmetrical dioxyaryl unit of the formula I-0 Ar 0-1-, where Ar is a divalent radical that has one or more fused or separate aromatic rings (i.e. at least contains an aromatic ring), and IV: repeating units of the formulas C). and mixtures of (a) and (b), 709847 / 111B ORIGINAL INSPECTED 2721707 wherein the polyesters contain about 20 to 70 mol% of unit I, about 3 to 30 mol% of unit II, about 7.5 to 40 mol% of unit III and about 4 to 30 mol% of unit IV and each of these units is free of ring substitution . 2. Polyester according to claim 1, characterized in that they are able to form a thermotropic melt phase at a temperature below about 280 ° C. 3. Polyester according to claim 1 and 2, characterized in that the symmetrical dioxyaryl unit is a unit of the formula 70 9 847/1116 2721797 or a mixture of these units. 4. Polyester according to claim 1, characterized in that the unit IV is a unit of the formula (a) - C- --ι 11 " O C- is. 5. Fibers produced by melt spinning from the fully aromatic polyesters according to claims 1 to 4. 6. fibers, characterized in that they are melt-spun from the fully aromatic polyesters according to claim 1 and then subjected to a heat treatment. 7. Improved, melt processable, fully aromatic polyesters that are made at a temperature below about
300 ° C are able to form a thermotropic melt phase and consist of the following recurring units I, II, III and IV: ■■ -O ■ - ( 709847/1116 wherein the polyester is about 40 to 60 mol% of the unit I, about 3 to 15 mol% of unit II, about 20 to 30 mol% of unit III and about 10 to 27 mol% of unit IV contain. 8. Fibers produced by melt spinning the wholly aromatic polyesters according to claim 7. 9. fibers, characterized in that they are melt-spun from the fully aromatic polyesters according to claim 7 and then subjected to a heat treatment. 10. Polyester according to claim 1, characterized in that it is about 40 to 70 mole percent of unit I, about 7.5 to 30 mole percent of unit II, about 7.5 to 30 mole percent of unit III and about 4 to 20 mol% of the unit IV and each unit of the polyester free of ring substitution is. 11. Polyester according to claim 10, characterized in that it has a temperature below about 280 C. able to form thermotropic melt phase. 12. Polyester according to claim 10, characterized in that the symmetrical dioxyaryl unit is a unit the formula 47/1116 ,> - ■ O-f— ο - CH CU, - O ■ - <■ O - (■ ο- -ο- > —Ο— or a mixture of these units. 13. Polyester according to claim 10, characterized in that the unit IV is a unit of the formula ο ~ i is. 709847/1116 14. Fibers produced by melt spinning from the wholly aromatic polyesters according to claim 10. 15. Fibers, characterized in that they are melt-spun from the fully aromatic polyesters according to claim 10 and subsequent heat treatment have been produced. 16. Improved, melt-processable, fully aromatic polyesters that are processed at a temperature below
of about 300 ⁰ C are able to form a thermotropic melt phase and consist of the following recurring units I, II, III and IV: Q
C-- II III IV: units of the formula (a) and mixtures of (a) and (b), the polyesters about 40 to 70 mol% of unit I, about 7.5 to 30 mol% of unit II, about 7.5 to
Mole percent of the unit III and about 4 to 20 mole percent of the 709847/1116 Unit IV included. 17. Polyester according to claim 16, characterized in that the unit IV is a unit of the formula 0 -C- is. 18. Polyester according to claim 17, consisting of about 60 mol% of unit I, about 10 mol% of unit II, about 20 mol% of unit III and about 10 mol% of unit IV. 19. Polyester according to claim 16, characterized in that the unit IV is a unit of the formula "O O is. 20. Polyester according to claim 19, consisting of about 60 mol% of unit I, about 20 mol% of unit II, about 15 mole percent of unit III and about 5 mole percent of unit IV. 21. Fibers, characterized in that they are melt spun produced from the fully aromatic polyesters according to claim 16 and subsequent heat treatment and an average tensile strength of the monofilament of at least 15 g / den and an average Tensile modulus of the single thread of at least 709847/1116 300 g / den, measured at ambient conditions. 22. Fibers according to claim 21, characterized in that they have been subjected to the heat treatment in an inert atmosphere. 23. Fibers according to claim 21, characterized in that they have been subjected to the heat treatment in an oxygen-containing atmosphere. 709847/1116