CA1174788A - Poly(ester-amide) capable of forming an anisotropic melt phase derived from 6-hydroxy-2-naphthoic acid, dicarboxylic acid and aromatic monomer capable of forming an amide linkage - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
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 propor-tions 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°C., preferably below approximately 350°C. The poly(ester-amide) of the present invention is pre-ferably formed by a melt polymerization technique.

Description

1~7~L7~3 BACKGROUND OF THE I~VE~TION
The use of objects molded from synthetic polymers has expanded rapidly in the last several decades. In particular, polyesters and polyamides have widely gained acceptance for general molding applications and in the formation of fibers and films. An additional class of polymers known as poly(ester-amides) has been disclosed. ~uch disclosures include U.S.
Patent Nos. 2,547,113; 2,9~6,769; 3,272,774; 3,272,776, 3,440,218; 3,475,385; 3,538,058; 3,546,178, 3,575,928;
3,676,291; 3,865,792; 3,926,923; and 4,116,943. Polyimide esters are disclosed in German Offenlegungsschrift No. 2,950,939 and in U.S. Patent No. 4,176,223.
Although many polyesters, polyamides, and poly(ester-amides)llave mechanical propertias suitable for general applica-tions, most polyesters, polyamides, and poly(ester-amides) are not suitable for high strength service because the mechanical properties are not suficiently high. One group of polymers that are suitable for high strength service without the use o~ a reinforcing agent is a new class of polymers exhibiting a 20 general overall balance of mechanical properties substantially enhanced over previous polymers. These polymers have been described by various terms, including "liquid crystalline", "liquid crystal", and "anisotropic"~ Briefly, the polymers of this new class are thought~O involve a parallel ordering of the molecular chains. The state wherein the molecules are so ordered is often referred to either as the liquid crystal state or the nematic phase of the liquid crystal state~ These poly-mers are prepared from monomers which are generally long, flat, and fairly rigid along the long

-2-~747~B

axis of the molecule and commonly have chain ex~ending linkages that are either coaxial or parallel.
Disclosures of polyesters which exhibit melt anisotropy include (a) Polyester X7G-A Self Reinforced Thermoplastic, by W.J. Jackson Jr., ~I.F. Kuhfuss, and T.F. Gray, Jr., 30th Anniversary Technical Conference, 1975 Reinforced Plastics/Composites Institute, The Society of t~e Plas*ics Industry, Inc., Section 17-D, Pages 1 to 4, (b) Belgian Patent Numbers 828,935 and 828,936, (c) Dutch Patent Number 7505551, (d) West German Numbers 2520819, 2520820, 2722120, 2834535, 2834536, and 2834537, (e) Japanese Numbers 43-223; 2132-116; 3017-692; and 3021-293, (f) United States Patent Numbers 3,991,013; 3,991,014; 4,057,597; 4,066,620; 4,067,852;
4,075,262; 4,083,829; ~,118,372; 4,130,545; 4,130,702; 4,156,070; 4,159,365;
4,161,470; 4,169,933; 4,181,792; and 4,184,996; and (g) United Kingdom Application Number 2,002,404 published February 21, 1979. See also commonly assigned United States Patent Number 4,238,599 issued December 9, 1980;
United States Patent Number 4,238,598 issued Decmeber 9, 1980; United States Pa~nt Number 4,219,461 issued August 26, 1980; and United States Patent Number 4,256,624 issued March 17, 1981.
Disclosures of liquid crystalline polyamide dopes include United States Patent Numbers 3,637,143; 3,748,299; 3,767,756; 3,801,528; 3,804,791;

3,817,941; 3,819,587; 3,827,998; 3,836,498; 4,016,236; 4,018,735; 4,148,774;
and Re. 30,352.
United States Patent Number 4,182,842 discloses poly(ester-amides) prepared from an aromatic dicarboxylic acid, ethylene glycol, and a p-acyl-aminobenzoic acid. This patent neither discloses nor suggests the poly(es~er-amide) of the present invention. A similar disclosure is Japan 54 125271.
European Patent Application Number 79301276.6 (Publication No.
0 007 715) discloses melt processable fiber-forming poly(ester--~r---~

3L~7~7~

amides) comprising residues of one or more aminophenols selected from p-aminophenol and p-N-methylaminophenol and residues of one or more dicarboxylic acids. The poly(ester-amide) contains a balance of linear difunctional residues and dissymetric difunc-tional residues derived from either the aminophenols or the acids. The linear difunctional residues and dissymetric difunc-tional residues are chosen so as to give a product which melts below its decomposition temperature and exhibits opt~cal aniso-tropy in the melt. This patent neither discloses nor suggests the poly(ester-amide) of the present invention which contains a 6~oxy-2-naphthoyl moiety.
U.S. Patent No. 3j859,251 discloses a poly(ester-amide) which comprises 50 to 100 mole percent of the moiety derived from an acyclic aliphatic di~arboxylic acid. Such a moiety is excluded from the poly~ester-amide) of the present invention. Moreover, while the patent discloses the inclusion of a p-oxybenzoyl moiety, there is no disclosure nor suggestion of the usefulness of a poly(ester-amide) containing a 6-oxy-2-naphthoyl moiety, such as that of the present invention.
U.S. Patent No. 3,809,679 discloses poly(ester-amides) consisting of 10 to 90 mole percent of recurring structural units derived from a dicarboxylic acid dihalide and a dihydroxy compound of a specified formula and 10 to 90 mole percent of r~curring structural units derived from a dicarboxylic acid dihalide and a diamino compound of a specified formula. The poly(ester-amides) specifically exclude moieties derived from aromatic hydroxyacids, such as the 6-oxy-2-naphthoyl moiety included in the poly(ester-amide) of the present invention.
Furthermore, most, if not all, of the poly(ester-amides) dis~
closed are not

-4-7~
readily melt processable, and there is no disclosure of the existence of an anisotropic melt phase.
According to the present invention, a melt processable poly(ester-amide) capable of forming an anisotropic melt phase at a temperature below approximately 400C. is provided. The poly(ester-amide) consists essential-ly of the recurring moieties I, II, III, and, optionally, IV l~lherein l is ~ O O

II is - - C - A - C - -, where A is a divalent radical comprising at least one aromatic ring or a divalent trans-1,4-cyclohexylene radical;

III is ~Y - Ar - Z ~ , where Ar is a divalent radical comprising at least one aromatic ring, Y is O, N~l, or NR, and Z
is NH or NR, where R is an alkyl group of 1 to 6 carbon atoms or an aryl group; and IV is ~ O - Ar' - O 3 where Ar' is a divalent radical comprising at leas~ one aromatic ring;

wherein at least some of the hydrogen atoms present upon the rings option-ally may be replaced by substitution selected from the group consisting of an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, halogen, phenyl, and mixtures thereof, and wherein said poly~ester-amide) comprises approximately 10 to 90 mole percent of moiety I, approx-imately 5 to 45 mole percent of moiety II, approximately 5 to 45 mole per-cent of moiety III, and approximately 0 to 40 mole percent of moiety IV.

One aspect of the invention provides a moulding compound which contains the melt processable poly(ester-amide) mentioned above and approximately 1 to 60 percent by weight of a solid filler and/or reinforcing material.
Another aspect of the invention provides a molded article com-prising the melt processable poly(ester-amide) mentioned above.
Still another aspect of the invention provides a fiber which has been melt spun from the mel~ processable poly(ester-amide) mentioned above.
Still a further aspect of the invention provides a film which has been melt extruded from the poly(ester-amide) mentioned above.
Still a further aspect of the invention provides a process for the preparation of the melt processable poly(ester-amide) which comprises:
reacting (i) approximately 10 to 90 mole percent of 6-hydroxy-2-naphthoic acid of the formula ~(:00~1 HO ~

or a reactive derivative thereof, (ii) approximately 5 to 45 mole percent of a dicarboxylic acid of the formula HOOC-A-COOH

wherein A is a divalent radical comprising at least one aromatic ring or a divalent trans-1,4-cyclohexylene radical, or a reactive derivative thereof, (iii) approximately 5 to 45 mole percent of a compound of the formula H-Y-Ar-~-H

7~8 wherein Ar is a divalent radical comprising at least one aromatic ring, Y is O, ~1 or NR, and Z is NH or NR, where R is analkyl group of 1 to 6 carbon atoms or an aryl group, or a reactive derivative thereof, and (iv) approximately 0 to 40 mole percent o an aromatic hydroxy compound of the ormula HO-Ar'-OH

wherein Ar' is a divalent radical comprising at least one aromatic ring, or a reactive derivative thereof, until substantially the reaction is completed, wherein at least some of the hydrogen atoms present on the rings optionally may be replaced by substituents selected from the group consisting of an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, halogen, phenyl, and mixtures thereof.

- 6a -~L7~7~3 DESCRIPTIO~ OF THE PREFERRED EMBODIMENTS
The poly(ester-amide) of the present invention consists essentially of at least three recurring moieties which when combined in the poly(ester-amide) have been found to form an atypical, optically anisotropic melt phase. The polymer forms an anisotropic melt phase at a temperature below approxi-mately ~00C. (e.g., below approximately 350C.). The polymer melting temperatures may be confirmed by the use of a differen-tial scanning calorimeter (i.e., DSC) employing repeat scans at a 20C. per minute heat-up rate and observing the peak of the DSC melt transition. The poly(ester-amide) commonly exhibits a melting temperature of atleast approximately 200C. and prefer-ably of at least approximately 250C. as determined by differen-tial scanning calorimetry. The poly(ester-amide) of the present invention may exhibit more than one DSC transition temperature.
Because o* its ability to exhibit anisotropic proper-ties (i.e., liquid crystalline properties) in the melt, the poly(ester-amide) readily can form a product having a highly oriented molecular structure upon melt processing. Preferred poly(ester-amide) compositions are capable of undergoing melt processing at a temperature within the range of approximately 250C. to 350C., as discussed more fully hereinafter.
The poly(ester-amide) comprises three essential moieties. Moiety I can be termed a 6-oxy~2-naphthoyl moiety and possesses the structural formula:

_7_ - ro~ .

While not specifically illustrated in the structural formula, at least some of the hydrogen atoms present upon the aromatic rings of moiety I may be substituted. Representative ring substituted compounds from which moiety I
can be derived include: 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy -5-methyl-2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid, 6-hydroxy-7-chloro-2-naphthoic acid, 6-hydroxy-5,7-dichloro-2-naphthoic acid, etc.
The presence of ring substitution tends to modify to some degre~ the physical properties of the resulting polymer (e.g., the polymer may soften at a lower temperature, its impact strength may be improved, and the crystallinity of the solid polymer may be decreased). In a preferred embodiment wherein a poly~ester~amide) of optimum crystallinity in the solid state is desired, no ring substitution is present.
As will be apparent to those skilled ln the art, moiety I can be derived from unsubstituted 6-hydroxy-2-napthoic acid and the derivatives thereof. A convenient laboratory preparation for forming 6-hydroxy-2-naphthoic acid is described in ~erichte, Vol. 589 2835-45 ~1925) by K. Fries and K. Schimmelschmidt. Also, United States Patent Number 1J593~816 is concerned with a process for synthesizing 6-hydroxy-2-napthoic acid by reacting carbon dioxide with the potassium salt of beta-naphthol.
Moiety I comprises approximately 10 to 90 mole percent of poly-~ester-amide). In a preferred embodiment, moiety I is present in a concen-tration of approximately 40 to 80 mole percent, and most preferably in a con-centration of approximately 40 to 60 mole percent.

~ i~r~'~

~47~1~

.. .

The second essential moiety (i.e., moiety II) is a dicarboxy moiety of the formula ~ C - ~ cl,where A is a diva-lent radical comprising at least one aromatic ring or a divalent trans-1,4-cyclohexylene radical. Moiety II is preferably a dicarboxyaryl moiety, and is more preferably a symmetrical dicar-bo~yaryl moiety. By ~'symmetrical~' it is meant that the divalent bonds which join the moiety to other moieties in the main polymer chain are symmetrically disposed on one or more rings (e.g., are para to each other or diagonally disposed when present on a naohthalene ring).
The preferred moiety which may serve as a symmetrical dicarboxyaryl moiety in the polyester of the present invention is a terephthaloyl moiety. An example of a non-symmetrical dicar-boxyaryl moiety is an isophthaloyl moiety. Although moiety II
may be substituted in the same manner as moiety I, highly satis-factory polymers can be formed wherein the dicarboxyaryl moiety is free of ring substitution.
In the case where A is a divalent 1,4-cyclohexylene radical, it has been found that only moiety II units in the trans conflguration give rise to a poly(ester-amide) which exhibits anisotropy in the,melt phase. This is be~ieved to be due to the disruption and destruction of the rod-like nature of the polymer molecules by the presence of moiety II units in the cis confi-guration. However, a relatively small amount of moiety II in the cis configuration, as compared with the total amount of polymer, can be tolerated without seriously affecting the anisotropic nature of the polymer in the melt. It is nevertheless preferable to maximize the amount of moiety II in the trans configuration which is present in the polymer. Thus, it is preferred that at _g _ 7~

least 90 percent ~e.g., 95 percent or more) oE the l,A-cyclohexy-lene radicals be present in the trans configuration.
Trans- and cls-1,4-cyclohexaneclicar~oxylic acid can be distinguished from one another by such techniques as NMR and IR
spectroscopy, as well as by their melting points. A melting point calibration curve is one means by which the reiative amounts of trans- and cis-1,4-cyclohexanedicarboxylic acid in a mix~ure of the isomers can be determined.
~ oiety II comprises approximately 5 to 45 mole percent of the poly(ester-amide), and preferably approximately 5 to 30 mole percent (e.g., approximately 20 to 30 mole percent).
~ loiety III represents an aromatic monomer which is capable of forming an am;de linkage in the polymer. Moiety III
possesses the structural formula ~Y-Ar-~, where Ar is a divalent radical comprising at least one aromatic ring, Y is O, ~, or NR, and z is NH or ~R, wnere R is a alkyl group of 1 to 6 carbon atoms or an aryl group. R is preferably a straight-chain alkyl group of 1 to 6 carbon atoms and is more preferably a methyl group. Examples of monomers from which moiety III is derived nclude p-aminophenol, p-N-methylaminophenol, p-phenylenediamine, ~-methyl-p-phenylenediamine, N,N'-dimethyl-p-phenylenediamine, m-aminophenol, 3-methyl-4-aminophenol, 2-chloro-4-aminophenol, 4-amino-l-naphthol, 4-amino-4'-hydroxy-diphenyl, 4-amino-4'-hydroxydiphenyl ether, 4-amino-4'-hydroxydiphenyl methane, 4-amino-4'-hydroxydiphenyl ethane, 4-amino-4'-hydroxydiphenyl sul-fone, 4~amino-4'-hydroxydiphenyl sulfide, 4,4~-diaminophenyl sul~ide (thiodianiline), 4,4'-diaminodiphenyl sulfone, 2,5-diaminotoluene, 4,4~-ethylenedianiline, and 4,4'-diaminodiphe-noxyethane.

7~

~ gain, although moiety III can be substituted, it is preferably free of ring substitution.
~ loiety III comprises approximately 5 to 45 mole percent of the poly(ester-amide). In a preferred embodiment, moiety III
is present in ~ concentration of approximately 5 to 3n mole per-cent.
In addition to the three essential moieties described above, the pol~(ester-amide) may further comprise an additional moiety (moiety IV). Moiety IV can be termed a dioxyaryl moiety and has the formula ~O-Ar'-O~ where Ar' is a divalent radical comprising at least one aromatic ring. Moiety IV preferably is symmetrical in the sense that the divalent bonds which join the moiety to other moieties in the main polymer chain are symmetri-cally disposed on one or more aromatic rings (e.g., are para to each other or diagonally disposed wherl present on a naphthalene ring). Preferred moieties which may serve as a symmetrical dioxyaryl moiety in the polytester-amide) of the present inven-tion include:

r O ~ ~_0~ ~

113~

~o (~ o~}

~-~

8~

.

rO ~ _l - o~

r O ~_s--~--o--~ /,/ o-C1l2-~l2-o~

,~ , C}12-Cl12~ 3 }

and mixtures of the foregoing. Highly satisfactory polymers can be formed wherein the dioxyaryl moiety is free of ring substitu-tion.
A particularly preferred dioxyaryl moiety is:
~~

hich readily may be derived from hydroquinone. Represen~ative examples of ring substituted compounds from ~hich moiety IV can be derived include methylhydroquinone, chlorohydroquinone, bro-~74~88 mohydroquinone, phenylhydroquinone, etc. An example of a non-symmetrical dioxyaryl moiety is that derived from resorcinol.
Moiety IV comprises approximately 0 to 40 mole percent of the poly(ester-amide), preferably approximately 0 to 25 mole percent, and most preferably approximately 0 to 15 mole percent.
The substituents, if present, on each of the moieties described above are selected from the ~roup consisting of an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 L0 carbon atoms, halogen, phenyl, and mixturesof the foregoing.
Other ester-forming moieties (e.g., dicarboxy, dioxy, or hydroxycarboxy units) other than those previously discussed additionally may be included in the poly(ester-amide) of the present invention in a minor concentration so long as such moieties do not adversely influence the desired anisotropic melt phase exhibited by the poly(ester-amide) heretofore defined and do not raise the melting point of the resulting polymer.
As will be apparent to those skilled in the art, the total molar quantity of amide-forming units and dioxy units, if present, and the total molar quantity of dicarboxy units present wtihin the poly(ester-amide) will be sub~tantially equal. That is, the molar quantity of moiety II and the total molar quantity of moieties III and IV commonly are substantially equal. The various moieties upon polymer formation will tend to be present in a random configuration.
It is further apparent to those of ordinary skill in the art that the total molar concentration, in mole percent, of moieties II, III, and IV in the polymer is determined by sub-tracting the molar concentration of moiety I from 100 mole percent.

47~

The poly(ester-amide) of the present invention commonly exhibits -O-C-CH3, -C-OH, -NH-C-CH3, or -~R-C-CH3 end groups depending upon the synthesis route selected. As will be apparent to those skilled in the art, the end groups optionally may be cap~ed, e.g., acidic end groups may be capped with a variety of alcohols, and hydroxyl end groups may be capped with a variety of organic acids. For instance, end capping units such as phenyl ester (-C-O ~ ) and methylester (-C-O-CH3) optionally may be included at the end of the polymer chains. The polymer also may be oxidatively cross-lin~ed to at least some degree, if desired, by heating in an oxygen-containing atmosphere (e.g., in air) while in bulk form or as a previously shaped article at a tem-perature below its melting temperature for a limited period of time (e.g., for a few minutes).
The poly(ester-amide) of the present invention tends to be substantially insoluble in all common solvents, such as hexa-fluoroisopropanol and o-chlorophenol, and accordingly is not susceptible to solution processing. It can surprisingly be readlly processed by common melt processing techniques as dis-cussed herea~ter. Most compositions are soluble to some degree in pentafluorophe,nol.
The poly(ester-amide) of the present invention commonly exhibits a weight average molecular weight of about 5,000 to about 50,000, and preferably about 10,000 to 30,000, e.g., about 15,000 to 17,500. Such molecular weight may be determined by standard techniques not involving the solutioning of the polymer, e.g., by end group determination via infrared spectroscopy on compression molded films. Alternatively, light scattering tech-niques in a pentafluorophenol solution may be employed to determine the molecular weight.

,................................................................. .

~L~7~
The poly(ester-amide) of the present invention is capable of undergoing melt processing at a temperature within the range of approximately 200C. to 400C. Preferably, the polymer is melt processed at a temperature within the range of approximately 250C. to 350C. and more preferably within the range of approximately 270C. to 330C.
The melting temperature (Tm) of the poly(ester-amide) of the present invention may vary widely with the composition of the poly(ester-amide). For example, a poly(ester-amide) prepared from 6-hydroxy-2-naphthoic acid (H~A), terephthalic acid, and p-aminophenol exhibits a melting temperature of approximately 360C. at 80 mole percent HNA. The melting temperature drops to a minimum, for the particular poly(ester-amide), o~ approximately 276C. at approximately 66 mole percent HNA and then increases again to approximately 326C. at 50 mole percent HNA.
The poly(ester-amide) prior to heat treatment addi-tionally commonly exhibits an inherent viscosity (i.e., I.~.) of at least approximately 1.0 dl./g., and preferably at least 20 approximately 2.0 dl./g. (e.g., approximately 3.0 to 8.0 dl./g.) when dissolved in a concentration of 0.1 percent by weight in pentafluorophenol at 60C.
The poly(ester-amide) of the present invention commonly may be considered crystalline in the sense that fibers melt extruded therefrom exhibit X-ray diffraction patterns using ~i-filtered CuK ~ radiation and flat plate cameras character-istic of polymeric crystalline materials. In those embodiments wherein ring substitution is present as previously described or wherein certain aryl diols, such as 2,2-bis[4-hydroxyphenol]pro-pane, are present, the polyesters may be substantially less ~L7~17~38 crystalline in the solid phase and exhibit diffraction patterns typical of oriented amorphous fibers. In spite of the crystal-linity commonly observed, the poly(ester-amide) of the present invention nevertheless may be easily melt processed in all instances.
The polytester-amide) of the present invention is readily tractable and forms an anisotropic melt phase whereby an atypical degree of order is manifest in the molten polymer. The improved tractability of the present poly(ester-amide) is due, at least in part, to the presence of moiety I, i.e., the 6-oxy-2-naphthoyl moiety. It has been observed that the tractability of the polymer is a function o the molar concentration of moiety I in the polymer.
The subject poly(ester-amide) readily forms liquid crystals in the melt phase. Such anisotropic properties are manifest at a temperature which is amenable for melt processing to form shaped artic]es. Such order in the melt may be confirmed by conventional polarized light techniques whereby crossed polarizers are utilized. More specifically, the aniso-tropic melt phase may conveniently be confirmed by the use of aLeitz polarizing microscope at a magnification of 40X with the sample on a Leitz hot stage and under a nitrogen atmosphere.
The polymer melt is optically anisotropic, i.e., it transmits light when examined between crossed polarizers. Light is trans-mitted when the sample is optically anisotropic even in the static state.
The poly(ester-amide~ of the present invention may be formed by a variety of techniques whereby organic monomer com-pounds possessing functional groups which upon condensation form the requisite recurring moieties are reacted. For instance, the functional groups of the organic monomer compounds may be car-~74~

boxylic acid groups, hydroxyl groups, ester groups, acyloxy groups, acid halides, amine groups, etc. The organic monomer compounds may be reacted in the absence of a heat-exchange fluid via a melt acidolysis procedure.
They accordingly, may be heated initially to form a melt solution of the reactants with the reaction continuing as solid polymer particles are formed and suspended therein. A vacuum may be applied to facilitate removal of volatiles formed during the final stage of condensation (e.g., acetic acid or water). Such a technique is disclosed in European Patent Application Number 79301276.6 ~Publication No. 0 007 715).
In commonly assigned United States Patent No. 4~067J852 of Gordon W. Calundann, entitled "Melt Processable Thermotropic Wholly Aromatic Polyester Containing Polyoxybenzoyl Units" is described a slurry polymeriZ-ation process which, although directed to the production of wholly aromatic polyesters, may be employed to form the poly~ester-amide) of the present invention. In that process, the solid product is suspended in a heat exchange medium.
When employing either the melt acidolyses procedure or the slurry procedure of United States Patent No. 4,067,852, the organic monomer reactants from which the 6 oxy-2-naphthoyl moiety ~i.e., moiety I), the amide-forming moiety ~i.e., moiety III), and the optional dioxyaryl moiety ~i.e., moiety IV), are derived may be initially provided in a modified form whereby the usual hydroxyl groups of these monomers are esterified ~i.e., they are provided as acyl esters). For instance, lower acyl esters of 6-hydroxy-2-naphthoic acid, p-aminophenol, and hydroquinone, ~7~7~3~

wherein the hydroxy groups are esterified, may be provided as reactants. The lower acyl groups preferably have from about 2 to about 4 carbon atoms. Preferably, the acetate esters of the organic compounds which ~orm moieties I, III, and IV are pro-vided. In addition, the amine group of moiety III may be provided as a lower acyl amide. Accordingly, particularly preferred reactants for the condensation reaction are 6-acetoxy-2-naphthoic acid, p-acetoxyacetanilide, and hydroquinone diace-tate.
Representative catalysts which optionally may be employed in either the melt acidolysis procedure or in the procedure of United States Patent ~o. 4,067,852 include alkyl tin oxide (e.g., dibutyl tin oxide), diaryl tin oxide, alkyl tin acids, acyl esters of tin, titanium dioxide, alkoxy titanium silicates, titanium alkoxides, alkali and alkaline earth metal salts of carboxylic acids (e.g., sodium acetate), the gaseous acid catalysts such as Lewis acids (e.g., ~F3), hydrogen halides (e.g., HCl), etc. The quantity o catalyst utilized typically is about 0.001 to 1 percent by weight based upon the total monomer weight, and most commonly about 0.01 to 0.12 percent by weight.
The molecular weight of a previously formed polyester may be further increased via a solid state polymerization proce-dure wherein the particulate polymer is heated in a flowing inert gaseous atmosphere (e.g., in a flowing nitrogen atmo-sphere) at a temperature approximately 20C. below the melting temperature of the polymer for 10 to 12 hours.
The poly(ester-amide) of the present invention readily can be melt processed to form a variety of shaped articles, e.g., molded three-dimensional articles, fibers, films, tapes, etc. The poly(ester-amide) of the present invention is suited ~1 ~L7~7~

for molding applications and may be molded via standard injec-tion molding techniques commonly utilized when forming molded articles. It is not essential that more severe injection molding conditions (e.g., higher temperatures, compression molding, impact molding, or plasma spraying techniques) be utilized. Fibers or ilms may be melt extruded.
A molding compound may be formed from the poly(ester-amide) of the present invention which incorporates approximately 1 to 60 percent by weight of a solid filler (e.g., talc) and/or reinforciny agent (e.g., glass fibers).
The poly(ester-amide) also may be employed as a coating material which is applied as a powder or from a liquid dispersion.
When forming fibers and films, the extrusion orifice may be selected from among those commonly utilized during the melt extrusion of ~uch shaped articles. For instance, the shaped extrusion orifice may be in the form of a rectangular slit (i.e., a slit die) when forming a polymeric film. When forming a filamentary material, the spinneret selected may contain one and preferably a plurality of extrusion orifices.
For instance, astandard conical spinneret, such as those common-ly used in the melt spinning of poly(ethylene terephthalate~, containing 1 to 2000 holes (e~g., 6 to 1500 holes) having a diameter of about 1 to 60 mils (e.g. 5 to 40 mils) may be utilized. Yarns of about 20 to 200 continuous filaments are commonly formed. The melt-spinnable poly(ester-amide) is supplied to the extrusion orifice at a temperature above its melting point, e.g., a temperature of about 270C. to 330C. in preferred embodiments.

Subsequent to extrusion through the shaped orifice, the resulting filamentary material or film is passed in the direction o its length through a solidification or quench zone wherein the molten filamentary material or film i5 transformed into a solid filamer.tary material or film. The resulting fibers commonly have a denier per filament of about 2 to 40, and preferably a denier per filament of about 3 to 5.
The resulting filamentary material or film optionally may be subjected to a thermal treatment whereby its physical properties are further enhanced. The tenacity of the fiber or film generally is increased by such thermal treatment. More specifically, the fibers or films preferably may be thermally treated in an inert atmosphere (e.g., nitrogen, argon, helium) or alternatively in a flowing oxygen-containing atmosphere (e.g., air) with or without stress at a temperature below the polymer melting point until the desired property enhancement is achieved. Thermal treatment times commonly range from a few minutes to several days. Generally, as the product is thermally treated, its melting temperature progressively is raised. The temperature of the atmosphere may be staged or continuously increased during the thermal treatment or held at a constant level. For instance, the product may be heated at 250C. for one hour, at 260C. for one hour, and at 270C. for one hour.
Alternatively, the product may be heated at about 10C. to ~0~C.
below the temperature at which it melts for about 45 hours.
Optimal heat treatment conditions will vary with the specific composition of the poly(ester-amide~ and with the process history of the product.

~79~7~38 The as-spun fibers formed from the pol~(ester-amide) of the present invention are fully oriented and exhibit highly satisfactory physical properties which rendex them suitable for use in high performance applications. The as-spun fibers commonly exhibit an average single filament tenacity of at least 1 gram per denier (e.g., about 3 to 10 grams per denier) and an average single filament tensile modulus of at least about 200 grams per denier (e.g., about 300 to 800 grams per denier) and exhibit an extraordinary dimensional stability at elevated temperature (e.g., at temperatures of about 150 to 200C.).
Following thermal treatment (i.e., annealing), the fibers commonly exhibit an average single filament tenacity of at least

5 grams per denier (e.g., 15 to 40 grams per denier). Such properties enable the fi~ers to be us0d with particular advan-tage as tire cords and in other industrial applications, such as conveyor belts, hose, rope, cabling, resin reinforcement, etc.
Films formed of the polyester of the present invention may be used as strapping tape, cable wrap, magnetic tape, electric motor dielectric film, etc. The fibers and films exhibit an inherent resistance to burning.
It is anticipated that the poly(ester-amide) composi-tions of the present invention will exhibit improved adhesion, improved fatigue resistance, and increased transver e strength over known polymers, such as wholly aromatic polyesters.
The following Examples are presented as specific illustrations of the claimed invention. It should be under-stood, however, that the invention is not limited to the speci-fic details set forth in the Examples.

~21-~a~7~7~3~

This Example illustrates the preparation of a poly-(ester-amide) from 6-hydroxy-2-naphthoic acid, terephthalic acid, p-aminophenol, and hydroquinone (or derivatives thereof) in the molar ratio 60:20:10:10.
A 300 ml. 3-neck polymer flask was fitted with a sealed glass paddle stirrer, a gas inlet, and a distillation head and condenser. Into the flask were placed 69 g. (0.3 mole) of 6-acetoxy-2-naphthoic acid, 1606 g. (0.10 mole~ of tere-phthalic acid, 9.7 g. (0.050 mole) of p-acetoxyacetanilide, and 9.8 g. (0.051 mole) of hydroquinone diacetate. 0.2 g. of sodium acetate was added as a catalyst. The flask was evacuated and flushed with nitrogen 3 times. The flask was heated in an oil bath to 250C. under a slow stream of nitrogen gas. The contents melted to an opaque slurry and agitation was begun.
Acetic acid began to distill over and was collected in a gradu-ated cylinder. After 45 minutes at 250C., in 16 ml. of acetic acid had been collected. The temperature was then raised to 280C. The melt was an opaque pale tan color. Heating conti-nued at 280C. for another 45 minutes, by which time 25 ml. of acetic acid had been collec~ed (87%) of the theoretical yield).
At one stage, the melt became very foamy, but gradually, as the melt became more viscous, the foaming decreased. The tempera-ture was then raised to 320C. Foaming initially se-t in but gradually disappeared, as before, to give a smooth creamy opaque melt. Some white sublimate began to form. After a total of 45 minutes at 320C., 27 ml. of acetic acid (94% of the theoretical yield) had been collected.

7~3 Vacuumwas then gradually applied and the melt was held at 0.4 mm. for 45 minutes while the temperature was slowly raised to 340C. Foaming again started but gradually died down.
At the end of the heating cycle, the vacuum was released with nitrogen, and the flask was allowed to cool under an inert atmosphere. The polymer formed an opaque viscous melt, pale tan in color, from which long, stiff, strong fibers could be drawn having a"WOody"~ fibrous texture.
When cool, the flask was broken, and the lump of polymer was freed from broken glass, ground in a Wiley mill, and extracted for two hours with acetone in a Soxhlet apparatus to remove traces of monomer, shaft sealing oil, etc.
The polymer exhibited an inherent viscosity of 6.12 dl./g. when measured at a concentration of 0.1 weight/volume percent in penta~luorophenol at 60C. The polymer exhibited double melting temperature peaks at 275C. and 281C. when measured by differential scanning calorimetry.
The powdered polymer was melt-spun as a single filament through a 0.007 inch hole at a throughput rate of 0.14 g./min. and was wound up at 314 m./min. The spin temperature `~ was 330C. The pale cream fibers produced exhibited the following single filament as-spun properties:
Tenacity 12.1 g./d.
Extension 2.3~
Initial Modulus 69~ g./d.
Denier 4.2 7~8 ~ sample of yarn was heated in a relaxed state in a slow stream of nitrogen at 290C. for eight hours. The heat treated yarn exhibited the following properties:
Tenacity 23.4 g./d.
Extension 4.3%
Initial Modulus 652 g./d.

This Example illustrates the preparation of a poly-(ester-amide) from 6-hydroxy-2-naphthoic acid, terephthalic acid, and p-aminophenol (or derivatives thereof) in the ratio 60:20:20.
In the manner described in Example l, a flask was charged with 69.0 g. (0.30 mole) of 6-acetoxy-2-naphthoic acid, 16.6 g. (0.10 mole) of terephthalic acid, and 19.5 g. (0.101 mole) of p-acetoxyacetanilide. 0.02 g. of sodium acetate was added as a catalyst.
The mixture was purged with nitrogen and polymerized in an oil bath as in E~ample l. After 45 minutes at 250C., 16 ml. of acetic acid (56~ of the theoretical yield) had been 20 collected. After 45 minutes at 280C., a total of 24 ml. of acetic acid (84% of the theoretical yield) had distilled. The melt was then heated at 320C. for 25 minutes, by which time 27 ml. of acetic acid (94~ of the theoretical yield)!had been evolved, and the opaque tan melt was quite viscous. Vacuum (20 mm.) was applied slowly and held for 12 minutes at 32QC.
The pressure was then reduced to 0.3 mm. for 18 minutes at 340C. Long stiff fibers could be pulled from the melt.

~ iL7~7~

The polymer was isolated, ground, and extracted as in Example 1. The polymer exhibited an inherent viscosity of 4.24 dl./g., and had a melting temperature (a single DSC peak) at 280C.
The polymer was melt-spun as a single filament through a 0.007 inch hole at 314C. at a throughput of 0.14 g./min. and was wound up at 144 m./min. The fiber exhibited the following as-spun, single ~ilament properties:

Tenacity 9.3 g./d.
Extension 2.0%
Initial Modulus 619 g./d.
Denier 8.8 A sample was heat treated in a relaxed state at 300C.
in a nitrogen atmosphere for 4 hours. The heat treated sample exhibited the following properties:

Tenacity 29.2 g./d.
Extension 6.6%
Initial ~odulus S80 g./d.

EX~MPEE 3 This Example illustrates the preparation of a poly(ester-amide) from 6-hydroxy-2-naphthoic acid, terephthalic acid, and p-aminophenol (or derivatives thereo) in the ratio 50:25:25.

g'7~

The polymer was prepared in the manner described in Example 1. The flask was charged with 57.5 g. (0.25 mole) of 6-acetoxy-2-naphthoic acid, 21.0 g. (0.126 mole) of terephthalic acid, and 24.5 g. (0.127 mole) of p-acetoxyacetanilide. 0.02 g.
of sodium acetate was added as a catalyst.
The polymerization was conducted as in Example 1 using the following heating schedule: 45 minutes at 250C., 45 minutes at 280C., 25 minutes at 320C. A total of 26 ml. of acetic acid (91% of the theoretical yield) was collected. The polymerization was completed under vacuum (0.2 mm.) at 320-340C. for 30 minutes.
The polymer was isolated, ground, and extracted as described in Example 1. The polymer exhibited an I.V. of 5.14 dl./g., and the DSC measurement showed double melting tempera-ture peaks at 325C. (major peak) and 362C.
The polymer was melt-spun at 360C. using a single 0.007 inch hole at a throughput of 0.42 g./min. and a take-up speed of 436 m./min. The fibers exhibited the following as-spun, single filament properties:
Tenacity 10.3 g./d.
Extension 2.2%
Initial Modulus 624 g./d.
Denier 9.4 This Example illustrates the preparation of a poly-(ester-amide) from 6-hydroxy-2-naphthoic acid, terephthalic ~17~

acid, p-phenylene diamine, and hydroquinone (or derivatives thereof) in the ratio of 60:20:5:15.
The polymer was prepared in the manner described in Example 1. The flask was charged with 69.07 g. (0.3 mole) of 6-acetoxy-2-naphthoic acid, 16.61 g. (0.1 mole) of terephthalic acid, 4.85 g. (0.02525 mole) of N,N'-1,4-phenylenebisacetamide, and 14.71 g. (0.07575 mole) of hydroquinone diacetate. 0.01 g.
of sodium acetate was added as a catalyst. After evacuation and purging of the reaction vessel as in Example 1, the vessel was warmed to 250C. using an external oil bath to initiate polymer-ization. Polymerization was conducted between 250C. and 340C.
for 135 minutes under a nitrogen atmosphere and at 340C. and 0.35 Torr for 30 minutes. Upon completion of polymerization, light yellow fibers of moderate strength were pulled from the polymerization vessel as the paddle stirrer was removed. The vessel and its contents were cooled to room temperature. The polymer was recovered, ground, and extracted essentially as in Example 1. The polymer exhibited an I.V. of 4.12 dl./g., and the DSC measurement showed an endothermic transition at 273C.
After drying at about 130C. and 1 Torr for one day, the polymer was melt spun through a 0.007 inch single hole jet within the temperature range of 314C. to 346C., at a through-put within the range of 0.14 to 0.55 g./min., and at take-up speeds as high as 1,162 m./min.
A filament spun at a spinning temperature of 330C., a throughput of 0.52 g./min., and a filament wind-up speed of 1,162 m./min. exhibited the following as-spun, single filament properties:

1~'7~3B

Tenacity 5.98 g./d.
Extension 1.5%
Initial Modulus 543 g./d.
A sample of this monofilament was hea-t treated in a stream o nitrogen at 285C. for 15 hours to give the following properties:
Tenacity 16 g./d.
Extension 3.45%
Initial Modulus 545 g./d.

These Examples illustrate the preparation of a poly(ester-amide) from 6-hydroxy-2-naphthoic acid, dicarboxylic acid, and p-aminophenol (or derivatives thereof). In Examples 5-7, the dicarboxylic acid was terephthalic acid. In Examples 8 and 9, the dicarboxylic acid was 1,2-bis(4-carboxyphenoxy) ethane. In Examples 10 and 11, the dicarboxylic acid was 1,4-cyclohexanedicarboxylic acid (95~ trans isomer).
The polymers were prepared in substantially the same manner as described in Example 1. The final polymerization temperature was usually 340C., except in the case of Example 11 where 320C. was found to be adequate.
Properties and compositions are set out in Table I.

;

, ~

~L7~7~3 TABLE I
Example Composition Molar Ratio T~tOc.) Tg(C.) I.V.(dl./g.) HNA/TA/AAA 70:15:15 293 105 5.89

6 HNA/TA/AAA 80:10:10 360 95 4.27

7 HNA/TA/AAA 65:17.5:17.5 278 93 3.92

8 HNA/CPE/AAA 60:20:20 256 - 3-35

9 HNA/CPE/AAA 50:25:25 256 - 2.62 HNA/CHDA/AAA 60:20:20 185 - 6.47 11 HNA/CHDA/AAA 40:30:30 270 _ 4.80 HNA = 6-acetoxy-2-naphthoic acid TA = terephthalic acid CPE = 1,2-bis(4-carboxyphenoxy)ethane CHDA = 1,4-cyclohexanedicàrboxylic acid (95% trans isomer) AAA = p-acetoxyacetanilide The polymer samples were ground to a coarse powder, ~ extracted with acetone, dried, and then melt~spun through a : single 0.007 inch hole. Spinning conditions and fiber proper-; ties are set out in Table II.

~ -29-~79~

,, ,, ~ U~ o ~ ~, o o o ,, ~ ~ o ~ U~
~ o H ~ --~^
O
a) ,~ ~ o ~ I`
U
~ ~ ~ ~1 .,~ a X ~

~ ^
.,1 .
U ~ ~ ~g u~ ~ In c~ o h N ~ U'l ~ 1~ ~ H
~1 ~ a~
H
H

O ~ ~ I~
a) ~ ~ ~ co c~ o ~ ~1 Q~^
r-~-rl ~ ~ O
O ~
~ O O O O O O O
~ to ~; Q, ,_ .,1 ~ . ~1 ~ O O O O
~ ~9 ~ ~ (~ O 1`
U~ ~ ~ ~7 U~ ~ I` oo ~ O
X

f~

~L~747~3 This Example illustrates the preparation of a poly-(ester-amide) from 6-hydroxy-2-naphthoic acid, terephthalic acid, p-~-methylaminophenol (or derivatives thereof) in the ratio 60:20:20.
The palymer was prepared in the manner described in Example 1. The flask was charged with 69.0 g. (0.3 mole) of 6-acetoxy-2-naphthoic acid, 16.6 g. (0.1 mole) of terephthalic acid, and 21.0 g. (0.101 mole) of p-acetoxy-(N-methyl)-acetanilide. The preparation o~ p-acetoxy-(N-methyl)-acetanilide was accomplished by acetylating p-methylaminophenol with acetic anhydride in pyridine and crystallizing the product from alcohol. The product exhibited a melting point of 98-100C. The components defined above were polymerized in the pr~sence of 0.01 g. of sodium acetate as catalyst.
The flask was purged thoroughly with dry nitrogen and heated for 45 minutes at 250C., 45 minutes at 280C., 30 minutes at 300C., 30 minutes at 320C., and 30 minutes at ; 340C. The total yield of acetic acid was 27.0 ml. (94.4% of the theoretical yield). Polymerization of the opaque, viscous, pale yellow melt was completed under vacuum (0.5 Torr) at 340C.
for 30 minutes. After cooling under nitrogen, the ~lask was broken, and the polymer was recovered. The lumps o~ polymer were ground in a Wiley mill to a coarse powder which was dried in an oven.
The polymer exhibited an I.V. of 1.82 dl./g., and the DSC measuremen~ showed a melting temperature peak at 265C.
The polymer was melt-spun at 392C. through a single 0.007 inch hole at a throughput of 0.42 g./min. and was wound up 1174~

at 75m./min. The resulting fiber exhibited the following as-spun, single filament propertiesO
Tenacity 4.5 g./d.
Extension 1.5%
Initial Modulus 367 g./d.
Denier 58.3 This Example illustrates the preparation of a poly-(ester-amide) from 6-hydroxy-2-naphthoic acid, terephthalic acid, p-N-methylaminophenol, and hydroquinone (or derivatives thereof) in the ratio of 60:20:10:10.
The polymerization was conducted in precisely the same manner as described in Example 12. The polymer melt was an opalescent yellow-brown color, and strong, stiff fibers having a "woody" fra~ture could be pulled from the melt.
The polymer exhibited an I.V. of 1.37 dl./g., and the DSC measurement showed a melting temperature of 280C. The polymer was melt-spun at 331C. through a single 0.007 inch hole at a throughput of 0.14 g./min. and a take-up speed of 319 m./min. The resulting filaments exhibited the following as-spun properties:
Tenacity 8.3 g./d.
Extension 2%
Initial Modulus 506 g./d.
Denier 4.9 -32~

~7~7~

This Example illustrates the preparation of a poly-(ester-amide) from 6-hydroxy-2-naphthoic acid, terephthalic acid, and p-aminophenol (or derivatives -thereof) in the molar ratio 60:20:20.
A 2,000 ml. 3-neck polymer flask was fitted with a sealed glass paddle stirrer, a gas inlet, and a distillation head. A condenser and receiver were fitted to the still head.
Into the flask were placed 414 g. (1.8 moles) of 6-acetoxy-2-naphthoic acid, 99.6 g. (0.6 mole) of terephthalic acid, and 117.0 g. (0.61 mole) of p-aceto~yacetanilide. 0.15 g. of anhy-drous sodium acetate was added as a catalyst. The flask was evacuated and flushed with argon 3 times. The flask was heated under a slow stream of argon in an oil bath to 250C. The contents melted to an opaque slurry and agitation was begun.
Acetic acid began to distill over and was collected in a gradu-ated cylinder. After 45 minutes at 250C., 91.0 ml. (53~
theoretical yield) had been collected. The temperature was then raised to 280C. at which temperature the melt was hea~ed for another 45 minutes, by which time 150 ml. of acetic acid had been collected (87% of the theoretical yield). The temperature was then raised ~o 300C. for thirty minutes, 320C. for thirty minutes, and finally/ 340C. for ten minutes. The final yield of acetic acid was 169 ml. (98.5% of the theoretical yield).
The melt was opaque, dark tan colored, and fairly viscous at this point.

~471~3 Vacuum (0.5 mm.) was slowly applied to minimize the existence of bubbling and foaming of the melt. The melt was held at this pressure for about 20 minutes until the melt became quiescent again. Heating and stirring were then continued under vacuum at 340C. The melt became very viscous and the stirrer motor began to labor. After a total of 45 minutes under vacuum, the system was brought to atmospheric pressure with argon, and the stirrer was pulled from the melt while flushing with a vigorous stream of argon n order to minimize surface oxidation.
Long, strong, stiff fibers were pulled out with the stirrer blade. After cooling under argon, the plug of polymer was removed by breaking the flask and removing broken glass from the ; polymer. Total recovery of polymer was 397.0 g. (88% of the theoretical yield). The plug was sawed up into small chunks and ground in a Wiley* mill into a coarse powder.
The polymer exhibited an inherent viscosity of 6.3 dl./g. when measured in a concentration of 0.1 weight/volume percent in pentafluorophenol at 60~C. The polymer exhibited a glass transition temperature of 110C. and a melting temperature of 280C. when measured by a differential scanning calorimetry.
The polymer was dried for 48 hours at 105C. under vacuum and was then molded on an Arburg* molding machine into test bars under the following conditions:

*Trademark r .

117~t7~

Screw Barrel Temperature 330C.
Mold Temperature 32C.
Cycle Times Injection10 seconds Cooling20 seconds Delay 3 seconds Total 33 seconds Screw R.P.M. 220 Injection Pressure8,000 p.s.i.

~ The molded test bars were tested for tensile strength and modulus according to ASTM D638, for flexural properties in accordance with ASTM D790 and for notched Izod impact strength according to ASTM D256.
The following values were obtained ~average of 5 values):
Tensile Break36,000 p.s.i.
Tensile Modulus 4.4 X 106 p.s.i.
Elongation 1.2~
Flexural Break32,000 p.s.i.
Flexural Modulus 2.2 X 106 p.s.i.
Notched Izod impact strength 5.8 ft.-lbs.

These valu s indicate a remarkable combination of strength and extreme stiffness combined with excellent impact properties.

Although the invention has been described with pre-ferred embodiments, it is to be understood that variations and modifications may be employed as will be apparent to those of ordinary skill in the art. 5uch variations and modifications are to be considered within the purview and scope of the claims appended hereto.

Claims (22)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A melt processable poly(ester-amide) capable of forming an anisotropic melt phase at a temperature below approx-imately 400°C. consisting essentially of recurring moieties I, II, III, and, optionally, IV wherein:
I is ;
II is , where A is a divalent radical comprising at least one aromatic ring or a divalent trans-1,4-cyclohexylene radical;

III is , where Ar is a diva-lent radical comprising at least one aromatic ring, Y
is O, NH, or NR, and Z is NH or NR, where R is an alkyl group of 1 to 6 carbon atoms or an aryl group;
and IV is , where Ar' is a diva-lent radical comprising at least one aromatic ring;
wherein at least some of the hydrogen atoms present upon the rings optionally may be replaced by substitution selected from the group consisting of an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, halogen, phenyl, and mixtures thereof, and wherein said poly(ester-amide) comprises approximately 10 to 90 mole percent of moiety I, approximately 5 to 45 mole percent of moiety II, approximately 5 to 45 mole percent of moiety III, and approximately 0 to 40 mole percent of moiety IV.

2. A melt processable poly(ester-amide) according to Claim 1 which is capable of forming an anisotropic melt phase at a temperature below approximately 350°C.

3. A melt processable poly(ester-amide) according to Claim 2 wherein the molar concentration of moiety II is approxi-mately equal to the total molar concentration of moieties III
and IV.

4. A melt processable poly(ester-amide) according to Claim 1 which comprises approximately 40 to 80 mole percent of moiety I, approximately 5 to 30 mole percent of moiety II, approximately 5 to 30 mole percent of moiety III, and approxi-mately 0 to 25 mole percent of moiety IV.

5. A molding compound comprising the melt processable poly(ester-amide) of Claim 1 which incorporates approximately 1 to 60 percent by weight of a solid filler and/or reinforcing agent.

6. A molded article comprising the melt processable poly-(ester-amide) of Claim 1.

7. A fiber which has been melt spun from the poly(ester-amide) of Claim 1.

8. A film which has been melt extruded from the poly-(ester-amide) of Claim 1.

9. A melt processable poly(ester-amide) capable of forming an anisotropic melt phase at a temperature below approx-imately 350°C. consisting essentially of recurring moieties I, II, III, and optionally, IV wherein:
I is ;

II is , where A is a divalent radical comprising at least one aromatic ring or a divalent trans-1,4-cyclohexylene radical;

III is , where Ar is a divalent radical comprising at least one aromatic ring, Y is 0, NH, or NR, and Z is NH or NR, where R is an alkyl group of 1 to 6 carbon atoms or an aryl group; and IV is , where Ar' is a diva-lent radical comprising at least one aromatic ring, wherein at least some of the hydrogen atoms present upon the rings optionally may be replaced by substitution selected from the group consisting of an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, halogen, phenyl, and mixtures thereof, and wherein said poly(ester-amide) comprises approximately 40 to 80 mole percent of moiety I, approximately 5 to 30 mole percent of moiety II, approximately 5 to 30 mole percent of moiety III, and approximately 0 to 25 mole percent of moiety IV.

10. A melt processable poly(ester-amide) according to Claim 9 wherein the molar concentration of moiety II is approxi-mately equal to the total molar concentration of moieties III
and IV.

11. A melt processable poly(ester-amide) according to Claim 10 which comprises approximately 40 to 60 mole percent of moiety I, approximately 20 to 30 mole percent of moiety II, approximately 5 to 30 mole percent of moiety III, and approxim-ately 0 to 15 mole percent of moiety IV.

12. A melt processable poly(ester-amide) according to Claim 9 wherein each of the moieties of said poly(ester-amide) is free of ring substitution.

13. A melt processable poly(ester-amide) according to Claim 9 wherein said A radical of moiety II is a divalent radi-cal comprising at least one aromatic ring.

14. A molding compound comprising the melt processable poly(ester-amide) of Claim 9 which incorporates approximately 1 to 60 percent by weight of a solid filler and/or reinforcing agent.

15. A molding article comprising the melt processable poly(ester-amide) of Claim 9.

16. A fiber which has been melt spun from the melt processable poly(ester-amide) of Claim 9.

17. A film which has been melt extruded from the melt processable poly(ester-amide) of Claim 9.

18. A melt processable poly(ester-amide) according to claim 1, 2 or 4, wherein moiety II is derived from terephthalic acid, isophthalic acid, or trans-1,4-cyclohexane dicarboxylic acid, moiety III is derived from p-aminophenol, p-N-methylaminophenol, or p-phenylenediamine and moiety IV
is derived from hydroquinone.

19. A process for the preparation of a melt processable poly(ester-amide) as defined in claim 1, which process comprises:
reacting (i) approximately 10 to 90 mole percent of 6-hydroxy-2-naphthoic acid of the formula or a reactive derivative thereof, (ii) approximately 5 to 45 mole percent of a dicarboxylic acid of the formula HOOC-A-COOH

wherein A is a divalent radical comprising at least one aromatic ring or a divalent trans-1,4-cyclohexylene radical, or a reactive derivative thereof, (iii) approximately 5 to 45 mole percent of a compound of the formula H-Y-Ar-Z-H

wherein Ar is a divalent radical comprising at least one aromatic ring, Y is O, NH or NR, and Z is NH or NR, where R is an alkyl group of 1 to 6 carbon atoms or an aryl group, or a reactive derivative thereof, and (iv) approximately 0 to 40 mole percent of an aromatic hydroxy compound of the formula HO-Ar'-OH

wherein Ar' is a divalent radical comprising at least one aromatic ring, or a reactive derivative thereof, until substantially the reaction is completed, wherein at least some of the hydrogen atoms present on the rings optionally may be replaced by substituents selected from the group consisting of an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, halogen, phenyl, and mixtures thereof.

20. A process according to claim 19, wherein the reaction is carried out in the absence of a heat-exchange fluid and in the presence of a catalyst via a melt acidolysis procedure, by first heating the starting materials to form a melt solution thereof and then further heating the solution to form solid polymer particles.

21. A process according to claim 20, wherein (i) approximately 40 to 80 mole percent of a lower acyl ester of 6-hydroxy-2-naphthoic acid, (ii) approximately 5 to 30 mole percent of a dicarboxylic acid selected from the group consisting of terephthalic acid and trans-1,4-cyclohexane dicarboxylic acid, (iii) approximately 5 to 30 mole percent of a compound of the formula H-Y-Ar-Z-H

wherein Ar is p-phenylene radical, Y is 0, NH or NR, Z is NH
or NR, where R is methyl, or a O- or N- or O-and N- lower acyl derivative thereof and (iv) approximat-ely 0 to 25 mole percent of hydroquinone or a lower acyl ester thereof.

22. A process for the preparation of a melt processable poly(ester-amide) as defined in claim 9, which process comprises:
heating a mixture containing (i) approximately 40 to 80 mole percent of 6-hydroxy-2-naphthoic acid 6-acetoxy derivative thereof, (ii) approximately 5 to 30 mole percent of terephthalic acid or trans-1-4-cyclohexane dlcarboxylic acid, (iii) approximately 5 to 30 mole percent of an aminophenol or diamine of the formula, H-Y-Ar-Z-H

wherein Ar is a phenylene or naphthylene radical, Y is O, NH or NCH3, Z is NH or NCH3, or a O- or N- or O- and N- acetyl derivative thereof, and (iv) approximately 0 to 25 mole percent of a diphenol selected from the group consisting of hydroquinone, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenylether, 4,4'-dihydroxydiphenylsulphone, 2,6-naphthal-enediol, 4,4'-dihydroxydiphenylsulfide, 1,2-bis(4-hydroxyphenyloxy)ethane, 1,2-bis(4-hydroxyphenyl)ethane, in the absence of a liquid diluent in the presence of a catalyst to form a melt solution of the starting materials, continuing the heating while removing acetic acid from the reaction system until the polycondensation reaction is substantially completed and solid polymer particles are formed.