WO1991010707A1

WO1991010707A1 - Improved process for forming poly[co(4-oxybenzoate/paraphenyleneisophthalate)] and resulting product

Info

Publication number: WO1991010707A1
Application number: PCT/US1990/006753
Authority: WO
Inventors: Larry F. Charbonneau; Balaram Gupta; H. Clay Linstid; Linda C. Sawyer; James P. Shepherd
Original assignee: Hoechst Celanese Corporation
Priority date: 1990-01-16
Filing date: 1990-11-16
Publication date: 1991-07-25

Abstract

Poly[co(4-oxybenzoate/phenyleneisophthalate)] is formed via the melt-acidolysis polymerization of appropriate monomers under conditions which have been found to substantially alleviate processing difficulties heretofore inherently associated with the biphasic nonuniform nature of such polymer wherein some regions within the polymer form an ordered anisotropic melt phase and other regions form a nonordered isotropic melt phase. The improved process of the present invention is carried out in a stirred heated reactor to which has been added an appropriate minor concentration of a preformed polymer which is capable of forming an anisotropic single phase melt. The desired polymerization is accomplished on a reliable, readily reproducible, and stable basis. A novel relatively inexpensive polymeric composition of matter is provided which is capable of exhibiting an anisotropic melt phase over a broader temperature range and of reliably undergoing melt processing to form quality three-dimensional molded articles because of its modified structural morphology resulting from a diminished biphasic nature.

Description

IMPROVED PROCESS FOR FORMING

POLY[CO (4-OXYBENZOATE/PARAPHENYLENEISOPHTHALATE) ]

AND RESULTING PRODUCT

Background of the Invention

Poly[co(4-oxybenzoate/phenyleneisophthalate)] is a previously known polymer which is disclosed in U.S. Patent No. 3,637,595. However, such polymer is recognized to be difficult to form on a uniform and reliable basis. Such difficulty can be traced to its inherent structural morphology wherein the polymer when melted forms a biphasic melt. Some regions within the melt form an ordered anisotropic melt phase at a given temperature range and other regions form a nonordered isotropic melt phase. The nonuniformity of the product of the prior art also commonly has led to formation of three-dimensional molded articles having widely varying properties. See, (1) "Anomalous

Temperature Dependence of Viscosity of Thermotropic Polyesters", by Gabor Kiss appearing in the Journal of Rheology 30(3), Pages 585 to 599 (1986), and (2)

"Pressure-Induced Phases in a Thermotropic Polyester" by B.S. Hsiao, M.T. Shaw and E.T. Samulski appearing in Macromolecules, 21, Pages 543 to 545 (1988).

Numerous blends of distinct polymeric

materials have been disclosed in the past. However, it has been recognized that the characteristics of the resulting blends commonly cannot be predicted with certainty and require empirical testing since the interaction of the diverse polymer chains within the blend is complex. In U.S. Patent No. 4,267,289 is disclosed a blend of two specific polymers which each form an anisotropic single phase melt. Representative disclosures of polymer blends of an anisotropic melt- forming polymer and an isotropic melt-forming polymer are present in U.S. Patent Nos. 4,228,218; 4,276,397; 4,386,174; 4,408,022; 4,429,078; 4,433,083; 4,442,057; 4,451,611; 4,489,190; 4,567,227; 4,460,735; 4,460,736; 4,611,025; and in European Patent Application Nos.

0170067; 0249226; and 0278066. U.S. Patent No.

4,414,365 discloses a bulk polymerization process for forming an aromatic polyester of a specified formula which may exhibit anisotropic melt properties in the presence of a preformed polymer which is a polyalkylene terephthalate, polyphenylene sulfide, aromatic

polysulfone, or certain oxybenzoyl aromatic polyesters. U.S. Patent No. 4,778,858 discloses a process for preparing a polymer blend composition wherein one forms polyethylene terephthalate in a melt process in the presence of at least one liquid crystalline polymer and subsequently subjects the blend to solid state

polymerization. International Publication No. WO

88/00605 discloses the formation of a specified liquid crystalline polymer in the presence of a preformed poly(aryl ether ketone), poly(aryl ether) or

poly(phenylene oxide).

It is an object of the present invention to provide an improved process for the preparation of poly[co(4-oxybenzoate/ phenyleneisophthalate)] in a stirred heated reactor via a melt-acidolysis

polymerization.

It is an object of the present invention to provide an improved process for the preparation of poly[co(4-oxybenzoate/ phenyleneisophthalate)] wherein the polymerization is accomplished on a reliable, readily reproducible, and stable basis.

It is an object of the present invention to provide an improved process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] which has been found capable of overcoming processing

difficulties normally associated with the biphasic nature of such polymer.

It is an object of the present invention to provide an improved process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] wherein the resulting product exhibits improved melt

processability.

It is an object of the present invention to provide an improved process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] wherein the resulting product exhibits anisotropic melt

properties over a broader temperature range.

It is an object of the present invention to provide an improved process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] wherein the product exhibits enhanced physical and mechanical properties.

It is another object of the present invention to provide a novel relatively inexpensive polymeric composition of matter which is capable of exhibiting an anisotropic melt phase and of reliably undergoing melt processing to form quality three-dimensional molded articles.

It is a further object of the present

invention to provide a novel polymeric composition of matter which is capable of undergoing melt processing to form a three-dimensional article which exhibits a heat deflection temperature of at least 200°C. and a Notched Izod impact strength of at least 1.0 ft.- lb./in.

These and other objects, as well as the scope, nature and utilization of the claimed invention will be apparent to those skilled in the art from the following detailed description and appended claims.

Summary of Invention

It has been found that in a process for the preparation of poly[co(4-oxybenzoate/

phenyleneisophthalate)] in a stirred heated reaction zone via a melt-acidolysis polymerization reaction of appropriate monomers, that improved results are

achieved by providing in the reaction zone during a substantial portion of the polymerization in a well- dispersed form approximately 0.5 to 15 percent by weight of molten preformed polymer which is capable of forming an anisotropic single phase melt with the concentration of the preformed polymer being based upon the total concentration of monomers initially present in the reaction zone.

The resulting novel product possesses an advantageously modified melt morphology and has been found to exhibit significantly improved melt

processability when compared to the poly[co(4- oxybenzoate/phenyleneisophlthalate)] of the prior art. Quality three-dimensional articles can be formed on a reliable basis upon molding.

Brief Description of the Photographs In each instance, samples of the product were prepared for analysis by thin sectioning using a glass knife microtome. The resulting thin sections were held between quartz cover slips and were examined by

standard dynamic thermo-optical polarized light

microscopy to observe morphological behavior at

elevated temperatures. The polymeric sections were heated from room temperature at a rate of 20°C./minute to a maximum temperature of 420°C. followed by rapid quenching. The results were video taped and

micrographs were obtained from the video tape at room temperature (A), 285°C. (B), 345°C. (C), and 395°C.

(D). The magnification was 750X, and the

poly[co(4-oxybenzoate/phenyleneisophthalate] contained 35 mole percent of p-oxybenzoyl units, 32.5 mole percent of 1,4-dioxyphenylene units, and 32.5 mole percent of isophthaloyl units in each instance . The preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] contained 73 mole percent of recurring 4-oxybenzoyl units and 27 mole percent of recurring 6-oxynaphthoyl units.

Figs. 1A, 1B, 1C and 1D illustrate typical sections of poly[co(4-oxybenzoate/

phenyleneisophthalate)] formed in accordance with the prior art. Coarse crystalline and finer liquid

crystalline domains are apparent in the temperature range of 285 (Fig. 1B) to 345°C. (Fig. 1C). At 345°C. liquid crystalline domains are present in an isotropic melt. At 395°C. (Fig. 1D) the melt becomes mostly isotropic and is completely isotropic at 410°C.

Fig. 2 illustrates typical sections of the product of the present invention wherein approximately 1 percent by weight of preformed poly[co(4- oxybenzoate/6-oxynaphthoate)] was intimately admixed with the poly[co(4-oxybenzoate/phenyleneisophthalate)] at the time of its formation. The preformed poly[co(4- oxybenzoate/6-oxynaphthoate)] was intimately admixed with an equal part by weight of poly[co4-oxybenzoate/ oxybenzoate/phenyleneisophthalate)] at the time of its introduction into the reactor. Such intimate admixture was achieved by preliminarily forming the poly[co(4- oxybenzoate/ phenyleneisophthalate)] in the presence of the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] to form a masterbatch. Approximately two parts by weight of this masterbatch were added to approximately 98 parts by weight of the monomers. A finer

microstructure than illustrated in Fig. 1 now is apparent. At 345°C. (Fig. 2C) the texture is finer and has a less coarse crystalling structure.

Fig. 3 illustrates typical sections of the product of the present invention similar to that illustrated in Fig. 2 with the exception that

approximately 4 parts by weight of the masterbatch were added to approximately 96 parts by weight of the monomers, and approximately 2 percent by weight of the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] was intimately admixed with the poly[co(4-oxybenzoate/ phenyleneisophthalate)] at the time of its formation. A further refinement of the microstructure than

illustrated in Fig. 2 is apparent. Additionally, a finer dispersion is clear at 345°C. (Fig. 3C).

Fig. 4 illustrates typical sections of the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)].

Uniform liquid crystalline domains are apparent over the 285 to 395°C. temperature range (Figs. 4B, 4C, and 4D).

Fig. 5 illustrates typical sections of the product of the present invention similar to that illustrated in Figs. 2 and 3 with the exception that approximately 10 parts by weight of the masterbatch were added to approximately 90 parts by weight of the monomers, and approximately 5 percent by weight of the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] was intimately admixed with the poly[co(4-oxybenzoate/ phenyleneisophthalate)] at the time of its formation. A further refinement of the microstructure than illustrated in Fig. 3 is apparent. There is a liquid crystalline texture over the temperature range of 285 to 395°C. (Figs. 5B, 5C, and 5D) which closely

approaches that of the preformed polymer as shown in Fig. 4.

Description of Preferred Embodiments Appropriate monomers capable of forming poly[co(4-oxybenzoate/phenyleneisophthalate)] via a melt acidolysis reaction are provided in a stirred heated reaction zone together with a suitable amount of the molten preformed polymer which is capable of forming an anisotropic single phase melt as described hereafter.

Typical reactants used to form the poly[co(4- oxybenzoate/phenyleneisophthalate)] are phydroxybenzoic acid, hydroquinone and isophthalic acid. Other ester- and amide-forming comonomers (e.g., terephthalic acid, chloroterephthalic acid,

chloroisophthalic acid, phenylterephthalic acid, phenyl-isophthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl sulfone

dicarboxylic acid, 4,4'-biphenol, 4,4'-dihydroxy diphenyl ether, 4,4'-dihydroxy diphenyl sulfone, resorcinol, meta and/or para-hydroxy analine, 4- hydroxy-4'-carboxydiphenyl ether, 2,6- dihydroxynaphthalene, etc., and mixtures of the

foregoing) may be incorporated in the poly[co(4- oxybenzoate/phenyleneisophthalate)] in a minor

concentration of up to 10 mole percent so long as they do not significantly interfere with the achievement of the desired product characteristics. The aromatic rings of the monomers optionally may include substitution of at least some of the hydrogen atoms present upon an aromatic ring 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 (e.g., fluorine, chlorine and bromine), phenyl (including substituted phenyl), and mixtures thereof.

In order for the reactants to undergo the melt-acidolysis reaction it is essential that the reactive hydroxyl groups present thereon first be modified. For instance, the p-hydroxybenzoic acid and hydroquinone reactants may be initially provided in a modified form whereby the usual hydroxyl groups of the monomers are esterified (i.e., they are provided as lower acyl esters). Such lower acyl groups commonly have from about two to about four carbon atoms. Most preferably, the acetate esters of the organic monomer reactants are provided. Accordingly, particularly preferred reactants are p-acetoxybenzoic acid,

isophthalic acid, and hydroquinone diacetate. The acetylation can be carried out in a separate vessel outside the reactor, or such acetylation preliminarily may be carried out in the same reactor through the addition of acetic anhydride prior to the commencement of the polymerization. Conventional esterification catalysts, such as potassium acetate, may be utilized.

In accordance with preferred embodiments the monomers are provided in the reaction zone in

concentrations which yield a poly[co(4-oxybenzoate/ phenyleneisophthalate) which contains approximately 25 to 50 (e.g., approximately 30 to 40) mole percent of recurring 4-oxybenzoate units. As will be apparent to those skilled in the art, the end groups of the

resulting poly[co(4-oxybenzoate/ phenyleneisophthalate) will be influenced by the specific reaction conditions which are selected.

The preformed polymer which is capable of forming an anisotropic single phase melt is provided in the reaction zone in a well-dispersed form in a

concentration of approximately 0.5 to 15 (e.g., 1 to 8, and most preferably 3 to 6) percent by weight with its concentration being based upon the total concentration of monomers initially present in the reaction zone. Such preformed polymer preferably exhibits the single phase anisotropic melt at a temperature within the range of 280 to 340°C. It also preferably is capable of undergoing melt processing at a temperature as high as 340°C. in the absence of significant polymer

degradation. The anisotropic character of the polymer melt may be confirmed by conventional polarized light techniques whereby crossed-polarizers are utilized. More specifically, the anisotropic or ordered nature of the melt phase may conveniently be confirmed by the use of a Leitz polarizing microscope at a magnification of 400 to 750X with the sample on a Leitz hot stage and under a nitrogen atmosphere. The amount of light transmitted changes when the sample is forced to flow; however, the sample is optically anisotropic even in the static state. On the contrary, typical melt- processable polymers do not transmit light in the melt to any substantial degree when examined under quiescent conditions and are isotropic in nature. The single phase nature of the melt may be confirmed by thermal optical microscopy, x-ray crystallography, electron microscopy, polarized light microscopy, differential scanning calorimetry, melt rheology, and other known techniques. Representative classes of polymers from which the preformed polymer may be selected include

anisotropic melt-forming wholly aromatic polyesters, anisotropic melt-forming aliphatic-aromatic polyesters, anisotropic melt-forming poly(ester-amides),

anisotropic melt-forming poly(ester-carbonates), and mixtures of these. In a preferred embodiment the preformed polymer which is capable of forming an anisotropic single phase melt is a wholly aromatic polyester. Also, in a preferred embodiment the

preformed polymer comprises not less than about 10 mole percent of recurring units which include a naphthalene moiety (e.g., a 6-oxy-2-naphthoyl moiety, 2,6- dioxynaphthalene moiety, and a 2,6- dicarboxynaphthalene moiety). The preformed polymer which is utilized preferably exhibits an inherent viscosity of at least 2.0 dl./g. (e.g., 2.0 to 10.0 dl./g/) when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of

pentafluorophenol and hexafluoroisopropanol at 25°C.

The preformed polymers which are capable of forming an anisotropic single phase melt may be selected by those skilled in polymer technology from those known in the art. Preferred polymers which may serve in this role are disclosed in U.S. Patent Nos. 4,161,470; 4,184,996; 4,256,624; 4,330,457; 4,371,660; and 4,473,682, which are herein incorporated by reference.

The preformed polymer which is capable of forming an anisotropic single phase melt is poly[co(4- oxybenzoate/6-oxynaphthoate)]. This wholly aromatic polyester is the subject matter of U.S. Patent No.

4,161,470, and consists essentially of moieties I and II which may optionally include substitution of at least some of the hydrogen atoms present upon an aromatic ring 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 (e.g., fluorine, chlorine and bromine), phenyl (including substituted phenyl), and mixtures thereof wherein: I is , and

II is ,

and comprises approximately 10 to 90 mole percent of moiety I and approximately 10 to 90 mole percent of moiety II. In a preferred embodiment the aromatic rings are substantially free of ring substitution.

Also, in a preferred embodiment the poly[co(4- oxybenzoate/ 6-oxynaphthoate)] comprises approximately 20 to 40 mole percent of moiety I and approximately 60 to 80 mole percent of moiety II. In a particularly preferred embodiment the poly[co(4-oxybenzoate/6- oxynaphthoate)] consists essentially of approximately 27 mole percent of recurring 6-oxy-2-naphthoyl moieties and approximately 73 mole percent of recurring

4-oxybenzoyl moieties. In another particularly

preferred embodiment such polymer consists essentially of approximately 20 mole percent of recurring 6-oxy-2- naphthoyl moieties and approximately 80 mole percent of recurring 4-oxybenzoyl moieties. In preferred

embodiments the poly[co(4-oxybenzoate/

6-oxynaphthoate)] is capable of forming an anisotropic single phase melt at a temperature below approximately 340°C, and most preferably at a temperature below approximately 325°C. It also is particularly preferred that such preformed polymer exhibit an inherent viscosity of at least 4.0 dl./g. (e.g., approximately 5.0 to 7.5 dl./g.) when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of pentafluorophenol and hexafluoroisopropanol at 25°C.

In a preferred embodiment the preformed polymer is formed in the presence of an approximately 0.25 to 4 percent molar excess of an aromatic

dicarboxylic acid monomer and/or an esterified

derivative thereof in accordance with the teachings of U.S. Patent No. 4,539,386 which is herein incorporated by reference. The preferred aromatic dicarboxylic acid is terephthalic acid and the resulting polymer is substantially incapable of further chain growth upon heating.

In a preferred embodiment preformed polymer which is capable of forming an anisotropic single phase melt is preblended and intimately admixed with a quantity of preformed poly[co(4-oxybenzoate/

phenyleneisophthalate)] at the time it is introduced into the stirred heated reaction zone. Such

preblending may be accomplished by physical blending of the molten polymers or by preparing the poly[co(4- oxybenzoate/ phenyleneisophthalate)] in the presence of the preformed polymer which is capable of forming an anisotropic single phase melt. Particularly good results have been achieved when the preformed polymer which is capable of forming an anisotropic single phase melt is preblended with a substantially equal amount by weight of preformed poly[co(4-oxybenzoate/

phenyleneisophthalate)] at the time it is introduced into the stirred heated reaction zone.

During the course, of the melt-acidolysis polymerization in the stirred heated reaction zone it is preferred that a maximum temperature of no more than approximately 350°C. be achieved, and most preferably a maximum temperature of no more than approximately

340°C. This assures that the resulting poly[co(4- oxybenzoate/phenyleneisophthalate)] will not be

subjected to any significant degree of polymer

degradation.

The process of the present invention has been found to be capable of forming poly[co(4-oxybenzoate/ phenyleneisophthalate)] on a more reliable, more reproducible, and a more stable basis than the prior art. Processing difficulties normally associated with the biphasic nature of such polymer are substantially eliminated. The resulting product advantageously is found to exhibit anisotropic melt properties over a broader temperature range than when poly[co(4- oxybenzoate/phenyleneisophthalate)] is formed in accordance with the prior art. Also, the resulting novel composition of matter is capable of reliably undergoing melt processing to form quality three- dimensional articles.

The product of the present invention may optionally incorporate approximately 1 to 50 percent by weight (preferably approximately 10 to 30 percent by weight), based upon the total weight of the polymers, of a solid filler and/or reinforcing agent.

Representative filler materials include calcium

silicate, silica, clays, talc, mica,

polytetrafluoroethylene, graphite, alumina trihydrate, sodium aluminum carbonate, barium ferrite,

wollastonite, etc. Representative reinforcing fibers include glass fibers, graphitic carbon fibers,

amorphous carbon fibers, synthetic polymeric fibers, alumina fibers, aluminum silicate fibers, aluminum oxide fibers, titanium fibers, magnesium fibers, rock wool fibers, steel fibers, tungsten fibers,

wollastonite fibers having an aspect ratio greater than 3 to 1, cotton, wood, cellulose fibers, etc.

In preferred embodiments quality three- dimensional articles are formed upon melt processing which exhibit a heat deflection temperature at 264 psi of at least 200°C. (most preferably at least 220°C), and a Notched Izod impact strength of at least 1.0 ft.- lb./in. (most preferably at least 1.5 ft.-lb./in).

The following Examples are presented as specific illustrations of the claimed invention. It should be understood, however, that the invention is not limited to the specific details set forth in the Examples. Example 1

A cylindrical two liter round-bottomed glass reactor was provided which was equipped with a nitrogen inlet, a thermocouple, Vigreux column attached to a condenser and receiver, and a C-shaped 316 stainless steel mechanical stirrer. The reactor was immersed in a sand bath and provided with means to accurately control the temperature. Into the reactor were placed 290.1 grams (2.1 moles) of p-hydroxybenzoic acid, 218.0 grams (1.98 moles including 0.5 percent molar excess) of hydroquinone, and 324.0 grams (1.95 moles) of isophthalic acid which upon polymerization were capable of forming poly[co(4-oxybenzoate/

phenyleneisophthalate)]. 24.1 grams of preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] while in solid particulate form were added to the reactor. Such preformed wholly aromatic polyester was formed in accordance with the teachings of U.S. Patent No.

4,161,470 and was capable of forming an anisotropic single phase melt. The preformed polymer contained 73 mole percent of recurring 4-oxybenzoate units and 27 mole percent of recurring 6-oxynaphthoate units and exhibited an inherent viscosity of 7.0 dl./g. when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of pentafluorophenol and hexafluoroisopropanol at 25°C. Such preformed polymer was present in the reactor in a concentration of 2.9 percent by weight based upon the total concentration of the three monomers which initially were present in the reaction zone. Additionally, 0.63 grams (75.5 parts per million) of potassium acetate catalyst were added to the reactor. The reactor was under a constant purge of nitrogen at a rate of approximately 30 to 40

c.c. /minute while being charged. The reactor was next evacuated to approximately 1 to 2 mbar two times with the reduced pressure being broken with nitrogen each time.

Acetic anhydride next was introduced into the reactor through an addition funnel in a quantity of 637.4 grams (6.15 moles including a 2.5 mole percent excess). Such acetic anhydride was of 98.5 mole percent purity and was added for the purpose of

converting the p-hydroxybenzoic acid to

4-acetoxybenzoic acid and the hydroquinone to

hydroquinone diacetate prior to the onset of

polymerization.

Through the use of a MicRIcon^® controller the contents of the reactor while stirred were heated in stages as indicated while under a purge of nitrogen at a rate of 30 to 40 c.c./minute.

The acetic acid began distilling-off when the reactor was at 150°C. and at the end of heating stage No. 8 approximately 98 percent of the theoretical amount (687 ml.) had evolved.

At the conclusion of heating stage No. 9 the torque on the stirrer started to rise and an increase in torque of 50 mvolts from the initial value was observed. The reactor was cooled and was opened to obtain the resulting poly[co(4-oxybenzoate/

phenyleneisophthalate)] in which the preformed

poly[co(4-oxybenzoate/6-oxynaphthoate)] was intimately admixed. The polymer admixture was cut and ground into chips to yield 713.2 grams of product (95.8 percent of theoretical).

The resulting product was found to exhibit an inherent viscosity of 0.81 dl./g. when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of pentafluorophenol and hexafluoroiso- propanol at 25°C. The product also was found to exhibit the following properties as determined by standard differential scanning calorimetry at

20°C./min. heating rate:

Melting Point (Tm) = 306°C,

Heat of Melting (Hm) = 6.2 joules/gram,

Glass Transition Temperature (Tg) = 128°C,

Crystallization Point (Tc) = 263°C., and

Heat of Crystallization (Hc) = -8.9 joules/gram. The melt viscosity of the product at 330°C. was 344 poise at a shear rate of 100 sec.^-1, and 112 poise at a shear rate of 1000 sec.^-1. The product when melted exhibited a homogeneous fine uniform microstructure by thermal-optical microscopy and this texture was

retained after quenching at ambient temperature.

While at a temperature of 350°C. the molten product was extruded through a single hole spinneret

(0.005 in. diameter x 0.007 in. at a throughput rate of 0.4 gram/minute). The resulting as-spun filament was quenched in ambient air (25°C. and 65 percent relative humidity) prior to windup at a speed of 705

meters/minute. When a section of the as-spun fiber was examined by optical and thermo-optical microscopy it was found to have an excellent fine uniform

microstructure.

Examples 2 to 16

Example 1 was substantially repeated with the exceptions indicated. More specifically, the molar ratios of the three monomers required to form the poly[co(4-oxybenzoate/ phenyleneisophthalate)] were varied except in Example 2, and in some instances the polymerization heating schedule was varied. In

Examples 5 to 8 Heating Stage Nos. 7 through 9 were carried out at 340°C. instead of 325°C. In Examples 9 to 16 Heating Stage Nos. 7 through 9 were carried out at a temperature of 330°C instead of 325°C. The molar ratios of the monomers and the concentration of the preformed polymer which is capable of forming an anisotropic single phase melt are reported in Table I where Monomer A is p-hydroxybenzoic acid, Monomer B is hydroquinone, and Monomer C is isophthalic acid. The preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] is designated the "Preformed Polymer" and the

concentration is expressed in weight percent based upon the total concentration of monomers initially present in the reactor. Properties of the resulting product also are reported in Table I. With respect to Examples 3 through 8 the melt viscosity measurements were made at 325°C. instead of 330°C. With respect to Example 15 the melt viscosity measurements were made at 340°C. instead of 330°C. With respect to Example 16 the melt viscosity measurements were made at 350°C. instead of 330°C.

It was found that the products of Examples 2 to 16 could be melt extruded as described in Example 1 to form single filaments having an excellent fine uniform microstructure when examined by optical and thermo-optical microscopy.

The remaining portions of the product from the various Examples were combined (e.g., Examples 1 and 2, 3 and 4, etc.) and were compounded while molten with 30 percent by weight of chopped glass reinforcing fibers based upon the total weight of the fibers to form molding compounds. These molding compounds were injection molded to form standard test specimens while using a barrel temperature range of 295 to 320°C. and a mold temperature of 100°C. Tensile tests were

performed in accordance with ASTM D638, flexural tests were performed in accordance with ASTM D790, Notched Izod impact tests were performed in accordance with ASTM D256, and heat-deflection testing was performed in accordance with ASTM D648. The properties of the resulting test specimens are reported in Table II.

For comparative purposes, Example 2 was repeated two times in the absence of the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)]. The identical runs were designated "Comparative X" and "Comparative Y". The properties of the resulting products are not readily reproducible and are reported in Table I.

Also, properties of standard test bars formed while using barrel temperatures of 295°C. and 310°C. are reported in Table II. It will be noted that each of the comparative runs formed products having a

relatively low inherent viscosity of 0.5 dl./g. Also, the glass fiber-reinforced comparative products

following combination and molding exhibited

substantially higher melt viscosities when compared to the values for Example 2.

Examples 17 to 22

Example 1 was substantially repeated with the exceptions indicated. More specifically, the preformed polymer contained 77 mole percent of recurring 4- oxybenzoate units and 23 mole percent of recurring 6- oxynaphthoate units and exhibited an inherent viscosity of 6.8 dl./g. when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of

pentafluorophenol and hexafluoroisopropanol, in

Examples 21 and 22 the molar ratios of the three monomers required to form the poly[co(4- oxybenzoate/phenyleneisophthalate)] were varied, and Heating Stage Nos. 7 to 9 were carried out at 330°C. instead of 325°C. The molar ratios of the monomers and the concentration of the preformed polymer which is capable of forming an anisotropic single phase melt are reported in Table III where Monomer A is p- hydroxybenzoic acid, Monomer B is hydroquinone, and Monomer C is isophthalic acid. The preformed

poly[co(4-oxybenzoate/6-oxynaphthoate)] is designated the "Preformed Polymer" and its concentration is expressed in weight percent based upon the total concentration of monomers initially present in the reactor. Properties of the resulting product also are reported in Table III. Glass fiber-reinforced test specimens were injection molded as described with respect to Examples 2 to 16. The properties of the resulting test specimens are reported in Table IV.

When the resulting products in the absence of the reinforcing fibers were melt extruded to form fibers, the resulting fibers were found via thermo- optical microscopic studies to exhibit an excellent fine uniform microstructure resembling that of the preformed polymer.

Examples 23 to 26

Example 1 was substantially repeated with the exceptions indicated. More specifically, the preformed polymer contained 80 mole percent of recurring 4- oxybenzoate units and 20 mole percent of recurring 6- oxynaphthoate units and Heating Stage Nos. 7 to 9 were carried out at 330°C. instead of 225°C. The preformed polymer was not sufficiently soluble to carry out the standard inherent viscosity determination. The

concentrations of the preformed polymer which is capable of forming an anisotropic single phase melt are reported in Table V where Monomer A is p-hydroxybenzoic acid, Monomer B is hydroquinone, and Monomer C is isophthalic acid. The preformed poly[co(4- oxybenzoate/6-oxynaphthoate)] is designated the

"Preformed Polymer" and its concentration is expressed in weight percent based upon the total concentration of monomers initially present in the reactor. Properties of the resulting product also are reported in Table V. Glass fiber-reinforced test specimens were injection molded as described with respect to Examples 2 to 16. When the glass fiber reinforced products of Examples 23 and 24 were combined, a Notched Izod impact strength of 1.27 ft.-lb./in., and a heat defection temperature of 217°C. were observed. When the glass fiber reinforced products of Examples 25 and 26 were combined, a

Notched Izod impact strength of 0.92 ft.-lb./in., and heat defection temperature of 217°C. were observed.

When the resulting products in the absence of the reinforcing fibers were melt extruded to form fibers, the resulting fibers were found via thermo- optical microscopic studies to exhibit an excellent fine uniform microstructure resembling that of the preformed polymer. nt o

Examples 27 to 34

The preceding examples were repeated in a modified form to demonstrate particularly preferred embodiments of the present invention. In each instance the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] was intimately admixed with preformed poly[co(4- oxybenzoate/phenyleneisophthalate)] at the time of its introduction into the reactor. Such intimate admixture was prepared by preliminarily forming the poly[co(4- oxybenzoate/phenyleneisophthalate)] in the presence of the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] in a manner similar to that previously described to form a uniform masterbatch or master blend of the two polymers. In each instance the masterbatch which was provided in the reactor consisted of equal parts by weight of preformed poly[co(4-oxybenzoate/6- oxynaphthoate)] and poly[co(4-oxybenzoate/

phenyleneisophthalate)]. In all instances the

preformed poly[co(4-oxybenzoate/phenyleneisophthalate)] was formed of monomers which were supplied in the same relative molar concentrations as described in Example 1. In Examples 27 to 30 the poly[co (4-oxybenzoate/6-oxynaphthoate)] contained 73 mole percent of recurring 4-oxybenzoate units and 27 mole percent of recurring 6-oxynaphthoate units. In Examples 31 and 32, the poly[co(4-oxybenzoate/6- oxynaphthoate)] contained 77 mole percent of recurring 4-oxybenzoate units and 23 mole percent of recurring 6-oxynaphthoate units. In Examples 33 and 34, the poly[co(4-oxybenzoate/6-oxynaphthoate)] contained 80 mole percent of recurring 4-oxybenzoate units and 20 mole percent of recurring 6-oxynaphthoate units.

Heating Stage Nos. 7 to 9 were carried out at 330°C. for Examples 27 to 32, and at 340°C. for Examples 33 to 34.

The resulting products were found via thermo- optical microscopic studies to exhibit an excellent uniform microstructure which was of an even finer nature than that achieved in the preceding examples wherein the preformed polymer when introduced into the reactor was not in the form of a master blend. The product of Examples 27 to 30 is illustrated in Figs. 5A, 5B, 5C, and 5D.

In Table VI are reported the concentrations of the masterbatches which were introduced into the reactor expressed in weight percent based upon the total concentration of the monomers which initially are present in the reactor. Table VI also reports

properties of the resulting products. Glass fiberreinforced test specimens of the resulting products also were injection molded as described with respect to Examples 2 to 16. The test results for these test specimens are reported in Table VII.

Examples 35 to 37

Three identical polymerization runs were carried out which were substantially the same as that of Example 1 with the exception that a minor

concentration of an additional comonomer (i.e., 4,4'- biphenol) was charged to the reactor together with the other three monomers.

More specifically, into the reactor were placed 290.1 grams (2.1 moles) of p-hydroxybenzoic acid, 185.0 grams (1.68 moles) of hydroquinone, 324.0 grams (1.95 moles) of isophthalic acid, and 55.9 grams (0.3 moles) of 4,4'-biphenol which upon polymerization were capable of forming poly[co(4-oxybenzoate/

phenyleneisophthalate)] which included a minor

concentration of recurring 4,4'-dioxybiphenyl units. 40.1 grams of preformed poly[co(4-oxybenzoate/6- oxynaphthoate)] while in solid particulate form also were added to the reactor. 0.065 g. of potassium acetate catalyst and 643.8 grams (6.15 moles) of acetic anhydride were added to the reactor. The preformed polymer contained 73 mole percent of recurring 4- oxybenzoate units and 27 mole percent of recurring 6- oxynaphthoate units and exhibited an inherent viscosity of 7.0 dl./g. when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of

pentafluorophenol and hexafluoroisopropanol at 25°C. Such preformed polymer was present in the reactor in a concentration of 4.7 percent by weight based upon the total concentration of the four monomers which

initially were present in the reaction zone.

The properties of the resulting products are reported in Table VIII. Monofilaments were melt extruded at 350°C. from a portion of the product of Example 36. When the resulting fibers were examined by thermo-optical microscopy, fine gels of the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] were observed within a matrix of the poly[co(4-oxybenzoate/

phenyleneiso-phthalate)] containing the recurring

4,4'-dioxybiphenyl units.

The products were compounded with glass fiber reinforcement as described with respect to Examples 2 to 16 and were injection molded to form test specimens using a barrel temperature of 290 to 320°C. and a mold temperature of 100°C. The test results were as follows:

Tensile Strength = 20,500 psi,

Tensile Modulus = 1,840,000 psi,

Elongation = 1.7 percent,

Notched Izod Impact Strength = 1.2 ft.-lb/in., and

Heat Detection Temperature @ 264 psi = 148°C.

Examples 38 and 39

Two identical polymerization runs were carried out which were substantially the same as that of Example 1 with the exception that a portion of the isophthalic acid monomer was replaced by terephthalic acid monomer.

More specifically, into the reactor were placed 304.6 grams (2.205 moles) of p-hydroxybenzoic acid, 228.9 grams (2.079 moles) of hydroquinone, 287.8 grams (1.7325 moles) of isophthalic acid, and 52.3 grams of terephthalic acid which upon polymerization were capable of forming poly[co(4-oxybenzoate/

phenyleneisophthalate)] which includes a minor

concentration of recurring terephthaloyl units. 0.066 grams of potassium acetate and 672.7 grams of acetic anhydride were added to the reactor. 88.1 grams of equal parts by weight of an intimate admixture of preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] and preformed poly[co(4-oxybenzoate/phenyleneisophthalate)] were added to the reactor. Such intimate admixture was prepared by preliminarily forming the poly[co(4- oxybenzoate/phenyleneisophthalate)] in the presence of the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] in a manner similar to that previously described to form a uniform masterbatch or master blend of the two polymers. The preformed poly[co(4-oxybenzoate/6- oxynaphthoate)] contained 77 mole percent of recurring 4-oxybenzoate units and 23 mole percent of recurring 6- oxynaphthoate units and exhibited an inherent viscosity of 5.2 dl./g. when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of

pentafluorophenol and hexafluoroisopropanol at 25°C. The preformed poly[co(4-oxybenzoate/

phenyleneisophthalate) was formed of monomers which poly[co(4-oxybenzoate/phenyleneisophthalate) was formed of monomers which were supplied in the same relative molar concentrations as described in Example 1.

Properties of the resulting product are reported in Table IX. The properties of glass fiber-reinforced test specimens as described with respect to Examples 2 to 16 are reported in Table X.

Examples 40 and 41

Example I was substantially repeated two times with the exceptions indicated wherein a different preformed polymer which is capable of forming an anisotropic single phase melt was substituted for the poly[co(4-oxybenzoate/6-oxynaphthoate)]. Such

preformed polymer was a poly(ester-amide) formed in accordance with the teachings of U.S. Patent No.

4,330,457, and contained recurring 6-oxy-2-naphthoyl units, terephthaloyl units, and p-aminophenoxy units.

More specifically, into the reactor were placed 321.5 grams (2.3275 moles) of p-hydroxybenzoic acid, 241.6 grams (2.1945 moles including a 0.5 percent molar excess) of hydroquinone, and 359.1 grams (2.16125 moles) of isophthalic acid. 52.5 grams of the

poly(ester-amide) which exhibited an inherent viscosity of 4.7 dl./g. when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of

pentafluorophenol and hexafluoroisopropanol measured at 25°C. were added to the reactor together with 0.07 gram of potassium acetate catalyst and 710.1 grams of acetic anhydride. The properties of the resulting products are reported in Table XI. The properties of glass fiber-reinforced test specimens as described with respect to Examples 2 to 16 are reported in Table XII.

Examples 42 to 45

Example 1 was substantially repeated with the exceptions indicated wherein a different preformed polymer which is capable of forming an anisotropic single phase melt was substituted for the poly[co(4- oxybenzoate/6-oxynaphthoate)]. Such preformed polymer which was capable of forming an anisotropic single phase melt was a wholly aromatic polyester formed in accordance with U.S. Patent No. 4,256,624, and

contained recurring 6-oxy-2-naphthoyl units,

terephthaloyl units, and 1,4-dioxyphenylene units. In Examples 42 and 43, the molar ratios of these units were 60:20:20 respectively, and the wholly aromatic polyester exhibited an inherent viscosity of 2.8 dl./g. when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of pentafluorophenol and hexafluoroisopropanol at 25°C. In Examples 44 and 45 the molar ratios of these units were 50:25:25 respectively, and the wholly aromatic polyester

exhibited an inherent viscosity of 6.0 dl./g. prior to being intimately admixed with an equal weight of preformed poly[co(4-oxybenzoate/phenyleneiso- phthalate)]. Such intimate admixture was prepared by preliminarily forming the poly[co(4-oxybenzoate/ phenyleneisophthalate)] in the presence of the

preformed wholly aromatic polyester in a manner

similar to that previously described to form a

masterbatch. The monomers used for preparing the preformed poly[co(4-oxybenzoate/phenyleneisophthalate)] were supplied in the same relative molar concentrations as described in Example 1.

More specifically, in. each of Examples 42 to. 45 to the reactor were added 321.5 grams (2.3275 grams) of p-hydroxybenzoic acid, 241.6 grams (2.1945 moles) of hydroquinone, 359.1 grams (2.16125 moles) of

isophthalic acid, 0.07 gram of potassium acetate catalyst, and 710.1 grams of acetic anhydride. In Examples 42 and 43, 52.6 grams of the wholly aromatic polyester were added to the reactor which provided the preformed polymer in a concentration of 5.7 percent by weight based on the total concentration of monomers present. In Examples 44 and 45, 46.4 grams of the masterbatch were added to the reactor which provided the preformed polymer in a concentration of 2.5 percent by weight based on the total concentration of monomers present. The properties of the resulting products are reported in Table XIII. The properties of glass fiber- reinforced test specimens as described with respect to Examples 2 to 16 are reported in Table XIV.

Examples 46 to 49

Example 1 was substantially repeated with the exceptions indicated wherein a different preformed polymer which is capable of forming an anisotropic single phase melt was substituted for the poly[co(4- oxybenzoate/6-oxynaphthoate)]. Such preformed polymer was a wholly aromatic polyester formed in accordance with U.S. Patent No. 4,473,682, and contained recurring 4-oxybenzoyl units, 6-oxy-2-naphthoyl units,

4,4'-dioxybiphenyl units, and terephthaloyl units. In each of Examples 46 to 49, the molar ratios of these units were 50:10:20:20 respectively, and the wholly aromatic polyester exhibited an inherent viscosity of 4.3 dl./g. when dissolved in a concentration of 0.1 percent by weight of equal parts by volume of

pentafluorophenol and hexafluoroisopropanol at 25°C.

In Examples 46 and 47, into the reactor were placed 274.01 grams (1.995 moles) of p-hydroxybenzoic acid, 205.95 grams (1.8639 moles including a 0.2 mole percent excess) of hydroquinone, 306.04 grams (1.8525 moles) of isophthalic acid, 42 grams of the preformed wholly aromatic polyester, 0.06 gram of potassium acetate catalyst, and 608.1 grams of acetic anhydride. The preformed wholly aromatic polyester was provided in a concentration of 5.3 percent by weight based on the total concentration of the monomers present.

In Examples 48 and 49, into the reactor were placed 260.1 grams (1.89 moles) of p-hydroxybenzoic acid, 195.5 grams (1.7658 moles including an 0.2 mole excess) of hydroquinone, 290.5 grams (1.755 moles) of isophthalic acid, 80.7 grams of an intimate admixture of equal parts by weight of preformed poly[co(4- oxybenzoate/phenyleneisophthalate)] and the wholly aromatic polyester, 0.06 gram of potassium acetate catalyst, and 577.2 grams of acetic anhydride. Such intimate admixture was prepared by preliminarily forming the poly[co(4-oxybenzoate/ phenyleneisophthalate)] in the presence of the preformed wholly aromatic polyester in a manner similar to that

previously described to form a masterbatch. The monomers used for preparing the preformed

poly[co(4-oxybenzoate/phenyleneiso- phthalate)] were supplied in the same relative molar concentrations as described in Example 1. In Examples 48 and 49 the preformed wholly aromatic polyester capable of forming an anisotropic single phase melt was provided in a concentration of 5.4 percent by weight based on the total concentrations of the monomers present.

The properties of the resulting products are reported in Table XV. The properties of glass fiberreinforced test specimens as described with respect to Examples 2 to 16 are reported in Table XVI.

Examples 50 to 53

Example 1 was substantially repeated with the exceptions indicated wherein a different preformed polymer which is capable of forming an anisotropic single phase melt was substituted for the poly[co(4- oxybenzoate/6-oxynaphthoate)]. Such preformed polymer was a wholly aromatic polyester which contained

recurring 4-oxybenzoyl units, 1,4-dioxy-2-phenyl phenylene units, and terephthaloyl units. The molar ratios of these units were 10:45:45 respectively, and the wholly aromatic polyester exhibited an inherent viscosity of 2.7 dl./g. when dissolved in a

concentration of 0.1 percent by weight in equal parts by volume of pentafluorophenol and

hexafluoroisopropanol at 25°C.

In Examples 50 and 51, into the reactor were charged 367.4 grams (2.66 moles) of p-hydroxybenzoic acid, 273.6 grams (2.4852 moles including a 0.2 mole percent excess) of hydroquinone, 410.4 grams (2.47 moles) of isophthalic acid, 61.7 grams of preformed wholly aromatic polyester, 0.08 gram of potassium acetate catalyst, and 811.5 grams of acetic anhydride. The wholly aromatic polyester was provided in a

concentration of 5.9 percent by weight based on the total concentration of the monomers present.

In Examples 52 and 53, into the reactor were charged 348.1 grams (2.52 moles) of p-hydroxybenzoic acid, 259.2 grams (2.3544 moles including a 0.2 mole percent excess) of hydroquinone, 388.8 grams (2.34 moles) of isophthalic acid, 109.8 grams an intimate admixture of equal parts by weight of preformed

poly[co(4-oxybenzoate/phenyleneisophthalate)] and the wholly aromatic polyester, 0.075 gram of potassium acetate catalyst, and 768.8 grams of acetic anhydride. Such intimate admixture was prepared by preliminarily forming the poly[co(4-oxybenzoate/ phenyleneisophthalate)] in the presence of the preformed wholly aromatic polyester in a manner similar to that

previously described to form a masterbatch. The monomers used for preparing the preformed poly[co(4- oxybenzoate/phenyleneisophthalate)] were supplied in the same relative molar concentrations as described in Example 1. In Examples 52 and 53 the preformed wholly aromatic polyester capable of forming an anisotropic single phase melt was provided in a concentration 5.5 percent by weight based on the total concentration of the monomers present.

The properties of the resulting products are reported in Table XVII. The properties of glass fiberreinforced test specimens as described with respect to Examples 2 to 16 are reported in Table XVIII.

Examples 54 to 57

Example 1 was substantially repeated with the exceptions indicated wherein the poly[co(4-oxybenzoate/ 6-oxynaphthoate)] was introduced in two different relatively low concentrations while intimately admixed with an equal part by weight of preformed poly[co(4- oxybenzoate/phenyleneisophthalate)]. Such intimate admixtures were prepared by preliminarily forming the poly[co(4-oxybenzoate/phenyleneisophthalate)] in the presence of the preformed wholly aromatic polyester in a manner similar to that previously described to form a masterbatch. The monomers used when preparing the preformed poly[co(4-oxybenzoate/phenyleneisophthalate)] were supplied in the same molar concentrations as described in Example 1.

In Examples 54 and 55, into the reactor were charged 379.0 grams (2.744 moles) of p-hydroxybenzoic acid, 282.3 grams (2.56368 moles including a 0.2 mole percent excess) of hydroquinone, 423.3 grams (2.548 moles) of isophthalic acid, 20.3 grams of the

masterbatch, 0.082 gram of potassium acetate, and

837.2 grams of acetic anhydride. The preformed

poly[co(4-oxybenzoate/6-oxynaphthoate)] was provided in a concentration of 0.95 percent by weight based on the total concentration of the monomers present. The nature of the product is illustrated in Figs. 2A, 2B, 2C, and 2D.

In Examples 56 and 57, into the reactor were charged 371.3 grams (2.688 moles) of p-hydroxybenzoic acid, 276.5 grams (2.51136 moles including a 0.2 mole percent excess) of hydroquinone, 414.7 grams (2.496 moles) of isophthalic acid, 40.6 grams of the

masterbatch, 0.08 gram of potassium acetate, and 820.0 grams of acetic anhydride. The preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] was provided in a concentration of 1.9 percent by weight based on the total concentration of the monomers present. The nature of the product is illustrated in Figs. 3A, 3B, 3C, and 3D.

The properties of the resulting products are reported in Table XIX. The properties of the glass fiber-reinforced test specimens as described with respect to Examples 2 to 16 are reported in Table XX.

Examples 58 and 59

Example 1 was substantially repeated with the exceptions indicated wherein the preformed poly[co(4- oxybenzoate/ 6-oxynaphthoate)] was prepared in

accordance with the teachings of U.S. Patent No.

4,539,386. More specifically, when the preformed poly[co(4-oxybenzoate/6-oxynaphthoate)] was formed recurring terephthaloyl units derived from terephthalic acid were introduced in a concentration of 3 mole percent together with 78.5 mole percent of 4-oxybenzoyl units and 18.5 mole percent of 6-oxy-2-naphthoyl units. The preformed polymer was not sufficiently soluble to carry out the standard inherent viscosity

determination. The prepolymer was substantially incapable of undergoing additional chain growth upon heating since the polymer chains were caused to

terminate in carboxylic acid end groups during the course of its polymerization reaction.

In Example 58 into the reactor were charged 688.9 grams (4.9875 moles) of p-hydroxybenzoic acid,

513.1 grams (4.65975 moles including a 0.2 mole percent excess) of hydroquinone, 769.4 grams (4.63125 moles) of isophthalic acid, 97.3 grams of preformed poly[co(4- oxybenzoate/6-oxynaphthoate)], 0.6 gram of potassium acetate, and 1521.6 grams of acetic acid. The

poly[co(4-oxybenzoate/6-oxynaphthoate)] was provided in a concentration of 4.9 percent by weight based on the total concentration of monomers present.

In Example 59 the poly[co(4-oxybenzoate/ 6-oxynaphthoate)] was introduced while intimately admixed with an equal part by weight of preformed poly[co(4-oχybenzoate/ phenyleneisophthalate)]. Such intimate admixture was prepared by preliminarily forming the poly[co(4-oxybenzoate/phenyleneisophthalate)] in the presence of the preformed

poly[co(4-oxybenzoate/6-oxynaphthoate)] in a manner similar to that previously described to form a

masterbatch. The monomers used when preparing the preformed poly[co(4-oxybenzoate/phenyleneisophthalate)] were supplied in the same molar concentrations as described in Example 1.

In Example 59 into the reactor were charged 652.7 grams (4.725 moles) of p-hydroxybenzoic acid, 486.1 grams (4.4145 moles including 0.2 mole percent excess) of hydroquinone, 728.9 grams (4.3815 moles) of isophthalic acid, 187.4 grams of the masterbatch, 0.56 gram of potassium acetate, and 1441.5 grams of acetic anhydride. The poly[co(4-oxybenzoate/6-oxynaphthoate)] was provided in a concentration of 5.0 percent by weight based on the total concentration of monomers present.

The properties of the resulting products are reported in Table XXI. The properties of glass fiberreinforced test specimens as described with respect to Examples 2 to 16 are reported in Table XXII.

Although the invention has been described with preferred embodiments it is to be understood that variations and modifications may be employed without departing from the concept of the invention defined in the following claims.

Claims

WE CLAIM :

1. In a process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] in a stirred heated reaction zone via a melt-acidolysis polymerization reaction of appropriate monomers, the improvement of providing in said reaction zone during a substantial portion of said polymerization in a well- dispersed form approximately 0.5 to 15 percent by weight of molten preformed polymer which is capable of forming an anisotropic single phase melt with the concentration of said preformed polymer being based upon the total concentration of monomers initially present in said reaction zone.

2. An improved process for forming poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 1 wherein said monomers consist essentially of p-hydroxybenzoic acid, isophthalic acid, and

hydroquinone wherein the hydroxyl groups are provided as lower acyl esters of 2 to 4 carbon atoms.

3. An improved process for preparing poly[co(4-oxybenzoate/ phenyleneisophthalate)]

according to Claim 1, wherein said resulting poly[co(4- oxybenzoate/ phenyleneisophthalate)] contains

approximately 25 to 50 mole percent of 4-oxybenzoate units.

4. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 1 wherein said preformed molten polymer which is capable of forming an anisotropic single phase melt when introduced into said reaction zone exhibits an inherent viscosity of at least 2.0 dl./g. when

dissolved in a concentration of 0.1 percent by weight in equal parts by volume of pentafluorophenol and hexafluoroisopropanol at 25°C.

5. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 1 wherein said molten preformed polymer which is capable of forming an anisotropic single phase melt is selected from the group consisting of anisotropic melt-forming wholly aromatic polyesters, anisotropic melt-forming aliphatic-aromatic polyesters, anisotropic melt-forming poly(ester-amides), anisotropic meltforming poly(ester-carbonates), and mixtures of the foregoing.

6. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 1 wherein said preformed polymer which is capable of forming an anisotropic single phase melt is provided in a concentration of 1 to 8 percent by weight.

7. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 1 wherein said monomers additionally include up to 10 mole percent of ester-forming monomers which impart other recurring units to said poly[co(4- oxybenzoate/phenyleneisophthalate)].

8. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 1 wherein said preformed polymer which is capable of forming an anisotropic single phase melt is preblended with a quantity of preformed poly[co(4- oxybenzoate/phenyleneisophthalate)] at the time it is introduced into said stirred heated reaction zone.

9. A substantially uniform polymer blend of poly[co(4-oxybenzoate/phenyleneisophthalate)] and preformed polymer which is capable of forming an anisotropic single phase melt formed in accordance with the process of Claim 1.

10. A substantially uniform polymer blend of poly[co(4-oxybenzoate/phenyleneisophthalate)] and preformed polymer which is capable of forming an anisotropic single phase melt formed in accordance with the process of Claim 1 to which has been intimately admixed approximately 10 to 50 percent by weight based upon the weight of the polymers of an additive selected from the group consisting of fillers, reinforcing agents, and mixtures of fillers and reinforcing agents.

11. In a process for the preparation of poly[co(4-oxybenzoate/phenyleneisophthalate)] in a stirred heated reaction zone via a melt-acidolysis polymerization reaction of appropriate monomers, the improvement of providing in said reaction zone during a substantial portion of said polymerization in a well- dispersed form approximately 1 to 8 percent by weight of molten preformed poly[co(4-oxybenzoate/6- oxynaphthoate)] based upon the total concentration of monomers initially present in said reaction zone.

12. An improved process for forming poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 11 wherein said monomers consist essentially of p-hydroxybenzoic acid, isophthalic acid, and

13. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 11, wherein said resulting poly[co(4- oxybenzoate/phenyleneisophthalate)] contains

approximately 25 to 50 mole percent of 4-oxybenzoate units.

14. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 11, wherein said preformed poly[co(4- oxybenzoate/6-oxynaphthoate)] which is introduced into said stirred heated reaction zone exhibits an inherent viscosity of at least 4.0 dl./g. when dissolved in a concentration of 0.1 percent by weight in equal parts by volume of pentafluorophenol. and

hexafluoroisopropanol at 25°C.

15. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 11, wherein said preformed poly[co(4- oxybenzoate/6-oxynaphthoate)] was formed in presence of an approximately 0.25 to 4 percent molar excess of aromatic dicarboxylic acid monomer and/or an esterified derivative thereof and is substantially incapable of additional chain growth upon heating.

16. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 11, wherein said preformed poly[co(4- oxybenzoate/6-oxynaphthoate)] is provided in a

concentration of 3 to 6 percent by weight.

17. An improved process for preparing poly[co(4-oxybenzoate/phenyleneisophthalate)] according to Claim 11, wherein said poly[co(4-oxybenzoate/6- oxynaphthoate)] is intimately admixed with a quantity of preformed poly[co(4-oxybenzoate/phenyleneiso- phthalate)] at the time it is introduced into said stirred heated reaction zone.

18. A substantially uniform polymer blend of poly[co(4-oxybenzoate/phenyleneisophthalate)] and poly[co(4-oxybenzoate/6-oxynaphthoate)] formed in accordance with the process of Claim 11.

19. A substantially uniform polymer blend of poly[co(4-oxybenzoate/phenyleneisophthalate)] and poly[co(4-oxybenzoate/6-oxynaphthoate)] formed in accordance with the process of Claim 11 to which has been intimately admixed approximately 10 to 50 percent by weight based upon the weight of the polymers of an additive selected from the group consisting of

fillers, reinforcing agents, and mixtures of fillers and reinforcing agents.

20. A three-dimensional article formed by the molding of the polymer blend of poly[co(4- oxybenzoate/phenyleneisophthalate)] and poly[co(4- oxybenzoate/6-oxynaphthoate)] wherein said polymer blend was prepared in accordance with the process of Claim 11, wherein the resulting three-dimensional article exhibits a heat deflection temperature of at least 200°C. and a Notched Izod impact strength of at least 1.0 ft.-lb./in.