IE43263B1 - Polyesters derived from dihydric phenols which form anisotropic melts - Google Patents

Abstract

A process for improving the tenacity of a filament having a tenacity of at least one gram per denier and formed from a synthetic linear condensation polymer, characterized in that the polymer is capable of forming an anisotropic melt and that the filament is subjected to heat treatment at a temperature below the flow temperature of the filament and in an inert below the flow temperature of the filament and in an inert a atmosphere and while the filament is in an essentially relaxed condition, the said treatment being conducted until the filament tenacity is improved by at least 50% and exceeds 10 grams per denier. [IN144854A1]

Description

This invention relates to synthetic polyesters. More particularly the invention relates to polyesters in the form of filaments that may be prepared by spinning melts of the polyesters, and that have useful properties, e.g. high strength, which make them particularly interesting for use as industrial filaments, e.g. for reinforcement of tires . The polyesters may also have other uses as shaped, articles.

The preparation of synthetic polyester filaments has been carried out commercially for many years. The basic principles of forming fully synthetic linear polymers were described by W. H. Carothers over 40 years ago, and the commercial preparation of nylon filaments by melt spinning followed. The preparation of poly(ethylene terephthalate) filaments was first disclosed by Whinfield & Dieieson and the commercial preparation of polyesters by melt spinning has essentially followed these same disclosures. For some purposes, it is advantageous to have filaments of extremely high strength. Strength is the property of greatest importance in most Industrial yarns, e.g. for use as tire cord, although other properties also can be of importance. Xt has been possible to improve the tenacity of poly(ethylene terephthalate) filaments by drawing.

Manufacture of typical commercial polyesters suitable for use as tire cord Is discussed by Riggert, Modern Textiles, November 1971, 21-24. An important feature of this manufacturing process discussed by Riggert is the need to use poly(ethylene terephthalate) of high molecular weight and to maintain preorientation of the freshly-spun poly(ethylene terephthalate) at a low level, - 2 « i.e, until solidification and attenuation of the filament is complete. Thus, it is important to delay subjecting the solidifying poly(ethylene terephthalate) filament to the drawing tension until after completion of this stage, and only then to stretch the solidified filament to Induce orientation and increase Its strength. For this reason, If poly(ethylene terephthalate) filaments of high strength are required, poly(ethylene terephthalate) of high molecular weight is spun into a heated zone to delay orientation. Further, to prevent degradation at the high temperatures necessary to lower the melt viscosity to permit extrusion, the polymer is heated first to a lower temperature and is then passed through a special filter leading to the spinning orifices to raise the temperature (by converting mechanical energy into thermal energy) to that desirable for spinning through the orifices to form filaments* This, as can be imagined, takes a lot of time and in spite of all this·treatment, however, it has not been practical commercially to provide poly(ethylene terephthalate) industrial filaments of tenacity much over 10 grams/denier.

It would be desirable to provide synthetic polyester filaments having superior strength properties. It is important that the flow temperature of any such filament be sufficiently high to avoid loss of strength in operation and during processing, and so it would be desirable for such polyesters to have a flow temperature of at least 200°C., preferably at least 250°C.; the term flow temperature, as used herein, Is explained In greater detail hereinafter. It is also important to be able to prepare the polyester filaments by melt spinning, so It i3 desirable that the melting - 3 43263 point of the polyester not be so high as to make melt spinning impractical.

We have now found, according to the present Invention, that it is possible to prepare useful polyesters by polycondensation of dihydric phenols and aromatic or cycloaliphatic dicarboxylic acids to give polymers having flow temperatures of at least 200°C., preferably at least 250°C., and having the property of forming an anisotropic melt from which oriented filaments can be melt spun.

There are provided, therefore, according to the present invention, . polyesters comprising residues of one or more dihydric phenols and of one or more aromatic and/ or cycloaliphatic dicarboxylic acids, having a flow temperature of at least 200°C. and being capable of forming an L5 anisotropic melt from which oriented filaments can be melt spun, with the proviso that there are excludedχί 1) homopolyesters prepared from a dicarboxylic acid containing two rings linked by a chain of four or more chain atoms; (2) homopolyesters prepared from an asymmetrical dicarboxylic acid and an asymmetrical dihydric phenol; and (3) copolyesters prepared from reactants of which 75 mol percent or more are the asymmetrical dicarboxylic acids and dihydric phenols recited in (2).

By “aromatic dicarboxylic acid we mean that each carboxy group Is attached to an aromatic nucleus, as in terephthalic acid, by “cycloaliphatic dicarboxylic acid that each carboxy group is attached to a cycloaliphatic ring, as in 13-cyclohexane dicarboxylic acid, and by “dihydric - 43263 phenol” that each hydroxy group Is attached to an aromatic nucleus, as in hydroquinone. These definitions include thereby compounds wherein the carboxy, or hydroxy groups are attached to different nuclei of a condensed ring system, as in 2,6-naphthalene dicarboxylic acid, or to different ringe that are separated by a direct linkage, as in 4,4’-biphenylene compounds, or by a suitable bivalent radical as in bis(4-hydroxyphenyl)ether, it being understood that proviso (1) should be met; this proviso will be explained hereinafter in greater detail.

In contrast to melt spun filaments of industrial, i.e. high strength, polyesters, principally polyethylene terephthalate), which are spun into filaments in which the polymer molecules immediately become randomly arranged, i.e. unoriented, and which require drawing In order to induce the polyester molecules to become oriented, the polyesters of the invention can be melt spun Into oriented filaments provided that they are subjected to sufficient stretch as they emerge from the spinning orifice, a spin-stretch factor of 10 generally being sufficient. It is believed that this capability of melt spinning to oriented filaments results from the unique nature of the anisotropic melts from which the filaments are melt spun; it is believed that the anisotropic nature of the melt results from the fact that the polyester molecules are in extended chain form and are oriented in local domains of the melt, and that these local domains are oriented during extrusion; and that this orientation persists thereafter. It is generally preferred to spin and wind up at very high speeds for economic reasons, and such speeds In practice - 5 43263 give spin-stretch factors well above 10. At such spinning speeds, we believe that variations in the spin-stretch factor do not make significant differences in the filament orientation, (which would lead to corresponding differences in tenacity of the resulting filaments). This is in contrast to experience with prior polyesters, such as poly-(ethylene terephthalate), where variations in the spin-stretch factor can cause significant differences in the resulting filaments, unless compensated.

Preferred polyesters according to the present invention have the characteristic that filaments, films or other shaped articles formed from them are capable of heat treatment according to the process of our Irish Patent Specification No. of even date herewith, so as to improve their properties significantly, especially their tenacity, tensile strength or impact strength respectively by at least 50%, and preferably severalfold.

It has previously heen suggested, e.g. by Rowland Hill, Fibres From Synthetic Polymers, Elsevier Publishing Company, 1953, that, although the higher the molecular weight of a polymer, the greater should theoretically he the tenacity of its filament, in practice the properties of prior polyester filaments level out as the molecular weight increases. It has not been practical to use polyesters of extremely high molecular weight for making filaments because of their high melt viscosity, as disclosed in U.S. 3,216,187, and the resulting processing difficulties, in conjunction with the tendency of such prior polyesters to degrade at high temperatures such as have been necessary to obtain an extrudable melt. Thus, there has always been, in practice, an optimum molecular weight beyond which it has not been practical to obtain polyester filaments of - 6 43263 Improved tenacity. It has not previou3lyJjeen possible, ' r after spinning commercial polyester filaments, e.g., poly (ethylene terephthalate), from a melt of suitable melt viscosity and molecular weight, to Increase the tenacity significantly by increasing the molecular weight of the polymer in filamentary form. Although it has been possible to increase the molecular weight of poly(ethylene terephthalate) filaments after spinning, the tenacity has not increased significantly. It 13 believed that the effect of this heating has generally been to increase the folding of the molecular chains of poly(ethylene terephthalate) and to decrease the orientation, as mentioned by Wilson, Polymer, Vol. 15, 277-282, May 1974.

In contrast, however, it ls now possible, hy using the polyesters of the present invention, to spin polyesters of suitable melt viscosity into filaments and, thereafter, to increase their tenacity by at least 50% by heating. The increase in tenacity has been accompanied by an increase in molecular weight, and often an Increase in orientation. It ls believed that, with the correct combination of flexibility and stiffness in the molecular chain such that the polymer forms an anisotropic melt, the heating of the as-spun fibers increases the molecular weight of the molecules while maintaining or increasing the overall order and orientation, instead of permitting folding of the molecular chains as apparently occurs in poly(ethylene terephthalate). It is important that the polyester have a flow temperature high enough to permit such heat treatment. It is also important to perform the heat treatment while further polymerization ’ is still possible, because end-capping of the molecules - 7 13 2 6 3 (e.g., by oxidation), seems to affect adversely the possibility of such heat treatment. We prefer to heat treat the filaments at as high a temperature as possible, i.e., as close to the flow temperature as possible, and in practice within about 20°C. below the flow temperature.

If 3uch a heat treatment were to be applied to poly(ethylene terephthalate), the tenacity would decrease rapidly, as shown by Wilson (ibid.). Commercial heat treating temperatures for many of the preferred polyesters of the present invention are expected to be above the melting point of poly(ethylene terephthalate), e.g., In the range of 280-320°C.

An important feature of the present Invention is that It is now possible to melt spin some of the polyester to form L5 filaments that can be heat treated to have tenacities greater than 10 grams/denier. Such polyesters are preferred, especially those that provide filaments that can have significantly higher tenacities, e.g. at least 15 grams/ denier and those that have at least 20 grams/denier. it will be noted that the heat treatment often Increases the modulus, as well as the tenacity of the filaments. Preferred polyesters of the present invention are those that are capable of providing filaments that can be treated to give a modulus of at least 100 grams/denier, and especially those that can give a modulus of at least 300 grams/denier, which is comparable with glass.

This Invention will first be described in relation to the homopolyesters of the present invention, because of their chemical simplicity, and then we shall explain how the composition of the polyesters can be varied to provide - 8 4326 Η·' copolyesters predominantly from dihydric phenols and aromatic or cycloaliphatic dicarboxylic acids to have the same essential and useful characteristics.

We have prepared the following homopolyesters according to the present invention, and therefore present them in the form of a tabular Example to simplify understanding and avoid repetition. The polymerization conditions are conventional, as indicated below, and the importance of the invention lies In the fact that shaped articles, especially oriented filaments of very high strength can be obtained from the melts of such polymers, these melts having the further common characteristics of being anisotropic, and melting in a range that is useful commercially. The melt spinning conditions are conventional, except that, in all the Examples herein, oriented fibers were spun by subjecting the emerging filaments to a spin-stretch factor of over 10. The testing methods are described hereinafter.

The groups in Example 1 are chloro-substituted (A ft B), bromo-substituted (0) and methyl-substituted (D A E) 20 1,4-phenylene rings and are derived by reacting, respectively, the corresponding chloro-, bromo- and methyl-substituted 1,4-phenylene diacetate In equimolar proportions with the appropriate dicarboxylic acid which provides the Rg groups. Pure mono-substituted reactants were used to ensure that the resulting polymers were homopolymers and not copolymers containing a minor amount of diehloro-substituted reactant, for example. The reactants are reacted conventionally, e.g., in a polymer melt tube with a sidearm, a bleed tube for nitrogen or Inert gas, micro-adapter, stirrer and distillate 3° collection tube. The polymerization conditions are as - 9 13263 indicated, e.g., fox’ Example IA the reactor and contents are heated with stirring first at 283°C. for 1 hour (60 minutes) in the presence of anhydrous sodium acetate (catalyst), the acetic acid by-product being distilled off, and then at 283°C. for 10 minutes under a (reduced) pressure of 0.2 mm. Hg and finally at 305°C. for 25 minutes under the same pressure of 0.2 mm. Hg, following which the resulting anisotropic melt is cooled and the polymer is isolated and is found to have an inherent 3-0 viscosity of 3.4 (using solvent 2). The reactants are generally agitated by the mechanical stirrer, especially in the first stage, and/or by passing nitrogen or inert gas therethrough and/or by the passage of by-product which is formed and distils therefrom, especially under reduced pressure. A catalyst is not generally necessary, and was also used only in Examples 5D (antimony trioxide) and 8d and 10A (sodium acetate) hereinafter.

Under the heading Polymerization are given temperature (or range of temperatures) and time(s) of heating, 20 e.g., first at 283°C. for 60 minutes for Example IA, whereas the pressure (mm Hg) is given only if it differs from atmospheric pressure. The inherent viscosity (7?) is measured on the resulting polymer, unless it is indicated by (P) that the measurement was on the filament; the method ,5 and solvent are as indicated hereinafter; insol indicates that the inherent viscosity could not be measured because the polymer did not dissolve In the solvent(s) tried, although solution In other solvent(s) might prove possible. - 10 Γ* β * ί CJ CO Cd CJ cn o vo cn o 1 in o I o KO m cn Cl m f-J CJ cn cn in CJ cj £ o •g ra rd Ch io CJ CJ Ch •=t m cn CJ m 0=1 ί O=V ο I Cl H Ci CJ H K—«· K—* £1 H x—» -5± in d in CO in co •Hi • • • • • e* 1 cn o Ct o Cl [=1 min co o ci m in in ino cj cn in m H ,< o o \\ m in ra o cj m £1 if o (4 co rH Heat Treated Properties s I ri § I fe I σ\ \ rH H ο rH H I t rH co co rH -=t rH ” rH I fe vo \ co vo cu o\ rH θ' fe I c\ vo rH \ in -=± co σν i fe Ol v»/ rH « ίOl vo rH rH O ω a h •H P s £ cd ω .

.H «Ρ cd < ω W in ·» ¢- in rH •l • \ rH 6 rH O • \ O *00· 0 in co^ co ov > tn 01 01 0 01 η ’k-z rH .Q in o- •V *k CO •v • · H OJ A £f* W 0 0 1 \ O in (O O t-vo in rH rH CO rH H 01 01 CO .01 Ol CO to o k O •rl •P 0 JH < Q) 0 n 0 , k fe fe § 1 M l •H ω £ § rH rH fe ΙΟΙ co rH OJ VO σ 0 co’ Ol 01 rH Sw*· v_> vo •01 in rH rH <0 1 1 >1 fe fe I 1 I £ 0 in rH O rH rH rH \ X =t 01 c- « CO 01 in \ vo t- σ\ 0 » • cu cu cu /3.1/189 - F - 17(17.7) 300/4--5(¾) - - 12/4-.7/248 w P H fd 00 fe The heat treatment ia carried out using the following techniques, indicated by the appropriate letter: (a) A skein of yarn ie suspended in a-n oven swept with a continuous stream of nitrogen. The oven and sample are heated through the temperature/time cycle indicated; (b) The yarn Is wound onto a perforated bobbin, that has first been covered with ceramic insulating batting to provide a soft heat resistant surface that yields under low stresses, and is placed In an oven and treated as in (a); (c) Yarn is loosely piled into a perforated metal basket, which Is placed in an oven and treated as In (a), or into a glass tube which is heated through the temperature/time cycle with continuous passage of nitrogen over the filaments.

The temperature/time cycle is indicated in the Table, e.g., in Example IA the oven and sample are heated in nitrogen at 170°C. for 1 hour, then at 230°C. for 1 hour, then at 260°C. for 2 hours and finally at 290“C. for 3/4 of an hour. Generally, the temperature Is changed so rapidly that the oven and sample is at the recorded temperature for substantially the entire period indicated, but lese rapid changes of temperature are Indicated as follows: an arrow, as in Example IB (25-*31θ/θ·7), indicates that the temperature changes less quickly, whereas the word to, as In Example 5C, hereinafter (150 to 160/1.5) indicates that the temperature was within the stated temperature range trending upward, and whereas a dash, as In Example 5A, hereinafter (235-265/1.5) indicates that the ---13263 temperature was changed gradually over the initial 10 to 30 minutes, and then remained at the higher temperature for the rest of the Indicated period. It will be noted that the oven is sometimes allowed to cool and is then reheated, e.g., as in Example 3A, hereinafter.

The heat treatment generally proceeds more expeditiously as the temperature Increases within the desired range, it being usually desired not to operate at a temperature so high that it is impractical to rewind the yarn because 10 of fusion between the filaments. Problems may arise at slightly lower temperatures because of sticking of the filaments, but it is possible to operate at such temperatures if the filaments are precoated with a thin layer of an inert substance, e.g. finely divided talc, graphite or I5 aluminum, and useful results have been obtained by operating in. this way, as was done in Examples 4d and 40.

The continuous purge with nitrogen is extremely Important. The exhaust stream of nitrogen has been found to contain polymerization by-products, such as acetic acid 20 from a 1,4-phenylene-type diaeetate starting material. Thus, it is believed that the heat-treatment causes continued polymerization of the polymer molecules without affecting the shape of the treated article, because the temperature Is below the flow temperature. It is important that these polymerization by-products be removed from the polymer to permit continued polymerization to occur during the heat treating. Other gases that are Inert to the polymer under the heat treating conditions could be used instead of the nitrogen. A convenient way of determining when heat treatment should be discontinued is to monitor the exhaust gas stream for carbon dioxide, or ether decomposition products, and to discontinue tbe heat treatment appropriately, The filaments do not essentially change in length during the heat treatment, in contrast to prior polyesters, which tend to shrink significantly when heated below their flow temperature under similar conditions. Use of bromo-substituted 1,4-phenylene diacetate gave a homopolymer whose filaments did not have particularly high strength as compared with the corresponding chloro-polymer, and is only included to show that it is possible to use a bromo-substituted reactant to get a polymer that will give an anisotropic melt from which orientated filaments can be melt spun, and which filaments can be heat-treated to improve their strength; it is expected that it will be possible to provide significantly stronger filaments from copolymers having bromo-substituents, and the bromo-substituent may impart other interesting properties, such as flame-resistance. The 1,4-phenylen.e diester component may alternatively carry a fluoro substituent although this is comparatively small as compared with a chloro or bromo substituent; an iodo substituent would probably be of too large a size and unstable. Organic substituents that are larger than methyl, e.g. ethyl and methoxy, are too big for use with some diacids, but ethyl is found to be satisfactory in certain combinations. Methyl is a preferred substituent over chloro when better hydrolytic stability is desired; the chlorosubstituted materials can be very useful however.

A preferred set of polyesters comprises those containing recurring units selected from f· OR ·)· and ·(· OC. - Rg - CO )· in equal mole fractions, R^ being selected from chloro-, bromo-, fluoro- and methyl-substituted 1,4-phenylene radicals and R^ is selected from 1,3-phenylene, 1,4-phenylene, dicbloro-1,41 phenylene, 2,6-naphthylene, 4,4 - biphenylylene, trans-1,4cyclohexylene, trans-2,5-dimethyl-l,4-cyclohexylene, oxybis(l,4-phenylene) and ethylenedioxybis-(1,4-phenylene).

For the avoidance of any doubt, linear crystalline polyesters, containing repeating units of the formula:15 -Ο Cl υ O-C OfiH2CIi2O It c— and fibers, films and other shaped articles made from such polyesters, as claimed in British Patent No. 989,552’ claims 13 and 17, respectively, and such polyester and its melt being described in Example 14, are not part of the present Invention. There is no mention in British Patent No.. 989,552 of an anisotropic melt. 1 is doubtful that Example 14 contains sufficient disclosure to teach the preparation of a polyester that is capable of forming an anisotropic melt which can be spun to filaments that are capable of being wound up. It seems likely that the polymer of Example 14 melted with decomposition. There is no mention in Example 14 of the preparation of any shaped articles, such as fibers,’ by melt spinning. The polyester of Example 14 is excluded because it Is a homopolyester prepared from an aromatic dicarboxylic acid containing two aromatic rings linked by a chain of 4 chain atoms. As will be seen herein2Q after, such an aromatic acid, e.g. ethylenedioxy-4,4’-dibensoic acid, is a useful ingredient in a copolyester according to the present Invention, since use of such acid, along with a more rigid acid, such as terephthalic acid, can impart a desirable degree of flexibility to an otherwise rigid polymer molecule. When the homopolymer of the above formula is melt spun, however, tie have not been able to obtain filaments of the very high tenacities or modulus that are obtainable with the copolymers of the invention that are shown in Examples 4A & B hereinafter, even though the filaments were spun from an anisotropic melt that we prepared.

Similarly, homopolyesters prepared from an asymmetrical dicarboxylic acid and an asymmetrical dihydric phenol are excluded, such as are described in British Patent No. 993,272, Which Is directed precisely to the concept of making a crystal5 line polyester from certain selected groups of asymmetrical acids with asymmetrical diols. Not all the claimed groups are exemplified, and the scope of the concept is unclear since the Comparative Examples A & B, which are said not to give crystalline polyesters, meet the requirements of the formulae given in Claims 1, 3 and 6. However specific crystalline doubly asymmetrical homopolyester3 are shown ln Examples 1-3 and 5-10. It is also stated that it is possible to incorporate into the doubly asymmetric polyesters a substantial proportion of a third reactant to give a crystalline product, and Examples 4 and 11-16 show copolyesters from an asymmetrical dihydric phenol with 50 mol percent or more of the diacid reactant being an asymmetrical dicarboxylic acid and the remainder being a symmetrical dicarboxylic acid.

We have found that, when using an asymmetrical dihydric phenol, as is sometimes preferred, it is not possible to use also an asymmetrical dicarboxylic acid, because this introduces an undesirable amount of asymmetry; this leads to difficulties, e.g. in spinning oriented filaments and in obtaining anisotropic melts. None of the homopolymers in Examples 1-3 and 5-10 of British ' Patent No. 993,272 were melted, even at temperatures tp^to 35O°C. Although we exclude copolyesters, such as in Examples 11 and 14, prepared from reactants wherein 50 mol percent of the dicarboxylic acid is asymmetrical and 100 mol percent of the dihydric phenol Is asymmetrical (i.e. 75 mol percent of the reactants are asymmetrical) as required by British Patent No. - 17 43263 993,272, it would obviously be tolerable, although not preferred, to use minor amounts of ε second asymmetrical reactant, such as a methyl-substituted aromatic dicarboxylic acid, even if most or all of the dihydric phenol were also asymmetrical.

The asymmetrical reactants preferred according to the present invention are the mono-substituted dihydric phenols, rather than the dicarboxylic acids.

The notable structural characteristic of the polyesters of the present invention is that in the preferred embodiment of the inve: ion all the molecular units in the polymeric chains comprise ring structures (aromatic or cycloaliphatic). Homopolyesters from unsubstituted inflexible ring structures tend, however,to be too high meltin to be generally useful, e.g. for melt spinning, which is why no such homopolyesters appear in Example 1. We believe that it is imnortant. in order to obtain the useful anisotropic melts fron polyesters of the present invention, to have the stiffness of a chain comprising predominantly aromatic or cycloaliphatic rings, while reducing in a controlled way the melting point to within the range desirable for useful purposes.

We have found that one can achieve this desideratum of desirable melting point, without losing the Btiffness characteristic of such polyesters based on ring structures that is required for anisotropy in the melt, by modifying homopolyesters consisting only of ring structures as follows:(1) Limited substitution of the ring structures, such ae with chlorine and bromine atoms and lower e.g. alkyl groups, this being preferred; and/or (2) Limited copolymerization, i.e., using more than one R^ and/or more than one Rg» this often being preferred; and/or (3) Introduction of limited flexibility between the rings, e.g., by ether linkages and/or aliphatic chains of limited length.

This will now be demonstrated in the following Examples of copolymers following essentially the same format as for Example 1:In Examples 2 and 3A-C, respectively, are shown copolymers derived from chloro-substltuted 1,4-phenylene and from methyl-substituted 1,4-phenylene residues with differing amounts of bis(4-hydroxyphenyl) ether and terephthalic acid; proportions of 60 to 85 mol percent of terephthalic acid give good results, whereas significantly larger or smaller proportions do not give anisotropic melts, or do not give as good filaments. In this Instance, both homopolymers are unsatisfactory; for instance, the homopolyester from chlorosubstltuted 1,4-phenylene diacetate and terephthalic acid melts with decomposition at over 400°C., and cannot be spun by normal melt spinning techniques, and the homopolyester from biB(4-hydroxy phenyl) ether diacetate and terephthalic acid similarly does not melt within a convenient range for meltspinning purposes. Example 3D and 3E, respectively, show similar copolyesters from methyl-Bubstituted 1,4-phenylene residues with terephthalic acid, but the other dihydric phenol residue Is from a naphthalene diol instead of bie(4-hydroxy phenyl) ether.

Example 4 shows copolymers from a substituted 1,4-phenylene diacetate with differing amounts of terephthalic acid and another diearboxylic acid. The substituent on the 1,4-phenylene ring is a chlorine atom in Examples 4A-E, whereas Example 4G uses a raethyl-subsrltuted material and Example 4F uses a dimethyl=substituted material. Example 4H is included merely to show that an ethyl-substituted material can be used, but the tenacity of this material is not particularly Interesting. The tenacities of the other materials made using 2,6-naphthylene-dicarboxylic acid are particularly interesting.

Example 5 shows copolymers of trans-l,4-cyclohexane dicarboxylic acid with residues from more than one 1,4-phenylene derivative. It should be noted that Example 5A contains resi10 dues of three differing, 1,4-phenylene derivatives. Example 5C shows a polyester containing a hydrocarbon linkage between the rings. Example 50 is included to show the use of a tetramethyl-substituted 4,4’-biphenylene derivative; although the final tenacity Is not particularly impressive, this value could probably be improved or higher tenacity filaments could be obtained from other copolymers containing tetramethylsubstituted materials.

Example 6 shows copolyesters that are similar, in that they contain residues of a chloro-substituted 1,420 phenylene ring from the dihydric phenol and of trans-l,4-cyclohexane dicarboxylic acid, but are different in that there are varying amounts of another acid, namely Isophthalic acid. These Examples also show the formation of useful anisotropic melts and filaments therefrom from a polyester comprising a meta-substituted aromatic residue in small amounts. It is believed that up to about 20 mol ? of the meta-substituted aromatic acid would give useful results, and, as indicated in Example 3E, an unsymmetrical naphthalene derivative can give useful results, in amounts as large as 30 mol X of the dihydric phenol. Thus minor amounts of such materials can be tolerated, but it is generally preferred to use materials such as 1,4-phenylene, trans-l,4-cyclohexylene, compounds with 4,4· valences in multi-ring systems, and compounds having their valences parallel and oppositely directed in condensed ring systems, such as 2,6-naphthylene, as indicated in the other Examples.

Examples 7 and 8 show copolymers containing residues of chloro-substituted 1,4-phenylene diol and bis(carboxyphenyl) ether. Example 7 shows a polyester containing residues of another dihydric phenol, whereas Example 8 shows copolyesters containing residues of another dicarboxylic acid.

Example 9 shows copolyesters containing residues from more than one dihydric phenol and more than one dicarboxylic acid. - 21 432 6 3 to Η df* -Ρ ω ο ο ω β ^ Φ W Η 0 in KO t- cn cn tn CM cn 1 t in 1 in tn cn CM K0 M3 tn cn tn cn Ο ο §. £ t ω &t m cn Q\ H cn cn 0 O cn cn cn cn rt- -sf z— it ;=!· S «3 cn »► β r-t KO tn CM •rif • • « rH rH . rH >5=0 Ο I ο ι_L_j g •ri Ρ «β <7Ν \ •ri β S & SΗ ο Ο ρ< ; tn rt ιη § •st (Π ο I · Ο Η 00 I οι σ\ ιη § CM tn ι tn ο · co rt 01 I 00 ·> tn\ tn\ t- 0 rt O tn tn Ol rt rt Ol rH rH \ w tn OO c>.=f 0 tn CO -sf co 01 e φ cm tn CM tp tri co in 0 0 0 M3 t- Ό tn t>- Ol O1 01 01 tn 01 tn o oi in ot o tn 0.40 260-265/65, 275-280/77 1.0(4) 337 370-382 280-325/15 325/34/0.7 to - ?? 43263 IS rH EXAMPLE g CONT'D.

As-Spun Properties Heat Treated Properties Heat Treatment •rl S X s w s o < ϋ o rH rt CM CO \ co tn rt CO S rH rH rt I !» S tn § s H CU l·H i ι o\ & £ CM o cu co cu S I co J=ttn in CM rd H r-i rt X X X X o in o O CM rd o O CO CO tn tn ·» •c ·» rd rd rd rt X X X X o in o O H o σ» CJC 00 oo^ CM -*· CU rd rd OC CM cm cn o o CO rt cm tn I o > in X co rd § x“> z-s x-x t- co o VO it • • • • • s· fc- co CO 0\ rd rd rd rd rd S— X-X SZ s—' CO in O in H H I CO CM I •3* | fo fo 1 fo * fe I fo 1 in CM in 1 in rd o vo t- in co CM cm H X X X X X co O'. co co • • • • « o H CM CM pi X X X X X vo o o co o • • • « • CM in in cn co •ρ»” ο gg tt) Eh Hl C it cn ι sn o cn CO H cn o cn ! VO 1 co cn in p CM CM o cn cn cn b- ί- b- VO 1» cu ο o CM OV m cn co cn CM in co rf- ij- «sfr *—* CM o cn • • H CM rt § *» § •H IL· ω ia O fr $ 'Z co W I O t- in CM · o in ‘Λ •v *v H fr--=f· VO o tn ι JO ΜξΜ vo is* o rH ovo ro o o \ fr- m tn oo cm in cm cn cn cm men 1 1 1 • ' \ in o in in ο o VO CO CM VO co CM CM CM cn cm cm OV os c o in voin OO CO CM cv.cn in in t— i-l « CM · cm in •1 II o tn • CM O in o mm rt CM Η m O in w m in o o CO H CO CM S- H cm cn cu cn cm cn *. «V in - > O' o in vo tn in co σι h CM CM •H CM o its \ \ * O in n CO H tn cm fr- o cm cn m cn CM vo 1 1 X I 1 \ in o in o in o vo co vooo moo CM CM CM CM CM CM I—.....— I $ g o & in i-l o o cn o o o o m cn o o o Ti cd Φ δ ω ο •μ £ =4 * * O AW - 24 43263 EXAMPLE 3 CONT'D.

As-Spun Properties Heat Treated Properties I s cn CO cn rH • in At 9 Ch cn a • Ch rH Ch H H 0) Ch rH rH r-l rH CU CU O p, t*— rH CU w «η g in H J X 1 H ! in : N 1 io N T rH I 1 1 co 1 g co x 1 rH rH rH rt CM rn VO At VO CM H r-t in cu X At X X — in X cn \ CO co X co • vo • • Λ rH • cu cn tn o » CO X CU \ X « CM X in X Ch CO -ri X in • At • cu * rH Ch cn tn H cn H Cl I I · I p· I to rf rt (U O Ρ ϋ cd o $ CM in cu o rH cn o o cn § cn CM •H +> H H rH cn ·» H H X X o o ---^ o O rt cn co- in Λ n * § Η O O in cn cn h CM CM CO * •t n H H r-t X XX O ο o CO CO H CM CM CO CM co *-s CM rH • m • co • cn CO rH H r-t rH s-Z H At tn o N- At rH 1 co g H , m fe ft 1 (it X 1 I fe 1 , rH Ν- 1 in cu vo αό At o rH cu r-t ih tn CU X X X X X At c- t- CO CO rH CM in p rH X X X X X in CM cn CO b~ « • * cn cn co to cu fl O fl W - 25 43263 ΓΜ •Ρ · a) ol k Ο <υ β 0« •ri 9 ft Θ ω Εη ιη co cn co 01 in co cn in I rri cn 01 Oi 1 cn O cn cn cn cn o cn cn co cn cn co cn cn ι vo cn cn ft ci «rt N I rri C β •rl p· in cn in Ol cn vo H Ol Ol cn co o co o O σ\ cn 01 Ol cn Oi co cn 01 *d § Ol cm CM * X_' PQ «*»» • ·' « Jt iri XT J=f- rri rri rri O o 0 vo o vo CO o ω 01 03 * « • • β q β 01 tri tri 0J OJ Η H tri Φ' if o co « ·* ω n ·» nin o ft H β in o X cu X * o Jt o co co rri OI · in in o rri -ri X vo cn *» x Xp cn in β ft •P fc- H X 1 rri X X v fd OJ o in in rri O X oi cn in o 0 N V cn 01 * x S’ rri H in mcu Jt H Jt w •ri β r mo X W OJ 1 X cn m rt 1 1 pLj •ri X 1 1 rri σ\ o in cn o o n • X m on ft a) JS i-l Oi inrt X m o o CM o m cn * ο o mw ώ p£ S \ cn rri · X · m cn ·» cn vo o o m · o ϋ o m o X O CM H \co m mp Tol iri o ·» •>x X o cn i ·» ·> 1 η n invo X XX O o tri cn •V O Jt cn cn co rri ΟΙ 31 VO tri 1 •l *t O 1 -- 1 ft oi cn cnvo cn • .on oi cn -jt- m m in mco oi >— J 1 XXX xx *» rri \\to ^x. X. CM *x *X *x. > = O co in in in in A O\X o ιηχ o o OOO 1 rri cn cn W CM cm CM O o CM CO o m cn o o cn^f 03 JN m cn cn cn cn 5t .tri cn cn h cn cn cn oi cn cn cn •ri ft I 1 1 ( 1 X \\ 1 1 \ 1 1 \\ 1 1 I r in 0 oi cn in o o o in o m o o o in OOO > = o cn cn cn Ο W o cn X 0 01 CO CM O Jt CO r-l cn K 1 O l OJ cn cn cn cn cn cn cn 0J cn cn oi cn cn cn oj cn cn •l o o o o o . o o o *” 1 rri 1 Ol cn cn cn «η m cn cn ,O o 1 _! «, ό 6 6 o ό d o o CO I Pi O o nI o .S’ a o s§* o o Ό ¢4 -P ta C H §1 •P wl fi ta ω o S3 cn —4 « x—-. XX 0 CM X tn ro on r) CM -Tt • ω • • KO H rx -· 00 o rd ft rH r-t CM f; 0 fa- rt CM ro Ch <-» to CM C fa «η 1 J xx 1 P 1 fe ri P Er fe fa fa P fa fa (1) 1 0, l·. 1 1 f-1 -¾ J l o < CM CM t6 tl H m fa in CO cn cm m KO n. CO CM X CM 00 tn KO .co ~-± X X in -=± cn σι Ό X X cn x X ~ it o X X <11 . co KO • it tn it Ch 43 *,·« « w X • • β • nJ X c on in X -=t & on «η it 01 X X in X ?> _ X X I, o co • o in Ό O o CM E-i E-> H H Ch on H r) K CM rH 43 rt I (I) w XX x! β OJ XX XX je P- 1 H 0 ro β 1 XX it in I 1 «Η 43363 β ω •ρ rt <υ to ti Ο .β ^Χ Ρ rt ω fe fe m h ·» *-> fe on • x in 33 * xx J3 o o · **** in ·, ,£} - p * XX \ CM Η H * · in xx mX kO X rH fe rt n cm x\ cn c» * · on ii · · ιηχ £- vx ts ϋ O • X in H H • ο K o o X Η *. 03 CO rH -ft XXX KXX on oj o X ι H cm Cm X cn • ό o xo o i on 00 o ιηχ ι p co ch 0X0 o t CM co m ο o * «β· X X w w vo w ra o m CM H CM fa OM t o w on h n OJ CM H 1 * to . . — on Xx in fe χ 1 χχ1 co m w ra κ -- ra-=t ·» 0 • on tn in * o rl fa vo · · fa * h • fa IT. co - ο o • o o • co X X CM OH ‘CM n w X X oxx P · r-x • p X X O ! » W Λ X o o XO o Xp O 5** fa o o in *x o K ΰ oo σ\ oxo O X XX fa CM xx co in m o fa X w in <0 w w vo w ra o in on o m CM rt · fa ¢0 X · w . . OJ . . m rH ♦ o ·» · . 0 CM *> KWH .ft .ft . On rH on rH fa I t X l rH « 1 It f t 1 t 1 \ 1 fa. fa.1 in ο o 1 VO it1 o o o o1 in o in in o 0 in fa cm o irvit ov it io oo tnvo x η o cm o\ on o on CM H CM o w w w κ w w w w oj cm on m CM cm on fa, X ϊ*, xx 0 XX. CO XX on XX fa 3- XX it • • « • • • « • 00 00 cc fa o KO Ch H H r-t H CM H rH rH XX XX XX kX XX «-Χ ft on σ\ 00 rH rH in a ^f· rH H H CM H cn rt CM ro I I1 1 XX. 1 fa fa fa fe | X 1 1 1 I I it 1 CM m 00 fa •it co in o on H O K w m •st· un in in it it X X X X X X H in co co rl - Ό JS VO • • • « « • O • H CM p H H Κ β H X X X X X X κ X VO X σ\ KO fa in • o • ra X on KO •st it H in ιη • ω 2? °ί Η *2 XX ft in g cm rt to Pm ι ft x w co Λ • o W.O on H Ell $ «! ra ο p Hj Η fe O W ra • Η CM I__ι •P 0 Q) Q fc o Φ β • β a •rl ε Pl <1) to § <υ Η I1-· OS=O o=-o I o o .L hl CM o in in o rH o co cn cn · cn w σ\ σ\ CM rt ·—co CM CM in o rH o in cn co CM cn CM rt Ί—Z *—> < KO CM Jt « • • cn rt CM O CM ·» co • t- O • ·» Ο Ί X o o σ\ο o o CO CM · · rH Jt rt rt h X 1 cn co CO o o co CO CM co co CO rt CM rt · CM Λ CM · CM .i in o in o in o o rt Note - In 5A, Y includes 20 mol % of 2,3-dichloro-l,4-phenylene and 80 mol % of 2,5-dichloro-l,4-phenylene.

X-X X*“X o GO o O • • P b- co a) rH rH X_X \»X o rH rH «} < rH rH fl) O •H 1 1 P 1 f·. fe fe fl) P« fe 1 1 o X tn rH 4“ o O' vo I 4* OJ pi •o X X X 0) °rl to 4 Ol P *.· • • • fl) tn tn 4 fl} M X X X *1 X o in tn H Eh OJ H rH P fl) 1 1 1 4) r~s X OJ C V O' 1 s P O' fe ι § rH X o c CU X P £ 1 tn fl) NS ω 0 P x: E-< X P a a) a> W 0 in ·* χ s*'*'* in · a) • o * • O «Χ-Χ **x ox OJ rH X in X X in co Ol o o w tn oj X in hCO X Ol i o OJ in oi in ι in vo • t in ovo tn oi xi CU n ·* Ο O intnxx 01 OJ '-s •t • · O Ol * If' H H ri in rH a in t— X XX Η P X rH · « o o o β) Ol X Η O vo cu O Ol o XX tn in in oi ri cu p ό φ Ol OJ vo o A · o o •d p V* <01(0 Η p P P 0) «5 rH f 1 1 *x ***s rH Φ X ’ in in O o o o Ο Λ οι in toco χ σι in o O fl) o 01 01 Ol rH OJ ri CU O P CU d to o k φ fl) «Η X— P © P < fl) o P. o 1 b fe fe § Pl 1 w 1 Ή « X < X II X x rH to rH fe ! c rH § BI e>) pj H X 00 X rH ri X_X rH Ol Η H fe fe 5 1 vo σ\ to in cu H X X 4 to ♦ * cu Pi X X co VO Ό to Ch CO ri SH I fe a Ch •η gi sn «η co Η ϊη rd I fo I \ in x tn rt fe ι X rd P g I d a © o £< d 4) W IQ a rl p P. cr ρ fe Ri ω ι tn .fe © •pi HI (Π ιηχ rt · WO . X Ό H t o ®x 1 in rt o ο ω o o in ι o 1 -=3- rt in o rt oi oi in v^· •=t rt I fe I X co tn co rt I fe I rt X § CM - 31 43263 Φ ο φ ί_: . .... ι Η •Ρ • φ Ο fr ο φ β * β Β *Η £ fe φ 03 Β ο ιη CQ ο & ο Η g fe ε ω Β νο Η (Π >5 t r-i φ·3 χ: «Γ σ» :>t=o s = 0 « Ο β Ο •Η •ρ £ as Ν \ τ1 fr «Η Βο° Ο Ρι ν) • « Η Ο Ό Ο \τΙ Μ Ο Η W Ο β \ W ο 01 03 3 · Ο « ·3 \ ΙΛ β Ο t-Hcn ΜΟ co . «01 Μ I -J οιη S- ο isο οι co οι I ιη οι «Τ’ g ο ΡΜ Ο ο S! ail PI Ml EXAMPLE 7 CONT'D.

As-Spun Properties Heat Treated Properties ———————— Heat Treatment Item T/B/Mi - Y/P - OA^arc8) °C ./hours η - T/E/Mi - Y/F - 0A8(arc At trd rH I fe t g rH o a £ «Η in CM rH H CM Ch rH in I § rt <« Ρ φ o Ο Φ β · β 0« •Η Js Ρ< Φ to ΕΗ ο ο * α 01 οι rd Ρ0 .co tn υ ο ο * rt Ρ, a< ε 0) Η κο ο cn ιη ο cn Jt ο co to Η § V <3 rH xi β •Η Γ ci co* ο οι bο to Η ρΓ* β Ο «τΙ ρ g rf ε Ν X. τ’ c *Η ε~χ ho rd ο Ο gU ο—ό ι ©so I Ο β ββ . ° ί S ιη I Jt «η § S co co ιη § ο co nJ Ο CM ο οι ο Νί ο -Ρ» Hi <5 o C0 CO O < © o •H •P 1 © fo fo o X b >< fo 1 TJ © td «Ρ (0 X © w X Ei •P C0 1 δ X β •ri ' «= o S'» • ό Cl x-z X rd rd r~ rd I t I in CJ Ch co st rd rd rd X X X tr. Ch o •s± in vo X X X o in ci rd rd rd1 1 1 ZX r-x Ci CM X-Z x»x 1 -=T • rd CJ © I η) ex •p o d o K © o <0 oi x> ΛΧΖ x*X tn rd CM X *k in Xi o c- x-z O l·- • on «Ρ Cl \ o Ό -s Xx> Ox-· L·- © in Ο rd Ci rd CM CM X * o O O O * t- in O -P m cm CM i'd tx • * rd rd © Ο rt X Xrd X \ in O O S3 in in O CM CM O H 01 g P co I co o rd vo • Z“X • O 0> ¢0 CJ rd rd x-z -=f in rd on · j 1 t Jm N fo I I I o o 3 o o CM rd rt X X X in rd rd Cl cn X X X X rd in σ. on CM 01 £| · «< « HI . 43263 rx β co H «? ta ι +S • 0) O ό £ • £ Oc •rH £ fe Φ ω S Eh O 0 O • rH 0 fe ε φ o At cn vo co cu to rt tn cn H rn x cu CM Jfil £ rH O W £ «Η o co ϋ rl pf1 g c o +5 g N X •H £ £< «Η p fe 1 j f 0=0 O s feH a t O OCILOH 0-©- 295-320/6, 315-320/60, insol. (2) 299 315-322/60/0.1-0.5 (30) CO fe M ! o ii lo] a ei! < HI fl 4326 As-Spun Properties Heat Treated Properties $ I ri § Ci ffl I fl) fr β HX -P O a o ω w w 1 w 1 ft. to I fo 1 CM co 01 \o CO in cn cn o CM co co •rf- co & X X X X X CM b- co CM VO CO co cn in in X X X X X cn H s- co co rH rH rH H ιιι ι i CM rl CM X in tn · t- rl H X. I -rf· in tin w Η ι X in in · t- rl H-X 1 ?· in fr— in CM • I ό ***** CO O ·— •V cm xa X « ΟΙ Xi in CM o in cm — • tn ·» o • in •l p * · J-H co O « · + rH Tit ΟΙ O X X ftl o X in ® on in XX Φ o in ο o SCO XI in in ο o > 00 X> rl CM CO O oi • H CM CO 0 CM *-> Ol Ol XI ., rl rH . CM Ol X) . rH t 1 1 <8 t \ X f ’ 1 a t UV-rf- ' O o1 UV-rf·1 O in t- t- w o co co m t- Ι- (0 Oco CM H Ol «it— CM CM ΟΙ H CM < b CM z*x rH CM rH CM xz z“*fc z—Si g I Jh I Ή £ in UV rl I W I tuv m X CM s in co o oi —-. •rf· rl I w co rH cn fe m O\ X co co oi co co § s |l < « o HI - 37 43263 _ Some of the preferred combinations that have been disclosed herein include polyesters of general forraula:0 0 n ti [-0-Rj-.0-.C-.R2-C-] 5 wherein -0-R^-0- is a divalent radical from a dihydric phenol, 0 η n and -C-Rg-C- ia a divalent radical from an aromatic or cycloaliphatic dicarboxylic acid, as follows:I - 95 mol % or more of the Rx radicals are chloro10 substituted 1,4-phenylene and 95 mol i or more of the Rg radicals being trans-1,4-cyclohexylene, e.g,, polyfchloro1.4- phenylenetrans-l,4-cVclohexane dlcarboxylate)j II - Rg is oxybis (1,4-phenylene), and Rj is selected from chloro- and methyl-substituted 1,4-phenylene, e.g., up to 20%, of bromo-l,4-phenylene and up to 10 mol 3» of the total of the Rj and R2 units optionally bs replaced, i.e., up to 20 mol % of Rj being replaced by 1,4phenylsne, dichloro-l,4-phenylene, 4,4’-biphenylene, oxy-1,4-. diphenylene, thio-l,4-diphenylene or 3,3*,5,5’-tetramethyl20 4,4’-biphenylene, and/or up to 20 mol ί of R2 being replaced by 1,4-phenylene, 1,4-cyelohexylene, 2,6-naphthylene, 4,4’biphenylene or ethylene dioxy di-l,4-phenylene, or less prefereably 1,3-phenylene, chloro- and/or bromo-substituted 1.4- phenylene; III - Rg being 20-80 mol i bis(4-phenyleneoxy)ethylene and 80-20 mol ί selected from 1,4-phenylene, 1,4-cyclohexylene and 4,4’-biphenylene, and Rj being 20-100 mol i selected from methyl- and chloro-substituted 1,4-phenylene, and up to 80 mol 35 1,4-phenylene; IV - being the range of copolymers shown In Examples 2 and 3, - 38 43 2 R^ being 85-60 raol preferably 70 mole X, chloroor methyl-substituted. 1,4-phenylene and 15-40 mol ¢, preferably 30 mol tt is oxy-bis (1,.4-phenylene) ether and Rg is' 1,4-phenylene; and V - Rg being 20-80 mol ί ot 1,4-phenylene and 80-20 mol % 4,4’-biphenylene and/or 2,6-naphthylene and/or l,4’-cyclohexylene and/or oxy-bis(1,4-phenylene), and Ri being chloroor methyl-substituted 1,4-phenylene or less preferably bromo1,4-phenylene.

Xt Is evident from the large number of copolyesters exemplified that many further variations are possible.

Although commercial considerations will probably dictate a preference for using comparatively simple and/or inexpensive reactants ln relatively simple combinations, it should be recognized that the present invention is based on the discovery of polyesters having fundamentally new properties, and it is predictable that particular combinations that have not been disclosed precisely herein will have interesting and useful properties.

The following articles other than filaments have been made:A - A strong film having an edge orientation angle of about 20° was prepared from an anisotropic melt of poly(chloro-1,4-phenylene trans-l,4-cyclohexane-dicarboxylate) by melt extrusion at 303-310°C. in a Sterling extruder through a slot of dimensions 3 ins x 3 mils (8cm. x 0.08 mm.) onto a casting drum, quenched ln water and wound up. After heat treatment in a stream of nitrogen at 170°C./3 hours, 230eC./ l6 hours, 26o°C./22 hours, 285°c./7 hours and 260°/64 hours, the cooled film was of thickness 0.04 mm. and had tensile 1263 strength/elongation/modulus of 110,000 psi/3.5%/2,950,000 psi (7,700 kg/sq.cm„/3.5^/207,000 kg/sq.cm} B - Bars molded from polyesters of the invention have shown good properties of stiffness, as measured by flexural modulus (FM) and toughness, as measured by notched Izod impact strength (ni), e.g. bars of poly(chloro-1,4-phenylene 1,4-cyclohexane-dicarboxylate) have shown a FH of 580,000 pai (41,000 kg./sq.cm) and a ni of 2.2 ft.lb./in. (0.12kg. cm./cm.).

Wie characteristics referred to herein were measured as follows:Optical Anisotropy - TOT (Thermo-optical test) It is well known that translucent optically anisotropic materials cause polarized light to be transmitted in optical systems equipped with crossed polarizers, whereas transmission of light should theoretically be zero for isotropic materials under the same conditions. The following thermo-optical test (TOT) uses this feature to Identify anisotropic polyester melts according to the present invention with an apparatus that is essentially similar to that described by I. Kirshenbaum, R. B. Issacson, end W. ¢3. Feist, Polymer Letters, 2 897-901 (1964), but uses apparatus units that are available to us.

She thermo-optical test (TOT) requires a polarizing microscope which should have strain-free optics and sufficiently high extinction with crossed (90°) polarizers to be capable of giving a background transmission specified below. & Leltz Dialux-Pol microscope was used for the determination reports herein. It was equipped with Polaroid (Registered Trade Mark) polar30 izers, binocular eyepieces, and a heating stage. A photodetector was attached at the top of the microscope barrel. The microscope had a 32.X, long working distance objective, and a Red I plate (used only when making visual observations with crossed polarizers; inserted at an angle of 45° to each polarizer).

Light from a light source is directed through the polarizer, through the sample cn the heating stage and through the analyzer to either the photodetector or the eyepieces. A slide permits transferring the image from eyepieces to photodetector. The heating stage used Is one capable of being heated to 500°C.. A Unitron model MRS vacuum heating stage (Unitron Instrument Co., 66 Needham St,,, Newton Highlands, Massachusetts 02163) was used. The photodetector signal is ampllf .ed aid fed to the Y-axis of an X-Y recorder. T'he system response to light Intensity should be linear and the error of measurement within + 1 mm on the chart paper. The heating stage is providad with two attached thermocouples. · One Is connected to the X-axis of the X-Y recorder to record Btage temperature, the other to a programmed temperature controller. Tlie microscope is focused visually (with crossed polarizers) on a polymer sample prepared and mounted as described below. The sample, but not the cover slip, is removed from the optical path. The Polaroid analyzer of the microscope is removed from the optical path, the slide is shifted to transfer the Image to the photodetector and the system i3 adjusted so that full-scale deflection (13 cm on the chart paper used) on the Y-axis of the X-Y recorder corresponds to 36? of the photometer signal. The background transmission value is recorded with crossed (90°) polarizers and with the cover slip, but not the sample, In the optical path. The background transmission in the system used should -41 ϊ independent of temperature and should be less than about ,5 cm on the chart paper.

The sample is preferably a 5u section microtomed Ith a diamond knife from a solid well-coalesced chip of pure >lymer (e.g., as prepared In the Examples), mounted in joxy resin. A less preferred method, but one especially seful for low molecular weight materials that shatter when lerotomed, Is to heat on a hot plate a sample of finely Ivided polymer on a cover slip resting on a microscope slide, le hot plate temperature (Initially about 10°C. above the >lymer flow temperature) is increased until the polymer just talesces to a thin film essentially equivalent In thickness ι the microtomed sections, I.e.„ about 5w.

The sample section Is pressed flat between cover .ips. One cover slip Is removed and the sample on the gaining cover slip is placed (glass down) on the heating age. The background transmission is measured, and the mple Is positioned so that essentially all the light Interpted by the photodetector will pass through the sample, th the sample between crossed (90°) polarizers and under trogen, the light Intensity and temperature are recorded on e X-' recorder as the temperature is raised at a programmed te o.’ about l4°C/mln from 25° to 450°C. The sample temperare Is obtained from the recorded temperature by use of a itable calibration curve.

The use of the TOT test will be further described th reference to the accompanying drawing in which are own traces of light intensity plotted against temperature r poly(ethylene terephthalate) which forme an Isotropic It (Curve A) in contrast to a polyester of the invention, poly(chloro-1,4-phenylene trans-l,4-cyclohexanedlcarboxylate) which forms an anisotropic melt (Curve B).

The intensity of light transmitted through the analyzer when isotropic melts (the sample should be completely melted) are placed between crossed (90°) polarizers is essentially that of the background transmission (that obtained when the sample but not the eover slip is outside the field of view with 90° crossed polarizers). As the melt forms, the intensity of the light transmission (1) Is either already essentially that of the background transmission or (2) decreases to such values from a higher xralue as in Curve A of the Figure, which illustrates an intensity trace of poly(ethylene terephthalate), which forms an isotropic melt.

The polyesters of the present invention are considered to form anisotropic melts If, as a sample is heated between crossed (90°) polarizers to temperatures above its flow temperature, the intensity of the light transmitted gives a trace on the recorder chart whose height is--at least twice the height cf the background transmission trace and is at least 0.5 cm greater than the background transmission trace. As these melts form, the value (height) of the light transmission trace (1) is at least 0.5 cm greater than that of the background transmission, and Is at least twice that of the background, or (2) Increases thereto. Curve B of the Figure is of type (2) and Illustrates the type of Intensity trace usually obtained for systems forming anisotropic melts of the polyesters according to the present invention.

The polyesters of this invention often exhibit optical anisotropy throughout the temperature range tested, I.e., from the flow temperature to the decomposition - 43 - temperature of the polymer or the maximum test temperature (450°C.). However, for.some polyesters, portions of the melt may become isotropic when the melt begins to decompose thermally. For still other species, the character of the melt may change completely from anisotropic to isotropic with increasing temperature. inh (Inherent viscosity) - was determined as in U.S. Patent 3,327,998 but with these solvent systems (proportions by volume):10 (1) 60? trifluoroacetic acld/40? methylene chloride (IB) 30? trifluoroacetic acid/70? methylene chloride (2) ls3-dichloro=l,lj,3,3-fcetrafluoroacetone hydrate (3) 50? solvent (2)/50? perchloroethylene (4) p-chlorophenol (5) 15% trifluoroacetic acid/35% methylene chloride/ ? solvent (2)/25% perchloroethylene (6) 50? solvent (5)/5O? solvent (4) The range of suitable inherent viscosities will depend greatly on the flexibility of the polymer molecules, 20 and inherent viscosities are only pertinent to soluble polymers. Polymers of inherent viscosity as low as 0.3 could be useful, e.g. as coatings. For soluble polymers, inherent viscosities should generally be lower than 4.0, for ease of processability, As is well known, excessively high melt viscosities gives processing problems, e.g. in melt spinning filaments. Insoluble filaments that flow within the indicated ranges of flow temperature could prove useful commercially.

Flow Temperature - This is the temperature at which the polymer flows. As the melt viscosity Increases, - 44 4 326L this Is Manifest by the sharp edges of a tiny chip of polymer or of a cut fiber becoming rounded. The flaw teaperature ls determined by visual observation of the sample on a cover slip placed between crossed (90°) polarizers on the heating stage assembly described herein for the TOT procedure. A suitable heating rate is usually l4°C./Mln, but, In a few cases, where rapid further polymerization occurs, a faster rate, about 50°C./mln., Is used.

The flow teaperature of any particular saaple will depend on Its history. For example, shaped articles sometimes have flow temperatures different from the polymer from which the article has been shaped; stepwise heating ordinarily raises the flow temperature, and permits progressively raising the temperature of heat treating to above the Initial flow temperature, as shown ln some of the Examples.

For processability, the polyesters should flow at temperatures below those at which rapid decomposition occurs, otherwise plasticizers, solvents or other techniques would be necessary to provide the desired shaped articles. Although it may be practical to process some polyesters with flow temperatures as high as 450°C., for example, the flow temperature should preferably be less than 400°C., e.g. ln the range of 2OO-37O°C., especially from 250-350°C.

The spin-stretch factor ls the ratio of the velocity of the extruded yam (measured at wind-up) to the velocity of the melt through the spinneret, the latter being the volume of melt extruded per minute divided by (the crosssectional area of each hole x the number of holes).

Filament Properties - These are given for both - 45 43263 as-spun filaments and heat-treated filaments. The tensile properties were measured as in U.S. No. 3,827,998, and the MYn or nF indicates whether the properties of a multifilament yarn or a filament were measured. OA*(arc°) indicate the orientation angle and (26 specific arc) as in U.S. 3,671,542, and were measured by method (2) therein.

Claims (2)

1. CLAIMS i 1. Polyesters, comprising residues of ana or more dihydric phenols and of one or more aromatic and/or cycloaliphatic dicarboxylic acids, said polyesters having a flow temperature of at loast 200°C and being capable of forming anisotropic melts from which oriented filaments can be melt spun, with the proviso that there are excluded: (1) homopolyesters prepared from a dicarboxylic acid containing two rings linked by a chain of four or more chain atoms; 2. (2) homopolyesters prepared from an asymmetrical dicarboxylic acid and an asymmetrical dihydric phenol; and (')) cope l.yesters prepared from reactants, of which 75 mol percent or more art: the asymmetrical Jicarboxvlic acids and dihydric phenols recited in (2).

2. Polyesters as claimed in claim i, wherein all the residues between the ester linkages comprise ring structures, some of the rings being substituted with chlorine and/or bromine atoms and/or $ alkyl groups. '1. Polyesters as claimed in claim 2, wherein the said substitution is on an aromatic ring. 4. Polyesters as claimed in claim 3, wherein the said substitution is on the residue of a dihydric phenol. 5. Polyesters as claimed in any of claims 2-4, having ether linkages between some of the rings. 6. Polyesters as claimed in any of claims 2-5, havingchains containing aliphatic groups between some of the rings. 7. Polyesters as claimed in any of the preceding claims which are copolymers. 8. PoLvesters as claimed in any of the preceding claims containing ring structures substituted with chlorine. 9. Polyesters as claimed in any of claims 1-7» containing ring structures substituted with Calkyl groups. - 47 43263 10. Polyesters as claimed in claim 9, containing ring structures substituted with methyl groups. 11. Polyesters as claimed in any of claims 1-7, containing ring structures substituted with bromine. 5 12. Polyesters as claimed in claim 1 containing recurring units selected from OR^O ·)· and OC. - Rg - CO ·)· in equal mole fractions, R^ being selected from chloro-, bromo-, fluoroand methyl-substituted, 1,4-phenylene radicals and R o is , selected from 1,3-pbenylene, 1,4-phenylene, dichloro-1,4LO phenylene, 2,6- naphthylene, 4,4 - biphenylylene, trans-1,4cyclobexylene, trans-2,5-dimethyl-l,4- cyclohexylene, oxybis(1,4-phenylene) and etbylenedioxybis -(1,4-pbenylene) . 13. Polyesters as claimed in claim 12, wherein 95 mol$ or more of the R^ radicals are chloro-substituted 1,4-phenylene 5 and 95 mol^ or more of the Rg radicals are trans-1,4-cycloboxyleti 14. Polyesters as claimed in claim 12, wherein Rg is oxybis-(l,4—phenylene) and R^ is selected from chloro-, bromoand methyl-substituted 1,4-phenylene, up to 10 mol % of the total of the R^ and Rg units optionally being replaced, up to θ 20 mol ‘fa of R^ being replaced by 1,4-phenylene, dichloro-1,4phenylene, 4,4 - biphenylene, oxy-l,4-diphenylene, thio-1,4diphenylene or 3,3 , 5,5 - tetramethyl-4,4 - biphenylene, and/or up to 20 mol fa of Rg being replaced by 1,4-phenylene, 1,4cyclobexylene, 2,6-naphthylene, 4,4 -biphenylone, 5 ethylenedioxy di-1,4- phenylene, 1,3-phenylene, chloroand/or bromo-substituted 1,4-phenylene. 15. Polyesters as claimed in claim 12, wherein 20-80 mol % of Rg is bis-(4-phenyleneoxy) ethylene and 80-20 mol fa ia selected from 1,4-phenylene, 1,4- cyolohexylene and 4,4 ' biphenylene, and 20 - 100 mol fa of R^ is selected from methyland chloro-substituted 1,4-phenylene, and up to 80 mol fa is 1,4phenylene . - 48 43263 16. Polyesters as claiined in claim 12, wherein 85 - 60 mol 56 of R^ is chloro-or methyl-substituted 1,4-phenylene and 15 - 40 mol 56 is oxy-bis-( 1,4-phenylene) and 11^ is 1,4-phenylene. 17. Polyesters as claimed in claim 12, wherein 20 - 80 5 mol % of Rg is 1,4- phenylene and SO - 20 mol $ is 4,4 biphenylene and/or 2,6-napbthylene and/or 1,4-cyclohexylene and/or oxy-bis-(l,4-phenylene), and Rj is chloro-, bromo- or methyl-substituted 1,4-phenylene. 18. Polyesters as claimed in any of claims 1-11 and. 13-16 10 which, in the form of filaments, are capable of heat treatment to improve their tenacity by at least 5°'/· 19. Polyesters as claimed in either of claims 12 or 17 which, in the form of filaments, are capable of heat treatment to improve their tenacity by at least 15 20. Polyesters as claimed in claim 1 hereinbefore specifically mentioned. 21. Polyesters as claimed in claim 12 substantially as described in Examples 1 - A, 1 - Β, 1 - C, 4 - C, 4 - D, 5-A, 5 - B, 5 - D and 8 - A. 2 0 22. A process for preparing polyesters as claimed in any of the preceding claims, wherein the dihydric phenol(s), and/or derivative(s) thereof, is (are) reacted with the aromatic and/or cycloaliphatic dicarboxylic acid(s), and/or derivative(s) thereof, until the desired polymer is formed. 25 23. A process as claimed in claim 22, wherein reaction is continued until the polymer reaches an inherent viscosity of at least 0.3. 24. A process as claimed in claim 22 or claim 23, wherein reaction produces a polyester as claimed in claim 12 or claim 17. 25. A process as claimed in claim 22 substantially as hereinbefore described. 26. A process as claimed in claim 22 substantially as hereinbefore described with reference to the Examples. - 49 43263 27. A process as claimed in claim 24 substantially as hereinbefore described with reference to Examples 1 - A, 1-D, 4 - C, 5-B and 5 - D. 28. Polyesters prepared by the process either of ciaim 22 or claim 23. 29. Polyesters as claimed in any of claims 1 - 21 or 28 in the form of a shaped article. 30. Polyesters prepared by the process of either of claims 24 or 2731. Polyesters as claimed in any of claims 12,17,19, 21 or 30 in the form of a shaped article, 32. A shaped article filament. as claimed in c laim 29 which is a 33· A shaped article filament. as claimed in claim 31 which is a 34. A shaped article of a sheet-like structure. as claimed in claim 29 in the form 35. A shaped article of a sheet-like structure. as claimed in claim 31 in the form 36. A shaped article as claimed in claim 34 or claim 35 in the form of a film. 37. Moulded articles comprising polyesters according to any of claims 1 to 11, , 18, 20, 28 or 29. 38. Moulded articles comprising polyesters according to any of claims 12,17,19,21 or 30. 39· An anisotropic melt of a polyester as Claimed in any of claims 1 to 11, 13,15, 23 or 24. 40. An anisotropic melt of a polyester as claimed in any of claims 12,17,19,21 or 30. 41. A process for preparing a shaped article wherein said article is shaped from an anisotropic melt as claimed in claim 39. 50 ’t * · 42. A process for preparing a shaped article wherein said article is shaped from an anisotropic me Jt as claimed in claim 40. 43. A process as claimed in claim 4l in which said article 5 is a filament and is prepared by melt spinning from said anisotropic melt. 44. A process as claimed in claim 42 in which said article is a filament and is prepared by melt spinning from said anisotropic melt. 10 45. A process as claimed in claim 43 in which said melt spinning the filaments emerging from the spinning-means are subjected to spin-stretch factor of at least 10, whereby an oriented filament is produced. 46. A process as claimed in claim 44 in which in said 15 melt spinning the filaments emerging from the spinning-means are subjected to a spin-stretch factor of at least 10, whereby an oriented filament is produced. 47. Shaped articles whenever prepared by a process as claimed in claim 4l. 20 48. Shaped articles whenever prepared by a process as claimed in claim 42. 49. Filaments whenever prepared by a process as claimed in claim 43. 50. Filaments whenever prepared by a process as claimed 25 in claim 44. 51. Shaped articles which have a flow temperature of at least 200°C comprising polyesters as claimed in any of claims 1-31 substantially as herein described. 52. Shaped articles as claimed in claim 51 which are in the 3θ form of filaments.