CA1051148A - Copolyesters of derivatives of hydroquinone - Google Patents

Abstract

TITLE
PRODUCTS

ABSTRACT OF THE DISCLOSURE
This invention relates to a class of novel copolyesters derived from derivatives of hydroquinone and a mixture of ethylenedioxy-4,4'-dibenzoic acid with terephthalic, bibenzoic, hexahydroterephthalic acids ox 2,6-naphthalenedicarboxylic acid and to the fibers and other shaped articles prepared therefrom.
Also comprehended by this invention are the novel, optically anisotropic copolyester melts from which these shaped articles can be prepared.

Description

~35~
~0~
~ hile m~merous other polyesters have been pre-pared and evaluated, polyethylene terephthalat~ cont~nue~
to be the singularly preferred polyester in current com-mercial use. This species is used to prepare a ~ariety of products including films, textile filaments, tire cords, rope~, and other industxial and consumer products.
The deve~opment o~ new polyes1ters having one or more properties superior to polyethylene ~erephthalate has . 10 been a wor~hwhile object~ve.
SUM~RY OF THE INVENTION
This ~nvention provldes novel, anisotropic-melt-forming copolyesters of fiber-forming molecular wei~ht con-sisting essentially of units of the ~ormulas:

(I) -O-X-O-(II) -C ~ O-C~2C~2-0 ~ C- and ':
s ~ . (III) -C-~-C-.:' O O

where X is selected from the ~roup of chloro-, bromo-, methyl- and dlmethyl-l,lJ-phenylene radicals; up to ~0 mol %
o~ the formula I units may be replaced with O ~ O- units;
Y is selected from the group of 1,4-phenylene, 1,4-cyclo-hexylene, 4,4'~biphenylene~and 2,6~naphthylene radical~; and the mol ratlo of for.mula II ~o for~lula III units 1~ from 1:4 to ~ol. For~ula I units ~ld their replacement and th~
combined forr;lul~ I.l and III units are present ln substantially equimolar amount~.
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Al~o comprehended by this inventlon are optically anisotropic melts, novel shaped articles o~ the copolyesters and methods ~or preparing such shaped articles. Especially preferred are high strength fibers which are characterized by a desirable comblnation of properties including hydrolytic stability and in-rubber stabil~ty. These ~ibers are characterized by hlgh as-spun tenacity, orlentation and initial modulus ( ~ 200 gpd), and high modulus retention at eleva~ed temperatures, e.~.,,150C~ Certaln heat-treating processes enhance the properties of the ~iber~, DRAWING
The Fi~ure depicts light intensity traces obta~ned as described herein for two different polyesters in the æolid and melt states along with the background trace. One o~ the trace curves is of a polyester yielding an anisotropic melt while the other trace curve is of a polymer which yields an isotropic melt.
DESCRIPTION OF THE PREFERR~D EMBODIMENTS
~ ' The novel polyesters of this invention may be prepared ~rom appropriate dicarboxylic aclds and dihydric phenols or their deri~atives Useful Monomers ,..... - --- - - . :.
Dihydric phenols which may be used for preparing the copolyesters of this invention include 2-chlorohydro- ;
quinoneJ 2-bromohydroquinone, 2-methylhydroquinone and

2,6-dimethylhydroquinone. Phenolic reactants are used preferably in the derivative form such as the corresponding diacetates. Useful acids are terephthall~ acid3 2~6-naphthale~edicarboxylic acid, bibenzoic acid3 hexahydro terephthalic a~id,and ethylenedioxy-4,4'-dibenzoic acid.

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~a~5~8 The pre~erred copolyester-accordln~ to this inven-tion is poly(chloro-1,4-phenylene terephthalate/-ethylenedioxy-~,4'-dlbenzoate)(70/30 mol basis~. Other useful polyesters according to this invention include copoly(bromo-.,.
1,4-phenylene ethylenedioxy-4,4'-dibenzoate/terephthalate) (20/8Q), copoly~methyl~l,4-phenylene ethylenedioxy~4,4'-dibenzoate/hexahydroterephthala~e)(50/50), copoly~methyl-1,4-phen~lene ethylenedioxy~4,4'-diben%oate/4,4'-bibenæoate) (80/20)~ copoly(l,4-phenylene/bromo-1,4-phenylene 10 - ethylenedio}~y-4,LI'-dibenzoate~hexahydroterephthalate) (50/50 - 50/50), copoly(2~6-dim~thyl-1,4-phenylene ethylene~
dioxy-4~4'-dibenzoate/terephthalate~(70/30~ and copoly-(chloro-1,4-phenylene ethylenediox~y-4,4'-dibenzoate/2,6-naphthalate)(70/30).
The copolyesters of th~s invention have a moleculax weight sufficient for them to exhibit fiber-forming proper-ties. In the case of soluble polymers, inherent viscosities - of at least 0.5, measured as descrlbed hereinafter, are .~ u~e~ul ~or shaped articles ; 20 With polymers that are insoluble ln the solvent used for determining lnherent viscosity, the ~iber-forming potential may be demonstrated by melting a chip of poly~er in . . .
the anisotropic melt-forming temperature range on a heated bar (e.g.~ a modified Dennis bar, see Sorenson3 W. and Campbell, rT.W.
"Preparative Methods of Polymer Chemlstry", Interscience Publishers, Inc~, New York, 1961, p. 1~9_50), and slowly (~ 1 ~t/æec) withdrawing fibers from the melted pool.
' -P~
The novel polyesters o~ this invent~on may be prepared ~`rom appropriate monomers by melt polymer~zatlon . :.

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1C~S~L~41~il techniques, preferably under anhydrous conditlons in an inert ~tmosphere. For example3 equi~olar amounts o~ the reactant acids and the diacetate(s~ of the dihydric phenol(s) are combined in a reaction vessel equ~pped with a stirrer, nitrogen inlet tube~ and combined dist~llation head-condenser (to facilitate by-product remo~al). The reaction vessel and other equipment are dried and purged w1th nitrogen prior to use. The vessel and st$xred con-~ents~ maintained under nitrogen, are heated during which - 10 time the reactants polymeri~e and the by-product (acetic acid~ is removed via the distillation head~condenser and is collected. When the polymerization appears nearly com-~ plete, as indicated by the amount of acetic acid collected ; remaining constant, the molten polymer mass is placed under reduced pressure (e.g.~ 1 mm. Hg or less) and is heated, ; under nitrogen, at a higher temperature to facilitate removal of the remaining acetic acid and to completethe polymerizat~on. The mel~ may then be removed, cooled9 and allowed to solidify prior to purification and/or subsequent processing. Optionally5 ~he molten polymer may be transferred directly to an appropriate apparatus for preparation of shaped articles, e.g., a spinning unit for ~iber preparat$on.
~or smaller scale polyester synthese~, e.g., ~! .
in a polymer melt tube, stlrring actlon may be performed by a ~tream of $nert gas passing through the molten poly~
merization mixture. However, mechanical stirring is preferred.
.i -Polymerization conditions (e.g., temperature~
; 30 duration of heatingg pres~ure~) etcO) may be varied accord-: - 5 -. :.

~ 35~ 8 ing to, e.g., the reactants e~ployed and the degree o~
polymerizatlon desired.
Anisotropic Melts The anisotropy of these copolyesters in the molten state facilitates attainment of high orientation, strength9 high ini~ial modulus, and/or low shrlnl~age in as-spun fibers prepared from the melts~ and con~ributes to the capacity o~ these fibers to increase in tenacity on heat treatment in an essen~ially relaxed stat0. The melts are believed to comprise domains o~ pa~allel aligned polymer chains which in the spinning process produce as-spun oriented fibers.
Optical an~sotropy of the~copolyester melts can be determined by modification of known procedures.
It is ~ell known that translucent optically anisotropic materials cause light to be trans-mitted in optical systems equipped with crossed polarizers [seeJ e.g., S~ A. Jabarin and R. S. Stein, J. Phy~. Chem.g 77, 399 (1973)]~ whereas transmission of light is theoretically æero for isotropic materials. Thus~ optical anisotropy can be dete~mined by pl~cing a sample of the polymer on a heat-lng stage of a polarlzing microscope and bringing the tempera-ture up to and beyond the polymer flow temperature. If the polymer is optically anlsotropic in the melt, a bright field will be observed at temperatures above the polymer flow te~perature~ This may be confirmed through use of the thermo-optical ~est (TOT) des~rlbed below, The apparatus is slmilar to that described by I. Kirshenbaum, R.B. Isaacson, and W.~. Feist, Polymer Letters, 29 897~901 (1964~.
; 30 .. ~

~ - 6 -~(~S~4~3 Sh~ped Article Preparation The copolyesters of this invention are formed into useful shaped articles such as fibers, films, barR3 or other molded objectsJ etc. by~ e.g., presslng or by spinning, casting, or extruding the anisotropic melts .. .. .
thereof. Especially preferred are the highly oriented, strong fibers. ~or fiber preparation the molten polymer massS obtalned either direct~y from the melt polymerlza- ;
tion o~ the copolymer-.forming ingredients or vi.a the ; 10 melting of a plug or block of copolymer, is processed, e.g.~ thxough a melt spinning unit and extruded through a spinneret into a quenching atmosphere ~e.g., air ma~n-.,; .
; tained at room temperature) and wound up. As used herein~
the term "as-spun ~iber" refers to a fiber wh~ch has not been drawnJ stretched, or heat treated after e~truslon and .. ..
normal windu.p. In fact, the "as-spun" f~bers of the aniso- -tropic melts cannot be drawn in the usual sense, i.e., 100 or more.
~- Fibers may be prepared conveniently from single or multi-hole spinnerets. In the melt splnning cell, the temperatures to be maintained in the melt zone and at the spinneret will vary, of course, depending on the polymer ; being spun. Filterlng screens and discs may be employed in the spinneret pack. Alr or nitrogen may be used as a quench-., .
ing medium for the fibers leaving the spinneret. The as-spun flbers may be wound up at varying speedsJ e.g., from less than 100 yd/mln to 1,750 ~d~in or higher. Spin stretch fa~tor (SSFg defined hereinafter) vari~s with spinneret . , .
hole size and may range from 5 to 400. If desired~ a finish may be applied to the as-spun ~lbers.

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Fllms and stiff, tough bars may ~ prepared by con-ventional techniques. The relatlvely low viscosity o~ the melts ~-is of advantage in processing. Thus, a bar o~ copoly(chloro--l,4-phenylene ethylenedloxy-4,4~-dibenzoate/terephthalate)(70/30), (insoluble in sym-dichlorotetrafluoroacetone hydrate), in~ection molded at 290C, exhibits an average flexural modulus o~
1,450,000 lb/in2, flexural strength of 22,400 lb/in2 (ASTM-D 790 Method l, Proc. A) an~ notched Izod impact strength (ASTM-D-256, Method A) of ~.4 ~t-lb/inch o~ notch. A uniform, creasable ~ilm (thlckness = 8.27 mils) of the same compositlon pressed at 290C/5,50G lb/in2/15 sec. exhibits a modulus - 355 x 103 lb/in~, an elongation at break = 1.6~, and a breaking strength =
4.4 x 103 lb/in2 (Method of U.S. 3~6~7~579)o It is preferred that the polyesters have a ~low temperature within the range of 200C to 375 C. Polyesters with flow temperatures in excess of 375C are di~flcult to process (e.g., spin into useful fibers). Depending OIl structure, rapid decomposition o~ the polyesters may occur at higher ternperatures, i.e~, above 375C.
Plasticizers may be used to assist in the formation , . .
of shaped articles ~rom those polyesters which exhibit high melting point and/or high values of inherent viscosity.
Fiber~:~Pro~erties,_ eat Treatment, Utilit~
The as-spun fibers o* this invention are char-acterized by a tenacity within the range of ~rom at least 2 gpd and as high as about 9 gpd, an ~nitial modulus ~n excess of 200 gpd (and often exceeding 300 gpd)~ and an X-ray orientatlon angle of leSs ~han about 25.
The as-spun fibers of this invention may be - 30 sub~ected to heat treatment processes which .: . .; : : :

~05~ 8 provide fibers characterlzed by, e.g., higher levels of tenslle properties. For example, some heat treated fibers of this invention exhibit a tenacity o~ atl~ast about 10 grams per denier. These properties ~avor the use of these fibers of~hi~ invention in, eJg., belts of automobile tires, towing ropes, plastic reinforcement, knitted and woven fabricæ, and other app~ications wherein a combinat-lon of high strength, low extens~bi~i-ty~ low density, high inltial modulus, an~ low shrlnkage are required, e.g., ln the preparation of ropesg hawsers, and cordage for marine usage as noted in U.S. 3,~00,194.
In the heat treating process, fiber ~amples as skeins or on bobbins may be heated in an inert atmosphere (e.g., nitrogen) under a variety of conditions. Heating is normally conducted ~or ~rom 30 minutes ~o 4 h~urs at a tempera~ure approaching the fusion point but su~ficiently below to prevent substantial inter~ilament fusion, i.e., yarns are rew~ndable It is pre~erred that the maximum temperature be reached ~n a stepwise fashion When the fiber samples are wound on bobbins~ -it is preferred that a sof~, yielding surface be present on the bobbin, e.g.~ a covering o~ Fiberfrax3 (batted ceramic insulation of the Carborundum Company). The inert atmosphere with~l t~e oven or other heat-treating chamber ~s changed during the treating period by causing a flow o~
the inert gaæ (e.g., nitrogen)to enter and to leave the oven at a ra~e su~f~.c~.ent ~o remove by-products ~rom the vicinity of the ~iber.
MæASUREM¢

3~ X-~ra Orientatlon Angle: The orientation an~le ~0 A.
~~--g ~

~s~
values repor~ed l~ereln are obtalned by the procedure~
described in Kwolek U.S. 3~671J542J using Method Two of that patent. Sho~n parenthetically after each O.A. value in the examples is the position, 2~(degrees)9 o~ ~he speci~ic arc used to dete~ine the O.A. value. f Inherent Viscosity: Inherent YiScosity (ninh) is defined by the following equation:
ninh _ ~aherein (~rel) represents the relatlve viscosity and C
; 10 represents a concentration o~ 005 gram of the polymer in 100 ml o~ solvent, The relative viscosity ~nrel) is ; determined by dlv~ding the flow time in a capillary vis cometer of a dilute solution of the polymer by the flow time for the pure solvent. The dilute solutions used herein for determining (nrel) are of the concentratlon ex-" pressed by (C)J above; flow times are determlned at 30C;
the solven~ is sym~dichlorotetrafluoroacetone hydr~te.
~ LL~ L~9~ Filament and yarn properties are measured by the procedures shown in Morgan U.S. 3,827~998.
Tenacity~ T, and Modulus, Mi, are given in grams per denier.
Elongation~ E, is given in percent. At least three breaks ., , are averaged.
~t should be noted that di~f~rent values are obtained fro~ s~ngle ~ilamentæ (~ilament properties) and ; . ~ .
~om multi~ilament strands (yarn propertles) o~ the same ~am~le. Unless specified otherwiæe all properties given herein are filament properties.
tlcal Anlsotrop,y: Qptical anisotropy may be measured by the TOT method clescribed herein, S~in S _ tch Factor: The spin stretch factor ~ ' .'` . -' .
- ~0 - :
;. ~, ., : ' :

i~ de~ined as follo~Ys:
S.S~F. ~ Velocitv o~ yar~ at ~ind-u~ (ft/min) ~ -~ocit~ o~ ~el~ ~hrough ~pInrlelet ~I`t/mln) where ~el. of mel~ throu~h spinneret = Rate oP extrusion (cu ft/mln No. of sp~nnexet holes x ~ross-sectional area o~
on~ hole (sq ft) TOT AND FLOW TEMPE~ATURE APPARATUS AND ~THOD
The thermo-optical test (TOT~ requîres a polariz- ~-ing microscope which should have strain-free optics and sufficiently high extinction with c;rossed (~0~ polarl~ers .
to be capable of giving a background transmission speci-fied below. A Leitz Dialux Pol ~icroscope was used for the determinations reported herein. It was equipped with Polaroid polarizers, binocular eyepieces, and a heating stage. A photodetector (a photometer sensor) ~las attached at the top of the microscope barrel. The microscope had a 32X, long working distance objective, and a Red X plate (used only when making visual observations w~th crossed polarizers; ~`
inserted at an angle of 45 to each polarizer). White light from an incandescent light source is directed through the polarizerJ through the sample on the heating stage and through the analyzer to either the photodetector or the eyepieces. A
slide permits transferring the image from eyepieces to photo-detector. ~he heating stage used i5 one capable of being heated to 500C. A "Unitron" model MHS vacuum heating stage (Unitron Instrument Co., 66 ~eedham St., Ne~rton Highlands, Massachusetts 02161) was used. The photodetector signal is 3~ amplified by a photometer a~plifier and fed to the Y-~xis o~
an X-Y recorder. The system response to light intensity ., - '" ~.
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:
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~S1~41S~ i should be linear and the error of measurement within ~ 1 ~m.
on the chart paper. The heating stage is provided with two a~tached thermocouples~ One is connected to the X-axis of - the X-Y recorder to record stage temperature9 the other to a programmed temperature controller.
The microscope is focused ~isuaIly (with crossed polarizers) on a pol~ner sample prepared and mounted as described below. The sample, but not the cover slip(s), is removed from the optical path. The Polaroid analyz`er o~ the lQ micros~ope is removed from the optical pathg the slide 1~
~hifted to transfer the image to the photodetector and the i system i~ adjusked so that full~scale deflection (1~ cm on the chart paper used) on the ~axl.s o~ the X-~Y recorder corresponds to 36~ of the photometer signal. This is done by (l) ad~usting the light source intensity so that the photometer ; meter reads a value preselected so that it corresponds to a Y~axls reading on the recorder of 5 cm; (2) increasing the ., . . ~
amplification of the photometer by a factor o~ lO. This re-sults in the full scale recorder deflectlon of 18 cm corres--20 ponding to (18/50) X lOO or 36% of the photometer sigral. The ~;- background transmission value is recorded with crossed (90) polarizers and with the cover slip(s), but not the sample~ in the optical path, The background transmission in the system used should be independent of temperature and should be less than about 0.5 cm on the chart paper, ~ The sample is preferably a 5 ~m section microtomed ; with a di~mond knife ~rom a solid well-coalesced chip of pure polymer (e.g., as prepared in the exa~ples~ or by ~ melting and coalescing l~der nitrogen ~ome of the ground ':~30 polymer) mounted in epoxy resin. For materials that shatter , . . :': :
~ . :

~ 05'1~4f3 t~hen microtomed, duplicate ~ilms (about 5 ~m.~hick) of' polymer ~re prepared by heating a few particles of pure pol~mer between each of two sets of cover slips enclosed between a pair of microscope slides. By heating this ass~mbly quickly above the flow temperature (independently determined on a polymer particle~
, and applying pressure with a wooden tamp alternately over each `
,: sample, thin li~uid films of polymer are produced. These films .~ solidify when cooled. One solid film between cover slips is .. used ~or the TOT procedure; the other is used for a flow '.LO ~emperature measurement.
The sample section is pressed flat between cover slips.
One cover slip is removed and the sample on the remaining cover ,~ slip ls pla,ced (glass down) on the heating stage. The light .: intensity is set and the-background transmission is measured ' as described above. The sample (section~ or ~ilm between cover .. slips) then is positioned so that essentially all the iight inter-~: cepted by the photodetector will pass through the sample. With ~ .
' the sample between crosse~ (90) polarizers and. under nitrogen, .~ the light intensity and te~perature are recorded on the X-Y
.
o recorder as the temperature is raised at a programmed rate of . about 14C/min.from 25 to 450C. The sample temperature is , obtained ~rom the recorded temperature by use of' a suitable ;' calibra~ion curve.
The ;elo~ tempe~ ure oi~ copolymers or ~ibers is ob~erved ~rlsu~ r between crossed (90 ) pol&:ri~er3 on th~ ;
heat~g stagR assembly prev~ousl~r descxibed for the TOT pro~
cedure~ ~ib~r sample~ îor examirla~oll are prepared b~ cut~
the ~ber w~:th a xazox bl~de ~nd m~unt:l~g the samples on a co~rer lip. Fl0~1 temperature is that temperature at which the sharp 3 edges of a t~ny chip or particle o~ polymer or the cut ~iber edge .. .

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~ L~51~L~8 become xoundedO X:E the melt viscosity iG low enou~h, :l~low :L8 obsexYed, When a ~n ls used ~n ~he TOT procedure, a duplicate ~1~ is used ~ol~ the ~low temperature de~ermlnationO
Flow temperature ~s th~t temperature at which the ~ilm edges change con~our or the polymer ~lows~ Ob~exvations usually -are made at a heating .ra~e of 14~C/m~n. In a few cases, where xap:ld :~uxt}ler polymerization occurs~ a ~ster ra~e, about 50C/mln, is recommended.
It should be understood that the flow temperature ; 10 of these copolymers or fibers thereo~ may vary depending on their hlstory. For example, stepwise heating ordinarily raises the flow temperature. This perm~ts heat treatment at tempera~
tures above the initial ~low temperature but below the newly attained flow temperature level. The reported flow tempera-tu~ are those determined by these proceduxes.
Intensity Traces ~ .
The melt-~orming copolymers use~ul for ~ibers in this invention are considered to form anisotropic melts according to the thexmooptical test (TOT) if~ as a sample is heated between crossed (90) polarizers to temperatures above its flow temperature, the inte~sity of the light transmitted through the resulting anisotropic melt gives a træce whose height (1) is at least twice the height o~ the background transmission trace on the recorder chart and is at least 0.5 cm greater than the background transmission trace, or (2) increases to such values. Curve B of the Figure lllus-trates a type of lntensity trace usually obtained f`or systems :` forming anisotropic melts.
The ~n~enslty of l~ght txansmitted through ~he a~a~yzer ~hen isotropic ~elts (~he sample should be com~
pletely ~el~ed~ are placed be~leen crossed (90) polarizers ~s essenti~lly th~t of the backgrou~d transm~ssion (~ha-t ~:
~ 14 -~05~1~8 obtained when the sample but not the cover 61ip i~ outs~de the field of view with 90 crossed polarizers). As the melt forms, the intensity o~ the llght transmlssion (1) is essentially that of the background transmlssion or (2) decreases to such values from a ~igher value. Curve A of the Figure illustrates an intensity trace of a polymer form~
ing an isQtropic melt~

This example il.lu~trat~s preparation of copoly-(chloro-1,4-phenylene ethylenedioxy-494~-dibenzoate/
texepht~alate; 20/809 l~ole basis)J from which strong fibers are spunO
In a 250 ml round bottom flask equipped with a stirrer, distilling head, and argon bleed are combined chlorohydroguinone diacetate (13.7 g, o.o6 mole)~ tere-phthalic acid (8.o g, O. o48 mole), and ethylenedio~y-4,4'-: dibenzoic acid (3.6 g, 0.012 mole). These ingredients, under argon, are heated and stirred between 295-321C for 1 hr 35 min; the reaction mixture is solid at the end of this period. The reactlon temperature is then raised to , wlthin the range o~ 330-335C for about 1/2 hr, while the softened product is stirred; the by~product acetic acid is collected during these heating periods. The argon flow is halted and the reaction mixture heated within 332-335C
~or about 33 min under a reduced pressure of about 0.20 mm Hg. The product is collectedg ground in a Wiley mill, washed with acetone~ an~ dried in vacuo at 80C to yield 10.3 g of copolyme~. The copolymer i~ insoluble in the , , ~
inherenk viscosity test. The co~olymer ~lows at 325C and exhibits optical anlsotropy above that temperature (TOT).
~'he copvlymer is pa~sed through a spinnere~ pac~

.;
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1~511 ~48 and melt-spun throu~h a l-hole (0.023 cm d:Lam) spinneret, and wound up at ~peeds up to 5Q3 m/min to yield a filament with T/E/Mi/Den. = 3.6/1.1/392/19.0; O.A~ ~ 13 (18.0). For this spin~ the melt zone and spinneret temperatures are ln the range of 330 to 334C.
A yarn is prepared by plylng 8-10 filaments of ~he as-spun fiber. A skein of this yarn, under slight tension, is placed in an oven swept with a slowly flowing stream of hot nltrogen and is heated under these conditions: ~rom 30 to 280C over a 2 hr/18 mln period, then at 280C ~or 4 hrs.
The treated ~iber exhib~ts the *ollowing filament properties:
T/E/Mi/Den. - 10.1/3.3/381~25.

This example illustrates the preparation o~
copoly(chloro-134-phenylene ethylenedioxy-4,4'-dibenæoate/
terephthalate; 30/70, mole basis), and fibers thereof.
In an apparatus as described in Example 1 are combined chlorohydroqulnone d~acetate (95-97~ pure; con-tains dichlorohydroquinone diacetate isomers) (13~7 g, o.o6 mole)3 - ~o ethylenedioxy-4,4'-dibenzoic acid (5.4 g, 0.018 mole), and terephthallc acid (7~0 g, 0.042 mole). These reactants, under argonl are stirred and heated between 303-320C for : 66 min; the by-product acetic acid ie collected. After the argon ~low is halted, the reaction mixture is heated within 315-325C for 1 hr under a reduced pressure wlthln ; the range o~ 0.10-0.50 mm Hg. The copolymer is treated as in Example 1 to yield 13.7 g, of copolymer. The polymer is insoluble in the inherent viscosity test and has a flow temperature equal to ~99C, above which the copolymer ex-hibits optical anisotropy (T~T).
... .
~ The copolymer is spun as ln Example 1 (melt zone i'~ ' .
.

, ..

16~S~413 temperature = 292C~ spinneret temperature = 318"C) and wound up at 413 m/~:in to yield ~ .~ilament with T/E/Mi/Den. -7.T/2.5/1133/7 7; O.A. - 19 (18.8). A ~our-ply yarn i~
prepared and wound onto a Fiberfrax~ (batted ceramic insulat~on o~ the Carborundum Co~) - Covered perforated steel bobbin and is heated, under nitrogerl flowJ in an oven under these successive conditions: room temperature -155C/0>5 hr~ 155C-175C/l.0 hr, 175-220C/2.0 hr~ and 220-280C/2.0 hr~ the oven is allowed to cool to 150C
whereupon the bobbin is removedJ examined, and a samp~e (A) takenJ and the bobbin replaced in the oven and heated from 70-280C in one hr and at 280C for an additional hour (sample B). Sample (A) exhibits ~ilament T/E/Mi/ =
13/5.2/306~ Sample (B) exhiblts T ~ 18.
EY~l~P~E 3 This example illustrates the pxeparation of copoly(chloro-.~,4-phenylene ethylenedioxy-4, 4 ' ~dib en~oa t e/
~erephthalate; 50/~03 mole bas~s)0 F.~bers are prepa.red ~rom the melt o~ this copolymer~
In an app&ratu~ as described in E~ample 1 are combined chloroh~droquinone diacetate (13.7 g.. ~ o.o6 mol.e), ethylenedioxy-~,4'-dibenzoic acid (9~1 g., 0.03 mole)~
an~ tereph~halic acid (5~0 g., 0.03 mole). These reactants, under argon9 are stirred and hea~ed between 300-32QC. for 67 minutes; the by-product acetlc acid is collec~ed. The argon flow is halted and the reactlon m~x~ure is heated at 318C. for 1 hr. undex reduced pres-~ure within the range of 0.10-0.15 mm. ~g. The copolymer rcated as ln Exampl~ 1 ~dryin~, temperature is 60C) to yield 16.9 g of copolymer that is insoluble in the inherent 3 viscosity test~ The copolymer f~ows a~ 243C and exhibits .
. . .

s~
op~lcal ani~otropy above that temperature (TOT).
The copol~mer is spun as in Example 1 (mel~ zone ~emperature = 238C,~ splnnAeret tempe~ature = 277C.) and wound up at 700 ~/min. to Yi$ld ~ filament with T/E/Mi~
Den. = 4.1/1.3/~14~4.3; O.A. - 22 (18.9). Four ~lla-ments are plied to give a yarn of about 17 denlex. The yarn is heated as in ~xa~ple 2 under these cond~tions:
room temper~tuIe ~ 150C./0.5 hr.~ 150-170C./l.O hr., 170-^220C./2.0 hr., and 220-230~C./4.0 hr. The t~eated ~arn exhibits filamen~ T/E/~ ben. = 6 ~ 2/201/387/3~ 3~

Th~s example illustrates the preparation of ~opol~chloro^l,~^phenylene eth~lenedioxy-4,4~-dibenzoate/
; ~,erephthalate; 70/30~ mol~ basis), ~ibers are prepared ~rom ~ anisotro~ic melt o~ this co~olvmerA
n an apparatus as described in Example 1 are combined ~hlorohydroquinone diacetate (13.7 g., o.o6 mole~, e~hylenedioxyr~J~'^dibenzoic acid (12~7 g,5 0~042 mole)~
and ~ereph~hal~c acid (3.0 g., 0.018 mole). These rea~tan~s~
- 20 under ar~on~ are s~lrred and h0ated between 310-320C.
~r 70 minO; ~he py-produ~t acetic acid is collec~ed.
~he argon f~ow is halted and the reaction mixture ~s heated between ~18-320oc~ ~or 1 hr. under reduGed pressure wi~hin ~he ran~e o~ 0.10-0~3~ mm. Hg. The copolymer is ~reated as in ~xample ~ to yield 19.2 g. of copolymer~
nlnh - 1.2, flow temperature = 256~C., above which the -~op~lymer exhibits opt~cal anisotropy (TOT).
The c~polymer îs spun as in ~xample 1 (melt zone ~emperature - ?560e~ sp~nneret temperature = 312C.
an~ woun~ up ~t 735 m,~m~n, ~o yield ~ ~ilament with ' . :' 5119s8 T/E/:~i/Den. = 4.6/l.~/373/4.l~; O~Ar = 21 (19~1 )~
Four rilaments are plied to give a yarn of about 17 den~er. After the yarn is heated as ~n Example 3~the ~iber T/E/Mi/Den. = 5~ 2/1~ 8/368/4~ 3~

EXA~PLE 5 This example illustrates the preparation of copoly~chloro-lJ4-phenyler~e ethylenedioxy-4,4t-dibenzoate/ ,: .

4,4'-biben~oate; 50/50, mole basis), plus an anlsotropic melt and ~ibers thereof.
In an apparatus as described in Example 1 are ` ~ ' combined chlorohydroquinone diacetate (13~7 g., o.o6 mole), e~hylenedioxy~4,4t-dibenzoic acid ~9.1 g.-, 0.03 mole)3 and 4~4~-bibenzoic; acid (7.3 g.; 0.03 mole). These reactantsg under argon~ are stirred ænd heated between 305-343C.
for about 65 min.; the by product acetic acid is ~ollected.
.~, . . :
The argon flow is halted and the reaction mixture is heated at 342C. ~or 1 hr. under reduced pressure within the range of 0.2-1.5 mm Hg. The copolymer is treated as in Example 1 to yield 14~,9 g o~ copolymer insoluble in the inhexent viscosity test. The copolymer flow tempera-ture is 253C~ above which the copolymer exhibits optical anisotropy (TOT ) .
The copolymer ls spun as ln Example 1 ~melt '! and spinneret temperature - 266C) and wound up at 137 i m/min to yield a filament with T/EfMi/ben. ~ 4.4`/2.1/
321/16.4; O.A. = 24 (18.8). Four ~ilaments are plied to give a yarn of about 65 denier. After the yarn is heated as in Example 3, it exhibits T/E/~ifDen. =
4.9/2.3/231/53 (some filament ~us ion 3 .
EXAMPLE ~
This example illustrateæ the preparation of ' .

', S~ 8 copoly(l~4-pnerlylene/cnloro-1,4-phenylene ethylenedio,yy~4,4'-dibenzoate/terephthalate; 50/50-50/50, : mole basis). This copolymer ~orms an anisotropic melt and strong fibers.
In an apparatus as described in ~Yample 1 are comblned hydroquinone diace~a~e (5.8 g., 0.03 mole)~
chlorohydroquinone diace~ate (6.8 g., 0.03 mole), - ethylenediox~-4,~l-dibenz~ic acid (9.1 g.9 0.03 mole), and terephthalic ~cid (5.0 g., 0.03 mole). These reactants~ under argon3 are stirred and heated between 309-324C. for 70 min.; the by-product ace.~lc acid is collected. A~er the argon ~low is halted, the react~on mi~ture is hea~ed ~ithin 318-324C. ~or 1 hr~ under a " reduced pressure of about 0.10 mm. ~g. The product i5 treated as in Example 3 to yield 15.2 g o~ copolymer that ls insoluble ln the inherent viscoslty tes-t, The .:
copolymer flows at 286C and exhibits optical anisotropy above that temperature (TOT), Th~ copolymer is spun as in Example 1 (melt . :
20 ~one ~empera~ure = 308C.~ spinneret tempera~ure = 340C.) and wound up a~ 579 m./m~n~ to yield a ~ilamen~ wi~h T~E/Mi/ben. - 5.5/2.2/357/4.8; 00~. - 15 (19~5). A `
four-ply yarn is prepared and hea~ ~rea~ed as in Example 2 ~ -(sample B) to yield a product with filament T/E/Mi/ben. = :
11.0/3. 7hg8/5. 3.

-~,~ 7 ~his example i~lustrates ~he preparation o~
: copoly(chloro-1,4-phenylene ethylenedioxy-494'-dibenzoate/ :;
hexahydroterephthala~e; 50/50, mole basis), and fibers thereof.
3 Xn an apparatus as described in :E:xample ~ are ' '' .~ ' :.

~ S~ 4 comb~ned chlorohy~roquinone diaceta-te tl3~7 g.g 0. o6 mole), e~hylenedio.yy-4,~'-dibenzoic acid (9.1 6.. -3 mole~ and hexahydroterephthalic acid (100~ tra~s-isomer,

5.2 g., 0.03 mole). These reactants, under ar~on) are stirred and heated bet~een 310-335C. fox 68 min:; the by-product acetic acid is collected. The argon ~low is : halted and the reaction mixture is heated at 322C. ~or ~ 64 min. under reduced pressure (< 1 mm. Hg). The copolymer . is kreated as in Example 3 (washed 2X with ace-tone) to yield 16.8 ~. o~ copolymer~ ~inh = 1.63. The copolymer ~lows at 213C. and exhibi~s optical anisotropy above .~hat temperatuxe (TOT)o The copolymer is spun as in Example 1 (melt zone .; temperature = 260Cr~ spinneret ~emperature = 285C.) and wound up at 238 m./min. to yield a filament with T/E/Mi~
Den. = 3.7/2~2/240/1~.4; O.A. = 24 (18.7). Filaments are plied and the yarn hea~ed as in Example 1 under these .- condition~: from 25-198C. over a 33 min. period, ~hen at 200C. for 4 hrs. ~or this fiber, filamen~ T/E~ Den. =
4.5/2.7/238/12.
, , .
. . .
.,, , ' , , ;

, .. . .
''''' . . .

~ 21 -

Claims (11)

WHAT IS CLAIMED IS:

1. A fiber-forming melt spinnable copolyester capable of forming an anisotropic melt and consisting essentially of units of the formula:

(I) -O-X-O-(II) and (III) wherein X represents a member selected from the group consisting of chloro-, bromo-, methyl- and dimethyl-1,4-phenylene radicals; up to 80 mol % of formula I units may be replaced with units; Y is selected from the group of 1,4-phenylene, 1,4-cyclohexylene, 4,4'-biphenylene, and 2,6-naphthylene radicals; and the mol ratio of formula II to formula III units is from 1:4 to 4:1.

2. Poly(chloro-1,4-phenylene ethylenedioxy-4,4'-dibenzoate/terephthalate)(30/70) according to claim 1.

3. An anisotropic melt of the copolyester of Claim 1.

4. A shaped article of the copolyester of Claim 1.

5. A fiber of the copolyester of Claim 1.

6. An as-spun fiber of the copolyester of Claim 1 having a tenacity of at least 2 gpd, an initial modulus in excess of 200 gpd and an X-ray orientation angle of less than about 25°.

7. Copoly(chloro-1,4-phenylene ethylenedioxy-4,4'-dibenzoate/4,4'-bibenzoate)(50/50) according to Claim 1.

8. Copoly(1,4-phenylene/chloro-1,4-phenylene ethylenedioxy-4,4'-dibenzoate/terephthalate)(50/50-50/50) according to Claim 1.

9. Copoly(chloro-1,4-phenylene ethylenedioxy-4,4'-dibenzoate/hexahydroterephthalate)(50/50) according to Claim 1.

10. A film of the copolyester of Claim 1.

11. The polymer of Claim 1 wherein X is chloro-1,4-phenylene and Y is 1,4-phenylene.