CA1082399A - Melt polymerization process and linear aromatic polyester prepared therein - Google Patents

Abstract

MELT POLYMERIZATION PROCESS AND LINEAR
AROMATIC POLYESTERS PREPARED THEREIN

ABSTRACT OF THE DISCLOSURE
Linear aromatic polyesters are produced by the melt polymerization process by mixing a bisphenol, a diaryl ester of a dicarboxylic acid and an oligomeric polyester comprised of an aliphatic glycol and a dicarboxylic acid and reacting the mixture in the presence of a transesterification catalyst.

Description

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BACKGROUND OF T~IE INVENTION
Polyesters made from aromatic dicarboxylic acids and diphenolic com-pounds are particularly well known for the;r su;tab;lity for molding, ex-trusion and solvent casting applications. Among the many methods known for preparing such polyesters, the react;on of the dihal;de of the d;carboxyl;c acid w;th the diphenol ;n the presence of an ac;d binding med;um in the well known ";nterfacial" and solution methods are the most common. The react;on between a d;alky1 ester of the dicarboxylic acid and a diphenolic compound is slow and requires long heating times because of the lack of reactivity of phenolic hydroxyls in general toward the dialkyl ester, more- ~
~j over, polyesters formed in this manner are usually of low molecular weight ~ -and because of the long heating periods necessary, have a tendency to be badly degraded and discolored. It is further known that the slowness of the reaction and long heating times can be eliminated by using a diaryl . .
ester instead of the dialkyl ester of the dicarboxylic acid. See, e.g., British patent 924,607.
The polyaryl esters produced by the transesterification and polycon-densation of the diaryl esters of aromatic dicarboxylic acids and dihydric ;, : -phenols have such high melting viscosities that the degree of polycondensa~
~ 20 tion required for obtaining good mechanical properties cannot be reached : in conventional stirred tank reactors. For the purpose of eliminating this disadvantage, it has been proposed heretofore to replace a part of the dihydric phenols with equiva1ent amounts oP glycols. In U. S. 3,339,170 : -Blaschke et al. prepared polymers from a diaryl ester, a bisphenol and a glycol. However,-this process has the disadvantages of poor reducibility ` --. . ., ~
and the necessi-ty that the reactants be present in an exactly stoichiometric proportion with respect to each other.
.
The use of a "prepolymer" in preparing l;near aromatic polyesters is -~~ not new. For example, Shatz et al, (U. S. 3,498,950) teach reacting a di- -functional aliphatic modifier such as glycol with an excess of diacid halide ~- followed by reacting the resulting "prepolymer" with a bisphenol. Schade ~, '

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iLO ~3~3 g~3 et al. in U. S. pakents 3,299,172 and 3,413,37~, teach reacting diaryl esters of the aromatic dicarboxylic acids with dihydric phenols until the polyester produced has a melting viscosity aboYe about 2000 poise and then adding a linear thermoplastic polyester consisting of terephthallc acid units, isophthalic acid units or mixtures thereof as well as residues of di-primary di-alcohols and then continuing the polycondensation until the product has a specific viscosity of about 0.7 or more. Schade et al.
- observed that if the di-alcohol polyester is added to the reaction mixture ~`~ 10 at the beginning or even after the completion of the transesterification, mixed polyesters are obtained which are relatively brittle despite a high ~` degree of polycondensation, and do not display any advantageous properties apart from their softening point.
In contrast to Schade et al., we have discovered that linear aromatic -' 15 polyesters having appropriate properties for molding, extruding and solvent : '1 casting applications can be obtained by transesterification and polyconden-sation of mixtures of diaryl esters of dicarboxylic acids, dihydric phenols and an oligomer of a dicarboxylic acid and a diol. High impact polyesters , can be produced by the process of this invention. ;
20 - Accordingly, it is the object of this invention to provide a newlmethod - for producing linear aromatic polyesters suitable For molding, extrusion and ~-~ solvent cast;ng applicat;ons and they thereby provide a new and useful linear ` aromat;c polyesters. These and other objects of the invention will become , apparent to those skilled in the art from the following detailed description.
~-l 25 SUMMARY OF THE INVENTION .
This invention relates to linear aromatic polyesters and the method by ~1hich they are prepared. More particularly, the invention relates to linear aromatic polyesters which are prepared by the melt transesterification ,, and polycondensation o~ a bisphenol, a diaryl ester of dicarboxylic acid ~`
~ 30 -and an oligomer of a dicarboxylic acid~and d diol.
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DESCRIPlION OF THE PREFERRED EMBODIMENTS
In accordance with the present inventlon, l;near aromatic polyesters are prepared by first mixing a bisphenol, a diaryl ester of dicarboxylic acid and an oligomer of a dicarboxylic acid and a diol, and then reacting S the resulting mixture in the presence of a transesterification catalyst.
The bisphenols which can be used in the process of this invention ~;, correspond to the general formula:
HO - Ar - (E)x ~ Ar - OH
,: ' ' ' . ~ 10 Tb Gm T'b wherein Ar is aromatic, preferably con-taining 6-18 carbon atoms (including phenyl, biphenyl and napthyl); G is alkyl, haloalkyl, aryl, haloaryl, alkylaryl, haloalkylaryl, arylalkyl, haloarylalkyl, cycloalkyl, and halo-cycloalkyl; E is a divalent (or di-substituted) alkylene, haloalkylene, cycloalkylene, halocycloalkylene, arylene, or haloarylenei -O-, -S-~ -SO-, -S02-, -S03-, -CO-, GP~ or GN ~; T and T' are independently selected from the group of halogen, such as chlorine or bromine, G or OG; m is an integer from O to the number of replaceable hydrogen atoms on E; b is an integer from . , .
- O to the number of replaceable hydrogen atoms on Ar, and x is O or 1. When there is a plurality of G substituents in the bisphenols, such substituents -, : .
may be the same or different. The T and T' substituents may occur in the ortho, meta or para-positions with respect to the hydroxyl radical. The foregoing hydrocarbon radicals preferably have carbon atoms as follows:
alkyl, haloalkyl, alkylene and haloalkylene of 1 to 14 carbons, aryl, haloaryl, arylene and haloarylene of 6 to 14 carbons; alkylaryl, haloalkylaryl, arylalkyl and haloarylalkyl of 7 to 14 carbons; and cycloalkyl, halocyclo- ~;~
~' alkyl, cycloalkylene and halocycloalkylene of 4 to 14 carbons. Additionally, mixtures of the above described bisphenols rnay be ernployed to obtain a polymer with especiaily desired properties. The bisphenols generally contain 12 to about 30 carbon atoms and preferably 12 to about 25 carbon atoms.
Typical examples of bisphenols having the foregoing formula include .`-.' ; :

'", ' . ~, .. ,, , , , :, , ;. ~ : - , .. . .
-~ ~ - . ,. , , - ., --.

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b;s(4-hydroxyphenyl)methane. bis(2-hydroxyphenyl)methane, 4-hydroxyphenyl, ~.
2-hydroxyphenyl methane and mixtures thereof; bis(3-methyl-4-hydroxyphenyl)- -methane, bis(~-hydroxy-3,5-dichlorophenyl)methane, bis(4-hydroxy-3,5-dibro-mophenyl)methane, bis(4-hyd~oxy-3,5-difluorophenyl)methane, bisphenol-A[bis-(4-hydroxyphenyl)-2,2-propane~, bis(3-chloro-4-hydroxyphenyl)-2,2-propane, bis(4-hydroxy-3,5-dichlorophenyl)-2,2-propane, bis(4-hydroxynaphthyl)-2,2-.; propane, bis(4-hydroxyphenyl)phenyl methane, b;s(4-hydroxyphenyl)diph~nyl methane, bis(4-hydroxyphenyl)-4'-methyl phenyl methane, bis~4-hydroxyphenyl)-4'-chlorophenyl methane, bis(4-hydroxyphenyl)2,2,2-trichloro-1,1,2-ethane, bis(4-hydroxyphenyl)-1,1-cyclohexane, bis(4-hydroxyphenyl)cyclohexyl methane, . 4,4-dihydroxyphenyl, 2,2'-dihydroxydiphenyl, dihydroxyhaphthylenes, bis(4-; hydroxyphenyl)-2,2-butane, bis(2,6-dichloro-4-hydroxyphenyl)-2,2-propane, bîs(2-`
methyl-4-hydroxyphenyl)-2,2-propane, bis(3-methyl-4-hydroxyphenyl)-l,l-' cyclohexane, bis(2-hydroxy-4-methylphenyl)-1,1-butane, bis(2-hydroxy-~-ter-15 butylphenyl)-2,2-propane, bis(4-hydroxyphenyl)-1-phenyl-l,l-ethane, 4,4'-dihydroxy-3 methyl diphenyl-2,2-propane, 4,4'-dihydroxy-3-methyl-3'-isopropyl diph~nyl-2,2-butane, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone, . bis(4-hydroxyphenyl)oxide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl) sulfoxide, bis(4-hydroxyphenyl)sulfonate, bis (4-hydroxyphenyl)amine, bis(4-hydroxypheny1)phenyl phosphine oxide. 2,2-bis(3-chloro 4-hydroxyphenyl)-propane; 4,4'-(cyclohexymethylene) bis(2,6-dichlorophenol), 2,2 bis-(3,5-dichloro-4-hydroxyphenyl)-propane, 2,2-bis-3,5-dibromo-4-hydroxyphenyl)-~ propane, l,l-bis-(3,5-dichloro-4-hydroxyphenyl)-1-phenylethane, 2,2-bis-(3,5-i:, dibromo-4-hydroxyphenyl)-hexane, 4,4'-dihydroxy-3,3', 5,5'-tetra-chlorodi-l 25 phenyl, 2,2-bis-(3-chloro-4-hydroxyphenyl)-propane, 2,2-bis-(3,5-dibromo-4-:! hydroxyphenyl)-propane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane, tetra- .
chlorodiphenylolsulfone, bis(3,5-dibromo-4-hydroxyphenyl)-phenyl phosphine oxide, bis(3,5-dibromo-4-hydroxyphenyl)-sul,oxide, bis(3,5-dibromo-4-hydroxy- : :~
phenyl)-sulfone, bis(3,5-dibromo-4-hydroxyphenyl)-sulfonate, bis(3,5-dibromo-4-hydroxyphenyl)-sulfide, bis(3,5-dibromo-4-hydroxyphenyl)-amine, bis(3,5-dibromo-4-hydroxyphenyl)-ketone, and 2,3,5,6,2',3',5',6',-octochloro-4,4'-hydroxy biphenyl. Representative biphenols are o,o-biphenol, m,m'biphenoli .

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p,p'-biphenol; bicresols, such as 4,4'-bi-o-cresol, 6,6-bi-o-cresol, 4,4'-bi-m-cresol; dibenzyl biphenols such as a,a'-d;phenol-4,4'-bi-o-cresol;
diethyl biphenols such as 2,2'-diethyl-p,p;-biphenol, and 5,5'-diethyl-o, o'-biphenol; dipropyl biphenols such as 5,5'-dipropyl-o,o'-biphenol and 2,2'-diisopropy1-p,p'-biphenol; diallyl biphenols such as 2,2'-diallyl-p,p'-biphenol; and dihalobiphenols, such as 4,4'-dibromo-o,o'-biphenol.
~lixtures of isomers of the foregoing bisphenols can be used.
~` The diaryl esters of dicarboxylic acids which are employed in this ~ invention correspond to the formula:
`: 10 o o ~ ~ " ~ .
RX-C- ( Z)n-C-XR , .
. ~ .
~` in which R and R' are the same or different aryl groups; X is oxygen or sulfur, Z is alkylene, -Ar- or -Ar-Y-Ar- where Ar has the same definition as given ~1 with respect to the bispheno1s, Y is alkylene~ of 1 to 10 carbons, haloalkyl-ene, -0-, -S-, -S0-, -S02-, -S03-, -C0-, GP ~ 0 or GN~ and n is 0 or 1.
atoms.
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Suitable dicarboxylic acids from which the diaryl esters are derived (i.e., where R and R' are hydrogen) include aromatic dicarboxyli~ acids `~'! such as phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, bis(4-carboxy)-diphenyl, bis(4-carboxyphenyl)-ether, bis(4-carboxyphenyl)-sulfone, bis(4-carboxyphenyl)-carbonyl, bis(4-carboxyphenyl~-methane, bis(4-carboxyphenyl)-dichloromethane, 1,2- and 1,1-bis(4-carboxyphenyl)-ethane, 1,2- and 2,2-bis(4-carboxyphenyl)-propane, 1,2- and 2,2-bls(3-carboxyphenyl)-propane, 2,2-bis(4-carboxyphenyl)-1,1-dimethyl propane, 1,1- and 2,2-bis(4-carboxyphenyl)-butane, 1,1- and 2,2-bis(4-carboxyphenyl)-pentane, 3,3-bis-(4-carboxyphenyl)-heptane, 3,3-bis(3-carboxyphenyl)-heptane, and aliphatic acids such as oxalic acid, adipic acid, succinic acid, malonic acid, sebacic acid, glutaric acid, azela;c, suberic acid and the like. Isophthalic acid and terephthalic acid are preferred because of their availability and low cost . ' ` ~

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The preferred aryl ester is the phenyl ester but other aryl esters, e.g., the cresyl esters can also be used but they are usually more expensive to prepare. In general, the aryl moieties R and R' will contain 6 to 10 carbon atoms. Included in the aryl esters are those derived from alkylphenols, such as cresol, xylene a~d the like;
the halophenols such as parachlorophenol, 3,5-dichlorophenol, 3,5-di-bromophenol, and the likei nitrophenols such as para-nitrophenol and the like. The aryl esters can be derived from the corresponding thio-phenols. Mixtures of the foregoing diaryl esters can be employed.
` 10 The oligomer employed in this invention is the transesterification and polycondensation product of a dialkyl ester of dicarboxylic acid and a dihydric alcohol. The dialkyl esters are of the same ~ormula : - ~
~` as the foregoing diaryl esters except, of course, the R and R' groups are alkyl instead of aryl. The alkyl groups are preferably alkyl of 1 to 10 carbon atoms such as methyl, ethyls propyl, heptyl, octyl , ~; and nonyl. The dicarboxylic acids are those disclosed hereinbefore.
The dihydric alcohols employed in preparing the oligomer can contain 2 to about 100 carbon atoms, and preferably ~ to about 20 `~ carbon atoms. Typical examples include ethylene glycol, diethylene` 20 glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, hexylene glycol, 2-methyl-2-ethyl-1,3-propanediol,2-ethyl-1,3-hexane-;~ diol, 1,5-pentanediol, thiodiglycol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,3-butylene glycol, neopentyl glycol, ~; 25 1,2-dimethyl-1,2-cyclopentanediol, 1,2-cylcohexanediol, 1,2-dimethyl-; 1,2-hexanediol, polyalkylene ether glycols and polyester glycols such as polydecamethylene sebacate, and aryi alkylene glycols such ~ - 7 -: ~
,' .
E~` ' ~ ' .

as oxyalkylated bisphenol-A, and mixture thereoF. Minor proportions of monohydric and po1yhydric alcohols can be employed to control molecular weight.
The oligomer can be prepared in accordance with processes known in the art, e.g., by mixing and heating the aliphatic diol with the dialkyl ester of a dicarboxylic acid in the presence of a transesteri- ;
fication catalyst. Since the reaction is stoichiometric and there-fore stoichiometric proportions .,~

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3~g of the dialkyl ester and diol can be employed, we prefer to use an excess of diol in preparing the oligomer because the diol ;s generally the more volatile of the two components. We also prefer to conduct the reaction under nitrogen or a vacuum up to about 0.1 millimeter of mercury.
In preparlng the linear aromatic polyesters of the present invention, the three components are subjected to the melt polycondensation and trans-esterification procedure which is well known in the art. That is, the diaryl ester, bisphenol and oli~omer are placed in an appropriate reaction vessel, such as a stirred tank reactor or agitated thin film reactor, with the appropriate catalyst and, if defs;red, stabilizing agents and heated to reaction temperature which is generally about 150C to 380C and preferably about 190 to 330. The linear aromatic polyester thus produced is there-; after recovered. The diaryl ester of an aromatic carboxy1ic acSd and the hydroxyl component (bisphenol and oligomer) are employed in stoichiometric .~
l 15 proportions although either component can be present in an excess af up :, :
~ to about 120% but preferably about 5%. Within the hydroxyl component, ~he , . . .
` ratio of the bisphenol to glycol can vary from 95:15 to 15:8~ff but is pre-ferably about 1 The transesterification and polycondensat10n catalysts employed in the present invention are well known to those skilled in the art and any of the known catalysts can be employed. Examples of such catalysts include alkali metal and alkaline earth metal phenylates, magnesium oxide, lead oxide, zinc oxide, antimony trioxide, alkali metal alkoxides, titanates, metallic hydrides and borohydrides such as lithiun1 hydride and potassium borohydride, alkali metal hydroxides and alcoholates. At the present time, we prefer to use lithium hydride or lithium phenoxide as the catalyst.
- Illustrative stabilizers include, but are not limited to, aryl phosphites, ,.i ~ .
alkyl phosphites, and mixed alkyl aryl phosphites.
-I The properties oligomers and polyesters of this invention are im-proved by excluding oxygen from the reaction vessels, therefore, an inert . ~ .
~ -~' gas or vacuum is employed to exclude oxygen. Nitrogen is the most convenient although other inert gases, such as argon, helium and neon, or mixtures of inert gases can be used. Also vacuum, from about 0.1 to 30 inches of mercury, is advantageous to aid in the removal of by-products.
The type of product produced by the processes o-f the invention is dependent on the degree of polymerization (d.p.) of the oligomer. Generally, the use of linear molecular weight oligomers with a lower degree of poly-merization, for example of 1 or 2 up to about 8, results in polymers having high impact strength, lower melt viscasity and which are suitable for injection molding and extrusion processes~ The use of the oligomers which haYe a higher degree of polymerization, such as 8 or above, result in novel polymers having unique skructures and which have higher heat distortion temperatures, higher melt v;scosities and improved chemical ` resistance. These polymers are better suited to extrusion as a method of shaping the polymer. Considerable influence on the properties of the polymers produced by the processes of the invention is exerted by the -glycol employed. Thus, the use of a more rigid diol such as ethylene -glycol results in the production of a polymer having a higher melt viscosity .
for the same degree of polymerization as neopentyl glycol. The polymeric diols such as the polyether glycols and polyester glycols result in the production of elastomer type products when the degree o~f polymerization is at a level of 8 or more. Thus the processes of the invention have expanded ;~ the horizons of the types of products obtainable with the aromatic polyesters of the bisphenol type.
The following examples are set forth in order to further illustrate the invention. Throughout this specification and claims, all temperatures . are in degrees Centigrade and all parts and percentages are by weight unless otherllise specified.

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~L08Z399 Exanlpl e I
Preparation of Hydroxyl End Capped Ol-igomer 359.1 9 (3.55 mols) of neopentyl ylycol tdried at 70C for 16 hours in a vacuum oven), 326 g (1.68 mols) of dimethyl terephthalate and (0.16 g tetrabutyl titanate) were charged into a l-liter, 3-necked~ round bottom flask equipped w;th a nitrogen inlet, mechanical stirrer, and a 6" Vigreux column with a head, condenser and graduated collector (for the by-product methanol). The catalyst employed was tetrabutyl titanate in an amount o~
0.16 9 (0.05% based on the weight of the dimethyl terephthalate).
~ A slow nitrogen flow was begun and the reaction vessel was heated with - stirring at about 200C for 6 hours. Approximately 96% o~ the theoretical methanol was collected. The Vigreux column was then removed, the head was put directly on the flask and an adapter connected it to a 3-necked Flask with a stopper in the middle and an outlet for a vacuum pump. The reaction ~as continued at about 200C and vacuum was applied. After 1.3 hours, the vacuum was 1 mm of mercury and 162 g oF the neopentyl glycol was in the trap.
~i The reaction mixture was then poured into a glass pan and allowed to cool to room temperature.
2Q The resulting product was a clear, water-white, br;ttle solid which could be ground up. The hydroxyl number determined in pyridine and acetic anhydride was determined to be 66.3 mg KOH/g and the molecular weight of the oligomer, calculated from this hydroxyl number "~las 1692.
Example 2 , . .
23 Preparation oF Linear Aromatic Po~esters Into an oil-jacke-ted reactor equipped with a stirrer, nitrogen inlet, and a trap with an outlet for establishing a vacuum "~ere charged the following reactants * trade mark ~; .
1~

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20.62 9 (0.0904 mol) bisphenol-A
20.0 9 (O.oll9 mol) oligomer oF Example 1 32.56 9 (0.1025 mol) diphenyl terephthalate The system was flushed with nitrogen and 2 drops (about 26 mg) of tetrabutyl titanate ~las added to the reactor.
The reaction mixture was heated to 260C over about a 15-minute period with stirring and upon reaching that temperature, evacuat;on of the system ~as begun. The phenol came out rapidly under the vacuum and the reaction mixture was orange and clear and low viscosity. The maximum vacuum 10 was reached (0.05-0.25 mm) after 1 hour. After a total time at 260~ of .. . .
about 4 hours, the temperature was raised to 290C while maintainin~ maximum vacuum. After 1 hour at the higher temperature, the polymer ~as removed and cooled to room temperature.
- The resulting polymer ~Jas clear, tough and had an intrinsic viscosity ~- 15 of 0.805, in CHC12CHC12 at 25C, and a Tg measured in the Perkin Elmer DCS-2 at 10C per nlinute was 126-135C. -The linear aroma~ic polymer thus produced was molded at 300C in a ., *
- Minimax Molder and then tested in a high speed tensile impact tester (both instruments produced by Custom Scientific Instruments, Inc.). Values of ~, *
20 about 8 inch/pounds were obtained as compared to 2.3 for Lustrex HF-77 .. . .
polystyrene (which has 0.3 foot/pound notched Izod impact strength), 4.3 *
for Blendex 101 ABS (which has 8 foot/pounds no~ched Izod impact strength) ~
and approximately 10.2 ~or polycarbonate, (which has 16 foot/pounds notched ~ -Izod impact strength). These test results demonstrate tha-t the linear 2 aromatic polyester produced is a high impact polymer.
Examples 3-4 Examples 1 and 2 ~lere repeated using zinc acetate .2H~0 and antimony oxide, respectively, as the catalyst in place of the tetrabutyl titanate.
The resultin3 linear aromatic polyesters had a pale yellow color.
~o Ex~ples 5-6 Following the procedure of Example 1, a~hydroxyl end capped oligomer was prepared from dimethyl terephthalate and polyethylene glycol. The * trade mark ,, .. ,. I . .

procedure of Example 2 was then repeated employing this oligomer in place of the neopentyl glycol-dimethyl terephthalate oligomer to produce a thermoplastic l;near aromat;c polyester having rubbery character;st;cs, good dimensional stability at elevated temperatures, good oxidatlve stability and chemical and solvent resistance.
Example 7 A.) An oligomer was prepared by reacting 6.35 mols of neopentyl glycol with 3.01 moles dimethyl terephthalate and 0.29 gm zinc acetate .2H20 under a slow flow of nitrogen at 168 to 199C over about 4 hours during which time 221 mols of methanol were removed. An additional 294 gm of mainly neopentyl glycol was removed at 188 to 224C and gradually increasing vacuum from about 200 to 0.15 mm Hg over 1.8 hours. The clear water white oligomer was poured into a tin foil lined glass tray where it cooled to a brittle, clear solid. The hydroxyl number of this oligomer was determined to be 50.8 indicating a molecular weight of 2208.
B.) 20.62 gm (.0905 mols) bisphenol-A, 20.0 gm (.0090 mols) of the above oligomer, 31.64 gm (.0995 mols) of diphenyl terephthalate and 0.16 gm lithium hydride were reacted together at 260C for 5.75 hours with stirring and under vacuum ranging from about 200 mm initially to 0.15 mm Hg ,.~, . .
~ ~ 20 finally. The polymer removed from the reactor is clear, yellow and tough. `
i 18.38 gm or about 98.3% of the theoretical phenol was recovered (and identity ,. .
confirmed by nmr in CDC13). The intrinsic viscosity of the polymer (CHC12-CHC12, 25C) is 0.996. The Tg determined as in Example 2 was 130-137C.
The polymer was molded and tested for microtensile impac-t as described above ; 25 and gave a value of 6.3 inch-lb, i.e. relative by high impact.
: .
Example 8 An oligomer was prepared as in the above example with 10.45 mols neopentyl glycol, 4.937 moles dimethyl terephthalate and .48 gm tetrabutyl tilanate. Approximately 400 mls of methanol and 353 gm neopentyl glycol . . .
- 3~ were recovered. The oligomer was clear, water white and brittle and found to have a hydroxyl number of 135 i.e. MW 832.

' . ~ . . . .

0.0452 mole bisphenol-A, 0.0120 moles of the above oligomer, 0.0572 moles diphenylterepthalate and 0.13 gm ~1 drop) tetrabutyl titanate were reacted at 4 hours at 260C and 1 hour at 290C with stirring and under a vacuum which was gradually increased to 0.1 mm Hg. 10.7 gm (99.5% of theory) phenol was recovered. The intrinsic viscosity of the polymer (CHC12CHC12, 25C) ; is 0.58. The polymer is clear and tough.
Example 9 A~ oligomer was prepared from 3.5~ moles neopentyl glycol, 1.68 moles dimethyl terephthalate and 0.16 gm tetrabutyl t;tanate as described above~
129 mls methanol and 162 gm neopentyl glycol were recovered. The oligomer was clear and brittle and found -~o have a hydroxy number of 66.3 and a ~; corresponding molecular weight of 1692, ; 0.0904 moles bisphenol-A, 0.0119 moles oF the above oligomer, 0.1025 ?
-~ moles diphenyl terephthalate and 0.026 gm (2 drops) of tetrabutyl titanate were reacted at 260C (approx. 3.5 hours) and 290C (approx. 1.5 hours) with stirring and under a gradually ;ncreasing vacuum (max.=.l mm Hg).
17.1 gm or 83.8% of the theoretical phenol was recovered. The polymer is . .
clear and tough. Intrinsic viscosity: 0.805 (CHC12CHC12, 25C).
~-~ Example 10 2Q .905 moles bisphenol-A, .0090 moles of the oligomer from example 7~
0.995 moles diphenyl terephthalate and 0.32 gm antimony oxide were reacted together at 300C for approximately 5 hours with stirring and under a gradu-ally increasing vacuum (finally 1 mm Hg). The product is clear, yellow and tough. Intrinsic viscosity: 0.679 (C~C12CHC12, 25C). The Tg as de-termined in Example 2 was lZ3-132C. GPC: MW/Mm = 64,000/1~,900 = 3.22.
The polymer was molded and found to have a tensile impact of 1.$1 inch-~pound. ~;
Example 11 ,~
3.14 mols neopentyl glycol, 1.43 mols dimethylterephthalate and .14 gm -(12 drops) tetrabutyl titanate ~lere reacted together as described above.
- 30 Approximately 92 gm methanol and 167 gm neopentyl glycol were removed. The product is clear, very light and brittle. Based on the amount of neopentyl removed, the MW was estimated at 4600.

~ ' ' . ~' ~1;)132399 45 grams of the above oligomer and 0.26 ym (2 drops) of tetrabutyl titanate were reacted at 265C for 3.5 hours with stirriny and a vacuum of 1 mm Hg. At this point the vacuum was released with dry n1trogen gas and 0.193 mols bisphenol-A, 0.193 mols diphenyl terephthalate and 0.026 gm tetrabutyl titanate were charged to the reactor. The reaction was continued with stirring at 260C (1.2 hours) and 290C (l.l hours) and the vacuum ; gradually decreased to less than 1 mm Hg. The polymer is clear and tough.
Intrinsic viscosity: 0.58 in CHC12CHC12, 25C.
Examp-l--e--l-?-An oli~omer was prepared by reacting 3.292 mols neopentyl glycol with 1.646 mols dimethyl terephthalate and 0.16 gm zinc acetate 2H20 for approximately 4 hours at 200-240C, during which time 124 mols of methanol was collected. The oligomer has a hydroxyl number of 304 which indicates MW of 369.
20.0 gm of the above oligomer, 20.62 bisphenol-A, 45.98 gm diphenyl : .
' terephthalate and 0.0115 gm LiH are charged to a small glass tube reactor, put under a blanket of dry nitrogen and heat (with stirring) to 260C
for 3.3 hours during which ti~e vacuum i5 applied and increased gradually :1 .
-~ to 1 mm Hg. The mixture is then heated to 290C for 1.5 more hours under full vacuum. The polymer is then removed from the reactor.
l The polymer is clear, light yellow and very tough. The intrinsic j viscosity is determined to be 0.633 in CHC12CHC12 at 25C. The Tg asmeasured according to Example ? was 119-127C. When the polymer was molded and tested as set forth in Example 2, the molded specimen exhibited , 25 an impact strength of 8.9 inch/pound.
The polymers prepared in examples 8 through 11 had the properties shown in Table I.
. .
Various changes and modifications can be made in the process and products of this invention without departiny from the spirit and the scope thereof.
! :
The various embodiments set forth herein were for the purpose of further illustrating the invention but were not intended to limit it.

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Claims

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

A melt polymerization process for the preparation of linear aromatic polyesters which comprises (a) mixing a bisphenol of the formula wherein Ar is aromatic, G is a radical selected from the group consisting of alkyl, haloalkyl, aryl, haloaryl, alkylaryl1 halo-alkylaryl, arylalkyl, haloarylalkyl, cycloalkyl and cyclohalo-alky1; E is divalent radical selected from the group consisting of alkylene, haloalkylene, cycloalkylene, halocycloalkylene, arylene, haloarylene, -O-, -S-, -SO-, -SO2-, -SO3-, -CO-, O or ; T and T' are independently selected from the group consisting of halogen, G or OG; m is an integer from 0 to the number of replaceable hydrogen atoms on E; b is an integer from 0 to the number of replaceable atoms on Ar, and X is 0 or 1;
a diaryl ester of a carboxylic acid of the formula wherein R and R' are the same or different aryl groups; X is oxygen or sulfur, Z is alkylene, -Ar- or Ar - Y - Ar where Ar is aromatic, Y is alkylene of 1-10 carbon atoms, haloalkylene, -O-, -S-, -SO-, -SO2-, -SO3-, -CO-, = O or , where G is selected from the group consisting of alkyl, haloalkyl, aryl, haloaryl, alkylaryl, haloalkylaryl, arylalkyl, haloarylalkyl, cycloalkyl and cyclohalo-alkyl; and n is 0 or 1;
and an oligomer of a dialkyl ester of a dicarboxylic acid and a diol; and (b) reacting the mixture in the presence of a trans-esterification catalyst at a temperature of about 150°C. to 380°C.

The process of claim 1 wherein said diol contains 2 to about 20 carbon atoms.

The process of claim 1 wherein the oligomer is prepared by reacting a dialkyl ester of an aromatic dicarboxylic acid and a diol.

The process of claim 1 wherein the aryl moieties of the diaryl ester are selected from phenyl, alkylphenyl, halophenyl and nitrophenyl.

The process of claim 3 wherein the alkyl moieties of the dialkyl ester have 1 to 10 carbon atoms.

The process of claim 1 wherein the bisphenol is bisphenol-A.

The process of claim 1 wherein the dicarboxylic acids are isophthalic acid, terephthalic acid or mixtures thereof.

The process of claim 2 wherein the glycol is neopentyl glycol.

The process of claim 1 wherein said diol is a polyalkylene ether or ester glycol.

The process of claim 9 wherein the glycol is polyethylene glycol.

A process for the preparation of linear aromatic polyesters which comprises (a) mixing bipshenol-A, a diphenyl terephthalate, and an oligomer of terephthalic acid and neopentyl glycol; and (b) reacting the mixture in the presence of a transesterification catalyst at a temperature of about 150 to 380 degrees centigrade.

The process of Claim 11 wherein the oligomer is prepared by reacting dimethyl terephthalate with neopentyl glycol.

The linear aromatic polyester prepared by the melt trans-esterification and polycondensation of a bisphenol of the formula ) wherein Ar is aromatic, G is a radical selected from the group consisting of alkyl, haloalkyl, aryl, haloaryl, alkylaryl, halo-alkylaryl, arylalkyl, haloarylalkyl, cycloalkyl and cyclohaloalkyl;
E is a divalent radical selected from the group consisting of alkylene, haloalkylene, cycloalkylene, halocycloalkylene, arylene, haloarylene, -O-, -S-, -SO-, -SO2-, -SO3-, -CO-, = O or ; T and T' are independently selected from the group consisting of halogen, G or OG; m is an integer from 0 to the number of replaceable hydrogen atoms on E; b is an integer from 0 to the number of replaceable atoms on Ar, and x is 0 or 1, a diaryl ester of a dicarboxylic acid of the formula wherein R and R' are the same or different aryl groups; X is oxygen or sulfur, Z is alkylene, -Ar- or Ar-Y-Ar where Ar is aromatic, Y
is alkylene of 1-10 carbon atoms, haloalkylene, -O-, -S-, -SO-, -SO2-, -SO3-, -CO-, = O or , where G is selected from the group consisting of alkyl, haloalkyl, aryl, haloaryl, alkylaryl, haloalkylaryl, arylalkyl, haloarylalkyl, cycloalkyl and cyclohalo-alkyl; and n is 0 or 1; and an oligomer of a dicarboxylic acid and a diol having a degree of polymerization of at least about 8.

The polyester of claim 13 wherein said dicarboxylic acid of said oligomer has the formula:
wherein Z is alkylene, -Ar or -Ar - Y - Ar where Ar has the same definition as given with respect to the bisphenols, Y is selected from the group consisting of alkylene, haloalkylene, -O-, -S-, -SO2-, -SO3-, -CO-, = O and ; where G is selected from the group consisting of alkyl, haloalkyl, aryl, haloaryl, alkylaryl, haloalkyl-aryl, arylalkyl, haloarylalkyl, cycloalkyl and cyclohaloalkyl, and n is 0 or 1.

The polyester of claim 14, wherein said diol contains 2 to about 20 carbon atoms.

The polyester of claim 14 wherein said diol is a polyalkylene ether or ester glycol.

The linear aromatic polyester prepared by the melt trans-esterfication and polycondensation of bisphenol-A, diphenyl tere-phthalate and an oligomer of terephthalic acid and neopenyl glycol having a degree of polymerization of at least about 8.