POLYESTERCARBONATE COMPOSITION

Abstract: A composition comprising a copolyestercarbonate derived from a dihydric phenol, a carbonate precursor, and an aliphatic alpha omega dicarboxylic acid or ester precursor wherein the dicarboxylic acid or ester precursor has from 10 to about 20 carbon atoms, inclusive, and is present in the copolyestercarbonate in quantities of from about 2 to 30 mole percent of the dihydric phenol.

Description: Polyestercarbonate composition. This application is a cont inuation-in-part of co-pending U.S. Serial No. 07/476,068 filed January 30, 1990 which is a continuat ion-in-par of co-pending U. S. Serial No. 07/455,118, filed December 22, 1989. BACKGROUND OF THE INVENTION Polycarbonates are well known as a tough, clear, highly impact resistant thermoplastic resin. However the polycarbona es are also possessed of a relatively high mel viscosity. Therefore in order to prepare a molded article from polycarbonate, relatively high extrusion and molding temperatures are required. - Various efforts throughout the years to reduce the melt viscosity while also maintaining the desired physical properties of the polycarbona es have been attempted. These methods include the use of plas ticiz ' ers , the use of aliphatic chain stoppers, reduction of molecular weight, the preparation of bisphenols having long chain aliphatic substituents and various polycarbonate copolymers as well as blends of pol carbona e with other polymers. With respect to plas icizers , these are generally used with thermoplastics to achieve higher melt flow. However usually accompanying the plasticizer incorpora ion into polycarbona e compositions are undesirable features such as embri t t lement and fugitive characteristics of the plasticizer. Increased flow, can be- fairly readily obtained with the use of aliphatic chain stoppers, however impact resistance as measured by notched izod drops significantly. Embri t lement may also be a problem. When utilizing a bisphenol having a lengthy aliphatic chain thereon, increases in flow can be observed. However these are usually accompanied by substantial decreases in the desirable property of impac t s trength . Reducing the molecular weight of polycarbona e has also been useful to increase flow for applications requiring thin wall sections. However, molecular weight reduction is limited in the extent that it can be practiced before properties such as ductility and impact strength are severely hampered. Blends of polycarbonate with other polymers are useful to increase melt flow, however the very useful property of transparency is generally lost. With respect to polycarbonate copolymers it has been well known that a reduced glass transition temperature Tg, can be obtained by introducing aliphatic ester fragments into the polycarbonate backbone. Examples of this work go back as early as the original copolyes ercarbonate patent of Goldberg, USP 3,169,121 wherein at column 3, line 64 to column 4, line 41 various aliphatic dibasic acids are disclosed as being appropriate for usage in making copolyester- carbonates. Reduced softening points are noted. At column 4, line 11, azelaic and sebacic acids are disclosed. At column 7, example 4, a 50 mole percent ester content bisphenol-A copolyestercarbonate based on bisphenol-A using azelaic acid as the ester linkage is disclosed. Various other patents since that time have broadly disclosed the use of aliphatic acids in the preparation of copolyestercarbonates for example USP 3,030,331, 4,238,59.6, 4,238,597, 4,504,634, 4,487,896 and 4,252,922. Kochanowski USP,4 , 286 , 083 , specifically refers to the making of a copolyes ercarbonate utilizing bisphenol-A, azelaic acid and phosgene in example 6 at column 9. 25 mole percent of the azelaic acid, based on the moles of bisphenol-A, was contacted with the bisphenol-A together with phenol as a chain stopper, and triethyla ine as a catalyst in an inter- facial reaction with phosgene wherein the pH was main¬ tained at 6 over a period of 35 minutes and then raised to 11.4 for a period of 36 minutes. Generally these copo lyes terca rbona tes with aliphatic linkages have sig¬ nificantly lowered Tgs than the polycarbona e and there¬ fore are processable at lower temperature. However, these polymers as in Kochanowski do not have other physical properties reported, in particular impact resistance or impact resistance under various environ¬ mental conditions such as heat aging and/or reduced te pe ra ture . Chain stoppers have been utilized in making polymers for many decades. The function of the chain stopper in the preparation of the polymer is to control the molecular weight. Generally these chain stopping compounds are mono func t iona 1 compounds similar to the func onality of a repeating unit of the polymer. For quite some time scant attention was directed to the structure of the chain stopping agent other than it be reactive with the monomer unit during the preparation of the polymer and be compatible with the polymer. In the last few years more attention has been directed to the structure of the chain stopper. It has been found that the structure of the chain stopping compound can signi¬ ficantly effect the property spectrum of the polymer. For many years , phenol had been the standard chain stopping agent used in the preparation of polycarbonate. At times para er arybutylphenol was employed as a chain stopping agent. Lately more attention has been focused on other materials for preparation of the polycarbonate. USP 4,269,964 , disclosed the usage of isooctyl and isononyl substituted phenols as chain stoppers for poly- carbonate. Additionally paracum lphenol and chromanyl compounds have been utilized to chain stop poly¬ carbonates. Both the paracum lphenol and chromanyl compounds have been utilized to chain stop copolyester- carbonates wherein there is a totally aromatic molecule with high ester content , see USP 4,774,315 and 4,788,275. Accompanying the usage of the larger sized endgroups has been the ability to obtain the same or essentially the same physical characteristics of the polycarbonate but at a lower molecular weight. This lower molecular weight provides better flow than a polycarbonate of a higher molecular weight. However these systems reach a point wherein the chain stopping agent cannot solve the problems caused by utilizing a shorter chain length i.e. lower molecular weight polycarbonate. Embri tt lement occurs , therefore there still exists a need for a polymer having lower processing temperature but which is accompanied by subs antially increased flow and essentially the full spectrum of polycarbonate properties. A new polymer system has now been discovered which manages to combine excellent processabi1ity due to its extremely high melt flow with essentially maintained physical properties such as toughness , transparency, and impact resistance. SUMMARY OF THE INVENTION In accordance with the invention there is a com¬ position comprising a copolyes ercarbonate polymer derived from a dihydric phenol, a carbonate precursor and an aliphatic alpha omega dicarboxylic acid or ester precursor wherein the dicarboxylic acid has from ten to about twenty carbon atoms , inclusive and the dicar¬ boxylic acid is present in the copolyes ercarbonate in quantities of from about 2 to 30 mole percent of the dihydric phenol. A further aspect is the copolyestercarbonate of the invention extended to include dicarboxylic acids of 8 and 9 carbon atoms , which is endcapped with a monophenolic compound which provides the copolyester¬ carbonate with better Notched Izod impact resistance and ductility after aging than the phenol endcapped copol es erc rbo ate. -5- DETAILED DESCRIPTION OF THE INVENTION Dihydric phenols which are useful in preparing the copolyes ercarbonate of the invention may be represented by the general formula Figure l where in : R is independently selected from halogen, monovalent hydrocarbon, and raonovalent hydrocarbonoxy radicals ; is independen ly selected from halogen, monovalent hydrocarbon, and monovalent hydroca rbonoxy radical s ; W is selected from divalent hydrocarbon 0 0 0 II |l ιl radicals, -S-, -S-S-.. -0-, -S-, -S-, and -C- ; ιl 0 n and n are independently selected from integers having a value of from 0 to 4 inclusive; and b is either zero or one. The monovalent hydrocarbon radicals represented by R and R 1 include the alkyl , cycloalkyl, aryl , aralkyl and alkaryl radicals. The preferred alkyl radicals are those containing from 1 -to about 12 carbon atoms. The preferred cycloalkyl radicals are those containing from 4 to about 8 ring carbon atoms. The preferred aryl radicals are those containing from 6 to 12 ring carbon atoms , i.e. , phenyl , naphthyl , and biphenyl. The preferred alkaryl and aralkyl radicals are those containing from 7 to about 14 carbon atoms. The preferred halogen ' radicals represented by R and R are chlorine and bromine. The divalent hydrocarbon radicals represented by W. include the alkylene, alkylidene, cycloaIkylene and cycloalkylidene radicals. The preferred alkylene radicals are those containing from 2 to about 30 carbon atoms. The preferred alkylidene radicals are those containing from 1 to about 30 carbon atoms. The preferred eyeloaIkylene and cycloalkylidene radicals are those containing from 6 to about 16 ring carbon atoms. The monovalent hydrocarbonoxy radicals represented by R and R 1 may be represented by the formula - OR 7 wherein R 2 is a monovalent hydrocarbon radical of the type described hereinafore. Preferred monovalent hydrocarbonoxy radicals are the alkoxy and aryloxy radicals. Some illustrative non-limiting examples of the dihydric phenols falling within the scope of Formula II inc1ude : 2 , 2-bis (4-hydroxyρhenyl )propane (bisphenol-A); 2,2-bis(3,5-dibromo-4-hydro ypheπyl)propane; 2, 2-bis ( 3, 5-dime hy1-4-hydroxyphenyl)propane; l,l-bis(4-hydroxyphenyl)cyclohexane; l,l-bis(3,5-dime hyl-4-hydroxyphenyl)cyclohexane; 1 , l-bis(4-hydroxyphenyl) " dec ne; l,4-bis(4-hydroxyphenyl)propane; l,l-bis(4-hydroxyρhenyl) yclododecane; 1 , 1-bis (3, 5-dime thy1-4-hydroxyphenyl)eyelododecane; 4,4 -dihydroxydipheny1 ether; 4,4 -thiodiphenol ; 4,4 -dihydr xy-3 , 3 -dichlorodipheny1 ether; and 4,4 -dihydroxy-2 , 5-dihydroxydipheny1 ether. Other useful dihydric phenols which are also suitable for use in the preparation of the above polycarbona es are disclosed in U.S. Patent Nos. 2,999,835; 3,028,365; 3,334,154; and 4,131 ,575 , all of which are incorporated herein by reference. The carbonate precursor utilized in the invention can be any of the standard carbonate precursors such as phosgene, diphenyl carbonate and the like. When using an interfacial process or a bi sch loroforma e process it is also preferred to use a standard catalyst system well known in the synthesis of polycarbonates and copoly¬ estercarbonate s . A typical catalyst system is that of an a ine system such as tertiaryamine , amidine or guanidine. Tert iaryamines are generally employed in such reactions. TriaIky lamines such as triethylamine are generally preferred. The monomer which supplies the ester units in the copolyestercarbonate is an aliphatic alpha omega dicarboxylic acid from 10 to about 20 carbon atoms preferably 10 to 12 carbon atoms. The aliphatic system is normal , branched or cyclic. Examples of the system include sebacic acid, dodecanedioic acid, C14, C18 and C20 diacids. The normal saturated aliphatic alpha omega dicarboxylic acids are preferred. Sebacic and dodecane- dioic acid are most preferred. Mixtures of the diacids can also be employed. It . should be noted that although referred to as diacids , any ester precursor can be employed such as acid halides, preferably acid, chloride , diaromatic ester of the diacid such as diphenyl, for example the diphen lee er of sebacic acid. With reference to the carbon atom number earlier mentioned, this does not include any carbon atoms which may be included in the ester precursor portion, for example diphenyl. The copolyes ercarbonates of the invention can be prepared by the known methods, for example those appearing in Quinn 4,238,596 and Quinn and Markezich 4,238,597. Examples of such processes include the formation of acid halides prior to the reaction of the ester forming group with the dihydric phenol and then followed by phosgenation . Still further, the basic solution process of Goldberg in the 3,169,121 reference utilizing a pyridine solvent can also be employed while also using the dicarboxylic acid per se. A melt process utilizing the diesters of the alpha omega dicarboxylic acids can also be employed. An example of such a compound is the diphenylester of sebacic acid. After substantial experimentation, it has been found that a preferred process for making the copoly- es tercarbonates of this invention exists. The process of Kochanowski , USP 4,286,083 (083) was initially utilized and then improved upon. It was found that lower diacids such as adipic acid were not incorporated into the polymer backbone to any great extent. Rather, one had to go up to higher carbon atom dicarboxylic acids before any significant incorporation of diacid into the backbone was observed. We have found that the dihydric phenol and alpha omega diacid should be phos- genated at a pH of at about 8 to 9 for about 70 to 95% of the phosgenation. Following that, the pH of the reaction should be raised to a level of about 10 to 12 preferably 10.2 to 11.2 for the remainder of the phos- genation. A preequilibration of the reactants , other than phosgene, at the initial reaction pH, 8 to 9, preferably 8 to 8.5, for a period of time, for example 3 to 10 minutes, seems to improve the incorpora ion of the diacid into the polymer. On a lab scale wherein the mixing is not as effective as in a resin reactor, dodecanedioic acid appears to incorporate better when it is used in fine particle size, for example about 50 to 300 mesh. In performing this interfacial reaction, the reactor should also contain a catalytic quantity of an amine, preferably t rie thy lamine . Amine catalys-t with a range of about 0.75 to about 3 mole percent based on the dihydric phenol content can be employed. Further experimentation has shown that reaction time can be substantially reduced and the diacid totally or substantially incorporated within the copolyester¬ carbonate as well by utilizing in the interfacial reaction a solution of the dicarboylic acid salt. That is , a solution of the dicarboxylic acid salt is charged to the reactor rather than the dicarboxylic acid per se. Acids of 10 carbon atoms or greater are preferred. It is of course , preferred to prepare a solution of the same dicarboxylic acid salt as is being utilized as the aqueous medium in the interfacial reaction. For example when aqueous sodium hydroxide is used as the aqueous phase in the interfacial reaction as well as control the pH of the reaction, the sodium salt of the dicarboxylic acid is prepared. Other salts can be used such as prepared from potassium, calcium and the like. This is simply done by contacting the diacid, usually in its solid form, with aqueous sodium hydroxide and pumping that solution into the reactor. The dihydric phenol can be already present together with the aqueous base and endcapping agent. The carbonate precursor such as phosgene is added and the reaction allowed to proceed. Interestingly with the use of the diacid salt solution the aforementioned pH periods are substan- tially changed. A period of time at a high pH, about 10 to 12, should still be used to obtain the desired product. However the quantity of time at the lower pH, 8 to 9 can be significantly reduced. For example when the entire reaction was run at pHIO with previously prepared sodium dodecaned ioa e for a period of only twenty minutes, 99 percent of the acid was incorporated into the copolyestercarbonate. When only 25% of the twenty minute reaction period was held at pH8, the remaining 15 minutes at pHlO , and utilizing the previously prepared sodium dodecanedioate 100% of the acid was incorporated into the copolyestercarbonate. Therefore, anywhere from about 0 to about 95% of the carbonate precursor addition time should be run at about pH8 to 8.5 with the remainder of the carbonate precursor addition time being at a pH of about 10 to 12. Preferably the intitial period of carbonate precursor addition is from about 5 to 85%. In order to control molecular weight, it is standard practice to utilize a chain stopping agent which is a monofunctional compound. This compound when reacting with the appropriate monomer provides a non- reactive end. Therefore the quantity of chain stopping compound controls the molecular weight of the polymer. Bulkier chain terminators than phenol should provide substantially better physical properties such as low temperature impact. Examples of these bulkier substituents include paratertiarybutylpheno1 , isononyl phenol, isooctyl phenol, cumyl phenols such as meta and paracumyl phenol, preferably paracumyl phenol, as well as chromanyl compounds such as Chro an I. The copolyestercarbonate of this invention with the standard endcapping reagent posseses a substant ally lowered glass transition temperature, Tg , therefore providing processabi lity at a lower temperature. Sur- prisingly accompanying this lower temperature processa- bility are substantially equivalent physical properties as a standard polycarbonate of the same intrinsic viscosity as the inventive composition and very high flow rates. When utilizing the bulkier endgroups, it is possible to achieve even lower molecular weight copoly¬ estercarbonate while maintaining excellent physical properties such as aged impact resistance and/or low temperature impact resistance while having a very high flow rate. This allows the copo lyes ercarbon es of this invention to be utilized where the charac eris cs of polycarbonates such as clarity, impact resistance, modulus , and overall toughness are required but must also be present in increased proce s sabi li ty through an enhanced flow rate. Such applications include optically pure materials such as audio discs, digital discs, other media storage devices , packaging materials , other thin walled parts and films, optical discs including fiber optics and the like. The aliphatic alpha omega dicarboxylic acid ester is present in the copolyes ercarbon e in quantities from about 2 to 30 mole percent , baaed on the dihydric phenol. Generally with q .. * ιtitieβ below about 2 mole percent the Tg is insufficiently lowered and signifi¬ cantly altered flow rate is not observed. Above about 30 mole percent , the physical properties of the copoly- es tercarbona e are significantly hindered in comparison to the polycarbona e without the aliphatic ester linkages. Preferred mole ptrcentβ of aliphatic alpha omega dicarboxylic acid ester are from about 5 to 25 and more preferably about 7 Co 15 mole percent of the dihydric phenol. The weight average molecular weight of the copoly¬ es ercarbonate can generally vary from about 10,000 to about 100,000 as measured by GPC using a polystyrene standard, corrected for polycarbonate. A preferred molecular weight is from about 18,000 to about 40,000. EXAMPLE 1 A • Preparation of Copolyestercarbonate with Sebacic Acid and Step Wise pH Process To a 100-liter, glass vessel was added deionized water (30 L) , methylene chloride (35 L) , b β phenol -A (BPA) (11.34 Kg, 49.68 mo 1 ) , £-cumyi phenol (319 g, 1.50 mol) , triβthylaraine (70 L, 0.90 βol) , sebacic acid (1005 g, 4.97 mol), and sodium gluconate (17.5 g). Phosgene was introduced to ' the reaction mixture at a rate of 150 g/min for 34 min (6600 g, 66.73 mol) while maintaining a pH range of 8.0-8.5. The pH was adjusted to 10.0 and the phosgenation continued for 10 min. The phosgene free solution was diluted to 10% solids with the addition of methylene chloride (ca. 45 L) and the polymer solution was extracted until solution organic chloride levels were non-detectable and triethylamine content was less than 1 ppm. The extracted polymer solution was isolated by steam precipitation at a 1.9 L/min feed rate and 100 psig stream feed pressure. The water wet, coarse powder was chopped in a Fitzmill to achieve a more uniform particle size and dried in a hot nitrogen fed fluid bed drier with the temperature at 110°C maximum. The copolyestercarbonate resin had a Tg of about 128°C. Standard polycarbonate has a Tg of 150°C. Extrusion at 230°C and molding at 275°C yielded a transparent material which exhibited improved flow and at 300°C (g/10 min) processability , MFI » 15, as well as excellent mechanical properties. The 1/8" notched izod was 880 J/M, the DTUL measured at 1.8s MPa was 119°C. B. Preparation, of Copo'lyestercarbonate with the Earlier Prepared Salt of DDDA The diβodium salt of dodecanedioic acid (DDDA) was generated by dissolving the free acid (7.2 g, 31 mmol) and NaOH pellets (2.7 g, 68 mmol) in water (180 mL). A 2000 mL five neck Morton flask equipped with a bottom outlet was fitted with a mechanical stirrer, a pH probe, an aqueous sodium hydroxyde (50%) inlet tube, a Claisen adapter to which dry ice condenser was attached, and a gas inlet tube. The flask was charged with bisphenol A (71 g, 311 mmol) , trieth lamine (0.9 mL) , p-cumylphenol (2.0 g, 9 mmol), methylene chloride (220 mL) , and the disodium salt solution of DDDA described above. Then phosgene was introduced at a rate of 2 g/min, while the pH was maintained at'8 by addition of caustic for 10 minutes; the pH was then raised and maintained at around 10.5 while phosgene addition continued for. 10 additional minutes. The total amount of phosgene added was 40 g (400 mmol). The pH was adjusted to 11-11.5 and the organic phase was separated from the brine layer and washed with 2% hydrochloric acid (3' x 300 mL) , and with deionized water (5 x 300 mL) . The brine layer was acidified to pH 1 with concentrated HCl and no unreacted DDDA precipita ed. The solution was dried (MgSO^) , filtered, and then precipitated into methanol (1500 mL) . The resin was washed with methanol (1 x 500 mL) and deionized water (4 x 500 mL) , and dried at 100°C for 15 hours. EXAMPLES 2-6 To a 100-liter, glass vessel was added deionized water (30 L) , methylene chloride (35 L) , BPA (11.34 Kg, 49.68 mol) , £-cumyl phenol ' (319 g, 1.50 mol) , triethyl- amine (70 mL, 0.90 mol) , dodecanedioic acid (1155 g, 4.97 mol) , and sodium gluconate (17.5 g). Phosgene was introduced to the reaction mixture at a rate of 150 g/min for 34 min (6600 g, 66.73 mol) while maintaining a pH range of 8.0-8.5. The pH was adjusted ' to 10.0 and the phosgenation continued for 10 min. The phosgene free solution was diluted to 10% solids with the addition of methylene chloride (ca. 45L) and the polymer solution was extracted until solution organic chloride levels were non-detectable and trie thy lamine content was less than 1 ppm. The extracted polymer solution was isolated by steam precipitation at 1.9 L/min feed rate and 100 psig stream feed pressure. The water wet, -coarse powder was chopped in a Fitzmill to achieve a more uniform particle size and dried in a hot nitrogen fed fluid bed drier with the temperature at 110°C maximum. The copolyestercarbonate resin had a Tg of about . 125°C. Extrusion at 250°C and molding at 275°C yielded a transparent material which exhibited improved flow and processabi1i y , MFI * 13 at 300°C (g/10 min), compared to standard polycarbonate of similar or same molecular weight, as well as excellent mechanical properties. The 1/8" Notched Izod was 880 J/M, the DTUL measured at 1.82 MPa was 119°C. Copolymers of various intrinsic viscosities containing 10 mo1% dodecanedioy1 ester were prepared according to this procedure. The copolyestercarbonates were paracumy1phenol-endcapped . The copolyester- carbonates were compared to standard commercial grade BPA polycarbonates, Lexan 125, 145, and 135 prepared by GE Plastics, all of which were phenol end-capped, as well as stearic acid endcapped polycarbonate (SAPC) of a similar intrinsic viscosity. All materials were stabilized with 0.05 weight percent of a phosphite. TABLE Example SAPC SAPC 125 145 135 IV (dl/g) 0.51 0.48 0.53 0.62 0.48 0.53 0.48 0.52 0.63 MFI (g/10min)at 300°C 32 46 27 13 34 19 18 11 5 Tg (C) 124 124 123 127 126 131 149 149 150 HDT( 1.82 MPa)°C 116 117 118 119 116 123 138 140 142 INI* (j/m) 781 704 772 883 64(B) 96(B) 728 770 875 Tens Y (N/mm) 56.4 57.4 56.3 55.4 62.1 62.6 61.5 60.7 59.1 Z Elongation 130 81 120 150 103 104 129 110 98 ♦Notched Izod In general the copo lyes tercarbona tes of the invention have substantially lower glass transition temperatures and heat deflection temperatures than the standard polycarbonates. In fact they were very similar to the stearic acid endcapped polycarbonate comparative examples. However these stearic acid endcapped materials were extremely embrittled in comparison to the normal polycarbonate and the copolyes tercarbon tes of the invention. The invention materials demonstrated outstanding flow relative to the standard poly¬ carbonates while achieving equivalent impact resistance. In the Table below., Example 4 of the invention is compared to a standard BPA polycarbona e but containing either 7 weight percent of a diphosphate plasticizer or in admixture with a 10 wt.% of polybutylene tereph ha late . Example IV Tg MFI (g/lOmin) 125 NI Transmission 300°C (J/M) 4 0.48 7% CR733S 0.50 10% PBT BLEND 0.49 * D is a ductile break, B is a brittle break As is clearly observed from the above data, the presence of the plasticizer or the polyester brings about similar flows and transparancies but seriously embrittles the polycarbonate in comparison to the copolyester- carbonate of the invention. EXAMPLES_7-9 Following procedures similar to Example 2, bisphenol-A copo lyes terearbonates incorporating the same quantity of dodecanedioic acid and varying quantities of p-cumylphenol endcapper were prepared. The properties of these paracumy 1 -endca pped copolyeβter- carbona tes' were compared to a paracumy Ipheno I endcapped bisphenol-A polycarbonate control . The results are provided below wherein there is 10 mole percent dodecane- dioic acid ester in the copolyestercarbonate, I.V. is intrinsic viscosity measured at 25°C in methylene chloride, Mw is weight average molecular weight measured by GPC. MFI is Melt Flow Index at 300°C (g/10 min). Y.I. is yellowness index measured according to ASTM D1925, and N.I. is notched izod impact strength measured according to ASTM D256 at room temperature (RT) and -10°C. All breaks were 100% ductile of all five samples except for control at -10°C which was 100% brittle. Exam le * As is observed from the above results, standard "high flow" paracumy 1 pheno 1 endcapped polycarbonate , the control, exhibited reasonable flow, MFI* 22, at a molecular weight of about 22 ,000. However, the Notched Izod at -10°C is low and completely brittle. The copolyes te rcarbona es of the invention, however, can have literally more than twice the flow, MFI-48 at almost the same molecular weight and are accompanied by high impact strength with complete ductility , even at the reduced temperature of -10°C. SUBSTITUTESHEET The essence of the invention is the insertion of the aliphatic alpha omega dicarboxyla te unit into the polycarbonate , thereby providing a copolyestercarbonate having repeating units of the structure Figure 2 where R, R , n, n , W and b have been previously described and X is an aliphatic grouping of about 8 to about 18 carbon atoms , inclusive. The d repeating unit is present in the copolyestercarbonate in from about 2 to 30 mole percent of the total of the repeating units c+d , X is preferably about 10 to 18 carbon atoms, inclusive. The aliphatic system is preferably saturated and is normal , branched, cyclic or alkylene substituted cyclic. The mole percent of d is preferably about 5 to 25 and more preferably about 7 to 15 mole percent. As shown in this specifica ion, the copolyester carbonates of this invention essentially maintain a signi¬ ficant portion of the physical properties of polycarbona e of similar or same molecular weight but achieve these, except those related to Tg such as HDT, with reduced processing requirements since the Melt Flow Index for these new materials is substantially raised. Perhaps the most significant property maintained and in some cases even improved is the 1/8 inch Notched Izod impact strength. Similarly, copolyes tercarbonates of this invention which have the same proces sabi 1 i ty as standard polycarbonates can have signi ficant ly higher molecular weights and resulting property enhancements . Thus , a further aspect of this invention is a method for using the above identified invention composi ions ' . This is a method for processing resins which comprises processing a copolyestercarbonate of the above invention wherein the copolyestercarbonate is processed at a temperature significantly lower and with lesa work, as shown by a higher melt flow index than the same aromatic polycarbon te without ester units and of the same weight average molecular weight. Any type of processing operation is included for example , injection molding, rotary molding, blow molding, compression molding and extrusion processes such as sheet and film extrusion, profile extrusion, coextrusion and general compounding. Injection molding and extrusion are preferred. When referring to the "polycarbonate of same or similar molecular weight" or "standard polycarbonate" reference is made to the polycarbona e made from the same dihydric phenol but without aliphatic ester repeat units . Further examples of extruded articles of the copolyestercarbonate of the invention include ordinary sheet articles, as veil Λ » multi walled sheet and film. Generally the thickness of an extruded article which is of maximum thickness to be called "film" is about 0.5-1 mm. The extruded articles need not be made of all copolyester¬ carbonate compositions of the invention. Rather such articles can be made from compositions comprising at least 90% by weight of the invention copo lyes ercarbona tes . Other polymers may be present in the composition. Preferred examples of such polymers are polyesters such as the polyalkylene terephth lateβ , preferably polyethylene terephthalate and polybutylene tereph halate , as well as eye lohexanedimethanol (CHDM) containing polyesters. SUBSTITUTE SHEET Examples of such polyesters include polyesters prepared from CHDM and terephthalic acid, mixtures of terephthalic acid and isophthalic acid, mixture of CHDM and alkylene glycol, preferably ethylene glycol, wherein the CHDM is preferably from 20-80 mole% of the glycol present , the remainder being the alkylene glycol, preferably ethylene glycol. The acid portion of the CHDM containing polyesters is terephthalic, isophthalic, mixtures thereof or preferably terephthalic. Examples of such polesters all available from Eastman Chemical are PCT (100% CHDM, terephthalic acid) , PCTG (80% CHDM, 20% ethylene glycol , terephthalic acid) and PETG (80% ethylene glycol, 20% CHDM, terephthalic acid). Thermoformed products are readily prepared from the sheet or fi lm . Surprisingly these extruded film or sheet products show some unexpected advantages as compared to extruded products made out of conventional aromatic polycarbonates such as bisphenol-A polycarbonates. Sheets extruded out of conventional aromatic polycarbonates require a predrying step before they can be thermoformed at elevated temperatures. If they are not predried, bubbling occurs at the surface of the thermoformed sheet . It has been found that sheets extruded out of a thermoplas ic composition baaed on the copolyestercarbonate s of this invention do not. require a predrying step before thermoforming. It has further been found that sheets extruded out of a thermoplas ic composition based on copolyes ercarbonates of this invention are more resistant in the flame retardancy test according to DIN 4102, as compared to sheets extruded out of conventional aromatic polycarbonates. The test according to DIN 4102 is of importance for the building and construction industry. Below are further examples of the invention. These examples are intended to further illustrate the invention. Example 10 Two series of sheets (with a thickness of 3 mi 11 ime t.e rs ) have been manufactured by extrusion on a Werner Pfleiderer twin screw extruder. One series (A) of sheets has been manufactured out of a conventional aromatic polycarbona e derived from bisphenol A and phosgene , with an intrinsic viscosity of 58 ml/g as measured in CH2 CL at 20°C. The second series (B) of sheets has been manufactured out of a copolyestercarbonate according to the invention, with a dodecanedioic (HOOC [CH 3 JQCOOH ) content of 10 mole% based on dihydric phenol plus diacid with an intrinsic viscosity of 58.2 ml/g as measured in CH2 C at 20°C. The sheets were exposed to moisture and then thermoformed with a drying step prior to the the rmo f0 rmi ng or no drying step. The the rmoforming was done on a Geiss 1000 x 600 mm. vacuum forming machine with an aluminium mold , heated to 100°C. The sheets were heated by radiation prior to thermoformin . The radiation temperature is about 25°C above the actual temperature of the sheet. The surface was examined after thermoforming . The exact pre reatment , the radiation temperatures and the observed surface quality are recorded in following table . Table Series Pretreatment Radiation Observations temperature 14 days at relative 212 Bubbling all over humidities varying the formed part , from 58-79%, no diameter 1 to drying prior to 1.5m , average 8 thermoforming bubb les / cm . 180 Forming not possib ie . Dried 24 hours 100 C 212 No bubbles 14 days at relative 180 At all 4 tempera¬ humidities varying 185 tures exce 1 lent from 58-79%, no 190 formability and no drying prior to 195 bubbling visible thermoforming 212 Some bubbling noticed. Dia.meter 0.5mm, average 0.2 bubbles/cm2. Stored 14 days at 180 No bubbles , relative humidity excellent forming. 58-79%, t en put under water during 190 Small bubbles 24 hrs at 21°C, no 0.5mm diam. , 0.3 drying prior to bubbles /cm thermoforming 211 Bubbles 1 -1.5mm , 0.3 bubbles/cm 2 Dried 24 hours 100°C 211 Excellent forming no bubb les . As can be seen from the results reported in the table , the sheet according to the invention can, even when not pre- dried , be formed without bubbles . Additionally it appears that such thermo forming can be carried out at a lower temperature than conventional polycarbonate. Example 11 Sheets with a dimension of 190 x 1000 x 3 (mm) were extruded from a po lyes tercarbonate according to the invention, with a dodecandioic acid content of 10 moleX wi th¬ an intrinsic viscosity of 58.2 ml/g as measured CH 2 CL 2 at 20°C. The sheets were arranged in the lay-out specified for the BI fire test according to DIN 4102, part 1 Brandschacht = chimney- tes t and were tested in unaged condition. During the burning test the sheet according to the invention did not show any gaseous development (bubbles ) within the sheet, the specimen did not get ignited, there were no flaming drips and after the test the remaining length was 70 cm. When sheet extruded out of conventional aromatic poly¬ carbonate are subjected to the same test , some gaseous development (bubbles ) in the sheet occurs , the specimen gets ignited and there are flaming drips. The remaining length is 40-60 cms. Still further, a particularly preferred embodiment of the invention copolyestercarbona e that is the composition of the formula of figure 2 and claim 14 composition wherein there is less than about 0".5 mole%, based on moles of dihydric phenol and diacid in the polymer, of anhydride present in the composition. It has surprisingly been determined that unless the pH ranges are maintained above 10 , preferably about 11 at the latter part of the phosgenation period for a sufficient length of time certain anhydride bonds will be formed and maintained in the polymer. Although most impurities particularly at the low level experienced here do not adversely affect polymeric stability, the anhydride bonds are extremely harmful to the thermal stability of the copo lyes tercarbonates of the invention. The term "anhydride" means the diacid moiety of the polymer which has an anhydride linkage between it and a second acid moiety as illustrated below with dodecanedio ic ac id . 0 0 0 0 -C (CH 2 ) 10 " C - 0 - C - (CH 2 ) 10 C - 0 - These anhydride bonds are formed during the polymeri- zation reaction at the lower pH range. It requires the higher pH range to bring about a rearrangement of the polymer to remove the anhydride linkage ' and bring about a more purified copolyestercarbonate composition. The copolyestercarbonate of the invention should have less than 0.5 mole percent anhydride bonds, preferably less than 0.3 and more preferably leas than 0.1 mole percent anhydride bonds. The anhydride bonds in the polymer can be detected by the use of high field ** H NMR. Such NMR spectra were acquired using a 6 kHz sweep width, a 10s recycle delay, 30°C flip angle , 16k memory size and 32 transients taken on a GE NMR 0mega-300 NMR Spectrometer. The spectrum of a 10 mole % dodecanedioate bisphenol-A copolyestercarbonate prepared at the lower pH and an inadequate amount of time at the higher pH demonstrated anhydride bonds within the polymer. The ester triplet occurred at 2.53 ppm. The anhydride triplet occurred at 2.43 ppm. In each case the triplet is due to the methylene protons immediately adjacent to the carbonyl in the dodecanedio ic acid moiety as shown by the started methylene carbon atom below. 0 * * 0 - 0 - C CH 2 (CH 2 )a - CH 2 - C - 0 - -25- The presence of these anhydride bonds in the copolyestercarbonate polymer are extremely injurious to the thermal stability of the copolyestercarbonate of. this invention. For example , H NMR spectra of powder and extruded pellets from the same lot of resin display different compositions. Under simple extrusion conditions , 230°C, the copolyestercarbonate undergoes thermal degradation that appears to result from the decomposition of the anhydride. Still further, the Table below shows the effect of anhydride bonds upon the melt viscosity as measured by Kasha Index, KI , upon a series of 10 mole percent dodecanedioa e containing bisphenol-A copo1yes terca rbonates with and without the measurable presence of anhydride bonds. KI is measured in the following manner: 7 grams of resin pellets, dried a minimum of 90 minutes at 125°C , are added to a modified Tinius-Olsen model T3 melt indexer; the temperature in the indexer is maintained at 300°C and the resin is heated at this temperature for 6 minutes; after 6 minutes the resin is forced through a 1.048 mm radius orifice using a plunger of radius of 4.737 mm and an applied force of 8.03 kgf; the time required for the plunger to travel 50.8 mm is measured in centiseconds and this is reported as the KI. Copolyestercarbonate Anhydride Bond KI Sample MW Tg Presen 6 Minu e Cen i second A Yea 310 B No 1100 C Yes 400 D No 1700 E Yes 500 F No 3000 As is readily apparent from the data, the presence of the anhydride brings about substantial i r degradation of the polymer under the experimental conditions. I The optimum methods of preparation which minimize the presence of the anhydride bonds , usually below the higher field *H NMR detection limit of 0.1 mole%, is the fo 1 lowing . ' The present optimum procedure for preparing copoly¬ es te rcarbona tes of the invention minimize the anhydride present in the polymer and maximizes the quantity of diacid incorporated into the polymer. A partial incorporation of the diacid not only affects the product consistency but the unreacted diacid remains in the aqueous phase at the end of the reaction as the salt and can pose problems in the later treatment of that phase. Therefore the polymerization must be carried out in a certain pH range and certain time to allow the incorporation into the polymer of the diacid but the pH must then be raised to a certain level and for a sufficient length of time during the latter stages of the polymeriz tion to enable the anhydrides to be altered to ester bonds, thereby providing the invention copolyestercarbonate which is essentially anhydride free. Generally with the passages of 1.2 equivalents of phosgene per mole of dihydric phenol and diacid , the pH of the phosgenation should be maintained at about 8 for about 50-85% of the phosgenation time period and then raised to about 11 over about a thirty second time period (small batch) for the remainder of the time period, about 15-50 percent of the time. The optimum time for increasing the pH appears to be at about 70% of the phosgenation time period. Of course, it is desirable to maximize the phosgenation rate so as to bring about a minimum reaction time which utilizes equipment most productively. The phosgenation rate can be increased substantially by introducing to the reactor, a pre made solution of the salt of the diacid, preferably the sodium salt, as opposed to the diacid itself. For example when using reaction time of 26 minutes , 18 at pH 8, 8 at pH 11 to prepare a 10 mole X dodecanedioate bisphenol-A copolyestercarbonate in a axilab facility, a copolyester¬ carbonate with non detectable level of anhydride was formed leaving 74 ppm free diacid in the aqueous phase when introducing into the reactor a solution of the disodio salt • of dodecanedioic acid. Experimentation in preparing the solution of the preferred disodio salt of the dodecanedioic acid (DDDA) indicate that smaller DDDA particle size, lower percent solids and a slight excess of sodium hydroxide ail contribute to reduced dissolution times. Coarse, flaked DDDA takes more than twice as long to dissolve than the granular material prepared by pulverization in a stainless steel Waring Blender. Below are the results. TABLE Diaci Particle NaOH/DDDA Disso1 ut ion Comment Used Size Mole ra o Time (min) DDDA Granular 2.5 >180 Slurry emu DDDA Granular 2.5 7 Clear solu DDDA Flaked' 2.5 16 Clear solu DDDA Flaked' 5.0 >180 Slurry emu Azelaic' Flaked' 2.5 17 Clear solu a . Ernerox 11 4 b. 20-40 mesh c. Flakes as large as 1/ inch in diameter i d. Flakes as large as 1/2 inch in diameter The solution addition of salt of diacid was verified in larger quantity preparation of. 9 mole % dodecanedioa te bisphenol-A copolyestercarbonate. Adding about 111 pounds of phosgene in each reaction, the rate of phosgenation was increased so as to bring down the reaction time. In each case the pH was held at 8 to 8.5 until 60 pounds of phosgene had been transferred to the reactor. The pH was then ramped to 10.5-11 over, the next five minutes and held for the remainder of the reaction time. High field NMR did not detect any anhydride in the samples. The incorpora ion of the DDDA was not seriously effected by the phosgenation rates. In the Table below pounds per hour is expressed as pph. Articles molded or extruded from this copolyester- carbonate of the invention having less than 0.5 mole percent anhydride have enhanced thermal stability. Examples of such copolyestercarbonate articles are veil known. These copolyes tercarbona es may also have Cg diacid (suberic) or C Q diacid (azelaic) present in the copolyestercarbonate , as the sole eater unit that is, the lover limit of the carbon number of the diacid incorporated is extended from C^Q to Cg with the other variables remaining the same. In Figure 2, therefore, X would have a lover limit of 6 carbon atoms. Polymers of the invention with less than about 500 ppm free diacid in the aqueous phase are readily prepared.

Claims: WHAT IS CLAIMED IS: 1. A composition comprising a copolyestercarbona e derived from a dihydric phenol, a carbonate precursor, and an aliphatic alpha omega dicarboxylic acid or ester precursor wherein the dicarboxylic acid or ester precursor has from 10 to about 20 carbon atoms , inclusive, and is present in the copolyestercarbona e in quantities of from about 2 to 30 mole percent of the dihydric phenol. 2. The composition in accordance with claim 1 wherein the dicarboxylic acid or ester precursor has from 10 to about 14 carbon atoms, inclusive. 3. The composition in accordance with claim 2 wherein the dicarboxylic acid has 10 carbon atoms. 4. The composition in accordance with claim 2 wherein the dicarboxylic acid has 12 carbon atoms. 5. The composition in accordance with claim 1 wherein the mole percent is from about 8 to 15 mole percent . 6. The composition in accordance with claim 2 wherein the mole percent is from about 8 to 15 mole percent. 7. A composition. comprising a copolyestercarbonate derived from a dihydric phenol, a carbonate precursor, and an aliphatic alpha omega dicarboxylic acid or ester precursor wherein the dicarboxylic acid or ester precursor has from 8 to about 20 carbon atoms , inclusive, and is present in the copolyestercarbonate in quantities of from about 2 to 30 mole percent of the dihydric phenol, wherein the copolyestercarbonate is endcapped with a monophenolic compound which provides the copolyestercarbonate with better notched izod impact resistance and ductility after aging than a phenol endcapped copolyestercarbonate. 8. The composition in accordance with claim 7 wherein the dicarboxylic acid or ester precursor has from 8 to about 14 carbon atoms, inclusive. 9. The composition in accordance with claim 7 wherein the mole percent is from about 8 to 15 mole percent. 10. The composition in accordance with claim 7 wherein the copolyestercarbonate is endcapped with a compound selected from the group consisting of i sooctylphenol , isonony lphenol , cumylphenol or a chromanyl compound. 11. The composition in accordance with claim 10 wherein the compound is paracumnylphenol . 12. The composition in accordance with claim 7 wherein the diacid is azelaic. 13. A method for processing a resin having similar molecular weight to a standard polycarbonate resin which comprises processing a copolyestercarbonate having repeat units of the structure wh e r e i n : R is independently selected from halogen, monovalent hydrocarbon, and monovalent hydroearbonoxy radica Is ; - R is independently selected from halogen, monova lent, hydrocarbon , and monovalent hydroearbonoxy rad icals ; W is selected from divalent hydrocarbon 0 0 0 II II il radicals, -S-, -S-S-, -0-, -S-, -S-, and -C-; II 0 n and n are independently selected from integers having a value of from 0 to 4 inclusive; b is either zero or one; X is an aliphatic group of about 6 to 18 carbon atoms , inclusive ; c is from about 2 to 30 mole percent of the total uni ts c+d ; and with less work than required for the said standard polycarbonate. 14. A composition comprising a copolyester¬ carbonate having repeating units of the structure. where in : R is independently selected from halogen, monovalent hydrocarbon, and monovalent hydroearbonoxy radicaIs ; R is independently selected from halogen, monovalent hydrocarbon, and monovalent hydroearbonoxy radicals ; W is selected from divalent hydrocarbon 0 0 0 il ii ιl radicals, -S-, -S-S-, -0-, -S-, -S-, and -C-; ιi 0 n and n are independently selected from integers having a value of from 0 to 4 inclusive; b is either zero or one; X is an aliphatic group of about 8 to 18 carbon atoms, inclusive; c is from about 2 to 30 mole percent of the total uni ts c+d . 15. An extruded article prepared from the copolyester carbonate of claim 14. 16. An article in accordance with claim 15 prepared as a sheet form. 17. An article in accordance with claim 16 prepared in film form. 18. An article in accordance with claim 16 wherein the sheet is multi walled. 19. An article in accordance with claim 14 comprising at least 90 weight percent by weight of the copolyestercarbonate of claim 14. 20. The thermoformed sheet in accordance with claim 16. 21. The thermoformed film in accordance with claim 17. -35 - 22. The composition in accordance with claim 14 wherein the polymer has less than about 0.5 mole % anhydride . 10 15 20 25 30

Inventors: FONTANA LUCA PIETRO, MILLER KENNETH FREDERICK, FONTANA, LUCA, PIETRO, MILLER, KENNETH, FREDERICK
Applicants: GEN ELECTRIC, GENERAL ELECTRIC COMPANY
Application year: 1990
Main classification: C08G63
IPC codes: C08G63