[1]Utlited States Patent Office 31451@966 3,451,966 POLYCARBONATE-CARBAMATES OF ALKYLIDENE DIPHENOLS AND DIHYDROXYDIPHENYL SULFONES James T. Gregory and Arthur B. Robertson, Akron, and 5 WiMam A. Keim, Barberton, Ohio, assignors to PPG Industries Ine.1 Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Filed Nov. 8, 1966, Ser. No. 592,731 U.S. Cl. 260-49 Int. Cl. C08g 20130 7 Claims 10 ABSTRACT OF THE DISCLOSURF, Polyearbonate-carbamate polyesters of (a) alkylidene 15 diphenols, (b) dihydroxydiphenyl sulfones, (c) carbonic acid, and (d) biscarbamate acids possess enhanced resistance to solvent stress cracking. These polyesters contain more alkylidene diphenol moieties than sulfone moieties, usually in ratios of from 3 to 15 to I and at least twice 20 as many carbonate as carba@inate groups. This invention deals with aromatic mixed polycarbonate resins. More particularly, it concerns alkylidene di- 25 phenol polycarbonate-carbamate resins and their preparation. According to this invention, polycarbonatecarbamate resins are provided which, among other things, evidence unusual and outstandin.- resistance to solvent stress crack- 30 ing. In this property, the polymers of this invention are distinguishable from older aromatic polycarbonates such as the polycarbonates of Bisphenol A (para,para'- isopropylidene diphenol) described in United States Letters Patent No. 3,028,365. 35 Mixed copolyesters of this invention include in their polymer chain moieties of (a) an alkylidene diphenol, (b) carbonic acid, (c) a biscarbamic acid, and (d) a dihydroxydiphenyl sulfone. Their general structure, therefore, can be represented as being composed of the fol- 40 lowing principal configurations: r-o-,-o O-C-0 - 1 11 II j L 0 0 45 ro-,-o o-c-oi 11 L 0 50 O-C-N-Y-N-C-01 8 8 wherein X is an alkylidene and X' is a sulfone (SO2) orpolysulfone linking radical between a pair of phenyl radicals and Y is the linking radical between a pair of iiitro- 5,5 gen atoms of a theoretical biscarbamic acid: HO-C-N-Y-N-C-OH 60 -N-Y-Nbeing the residue of a dianiine, preferably a secondary diamine, i.e., an amine having a pair of imino g)roups. In the resins of this invention, the ratio of alkylidene di- r phenol moieties to dihydroxydiphenyl sulfone moieties is Patented June 24, 1969 2 such that the alkylidene diphenol moieties are in excesg of the sulfone moieties. Thus, the ratio of alkylidene diphenol to the sulfone moieties is greater than one to one, more usually ih the more preferred resin on the order of between 3 and 12 to 1. Resins of this invention with somewhat higher ratios of alkylidene diphenol (up to 15 to 1) also are acceptable. Further, the preferred resins contain considerably more carbonate groups /O-C-O\ k @ I than carbamate groups /0-C Resins of this invention will contain a minimum of at least twice as many carbonate as carbamate goups. The more preferred resins contain carbonate groups from 5 to 25 times the frequency of the carbamate groups. One such goup of resins contains 2 to 20 carbonate groups per carbamate group. The exact arrangement of the various moieties in the linear chain of the contemplated polycarbonate-carbamate resins can be varied, depending upon the particular niethod employed in the manufacture thereof. In one such procedure, between 3 and 12 moles of an alkylidene bisphenol, notably Bisphenol A, per mole of dihydroxy diphenyl sulfone is phosgenated by the addition of phosgene to a liquid reaction medium containing the mixture of the two diphenols in a suitable organic solvent (for the product resin) such as methylene chloride or other partially chlorinated methane or ethane, water and sufficient alkali such as sodium hydroxide, usually at temperatures below or near the normal boiling point of the solvent. This phosgenation is conducted so as to provide for a bischloroformate of the diols linked together by carbonate linkages, or in other words, a low molecular weight chloroforrn@te terminated polyc@xbonate containing in its polymer @hain moieties of both the alkylidene bisphenol and dihydroxydiphenyl sulfone. Such bischloroformate prepolymer is then reacted with an appropriate diamine typified by piperazine, thereby incorporating in the polymer chain carbamate linkages and the diarnine moiety. Depending upon how the alkylidene bisphenol and dihydroxydiphenyl sulfone are subjected to phosgenation and incorporated in the prepolymer (intermediate lower molecular weight product), the relationship of these two respective moieties will vary. The dihydroxysulfone can be phosgenated initially in the absence of alkylidene bisphenol to provide a bischloroformate of the sulfone moiety or a plurality of sulf one moieties linked to one another by carbonate groups) which upon reaction with alkylidene bisphenol and additional phosgene restilts in a low molecular weight prepolymer terminated with chloroformate groups linked directly to alkylidene bisphenol moieties. Upon reaction of this prepolymer with diamine, the thermoplastic linear polymer which is provided is one having its carbamate linkages linked directly to the alkylidene bisphenol moieties with the dihydroxy diaryl sulfone moieties being spaced from the car@bamate linkages by one or more, usually a plurality, of alkylidene bis,)5 phenol moiety. Such a polymer has a characterizing structure which is illustrated by this formula: 0 1 1 F 01 -bi-O O-C-@,-Y--C-O-X- 0-8 0 Sol 0- 11 ii L 0 0
[2]3,451,966 3 wherein X is an alkylidene linking group, Y is a bridging group between a pair of amine nitrogens as hereinbefore detailed and q is a value of one or more. Altematively, a more random distribution of the dihydroxydiaryl sulfone and alkylidene diphenol carbonate 5 linkages can be achieved by phosgenating a @mixture containing both alkylidene bisphenol and dihydroxydiaryl sulfone. So provided prepolymer chloroformate has its sulfone and alkylidene diphenol moieties distributed at random. Upon reaction with the diamine, the polymer has 10 at least some dihydroxy diaryl sulfone moieties (albeit but a minor portion) of the moieties linked directly to the nitrogen (i.e., directly linked to the carbamate -roup). These more random polymers will differ struturally frorn those immediately hereinbefore described in that at least 15 some of the carbamate linkages will have the dihydroxydiaryl sulfone linked directly thereto. Under the normal conditions of phosgenation, the alkylidene bisphenol is more reactive than the dihydroxydiphenyl sulfone in the formation of carbonate and - chloro- 20 formate linkages. This coupled with the greater concentration of alkylidene bisphenol (normally present to provide for about from 3 to 12 tinies the number of its moieties compared with moieties of dihydroxydiaryl sulfone) favors products in which the alkylidene bisphen0l 25 moieties are directly linked to the carbamate group. Unless special steps are taken to accentuate those conditions which would favor the provision of linkages in which the sulfone moiety is linked to a carbamate group few such groupings are likely to be in the polymer. 30 A further variation in the configuration of polycarbollate-carbamate dihydroxydiaryl sulfone modified - polymers of the present invention is provided by a procedure wherein a bischloroformate prepolymer of alkylidene bisphenol is provided (that is, a low molecular wei.-ht bis- 35 chloroformate of a polycarbonate of the alkylidene bisphenol). Such chloroformate typically has the following structure: 4 invention have polyurethane blocks in the chain which may be represented as: Fl N-Y- -c-o-A-0-C 11 II J, L 0 0 wherein Y is a residue of a diamine, A is either a dihydroxydiphenyl sulfone or alk-ylidene bisphenol residue or both and r is a value of 2 or more, rarely above 10. Polyurethane blocks are provided by reacting a substantially equimolecular proportion of bischloroformate of the diphenol. A stoichiometric excess of either diamine or bischloroformate is employed to limit the chain length of the polyurethane segment. The resulting product is then reacted with diphenol and phosgene. Formation of the carbamate groups in the polymers of the pre$ent invention, of course, is not necessarily limited to the reaction of amine groiips (having a reactive hydrogen) with chloroformate groups but obviously can be provided by other known reactions for forming carbamate (or urethane) groups including, for example, the reaction of a bydroxy group with an isocyanate group, tbus giving rise to a urethane (carbamate) group. This route does not directly give uretbane groups which are free of hydrogens linked directly to their nitrogens. It is, therefore, unsuited for the direct preparation of the preferred polymers of the present invention in which the carbamate groups are provided from secondary diamines, or in other words, have carbamate groups in which the carbamate nitrogen is free from hydrogen atoms directly attached thereto. Such polymers are -more stable thermally than polymers in which the carbamate nitrogen is linked to a hydrogen, rendering these preferred resins especialiy suitable for tnolding applications in which the polymer is heated, for example, injection molding. . The following examples illustrate the manner in which the present invention may be practiced: 0 11-0 F ei-o O-C-0 -Xo-c-ei <D-X-C->- 8 j C> <:D- 11 L P 0 wherein p is a value usually of from 6 to 20. Upon reacEXAMPLEI tion of this bischloroformate with a stoichiometric excess of dihydroxydiphenyl sulfone (more than one, usually up Using this procedure, a series of polyester resins illusto 2 moles of sulfone per mole equivalent of bischlorotrative of the resins of this invention were prepared. forniate), an intermediate or low molecular weight polyA glass reaction flask equipped with a stitrer was mer having dihydroxydiaryl sulfone end groups can be 50 charged with 529.2 grams of aqueous sodium h'ydroxide attained. Phosgenation thereof to for-m a bis6hloroformate containing 6.725 moles of NAOH and 1700 mill iiters of and further reaction with diamine (or direct reaction with distilled water. To the solution a total of 0.4 gram of a diisocyanate when carbamate linkages of primary amines sodium dithionate was added in two equal steps followcan be tolerated) gives rise to products in which the caring whicih 6.85 grams of solid phenol were add@d. With bamate groupg are primarily attached directly to moieties 55 this liquid kept free of oxygen by nitrogen pi*ging, a of the dihydroxydiaryl sulfone, such as illustrated by the total of 2.0 moles of Bisphenol A and dihydroxydiphenyl following configurations: sulfone (in the mole ratio set forth in the table herein01 0 -c-N-Y-IN-C-FOS02- 0- -<:D-x-<@::>-o 8 8 L and/or o l f-0 so O-C FO SOI- O-Cs -<:D- -<::> llj-N-y-x-c-L-<@D<:DL o q & where X, Y and q are as before defined. after) and 1200 milliliters of methylene chloride were Yet another variation in the chain of the contemplated charged. linear thermoplastic carbonate-carbamate copolymer of With the reaction medium being stirred and maintained alkylidene bisphenols and dihydroxydiaryl sulfones is the at about 25' C. (23'-30' C.), 4.06 grams of phosgene provision therein of polyurethane blocks of either or both per minute were fed until a total of 276.1 grams of phosthese two diphenols. Thus, one group of the resins of this 75 gene had been added. A total of 0.2 mole of piperazine
[3]3,451,966 was then added while vigorously stirring the medium as an aqueous solution of 17.23 grams of piperazine in 150 milliliters of water. Cooling and control of the addition rate was practiced to avoid a violent reaction. One hour after concluding the addition of phos,- ene, 5 0.83 gram of triethylamine in 100 - milliliters of water was added to the flask. Subsequently, enough aqueous sodium hydroxide was added to complete hydrolysis of any chloroformate chlorine. The polymer is then recovered by decanting the 10 aqueous layer, washing the remaining organic layer, partially concentrating the washed solution to about 4 liters in voltime, diluting with an equal volume of hexane to effect polymer precipitation, separating and grinding the precipitated polymer, drying @under vacuum and final15 ly extrudin,-. T'hese polymers were then tested for their resistance to stress crackin.- in carbon tetrachloride and gasoline, followin.- the test iprocedure described in SPE Journal, June 1962, on pa-,es 667 to 670, in an article entitled 20 "Stress Crackin.- of Rigid Thermoplastics" by R. L. Bergen, Jr. The table lists the ratio of ingredients charged (and incoporated in the polymer) and the stress cracking values (S,,) obtained for the resin: 25 6 stress cracking, good impact stren.ath, these thermopiastic resins are effectively injection molded into products which are useful under the hood of an automobile, such as a carburetor housing. In lieu of para,para'-isopropylidene diphenol (Bisphenol A), oiher alkylidene diphenol's alone or in admixture may be employed to attain the herein co-ntemplated polymers. As a rule, the preferred diphenols are ones in which the alkylidene group is a hydrocarbon or halohydrocarbon group of up to 10 carbon atoms, more notably I to 5 carbon atoms. Aniong these rnay be mentioned the following-. (4,4'-dihydroxydiphenyl) methane 1, 1- (4,4'-dihydroxydiphenyl) cyclohexane 2,2'- methylene bis(4-methyl-6-tertiary butyl phenol) 2,2'-methylene bis(4-ethyl-6-tertiary butyl phenol) 4,4'-butylidene bis(3-methyl-6-tertiary b tyl phenol) 1,1-(4,4'-dihydroxy-3,3'- dimethyl diphenyl)cyclohexane 2,2-(2,2'-dihydroxy-4 ,4'-di-tert-butyl diphenyl)propane 3,4- (4,4'-dihydroxydiphenyl) hexane 1,1-(4,4'-dihydroxy diphenyl)-l-phenyl ethane 2,2- (4,4'- dihydroxydiphenyl) butane 2,2'- (4,4'-dihydroxydiphenyl) pentane TABLE.-POLYMER COMPOSITION (MOLE PERCENT) S t r e s s c r a c k i r i g Charged Found Sv, P.S.i. Polyraer BPA Sulfone Pip _ BPA__ Sulfone Pip CC14 Gasoline * ----------------- 85.9 5.0 9.1 90.7 1.9 7.4 460 1,800 * --- ------------- 80.0 10.0 10.0 84.1 7.1 8.8 645 2,580 c ----------------- 70.0 20.0 10.0 75.7 13.4 10.9 1,730 3,860 * ----------------- 75.0 15.0 10.0 74.5 15.7 9.8 1,900 3,600 * ----------------- 65.0 25.0 10.0 72.7 18.0 9.3 2,870 5,200 * ----------------- 65.0 25.0 10.0 69.4 20.7 9.9 14,000 4,550 1 Did not crael, but crazed between 4,000-5,000 p.s.i. BPA=para,pars@-isopropylidene diphenol; Salfone=para,paxa@- di(hydroxyphenyl)sulfone; Pip=piperazine. These values demonstrate the hi.-h degree of polymer resistance to solvent stress cracking and are strikin.-ly greater than those of carbonate-carbamate copolymers of 40 two of the three components at - comparable mole concentrations. EXAMPLE II Following @the general procedure of Example 1, a re45 action flask was charged with 182 grams of 50.5 percent aqueous NAO@H (2.3 moles), 63.6 grams (0.6 mole) of sodium carbonate, 900 milliliters of water, OA gram of sodium dithionate, 2.29 grams of phenol, 178 grams (0.78) of Bisphenol A and 600 milliliters of methylene 50 chloride. While agitating the raixture and with it at about 27' C., 104 grams @(1.10 moles) of phosgene were fed at the rate of 2.32 grams per minute. Thereafter, a solution made up of 57.5 grams (0.23 mole) dihydroxydiphenyl sulfone, 0.2 gram sodium dithionate, 84.8 grams 55 c,f sodium carbonate, 30 grams of 50 percent NAOH (0.37 mole NAOH) and enough distilled water to give a total volume of 800 milliliters was added to the reaction flask. Phosgene addition was then again commenced until an additional 30.4 grams -(0.307 mole) had been 60 added so that a total of 134.4,grams of phosgene for the whole preparation had been added. The requisite amount of piperazine (about 0.1 mole) was then added as a dilute aqueous solution and 600 milliliters of methylene chloride were also added. Small 6,5 amounts of triethylamine were added in several steps as was some sodium bydroxide. By virtue of the order in which the alkylidene bisphenol and dihydroxydiphenyl sulfone were added and reacted, this polymer will have a considarable portic@n Of 70 its sulfone moieties linked to the carbamate groups oi the polymer. Tested by the procedure specified in Example I, this polymer had ;an S, in gasoline of 3600 p.s.i. and 2160 in carbon tetrachloride. Because of their hi_Rh degree of resistance to solvent 75 3,3'- (4,4'-dihydroxydiphenyl)pentane 2,2'-(4,4'-dihydroxydiphenyl)-3-methyl butane 2,2'-(4,4'-dihydroxydiphenyl)hexane 2,2'-(4,4'-dihydroxydiphenyl)-4-methyl pentane 2,2'-(4,4'-dihydroxydiphenyl)heptane 4,4- (4,4'-dihydroxydiphenyl) heptane 2,2- (4,4'-dihydroxydiphenyl) tridecane 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane 2,2-bis(tetrachlorohydroxyphenyl)propane 2,2-bis(3- chloro-4-hydroxyphenyl)propane Dihydroxy diaryl sulfones other than 4,4'-dihydroxyIdiphen-yl sulfone (bis(para-hydroxyphenyl)sulfone) can be employed in lieu of or in admixture with that sulfone to give rise to bighly desirable polyesters. Among the dihydroxydiphenyl sulfones which as a class can be so used there may be mentioned 2,4'- dihydroxydihpenyl sulfone, 5'-chloro-2,4'-di hydroxydihpenyl sulfone, 5'- chloro2',4-dihydroxydiphenyl sulfone) 5'-chloro-2',4-di,hydroxydiphenyl sulfone, 3'-chloro-4,4'-dihydroxydiphenyl sulfone, bis(4- hydroxyphenyl(biphenol disulfone as well as other sulfones which contain further substituents on the phenyl groups, notably alkyl, alkylol, nitro and halogens such as chlorine, fluorine and bromine. Polysulfones, notably disulfones such as bis(4- hydroxyphenyl)biphenyl disulfone and the like can be used. The foregoing examples illustrate polyearbonate-carbamate-sulfone polymers which possess outstanding resistance to solvent stress cracking and, furthermore are especially resistant to both hydrolytic and thermal deco-position or deterioration. Other such linear t.hermoplastic polycarbonate-carbamate-sulfone products are provided by using in lieu of piperazine described in the foregoing examples other diamines, for example, 2-niethyl piperazine, 2,5-dimetbyl piperazine,- 2,6-dimethyl piperazine and other lower alkyl substittited piperazines. Other
[4]3,451,966 7 8 diamines containing a pair of imino groups that is, amino Other diphenolics which may be used include comnitrogens having one hydrogen linked directly thereto, pounds such as: llo-<:D-SO2- <@D-X-<::::>-s ol-c@>-Oi-l 110-<D-SO2-<::@>-O -<@D-X<D-O-<@@>- SO2-<:::>-Oll including diamines which conform with the structure of the following formula: 15 R RI wherein X is typically a hydrocarbon radical or sub- 20 stituted dirvalent hydrocarbon radical which usually contains up to 8 carbon atoms (and rarely rnore than 15) and R and R' are substituents other than hydrogen, more usually lower alkyl groups of I to 6 carbons, such as methyl, ethyl, isopropyl or butyl alkyl groups. Many of 2,5 these secondary diamines may be prepared, as the literature rceognizes, by reaction of an N-alkyl aniline such as N-methyl aniline with an aldehyde such as formaldehyde, butylaldehyde and like aldehydes containing up to 8 or more carbon atoms or a ketone such as acetone, methyl 30 ethyl ketone, diethyl ketone or like ketones - including cyclic 11 ketones such as cyclohexanone and bridged cyclic ketones containing up to 8 or more carbon atoms. P . rimary diamines may be used to produce thermopla5tic resins within the contemplation of the present in- 35 vention. However, the thermal stability of these resiiis is significantly less than those derived from - secondary amiire , s such as piperazine. 'rhus, the preferred mixed polycarbonate-carbamate esters of the pr,-sent - invention caiinot be prepared directly by reaction of a diisocyanate, 40 for exarliple,,with a bisphenol because such reaction would lead directly to a carbamate group bearing a hydrogen atom on the nitrogen of the carbamate. It is, of course, poss,ible to treat such carbamate groups to replace the hydrpgen. Also these hydrogen bearin.@ carbamate nitro- 45 gen . s may be cross-linked as by -urea linkages (reaction with isocyanate groups) to give less thermoplastic even ther I moset or highly three dimensional products. Thus, car@,qmate groups derived from primary diamines such as the aliphatic diamines t@ypified by methylene diamine, .50 f hexamethylene diamine, propylene diamine, tetramethyl ene d . iamine, 4,4'-diamino-dicyclohexamethane, . diaminobenz'ophenone, N-phenylene diamine, or tho-toluylene, meta-tolyjene and the like can be present. @lf present in small enough proportion to carbamates of - secondary 55 am . ines the polymers will have sufficient thermal - stability. Moreover, the polycarbonate-carbamate-sulfone type resins of this invention need not be Testricted solely to preparation from an alkylidene bisphenol, a diamine, a carbonic acid precursor such as phosgene or chlorofor- 60 mate and a dihydroxy diaryl sul ne. may contain still other dihydric components and other dibasic acid components. Thus, a portion of the alkylidene bisphenol may be replaced by dihydric alcohols of the glycol character such as ethylene glycol, diethylene glycol, 1,3- pro- 65 pa@ie glycol, 1,4-butane glycol, resorcinot, hydroquinone, thiodiglycol, phthalyl alcohol, dihydroxydiphenyl, dihydroxydiphenyl ether and the like. Additionally, a portion of the dibasic acid moieties provided by the carbonic acid precursor or biscarbamic acid may be replaced 70 by other diflinctional acidic reagents, most notably dibas.ic acids such as maleic, phthalic, terephthalic, isophthalic and the like. wherein X is an alkylidene group such as propylidene. In lieu of the methods described for preparing these resins, other recognized techniques for forming carbonate linkages from phenolic hydroxyls and phosgene can be -atilized. For example, the bisphenols (including sulfones) can be phosgenated in an anhydrous medium to form the prepolymer chloroformate carbonate for reaction with diamine. Diphenyl carbonate and lower alkyl esters of diphenot car@bonates can by heating and interesterification be reacted to also give rise to polycarbonate prepolymers which can be phos,-enated and reacted with diamines. While the present invention has 'been described with reference to specific embodiments, it is not intended that it be construed as limited to such embodirnents and details thereof except and to the extent that these such details are set forth in the appended claims. We
