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4 i/, fte- IPO T1CHNKAL DOCUMINT MtKARCH AND DBVCLOPMENT REPORT Improved Estol B/1,4 BuUnodlol Blond Thormol Stability l. Effect of Stabiliser* (Chelator*) and Alternative Polyeeterlflcatlon Catalyet (Stannous Chloride). by K. Dlnbergs ^ |______ 7745-74, 75 ^ -___ Eetane ____ July 13. 1976 - fir -fr---------------------- C. S. Schollenberger Dtstrlhotloo Cleveland R. D. Scott-R. A. Krueger B. hi. C. Zwlcker-M. E. Roha K. Greene F. E. Krause J. L. Nelson-A. W. Clements E. J. Sehm-J. C. Healy-r. J. Donat* E.B. Osborne-J.r.lialane* O.S.W--r r.T.Nm D. D. IHtmor-R. L.Markley* ALTC CTr/latemntlsnsl-4 R. R. Bluer R. M. Kreager-A. L. Schelts* J. A. TePas - B. K. Mlkofalvy* R. J. Meyer Breckavllle R. J. Fawcett* G. E. Thompson* C. H. Lufter* D. E. Ley* R. K. Schlataer* C. S. Schollenberger L. E. Hewitt RAD riles (Project 7741-761-2 Akron J.H. Powell, Jr. J1S 3 Technical Files-2 ALGCP H. E. Gaylor "Summary Only tm 41982 22383001 BFG20408 ri TABLE Of CONTTNTS Project 7745-74,75 July 13, 1976 Summary and Conclusion*............................................................................ Objective ............................... ............... ............................. Recommendations ......................................................................... Introduction ........................................ ..................................... Experimental Part ........................................................................... 1 Materials ...................... ..................................................... Procedure ........................................................................ 1. Heat Aging of Blends.............................................................................. 2. Preparation of Estanc 5701 ........................................................ 111 Test Methods ............................................................................ 1. 1,4-Butaaediol (1,4-BDO) Determination la Estol B/ 1,4-BDO Blends by Cas Chromatography (GC).................. 2. Molecular Weight Distribution (MWD) of Estol 7/1,4- BDO Blends by Gel Permeation Chromatography (GPC).. 3. Stress-StrainProperties.................................................... 4. Aging Conditions .......... ..................................................... .. Discussion of Results ................................................................................... I Tatra (2-Ethyl Hexyl) Tltanate (TEHT)-Containing Blends ... 1. Factors that Affect Blend Stability on Heat Aging .............. A. Temperature Effect on Blend 1,4-BDO Content (by GC).. B. 1,4-Butanedlol Cone. Effect on Blend MWD (by GPC) ,. C. Catalyst (TEHT) Level Effect on Blend MWD (by GPC) .. 2. Effective Stabilisers ...................... ..................................................... A. Quinollnol Effect on Blend MWD (by CPC) and 1.4-BDO Content (by GC) ......................................................... B. Acetyl Acetone Effect on Blend MWD (by GPC) and 1.4- BDO Content (byGC) ........................................................ C. N,N,N|N' -Tetra-n-butyl ethylene dlaminetetraacetate (TBEDTA) Effect on 1,4- BDO Content (by GC)......... 3. Other Compounds that have been Evaluated as Estol B- 1.4 BDO Blend Alcoholysis Stabilisers.................................... 4. Effect of OainolLnol and Acetyl Acetone on Blend Color Stability Daring Ambient Storage 5. Effect of Quinollnol and Acetyl Acetone on Estane 5701 .. A. Polymerisation ............................................................................... B. Original Properties and Environmental Resistance.,,,,, II Stannous Chloride-Containing Estol B/1.4 BDO Blend Alcoholysis Stability ................................................ 1. Heat Stability of Blends Made with Washed Estol B,,,., A. Changes In Blend Molecular Weight Distribution (GPCV . B. Changes la Blend1,4-Butanedlol Content................................ 1 3 3 4 5 5 8 8 8 9 9 9 10 10 10 10 10 11 11 13 21 22 23 23 23 25 31 31 33 10 13 19 31 S.F.OOOOSKH BFG20409 T Project 7745-74,75 July 13, 1976 TABLE Of CONTENTS Pate Hu' Stability of Bland* Mad# with Unwaahad Estol B .. Changes la Bland Molecular Weight Distribution (GPC) and la Bland 1,4-Botanadlol Content (GC).......................... Tha Special Caaa of Bland It Conversion of 1,4 BDO to Tetrahydrofuraa (THF) by Molecular Slava* ................... Effect of Stannous Chloride on E*tana 5701 ..................... Polymarlaation ............................................................................ Polymer Original Proparti#* and Environmental Resistance ............................................................................ (1) Solution of the Oven Aging "Brown Speck" Myatary. References Acknowledgme nts 45 ;2383003 W a.r. BFG20410 T 1- Project No. 7745-74, 75 July 13. 1976 Improved Estol B/1,4 Butanedlol Blond Thermal Stability 1, Effect of Stabilisers (Chelators) and Alternative Polyesterification Catalyst (Stannous Chloride) SUMMARY 6 CONCLUSIONS Estol B [poly(tetramethylene adlpate)glycol] and 1.4 BE1' >(1,4-butanedlol) are blended la precise molar ratios for nee In Eetane manufacture. The ratio of these two components, as well as the molecular weight of the Estol B, de termines Eataae composition, properties, and performance and Is, therefore, critical. Over a period of time some serious problems were encountered In the performance of certain commercial Estanes, Including polymers sold for adhesive applications (5713), and more recently, automotive Injection molding applications (58130). The above problems were felt to be related to the reduction of Estol B molecular weight In the blende by thermally induced alcoholysis of the poly ester via the 1,4 BDO chain extender component during the makeup, storage, and use of the blende in the Eetane manufacturing process. Such alcoholysis reduces the molecular weight of the Estol B (polyester) component, and simultaneously consumes free 1.4 BOO by incorporating It In the shortened polyester chains. This change assures that the contemplated Estane product will not be obtained on subsequent Estane polymerisation with MDI (dlphenylmethane-p, p'-diisocyanate). The growing seriousness of the blend alcoholysis problem led to a major effort to find a satisfactory solution. Research joined Production and Development In this effort In March. 1974. My study o# the problem, using gel permeation chromatography (CPC) and gas chromatography (OC) as tools, has shown that the thermally Induced alcoholysis ei Eetel B-1,4 BDO blends Is strongly accelerated by the titanium, residual from the Production Estol B polyesterlflcatlon catalyst, tetra (2ethylhexyl) tltanate (TEHT). And that this alcoholysis Increases with Increas ing blend temperature. 1,4 BDO concentration, and TEHT concentration. .r.QOOMKH BFG20411 T -2- Proj.ct No. 7745-74. 75 July 15. 1576 la the court* of my ttudlei I investigated two routes to more stable Estol B/1,4 BDO blends. Those were: (I) the use of small amounts of che lating agents for titanium In blends containing TEHT catalysed Estol B; (21 the use of an Estol B polyesterl/lcatlon catalyst alternative to TEHT which does not accelerate polyester alcoholysis In the blend. Both approaches have proved to be fruitful. Chelators - Effsctlve and adequate chelators found Include quinollnol (Q) and acetylacetone (AcAc). However, Q has a persistent medicinal odor and AcAc has some odor. Ethylenedlamlne tetraacetlc acid (EDTA), which Is odor* less, should be an effective chelator for titanium but It Is ineffective, most likely due to Its Insolubility In the blend. Moreover. It contains hydrolysis accelerating carboxyl groupe. So I prepared N, N. N'N'-tetra-n-butyl ethylene dlamlne tetra acetate (TB EDTA) which proves to be a colorless, essentially odorless, soluble, high boiling liquid. Moreover, tests show that even at low levels TB EDTA la a good, possibly adequate, stabiliser of ' stol B-1,4 BDO blends against thermally Induced. TEHT-accelerated alcoholysis, presumably by Its unexpectedly good ability to chelate titanium. The above chelators are quite effsctlve In stabilising TEHT-containlng blends at -0. 2 parts per hundred of blend (wt.). And neither Q nor AcAc at these levels adversely affect the measured original properties/environmental stability of the Estane tested (5701). The effect of TB EDTA on Estane environ mental stability has not been determined. Alternative Catalysts - 1 found that Estol B/1,4 BDO blends made from Estol B whose formation was accelerated by the alternative polyeeterlflcation catalyst, stannous chloride dihydrate (SnCV 2H, O), show remarkable and ade quate Inherent stability to alcoholysis at typical temperatures encountered In blend makeup, storage, and use. And that at (effective) levels of-65 ppm. SnCIa* H,0 catalyst/residue does not significantly affect the measured original properties/environmental resistance of Estane 5701, with the exception that long term heat aging (140*C. /air) and stress-strain properties are slightly poorer. In the course of the present investigation I made two other interesting and worthwhile discoveries, namely: (1) treatment of 1.4 BDO with 4A molecular slaves at ~90*C. produces tstrshydrofuran, apparently by a cyclodehydration reaction, in good yloldt (2) contamination of Estane with Imperceptible PVC dust by routine mltl-mas slag the Estane on our "clean" plastics mill has, for K> some time, introduced invisible PVC particles Into the Estane. These particles become brown specks when the Estane Is host aged (140*C.) In air which in- W tenslfy with aging time, apparently evolving an agent (HC1?) which diffuses w radially Into the surrounding Estane matrix, turning it yellow and eventually brown. ;Ss BFG20412 T Project Ho. 7745-74, 73 July 13, 1474 The foregoing results of my investigation, which were confirmed by ALTC studies, allowed a choice - chelation or alternative Estol catalyst - to be made In solving the blend stability problem. Supported by the valuable guidance of Dr. L. E. Hewitt's thermal analysis studies and ALTC molding trials and property evaluations, the latter option was selected to meet the urgent Estane 58130 Injection molding polymer problem. It was promptly applied by Production In timely rescue of that promising automotive business. OBJECTIVES The objectives of this study were to determine the basic cause of Estol B/ 1,4 BDO blend Inetablllty and then provide means of overcoming the problem that would be acceptable and adaptable to our Estane manufacturing process. RECOMMENDATIONS In order to produce Estol B-1,4 BDO blends of au^quate thermal stability for use In manufacturing Estane thermoplastic polyurethanes, I recommend that minimum effective levels of stannous chloride dlhydrate be substituted for tetra (2-ethylhexyl) tltanate (TEHT) as Estol B polyesterlflcatlon catalyst. Or In the event that the use of TEHT as Estol B polyesterlflcatlon catalyst be con tinued, I recommend that one of the following metal chelators be considered as an additive to blends which contain TEHT-catalysed Estol B In order to stabil ise the blends against thermally Induced polyester alcoholysis: acetyl acetone (AcAc); N.N.N'.N'-tetra-n-butyl ethylenedlamlnetetraacetate (TB EDTA): or 8-hydroxyquinoline (qulnollnol, Q), if the persistent medicinal odor of Q can bo tolerated. Should Interest warrant, the preparation of tetrahydrofuran bv the cvclodehydration of 1.4-butanedlol via molecular sieves should be further studied. The adverse effect of PVC on Estane color when such combinations are heated should be borne la mind In deciding their applications. s.r. BFG20413 T T ! ouoeQZzz '^SSsr: -4- Projeet No. 7745-74, 75 July 13, 1976 INTRODUCTION To product tow acid aumbtr Eatol B [poly (tetramethylene adipate)] glycol Eatano Production haa catalyaod tho polyesterlflcatlon raactlon with tatra (2-ethylhexyl)tltanate (TEHT) ualng lavala ranging from 15 to about 10 ppm. Thla Eatol B la than blandod with varloua amounta of 1,4-butanadlol and atorad for about 10-14 daya (but occaalonally up to ona month) at alavatad tamparaturaa awaiting uaa In tho Eatano manufacturing procoaa. Storago tomporaturo deponda on tho typo of blond uaod. It can rango from 140*F. (60'C.) to 200*F. (93*C.), and for high molecular weight Eatol B (>3000 MW) It could exceed 200*F. Earlier atudlea ahowed that Eatol B-1,4 BDO blenda can undergo an alcoholyala (deatruettve eater Interchange) reaction when heated at elevated temperatureo (1). Thla reaction reducee the molecular weight of the polyeater (Eatol B) component and tho amount of the free 1,4 BDO component aa It Incorporatea the latter In the ahortened polyeater chalna. More recent work by Jim Haehn (ALTC) (2) haa ahown that the Eatol B-1,4 BDO blenda prepared for uae In Eatano manufacture exhibit thla Instability at temperatures encountered in their makeup, storage, and uae in the Eatano manufacturing procoaa. These undesirable changes In the blenda on atorage at elevated temperatures have a serious and often adverse effect on the properties of the Estane polymers pre pared from them. In the case of Eatol B/1,4 BDO blend alcoholysis the 1,4-BDOcleaves the polyester chain and combines with the broken chain fragment that carries the carboxy fragment, thua reducing the average molecular weight of the poly ester component and consuming free 1,4 BDO. But "blend molecular weight" remains unchanged. This reaction Is Illustrated In Equation I. -(Cm,-COb(CHW-9T^(C^kCOb(CHU _ H-6(01^011 I *4 (Equation I) -(CHUC<VCl^h-OH 4 CO(CH,)*CO,(C^U CHCH.WOH la my earlier study (1) I found that this alcoholysis reaction Is accelerated by heat, high 1,4-BDO concentration, and catalysts. I also found the rate of alcoholysis of uncatalysod blends to be quite alow at ~100*C. But at 140*C. noticeable alcoholysis occurred, and at 170*C. the alcoholysis rate was fairly rapid! " I.M BFG20414 T T" 1 2383007 -5. Project No. 7745-74. 75 July 13, 1976 la addition. I found that undor the same 'nrHItlom an uncatalysad bland coataialaf 2 molaa of 1,4- BDO underwent notlcaabla alcoholyaia, wharaaa a bland containing only 1 mola of 1.4-BDO did not. Furthermore, I found that tha phanollc antioxidant. CAO- l[2.6-dltartlary butyl-p-cresol] la a catalyat for tha alcoholyaia raactlon In Eatol B- 1,4-BDO blanda. My aarllar ra port (I) concludaa that uncatalysad Eatol B (M.W. 1000) 1,4-BDO blanda containing 0.3 or 1.0 mola of 1,4-BDO cannot ba haatad for >24 hours at about 100*C., and blanda containing 2.0 molaa 1,4-BDO cannot be haatad at>50*C. without maaaurabla alcoholyaia of tha Eatol B. Tha objactlvaa of tha work daocrlbed In my praaant raport ware to pinpoint tha basic cauaa of tha savara alcoholysis problem currently encountered In Eatol B/1.4-BDO blanda and to datarmlna how to provide Production with a route to more alcoholyaia-atable blanda for Estane manufacture. I have found that this can ba accomplished by using an effective atablllser (metal chelator) In the blanda or by the uaa of an alternative Eatol B poly- iterlficatlon catalyat that does not subsequently catalyse bland alcoholyaia and does not significantly affect the environmental resistance of the derived Estane (3A). The effective ness of the stabilisers and the alternate catalyst was confirmed at Avon Lake (3B. C. D. E, F. G). Experimental Part I Materials 1. Estol B fpoly (tetramethvlene adipate)slvcoil. The following Estol B lots were used In this study: (A) 7745-74-5. Estol 5711. Tank #5, BLD #608 and #609, Avon Lake anal. OH# 54.58, Acid #0.31, Mol.Wt. 2032. BrecksvlUe anal. OH# 54.2, Acid# 0.4. Mol.Wt. 2040. Contains 3.5 ppm tatra (2-ethyl hexyl) tltanate according to X-ray fluorescence analysis. (B) 2074-70-1150B, OH# 56.7. Acid #0. 1. Mol. Wt. 1972 made with 67 ppm SnCIa 23^0 calculated at the point of addition (after the removal of water but before transesterlftcatlon), water washed. Calculated amount of tin In the polyester. 49 ppm. Calculated amount of tin In the blend with 2. 00 moles 1,4-butanediet, 45 ppm. Tin found by X-ray fluorescence in the blend made from water extracted Estol B, 42 ppm (93% of the calculated amount). (C) 2074-72-2468. OH# 50.7. Acid # 0.2. Mol.Wt. 2192. Made with 75 ppm SnC^ 21^0 calculated at the point of addition (after re moval of ureter but before transesterlflcatlon). Water washed. M.OOOOOKH BFG20415 T tr 'war -6- Project No. 7745-74. 75 July 13, 1476 (D) 7745*75-72. OH# 68.4, Acid *0. ?. V-'. Wt. 1631. Made with 65 ppm SnCl, 2H,0 calculated on the weight of the polyester after the removal of water but before transeatertflcatlon. Not water waehed. (El 5740-73*231, OH# 94.4. Acid *0.2. Mol. Wt. 1184. Made with SnCle 2H,0 catalyst; amount at the point of addition (after the removal of water but before transesterlflcatlon). 75 ppm. Amount calculated on the final polyester, 98 ppm. Water washed. Contains 199 ppm water. (F) 7742-75-181, OHI 131.2, Acid #0.5, Mol. Wt. 849. Made at Avon Lake with 10 ppm TEHT catalyst, not water washed, con tains 1.95% free 1.4-butanedlol. background molecular weight 1020, contains 284 ppm water. (G1 5740-73-335, OH# 113.0, Acid #0. 3. Mol. Wt 988. Made with 76 ppm stannous chloride dlhydrate catalyst at the point of addition (after tho removal of water but before transesterlflcatlon). Theoretical amount of tin In the final polyester, 52 ppm. 2. 1.4-Butanedlol (A) 7745-74-5. Production material obtained from Avon Lake. Contains 2461 ppm water. (B) 7741-74-410, anhydrous, Akron Chemical Company (Antara General Aniline and Film Co.) It was purified by vacuum distilla tion. b.p. 122-126*C/8-9 mm. contains 116 ppm water. (C) 7741-74-23, anhydrous. Akron Chemical Company (Antara General Aniline and Film Co.). It was purified by vacuum distill ation, b.p. 118-123*C. at 8-10 mm. contains 92 ppm water. (O) 7742-75-189. Received from Avon Lake. BASF, contains 1967 ppm water. 3. Estol B/1.4-BPO Blend ALOCPI855, Brecksvllle I7745-76-173A, M.W. 545, A.N. 0.6. 311 ppm water, was made with 10 ppm of TEHT catalyst but according to analysis by X-ray fluorescence contains 6. 7 ppm TEHT. BFG20416 T 22383009 -7- Project No. 7745-74, 75 July 13. 1976 4. MDi (o. o'-Dlohonvlmothano dUsocvsnato) (A) 5740-73-549, Mobay Multrathano M, flakod. 99.2% port, 8 ppm hydrolysablo chloride. u used without purification but corroctod for purity. (B) 7742-75-182, Upjohn, 99. 3% puro, 28 ppm hydrolysablo chlorldo, was us ad without purification but corroctod for purity. (C) 7741-74-278A, Mobay Multrathano M, flakod. 99. 4% puro. 8 ppm hydrolysablo chlorldo, was usod without purification but corroctod for purity. (D) 5740-73-530. Mobay Multrathano M, flakod. 99.6% puro. 6 ppm hydrolysablo chlorldo was usod without purification but corroctod for purity. (E) 7741-74-411, Mobay Multrathano M, flakod, 9\2% pars, 12 ppm hydrolysablo chlorldo, was usod without purification but corroctod for purity. (F) 7745-76- 173C, Upjohn, 99.3% puro. 6 ppm hydrolysablo chlorldo. 5. Totra (2-othyl hexyl) tltanato (TEHT) obtained from Avon Lako, manufactured by tho Stauffer Chemical Co. 6. Stannous Chloride Dthydrate, BfcA, General Chemical Division, Alliad Chemical li Dye Corp., Code 2341. 7. 8-Qulnolinol (8-Hydroxyqulnollne), Fisher Scientific Company. 0-261, 77885. Lot 723347. 8. Acetyl Acetone (2,4-Pentanedlone), Fisher Scientific Company. A-25. Lot 705384. 9. EDTA (Ethylonodlamlno totra acetic acid), Tetrlne acid, Glyco Products. 10. TBEOTA (IV. N.N'.N'-totra-n-butyl othylonodlaminotetraacotato) pre pared in our laboratory (7745-75-148). Acid #: original 0.8, after 1 year's storage 7.6. 11. Taaain (Taaalc Add), Fisher Scientific Company. A- 308. j 12. 4,4.4-Triflooro- l-(2-thlenyl)-1,3-butanedlono. Eastman 7260. 2383010 | j S.F.< BFG20417 T  8- Project No. 7745-74, 75 July 13, 1976 13. 2, 2'-Blpyrldlne, C. Frtdrlck Smi'> ir.. Co., Columbus. Ohio. 14. 1. 2-Dlmethoxyethane. Eastman 1088. 15. Inhibitor NPH (ammonium salt of N-nltrosophsnyl hyd rosy lamina t. Malllnckrodt Chsmlcal Works. II Procedure 1. Hsat Alna of Blands Tho Estol B was moltad and haatad to about 50-70*C, than It was blended with tha required amount of 1,4-butanadiol, and If daslred tha calculatad amount of tltanata catalyst was addad. Than 150g of tha bland was poured Into savaral 8 os. narrow mouth scraw cap bottlss. some of which contalnad various amounts of stablllssrs. Tha stabilisers ware dissolved In the bland by shaking, rolling, and occasional heating to temperatures not ex ceeding 70*C. Most of tha stabilisers dissolved vary rapidly, some dissolved only partially, but In any case tha attempts to dissolve and mix the stabilisers with the bland did not exceed one hour. After tha stabilisers had dissolved In the blend, the original sample was taken by pouring about 20g of the blend Into a 1 os. jar. The bottles con taining the blends were then placed In an oven of 93* or at 100'C. and aged for 4 weeks. Samples for analyses were poured from these bottles after each week of aging. During the aging period the caps of the bottles were closed; there was no pressure In the bottles. 2. Preparation of Estsne 5701 A. In Glass Beaker Estane 5701 samples with or without additives or catalyst were prepared by the random melt polymerisation technique. 150g of predried Estol B was weighed out In a 400 ml beaker. A 1-7/8" diameter stainless steel propeller type stirrer was inserted In the Estol B and the beaker was placed on hot plate. With moderate stirring the temperature of the Estal B Is raised to 160*C; during this time the additives or catalyst are added. At 160*C. the 1,4 BDO Is added from a 20 ml hypodermic syringe. This lowers the temperature of the blend In the beaker to about 150*C. Then, within one minute after the addition of 1,4-butanedlol. melted MDI at 140*C. is added from a tared 150 ml beaker. The stirring speed Is gradually increased and the reac- - tlon mixture Is stirred. If possible, for 2 min. In polymerisations containing j catalyst, stirring time was reduced to about one-half minute due to the rapid ^ thickening of the polymerisation mixture. / s.r. BFG20418 T T' -9- Project No. 7745-74. 75 July 13. 1976 B. In the Brabender Plastlcordsr Reactor (BPR) - To determine the effect of additives on the polymertaatlon rate, the polymerlaationa were carried out in the BPR. The apparatus and the polymerisation procedure have been described In an earlier raport (4). Ill Teat Methods 1. 1.4-Butanedlol Determination in Estol B/l, 4-Butanedlol Blends by Gas Chromatoeranhv The gas chromatographic determinations of 1,4-butanedlol were carried out by Umars Sockla (D/8510) us inf the Hewlett-Packard 5750 gas chromatograph equipped with thermal conductivity detector. The 1/8" x 2' column contained 10% FFAP on Chromosorb W, 60/80 mesh. Column temp. 130*C. Isothermal, detector temp. 280'C, Injection port temp. 260*C. 30 cc/min. helium flow. To l-2g of the sample 0. lg of ethylene glycol was added as Internal standard, and 10 ml of acetone. The response factor was calculated from a standard aolutlon containing 0. lg of ethylene glycol and 0. lg of 1,4-butanedlol dissolved In 10 ml of acetone. All Injections were 5. Opl. 2. GPC Analysis of Estol B/l,4-Butanodlol Blends GPC data were obtained by D. J. Harmon (D/8510) with a gel permea tion chromatograph. Model 100 (Waters Associates) which had been converted at Brecksvllle to be equivalent to Model 200. The determinations were made at 40*C. dissolving 40 mg o* the blend In 20 ml THF. The solutions were filtered through a syringe filter before In jection Into the Instrument. The syringe filter - Versapor 6429 made by Gelman has a pore else of 0.90fi, Is 13 mm dla., and about 20 mils thick. It Is emphasised that the term and numerical values of "blend Mw" (weight average molecular weight) frequently presented In this report are not actually molecular weight values but represent the average molecular else In Angstrom units of the various Estol B/1.4-BDO blends which, of course, contain considerable free 1,4-BDO. And any changes in this Rv, although due to changes in polyester molecular weight (since Rv Is primarily affected by the higher molecular weight species of the bland) really represent changes In theTT* (average molecular slse) of the blend. However, by Inspecting the actual GPC curves, which are also pre sented in this rsport, one can readily see the constancy or changes in the molecular weight distribution of the polyester component. BFG20419 ZTQ8ZZ -10- Project No. 7745-74, 75 July 13, 1976 3, Stress-Strain Proportion For *t rasa-at rain taata 6 x 6 x 0.075" or 6 x 6 x 0.025" sheets of the polymers ware compression molded for 5 minutes at 180*C. between sheets of Teflon-coated aluminum foil. The tests were run on the Instron Tester (equipped with a pogo) on three 1/8" dumbbells at an elongation rate of 20"/min. All of the samples were conditioned for 24 hrs. at 25*C. and 50% R. H. prior to test. 4. Aging Conditions ^ For oven aging 0.075" thick 1/8" dumbbells were aged In a 140'C. forced air oven flat on Teflon. Hydrolysis resistance was determined by immersing 0.025" thick 1/8" dumbbells In 70*C. water. After removal from water, the samples were desiccated for 24 hours. Dry Carbon arc Weatherometer aging was carried out on 0.025" thick 1/8" dumbbells. All aged samples were conditioned for 24 hours at 25*C. and 50% R.H. before testing. Discussion of Results I Tetra (2-Ethyl Hexyl) Tltanats (TEHT)-Contalnlng Blends 1. Factors that Affect Blend Stability on Heat Alni A. Temperature Effect on Blend 1,4 Butanedlol Content (by Gas Chromatography) Eetol B/1.4-BDO blend aging experiments at Avon Lake carried out by J. Holloway (3C) have shown that the alcoholysis reaction of the poly ester Is reduced considerably by reducing the blend storage temperature from 93*C. to 70*C. An Eetol 5711 blend containing 16% 1,4-BDO and 3.5 ppm tttanate catalyst has retained 94% of Its original 1,4-BDO content after 4 weeks at 70*C. bet only 64% of the original 1,4-BDO content after 4 weeks at 93 *C. Increasing the aging temperature from 93*C. to 100*C. had no significant effect on the alcoholysis reaction. E T 0 S 8 ZZ -11- Project No. 7745-74. 75 July 13. 1976 B. 1,4-Butanedlol Concentration Ktint on Bland Molecular Weight Distribution (by Gel Permeation Chromatoiraphy) Another factor that affecta the alcoholyele of tho polyester la the amount of glycol present In the blend, and I found that the alcoholysis increases with increasing glycol concentration. Tor example, a blend made from Estol B. M. W. 2032, containing 0.6 moles of added free 1,4-BDO and 22 ppm of TEHT was aged for 4 weeks at 93*C. During this period blend decreased from 169. 8ito 143. &JL a 15% drop. Another blend made from the same polyester, but containing 2.0 moles of added free 1,4-BDO and 19 ppm TEHT catalyst, decreased In from 158.51 to 104.61 (a 34% drop) during the same heating period. Full, normalised CPC curves for the above two blends, before and after heat aging, are shown In Figure 1 (AfcB). The mc'scular weight parameter In these CPC curvee Is expressed In the abscissa as log Angstrom length of fully extended polymer chains. We can see that the polyester In (B) (blend contains 2.0 moles of 1,4-BDO) has undergone greater changes on heat aging than the polyester In (A) (blend contains only 0.60 moles of 1,4-BDO). One change that we observe on heat aging Is the shift of the major peak to lower molecular weight, with an increase in intensity which must mean that a narrower molecular weight range of reduced polyester chains has re sulted. We also see an increase in peaks 2 and 3 counting from the right. These peaks represent lower molecular weight polyester ollgomere. The last peak counting from the right is 1,4-BDO. We can see that the 1.4-BDO peak is greater in (B) than in (A), as expected. On heat aging, the 1,4-BDO peak for both blends decreases Indicating that It is con sumed by the alcoholysis reaction (Equation 1). C. Catalyst (TEHT) Level - Effect on Blend Molecular Weight Distribution (bv Gel Permeation Chromatoiraphy) 1 also found that the level of TEHT catalyst has a measurable effect on the extent of tho alcoholysis reaction. The date on the catalyst level were obtained on a blend containing only 0.60 moles of added 1.4-BDO and. therefore, the changes on bent aging were relatively small. But still, an effect can be seen. An Estol B, M.W. 2031 blended with 0.60 mole 1.4-BDO and containing 3,5 ppm of TEHT catalyst decreased In Mw from 124.4k to 115. 9l (7*) after 4 weeks at 93*C. But the same blend containing 22 ppm of TEHT -12- Figurt I. EFFECT of 1,4-BOO CONCENTRATION on tht ALCOHOLYSIS of ESTOL B/ 1,4-BOO BLENOS on 4 WEEKS/93*C AGING. CHANGES in MWO. (A) (B) DIFFERENTIAL WEIGHT PERCENT S T o e a e zj; 0 2 30 I 23 LOG ANGSTROM LENGTH OF FULLY EXTENOEO CHAIN (A) OSO M* L4-S00 ftt IjOO Md ESTOL (*. 2031), (2*7706-74-10-1). TENT CATALYST m 100 mm 1,4-100 ftt LOO mM ESTOL S (MW. 2091), IS ^ TEMT CATALYST (CWPL 7749-74-10-8). -------------ORHWAL MWO ------------MWO fMr 4 WEEKS t OTC * tmi w Mm4 (to itoM mi ftoqi). BFG20422 - 13- Projsct No. 7745-74, 75 July 13. 1976 ca'alyst decreased In Mw from 128. 7^ to 111.21 (148i) after the me exposure. Normalised CPC graphs for both blends before and after aging are shown In Figure 2 (AlaB). The data show that the major peak in (B) (blend contains 22 ppm TEHT) has shifted more to the lower molecular weight range than (A) (blend contains only 3. 5 ppm TEHT catalystl. 2. Effective Stabilisers Since It has been found that the presence of TEHT catalyzes the aUoholysis of the polyester by the free 1,4-BDO In the blend, our approach In finding a stabiliser was to seek one that would chelate the titanium in the blend and thus render It Inactive. We have examined a number of potential chelators for this purpose and have found that some of them are effective blend stabiliz ers. Their effectiveness will now be described ana discussed. A. Qulnollnol Effect on Blend MWD (by CPC) and 1,4-BDO Content (by GPC) Qulnollnol (8-hydroxy quinoline) was found to be the most effective of all of the stabilisers investigated In this study. Aging data for blends made from Estol B (M. W. 2032) with 0.60 moles of 1.4-BDO are shown in Table I. TABLE I Changes in MWD Determined by GPC In Estol B (M. W. 2032) /0.60 mole 1,4-BDO Blend Containing Qulnollnol Stabilizer on Heat Aging at 93*C. 74 (ppm) lino*. <m Original After 24 hrs. flw, A 72 hrs. 1 wk. 2 wks. 4 wks. 5-1 3.5 0 124 . 118 (95) 118 (95) 117 (94) 116 (94) 5-3 1.5 0.04 128 124 (97) 129 (1001 128 (100) 125 (97) 128 (100) 5-4 22 0 129 125 07) 127 08) 126 (97) 117 <<*1> 111 (86) 5-6 18-1 22 22 0.04 0 130 170 126 (07) 127 071 131 >100) 117 O0' 121 < 03' 144 <85* 18-2 22 0.4 164 166 (rf 22 9.8 lo8 Numbers in parentheses indicate percent retention of original value (Mw). Table I data show that qulnollnol at the 0.04*% level offers complete stability to the blend containing 3.5 ppm of TEHT for 4 weeks at 3'C. The control blend after the same exposure retains 94r* of its original Mw. 22383016 .F.OOOMKH BFG20423 T -14- Figure 2. EFFECT of TEHT CATALYST LEVEL on tht ALCOHOLYSIS of ESTOL B(HW. 2030/0.60 mole 1,4-BOO BLENO on 4 WEEK/93*C AGING. CHANGES in MWO. mn(ai up (i-mm.hkyl)titahate catalyst u*7745-74-5-1) Map mn (l-ITMYL MOCYL) TITANATC CATALYST (0*7745-74-5-4) MID 4fMr 4 VCEKS 4 M*C BFG20424 T r-M*-XB6r -15- Project No. 7745.74. 75 July 13. 1976 When the TEHT level wet increased to 22 pprn the tame low level of quinollnol (0.045*1 did not five total proti - -jr: but allowed 93% retention of the original Mw after 4 wfcs. at 93" C. The control In this cate retained 86% of the orlflnal Mw, To obtain a completely stable blend containing 22 ppm of TEHT the quinollnol level wae increased to 0.4 and 0.8%. In both catea total blend stability was obtained after 4 wke. at 93"C. The unstabilized control blend lost 13% of Its original after the tame exposure. The difference In original molecular weights in both sets of ex periments Is due to the different columns used In the GPC determinations. TVcnd series No. 5 was obtained with 5 columns of maximum pore slxe - oOn. IOoA. lOOl. 500A. and lOOOA. 567 plates/foot. B'end series No. 18 was obtained with five columns of maximum pore site of 6oA, 100A . 500k. 700-1000A. lO.OOOA. 624. 4 plates/foot. The effect of quinollnol as stabiliser for Estol B (M. W. 20321/ 1.4-BDO blends made with 2.00 moles of 1,4-BDO on heat aging at 93*C. is shown In Table II and In Figures 3 (A, B. C. D) and Figure 4 (A. B. Cl. Table Q gives changes on aging at 93*C. in blend weight average molecular weight (KTwi determined by GPC and free 1,4-BDO content determined by gas chromatography (GC). Two sets of data are given, both sets are almost identical except for small differences in TEHT level which are not expected to affect the aging results. The different original Mw values for both sets of blends, which should be the same, are most likely caused by aging of the GPC columns (the pore else is reduced by shrinkage or contamination). Changes in the columns should not affect the relative Mw values within one set. The accuracy of the GC determinations Is about _+ 0. 5%. Table II data show that the % retention of Mw increases gradually with Increasing quinollnol level from 78% retention of the original Mw at 0. 19% quinollnol to total protection at 0.8% quinollnol after 4 weeks at 93*C. About 90% of the original M, value is obtained at 0. 20 to 0. 30% quinolinol after the same exposure. The GC data on the 1,4-BDO content of the blends agree reasonablv well with the GPC data. Considering each set of data, we see that the retention of the original 1.4-BDO level increases with increasing quinolinol concentration in each set. Taking Into account the experimental error of the method, we can conclude that about 90% of the original 1.4-BDO level is retained at quinolinol concentrations of 0.20 to 0.8% after 4 weeks aging at 93`C. . while without a stabilizer the blend retains only about 50% of the original and about 40% of the original 1.4-BDO content. .Fj BFG20425 T 22383018 -16- Project No. 7745-74. 75 July 13. 1976 TABLE II Changes in MWD and 1.4-BDO Content of Eatol B/1.4-BDO Blends Made with 2.0 moles of 1,4-BDO and Stabilised with Quinolinol. on Q3*C. Heat Aging 7-45-T5 ~EFT 'pom* Qulno'.lnol 69- 1 22 69-5 22 0. 10 69-6 22 0. 20 69-7 22 0. 30 1.4-BDO 3 .1 1.4-BDO SI 1 1.4-BDO Mjl 1,4-BDO Original After 1 m 3 wks. 4 wks. 230 140 (61) 107 (46) 95 (41) 9.0 7. 1 (79) 4.4 (49) 2.8 (31) 229 10.1 9.6 (96) 8.5 (85) 179 (78) 8.4 (84) 217 9.8 9. (100) 9.0 (2) 185 (85) 8.6 (88) 213 8.9 9.2 (103) 9.0 (101) 197 (92)8.8 (991 .74 r (ppm) > Inol (%) M. 18-5 19 1.4-BDO "w * 18-6 19 0.4 1.4-BDO M. 18-7 19 0.8 1.4-BDO Orlgiral After a wks. 158 8.7 105 (66) 4.6 (53) 157 9. 1 153 (97) 8.0 (88) 157 8.5 157 (100) 7.9 (93) All blends were made from Eatol B (M.W. 2032). Numbers In parentheses Indicate percent retention of original values. Mw w.s determined by gel permeation chromatography (CPC): percent 1,4-BDO content eras determined by gas chromatography (GC). Complete normalised CPC curves of the blends discussed In Table Q ere shown in Figure 3 (A. B. C. D) and Figure 4 (A. B. C). The data for the oastablllsed blend In Figure 3 shows that most of the changes take place during the first week of aging with fewer changes during the second and third weeks, and the least change during the fourth week of heat aging. Curves (B) and (C) containing 0. 10% and 0.20% quinolinol show about the same chances after heat aging for 4 weeks at 93*C. but considerably less changes than the control blend (A). Curve (D) for the blend containing 0. 30% quinolinol shows the fewest changes (practically no decrease in 1.4-BDO peak) after heat aging. g.r.OOONKH 22382019 BFG20426 DIFFERENTIAL WEIGHT PERCENT l Figure 3. EFFECT of OUINOLINOL LEVEL on the ALCOHOLYSIS of ESTOL B (M.W 20231/ 200 mole 1,4-600 BLENO CONTAINING 22 ppm TEHT on 93*C HEAT AGING. CHANGES in MWO. im mumm length (A) NO STABILIZE* (E* 7749-74-00-1), ft) 010% OUINOLINOL (El* 7745-74-00-9), ft) 0l20% OUNOLMOL (Etpi 7749-74-00-0), (0) a30% OUINOLINOL (EiO 7745-74-00-7) ----------- ONOINAL MWO ------------M0 f*r I WEEK 03*C ------------ MWO KNr 3 WEEKS t M*C ------------WWO flfttr 4 WEEKS t OS*C G 22383020 . IH. Figure 4. EFFECT of OUINOLINOL LEVEL on the ALCOHOLYSIS of ESTOl B (M.W. 2032) / 2.00 mole 1,4-BOO BLENO CON TAINING 19 ppm of TEHT on 93*C HEAT AGING. CHANGES in MWO. (A) DIFFERENTIAL WEIGHT PERCENT 0.2(0 LOG ANGSTROM LENGTH OF FULLY EXTENOED CHAIN 0.2- 22383021 I t3 LOG ANGSTROM LENGTH OP FULLY EXTENOCO CHAIN (A) NO STABILIZER (Exp. 7T40-74-IB-8), (B) 04% QUINOLINOl (Exp. 7749-74-IB-B), (C) 0J% OUtNOLMOL (Exp. 7748-74-IB-7) --------- ORtBMAL MWO --------- MWO pftpr 4 WEEKS H BS*C 41932 P.r.OOOOMCM BFG20428 19- Project No. 7749-74. 79 July 13, 1976 Figure 4 show* the blends rnn'a'ninr r. 4 IB) and 0.8% 1C) quinolino) along with an unstablllzed control blenc (A*. Here we see that whareas the control blend has undergona considerable changes, both blends containing quinolinol have changed to a relatively small extent after heating for 4 weeks at 3'C. It should be recalled here that (C) (blend contains 0.8% quinolinol) did not show any changea In Mw after the same heating period (Table II). B. Acetyl Acetone Effect on Blend MWD (by GPC' and 1.4-BDO Content (by GC) I found that acetyl acetone (AcAc) la also an effective stabilizer against the alcoholysis of Estol B/l, 4-BDO blends on heat aging, but that It - somewhat less effective than quinolinol. Supporting data are shown in Table ill and In Figure 9 (A, B. C. D). The GPC data Indicate that about 70% of the original Mw value is retained after 4 weeks at 93*C. at the 0.2 and 0. 3% Ac/.c level versus 41% retention for the unprotected control. In the case of quinolinol, about 90% of the original value was retained after the same exposure (Table II). The high value (86% retention) for blend 69-2 containing 0. 10% AcAc Is out of line and appears to be in error. The normalised GPC curves in Figure 5 show that the AcAccontainlng blends (B.C.O) undergo much fewer changes after 4 weeks aging at <>3'C. than the unstablllsed control (A) blend, but changes do occur. Comparing Figure 9 with Figure 3, we see that the AcAc-containing blends undergo greater changes than the qulnollnol-containing blends under the same heat aging conditions. The changes In the 1,4-BDO content of the blends on heating, as determined by GC, are shown In Table III. The data on heat aging at 93'C. (series 6^) show that about 80% of the original 1,4-BDO content Is retained after 4 weeks of aging at all three AcAc levels. The data also show that very little loss In 1,4-BDO content takes place during the first three weeks of aging with a more rapid decrease In 1.4-BDO concentration during the fourth week. The control blend retains only 31% of the original 1,4-BDO content after the same exposure. The blends containing 0.20-0. 30% of quinolinol (Table II) retained over 90% of the original 1.4-BDO amount after the same exposure. Blend aeries 99 shows loss in 1,4-BDO content on aging at 100*C. We see that at the higher temperature the blend containing 0. 10% AcAc loses free 1.4-BDO slightly faster during the entire aging period than the correspond ing blend at Ol'C. No significant differences in 1.4-BDO loss between the two aging temperatures can be seen for the unstablllsed control blends. g.r.ooooacH BFG20429 T "T" 22383022 differential weight percent -i'J- Figure 5. EFFECT of ACETYL ACETONE LEVEL on the ALCOHOLYSIS of ESTOL B(MW. 2032)/ 2.00 mole 1,4-BOO BLEND CONTAINING 22 ppm TEHT on 93*C HEAT AGING. CHANGES in MWO. (A) NO STASILIZER (E* 7T4G-74-G0-I), () Q.N) % oc (E* 7T4S-74-GG-*), (C) a20% MM (El* 7746-74-60-3), (0)00%c (7T45-W-tt-4). -........... ORIGINAL MWO ----------- MWO Ntr 4 WEEKS t GS*C li. BFG20430 -21 - Project No. 7745-74. 75 July 13, 1976 TABLE III Chant** In MWD and 1,4-BDO Content of Eatol B/1.4-BOO Bland* Mad* with 2.0 mol** of 1,4-BDO and Stabillted with Acetyl Acetone on 93*C. Heat Aging "745-75 AcAe *%' 69-1 69-2 0 0. 10 Ww.A 1,4-BDO TZm.k 1,4-BDO 69-3 0.20 TZ^k 1,4-BDO . 69-4 0. 30 1,4-BDO Original After l k. '4 wk. 230 140 (61) 107(46) 95(41) 9.0 7.1 (79) 4.4(49) 2.8(31) 215 185 ( 86) 9.1 10. 1 (111) 8.9 (98) 6.9 ( 76) 234 9.0 9.6 (107) 9.5 (105) 165 (70) 7.8 (87) 244 10.3 9. 9 (96) 8.6 (83) 171(70) 8.3(81) "745-"5 AcAc *i' 55-1 0 1.4-BDO Original After i wk*. # 100'C. 3 wk*. 4 wk*. 9.5 4.6 (48) - 3.3 (3r 55-5 0.10 1.4-BDO 10.5 8.7 (83) 8.2 (78) 7.0 (67) All blnnd* war* mad* from Eetol B, M. W. 2032, containing 22 ppm TSHT catalyat. Number* In parenth**** Indicate percent retention of original value*. Mw wa* determined by CPC; percent 1,4-BDO content waa determined by ga* chromatography. C. N,N,N',N'-Tetra-n-butyl Ethylenedlamlnatetraacetate (TBEDTA) Effect on 1.4-BDO Content (By CC) EDTA or Its odium aalt* are known to be good chelator* for titanium, but In our exp*rlanes EDTA was Ineffective as an Estol B/1.4 BDO blend stabilizer. I feel that the Ineffectiveness of EDTA as a blend stabiliser Is dus to its lnsolublll la the blaad. rurthermore, even If effective, EDTA being a free acid would likely decrease the hydrolytic resistance of Estan* mad* from EDTA-containing blends. To overcome these difficulties, I prepared TBEDTA which la readily soluble In the blends and has relatively low acidity (acid number: found. 0. 8; theoretical AN of EDTA Is 768). 22383024 4* Owe* G  ?EVi<iMgSSy 22- Project No. 7745 -74. 75 July H. 1976 TBEDTA was evaluated as stabU'rr- : a blend made from Estol B. M. W. 2032. and 2.0 moles 1.4-BOO and containing 21 ppm TEHT catalyst. The data obtained by CC and showing the loss of free 1.4-BDO on heat aging are pre sented In Table IV. The data show that a blend containing 0.20% TBEDTA re tains 83% of Its original 1,4-BOO content. This value is very close to the value (87%) obtained with 0.20% AcAc after the same exposure (Table 111, *69-3). But since the control polymer in the TBEOTA series lost much less 1.4-BDO on exposure (50%) vs. the control polymer in the AcAc series (31%l an exact com parison between these two stabilisers is not possible. Nevertheless, the data show that TBEDTA is an effective stabiliser but It appears to be less effective than AcAc. TABLE IV Changes In the 1,4-BDO Content of Estol B (M. Vf. 2032)/ 2.00 mole 1,4-BDO Blends Containing 21 p*>m TEHT Catalyst and Stabilised with TBEDTA on 93*C, Heat Aging 7745-75-161 TBEDTA (%) 1 0 23 0.05 0. 10 % 1.4-BDO In Blend 4 0.20 Original After 3 weeks 4 weeks 8.2 4.6 (56) 4.1 (50) 8.0 6.2 (77) 6.0 (75) 8.1 6.5 (80) 6.3 (78) 8.2 6.8 (83) 6. 8 (83) Numbers In parentheses Indicate percent retention of original values 5 0. 30 8.3 6.9 (83> 6. 8 (83) Other Compounds that have been Evaluated as Estol B1.4-BDO Blend Alcoholysis Stabilisers Of the other compounds that have been evaluated as Estol B-1.4-BDO blond alcoholysis stabilisers, tannic acid showed the most effectiveness. For example, a blend made from Estol B (M.W. 2032) and 0.60 mole of 1.4-BDO. and containing 22 ppm TEHT and 0.8% tannic acid retained 93% of Its original Mwafter 4 weeks at 93*C. Under the same conditions, the unstablllsed control blend retained only 85%, bat the quinollnol-contalning blend retained 100%. The effec tive concentration of tannic acid In the blend was less than 0.8% since most of the additive did not dissolve. Ethylene diamine tetraacetlc acid (EDTA) showed no effect as a stabil iser, but this may be due to the Insolubility of the EDTA in the blend. a.f. BFG20432 T ,2383025 23 Project No. 7745-74. 75 July 13. 1976 Other compounds that were evaluate:1 * ablUssrs and were soluble in the blend, but showed no effectiveness, were 4, 4, 4-trifluoro-1-(2-thienyl>- 1. t-butanedlone: 2. 2'-blpyrIdtne, 1.2-dimethoxy ethane and Inhibitor NPH. 4. Effect of Qulnollnol and Acetyl Acetone on Estol B-1.4-BDO Blend Color Stability During Ambient Storage Discoloration of Estot Bf1,4-BDO blends containing from 0. 30 to 0. 80% of quinolinol was observed on storage of samples exposed to light. The blends were stored In closed screwcap glass bottles on the bench top. After 3 months of storage, it was observed that the top and sides of the solid blend had turned brown, whereas the bottom had changed little in color. This discoloration was observed in blends containing 22 ppm of TEHT catalyst and also in blends made from un washed stannous chloride catalysed Estol B. The discoloration Is definitely a surface effect since the Interior of the sample Is not affected. There appears to be no significant color problem In the blends con taining acetyl acetone. After 4 months storage on the bench top a blend made from stannous chloride catalysed Estol B and containing 0. 30% AcAc showed only slight yellowing. 5. Effect of Qulnollnol and Acetyl Acetone on Estane 5701 A. Polymerisation The effect of 0.08% qulnollnol on the 220'C. NPT*. uncatalyzed, random melt polymerisation of Estane 5701 In the Brabender Plasticorder Reactor fBPR) Is shown In Figure 6. Stannous chloride catalyzed, water washed Estol B (Sec. 1 1G) was used In these experiments. Figure 6 data show that the qulnollnol-contalnlng reaction mixture (7741-74-223)(B) polymerised somewhat slower, and did not reach as high a final polymerlsate torque as the control polymer (T74174*223)(A). But the difference was not great, as would be ex pected since the system contained no effective residual metal catalyst to be deactivated by the chelator. At maximum torque (8 min. reaction time) the qulnollnol-contalnlng polymer had a D8V of 0.64 when quenched In methanol Immediately: without methanol quenching It grew to a DSV value of 1. 57 In 10 days. The corresponding DSV values for the control polymer were 0.67 (methanol quenched after 6 minutes psn. 1 and 1.71 (unquenched, aged 10 days). The effect of a higher level of qulnollnol (0. 5%) on the polymerisation of Estane 5701 was evaluated In the BPR at 170'C MPT-1 using Production Estol B' 'Nominal polymerisation temperature BGH20433 T "T1 22363026 Figure & EFFECT of QUMOLINOL on tire POLYMERIZATION of ESTANE 5701 . (220*C NPT, UNCATALYZEO). sassr -25- Project No. 7745-74. 75 July 13. 1976 1.4-BDO blsnd (Sec. I 3) containing 10 ppm TEHT catalyst (6.7 ppm TEHT by X-ray fluorescence) and Production MD1 (Sec. The data (Figure 7) show that the qulnollnol has reduced the rate of polymerization considerably and that at 12 min. reaction time the torque of the polymerlcate for the qulnollnol- contalning polymer (B) (7742-76-321) la less than for the control polymer (A) (7745-76- 175). At 12 min. reaction time the qulnolinol-rontalnlng polymer had a DSN' of 0. 88 when quenched In methanol Immediately; without methanol quenching It grew to a DSV value of 1.57 In 4 weeks. The corresponding DSV values for the control polymer were 0.99 (methanol quenched after 12 min. pan.) and 1.53 (unquenched, aged 4 wreaks). In this caae the retarding effect of qulnollnol was obviously due to the chelation of the residual TEHT catalyst from Estol B manufacture by the quinolinol. As the unquenched DSV data show, the qulnollnol has only a retard ing effect on the polymerisation rate but does not limit ; ie final polymer growth on shelf aging. The effect of 0.3% qulnollnol on the polymerisation of Estane 5701 eras evaluated In a polymerisation run In a beaker. Production Estol B (Sec. I IF) containing 10 ppm of TEHT catalyst was used in these experiments. It was observed that the quinolinol had a noticeable retarding effect on the polym erisation. The control polymer (7742-75-194) could be stirred for only 1-1/4 min. due to a rapid Increase In viscosity, whereas the polymer containing the quinolinol (7745-75.81) was still fluid at 2 min. reaction time. The effect of acetyl acetone on the polymerisation reaction was evaluated In a beaker polymerisation (7745-75-79) using the same reactants as In the case of qulnollnol above. AcAc was also observed to have a retarding effect on the polymerisation, but less so than qulnollnol. The polymerising mix ture could easily be stirred for 1-3/4 min.. and at this point the viscosity of the melt was not extremely high. B. Original Properties and Environmental Resistance The effect of two levels of quinolinol (0. 10 and 0. 30%) on the proper ties and aging characteristics of Estane 5701 Is shown In Table V. For each concentration of qulnollnol a different set of reactants was used. A level of 0.10% quinolinol was evaluated in a polymer made from stannous chloride catalysed, water washed Estol B (Sec. I IE), Mobay MDI (Sec. I 3A), and distilled 1.4-BDO (Sec. I 20. In addition 0. 30% qulnollnol was evaluated in polymer made from Production Estol B (Sec. I IF) which had been catalyzed with 10 ppm TEHT, Upjohn MDI (Sec. I 3B) and Production 1.4-BDO (Sec. I 2D). .r.OOOMKM BFG20435 TT 8Z0S9SZ lb- Figure 7 EFFECT of 0UIN0LIN0L on the POLYMERIZATION of ESTANE 5701. 41982 n co w o IS5 C5 I i.OCOOKKH -28- Project No. 7745-74. 75 July 13. 1976 Table V dots how that there are torn* /expected) difference* between the two control polymer*. The polvmrr -v.^-'e from Production Estol B (contain* active residual TEHT '-*talv*t' and Production reactant* ha* a higher DSV and * higher T, value than he polymer made from laboratory Estol B Catalysed with ttannou* chloride, then washed (deactivated) with water] Mobay MDI. and distilled 1.4-BDO. The Production reactant polymer also con tain* gel. Aging data Indicate that the Production reactant shows poorer oven aging and hydrolysis resistance than the laboratory reactant polymer. We suspect that the residual, active TEHT catalyst Is the major cause for the poorer aging characteristics of polymers made from the Production reactant system. The data show that quinolinol at the 0. 10% level has no effect on the environmental resistance of Estane 5701 except to produce a very slight darkening in oven aged samples. Considering the polymer with 0.30% quinolinol. we can see that the quinolinol has reduced the original DSV of the polymer by about 1 (3. but has reduced the amount of gal to a great extent. But since the DSV of the quinolinolcontaining polymer is very high, the addition of quinolinol produced no significant changes in the original stress-strain or Ta values of the polymer. Considering the aged properties we see that the quinolinol appears to somewhat Improve the oven aging resistance of the polymer. No quinolinol effect on other aging tests was noted except a very slight darkening of the samples after oven or water aging. The polymer containing 0.5% quinolinol (7742-76-321. Fig. 7B) was molded to a 25 mil sheet and exposed in the carbon arc Weatherometer to* gather with a control polymer (7745*76.175. Fig. 7A) to observe color formation. The data obtained are shown In Table VI. Tabla VI data show that although tha original color of the quinollnolcontaining polymer (B) was better than that for the control on CAWO exposure, the quinolinol-containing polymer discolored more than the control polymer. It should bn pointed oat hare that 0. 5% quinolinol on the polymer is an excessive stabiliser level sines adequate stabilization can be obtained with 0. 3% quinolinol on the blend, which amounts to 0. 2% quinolinol on the polymer in the case of Estane 5701. I expect to see leee discoloration with lower levels of quinolinol in the polymer. An ad' It Impsrts to the polymer. as during processing. pact of quinolinol Is the strong medicinal odor that This odor becomes stronger at elevated temperature*, o W m.ooookh -29- Project No. 7745-74, 75 July 13. 1976 TABLE VI Tho E/fact of 0. 5% Qulnollnol on the Color Formation of Estana 570! on Carbon \rc Woatherometor Exposure Raflactanca (Blue Filter, Baaa 73) Polymer Qulnollnol (%) Houra in CAWO 0 3 5 8 11 16 22 44 88 154 AB 0 0.5 57 59 56 49 55 46 51 41 48 38 43 34 40 31 32 26 26 23 23 21 Tha affact of 0. 30% of acetyl acetone on the original properties and environmental realetance of Eatana 5701 can be aeen in Table VH. The aame Production raw materlala (Including TEHT-catalysed Eatol B) were used in thla atudy aa ware uaed In the above evaluation of 0. 30% qulnolinol. Original property data show that the addition of acetvl acetone haa reduced tha DSV and gal content of tha polymer by a significant amount, but the DSV value la again atlll very high. A reduction In the Ta value ia alao noticeable, but tha Ta reduction cauaed by tho addition of the stabilizer haa no effect on the original atraaa-atraln propartiaa of the polymer. Table VQ data on the aged polymera ahow that the AcAc haa prac tically no effect on the aging characterlatlca of tha polymer except a reduction in elongation after 154 houra in tho carbon arc Weatherometer and poasibly a slightly greater loea in tenaila atrength after 2 ard 3 weeks exposure in water at 70* C. j22383032 * BFG20439 T -30- Project No. 7745-74. 75 July 13. 1976 TABLE VII Effect of Acetyl Acetone on the Original Properties and Environmental Resistance of Estane 5701________ 7742-75 7745-73 Acotyl Acetone (%1 DSV* T./T,. *0. 194 fc 195 0 3.42,43% gel. - 4/171 79 0 .30 2. 18. 3% gel. 1/163 Tens.Str. 300% M. Elonie (pel) (pal) (%> Tens.Str. 300% M. Elont. (pa* > (pel) <%) Originals (75 mil) After 3 days # 140*C.b " 7 days 8500 5200(61) 4500(53) 1400 1000(71) 500(39) 480 520(108) 560(116) 8900 5200(58) 4700(53) 1300 990(76) 600(46) 505 525(104) 565(112) Originals (25 mil) After 44 hrs. CAWO as 154 9700 2800(29) 1500(15) 1200(12) 1600 1700(106) 1500(94) - 470 355(75) 290(62) 200(42) 10200 2400(23) 1400(14) 1200(12) 1600 495 1700(106) 360(73) - 270(54) - 75 (15) Originals (25 mil) 10400 Aftr 1 wk. In 70*C water 9800(94) " 2 wks. 8900(86) " 3 wks. 7500(72) " 6 wks. 1000(10) " 9 wks. 400(4) 1600 1900(119) 1900(119) 1600(100) 900(56) - 475 500(105) 520(110) 590(124) 365(77) 20(4) 10200 1500 490 10100(99) 1900(127) 520(106) 7900(77) 1700M 13) 534/109) 6400(63) 1600(102) 585(11*)) 1000(10) 900(60) 460(94) 300(3) - 30(6) (a) 0.4g/dl DMT + 0. 05% n-Prl. (b) Numbers In parenthesis Indicate percent retention of original value. g e o m ezz i.r. Pwds--wiCs BFG20440 T -31 Project No. 7745-74, 75 July 13, 1976 U Stannous Chloride-Containing Estol B/1.4-BDO Blend Alcoholysis Stability Another epproech to the Estol E/l, 4-BDO blend alcoholysis stability problem is to substitute TEHT polyesterification catalyst, which promotes the alcoholysis reaction, with some other polyesteriflcstlon catalyst which does not promote this reaction, or that easily (preferably spontaneously) deactivates after/durlng polyesterlflcatlon. Stannous chloride dlhydrate (SnCl, 2H, O) has been routinely used as polyesterlflcatlon catalyst to produce low acid number polyester glycols at Brecksvllle since about 1964, following a patented method (5) adapted to Estol B by F. D. Stewart (6.7). We have now found that stannous chloride polyesterlficarion catalyst is practically inactive as an alcoholysis catalyst for Estol B/ 1,4-BOO blends on heat aging. 1. Heat Stability of Estol B/l. 4 BDO Blends Made with Washed Estol B Stannous chloride hydrolyses readily to a water-insoluble basic chloride, Sn(OH)Cl 1\0 (7) which has no apparent catalytic activity with respect to urethane formation and apparently none In the polyesterlflcatlon reaction. The same basic chloride forms during atmospheric oxidation with the simultaneous formation of stannic chloride according to Equation U (7). 6 SnCl, 2H,O O, * Z SnCl* + 4Sn(OH)Cl (Equation H Since the Estol B prepared In this laboratory Is routinely water washed we assume that any residual stannous chloride has been converted to the basic chloride. A. Chances in Estol B/l.4.BDO Blend MWD (bv GPC) Figure 8 (A) shows that a blend (7745-74-18-8) made from stannous chloride - catalysed, water washed Estol B(Sec. 1 IB) with 2.0 moles 1,4-BOO Is practically completely stable on heat aging. The normalised CPC curves of the original Blend and of the blend after 4 weeks aging at 93*C. are essentially superlmpoaahle. The value of the original blend was 1471. After heat aging it was 1491. The changes in the same blend heated for 4 weeks at 100*C. are shown in Figure 8 (B) (Blend 7745-74-58-1). The normalised GPC curves here are also practically superimposable. but a slight shift to lower molejeular weight after heat aging Is apparent lathe bland aged at 100*C. (B). The Mw value for the original blend Is 158JL after heat aging It was reduced to 147& (43r retention of the original value). w to BFG20441 Rgur* a ALCOHOLYSIS STABILITY of HO' C'ANNOUS CHLORIDE DIHYDRATECATALYSEO, WATER WASHED ESTOL B(M.W. 1972) BLENOS with 2.0 MOLES of 1,4-BOO. EFFECT of AODED STANNOUS CHLORIOE DlHYDRATE on BLENO MWO. DIFFERENTIAL WEIGHT PERCENT LOG ANGSTROM LENGTH OF FUUT EXTENOED CHAIN (A) NO AOQCO SoCIg'tHgO, AGCO it M*C (tip. 7749-74-18-S), () NO AOOCO SACIfZI^O, AGCO at IOO*C (Ctp. 7743-74-S8-I), (C) K>0 ppm SuCI^-ZH^, AGCO it I00*C (Exp. 7748-74-38-Z). .............. ORIGINAL MWO --------------MWO iftv 4 WEEKS it THERMAL ASMS r. tO to 00 BFG20442 - 33* Project No. 7745-74, 75 July 13, 1976 Figure 8 (C) (Blond 7745-74-58-2) shows ths offset of a high level U00 ppm) of SnCl, 2H,0 which was add?'1 `n ths foregoing blend. Ths normalised GPC curves show slightly greater changes after 4 wk./100*C. heat aging due to the added stannous chloride than were produced In the control blends without the added catalyst. But, even so, the changes are minor, as can be seen In Figure 8 and Table VU data: before exposure the value was 160JL and after exposure 140l(87% retention of the original value). B. Chanaso In Blend 1.4-BDO Content (by GC) Table VIII shows changes In 1,4-BOO content and values In the two blends, with and without added SnC^ 2H,0, after heat aging. The data on 1,4-BDO level retention ehow similar retention of the original 1,4-BOO con tent (about 80%) after 4 weeks storage at 100*C. for the two blends. The lose In 1,4-BOO content for the blend containing 100 ppm of SnC], 211,0 appears to be slightly greater than for the control blend, but the differences are within ex perimental error. Theee data show that some alcoholysis takes place In the blende at 93* and 100*C. even In the absence of an active catalyst for esterification or urethane formation. The addition of 100 ppm of Si% Cl, 2H,0 has only a mar ginal effect on the alcoholysis stability of the blende. TABLE VIII Changes in 1,4-BOO Content and MWD of SnCb 2H,0-Catalysed and Water Washed Estol B in Blende with 1,4-BDO. With and Without Added SnCl, 2H.O, 100*C. Heat Aelnx 7745-75 SnCl, 2H.O (ppm) 58-1 0 1,4-BDO Rw,l 58-2 100__ 1.4-BDO Mm.k Original After 1 wk. at 100*C. " 2 trite. " 3 wks. 4 wke. " 10.0 7.5 (75) 9.0 (90) 9.6 (96) 7.9 (79) 158 147 (93) 10.3 8.4 (81) 8.6 (83) 9.4 (91) 7.9 (77) 160 140 (87) Blende made from Eetol B, M.W. 1972 (Sec. I IB) with 2.0 moles of 1,4-BDO Numbers In parentheses Indicate percent retention of original value g.r.OOOMCH 22383036 BFG20443 T - 34- Project MO. I 143- .4, I') July 13. 1976 2. Hoot Stability of Blends Msde with Unwashed Estol B. To determine the effect of stannou* chloride polyesteri.'lcation catalyst, residual in blends of 1,4 BOO with ur.w^shed Estol B, on Q3'C alcoholysis ^tabilitv. the following experiment was run. Estol B was prepared using 66 ppm of SnCI|* 2HtO catalyst. After preparation the untreated polyester. (Sec.I!D;MW, 1631; A. N. . 0. 2) was blended with two moles of two lots of 1.4-BDO containing different amounts of water. Blend 2 was made with dis tilled 1.4-BDO (Sec.l 2B) and contained 161 ppm water: Blend 6 was made with Production 1,4-BDO and contained 266 ppm water. Blend 1 was made with distilled 1,4-BDO and in addition contained 17% (weight) of 4A molecular sieves, to assure a completely dry system. A, Changes in Blond Molecular Weight Distribution (GPC) and in Blend 1.4-Butanedlol Content (GC), The results appear in Table 9 and in Figure 9 (A. B. Cl. They show that (A) and (B) (blends contain 161 and 266 ppm of water, respectively) were quite stable during 4 weeks/93"C retaining about 80% (A) of their original 1.4BDO contant and about 86% (B) of their original blend Mw values. These are about the same values as were obtained with blends of 1.4- BDO with waterwashed, stannous chloride catalysed Estol B. It is possible that the small amount of water in the blend hydrolysed the stannous chloride to the inactive, insoluble basic chloride, or that the stannous chloride itself is a poor catalyst for polyester alcoholysis as was suggested by blend 7746-74-58-2 stability (Figure 8 <C) and Table 8). B. The Special Case of Blend 1; Conversion of 1.4-BDO to Tetrahvdrofuran (THF) by Molecular Sieves. The case in Figure 9 (C) whose blend contained added molecular sieves is special and most Interesting. Here a substantial decrease in blend 1,4- BDO content on heat aging occurred: only 11% of the original 1,4-BDO amount remained after 4 weeks/93*C. This large loss In bleed 1,4-BDO content is clearly apparent la the normalised CPC curve of the blend (Figure 90. But it was surprising to find that the 10br value of the blend remained remarkably constant during the aging period, actually increasing slightly during the last two weeks of aging. These findings suggested that much of the 1.4-BDO con tent of the blend had disappeared by a mechanism different than Eatol B alcoholysis. We are certain that the molecular sieves converted most of the lost 1,4-BDO to the very volative tetrahydrofuran (THF) during the heat aging by a cyclodehydrstion reaction (Equation 111). HOCH,CH, CH/THjOH 4A molecular s H,-CHs*Hp (Equation HI) (1.4 BDO) 93*C (THF) For the pretence of a strong THF odor in the freshly opened bottles of aged blends was easily detected. THF odor was absent in all of the other aged imsszzz blends which contained no molecular sieves. On the basis of this discovery an Invention Record proposing the manufacture of tetrahydrofurane via molr cular sieves has been filed (8). r.oOOOSKM DIFFERENTIAL WEIGHT PERCENT 6S0ESSZZ . H- Figure 9. MWO CHANGES in ESTOl 8/ 1,4-BOO BIENDS MADE from UNWASHED, STANNOUS CHLORIDE CATALYSED (65 ppm) ESTOL B on 93*C HEAT AGING. LOG ANGSTROM LENGTH OF FULLY EXTENOCD CHAIN OF FULLY EXTENOCO CHAIN ALL BLEN06 MNOE fiM ESTOL (MW. 1691) m4 2.0 MlM 1,4-600. (A) MM CONTAM 161 PM* MATER (Eap. 7749-79-76-2), (B) 6LEN0 CONTAINS 226 WCttM (Cap. 7746-75-74-8), (C) BLCNO CONTAINS 17% 4A MOLECULAR SIEVES (Ea 7746-78-74-1). ---------- 0RI6INAL MMO -----------MMO tiHr 4 MEEKS it S8*C a.r.ooooncH BFG20446 T  37- Project 7745-74.75 July 13. 1976 The decreasing amount of 1.4-BDO In the blend c nntalning the molecular sieve* mu it be the cauae for the extraordinat anility of Mur during the aging period^ There la alao the very ranonable poaaiblllty that the observed increase in Mw it in fact real and due to the dehydra-coupling of hydroxyl terminated polyester chains. The coupling would take place between two Estol B terminal hydroxyl groups through a linear rather than a cyclodehydration reaction, which would ba facilitated by the molecular sieves, with the forma tion of an ether linkage (Equation IV). Molecular -wfCH^OH HOfCH, Sieves . ^*(CH, )4-0.(CH,)r~+ Ha0 <Equation IV) (Estol B Chain Ends) (Ether-Coupled Estol B Chains) 3, Effect of Stannous Chloride on Estane 5701. A, Polymerisation (Brabender Plasticorder Reactor, 220*C NPT). 1 found that unchanged stannous chloride dlhydrate Is also an effective ure thane polymerisation catalyst, and has about the same effectiveness as stannous octoate. This can be seen In the results of Figure 10. The same Estol B (Sec.l 1C) was used In all three polymerisations of Figure 10 but the 1,4-butanedlol and MDI lots varied: Run 7741-74-429 Involved reactant lots 2B and 3C Run 7741-74-10, 2C and 3D; and Run 7741-74-106. 2C and 3D. Figure 10 results shots that the Brabender Plasticorder Reactor (BPR) torque time curve for the 220*C NPT, random melt, Estane 5701 polymerisation cata lyzed with 65 ppm SnClg* 2Hfi (429) la practically superimposable on the curve for the same polymerisation catalysed with 50 ppm of stannous octoate (103>. After in situ shortstopping both polymerisations with the same amount of 1propanol, polymerlsate torque loss was the same for both. Figure 10 data also show that the uncatalysed control polymerisation (106) was considerably slower. The effect of residual stannous chloride left In Estol B after the esterifi cation reaction oa the polymerisation rate was evaluated less quantitatively in a beaker preparation (7745*75-112) using unwashed Estol B (M.W. 1631 that had beea made with 65 ppm stannous chloride dlhydrate (polyesterification catalyst) (Sec.l ID). Moderate catalytic activity was noticed: the reaction mixture could be stirred for 1 minute before It became too viscous. This should be compared with the customary two minutes stirring time for Estane 5701 polymerisations involving water-extracted (deactivated) Estol B. B, Polymer Orlainal Properties and Environmental Resistance. Environmental aging characteristics of Estane 5701 containing stannous chloride were reported earlier (3A), but the earlier report did not contain a .r.OOOOOKH O b o ssszr; ]pG2044'7 T - 3- Project 7745-74. 75 July 13. 1976 complete *et of data. The complete study is reported now in the following section. All four polvmers in this study w-.-re made from the same 1.4-butanediol (Sec. I 231 and MDI (See i 3E1 lota but the Estol B lots were different. Poly mer 7745-75- 1 12 was made from unwashed . stannous chloride-catalyzed Estol B (M. W. 1631, Sec. I IDi. The molecular weight nf *his polyester is higher than is normally used in the preparation of Eatsr.t- :'7f>l, but the measured physical properties of the derived polymer were practically the same as those of Estane 5701. Polymers 7745-75-I 1 3, 114, and 11S were all made from the same stannous chloride-catalysed, water washed Estol B (M. W. 1184. Sec. I IE). Polymer 113. which is the control polymer, contained no added (supplementary) stannous chloride catalyst. Polymer 114 contained 65 ppm of supp'ementary SnCl,* 2K.O which was added to the polyol blend before the polymerization. And. 130 ppm of supplementary SnCl,* 2Hfi was added to the polymer 115 charge before the polyme rizatlon. The data for the polyurethane original and aged properties are shown in Table 10. Considering the polymer original properties the uncatalysed control polymer (113) Is seen to have lower DSV.less gel. and a lower T, value than the catalysed polymers. Thus, the uncatalyred polymer achieved a lower final molecular weight. The relatively low DSV, Tt and tensile strength values of catalyzed polvrrer 113 are believed to be somehow due to the large amount (130 ppm) of stannous chloride catalyst contained in the polyurethane which also appears ''vs re duced thermal stability, since considerable bubbling was observed when it was subsequently molded at 185*C. No bubbling was observed in Polymers 113 ar.ri 114 when molded at the same temperature. Polymer 115 could be molded without difficulty at 175*C. The faint yellow original color of polymer 112 (residual SnCl- 2HsO> is slightly deeper than that of the control polymer, 113. Polymers '14 and 115 (65 ppm and 130 ppm supplementary (SnCl,* 2H,0, respectively) were of about the same color, ami both slightly darker than polymer 112. Table 10 data show that neither residual nor supplementary SnCl,* 2H,0 at the Indicated levels adversely affect Estane 5701 mechical properties nor color stability to the limits of the dry carbon arc Weatherometer exposure (154 hours). Hydrolysis tests (9 weeks Immersion in 70 C wat?r> show that neither residual nor supplementary (65 ppm) SnCl,* 2H,0 had anv adverse effect on poly urethane physical properties on color or water aging. But thr data do show that 130 ppm of supplementary SnCl,* 2H,O had a slight adverse effect on hydro lysis resistance (stress-strain property retention and color). M.OOCMKM 22383042 T 1 is WV"1 III t an Xfc. N : i 3*323 i^ S*S**S>S# f ^vs. ;1S> f8|F eto ^i<-t st siSi?i8?i r~*4 :st =55ss 5! IJ 3155 4 * * t ^ II fzfg It iUi 332 UUI III s5li 555 3S*f 4* 4 ^ J1 im lh i i HIHUH j, * ill flll || ; H*A|C tf#ics4c4ss4c4s# i ^W1 if i? it Hi 33333 !!! i m m ^ m i a n 555 fsffs I? ilii iliil*sli Iff Ifiig 5 1535 3553lsf!5 |i| lllf *| U\l UUIJH SIS 3f nil uimii Prjcl TT4S-T4.T1 **It M. i erf? y mt HIM uu a 4 . .. vvyvwA ;i fjyUW llli i!j{!|}i? Jiillfl! .M f 8 E ftO S S S # BFG20450 :*** H*~ 41 Project 7745-74,75 July 13, 1976 Ovoa aging (7 days/ 140*C/air) results sSmv `hat the residual stannous chloride catalyst la Polymer 112 (made from unwashed Eetol B) end the 130 ppm of supplementary tannoua chloride In polymer 115 reduced the mechani cal property retention of Estane 5701. Tenalle strength retention eaa about 93% for the control polymer, 113, made from washed Eetol B (but thla aaema high a Inca other control polymera have retained only 87% and 67% of their original tenalle atrengtha after the aamc expoaura) va. about 65% retention of the original tenalle strength In the catalyaed polymers, 112 and 115. However. Polymer 114, containing 65 ppm of supplementary stannous chloride unexpectedly showed only minor reduction In mechanical property level on oven aging with respect to the control polymer. So the effect of atannous chloride on tensile strength retention la not entirely clear. All three Eetane 5701 polymers containing stannous chloride discolored more than the control polymer on oven aging. Polymers 114 and 115, con taining supplementary stannous chloride, discolored more than polymer 112 which contalnod only residual stannoua chloride cats yet. (11 Solution of the Oven Arina "Brown Speck" Mystery, One feature of the above sample discoloration on oven aging was the develop ment of a coarse pattern of small brown specks in the exposed samples which became more pronounced with Increasing oven aging time. The unsuspected cause of this phenomenon and solution of the mystery has been reported (9). Excerpts from that report are Included here since the investigation was an inte gral part of the present study. 2383044 a.r. Pv.it--1 Css BFG20451 T July 13, 1976 Our "detective story" unfolded Uko this. We haws found that thsrmally inducsd alcoholysis of titanium*catalyaod Estol B In storsd Meis with 1.4-butanediol can b corrected by the addition of minor titanium chelator, ir by substituting stannous chloride polyesterification catalyst for the standard Production tetra (2-ethylhexyl) tltanate cats* lyst. In the course of studying this substitution we explored the environmental stability of --stane polyurethanes prepared from stannous chloride-catalyzed Estol B. One of the Estane exposures was our standard 140*C heat aging test in a circulating air oven. As usual, brown specks scattered throughout the compression molded test sample developed in the Estane 5701 molded sheet. Since Research has long used only SnCl, * 2H.O as Estol polyeaterlflcatlon catalyst we suspected that the brown specks might represent smalt, localised concentrations of Insolublllsed tin catalyst residue from the Es*nl R, and set out to determine if this were true. First of all our laboratory Bausch and Lomb stereomicroscope showed interesting detail in the brown specks which we observed and recorded with our camera attachment. Z*speck proved to consist of a small, very dark, opaque, dens- core surrounded by i relatively targe sphere of diffuse brown color. Often there was a distinct separation between the core and its surrounding colored zone. Sometimes .no separated diffuse col>r .'.one was a hemisphere (above/below? ) the core. we asked Peg Mack (D/85I0) to focue on the brown specks with the 3RDC scanning electron microscope and, applying the energy dispersive x-ray analysis capabil'ty of this instrument,to tell us what slaments comprise the brown specks. We anticipated that Peg'a report would be tin and (possibly) chlorlna. But aha reported onl/ chlorine, and In appreciable amount! We asked her to look again, searching more carefully for the metal cation that went with the chlorine. Still only chlorine! Review of ,'Oiible alternative chlorine sources suggested that PVC might be the culprit. But no PVC had been added to the Eatane, and the Estane had not been exposed to PVC (we tho ight). So how did It get In the polyurethane? To shorten the story a bit- we routinely sheet out our Estane polymers on a mill orior to compression molding samples for testing purposes. We used to have the milling dune in the BRDC rubber mill room but quit this practice due to frequent oil anc carbon black contamination of our Eatane stocks, and to patronise our BRDC Plastics Department milling facility. But unknown to us, PVC contamination of our Es'ane stocks daring milling a* our plastics mill apparently replaced the oil/carbon black contamination from the rvbber mill. And this unsuspected PVC contamination mas have influenced Estane stability/stabilisation teste in pact etudiaa. (Fortunately, P. Kelley's eolation mixing technique in his study of Eatane UV color stability largely avoided Estane milling and thus such PVC contamination). Subsequent trial of reveral special precautions shewed that while PVC contamination can be somewhat reduced In our plastics mill operation it Is still present and likely will remain so as Ion-: as PVC Is processed on this mill. We have net directly proven that the offensive Estane brown specks are due to PVC coR'aminant by excising and characterising the tiny cores. But the following experl- me its which 1 performed leaves ne doubt In our minds that the brown specks are ac tuary due to PVC dust BK.7C plastics mill. which la somehow plckod up by Estane during it* milling o.nr.OthCeGMCM 22383045 J2FG20452 T  43. Project 7743-74,75 July 13. 1976 (A) Exoerimests With Estane 3701 Preeared from L-.b SnCL* 2HjQ- Cutlrud Estol B. Eaton* 5701 (7741-7S-436) was prepared In th* Brabsndsr Plastlcordsr Raoctor (BPR) using Estel 3 mod* with 98 ppm SnClg* HtO colculotad on ths final polyester waight. Moat (A) of th* polyurethane was subsequently milled on our plastics mill, but a a mall sample (B) was left unmilled. Then both (A) It (B) wore compression molded as 25 mil thick sheets under th* same conditions and th* molded sheets were oven *g*d for 3 days at 140*C in air. Inspection of th* oven aged samples showed (A) (milled)to be brown In color and to contain many of ths familiar brown specks. But (B) (unmilled) which was distinctly lighter in overall color, was essentially free of any brown specks. So I concluded that th* milling operation caused th* problem. (B> Experiments with Eaten* 5701 Production Lot #649, 338 (from titanium cat*Ivied Estol B>. Reference (9) contains a set of color photographs keyed below which sppear in Ref. (9) Distribution copies (E. C. Schwaegerle, R.R. Bloor, F. T. Boron, D. D. Dltmer-R. L. Markley, H. E. Oaylor, C. H. Lofter-R. W. SmithM. Mack-F. S. Myers, O.E. Ley, L.E.Hewitt, C.S.Schollenberger, RfcD Files (BRDC) (7742-76). Sample 1 Estane compression molded "without milling. ^ Semple 2- Estane compression molded " without milling, then heat aged. ^ Sample 3- Estane milled on BRDC plastics mill,then molded, then heat aged. Sempl* 4- Estane mined with 0.25 phr PVCc on BRDC plastics mill, molded,heat aged.. Sample 5- Estane mined with 0. SO phr PVCc on BRDC plastics mill, molded, heat aged. Sample 6- Estane mined with 1.00 phr PVCc on BRDC plastics mill, molded, heat aged. (a; 23 mil thick (* Sin days/ 140*C/air (c- 10J EPF7MLe*22Tt*l) (Cl Expert--twlth Esthne 9740 n 430. A section of Estane 5740 n 430 extruded tubing obtained ft-- Dele Hhll (ALTC) was heated for several days in the 140*C cir culating air MS. 18 turned a uniform brown, like sample 2 in the photo, but did not develop brown spesks. W Th* adverse effect of chlorine/chloride on Estane color stability is recognised, and has been studied (F. D. Stewart, Research Report, "Th* Effect of Chloride on Estane Color," Projoct 2074-70, Aug. 10, 1970). Th* present iavestlgmtion seems to further confirm this. Apparently, In the case of PVC the culprit Is hydrogen chloride, th-rmaily cleaved from the PVC contaminant during the oven aging of the Estane host sample. Sfroessz: BFG20453 T -44REFERENCES Project 7745-74.75 July 13, 1976 111 Research Report, "Method of Determining the Free BOO (1,4-Butanediol* Content of Estol B [Hydroxy Poty (Tc'ramethylene Adipate) and Ite Blends With BDO by Vacuum Distillation, The Stability of Estol B-BDO Blends to Heat. The Detection of Tetramcthylene Adipate Monomer in Estol B. ", K. Dinbergs, Project 111-43, Sept.5. 1961. (21 B. F. Goodrich Chemical Company Technical Report. "Backbone J/. W. Analysis on Estol Blends", Author, J. B. Haehn, Requested by, J. W. Hockenberry. Avon Lake General Chemical Plant, November 13, 19"7!. A. Research I. O. C."Environmental Aging Characteristics of Estane 5701 Containing Stannous Chloride or Stannoue Octoate Catalysts, " K. Dinbergs to C. S. Schollenberger, Project 7745-75, July 24, 1975. B. Avon Lake Technical Center I. O. C. " Testing Program for Improved Storage Stability of Eatol Blends." John A. Holloway to R R. Bloor. Dec. 18, 1Q74. C. Research I.O. C., "1,4-Butanedlol Determination by Gae Chromatography In Estol B/l,4-Butaaedlol Blends Prepared and Heat Aged at Avon Lake. "K. Dinbergs to C. S. Schollenberger, Project 7745-75, May 13, 1975. D. B. F. Goodrich Chemical Company Technical Report "Evaluation of Chelators and Catalyst In Estol Stability, " Author of J.&Haehn Requested by J. A. Holloway, ALTC, June 9, 1975. E. Monthly Statue Reports (Estane Research) C. S. Schollenberger to R.R. Bloor Projects 7745-74,75, March 1974 to December 1975. F. B.F. Goodrich Chemical Company Technical Report, "Evaluation of Stannous Chloride In Eatol Blende", Author, J. B. Haehn. Requested by E. G. Kolycheck, Avon Lake Technical Center, November 4, 1975. G. B. F. Goodrich Chemical Company Technical Report, "Effect of Storage Time and Temperature on the Stability of Estol 5740 x 610 Blend from S'.ar.-ou* Chloride Catalysed Polyester", E. G. Kolycheck, Avon Lake Technical Center. November 10, 1975, (4) Thermoplastic Polyurethane Melt Polymerisation Studies in the Brabendcr Plaatlcorder. H. Estane 5701i Further Investigation of Shortstop, Catalyst, and Tempera- tore Effects. K. Dinbergs, Project 7741-74, 75, August 14,1975. (5) U.S.Patent 3,057,824, 'Tin Salts as Catalysts in Forming Polyesters," Oct. 9,1962, 1m E. LeBras and D. F. Stahr Assignors to Pittsburgh Plate Glass Co. (6) Research Report, "Low Acid Number Poly (Tetramethylene Adipate) Glycol (Estol B), F.D. Stewart, Project 124-48, Oct. 25, 1966. (7) U.S.Patent 3,463,758, "Hydrolysis Resistant Poly (Ester Urethanes)," Aug. 26, 1969. F. D. Stewart, Assignor to the B. F. Goodrich Company. (8) Invention Record #4413N (BFGCC), "Preparation of Tetrahydrofuran", K. Dinbergs, May 22, 1975. (Placsd In SECRET categoryl (9) Research I. O. C.. "Contamination of Estane With PVC", K. Dinbergs to C. S. Schollenberger, Project 7742-76, Feb. 10, 176. S.F.GOOOtKM 383047 BFG20454 T "1 -45- Project 7745-74,75 July 13. 1976 AC KNOWLEDOVKVr? The author wlahea to acknowledge the prompt and effective cooperation of Ilmara Sockia (0/8510) in obtaining the CC analyala. My thanka are alao xpreaaed to Dale Harmon (0/8510) for obtaining the GPC data, and for valuable conaultatlona. The work of Loia Far rand of our laboratory which Involved the preparation and atabilicatlon of aome of the blenda la alao greatly appreciated. Karl Dlnberga 2238304 41982