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f Serial No. KN-69-6 Copy N^.6 E. I. DU PONT DE NEMOURS & COMPANY 256 VANDERPOOL STREET NEWARK, NEW JERSEY RETURN TO I JACKSON LABORATORY FILE ROOM f,M NEWARK PLANT PIGMENT COLOR RESEARCH REPORT \3 ^ HUMIDITY RESISTANCE - "MONASTRAL" MAROON Pariod Covorad June - August, 1968 (Part time) FILE: 223.91 DATE: 3/3/69 NJ 14071 DUP050081405 KN-69-6 1. Numerical File 2. Research Office File, Newark 223.91 3. Newark Library File 4. M.Hunt/E.Gonick, Pigments, Wilm. 5. W.S,Struve/A.A.Brizzolara 6. F. F.Ehrich/M.H.Gyorgy/B.H.Perkins/Newark Library 7. A.R.Harike/J.Jackson/E.E.Jaffe/Newark Library 8. P. J.Monahan, Newark (Vital Records) 9. N.G.Fisher, Central Research, Wilmington 10. R.H.Wetzel, Newport 11. J. F.Maurer/J.W.Minnich/Colors Research File, Newport 12. H.Matrick 13. Extra 14. Extra 15. Extra 16. Extra 17. Extra NEWARK PLANT PIQ-IENT COLORS RESEARCH REPORT SOBJECT: HUMIDITY RESISTANCE - "MONASTRAL" MAROON PERIOD COVERED: June - August, 1968 (Part Time) Date Submitted: 2/18/69 APPROVED BY: 1. *. ~ate Released: 3/3/69 ABSTRACT Iron pyrophosphate (10%) and aluminum benzoate (50%) were the only extenders which improved the humidity resistance of "Monastral" Maroon, RT-792-D, in acrylic lacquer films over an unextended, well-washed toner. Commonly used extenders such as nickel carbon ate and calcium Staybelite showed deleterious effects. Water soluble impurities likewise showed deleterious effects. Degree of dispersion was not an important factor. DUP050081406 TABLE OF CONTENDS I. INTRODUCTION AND OBJECTIVES II. SUMMARY AND CONCLUSIONS III. PATENT STATUS IV. DISCUSSION A. Effect of Impurities B. Effect of Extenders C. Degree of Dispersion V. APPENDIX A, Office Trade Report, J.A.Lamiet, 5/9/68 B. Patent Proposal CP-98 Page 1 1 1 1 2 3 4 5 6 DUP050081407 I. INTRODUCTION AND OBJECTIVES In May, 1968, F. and F.,Flint, reported (see Appendix A) that RT-792-D, "Monastral" Maroon, had failed General Motors' humidity test. This put the use of RT-792-D and other quinacridones in 1969 automotive finishes in jeopardy of being discontinued. The object of this investigation was to determine the causes of poor humidity resistance of RT-792-D. The factors under suspicion were impuri ties, pigment extenders, and degree of dispersion. It. SUMMARY AND CONCLUSIONS Iron pyrophosphate (10%) and aluminum benzoate (50%) have been found to have a beneficial effect upon the humidity resistance of RT-792-D. This information has been transmitted to F. and F., Flint. All other commonly-used extenders have varying deleterious effects upon humidity resistance, the worst being calcium Staybelite. Likewise, nickel carbonate, alumina hydrate, and blanc fixe appear to be harmful. Water-soluble impurities have a deleterious effect. Alcohol-soluble impurities (Emcol P-1059) do not effect humidity resistance. Degree of dispersion is a minor factor or not important at all in humidity resistance performance. III. PATENT STATUS A patent proposal (CP-98) has been submitted on humidity resistance improvement of acrylic lacquer films by iron polyphos phates (See Appendix B, p. 6 ), IV, DISCUSSION In this study, pigments were evaluated as to their contribution to humidity resistance of a lacquer film by first 2-roll milling with cellulose acetate butyrate resin. The chips were reduced in an acrylic lacquer formula containing the plasticizer benzyl butyl phthalate and solvents. Masstone panels were prepared by drawdown. The panels were baked, then exposed to 150F. and 100% humidity for 16 hours. It was found (B.J.Godfrey) that humidity resistance behavior is dependent on the bake temperature. This can be explained in terns of the degree of plasticity of the film. K. Batzar* has shown that water is transported through the film by osmotic pressure effects. This transport is related to the plasticity or specifically the glass-transition temperature. When this tempera ture is below the humidity test temperature, 150F. water transport occurs readily. The glass-transition temperature increases with decreasing plasticizer content. During the baking cycle, the partially volatile plasticizer benzyl butyl phthalate is partially lost, thus effecting humidity resistance. KN-68-3 DUP050081408 -2 - Two bake ovens have been used which deliver films of different plasticities, a 275F. temperature bake on one oven liberates a considerable amount of plasticizer and a ,,285P. " bake which in effect spends little time at 285F. and, therefore, liberates less plasticizer* The latter cycle gives a film which is more sensitive to humidity and to factors which effect humidity resistance. A. Effect of impurities The RT-792-D rejection by F, and F. was complicated by a change in plant formula made in 1966 which eliminated the final washing of this product, A temporary standard or so-called shipping lot was based on this procedure. Table I shows the result of humidity resistance tests vs. other plant materials which were washed, TABLE I HUMIDITY RESISTANCE OF PLANT LOTS OF RT-792-D Lot Wash Status 275F SL89679 No final Tem.Std. PS97569 Final Prev." 90558 Final Prop." 54749 Final Pres, plant prod. poor good good good "285 "F" Bake poor poor poor % Water Soluble Matter 1.1 0.65 0.48 0.45 Electrical Resistiv*t -n. 1,500 4,800 4,000 10,500 It is apparent that to maintain good humidity resistance at 275F. bake, RT-792-D requires press washing as opposed to centerfeed pressing Which precludes washing. Normal plant product washed to 4000-/t appears to give reasonably acceptable performance at 275F. bake. Extracts of the unwashed SL-89679 showed presence of Na+, Cl", and Ca which would be expected from the final calcium Staybelite laking. Further clarification of the effect of water and alcohol-soluble impurities was obtained by further washing a "Monastral" Maroon presscake, RT-801-P, which had been plant washed to 4800-H- , to 20,000-0- in the laboratory using dis tilled water. A third sample was prepared by washing the 20,000-0presscake with alcohol 2B followed by washing with distilled water to remove the alcohol* The presscake was dried directly and not extended before evaluation. Humidity resistance results are summarized in Table II. A rating system was used in which a 10 rating represents no change and a 0 rating represents total film destruction in which gloss is completely destroyed as is color strength. DUP050081409 -3- TABLE II EFFECT OF IMPURITIES ON HUMIDITY RESISTANCE OF UNEXTENDED "MONASTRAL" ,_____________ MAROON Sample Final Wash Resistivity Humidity Resistance 275F . ,,285F " Plant washed Lab HsO washed Lab alcohol washed 4,800 20,000 60,000 97 10 8 10 8 Thus, it appears that at a 4,800 ohm wash, sufficient watersoluble impurities are present to cause some downgrading of humidity resistance. Removal of alcohol-soluble impurities such as the anionic surfactant Emcol P-1059 does not further improve humidity resistance. B. Effect of Extenders The previously discussed 20,000 ohm sample was treated with various extenders most by co-pulverization but, in some cases, by in situ precipitation. In these cases, the samples were washed to 8,000 ohms. Results are summarized in Table 111. TABLE III EFFECT OF EXTENDERS ON THE HUMIDITY RESISTANCE OF "MONASTRAL11 MAROON Method of Extender % Combination None cII alcium SM taybelite 10 10 Precipitated Co-pulverized Nai ickel cifarbonate 10 Precipitated 10 Co-pulverized Barium sulfate Alumina hydrate 10 10 II Aluminum benzoate 50 Precipitated Iron pyrophosphate 10 Co-pulverized Humidity Resistance 275F. "285F" 10 8 90 90 86 7 0.5 9.5 6 10 3 10 9 9.5 10 Note that all extenders except iron pyrophosphate and aluminum benzoate downgrade humidity resistance. An interesting fact is that calcium Staybelite performs well at 275F, but leads to total film destruction at"285F. ". Thus, calcium Staybelite is a highly undesirable extender for pigments in automotive finishes. It is also significant that precipitated niche! carbonate, although not totally satisfactory, performs better than dry-pulverized nickel carbonate. This suggests that commercial nickel carbonate contains deleterious water-soluble impurities. To further exploit the iron pyrophosphate lead, the latter was dispersed separately in CAB, then reduced and added to "Monastral" Maroon dispersions. These results are summarized in Table IV. DUP050081410 -4- TABLE IV EFFECT OF 10% IRON PYROPHOSPHATE ON HUMIDITY RESISTANCE OF VARIOUS ______________________ "MONASTRAL" MAROON SAMPLES Sample 20/000 washed no extender +Fe4(Pa07)3 SL-86979, unwashed RT-792-D " " " + Fe4(Pa07)3 55865, 5000 RT-792-D, no CaSx " " + Fe4(Pa07) 3 Humidity Resistance 275F. "28SF. 9.5 7.0 9.0 9.5 00 3 1.5 9.5 6.0 9.5 9.0 It has also been demonstrated that Fe4(Pa07)s improves the humidity resistance of clear films. Thus, iron pyrophosphate appears to improve humidity.resistance regardless of the purity of the RT-792-D used. Nothing is known about the mechanism by which iron pyrophosphate operates. It is possible that it somehow lowers film plasticity. C. Decree of Dispersion Several experiments were run to try to determine if degree of dispersion had an effect on humidity resistance. In all cases, results showed degree of dispersion was not important. In one experiment, a sample was chipped with internally and externally added QAAF. In another, ball-milled, sand-milled, and CAB-chipped "Monastral" Maroon were compared. In a third experiment, sand milling was carried out for varying lengths of time. In all cases, 20,000 ohm"Monastral" Maroon without extender was used. Again, no major differences in humidity resistance could be detected as a result of varying dispersion. dc DUP05008141 1 - *5 - VH.Baird, Pigm. Wilm. J.E.Ki'amer.,. Pigm. Wilm. S3. Gorman/L. F,Andrews, PgnWllm0 P.D.Graham,. Pigm. Wilm. R.H.Zabel, Plgm. Wilm, M.runt/S.Gcrtok,. Pigm. Wilm. Pignr.nts Wilmington, Pile W0PSpengeman/K,,B. Claris C ,, R, r&csTTpiwis, C,R, iO^(Cy<r^ir/iC. A. Briz z oiara, f Plgw.``ttewark Pigm. Newark 'Pigments Chestnut Run Pile OFFICE TRADE REPORT F&F - FLINT REPORTED BY: I. A, Lamiet. . / DATE OF CALL; 5/9/6$ /; / V Wes Bullock telephoned to report a number of quinaericlone pigments failed the General Motors' humidity test (my office trade report, 5/7/68). These pigments are in order of increasing stability to the humidity test: " Monastxal Maroon RT-792-D; Monastral Violet R,, RT-733-D; Monastral Violet R, RT-Bl9-Dj and Quincio Violet RV-6902-D. RT-819-D and RV-6902-D are about equal and are considered possibly borderline in acceptability. Thiofast Red Toner MV-6600 and Thiofast Red Lake .KV~d 655 apparently pass this test. The test is now reported to be run " for only 16 hours, rather than the 24 hours previously reported. The temperature of 15GF. and 100$ relative humidity conditions remain unchanged. Bullock indicates that the '69 maroon basically formulated with RT-792-D and the solid red formulated with RT-733-D* molybdate orange, and .iron oxide fail this test. Accordingly, the consumption of quin&cridones for General Motors* automotive finishes for the 1969 model year is currently in Jeopardy unless an answer is found quickly. Chestnut Run has Just placed an order for equipment to run this test; meanwhile, Flint has offered us their facilities for any tests that we may wish to run to help resolve this problem, \ . .. /akr *;?. *< * ' ' VV ',v . V:. "> , DUP050081412 CC: W.S.Struve/A.A. Brizzolara F.F.Ehrich R.D.Nutting, Newport M.Hunt/E.Gonick, Pigts.,Wilm. Newark, New Jersey February 4, 1969 MISS JANE E. MACRUM Pigments - Newport PATENT PROPOSAL CP-98 HUMIDITY RESISTANCE IMPROVEMENT OF ACRYLIC LACQUER FILMS BY IRON ___________ POLYPHOSPHATES (PYROPHOSPHATES) This invention involves compositions of matter consisting of a mixture of an acrylic thermoplastic lacquer film with a ferric polyphosphate (pyrophosphate). Such compositions render the paint film resistant to decomposition by water or water vapor, a property which is particularly crucial to acceptable performance of auto motive finishes. ^A typical thermoplastic acrylic lacquer film consists of poly- methyl methacrylate resin, cellulose acetate butyrate resin, and a plasticizer. When such film, with or without pigment, is subjected to heat and water vapor or condensing water, considerable deteriora tion occurs. The problem is evident on automotive lacquer and is particularly severe in warm, humid areas of the U. S, Such condi tions can be simulated and accelerated by various testing devices, the most commonly type used being the Cleveland Humidity Cabinet. Here paint films on metal panels are exposed to 100% relative humidity at elevated temperatures (80~180F.). An acrylic lacquer film,when exposed to these conditions for a few hours, will develop a non-uniform hazy, cloudy appearance with accompanying loss of gloss, so-called "water spotting". As degradation proceeds, the film will become opaque and lose all reflective ability, A trans parent film pigmented with a colored toner will become opaque with accompanying lightening or loss of coloring strength. Use of iron DUP05008141 3 CP-98 -7- February 4, 1969 polyphosphate simply added to the wet acrylic lacquer produces a film with much superior resistance to humidity degradation. Often these films show no visible indication of degradation even after 16 hours of exposure in a humidity cabinet at 150F. Another advantage of this invention relates to the use of iron polyphosphate as an extender for colored pigments used in acrylic lacquer systems. Colored toners are commonly produced with 10% of a colorless transparent material, often an inorganic salt. One important function that these extenders perform is to allow stan dardization of tinting strength of the product. Often, they will serve another function such as improving dispersibility or light fastness. It has been found these extenders have a deleterious effect on humidity resistance. Among them are blanc fixe, alumina hydrate, basic nickel carbonate, and calcium rosinate. Iron poly phosphate is unique in that it is the only otherwise suitable ex tender tested that does not have a deleterious effect, let alone a beneficial effect, on humidity resistance. To date, we have worked with 10% iron pyrophosphate, A-33-D, and 90% "Monastral" Maroon toner. This composite pigment was pre pared by drying RT-801-P and co-pulverizing the two materials. CAB dispersion was prepared in the Usual manner (described in Example VII, CP-87). The dry paint film composition consisted of 7.5% composite pigment or 0.75% iron pyrophosphate. The following data were obtained by exposing "Monastral" Maroon with 10% of various extenders in the Cleveland humidity cabinet for 16 hours at 150F. Two different type bake cycles were used. One type spends most of the time at 275F. A second type "tops out" late in the cycle at 285F, but the average temperature is effec tively less than 265F. The latter cycle gives paint films which DUP050081414 CP-98 -fl February 4, 1969 are more sensitive to humidity. An arbitrary rating system was used with 10 designating no change and 0 designating maximum change. Ret N.B. 1888-30, pp. 64,65,80,81 275F. Bake M285F. " Bake No extender 10 8 Ca Rosinate, dry blend 9.0 0.0 Blanc fixe, " " 9.5 6 Alumina hydrate, dry blend 10 3 Basic Ni carbonate, dry blend 7 0.5 A-33-D 9.5 10 Other workers have confirmed these results since this experi ment was performed. R. F. White mentions in his Nov. 28 - Dec. 31, 1968 Monthly Summary that A-33-D is the only extender tested which did not adversely effect humidity resistance of "Monastral" Maroon. Likewise, C. W Manger mentioned in his Nov. 19 - Dec. 19, 1968 Monthly Summary that "Monastral" Maroon with A-33-D gives better results vs. a toner control. PRIOR ART U.S. 3,074,895, J. Jackson, 1963, claims coating compositions comprising 10-20% iron polyphosphate with either an alkyd vehicle (enamel) or oleoresinous varnish. Examples include both alkyd enamel and nitrocellulose lacquer. MODIFICATIONS AND EQUIVALENTS C. W. Manger's work indicates improvements can be made on an unpigmented lacquer. The invention should be tested with several pigments. Composition limits and composition of maximum effective ness have yet to be determined. J. Jackson is doing some work on variation of the polyphosphate anion composition in addition to DUP050081415 CP-98 -- February 4, 1969 varying the cation: Jackson's 3,074,895 disclosed use of both pyro phosphate and tripolyphosphate. Also disclosed are use of composi tions containing both sodium and potassium. C. W. Manger has shown A-33-D to be more effective when washed more extensively. Variations in the lacquer formula might be considered such as omitting CAB resin or varying the plasticizer composition. Coverage might be extended to thermosetting acrylic enamels. Combining the polyphosphate and pigment could be tried in several different ways; (1) precipitating iron polyphosphate in the presence of pigment slurry; (2) co-pulverizing the two materials; (3) formulating the additive directly into the paint system with the pigment; and (4) dispersing pigment and A-33-D separately and combining mill bases. The acrylic lacquer dispersion can be prepared either by CAB dispersion, sand milling, or ball milling. INVENTION RECORD The first experiment concerning use of A-33-P for humidity re sistance was begun by H. Matrick on May 14, 1968. The use of this material as a solution to the humidity resistance problem was con ceived within about a week of this date by H. Matrick. On May 21, 1968, a work request was written for evaluation of samples in paint. Paint panels were prepared on June 14, 1968. The following state ment is taken verbatim from F. F. Ehrich's (H.M.> Monthly Summary of July 17, 1968, and represents the first written disclosure of results of evaluation; "Iron pyrophosphate, A-33-D, has been shown to improve humidity resistance on a variety of "Monastral" Maroon samples. The A-33-D was chipped separately, reduced to a mill base and the latter added in a 10% amount to RT-792-p mill bases. In all DUP050081416 CP-98 -10 February 4, 1969 cases where improvement was possible, an improvement was shown. This included low bake and 275F. bake films and samples with and without CaSx, and with varying degrees of soluble salts including the high solubles RT-792-D, SL 86979. This finding has been transmitted to F and F, Flint. Other systems such as clear films RT-819-D, "Monastral" Violet, "Afflair", and "Krolor" are being treated with A-33-D to determine its effect on humidity resistance. Evaluation in TAE-3 with RT-792-D and A-33-D is also underway." dc f H. MATRICK RESEARCH DIVISION DUP050081417 DUP050081418