Document rBgoOdJovmgQekOb8eYm6vngq

Indexed CC: C. W. Theobald, Film. F&F) In J. A. Klacsmann, " " ) film F. D. Lawson, P. B. Cochran, D. McBumey, J. W. Nestor, R. B. Davis, C. F. Kalb, ft It ) H ft ) In Turn H n) S? 81 91 u) IV ?l ) % In Turn J. C. Richards, Newburgh 0. H, Bullitt, Jr, Exp. Sta. L. G. Wise, Exp. Station G. I. Mulholland, FljKtTfJnij G. T. Vaala, Film. F5W'Uun /( R. W. Laurrell, Film. F&F File: 1865 Report No R-62-26 A?h 8 2 E. I. du Pont de Nemours & Company, Inc. F. & F., Research Division Marshall Laboratory Research Report IMMERSION TESTING OF V54 MAINTENANCE PAINT SYSTEMS Date Issued Period Covered Project No. Previous Reports Notebook No. 3/23/62 9/1/61 - 2/15/62 P-2700-E None 7525 TABLE OF CONTENTS Introduction........................... Page 1 Objectives....................... 1 Summary and Conclusions.............................................................................. 1 Action Taken or Proposed. .............................................. % Patent Situation. .......................................................................................... 2 Publication Proposal. ..................2 Discussion. .....................................................................................3 General....................... 3 Organic Chemical and Solvent 'Resistance. ........................ 3 Percent Resistance. ................... ..... ................... .. 4 Effect of Air-Dry on Resistance. .......... 4 Effect of Temperature of Solvent......................................... .5 Water Solutions. ............................................... ....... 5 Experimental Details. ... ................... ..........5 DUP030009403 IMMERSION TESTING OF V54 MAINTENANCE PAPIT SYSTEMS OINinnTiuReHOaMDMUfMCMTMIOMWN: In order to hasten and augment acceptance of V54 mainten ance paint systems it is necessary that the resistance of subject systems to long-term immersion in a wide variety of liquids be known. Successful performance would allow wider V54 penetration into the Marine field (cargo tank interiors, ballast tanks, deck paints, dock equipment, etc.); Petroleum field (storage tanks, pro cess equipment, loading racks, piping, etc.); Chemical field (pro cess and storage equipment for solvent, monomers, and intermediates, loading racks, tank cars, piping, etc.); and Maintenance Finishing field (water storage tanks, locks, dams, bridges, gas holders, etc.). OBJECTIVES: To determine resistance of V54 Maintenance Paint systems to long-term immersion in a wide range of solvents, water solutions, acids and alkali, edible oils, crude oils, etc. SUMMARY AND CONCLUSIONS t It should be noted that the main objective was to deter mine ultimate resistance properties which we believe could be accom plished by artificially aging all paint systems. I. V54 systems will not be generally useful for tank interiors. Specific instances will undoubtedly exist where satisfactory per formance can be expected if the coating is thoroughly cured. Tests indicate this cure may be obtained only at elevated temperatures or after extremely long periods at lower temperatures. II. Thoroughly cured (baked) V54 coatings are better than allcyd, phenolic, and epon ester coatings, about equal to vinyl and poorer than catalyzed epoxy, urethane and inorganic (Dimetcote*) coatings for resistance to organic solvents and chemicals. III. Air dried V54 films are slow in curing to a resistant state. Eight weeks cure at 77F . - 50% R.H. has not produced an acceptable degree of resistance in V54 Red Lead Primer (7067-5001), to the more active solvents. In contrast catalyzed epoxy has a relatively high degree of resistance after a short drying period (one day at room temperature). *-Inorganic Zinc Silicate Coating - Amercoat Corp. DUP030009404 2 Although a urethane system gave erratic results a. much faster rate of cure was indicated than for the V54 primer. IV. Standard topcoats perform no better (and in some instances are inferior) over V54 primer than over their own recommended pri mer. V. V54 coatings are poorer than any of the controls tested for resistance to water solutions because of their tendency to soften and/or dissolve in alkaline solutions. This softening is a surface phenomenon which occurs quickly and is worse on air dried samples. VII. The superiority of V54 coatings in resistance properties to alkyd systems makes them useful as exterior coatings for solvent and chemical tanks where only occasional spills are encountered. ACTION TAKEN OR PROPOSED: Any recommendation for the use of V54 systems where sol vent resistance is required will have to be answered on an indivi dual basis as is the practice in the maintenance paint field. When an improved product is developed additional immersion testing on a smaller scale will be required and the program will be designed to take advantage of the developed background. PATENT SITUATION: The work has not led to any patentable discoveries. PUBLICATION PROPOSAL: No publication of the data of this report is currently planned. However, when the work is complete, bulletinization of the results may be useful to Sales, DUP030009405 3 DISCUSSION: General At present there is no universal coating system that satisfies the requirements for resistance to the wide range of materials handled, shipped, stored or processed in the Marine, Petroleum and Chemical Processing industries. Catalyzed epoxy and inorganic systems have a high degree of resistance hut have other shortcomings. Dimetcote, a widely used coating, is a three package system with a mixed pot life of 4 hours, requires scrupu lous surface preparation, cannot be applied in thick films (over 5 mils), costs $22/gal. with a coverage rate of 225 to 300 ft.2/gal., must be chemically cured for 24 hours or heat cured at 350F, must be cured between coats if 2 coats are required and must be kept moisturefree for 24 hours after curing. A four page instruction booklet accompanies each gallon of paint. It is the practice in the field to make recommendations on an individual basis - in some cases a field trial in the cus tomer's plant being required. In some instances the customer must resort to exotic and expensive coatings such as porcelain, stain less steel and other alloysj Saran* sheeting, etc. to obtain ade quate resistance. The results obtained in this study in no way detract from the usefulness of V54 systems as exterior coatings but rather solidifies their advantage over systems such as alkyd, phenolics, and epon esters. Organic Chemical and Solvent Resistance Results after 12 weeks immersion are presented in Table I. The principal or initial cause of failure is listed although more than one type of failure frequently occurred with the same sample. Samples were inspected after being immersed one day, weekly there after until six weeks and then every other week. Failure noted as being after 14 days, therefore, indicates that the failure occurred between 7 and 14 days. When some softening of topcoats by solvents occurred this was not considered a failure if no dissolution was noted and if the topcoats recovered hardness within one day. *-Dow Chemical Company DUP030009406 -4- As previously noted V54 coatings are generally better than alkyd, phenolic, and epon ester, about equal to vinyl and are infer ior to catalyzed epoxy, urethane and inorganic coatings. This is, of course, a general statement because of the variation of failure in different classes of solvents between the coatings. As expected the alkyd control had the least resistance while the epoxy and inor ganic coatings performed best. Several chemicals produced no fail ures, while several were quite severe, especially the primary amines, where all coatings failed. Percent Resistance (See Table I) In an attempt to give an overall rating to the V54 systems relative to the various controls a formula, was devised which takes into account the number of failures as well as the immersion time to failure. This formula is useful, of course, only for giving the average rating of the various systems against each other in this group of test solutions. The % resistance figure cannot be used in predicting resistance to other liquids, or even to individual mem bers of the present group of test liquids. 84 days x 34 solutions - days failed x ^q q % Resistance - 84 days x 34 solutions No failure equals 100% Resistance Effect of Air Dry on Resistance Oven cured V54 Red Lead primer (7067-5001) showed no fail ure after 16 weeks immersion in butyl acetate (BA) and methyl iso butyl ketone (MIBK) and failed by lifting some time between 1 and 2 weeks in ethyl acrylate monomer (EA). These three solvents were selected as a basis for determining the aging period required at room temperature to develop solvent resistance of the Red Lead pri mer. After 8 weeks cure at 77F - 50% R.H. the primer has not deve loped an acceptable degree of resistance, the samples failing after 1 day in BA and EA and 2 days in MIBK. High spot tests indicate that air dried (10 days at 77F - 50% R.H.) printer is softened more by alkaline water solution than oven-cured primer. A catalyzed epoxy coating air-dried one day at room temperature has not failed after 12 weeks immersion in BA, EA, MIBK as well as in acetone and ethyl acetate. Fresh epoxy failed more rapidly in acetic acid and raonoethanolatnine than did the oven cured epoxy sample. DUP030009407 -5 Results with urethane topcoats were erratic probably due to lack of control of curing environment. A much faster rate of cure, however, was indicated for urethanes as compared with V54 primer when both were cured in the Constant Temperature Room. Vinyls cure rapidly but even baked films have poor resis tance to strong solvents. Effect of Temperature of Immersion Solvent Generally, weak systems fail more rapidly at higher immer sion temperature (12QF) . The more resistant finishes were somewhat softened but did not fail by lifting or blistering and regained hard ness quickly after removal from the solvents.. More tests are planned to further define time required to attain resistance as well as the effect on resistance of immersion temperature with proposed (fast drying) systems. Water Solutions Results after 10 weeks immersion are presented in Table II. V54 systems are softened and/or dissolved in alkaline solutions. At high pH (9.6) the V54 Tank White (7025-5001) flakes away and at lower pH (6.1) is softened. The Red Lead primer exhibits a surface soften ing at pH 6.1, pH 7.7 and pH 9.6. This softening is apparent by the ease with which the surface can be removed by rubbing. Reimmersion (after removal of the surface by rubbing) produces the same soften ing of the new surface. This softening occurs quickly both on ini tial immersion and reimmersion. None of the controls exhibit soften ing to any extent except in NaOH or H2SO4. Air dried V54 Red Lead primer was softened more readily by buffer solutions at pH 6 and 9.6 than were cured samples. EXPERIMENTAL DETAILS: I. Substrate Hot rolled steel rods (4" x 3/8") DUP030009408 6- II. Metal Treatment The rods were "sandblasted" by rolling overnight in a steel ball mill charged with sand and toluene. The rods were then "pickled" for a short period in dilute sulfuric acid/triethyl amine solution, washed with water, rinsed with acetone, and stored in a desiccator until needed. III, Sample Preparation Printers were applied by dipping and air dried overnight. Topcoats (where used) were also applied by dipping and air dried overnight. Where two coats were required an overnight air dry was employed between coats. All coatings were applied at their recomm* ended thicknesses. IV. Aging Period Except where noted all samples were aged one week at 150F. All samples were held in the laboratory until sample preparation was completed and all were immersed in each solution at the same time. V.. Systems Tested (See Table I) 1. V54 Red Lead Primer 7067-5001 2. V54 Zinc Dust Primer 7067-5004 3. V54 Tank White 7025-5001 4. Alkyd Primer 67-746 5. Epoxy Primer 825-8031 6. Phenolic Primer 373-763 7. Phenolic Printer 373-759 8. Vinyl Wash Primer 818-012 9. Vinyl Primer 818-011 10. Vinyl Intermediate 818-003 11. Alkyd Enamel 28-5049 12. Catalyzed Epoxy Enamel 823-8021 13. Phenolic Enamel 353-922 14. Vinyl Enamel 802-006 15. Urethane Enamels 813-906 and 813-901 16. Epon Ester Enamel 840-66951 17. Dimetcote (Amercoat Corp.) HEK:dk 3/23/62 DUP030009409 1o 4 *!'*. <tSj k _ Q. 59 z Kl s IU ui-o >-- y;*o II ? 3 St** J5 nO DUP030009410 ITABLE ,,, !CKe mic a I ResistAMCE of CuBed MAiNtewAMCE Pa in SystcMS (Ail SysteMS Ac'4OneWek A 150 f:) Ta He n Resis Ian c e of Canc<JfHANteHANce PAmi SvsttMS"WAtfeR SolotlONS Pr ime r V54Rtd Leac I " " " " // V54Zn Oust // n n u n No n e AlKyd Epoxy PhtNohc Topco/vt No n e V54 Whitt AlKyd Epoxy P he n o Iic Ur e THa NE ViNyl No n e V54 White AlKyd Epoxy PKe n o Iic UREthANE ViNyl V54 Whitt AlKvd Epoxy PhtNO lie UREthANE .U P.P vR.ft-m ^5 ]L |-Pk B& -V k WBWI-' kBBJiiB jii s. D L 7.. .. STF SOS s 771 Re s u ^s iOWEEks Imme r s io n 5S $ 41 1 I D'Dissolved B'BlistcRtd Ls Lifted S'SoftENed Mu mLir XiMdicAtes Da y s To Fa iIu r e ,,! QuestioNAfek AJJf'fcJ* M PhENohc Ed o n E-s Ier QiMgtcotE No n e Ji Q MOI AllStfte*s/Utd 0m& Week ni I50*F. DUP030009411