Document EwgQrxGDMvgYyLrdOyzEng8N

e 0 So m p o e t si mo o r s &. cowm MG* FABRICS AMD FINISHES DEPAfOTEM? fwmmm Division PROCESS &2~03 Mer rat ceir PREPARATXOM OF HWW METALLIC COLOR PARSES Bit S. Ao MILLER HENRI IQ MMffili UBQBMQB1! UffiHR SATE ISSUED? 8/27/62 PROJECT* P-57 - COmiSETERCHAR3P COLOR AEJBSSSfBHT SYSTEM ABSTRACT' A study of the factor that affect the reproducAbility of ."Lfficit" ssetaHlc color panels and the development of a technique to control their effect on panel neproduciMlity* (*) Du Pont Registered Trademark DUP030002264 ! GOmmMD SWXRCWEOT SPRAY SYSW ism A, introduction **,.1 B* Results 2 C. Conclusions **............ 4 D* Recommendations ... .............. 5 II. BISCOSSIOli 0? WAHXG PAKBL PREPARATION A. Background of Problem ................................... .. B Study of problem 6 8 X. Spray Gun ......................... .. a. Gap * needle tip ba Fas Pattern .... a e* Fluid Flow Bate 2. Panel a. dun to Panel Distance .. b, Position in Pan pattern Co Panel Sneed a>a*a**a da Temperature **a.**. 3. Flash UlW nnioum>*t 4, ftf J4k 5* Compressed Air laituitam* aa Pressure . ha 1teim>erature aaaaaoaaaaaa 6 Saamle ........._____. ._______ a Usduetion .a.........*.*..*.. 15 h_ itemnispainira _______________ X> * Agitation ## da SOlVent ................ 7. Environment ae nteiBHfiwtfcmr a. be Humidity ainil*tM c,, Air Flow Bate .......... DUP030002265 TABLE Cffl < (Contd) HE Co Details of C*E.S Bo Future Studio ....................................................... 1, Air-less Spray 23 24 24 2* Steam Spray ................................... lo Appendage ................................... 1 -last Hnoranlum 2a Report on Preparation of"Luoiten* Ifetallie Color Panels ............ 3* Te^erature^Bumidity Plant Reports 25 25 26 31 36 Du Pont Registered Trademark DUP030002266 I A. DhtroOuetion The preparation f metallic color panels through th last of spray techniques .tea long been w<sgnis@d m a prime- SWO0 of difficulty iii color control and' shading due to the lack of reproducibility under moderately varyTM log environments. Da previous years, product had r@ latitude due to their formulation and Mere relatively darker, lees sensitive colors. It me possib1 to reproduce metallic color panels for color, gloss and film properties over a Mid rang of environmental change. i recent'trend has hmn toward less praying latitude -due' to the formulation changes required to I^rov film properties and the limiter metallic color now in vogue. . She 193 colors mm have very little latitude and require xtreMy narrow test method specifications to reproduce color panels. As metallic colors besom mm sensitive to spray variations0 color control could only be achieved on a practical basis through the expedient of 'respraying these color with minor environmental .changes until the panel looked "right." cB*e present practice is to adjust conditions -within the limits of the current test asmorandom to obtain a panel with .a smooth appearance and a high degree of glamour, resulting in paspls being pre* pared on the "wet* side and decreasing the application latitude. The variance in color obtained, although following the present test saorandn*, is greater than'. - the variance that can he tolerated for automotive color control. Shis condition is the - direct result of the inadequate characterisation of the current spraying techniques by the applicable. Test Methods. - She trend toward- light metallic colors containing a high percentage of aluminum has served to grossly . emphasise this lack of spray reproducibility. Fortunately, the application of Instmehtal color control in this area of pigmented finishes soon followed and it became apparent that iwwdiate and positive corrective action was necessary to provide a technique for reproduction ' of metallic color panel and provide the'necessary basis, of instrumental control. . The objectives of this portion of the color study became* 1. $0 define those ' variables inherent in the prepara** . tion of metallic panels and to determine the Big* ' nificance of each m the overall panel variability,, {*} o Pont Iteglstered Trademark DUP030002267 2 2. develop suitable t@shM.quea and appliestion apparatus in order to provide positive control ' of each variable and thus establish overall control of metallic panel reproducibility Success in this area of study ms obviously essential, not only for the future development of instrumental shading techniques, but also for the mintnance of our current position as a supplier of visually shaded Automotive metallic finishes. &&&. An analysis was mad, using colorimetric techniques, of all variables which might conceivably affect the color and,two**tone reproducibility of metallic color panels. Many of the variables thought to hav a najor influence on panel color were found statistically to be minor in effect. 'Sf&s result of this investigation proved ooaclus ively that the panel color variation was primarily a function ofs 1. wetness of the deposited film. 2. Use rate of solvent evaporation from this film. Further study was directed toward.the isolation of each of the parameters contributing to these two factors and defining the extent to which they had to be - controlled. As a result of this investigation, the 17 factors illustrated in Figure 1 were isolated for study. FXQURg 1 FUJI 1 wmS5S5iBmBs 8 VARIABLES 4>AMPl DUP030002268 -3 -.. 1. Compressed Mr Pressure l&a^er&fcura 2. aim Settings Fluid Flee? Bate Fan Pattern Cap, Beedle and Head 3. panel . a. Distance from aun b. position in Fan Pattern o. wg>eratwe of fan! Speed 4. Sample a. Reduction (1) lype of Solvent (2) Amount of Solvent ' ,b. Viscosity ' flempemfcw d. Product Characteristic 5. Environment pamperature ISoatidity Air Flow Bat Of all of .the parameters `studied the environ ment. (spray room) temperature' humidity and tbs rate of flow past the panel were the most Important contributors to panel variability and the least susceptible to positive control. It will be noted from Figure 2 that most of the remaining-variables can be rigidly defined under normal operating conditions. Previous attempts have been mads to .control environmental conditions through the use of . extensive air-conditioning apparatus, mis'approach was believed to be too costly for routine - plant .'operation - and accordingly based on our test results a new approach was made to the problem of environmental control of the air affecting the rat of dry. mis new approach utilised a concept known as the Controlled savirowent Astern (C.B.S.)., Basically 'She C.E.S. derives .all of the advantages of spray room temperature and humidity control at a fraction of the cost. It achieves its purpose through prodding a local air environment'controlled for temperature humidity and velocity in the very area through which the panel must pass during the flash period. IMs air Is essentially ' room air heated- to a high temperature in order to drop the anient humidity below the critical level established in this study. DUP030002269 Equipment sad definitive procedures were developed to permit tbe utilisation of the O.E.s. concept to the routine spraying of production' metallic color panels* Extensive trials over a 9*math period at Process Engineering and the Flint Plant have proven the validity of both the concept and the techniques used for definition of the various spraying variables, working drawings of the apparatus and a definitive proposed test method are appended to this report. Study of the test method will indicate that panels prepared by this technlque can be directly baked without the "flash" period inherent in currently effective panel preparation pro oedures. 0* Conclusions 1. She reproducible preparation of HlMcite"* metallic color panels requires a reproducible orientation of the..metallic aluminum flaks in the film. This condition can only be achieved through positive' control of those factors which affect the applies tion rate and composition of the applied film .and . the viscosity characteristics during the drying stage, fhe Controlled Environment System achieves by rigor ously defining the method of application to provide a reasonably reproducible applied film thickness and composition and then controls the film viscosity ' during drying by reproducing the rate of solvent evaporation from the film. 2. She inherent advantages gained from improved metallic 'panel reproduction achieved under the 0.E.S. tech niques will improve the capability of the Production Division to cope with the manufacture of the newer and more spray sensitive formulations currently comprising our offering- to the Automotive industry. As a result, the practice of "gun-shading"' (i.e., eolor manipulation resulting from spray variations within .the context of-current testing procedures) will fee eliminated under the mere definitive pro cedures developed-under.this study. .. 3. She adoption of the C.S.S. procedures and 'equipment are advocated not only' for "XMolte"* Automotive products but also for Dulux** and -"Eue" products of this nature*. Proliminary tests- at Toledo and Ajax indicate the validity of the application of these concepts to the "Bulux" product range. I) JBu Pont Begistered Tm&mwte DUP030002270 -5- II 40 One area remaining to be resolved concerns the preparation of Automotive'metallic color.standard. w> C.E.S. because of the necessity to obtain reproducible aluminum flake orientation and thus reproducible panels provides panels of loner ''glamour* than the current Automotive standards. Automotive standard preparation is traditionally . geared to provide-standards of utmost gloss and glamour, Shis result can only be achieved through spraying, wet film a condition which sacrifices any possibility of panel reproduction with current spray sensitive formulations. S&m idea of the panel reproduction problem can be obtained when it is realised that a percentage of the standards Bggflg' j&rSfc^feSfefgfeSE *** be Additionally spot measurements mad on virgin accepted standards indicate that their variability exceeds the acceptable' color tolerance for the color. std. 1961 {mmm Sampling) 1962 Stds, * 1963 :'8tds, M * 16 O.K, Color Panels 867-95183 10 O.K. Retains R&sprayed 867-95183 H@qed Control Momnee limits (Panels evaluated by S.T.A. - and B.A.M. for O.K. then read) 867-95183 0.60 20 .20 0.80 .5 .5 2.00 1,20 1*20 3 5 12 2.20 1,5 1,50 12 2,00 1,1 0.75 6.0 1,00 1,00 0.50 6 Xt is obviously impractical to expect Production to consistently match panels prepared under these condltlonsi therefore# the system of standard loses much of its value by resulting in the "gun-shading* necessary to-achieve a satisfactory match. D. install the G.B.S. equipment and program for the preparation of all 'metallic color panels. Although these panels do not match the material as applied at the Automotive plants# this is not '&'ri@Mss problem as the ' customer will b supplied material within closer color limits than under the present' system. DUP030002271 6 It will be necessary to establish the first standard on the C.S.S. equipment then match all standards to this on by adjusting; solvents to produce panels of equal color and twortons, II. BIBCOSSXQS? OF METALLIC MEL PR&?ABMM A. Mokeround of Problem B*e wet film thickness and drying rate must be controlled within very narrow limits so the aluminum particles that arrive at the panel in a turbulent state can orient into a position closely parallel to the plane of the panel substrate. If the spray is too dry the particles- will remain in the random positions as they hit the panel and if the spray is too wet., thermal currents within the film will cause flooding. Bath these conditions have a marked effect upon the L* a, b and Tf value. Changes in wet film are very difficult to characterise as the film viscosity does not remain constant long enough to be accurately measured so an effort was made to correlate wet film weight with film viscosity. Vm high percentage of B*30, Acetone, in the 667 line formulas make the wet film of spray application vulnerable to minor changes in air temperature, relative humidity aiad/or air velocity. Xhe variance in the loss of JFSO between the gun and the panel causes various degrees, of wetness which in turn result in different color and *nr. Q/RAPH 3H0<a /"4(S &A7Z. of OiW6C s/S v/er I Fil m *4i %M pF a?*/* . /sePF 73MP&$47Z*8e. & PvSsr/vtM Pt/<r<5/f7~ DUP030002272 DUP030002273 7 This loss cannot be. controlled but ean be tolerated if the rate of dj*y is eontrolled by a controlled enviromsssat system. Such a system ms developed which would achieve the reproducibility necessary for an I.C.A. program. . The controlled environment system keeps the rate of evaporisation from the deposited film constant so the orientation of the aluminum particles fora a consistent pattern over a wider range of room temperatures and relative humidities. Bo adequate spray facilities were available in the Pe & Po Department for a quantitative study of spray variables. The high number of uncontrollable variables made it inpossible to study one variable while the others were held constant and to determine if the variables were dependent or independent.variables. Most of the studies were qualitative for. an approximate Set of conditions. . They served as a guide to. develop a program to yield the most reproducible panels and give an approximate range of the variable effect. The proposed controlled environment system (C.E.S.) is based on results of work conducted over a year and a half at Philadelphia and Flint Plants. (*3 Du Pont Registered fradeieavic DUP030002274 Bo Ttm importance f metallic color pans! repro ducibility has been brought into shaker focus as the application latitude has narrowed duo to1 increased demand for high initial gloss and glamour. 'This is in sharp contrast to the latitude that was experienced whan producing..55BueoK metallic panels. The customer's added demand for vary close control under a system of narrow latitude has placed a demand upon production that has increased cost due to longer mixer cycle and shading man-hours. Hhe customer* s demand for very close color control may be real or imaginary as his limits of reproducibility are now only an opinion. It is suspected that he is unable to utilise to full ad* vantage the narrow controls being exercised by the plants due to his lack of control of t@mpemtnrehi88idity on the production line and method of application. To minimise our production cost it is essential that practical color limits be established which can be expressed in terras of Adams Coordinate System &hr&&8 4b and This would eliminate the excessive control now being practiced and establish a pattern of uniform color production tailored to fulfill the demands of the customer. will not be an easy task as the whole color control program is in a state of frustration as a result of- decisions being based on opinion and not facts. There are no established limits except those in the minds of individuals which fluctuate broadly depending upon many physical and psychological factors. The eye is an extremely . sensitive organ in discerning very small color .differences so it requires good Judgement to determine and maintain a consistent level of acceptance that Is not adequately defined by numerical values. A basic requirement for the evaluation of color panels is a degree of reliability in the preparation of the standards and control panels that is consistent with the color limits established. At the present tim there is very little latitude in preparing "Incite** metallic color panels and wall deviations in spray conditions change the color of a panel from'an approval to a rejec tiora. it is common practice to respray a color if it is close in the hope that a change in environment is such that an approved panel will be obtained. It becomes obvious that a standard color panel, can only be used for a standard at a given set of con* dltione. In the past, the test memorandum 349y was adequate since the. products controlled Under it had a ' broader latitude for preparing color panels. It is also obvious that it is not adequate for the present po7 line. {*) u Font legistered Trademark DUP030002275 ?mm RSPBOMJCXBXLOT -887-95181 95183 95187 95185 867-95X83 ||7?5999 867* 867*95185 95191 95187 95183 867*95183 5 Panola of Saoh lor 1961 SiasnSards AIl -. 0,15 0*33 0,09 0*22 Mu 0*32 0*09 0*23 0.17 AT l 3* 2, 5 Fastis of 1962 Standard 79 OA 0*07 2*7 1963 Standard* 1*04 0*5 0,2k 4,8 16 Panola of O.K. 1962 Colors 1.80 . 1,32 '235 ' Soli 1.53 I.65 1.12 1.27 2,09 0.83 1,04 0.90 f 10 0oK Retains Sprayed Sass Bay 1*95 1.13 0,75 8,0 9.0 13.0 7.2 6,0 DUP030002276 folXowing the present test mtmmw&xm 349*p very el08@Xya it is possible to prepare two panels front tbs same container with a color difference that exceeds control, limits when minor changes in temperature are encountered* See appendage for "Report on eI<uaite0 .Metallic Color Panel' Preparation*" This color difference is due to different orientation patterns of the aluminum particles in an applied film and is a function of the wetness of the film* DUP030002277 **> 21 ** Color and W d#erease in value as wetness increasesj tterofore& it becomes necessary to maintain a given wet flla thickness for tlm degree of risprodrolbllity required for the X.CA* program. 4be wet film thicJcrossi changes with the followings - l* Spray am ae Cap Needle Zip b Fan Pattern . c Fluid Flow Bate 2 Panel a Cun to Parol Distance h. Position in Fan Pattern c. Parol Speed dft Iteiperature 3o Flash ftae 4.0 Mgxeratun of Bate So Compressed Air a Pressure b* ' Zsnpereture 6 Simple & teduction b* Zenperature c Agitation d .Solvent ? Bivireiwnt Eo Iteiperetur . bo Humidity , Air Flow tote . ' The effect of each variable on film wetness was studied to determine its mhos and type of control that would b@ necessary to yield color panels with the re*s produeibiiity required for X.C.A* program and Autos^otive color control, Ttm wide rang of temperature and humidity experienced throughout the year is shown in the appendaga* teja" fh spray gun adjustments are mechanical adjust* meats that do not vary with changes in nviresmenb but have a marked effect it the wetness of the film* ie method used to centre! the fan pattern is currently DUP030002278 one f Judgement that allows a 'nUt' deviation f film wetness, Zt la proposed that a wet film' weight fr a fixed sat of conditions b the final hack si spray gun. adjustments to eliminate the judgement measurement. the following spray gun factors affect film wetness s * *Bm parts numbers are specified and It Is only necessary to guard against worn parts., they .will cause a fan distortion such' as hour glass figure and affect fila wetness, if the fan pattern is not elliptical In shape the needle and tip should both he replaced, fe &aJ&ttss& -3* . '. 1he fan should be adjusted to the reccimssnded 10*1/2" and have a uniform elllpticai pattern, Hie center of the panel should pass through the center of the fan. Hie fan pattern Is not .a precise measurement and the 10*1/2" distance on ' the major axle of ellipse is one of Judgement that serves as a guide for the first round of adjustment, .After all other spray gun adjust* . ments are set? a final check should he' made on the fan pattern by .measuring a wet film of 100 cc Of standardised 368*0124 reduced with 125 co of sol* 3 vent and sprayed for silKTcumber of passes. This should be compared to an established, standard, {See proposed Test MMormadum) Hie fan can be adjusted to obtain this established weight and still meet the 10*1/2"' pattern, H> keep the fan pattern constant it is essential that the gun.be kept thoroughly clean?'free of worn parts and adjustments secured, . DUP030002279 13 ? ' ttie fluid flow rate of the induced sample is very critical because any variance directly affects the applied film wetness, fBm fluid flow rat is easy to adjust and can bo controlled closely by adjusting the feed to flow 100 ec of *$83 in It .seconds, Hiiis should be checked each day, i effect of flow adjustments on flow rate is shown below. a, Sun to Banel Mstance 2h@ distance froa the gun to the panel is 12." and should be checked daily, A change in distance has a direct effect on the applied film wetness or weight due to the change In concentration per unit area in a cross-section of the fan, l!he applied film is wetter as the distance decreases and drier as it increases. AL AS Ab AW iz-ys. 0 0 0 0 ll~l/2 0,7 0,08 0,1? 3 DUP030002280 14 Tkm pastel should to m% m fch panel holder so that it passes throng the center of the fan. *Bw gun position should be cheeked daily so that the center 14m of the gun is always in the same position. ~ A measurement, can be mad from the gun cap to sene fixed point as a means of control. &BSU&984 Hhe panel speed control is adequate as no change in color and TO was observed by changing the speed 100 per minute if length of travel is constant. 9m panel should pass equal distances on each side of the center line of the fan. Wien two panels are being prepared* the ' . right-hand panel will differ slightly from the 'left-hand panel. This is due to differences in flash time between passes, prefers* it is good practice to always select the panel from the sane . side if two are prepared at the same. time. ' For best reproducibility only'one panel should be prepared. toft -Bight. 0 + 0.14 0 - 0.11 0 - 0.10 0 + 0.5 - ggitmte A snail heat.exchanger was used.as a panel holder and temperature varied from 75 to 180*P, At high temperatures the panels were flooded due to reduced viscosity of the film, She film is thermoplastic and there is internal flow at high temperature. Controlling the temperature at a constant 78F increased the reproducibility. At 90 there Was a slight orange peel. Use heat exchanger was not studied further al though it affected the rate of dry of the applied film because at the desirable high temperature the film was adversely affected. Hhe C.E.S. panels maintain a. constant temperature of 120*F. 3 EMmjMmL t@ flash %im bad no .effect on the color after panels' flashed 10 minutes* Use proposed C.&.S. eliminates the flash. DUP030002281 - 15 - :r o The tenperature off the bake is not critical for color as the cosgiarison of two bake 40P apart is not vary largo* ISO9 l60 Ah As Ab ATT 0 0*25 0 4 0.32 0 0.10 0 1.0 The length of bake in excess of 20 ninutes had no effect on the color or TO. 5. Sawmlto imam A difference of 2#/sqin* ha very little effect on color. A change fro 55#/q.in* to 50#/q.in. has the following effect on color. Ah A Ab ATT 0 4 0,44 0 ~ 0*15 0 * 0.01 0 . 4 1,5 The air pressure is usually consistent but a simple alam device could be put on the line ahead of the transformer if wide fluctuations are coanon. ** BggBte The tenperature of the compressed air has a minor effect on the wetness but no change in color was noted when the compressed air temperature was' held between 75F and 95F. 'Temperatures in excess of these values should be corrected hy installing a large surge tank in the spray room. 6. * MBSHm The 867 line is reduced to a specific viscosity with a range pf two seconds., The resolution of the test is 2 seconds 'at 25 C. The'tempemtur is not measured when testing viscosity and range fro 22*0 to 28*0 which results 'In a 'viscosity change of two seconds. m total range-for the test is 4 second which would man a 30$ differens in the amount of solvent, used for reduction. The effect of change in the amount of reduction solvent is shown on-the following page. DUP030002282 15A DUP030002283 /5 B DUP030002284 Serial II157 156 17783 16 MdMtipn .for 100^j o c . 867-95183 100 cc 130 cc solraat ggtesfe Ah A* A* & TO 0 * 0,15 0 + 0,85 0 * 0,08 0 + 13,0 It was found that .a fixed amount of solvent for reduction' gave significantly pm reproducible results and the mil. difference in viscosity had no effect on the flow through the gun or on the panel viscosity. Uha following table shorn that the viscosity of the material before, reduction has .very little effect on the reduced viscosity. 867*95183 nsssms. vise. Init0 Vise, Before Deduction 60 sec. m sum 100 cc 867 m&LSolvent M8 41,5 41,5 41,2 4 teaper&tur of the reduced material should be held between 75*P and 85F as extreme temperature will affect color. e. Agitation . m the study, it was also found that the saapl increased considerably in viscosity due to loss by vaporisation when the agitator was used end the booth air velocity was 30Q. ft/ain. If possible, a closed cap system should be used and no agitator, Iher has'been no difference observed in agitated and 3ion*agitsied reduced sample* in our Studies CXicitw^ only), . d, Solvent fh rate of vaporisation of a solvent in combination with an 867 line Is m of the most lE^ortant factors in the film- wetness. () So-font .Registered ffladsmarlc DUP030002285 11 DUP030002286 vs 18 To maintain constant film wetness for eonslatent color the solvent loss between the sun and the panel must he constant* Hs loss of solvent from an 867 11a product lot down with 37767 la 2% from the gun to the panel at 8oP* She- loss varies with temperature rad humidity as shown on the chart below* Change in film weight or wetness causes changes in OT and color* Hi tm approaches thd temperature of the surrounding air at a distance of 3 to 4 inches from the gun* . At the gun tip the temperature is 10 to 15*F. lower* To overcome, this problem an attest was made to set up a method of controlling the temperature and humidity of the -air surrounding and --affecting the rate of solvent loss around the fan* Hie ' funnel or homshaped DUP030002287 19 device as ahem was Med but failed as the booth air flowed back Into the fan due to air currents created by the fan* Aft attest was also mad to supply controlled air to the funnel near the gun but this also failed to stop the air currents flowing back into the mouth of the funnel* Shis should be further explored as it is the minimum investment to control the loss of solvent between the gun and the panel for maximum repro* ducibil&ty. it may be possible to shield the fan from the surrounding air by a fin and coil arrange* mnt that had a constant temperature Shis would be based on the assumption that high-humidity would not be a problem. ' She loss between the gun and panel can. be reduced . to a minimum which no longer affects color by select* lug suitable solvents for ranges of temperature and humidity, (see Chart * Pag 20.) It was found that if the film wetness remained constant no change in color developed regardless of the solvent used to maintain the constant film characteristics under wide changes in environment. An attempt, was made to us the Shell Shin Film Evaporator to develop data for use in adjusting sol* vent structure to correct film wetness that changed due to temperature and humidity. Shore was no correlation between the Shin Film Evaporator . results and applied film wetness. She loss of solvent in combination with "Incite** and the high degree of atomisation had no relation to the solvent evaporating rates obtained by the Shell .Shin Film Evaporator, She data shown are for reference us only. $} Hu Pont ..Registered trademark DUP030002288 ~ 20 DUP030002289 * gi f3 DUP030002290 ZlA o DUP030002291 22 7* * i rate of solvent loss from the applied film on the panel is a function of the environment and temperature is the most critical element, > control the rate of dr? it is necessary to main0 tain the temperature of the environment surrounding the applied film of the panel while it is flashing* It was found that the most reproducible results were obtained by maintaining a temperature in excess of any spray room temperature* 190**? was selected and found to be easy to maintain regard" less of room temperature. With the controlled. environment at ISO9? for the flash period; a uniform metallic pattern was obtained as the aluminum particles orient under a standard rate of dry, b. Humidity Tm relative humidity is very critical at temperature* below 80F if it increases above 3Q$ As the temperature rises* higher relative humidity can be tolerated and does not affect the wetness of the film, 3fs relative humidity will affect the wetness of the applied film if it drops below 15$ as the temperature rises over 85?, Shere appears to. be a wide tolerance of relative humidity as it changes with temperature, in most situations the temperature and relative humidity . Increase or decrease in the saw direction -and prevent extras conditions in the environment. It is impossible to outline the "comfort some" for constant solvent evaporisation with'the .equipment now available in the F. & ? Division and extremely - costly to control a narrow "comfort sons," Jt is possible to avoid most of the effect of changes in relative humidity by maintaining the spray room at 80*P minimum as most high temperatures are acccm* panied with higher relative hwidities, * Attuetautete 'raperature and 'relative humidity become more critical as the air flow rate increases, There is no advantage to maintaining air flow rates in excess of that required to- remove the overspray, The present rate of 300 feet/minute is difficult to maintain and 150 feet/minute was found to he-adequate for spray dust removal and easier to maintain at a constant -rate, . At the lower rate the film wetness varies' less under temperature and relative humidity changes so panels are -more urnifom in color and TT, DUP030002292 23 If the fix wetness 02? wet film weight can be controlled within 4 5$ and rate of dry held eon stapt* excellent reproducibility can be obtained * Wet fix weight can be maintained by* (X) Dcsaplet@ airc@nditimSng with a range of 5* and 20$ relative humidity. (2) Changing solvents so the rate of vaporisation is constant under a range of temperature and taaXdlty0 (3) Dbe a slow evaporating solvent free of H*30 to minimise difference in loss in combination with a controlled environ sent for the flash period, (Details discussed at end.,} (4} rnmrn the H30 from the formulas and substitute a slower evaporating solvent to use with controlled. enviroswept system, (3) Use a combination of two proposals, C Details of Controlled EnvXvormant darefee C,S was devolved late in 1961 as a means of avoiding the wide fluctuations in tempei^ture and humidity experienced at BtXladelphia Process .iglneering when praying wtocit@w metallic panels. () Du font Registered Trademark DUP030002293  24 Slid purpose of the C.E.S. is to control the on**0 vironaiant of tbs applied film of a panel so its sate of dry is constant, 1h constant rate of dry allow* the aluminum particles of a ooastant wot film to orient in a umifema manner so reproducibility of color and TS is at a maximum. i system operates at 120* which is easy to maintain by heating the spray room air. liaising the temperature avoids high humidity which reduces the rs producibility. NO attempt was made to control the humidity as its effect in this range of temperature did not adversely affeot reproducibility. 1. Hie Controlled tovironwent System operates at 120 for controlled flash temperature. 2. Uses a slow evaporating solvent H-79/M7 equal part. MnSmu loss over range of room temperature. 3. Fixed velocity Igoykin. Easy to control. '4. . Fixed reduction 100 cc material 110 cc solvent 5. Filtered air gives cleaner panels. 6. Us flash time before balsa. 7. Six-p&ss system ll/2 min. flash for 24 coats. 8. System minimises variance in color but does not eliminate it. 9* For maximum control air temperature of fan must be controlled. 10. Panels show a very light orange peel and are higher in TO than regular standards. 11 limits of reproducibility over a range of 80 to 95 "F, Studisa oh da Ob 4TO t t & 0.10 0.30 0,10 2.0 Ha airXess spray would decrease the variance but would not eliminate it as some solvent is required to reduce viscosity. Hie unit is impractical for panel preparation due' to cleanup time required. Panels prepared had a good- appearance and if a simple unit can be designed it may prove useful. DUP030002294 o 2* & 25 Shi system appears to have a very good potential as It would he ecsapletely independent of temperate and humidity as all of the faster solvents would he evaporated. If used In conjunction with the C.S.P a very high degree of reproducibility should result. $h panels appear darker and in the direction of the film obtained on the automotive production line. . Further work is planned to determine the feasibility of a steam system and its reproducibility. . iooendage 1. fast 2. Report m Freparation of "incite** Metallic color panels 3 T@a^erature*RMidity Plant Reports DUP030002295 26 *6002 (or 8000 such assigned no.) SPRAY TEOHRIQIIE & PAL pWr seewpparaarr aatt*iio#n hm- as/vpr.a-rrng TerAt*ssry\tmit PURPOSE To provide a detailed procedure for preparing "Imoite"* AorySXO'&Mqus? color panel in the mat reproducible, maimer^ IRllgffLS CT &e method consists of preparing panels under closely ooEwoDSd air temperature and velocity. The temperature of the air .in the C.E.S.*!* normally above the temperature of the spray . rro% in order to* reduce or eliminate the effect of fluctuations in room air environment. * Controlled Environment system (Sparger System) .amro - This is a proposed control method and has been used extensively for Instrumental Color work at Flint. It has been evaluated for reproducibility over a wide range of temperature. It is the most reproducible method of preparing "Incite** metallic panels at the present tim, 1. 4* x 6* aluminum panels undercoated with 88l94027* fray M. 0.- Sealer* reduced with 37767 Apply one double Coat and air-dry minimum of five minutes. 2. Common sense strainer or lOO-mesh screen. 3. Environment Control . see drawing FN-13119 PM-13120 Blueprints may be obtained from process Engineering* Philadelphia Plant. 4. Spray Gun a. Machine Spray - Be Vlltlaa ASA 502 .with AH5-E , tip (Order AVHj OI-E Tip and gasket which, includes the hV~Tlpa AOA tOt-B-Beedle and 30 Cap. (Hsfer Be Vilblss Parts List 1.820*A.) h. Guns should be inspected monthly for worn parts. The gun should be completely overhauled and new parts installed where necessary. e Fluid Stem 3/8" Inside diameter. (*) fits .font Registered Trademark DUP030002296 27 * Pag .2 4/13/62 5 Air gauge on gun Se WMss Bra6054, 0*100 pounds* 6* Air valve on gun equipped with positive open and close* To dinner K"8 (H"47/IHF9 equal parts)* 8* Oven (260? 4f ), 9 Xf necessary to clean panels, use vz-1204* B not oil or use rubbing compound, 10, JDaylight lamp {350). 11, prison Leap,, 12, esi Panel Beciprocatiag -unit, a. Eclipse b, 2 0A**85 dears for a>l Bati c,.. l&inch stroke d. Panel speed * 822 inches/sdnute & 25 Anchas/teinute, 13, Spray booth lineal velocity of 150 feet/mia, + 25 mt/w&.n0 14, Spray row maintained at a minim temperature of 80*9, 1, Standardising Spray dun a. Adjust the air regulator to give an air pressure of 55#/sq,isa, 2#/sq,in, at the gun with trigger wide open, depressed air temperature should be between 75F and 90P, b. Set the gun' so that the ear of. the cap is 11 from the panel, te center line of the gun should be perpendicular, to the panel, and in line with the .center of the panel. After'gun is set, measure distance frost ear of cap . to top of Panel reciprocating unit and record so it can be checked daily, c. Adjust the fluid flow to a rat of 100 cc of H583/14 seconds* d. Adjust fan to torn a uniform 10**!/2W pattern* DUP030002297 e. ihs above adjustments are a guide and should be checked by spraying six passes of standardised 868*OX24 whit base reduced with $8 solvent at a ratio of 100 oc of 0124 to 125 cc of ff"8** The panel should be prepared with the spargersoperating at 12QF fhe wet film Is the most critical property of a color panel and must be vesy closely controlled for wet film weight. The wet film of six continuous passes should weigh 0*62 grams .03. The wet film weight can be changed by adjusting the feed or fan .and soms Judgement is required to make adjustments so the feed rate and fan are as close to specification as possible, .mnor adjustments are best made with the feed. The fan is limited by the formation of an hour glass figure or nem^iformity from top to bottom. f* After changing any erne adjustment .on the gun, all adjustments should be roeheeked until all are in balance* If unable to adjust gun to give the specified film weight, ...it will be necessary to change solvent reduction under extreme conditions by increasing thejgoflH'9. As a fInal check, spray a panel of 67 line and check dry film build. It should be 2.0 mils to 2.2 mils. ' Check wet film weight once per day. Check feed rate and panel distance once per day. Check fan pattern once per week. 1. The C.E.S. should he placed so that panel travels 1/2w from the face of the spargers. 2. The temperature should be set at 120*? to obtain a temperature of 120*F at the"-panel.. This can be measured by attaching a thermometer to the panel and completing a spray cycle. Adjust air temperature if necessary to get 120*p at the panel. 3. . a@ average air flow over the face of the spargers . should be 150 feet/kinute. This setting should be made with a clean filter on the blower and the filter should be cleaned, weekly to maintain uniform air flow. The dampers should be locked la place after adjusting for specified air flow. - equal parts H**47/B-79 DUP030002298 - 29 Pag 4 4/13/62 1, Us umderco&ted pawls With m end of the Averse side . marked "Top," 2* Set panel in holder at 90 angle to center line of spray gun and so it passes In front of spargers at equal distances fro top and bottom edges of spargers. The panels should be set in the same position at'all times, 3. Spray as follows t a. Reduce 100 cc of material with 110 ec of equal parts of H**47 and H-79* Avoid hot or cold . solvent and material. Reduced sample should be between 75P and 85*?. b. Spray nix single coats. e* Plash 1-1/2 -minutes with panel in holder passing behind spargers. d. Repeat for number of required coats specified on formula. @0 Place in oven immediately and bake 20 minutes at 260P. f, Isc&Mn for color. See Qkwmmmm PHROAOTMIS It is important that daily checks be made of all apparatus. The equipment has been used for the l.C.A. commercialization program at Flint with the following resultss ' At one set of conditionsg Resolution Ah A& 4b 4 TT OolO 0.15 0.10 2 DUP030002299 30 G Bang of temperature and' lusaiditars T6F 20 tun, to 95*F - 500 HH* ?ag4 5 4/13/62 At 4& ii> 4TT b 20 0.50 020 4*0 Sfal varianoo- %& lem than th variance found in now standards and 0K eolo?.panels* ^SJUSHg April 24, 1962. SIIFERSEBIMO W349F - 9/12/60# - to ube th sparger strati of preparing color pan!.# Emm go A# mum DUP030002300 cc* mm B* I* SOTS o Wo Ho Wo AH0RRS.0R Ho B V&CDK! - PE. Wo Bo EBWABPS Philadelphia. Plant <$tea 18 1962 COLOBMWCHOT? COMB AWHSSWMf 8SSIBN (JP-57) Wm? OB .FWAWngM OP "KB8 WmSSOQ COMB PAltUd _____ _____ In the preparation of "incite"* attain color panels# It has boon found that tte present 867 Mis -is ex&mmlj sens!tlve to any change in drying conditions op In tte wetness of tte applied film a film wetness is a function of mm variables which can be com* trolled but tte most iaport&at variable Is tte room temperature which cannot be controlled for tte desired reproducibility* to high par*1 centage of B3Q# Acatone# in tte material reduced for spray appllea* tioo and tte high percentage in tte reducing solvent result .in wide variations in film'wetness and color variation due to. varying losses caused by changes in tetspemtursp ft present problem of -roproduei* bility is that tte variation.in color due to enviroiaent changes exceeds tte limit of variation required for production color control Although the specifications of tte present W3ii9p are followed the color variation is excessive ais is a problem to production control and preparation of standards tore are two solutions One is to rewrite tte M,, with much narrower limits and tte otter is to adopt another method of preparing.panels that allows a wider variation of ambient conditions to details of each are outlined in this report tore are-certain basic concepts of a color control standard - that must be adopted for 867 Mm color control due to the fact that minor eavirosstosit changes affect the color to color standard can only be a standard .for one set of conditions f therefore# tte standard color panel# to have, a true standard value# must show tte following % 1,, Mpesatur# of tte air 2^ Telocity of tte. air at tte 'panel 3 Relative humidity of tte air 4. Film thickness or film weight 5 Solvent reduction 60 tot film weight for a given' number of passes If these are known and can be reproduced within' narrow limits and the following are in line with tte tost memorandm# excellent reproducibility should results (*) M Font Registered Trademark DUP030002301 To Fluid flow 8. Panel disteaeo 9 Fan pattern - 10 Panel speed U. .Qua* cap* needle* and head 12 of passes 13. Flash time 1A. Oven temperature for hake 15. Length of bake 16. Air pressure The limit of the first three variables for the present method of preparing panel are not teem but they appear to be very narrow She best "guesstimate" is a followss 1 Temperature of air 82 F. 2* 2e Velodty of air 300 ft. per minute 50 ft. per minute 3 Humidity 30$ 10$ These extremely narrow limit would require a very .costly installation to accomplish .the necessary control A second basic concept to be adopted to avoid the above costly installation 1 that a production control system need not use panels that match the customers* production line applications Two : \ . customers using the sate material will not apply it under the same conditions and will obtain different colors i therefore* the most . important factor is to give the uisifom material This can be ' -accomplished by using the best method available for color control although the color of the control panels will be different than the color obtained, by the customer* If this is objectionable to Sales* - it may be necessary to prepare a second set of panels for customer usage under conditions similar to those used in his plant The saw material, would be used to prepare both control panels and customer standards but each would have a separate set of conditions on the back ' If a new control system could be adopted* it would overcome the present problem as panels now prepared for standards are held very close for film appearance So obtain this film appearance* it Is necessary to prepare panel on the wet side which is an area where reproducibility is very difficult and any slight change in environment bring about a change in color* Although- these panels are prepared within the limits of the test method* they cannot be matched at higher temperatures Without using a retarder . It is proposed that the sparger or controlled environment system be adopted that produces panels that are on the dry side with .a very slight orange peel that is only perceptible at specific angles and is much more reproducible over a wider range of conditions* These panels would not match the color obtained by the customer but the system would give us a wider rang of reproducibility at a minimum j cost* It is estimated that the cost per booth would be $6d0 to $800* It should be recognised that there will still be seme minor color variance due to changes in room temperature* this temperature change affects the percent of H*30 lost between the gun and the panel which give various degrees of film wetness* This variance' could be reduced by increasing the percentage of H"79 for higher room temperatures DUP030002302 To adopt this sysbe it would bo necessary t have .standards prepared with the same film characteristic ..its order to hav# maxims control to a given standard. Thia would require'a complete revision of the present method of proparing standards and would also reqair all "tacite"* producing plants to have controlled onvirormnt equipment to use the new standards. - in alternate method would he to establish a .mster stan* . dard on the controlled environment system and use It as a guide to prepare standards with the present equipment. This could be access pushed by hanging the ambient air in the spray booth or changing solvent used for reduction. The easiest way to accomplish this would be when new standards are prepared for a model year. The 1963 stair* dards have been prepared but 1964 standards could be a realistic goal. If the system warranted immediate installation for 1963 colors it may be possible to use present standards with a minor off-set. K study is scheduled and an answer to the problem should be teem in the near future. ' Controlled Environment System ' ho Outline of System 1. Operates' at iso* for controlled flash temperature. 2* Oses a slow evaporating- solvent H-79/li"47 equal parts. Wiwa loss over range of mm temperature. 3. Fixed velocity X50/fain. Easy to control. 4. Fixed reduction 100 cc material 110 cc solvent 5* Filtered air gives cleaner panels. 6. Ho flash time before bate. To 6ixpsss system X-1/2 min. flash for 24'coats. 8. System minimises variance in color but does not elJa&nabe it* 9. For maxima control air to fan must be controlled. 10. Panels show a very light orange peel and are higher in TO than regular standards. 11. limits of reproducibility - 867-95183 AL 0.20 A ^ fc 0.30 Ah 0.15 ATT 2.0 () Su Font Begietered Trademark DUP030002303  3%. - Bo Summary 0 1. Xm present 867 him requires a mm test wssorandwi tm dOBid rogroducibillfey. So 10 produce color panels under the new teat OEnnte will require- installation of high cost equipment throughout the MvisiOIt. 3. Alternate method would be to adopt the controlled .nviroit system which gives a film with different characteristics . a. Bewtyg@ panels must be acceptable to Sales. b If not acceptable, two sets of standards could he adopted Co If present study shows that the prepared 1963. could b used with the O.E.S. using sis off-set in oolar, then conversion of control units would only be necessary* do It would be possible to prepare new control standards to match C.E.S. standards and adopt system for 1963 colors. ' 4. -If change is made, it'must be m a Divisional basis and probably should be with a model year change* 1 ) 5. be 0.E.S. is an improvement on the present system and has proved to be adequate for X,CA* color control Hiero will still be sens minor variations in panels due to loss of H-30 between the gun and panel at varying amount due. to room temperature changes. 6. Automatic spray gun will have to be converted to a stomas 1.5 minute .flash s4'*coat system. 1. Bequest Sales 32evlopwnt laboratory to supply the following on all standards at time of preparations - Air temperature Air humidity Air velocity ^ Film thickness or weight Hie above data should also be recorded when standards are prepared. Adjust solvent for uniform standard preparation. Seduce booth.air velocity to 150 If spray dust removal satisfactory. Xoveatlgate possibility of controlling t#^ratur of air to fan with present air oondltidaar and us in .conjunction with d.i.s. DUP030002304 35 - 6* me voixm rtfuettou flop saantai Is to# s^nyad, ? hit mlom should to formulated to glv the @@m fite ehsrate^iU^s at oomtant oguAltlaMU MMilL f r q c b s s mxinssna i Eo A Mllm DUP030002305 36<e mw Tucker So. San Fran. Chicago Fort Madison Flint T1 oledo Phila, HIGHEST TEMP. .. Hwcm. 95 *F 95 R.H. 287 92 F 38$ 109? 95$ . 92*F m 82P m 100? 98$ HIGHEST TEMP. &0WB8T Hmm># 95 F 25 HH. 91*? 30$ 93? 32$ 92 F 37$ 82 F m 95? 20$ LOWEST TBHP, 77 F 95 R.B. 67? ' 67 B.H. 7Q*F *$ 9 w 78 F 35$ 7@P 95$ LOWEST T8MP. mi Mil 77? 25 HoHo 59? 38$ Ro ll, 70 5$ 90 59$ 78 F 20$ 80? 25$ 1961 Jfan. mb. tech April mi 3vm Ml sm. sept o 0Ct. Hov. Dec. The "comfort gone" for good spray reproduelbllity under the present system appears to ;b 78? to 03P with a relative hmldity between y'"'i 20$ and 4G$* She higher the temperature, the higher the tolerance for - 'relative hunldlty. is most objectionable conditions are high ienperatsar and low humidity and low - teisperatw and high hua&dit?. DUP030002306 37 $V X X. 'V< V {> >* <- , V w x /X X %,,/ X- X X ^,*5*** .v a x /\'yyX/X.\/X-/XvXKaX, TM' . x -"xv . /V- , W ** -tfAW5WS.V55S* / / \. *****,,, s x.. .*. ***** v- -'S*^ ' ?**Xh *^ XjES!,, **fS"#->*& ^ /twfer&fi/rc J'k/a'fyiSc Loco L/zg/y It Is lapoMlbX to define the limits of good reproducibility m m equipment is available to run a srl@ of twists* ifce large Muw f air required for a spray booth mate It iitspracfeleal to control to the harrow limit required over the wide rang of temperature and humidity experienced at each plant DUP030002307 DUP030002308 38 o flBBSHBlIBBS ftosaaroh Btporfc Iluatell Laboratory Homing and Bappling off ifetalllos 9/11/51 by J* Ho H8ifcsb??ges? Homing ana mppUm Jfctauioo xx 2/27/52 by Jo j l iai&tbg@r ^J Study off Working Proparfci off Aufeonobive Metallic finish 3/26/62 by Jo A, Mt&mlU DUP030002309 i 1 ; . sc *o (X ' ,6-. O S o \J 1 N i j I ? -3 |1 $% ,^ ttO-JUJ o v o TERM CODE 43 - ttO-Jlli; ^ a 5; i________ - -g] * cs > Su j -3 O oca Oc .8uj o H-U c > Q CO Ul' ttO-JUJ . ^ CO C] i t ' 'M A Q TERM CODE 2 L ________ _______ Vo> > - fi o o 8 O' <0 8 .6 o ,5a >o o .Vo . > CN Oia v3 > O 3 fi '.: 'Ui' <J V- UKZOU J? O' o s ------- ---------------------------------------------------------- <2 2 >* ^2 >-- ; >0 1 >- 7 ZI* ' u j u j rt SSni* <->3 /J oz / vTi `V at V * / 't 4-0 rs QUJCLH 1 - t ./ ' / -* DUP030002310