Document 4aB1mgLmORLVDqaGG2Y1XbDpV

FOR COMPANY USE ONLY WP-BSI-66-5 May 16, 1966 E. I. DU PONT DE NEMOURS AND COMPANY, INC. (<?./) PIGMENTS DEPARTMENT r et ur n t o EXPERIMENTAL STATION MARSHALL LAB. LIBRARY /2/c '< INTERIM REPORT FORMULATION OF FLAT PAINTS SUBMITTED TO: R. B. EATON SUBMITTED BY: 0. B. VJILLCOX Distribution Dr. Madison Hunt - Wllm. Dr, Ely Gonick - Wllm. H. B. Clark/W. F. Spengeman - C.R. Dr. H. H. Schaumann - Newport Mr. R. M. Luckring - Newport (2) Dr. R. D. Nutting - Newport (2) Mr. C. E. Rick - Newport Dr. N. G. Fisher - Central Research Dr. C. M. Olson Dr. C. J. Carignan Dr. W. E- Dunn Mr. T. D. McKinley Dr. R. H. Wetzel Pigments Central File - Wilm. Experimental Station File - Bldg. 335 Newport Library N 29322 TO COMPANY USE ONLY WP-ESI-66-5 INTERIM REPORT FORMULATION OP PLAT PAINTS by 0. B. Willcox (brd) Project 8215/731-05 DUP030000002 FOR COMPANY USE ONLY WP-ESI-66-5 A. in t r o d u c t io n TABLE OF CONTENTS Page 1. Objective-------- ------------<_______ ____ ________ 1 2, Importance of Study--------------------- ------ ----- l 3- Background------------ ----- ----------- <-->- l B. SUMMARY 1. Work Done-------- --------- ---.--------------z 2. Important Results----------------------- ------------- 2 C. CONCLUSIONS AND RECOMMENDATIONS---------- ------------ -----------2 D. PLANS FOR FUTURE WORK-------------- --------------------------3 E. DISCUSSION 1. General Applicability of Study---------- -------3 2. Flat Paints-FunctIon and Properties------ :-- 3 3- Glossary--<---- ---------------- *---------------------------- 4 F. OVERALL EXPERIMENTAL PLAN-------- ------------------------------5 G. RESULTS---------------........... .................................... ----------- - 6 H. DETAILED EVALUATION--------------- ------------ -------- ------------ ------- .14 I. SAMPLE FORMULATION--------- ------ - -------- ------------- -------- 15 J. VEHICLES-------------- ------------ ----------- ----------------------- ~---- 16 K. METHODS----------- .............. ................................ ................. 16 L. DISCUSSION OF WINDOW EFFECT------------............... ----19 REFERENCES------------------------- -------------------------------- --------- 21 DUP030000003 FOR COMPANY USE ONLY WP-ESI-66-5 INTERIM REPORT FORMULATION OP FLAT PAINTS A. INTRODUCTION 1. Object!vie (a) The major purpose of the work reported here was to provide a body of quantitative information on the formulation of flat paints and rapid methods for screening evaluation of new pig ment candidates prior to more detailed study by experienced formu lators, 2. Importance (a) Flat paints are possibly the largest single end use of white pigments. They are complex systems. No single general detailed explanation of their theory and performance is found in the literature although there is an abundance of narrow studies of specific aspects and compositions. These were mostly written prior to common use of Kubelka Munk scattering coefficients, A typical literature reference is "Fundamentals of Formulating Flat Finishes" (l) which contains a number of formulations but not a single film measurement or other literature reference. A single coherent study was required to reveal inherent advantages of new pigment types with a minimum of formulation study for each candidate. 3- Background (a) Report WP-ESI-63-12 by the writer was an initial brief, uneducated step towards the objective. Our own understanding DUP030000004 FOR COMPANY USE ONLY -2- WP-ESI-66-5 and methods have since been improved and tested in use. Reference will be made in the body of the report to pertinent literature. B. SPMMARY 1. Work Done (a) A coherent body of information has been assembled using a single alkyd flat vehicle, R-900 TiOg, and calcium carbonate extenders. The major formulation variables covered were T102 con J centration, extender particle size and total pigment concentration. The effects of these on the following film properties were determined: TIO2 hiding efficiency *3 Total film hiding Film porosity Gloss. I (b) New laboratory methods of preparing paints on a miniature scale (13 cc or less) and accurately determining the important properties were devised. Suitable equipment was acquired and personnel trained in these methods. ri $H 2, Important Results ms? (a) An improved quantitative understanding of conventional flat paint systems has been outlined. (b) The information has been useful in the evaluation of new pigment candidates. C. CONCLUSIONS AND RECOMMENDATIONS (a) Large Improvements In flat paints are possible. (b) Extension of this study to Include the finer points of formulation and performance would be useful. DUP030000005 FOR COMPANY USE ONLY - 3- WP-ESI-66-5 (c) The information, should generally apply to latex type and other extended systems but the study should be repeated for latex paints, D. PLANS FOR FUTURE WORK (a) Repeat on a limited basis for a typical latex vehicle. (b) Carry out a similar study on a radically different type of extended pigment now under study. E. DISCUSSION 1. general Applicability of Study Most flat paints are used on interior surfaces. Interior semigloss paints and some exterior paints employ extenders and the general considerations developed in this report might be pertinentThey might also apply to any pigmented system containing extenders or an extender-like component such as paper, 2. Flat Paints - Function and Properties A flat paint is designed to provide an adherent film of uniform color and low gloss over a base of different and uneven color, gloss and porosity. In addition, it is expected to be stable in storage, easily applied, dry rapidly, allow working with the applicator for some time after the film has been applied without change of color or gloss in the dried film, show little color or hiding change during the drying process, fill minor cracks and sur face imperfections, have low odor, be resistant to various stains and water spotting, easily cleaned, scuff resistant, maintain its DUP030000006 FOR COMPART USE ONLY -4- WP-ESJ-66-5 properties on aging, provide a base for repainting and be low in cost. 3* Glossary (a) PVC, pigment volume concentration, is the volume of pigment (TiC>2, extender or any inert insoluble component) divided by the volume of the pigment plus the volume of the binder or film forming components. (b) CPVC, critical pigment volume concentration. As the PVC of a film is increased, its properties show a gradual change until the solid inert particles attain a certain packing density and the void spaces are exactly filled with the available binder. Increased pigment beyond this point results in film voids and abrupt changes in film properties. This is the CPVC. The CPVC is deter mined by the size, shape and size distribution of the solids, their surface area and the degree of dispersion and wetting of the solids by the binder. A complete discussion can be found in Paint Flow and Pigment Dispersion (2). (c) "Free,,Ti02 PVC, This is the volume of T-iOg divided by the volume of Ti02 plus the volume of binder in the dry film. (d) % voids. The volume of connected air voids in the dry film divided by the total film volume (air voids plus film solids volume). (e) Syj. This is a measure of the scattering value of a unit weight (or volume) of Ti02- It Is defined here as the DUP030000007 FOR COMPANY USE ONLY -5- WP-ESI-66-5 Kubelka-Munk scattering value, Sx as determined from Ross curves in report PTW-8-2-64, of the film when spread at such thickness that an area of 25 cm2 contains 0.03 gs TiOg. This is equivalent to a spreading rate of 2 lbs Ti0g/8l4 sq. ft. or 12 gs/m2 or a TiOg thickness of 0.113 mils. Unless otherwise noted this value is for films oiled with Nyjol. (f) Si mii. This is the scattering value for a film having a one mil thickness of dry film solids. The actual film may be thicker if it contains air voids. (g) Crowding refers to the decrease in TiOg spacing when a coarse extender replaces binder in a constant volume of paint film. (h) Window effect. This is a coined term to suggest the fact that light passes directly (without scattering) through large transparent areas of a film which may be extender particles, unpigmented vehicle, or air voids, with a consequent apparent loss of TiOg efficiency, (i) Scattering is the "reflection'' of light by refraction % and diffraction. (j) Hiding is the obscuring of a background by scattering and absorption of light. P. OVERALL EXPERIMENTAL PLAN 1. Experimental Blocks a, TiOg without extender in both alkyd flat and alkyd gloss vehicles. DUP030000008 FOR COMPANY USE ONLY -6 - WP-ESI-66-5 (b) Paints at 65 PVC with a single extender (Camel-White) and "free" Ti02 varied from 10 to 40 PVC. (e) Paints with free Ti02 PVC of 30, Camel-White and total PVC varied from 45 to 75. (d) Repeat of C series with each of three extenders of the same composition but increasing size. (e) Repeat of C but 25 wt. % of the Camel-White replaced by Celite 28l. (f) Paints wLth extremely large particle size extender (glass beads) to develop window theory. (g) Stain, scrub, and mar resistance of selected paints. (h) Testing predictive ability and utility against a commercial flat. G. RESULTS 1. TiOp Without Extenders. Table I and Chart #1 This familiar chart shows the decrease in Ti02 efficiency as the PVC increases and a maximum hiding for a constant film thick ness at about 30 PVC. The absolute values depend upon how well the vehicle wets and disperses the Ti02 and the size, shape and crystal structure of the T102. It is also shown that a gloss vehicle reduces flocculation and results in an Sw curve parallel to the flat vehicle but about 25$ higher. All films in this report, unless noted otherwise, were dried by placing on horizontal aluminum shelves with air circulating DUP030000009 FOR COMPANY USE ONLY -7- WP-ESI-66-5 at 35-4o C. When thick wet films of a flat vehicle with R-900 dry slowly at room temperature Sw Is lower than those with the more rapid dry as shown /by Table 1C, The films at .004" show nearly the same value as the rapid dry but at .006" the values are lower than the rapid dry except at the highest concentrations where values close to the average for rapid dry are obtained. All this is indi cative of a time dependent flocculation most noticeable with low concentration, thick wet films and slow drying. It is noted that the Sw curve Is nearly straight between 10 and 40 PVC. Considering the TiOg to be perfectly spaced in a simple cubic array and expressing the Interparticle distance as a fraction of the Ti02 diameter, we find: PVC Fraction 1 5 10 20 40 52.4 3.45 1.19 0.74 0.38 0.10 0.00 A plot of the fraction vs. Sw is nearly a straight line with only a slight decrease in Sw at 10 to 15 PVC. Stelg (3) considered rhombohedral packing the closest packing of spheres. In this case, when the spheres touch the fraction is 0.0 and the PVC 74. The fraction Is 1.0 at 9*25 PVC, It is assumed that, since the diameter of Ti02 particles are about one half the wavelength of green light, scattering will reach a maximum at a fraction of 1 or from 5 to 10 PVC. Accurate measurements are difficult below 10 PVC. DUP030000010 FOR COMPANY USE ONLY -8- WP-ESI-66-5 2. Constant PVC Extended Paints. Variable Free TiO^ PVC Table IIA shows that the Sy, In a 60 PVC paint extended with fine particle size ground natural calcium carbonate corresponds to the S-w of Ti02 alone in the vehicle but averages slightly higher. The slight difference may be due to several factors. As indicated by the Sx 0/D the films contain air spaces which could allow greater separation of the Ti02 in effect a lower PVC. Part of the air might be in closed pores resulting in Ti02-alr interface and increased hiding. The fine extender may hinder flocculation of the Ti02 The extender contributes a very small amount of scattering in the oiled film. In any case the difference is small and possibly within experimental error. Table IIB and Chart 2 show results at 65 PVC with two vehicles. Again the Sy, values parallel and are slightly higher than TIO2 without extender but the gloss vehicle which gave a marked Increase in Sw for T102 alone gives nearly identical values in these flats except for a definite decrease in Sx 0/D at the highest T102 with the flat vehicle. These films are all above the CPVC where part of the Ti02 is not wetted even by the gloss vehicle. Chart 3 and Table IIB show the expected higher gloss and with the gloss vehicle. The PVC curve on this chart shows the packing relationship of the extender and Ti02 assuming that both pack to 50$ voids, A sharp break In this curve is observed at 30 PVC and a break upwards in the gloss curves Is seen at the same point. At DUP030000011 FOE COMPANY USE ONLY -9~ WP-ESI-66-5 40 PVC free T102, the volume of Ti02 plus the voids between the TI02 particles exceeds the void volume between the extender particles and the spacing of the extender would increase and result in higher gloss. A better than 50# packing for the extender or a poorer packing for the TiOs would account for the break at 30 PVC free T102- 3. Constant (30 PVC) Free TiO? PVC. Total PVC Varied From 45-75 With Each of Five Extender Particle Sizes Table III gives weight and volume information on films. Table IV characterizes the extenders. Table V gives measurements on films. Photos 1, 2, and 3 show the extenders at 1100X. (a) Sw Oiled (Chart 4) From Chart 1, the Sw at 30 PVC free Ti02 is 2.14. With Camel-White a value of about 2.22 is observed on Chart 2 up to 65 PVC. Reasons for this slightly higher value are given in G-2 above. These data are for single determinations and the accuracy seems to be about + 0.05 Sw units. The % oiled (except for D) remains fairly constant up to about 65 PVC which is near the CPVC for these calcium carbonates. The decrease in Sw with increase in extender size is thought to be due to the window effect (see glossary). Part of the minor variations observed may be caused by factors discussed in G-2. A quantitative examination of the window effect is treated separately in this report. Table VI gives the decrease In scattering due to window effect as a # of the value obtained with the finest extender. DUP030000012 FOR COMPANY USE ONLY - 10 - WP-ESI-66-5 Above 65 PVC, Sw increases most rapidly with the finest extender and less rapidly for coarser extenders while the largest extender shows a continuous decrease from 45 to 75 PVC, This sharp rise at high PVC with fine extenders is explained by the fact that the films now contain air voids and the TIO2 is in effect dispersed in a mixture of vehicle and oiling agent (Nujol), the free T102 PVC in effect being lowered and the Sw therefore increasing. Consider seA at 75 PVC. This film contains 14$ air voids reducing the effective free Ti02 PVC from 30 to 20,3 which from Chart 1 would have a 2,8 Sw compared to the actual 2.73. This effect decreases with increasing particle size because the air void size also increases and rather than dispersing the Ti02 the air voids start to act as windows in the same manner as the large transparent extender particles, (b) Sw Dry (Chart 5) At the CPVC a sharp increase in Sw results from the forma tion of Ti02-air interface. The break points on these curves are: E at 60 PVC; A, B, & C at 65 PVC; D at 7 PVC. Below these points small variation from Sw oiled are due to a slight amount of film porosity before the definite break and also to experimental errors. Above the CPVC both dry hiding and % voids (Chart 7) increase rapidly. It is also noted that the rate of Increase of dry hiding is greater the smaller the extender particle size. Steig (4) observed this rate increase and also found that the greater percentage of prime pigment present, the greater the rate of hiding power increase. He found DUP03000001 3 FOR COMPANY USE ONLY - ii - WP-BSI-66-5 a straight line relationship between dry hiding and the "porosity index" which is defined as the ratio of air voids to the total of vehicle plus air voids. In this report, $ voids means $ of air voids in the total volume of dry film, Steig's index is calculated from the PVC and the CPVC, but the latter is difficult to determine accu rately on the actual film. One method is to measure the cake volume of the filtered paint. Oil absorption tests are only a rough guide. Sharp changes in the hiding power and gloss curves are also a guide. In this report, <2.rect measurement of open pore air voids was made. The object of the game is to obtain dry hiding without increasing porosity or adversely affecting gloss and other proper ties, The following table shows how the various extenders perform. Extender (Table III) Paint PVC CPVC (by dry Sw Inflec.) APVC Sw Dry Sw Oil ASw $ Voids ASW x 100/$ Voids Sw dry x 100/$ Voids Gloss-850 A 75 65? 10 4.43 2.73 1.70 13.7 12.4 32.4 20,9 B 75 65 10 3-16 2 .26 .90 11,4 7.9 27-7 7-0 C 75 65 10 3.04 1.99 1.05 15.4 6.8 19.7 5-8 D 75 70 5 2.21 1,58 .63 14.4 4.4 15.3 4.4 E 75 60 15 4.27 2.65 1,62 27*8 5-9 15-3 5.0 It can be seen that the best hiding/void ratio is obtained with the finest extender, but this Is at the expense of 85 gloss. Increased stain retention and poorer scrub resistance. Addition of celite decreases gloss but increases voids drastically. Additions discussion of the balancing of properties will be found in later sections. DUP030000014 a .! FOR COMPANY USE ONLY - 12 - WP-ESI-66-5 (c) Sj m-T-| Oiled (Chart 6) This demonstrates the obvious; at a constant free T102 PVC and constant dry film thickness hiding power drops continuously with increasing PVC since the extender volume is increasing and the volume of TiOg is decreasing. m (d) Si mil Dry (Chart 7) This shows that at constant free Ti02 PVC the increase in dry hiding obtained by raising the PVC is counteracted by the de creased TiOg so that an advantage results only with the finest extender. The results are the same when celite is added to decrease ! I the gloss and, as was shown in G-3-b, celite increases film voids drastically. The general coincidence of curves B & C in spite of the appreciable size difference appears to be related to a better packing for B as shown by decreased $ voids although the given particle size distribution yields no clue to explain a better packing. (e) 0/D (Chart 8) High values are subject to an error of +5$.. This ratio is commonly used as a rough measure of film integrity. Pew commercial paints have a value below 70$. (f) $ Voids-Actual (Chart 9) It can be seen that the $ voids are similar for the smalles and largest extender. B extender (Camel Tex) shows the best packing while the celite is very poor due to its irregular shape. Poor packing means that the CPVC is decreased. ',,'JI DUP030000015 FOR COMPANY USE ONLY - 13 - WP-ESI-66-5 (g). $ Voids-Calculated (Chart 10) A family of curves is given showing the $ voids-PVC rela tion if it is assumed that the total pigment packs to percentages from 40 to 65$ of the theoretical maximum. It can he seen that the actual curves closely parallel the calculated curves. Maximum packing values are accurately determined by this chart. (h) $ Voids for Various Extender Packings (Chart 11) In this chart the voids have been calculated for 30 PVC 1162 paints assuming that the TIO2 plus vehicle phase behaves as pure vehicle. This is perhaps more informative than chart 10. Under these circumstances the A extender shows near zero voids at 65 PVC paint (50 PVC extender) and the extender packing appears to be 50$. At 75 PVC paint the actual voids correspond to 55$ extender packing. This might be expected because capillary forces could be greater in the more porous high PVC films. However, chart 10 shows that the combined extender and Ti02 maintain a constant packing. This can be rationalized by noting that the ratios of extender to TiOs volumes are 1.85 at 55 PVC and 6.0 at 75 PVC. A,large volume of Ti02 at the low PVC packs between the extender voids and compen sates for the poorer packing of the extender. (i) Gloss-600 & 85 (Charts 12 & 13) These have been plotted on a log chart to show small differences at low gloss values. Incidentally, it is noted that the curves are nearly straight lines on either side of the CPVC. DUP030000016 FOB. COMPANY USE ONLY - 14 WP-ESI-66-5 The most Interesting observation is that the gloss actually increases slightly above the CPVC. This is probably due to expansion of the Ti02-vehicle phase by air which would tend to decrease the depth of the valley between protruding large extender particles. H. DETAILED EVALUATION Section G covered the basic properties. Certain signifi cant end use tests are more laborious and less exact. Some of these, but not all (see E-2), have been made on four formulations as shown in Table VII. These were repeat paints. The results are summarized as follows (see photos 4 & 5): 1. Scrub Resistance is proportional to the Sx 0/D as expected because this ratio is a measure of the completeness of pigment coverage by the binder. 2. Resistance to soluble stains is least for the fine extenders presumably because of the finer pore size and greater capillarity. Pore volume does not dominate. 3. Resistance to removal of oily, pigmented stains by wiping is least for large particle size extenders. In all cases these require a detergent fluid and a coarse scrubbing brush or cloth for satisfactory removal. 4. Gloss increase on rubbing is greatest with the fine extender even with celite added to decrease the initial gloss. If one attempts bo reduce the poor integrity of the celite dulled film by reducing the PVC, much of the 1 mil dry hiding DUP030000017 FOR COMPANY USE ONLY - 15 - WP-ESI-66-5 advantage is lost and the disadvantage of higher porosity and smaller pores persists down to 50-55 PVC. At this point, the 1 mil hiding advantage is regained hut the cost increases sharply due to higher Ti02 end dry hinder content. For these and other reasons the general practice is to compromise cost and each aspect of performance. The formulation then "becomes more complex. An example of such compromise is given in the next section. I. SAMPLE FORMULATION The label analysis of a high quality commercial flat "enamel" gave the following composition in terms of volume percent of a dry film. Total PVC Binder CaC03 CaS04 * Si02 ** Ti02 "Free" Ti02 PVC - 59-3 - 40.8 - 27.4 - 3-46 - 8.10 - 20.35 - 33-2 * Fine particle size extender ~2j j , or less. ** Presumably a dlatomaeeous earth-like Celite. The charts were examined and two formulations were chosen to yield average properties that would closely duplicate the commercial product. These are shown in Table VIII. The result is very close. Increasing the Ti02 content would bring it even closer to the commercial product. The assumption is made that the averaging would be correct within the accuracy of the testing methods. DUP030000018 FOR COMPANY USE ONLY - 16 - WP-ESI-66-5 J. VEHICLES 1. Flat Vehicle - Contains 0.264 cc solids (1.05 Sp.Gr.) per cc of vehicle. ADM 302$-p-4o * 380 gs. Naptha - 70 cc Drier Mix* - 16.3 cc * 24^ Pb - 8.1 gms 6% Co - 3.25 gms Antiskin Agent - 5.0 gms Naptha - 50.0 gms 2. Gloss Vehicle - Contains 0.413 cc solids (1.05 Sp.Gr.) per cc of vehicle. Aroplaz 2502 Naptha Drier Mix* Soya Lecithin - 550 gms - 126 gms - 7.3 gms ~ 3.0 gms * 24$ Pb - 24.6 gms 6$ Co - 13.2 gms ASA ~ 6.0 gms 3. Red Oil for $ voids determination. 100 cc Nujol 4 cc 3-in-l lubricating oil 0.1 gm oil soluble red A dye K. METHODS 1. Paint Formulation is calculated on the basis of 100 cc of dry paint film solids. From these the volume of vehicle and grans of pigments required for 13 cc of paint are calculated. Significant volume relationships and the specific gravity and wt.$ TiOg in the dry film are tabulated. 2. Paint Preparation. The required ingredients are measurei Into a glass vial about 2.5" high x 1 1/8" diam. with an internal volume of 35 cc and roughly mixed with a stainless spatula and DUP030000019 FOR COMPANY USE ONLY - 17 - WP-ESI-66-5 additional naptha added to obtain a normal paint consistency. Ten cc of 4 mm Pyrex beads are added and the vials closed with a flat polyethylene cap. Two vials are clamped in a Spex Industries Model 8000 mill and shaken for 10 min. Enamels are mixed for 30 minutes. 3. Film Application. Films are applied to a Morest hiding power chart form 09 using a 4 or 6 mil clearance x 3 inch wide Bird applicator and a Gardna* mechanical drive. A Bird applicator with 6 mil clearance and 1 1/2 inches width is used by hand to make two drawdowns on a sheet of 2 mil Mylar 5 3/4" x 10". in general, the test accuracy is such that only a 4 mil film on paper and one of the 6 mil films on Mylar is required. These are dried on a horizon tal position in the laboratory without controlled temperature or humidity. Drying can be accelerated as discussed in the report and in certain cases drastically affects the results. 4. Film Measurements. fa) Scattering Values. Reflectance on the hiding power chart is measured with a Gardner automatic refleetometer over the two black and two white areas. A brass tem plate 1 3/8" x 2 3/4" and a knife is used to cut out a piece of the lower white section (between the two blacks). This has an area of 25 cm2. A coating of Nujol is brushed on the remaining film and allowed to penetrate for 30 minutes. Reflectance is measured on the top white and two black sections. Reflectances are averaged giving Ro & Rw, Sx values are read from the curves in Ross1 report PTW-8-2-64. A reading of the reflectance of the white portion of DUP030000020 FOR COMPANY USE ONLY - 18 - WP-ESI-66-5 the card is made once for each series. The white cut out is weighed, the paint and lacquer is stripped with acetone, and the paper dried at room temperature for 10 minutes and weighed again. The card lacquer weight is also determined by removal with acetone and then the paint weight calculated. When a new vehicle batch is used the paint removed is ashed and $ TiOg is determined and checked against the calculated value. Sw = Sx x 3 gs paint x wt. T102 in' dry film 1 mil Sx x Sp, Gr. of paint film x 0. gm paint 5. fs> Voids and Gloss - (a) $ Voids. A rectangular piece is cut from the drawdown on Mylar using the same template. This is weighed and then painted with red oil (J-3) and allowed to stand for 1/2 hr. The excess oil is removed'with a flat rubber squeegee. The surface is wiped to a uniform sheen using the forefinger and repeatedly wiping the finger on filter paper. The underside is wiped clean with filter paper and the specimen weighed. The film and oil are removed with acetone and the Mylar weighed. Tie weight of paint and absorbed oil are calculated. The volume of voids = gms oil absorbed * 0.882 = cc oil. fo Voids = cc oil_________________ x 2.00 gms paint/Sp.Gr. paint + cc oil This test is most accurate when a blank is run on a nonporous film having about the same degree of surface roughness since the wiping DU P030000021 FOR COMPANY USE ONLY - 19 - WP-ESI-66-5 leaves a small amount of surface oil behind the Irregularities. It has been found to be more reliable than measurements with a dial micrometer because in the thickness measurement the film is com pressed, weighing Is more sensitive than the dial which must be estimated below 0.1 mil, the area measured by the dial is a small proportion of the whole. Roughness probably results in a greater error with thickness measurement than the weighing . (b) Gloss. 60 and 85 gloss were measured on the Mylar before the void determination. L. DISCUSSION OF WINDOW EFFECT W. D, Ross has considered the theoretical aspects of the window effect and proposed the equation F = 3/2 + 2 PSD where F is the ratio by which the apparent scattering of the paint surrounding the extender is lowered, P is the volume fraction of extender in the film, D is the extender diameter in microns, and S Is the scattering in reciprocal microns of the paint surrounding the extender. Accord ing to chart 1, at 30 PVC Ti02 is 2.14 making S (Ross) hlH = 12 0.178. S-j_ mil for the TiOg alone is 5-72, then Sw == 2.14F and S1 mil " 5.72 x F x (1-P). PVC F 2(i 10(1 Calculated Actual 2(1 10(1 2|i 10(1 2(1 10(i 2(i lOjl sw Si mil s.w slmil 45 952 ,798 2.04 1.71 4.34 3-64 2.21 1.99 4.62 4.16 50 .937 .745 2.01 i.59 3.82 3.03 2.15 1.88 4.10 3.57 55 922 .702 1-97 1.50 3-39 2.58 2.26 1.85 3.87 3.17 60 907 .650 1.94 1.41 2.96 2.15 2.24 1.71 3,39 2,59 65 .894 .627 1.91 1.34 2.56 1.79 2.24 1.70 2.98 2.26 70 .880 595 1.89 1.27 2.16 1.46 2.46 1.65 2.82 1.88 75 .867 .557 1.86 1.21 1.77 1.16 2.73 1.58 2.60 1.51 DUP030000022 FOR COMPANY USE ONLY - 20 WP-ESI-66-5 These calculated values for 2\i extender show only a slight continuous decrease in Sw. The actual increase has been explained in this report as due to expansion of the film with increased PVC and conse quent effective decrease of the Ti02 PVC. The Sw calculated for the lOp, extender is uniformly about 0.3 unit too low and the calculated S1 rail value .for 10|x is about 0.45 unit low. If 0.6 unit is added to the calculated S-^ and the Sw calculated from this, the values increase above 55 PVC for the 2|i extender and show good agreement with the actual results. At 65 PVC and 30 PVC free TiOg the dependence of Sw on particle size of the extender is accurately given by the empirical equations: 1 d 1/3 + 2 and Sw = F x Sw(2) where D is the extender diameter in microns and Is the determined value for a 2 micron extender particle. D P Sw Calc. Actual Act.-Calc 2 4 7.5 10 30 40 1.0 0.905 0.820 0.785 0.640 0.603 2.24 2.02 1.84 1.7.6 1.44 1.35 2.24 2.00 1.93 1.70 1.56 1.32 0.0 - .02 + .07 - .06 - .12 + .03 The 30 and 40 micron paints were made with Plex-O-Lite glass beads. Other properties of these paints were: DUP030000023 FOR COMPANY USE ONLY - 21 - WP-ESI-66-5 30d 40|j. Sw -- oil Sw - dry fl mil " 011 I Si' ^ Gloss - 60 Gloss - 85 $ Voids REFERENCES 1.56 1.62 2.13 2.22 96.5 3-4 2.4 12 1.32 1.52 1,80 2.08 86.0 3.4 2.3 14.T (l) 0, E. Paukner, Fundamentals of Formulating Flat Finishes, Paint Industry, Feb, (1962), (2) T. C. Patton, Paint Flow & Pigment Dispersion, Wiley (1964). (3) F. B. Steig, Jr., Official Digest Federation of Societies for Paint Technology, June 1959. (4) F, B. Steig, Jr., Official Digest Federation of Societies for Paint Technology, July 196I. DUP030000024 TABLE I .TlOo ONLY PVC-R-900 Wt. % TiOp In Film Sp.Gr. Film SW - .004" SW - .006" SW - Av. S-l mil-.004" S-l mil-.006" 10 30.7 1.37 3.43 3.75 3.59 3.03 3.31 A - Flat Vehicle 15 20 41.4 1.52 3.18 3.22 3.20 50.0 1,68 2.74 2.81 2,78 4.23 4.85 4.28 4.98 25 57.1 1.84 2.36 2.69 2.53 5.24 5,65 30 35 63.2 2.00 2.11 . 2.19 2.15 68.2 2.15 1.87 1.85 1.86 5.61 5.84 5.79 5.73 40 72,7 2.31 1.58 1.47 1.53 5.59 5.23 SW - .004" SW - .006" SW - Av. B - Gloss Vehicle 4.06 3.59 3.21 3,65 3.44 2.98 3.86 3.52 3.10 2.81 2.82 2.82 SW - .004" SW - .006" 0 - Flat Vehicle 2.77 2.00 Room Temperature Dry 2.71 2.57 2.19 2.07 1.98 1,95 DUP030000025 Free TiO? PVC T102 PVC Extender PVC Vt.% Ti02 in Pigment Wt.,55 Ti02 in Film Sp. Gr. of Film Plat Vehicle Oiled SW - .004" Oiled SW - .006" Oiled SW - Av. SW Enamel-Table IA Sx O/D TABLE II CONSTANT PVC EXTENDED PAINTS VARIABLE FREE TlQg PVC 10 15 20 25 3.9 6l.l 8.85 7,35 2.18 6.17 58.83 14,0 11.7 2.22 8.75 56.25 19,5 16.3 2.26 11.65 53-35 25.4 21.3 2.30 A - 60 PVC, R-900, Camel White Rapid Dry _________ 3.59 3,43 3.55 3.49 3.20 91.0 2.86 2.78 2.82 2.78 92.3 2.64 2.55 2,61 2.53 94.2 30 15.0 50.0 31.8 26.8 2.35 2.26 2.32 2.29 2.15 98.5 35 18.85 46.15 38.9 32.9 2.41 1.86 40 23.3 41.7 46 s5 39.6 2.47 1.53 Flat Vehicle Oiled SW - .004 S1 mil Sx 0/5 % Voids Gloss - 60 Gloss - 85 Gloss Vehicle Oiled SW - .004" li m % Voids Gloss - 60 Gloss - 85 Enamel-Table IA B - 65 PVC, R-900, Camel White Room Temperature Dry 4.17 1.41 85.8 5.3 4.4 12,9 3.32 1,82 88.8 4.1 4.5 12.9 3.08 2.39 88.5 5.0 5.0 13.3 2.58 2.70 89.8 4.0 5.4 15.1 2.40 3.20 88.8 6.1 5.7 16.4 I.94 3.24 88.8 2.7 6.8 20.3 1.76 3.62 83.O 4.4 8.1 25.9 3.84 1.30 87.0 3.5 4.9 22.2 3,40 1.86 92.7 2.7 5.3 18.9 3.86 2.96 2.30 90.0 3.0 5.4 20.7 3.52 2.56 2,65 90.3 3.2 6.5 22.0 '3.10 2.27 3.70 88.0 2.0 6.7 23.5 2.82 2.06 3.45 88.8 1.7 8.4 25.1 1.84 3.79 90.0 2.7 9.4 32.6 DUP030000026 P LA T P A IN T S PVC EXTENDER S IZ E V A R IA T IO N Sas Cam el W h ite Camel Tex Cam el C arb #10 W h ite 7555 Camel W h ite , 25% C e lite 2 8 l as mo m mom h c m c m co ma- -=r .* c m c m c m c m. c m c m c m CM f-HVO 0 >=J- CO H h c m c m co co co <i CM CM CM CM CM CM CM Wt OCMOHm PHBC 3B H H t'"V0 CM 00 O VO cdmifvco rtvo h vo m-=T coco c m c m o c^- m H vo cp c m CO-ST VO ON CM VO H SO m^ CO CO CM CM iHE OCMfHc 3P=E* ' rlOH CMOOVOar ** vo Hvo H VO CM CO sr.sr mm Cm c m h o mvo co J3- h o\ VO HVO H f-COOO ST ST CO (TV.CM CM H p Oh r> r--i Pi CD o ii ii i i ii iiii O ,H rl rl H rH H k o co o c v j -=r vo co i--l ri rH rH rH CO 0.0 !> o Ph o j=r vo t- p> o H co **** h co m c m cp t---=r c m c m c o j t mmvo sr m vo co ov o c m ** m o in in h vo H CM CM COPO-ST ST VOr CO H O Ovt- c o h pv c-mcM O CM CM H rl rt H H VO-Sf CO HVO CN t- COH C3VC-mCM o CM CM H H H H H. s a> 05 p #1 o CP CO P CD t I I II #00 < CQ O Q Id OOOOOOO CO CO CO CO CO COCO OO O Oo o o co co co ro co co co ocP t> h CU eRul momomom *r mmvovo t>c- tnomomom ar mmvovo t-c~ p c H% aC*tt H CM CO . mvo t-~ COJ3- mvo c-co ON CO CO CO CO CO CO CO *op % I * CO I Id DUP030000027 Extender Info Prom Suoolier ASTM SSD <y diam.) Coarseness Distribution % Finer than y Oil Absorption Our Testing Specific Surface m2/g Median 0 by wt, from microscope TABLE IV EXTENDER PROPERTIES Camel White Camel Tex Camel Carb 2.0 4.0 7.5 10 30 44 100-15 98-10 72-5 40-2 15 99-30 92-20 86-15 76-10 54-5 28-2 14 99.5-44 97-40 89-30 78-20 70-15 58-10 40-5 19-2 13 3.1 2.3 2.1 #10 White 5+ 44 99-40 86-30 68-20 40-10 26-6 20-4 l4-2 7-9 <1 10.0 Celite #281 2 to 12 y 2.0 DUP030000028 ALKYD FLAT SERIES (1 ) Added to 13 cc g rin d s to g iv e about the same consistency f o r a p p lic a tio n > a t ar ar ar in m h 4 * O' OOOOOHfll -a*tnax\o * * OOHH _ ararvo eg in *.* OOOHH mar pv oo . o OOH H in moo eg b-ar m * o . h h eg m vo eg o r-- in t-ar cgooHcgencncv H b-H megoar m oopHmmH rH nonnfoco^co >ar b- bar eg eg mmvo h u v n . eoHmmvo * bl HH H rH ar m mar co <Sv *< mb-ar H b-m negeg ar ar Q tXo \o co f-i^-AT .in fi^ OCO O mvo mHVO 0 0)00)00 b-VO 9) HH b-e-cacocgr-iin OCOTTMIAHO OyPV C\ <7vOvCO b- rH in <g vo h oo eg vo m eg mar ar co vom b-b-inarvo b-in o . in b-ar co oo m h vo ovov ovoo cp b-vo o ovov ovooooco b- pv H inegar o\o * . eg mar vo rH co eg o p v e?v ov co vo vo o H rH cu co eg in b-ar ar in m o vo H co \p ar co eg ar ar ar mmmmar tn m ovmcopvco t*cO m b-vo moo co pvm ar mm meg eg eg in N- b-oo m in coeg- b- b-vo mvo ar H pv eg in in m p pvoo oo mvo mov in eg h vo ar mmmeg eg eg in vr mmeg eg.eg eg in vo vo eg b-co ovvo ar ^ eg vo b-CO ar aaam mmar vo b- m * UY <M O b OvCO (VJO CM VO r-fOO movcovo CM ar ar m m eg eg eg in -i ar ar vo in in oo eg .t-ar egvoar rH m r mmmeg eg eg in vo i-*cg vo ar ov cg Hararcoinegcooo ar mmeg eg eg h in vo b- b- CVVO CO rH bHinHincy mar jrmmegcgH rH in vo b- pv ^ vo e* eg ar in b- in vo mar ar ar mmmev egvo b- ar in rH CO VO H CO in fO CM <\J rH CViar Ifim 44*4444 <y w <M w eg mar eg . ovcg moo eg vo eg OV H egrH in rH O eg ri eg <g o j eg m c j ar oo ov eg o ar cp ooo o eg eg in h eg h eg eg eg eg meg ovvovo mmvo h m pvovpvovpv rg h (v j h h h h h egig b-^r vo maa* ri b- eg H eg mar co ar eg eg eg eg eg eg mar eg VOO eg rH invoar ar vo mvo eg h eg eg eg.ar b* Pv N eg N w eg eg *g H r-i r-- rH Hoar VO <\l ov h H eg eg h eg evi eg eg eg eg ov m in mvo ovco P>CO CO Ox Ov ON rH rtrlWrtHrtrtW OVCO in rH O in CO US OVCO CO b- b-vo in o H H H H H H H eg egaregmbarmeg eg H eg m m mvo ar eg eg eg eg eg eg cvi eg oin eg megOVOVOCgarovpvmayenmovm vo ON<MruraniAHOO^SmiA b~ CM *rVO aT eg H H H <\) PV ov*^ b~H cg so Pvmb-rvovob-m 4A04 H 0% **. mar h co vo ** PV ** | h co in m b- h in <* co vo in mar arinin CM C\ o m ON \oif><MHOOO\o Pv mmb-vovovpco mfg-H oo wa*N^(^cotnH > * S 4* * 4 vo ovovoarar moo roHH co o O ar meg pvVO . egb-ovo miArno fOr*4 H V NKO mmo binco v ar m in I fOH H HmvOb-CO <\JA! 4 4 4 .A 4 .4 ov infom^f .H r I '' , 00 0O k CO p>o* *hcco amrinoimnvoo vmo bo-mb-mo m*r mominvooivnoob-ibn-om ianr owimnvoomvoobtwnbm tnr motinnvoovinoobu- bv-om iahr oinmmvooivAoobm- b-m m a* ... Id h c mirtvo s d o\o Hn <*V ir\us .HHHHHHH d NoovonNuw HHH<M<M<M<VN - d lAuNgono h N N N N N nTHm -o >. ia s o t-< o \c j <n<nf0<A<r< <><* ) .* > a! ' +p> P *'' w (SC H P oS pX CO fcl H P o I0 iH <D o1 o +> H H CO w d eg HO *3 P EH O58 0inU u 2 p ooC o DUP030000029 <D + *PH <D tSS, P H rH r--I Q) a> H o o w in rH O CD m CO in p~ OO o ON ON rH rH rH rH IEdh H 3t' 4 Id 2< Id O E> > CO Id MG t> Id K Id >3 W; Q EChO 03 Id E<H W 13 SB Wto Id to 1h O Eh OO Itdo Id id to M w. o Ss co to o w a> p H x: 3= a o srHtt; XI Cl cd o o a> o X E<hu 41 03 E M Q <U -U |H. X! 3: <s 4) O in o p- <u ON CO CO in ? vp-id f* <6 p* N \o m in in in . * o on icno ccoo ccom ncoo oi--n ot-n in rH rH ON -ST ON ON CO ON in : ON P^ CO CO CO 00 o OOOOO o , ' O o O O rH. rH rH rH rH rH rH "sfc P ti <D CO Ta5> C> 0) P X Id r<HD OS Eh o in o in o t>o r in in n o P C H tod in o in no p~ p- DUP030000030 EVALUATION OF 70 PYC PAINTS *Red m arking crayon. Black M arks-A-Lot In k . '^W eighted brush o o OO Cx3 CO S= O' o p OO co X> Jh <3 a CM CM 0) o M3 < o p P sz s O o O mt>- ON CO p t-- inCVJ -qj* VO o n O COCO >-- o ro N-VD c-- CO t--p in eo us <v> c mc o c m cot'-sr c m Par invo-^'H Osqr j t vo c m cm p m on 3-HSP <n-=r vo co vo cv oo r c m us . CVI CO CM COOO -W1 CM P-ST q*VO CM CM p CO <3 t--ovovo USCO 9HOOH OV POO lf\VO CM VO O CQ vo-sr c m o ar cn p P OO ST r **- HHrlPI COOO ON CO ITN^T UNOO O JW -SC US H eori P tnvocoqr VO OvCp CM 00 O CM . PPPCMCnONONO CAP- CO P p OONS CmOoCoM VOON O VO ST CM ONNO o Kh h o COCO LTV VcOo--iCncr-oi CQ P c m c m c m us <o vo-qf-sr c- c m c m c o c o v o .p o OO P I--I JC {* vo o -=r o as in c m os c m c m qr co c m p 1 H c m c m c m o-vo -=r p inus C-- H rt 03 qr c o c s c m qr o t-mmqr usoso cocococo P VO o VO o COC-rl g COVO CvIM-* c m co c m oo o n C- c m qr vo qr c m c o \o as in os P pqr (MOO H CM VO US CM US < iq- coco 00 ST US US o o US CM CO CM CO CO rH CM OSVO tf~ P"*,rH P (3 C o a o c P t3 E o * CQ O > ? o JO CO (3 CM qr m p (3 fat) Ml PC <M 43 0 to P mp oo cc cu o oo vo o^r HlPN o p o p Ei* O o p J3 o o to ON CO p VO Cn H co p x: o o to oo inn =ra>H CQ r-1 <3 MO rl P US P b (3 CM Mfc p CP P a> (3 CQ CM U o xt c <u p X w o <u H Ml Oo 0in vo 00 o 05 p0 CIO H O0 c3 to + M --- TJ M P CO oo >P P >s P iM cu O XS 0 O OQ p ojoinB to p p mo co o P to P PC5 3 0 0 P p Sh p P"V p O OJ CO to to POO E EO P f* to to p X > M5 O OP <0 'St S: P P X O O P P O Eh CQCQCQCQCQMUOeOCM o in CM CO O O 0 vo co O Ch 3 o us . p ,j a> to voco . O c 2 3 <? bO 0) 0) o w IM a P p e o po p U V. bD C 5 o <3 o 0) P <3 P =tfc O W CC CM P (3 P P lA O P 1 1 to 3 .^ O tO X O. a c OOP 3 CB o p P O 3 ti o p <3 P P O O O CQ o O O CO OS CQ O O oe e o P Jh 1 PP3 >s cti (3 P t-i P M M M tB 3 tn M M POO CQ g * H< P xqsp <3 OS 03 Pm PS < DUP030000031 Extender PVC PVC Free T102 Gloss * 60 - 85 SW - Oil SW - Dry S1 mil 011 Si mil Dry Sx O/D % Voids TABLE VIII MATCH OP COMMERCIAL PLAT Commercial Plat #36 Camel White + Celite 59.3 55 33.2 30 4,1 5.6 \ 6:2 5.3 2.13 2.22 2.54 2.36 3.18 3.79 3.81 4,02 83.8 94.2 7.8 .. . 3.5 : #14 Camel Tex 70 30 4.8 6.2 2.14 2.52 2.45 2.88 . 85.1 5.0 Av. #14 #36 62.5 30 5.2 5.7 2.18 2.44 3.12 3-45 89.6 4.3 DUP030000032 DUP030000033 (2) R- 90Qt Came[Wh,'fe '*hi Pi/cfrec 77^ hi. X S / /rtt '/ DUP030000034 h 'JOl Ci-l BjQ_ 7-C- *V: : r': R-qOO r Came I Prc ft** r,a /s. c -/0j s jEtfref i< 77S?j, PacPt fig /]// 6\r PtsC (3j DUP030000035 DUP030000036 i m* .^ ' ntm f Pl/c Pi ' f . 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