Document vBNDRgxMqG7rBy0z2DQ4Kwg16

H. VAN LOO Cont. #97 - Pont, To continue the previous series of comparisons of the relative durabilities of various changes in S'TP Gloss YJhite since 1935, panels on the last seven revisions were, prepared for exposxire at Chicago# Paints were prepared for exposure of the new Family Paint IVhite using higher percentages of lithopone and leaded zinc with mica added, con serving Titanox EC* Exposures of Barn Red after 18 months in Florida show no significant differences with various first coat reductions employing raw linseed oil, boiled oil, or PM oil compared with two ooats of Hex 54 full body, or the two coat system of Commonwealth Barn Red Primer and Eex 54 top ccat. The most important factor seems to be film thickness. Other exposures of Earn P.ed after 12; months in Florida show no significant difference between aoicular zinc oxide and American zinc oxide 108 N additions. . Comparative grinding tests were made of recent TiOz production vs. 1403 T using the titanium oxides as the sole pigments in an SWF vehicle. The Ti02 is more difficult to grind on a roller mill, has irnoh lower consistency characteristics,' but initial drying was satisfactory, , The samples will be examined after a. period of storage to determine relative tendencies toward absorption of drier, #86 -Durability of Pigments with Special Reference to Leaded Zinc and 7/hite Lead Considerable time was spent during the month on the development of a lead-zinc exterior paint based on 414 ?F. Using varying proportions of 414 '7 and lead carbonate, the zinc oxide content varied from 34$ to 46.5$. Check--" ing tendencies are at least partially counteracted by' the use of inerts, including mica, and p.v.c. at approximately 29$. Brightness is reduced. Exposures were prepared for Chicago ana Goffeyville. To prepare for any poss'ible shortage of basic carbonate white lead a series of special paints have been prepared for exposure using 40 pounds of Ti02, and in one" series 200 pounds F.Y 102 and in the second series no carbon ate. In each group the only other opaque pigment is successively 414 W, 412, and 1526 dry. Using the lead carbonate the zinc oxide contents are 48$, 39$, and 34$ respectively. "Yith no lead, carbonate the zino oxide contents are 58$, 44$, and 41$, respectively. Mica was used to reduce checking tendencies. Brightness and hiding are be lev; S'T? standards. Considerable improvement has been made in the color of 414 dry dur ing the month. 414 '7 is the number now assigned to the. cleaner, brighter pigment, which will be used in S7/p tints and other formulas. A standard sample for 414 Vi.was distributed but subsequent production has shewn a still further improvement in color which considerably expands the possible scope of usaee. All plants are asked to make all possible use of this pigment. 0007-SWP-000006874 K. VAN LOO Cont #86 - Cout Texture determinations were made on two samples each of 414 V?, 1526-dry, and 412 dry, and grinding rates ware determined using the standard ized procedure, comparing 1526 dry and 414 W at equal poundage in an SPJP tint base formula. The results were Texture Paste Consistency Grind Production/] 414 W Std. 414 W Lot 183-3 1526 Lot 3591 1526 Lot 42 412 Lot 116 412 Lot 3581 6 6 6-3/4 6 6-3/4 6-5/8 S.2 sec. 7.6 " 11.2 " 12.2 " Not run Not run 4. 172 grams 4 169 " 4 188 " 4 154 M --' ' #12 - Exterior Primers Opacity brush-cuts of Rex 450 SWF Underccater showed definitely superior hiding power over Devos's Cnderooater. Therefore the opacity of Rex 450 was reduced 10% by adopting a formula carrying 55 pounds TiQ2, with 18% zinc oxide introduced as 414 W. Hiding remains better than Devoe's, Ward's, and Moore's primers, but under Sears' and Pittsburgh's primers. Anticipating the necessity for eliminating (2281) from Rex 450 because of shortages of oiticica oil, experimental formulas were prepared sub stituting V 17005 and (213) respectively. Regular Rex 450 set to touch in 6 hours, with replacement by (213) it set in 8 hours, while with 4 gallons of V 17005 the set to touch time was 6-1/2 - 7 hours and with 6 gallons of V 17005 about equal to regular formula. V 17014 gives too heavy body. The over night dry was satisfactory for all, with the (213) underooater slightly s oft In further studies of crawling, earlier tests were duplicated, and again the experimental Rex 450 formulas at higher p.v.o. were free from crawl ing when recoated with SVP Trimbrite reduced 5095 with linseed oil. Further work is under way using the recent Rex 450 at 36.5%, 40%, and 42% p.v.c. Sanding the dried 450 film, eliminated crawling, as did the addition of a quarter pint of a 33% solution of Aerosol O.S. in alcohol to the gal lon of top coat. The addition of a quarter pint of anhydrous alcohol also stopped crawling, but the evaporation produced an orange.peel effect. There is also indication that the S'.7P Trimbrite formula with 15 gallons of (2281) did not crawl. 0007-SWP-000006875 -6- K. VAN LOO Conte #148 - Examination of Vfoite Lead, The January, 1942 Analytical 5d.ition of the Journal of Industrial end Engineering Chemistry carries an article on.the preparation of pigment mounts for microscopic examination, by dispersing the pigment in Duoo House hold Cement. This method is essentially the same as that demonstrated to members of this department by a member of the Anaconda Company's /SJhite Lead technical staff. - The pigment is dispersed by rubbing, with a spatula, a small amount of pigment in a drop of the cement on a microscopic slide. For details the original article may be consulted. It is a simple method with considerable merit - it is rapid and the mounts are quite permanent. However, some diffi culty was experienced in obtaining a single layer of pigment particles with the entire field in sharp focus. This is essential for photography or for . particle size measurement. Farther work will be done, and if any entirely successful method is developed, details will be distributed as a report. . #105 - lietal Protective Paints The rolling steel rod tests this month were confined to checking cur results with those obtained by other workers in related fields. Results reported both in this country land in England showed that well orientated rust inhibiting fatty acid monolayers were possible with straight chain fatty acids having at least 6 carbon atoms to the molecule. The following results were obtained t Fatty Ac id Acetic Propionic ' Butyrio ' Valeric Caproic Heptylio Caprylic Laurie Stearic Oleic Control (no acid) Carbon Atoms 2 3 4 5 6 7 ,8 12 18 18 Condition of Steel Rod Bad corrosion It w Bad rust Slight rust Perfect perfect Perfect Perfect Perfect Perfect Bad rust This series again shews that the 6 carbon atom fatty acid is the boundary line for protection. The tests were run at 0.1, 0.05, and 0.01 molar concentrations For stearic acid these corresponded to solutions of S?, l-l/Sjo, and 0.5% as previously reported. For acids longer than caproic there was perfect protection even at 0.01 molar. The reported listed above refers to 0007-SWP-000006876