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c -^ indexed cos W. D Lawsona Lab. R* B. Davisa Lab, MTM TO MARSHALL LABflfiATOfiy LIMY 0, D, H, L, Bullitt, Herndon, S*Pt8ta*WSto* Lab, &. C, Lamport, Lab. C. W, Shay, Lab, Patent Section, Lab. h d s x e iv Library, Lab. (5) Iff $0*54 Files 1810 Marshall Laboratory April 26, 1954 MEMORANDUM REPORT HO. M-TOO PREPARED BY: W, F, SINGLETON COPY COLOR VARIATION 1H BRUSHED F FLOW SOTS" IMODUCTlOHs Dulling the past year, scattered complaints have been received concerning variation In color or depth of color in brushed films of "Flow Kota". The most specific observations ' have been made In Dallas, where it has been reported that Satin Luminal! and possibly other competitive paints are superior to '`Flow Note" in this regard. The phenomenon has been variously reported as "streaking, "shadows" and other terms. The trouble appears to be "floating" of the shading pigments in taedlum and deep tints. This process goes farther in thick films where there is relatively little working by the brush and where the film remains fluid longer. If the paint is not thoroughly brushed out on a wall, the areas at the end of brush strokes and the areas under light brush strokes will be thicker than most of the wall, and floating of the shading pig ment will mate them darker. STOMAHY: A simple and effective method to correct the color variation In most "flow Kote" tints has been demonstrated in the laboratory. Potassium tripolyphosphate Is used as a dis persing agent In the "48 Process" dispersion of titanium oxide and extender. The potassium tripolyphosphate must be .added in the dispersion step? It is not effective when added later. In addition, the shading baa with monastral blue has been revised to improve"the dispersing of the blue pigment in water. w T Enough work has been done in the laboratory to shew that the dispersion of carbon black requires drastic improve ment . This problem remains for further investigation. The chief colors in which it is important are Driftwood Gray and Moss Green. Other organic pigments, toluidine yellow and toluidine red, may require attention, but have not yet been investigated. One thousand gallons each of Aspen Green and Bellflower Blue have been made in the plant on a potassium tripolyphosphate formula. Both are a definite improvement over current production, Neither is as good as laboratory material made on the same form ulae. An obvious further step is to increase the concentration of potassium tripolyphoaphate for plant production, this remains to be tried. ACTION: The Research Laboratory has stopped work on this prob lem because it has been reclassified ss G rather than A research. The leads that have been developed will be taken up by the Sales Development Laboratory. DETAILS: Color Variation in "Plow Kofre" and Competitive Paints: A simple test will demonstrate the degree of pigment floating". The paint is brushed out on a panel In a uniform film; While the fifcm is still wet* paint is flowed over half the panel. After the film dries, the color contrast between the flowed and brushed films is an exaggerated measure of eoler variation. By this test, all the tints in the "Flow Kote" Line except the very lightest ones show a degree of color variation that requires correction. Satin Luminal! has almost no color variation. Contrary to the situation in "Flow Kote", the white pigment tends to "float" in Satin Luminal rather than the shading pigments. Super Kemtone is better than "Flow Kobe" overall, although some Super Kemtone colors show definite color variation. Mechanism of Figment "Floating": Pigment "floating'' is an abnormal result of the cir culation of pigment that always occurs when a film dries by evaporation,, Convection currents tend to carry the pigment to the surface and back through the depth of the film. The ease With which the pigment is carried along depends on the following: DUP030003684 -3- Ultimate particle size Density Breakdown of agglomerates in primary dispersion Flocculation How well the liquid medium wets the dispersed pigment particle. In the production of "Flow Kote", the blend of titan* ium dioxide pigment and clay extender is dispersed in casein solution. The degree of primary dispersion is satisfactory. Casein is a good wetting agent for titanium oxldei a slurry in casein solution will be quite fluid when stirred, while the same concentration of pigment In water alone is a heavy puffy paste. Upon standing, the slurry in casein sets to a reversible gel. The gelation is responsible for much of the color varia tion that occurs in "Flow Kote"j it prevents titanium oxide fsm being carried to the surface of the film, with the result that the shading pigments become more concentrated at the sur face. Potassium Tripolyphosphate to Deflooculate TlOo: Potassium tripolyphosphate is an extremely effective dispersing agent for titanium oxide* The heavy puffy paste with water alone is changed to a thin water suspension by small concentrations of potassium tripolyphosphate, and the pigment settles rapidly from these suspensions. When potassium tripolyphosphate la added to a casein slurry, the slurry remains permanently fluid. Potassium tripolyphosphate corrects the color variation in "Flow Kote" by partially destroying the titanium oxide gel* An optimum concentration of potassium tri polyphosphate roustbbe found$ at low concentrations the shading pigment will still float in preference to titanium oxide, and at concentrations that are too high, the titanium oxide will float in preference to the shading pigment. The optimum con centration Is not very critical, so that one concentration will probably be satisfactory for most colors. Four representative shading pigments were added to "Flow Kote" containing three different concentrations of pot assium tripolyphosphate. The color variation was determined In the fresh paint and also after the paint had been aged one week at 120F. In order to accelerate any changes that-mlght occur. The results are shown In Table I. For three pigments red Iron oxide, pigment green-B and monastral blue - the optlrn* urn concentration Is about 0.2$ potassium Iripolyphospbate on the weight of the total paint. Little change occurs at this con centration when the paint is stored In the oven for one week. Loss of Tinting Strength with Black Shading Pigment: The black, shading pigment now used In "Flow Kote", Aquablak-L, shows loss of tinting strength in the fresh paint with potassium tripolyphosphate. The brushed film Is a normal DUP030003685 ~4~ gray color, although It shows white streaks along the brush arks. The flowed film is almost white In color, forming an extreme contrast with the brushed film. A possible interpret*' tation of this behavior is that the black pigment is much more readily wetted by organic materials than by waters it surrounds itself with particles of latex by a process of flocculation. When the paint Is heated for one week, the pigment becomes much better wetted by the aqueous medium, and the tinting strength Is restored. The problem with this shading pigment therefore is to find a surface active agent or a combination of agents that will disperse the carbon black rapidly to the degree that it becomes dispersed on aging In the oven. Potassium Pplyacrylate as Deflpeculating Agent; Potassium polyacrylate, VM-54TO, can be used in place of potassium trlpolyphosphate to regulate the degree of gelation of titanium oxide In the presence of casein. Paints were made in the laboratory in which color variation was corrected by dispersing? the titanium oxide in a mixture of casein with a minor proportion of potassium polyacrylate. However, potassium polyacrylate precipitates casein. After this discovery was made, the use of VM-5470 was dismissed from consideration. Previous work had shown that the viscosity stability of "Flow note" is poorer with, a blend of casein and potassium polyacrylate than with either alone as thickener. It now appears advisable to eliminate potassium polyacrylate completely from "Flow Kote" in the expectation that the viscosifcy will be more stable. Other Wetting Agents for Titanium Dioxides . Tasjol 731 is not effective in the presence of casein, although It is an effective wetting agent for titanium dioxide by itself. Lustres 820 and Triton 770, agents used in Custom Color 'Flow Kote", are fairly effective wetting agents for tit anium dioxide, but their effect in the presence of casein has not been determined. Soya lecithin and potassium pentachlorophenate {Dowieide), surface agents normally present in "Plow Kote", have little wetting action for titanium dioxide and have no effect in the presence of casein. Monastral Blue Shading Bases Part of the color variation in Bellflower Blue Is caused by the difficulty in wetting Monastral Blue. The latex dispersible pigment -526 that Is used In "Flow Kote" consists of Monastral Blue pigment with about 30$ of Daxad KLS and Lustrex $20 to promote dispersion of the pigment in water. These agents alone are not sufficient. The current mill base, 547-5009 disperses the pigment in Latex, G-f28, and- soya lecithin. This mill base dees not stir Into water readily,' and the pigment is apparently not well wetted. As an Improvement,, a new mill base. DUP030003686 f -5^7-0^7918T has bean formula feed in which -526 is dispersed in glyceryl monorieinoleate, KH-5187* The formula Is given in Table II, The Monastral Blue pigment is diluted with extender in', order to improve the fluidity of the base and tb ease of miss ing it into water. There is an optimum concentration of glycer yl monoricinoleatej at higher concentrations, glyceryl monoricinoleate separates as an organic phase that contains most of the blue pigment. Soya lecithin and pine oil Sr wetting agents for -526, but less effective than glyceryl monO"*icin- , oleate. The hydrophilic agents that are effective with titanium dioxide are not effective with Monastral Blue. Monastral Blue requires an orgenophilic surface agent to wet the pigment in the first place, and a hydrophilic agent to disperse the wetted pigment in water. Besides Based KLS and Lustrex 820 that are present on -526, Triton X-100 is effective as a hydrophilic agent. Plant Trial: 1000 gallons each of Aspen Green, 391-023, and Bell flower Blue, 391-019,have been made in the plant on formulas containing potassium tripolyphosphate and the improved Monastral Blue mill base. The formulas are given as Tables III and IV. Quantitative measurement of the color difference between brushed and flowed films is presented in Table V, The films were measured in the duFont differential colorimeter, and color dif ference was calculated in MBS units from the tables prepared by Brown and Troy. The minimum perceptible color difference is 0.3 MBS units. The plant trial batches are better than laboratory or plant control batches. They are not quite as good as the laboratory batches on the same formula. Plant production may require more potassium tripolyphosphate because the conditions are different while titanium dioxide is being dispersed. Dis solving the potassium tripolypbospbate before it is added to the dispersion mixer might increase its effect as an alternative to raising the concentration. The application properties and film properties of the trial batches are satisfactory, including scrub resistance and stain removal. Viscosity stability may be a problem. The vis cosity drops faster than control batches in an accelerated test at 120F, Elimination of potassium acrylate is one lead toward improving tb viscosity stability. DUP030003687 REFERENCES? -6 Notebook 5771. Notebook 5829, pages 2 through 9. "tables of Color Co-ordinates"? Engineering Research Laboratory Report DED-X-52-22, by J. B, Brown and D. J. Troy. WFSjrolf V23/5^ DUP030003688 : -T- TABLE 1 Color Variation In "Flow Kote" Tints with Potassium Tripolyphosphate Color of Iflowout versus Brushed Film, PIGMENT W-723 Figment Green-B AGING initial POTASSIUM TRIPOLYPHOSPHATE # OF TOTAL PAINT BY WEIGHT ---------- wmr snught No contrast Bark 120F-1 Wk SI.dark Si.gray Dark & Gray W-303 Red, Iron Oxide Initial Light Light Dark 120F-1 Wk No contrast SI.light Dark W-526 Monastral Blue Initial Light No contrast SI.Dark W-231 Aquahlak L 120F 1W&. Initial No contrast No contrast Dark V. Light V. Light V. Light 120F lWk. SI.dark No contrast Dark DUP030003689 -8- TAB1E II Monastral Blue minting Bag;' CODE STATUS H-506 KH-51S7 G-T28 G-729 Water Glyceryl Monoric1noleate Dow latex ?62- W J>. soya lecithin -1002 -526 ASP-400 Clay Monastral Blue, L.D. H-506 Process P-547-D-79187 Improved 36.2' 10.5 * 547-5009 Current - 652 42.8 10,5 15 mm 18 100.0 3-roll* 100 3-roll** "48 Process" satisfactory In laboratory1 not yet tries in plant. "48 Process" not satisfactory in plant. DUP030003690 MLS. XIX Aspen Green "Flow Kota" % FINISHED PRODUCE CODE STATUS "48 Process" Base 7M-5497 H-506 KS-5243 Gssein-Dowieide Solution Water Potassium trlpolyphospbabe I^o SsT""HSSPRJb Clay " W-93 ' "Tl Pure" - Z -723 Pigment 0ren-B H-506 Water > ."48 Process" Base 0-733 Bopeo 1407 anfclfoars 0-729 W.D. soya lecithin H-506 Via ter B-224 Butyl cellsolve 6-728 Dow Latex 76-g-W . r ' i. '547-5012 Pigment Oreen-B base 547-5009 Monastral Blue base P-547-0-79187 " "" W.-231 Aquablak-L VM-5470 Potassium polyacrylate solution H-284 Ammonia Total - 100 Gallons Stormer - ICG Pigment Volume - % Solids by volume - % P-391-0-89982 Improved P-548-IJ-8998I 96 68 2' 162 - --m 560 6 12 97 10 357 . 44 m 16 ' Ian ' 7%2 40 40 391-023 Current 547-999 l43 * 168 4 :'76 640 .6 11 46 10 377 18 '4 *** 1 16 1129 ^ r2 40"* 42.9 DUP030003691 --10-- TABLE IV Bellflower Blue "Flew Kobe"; Finished Product Code Status P-39L-6-899$6 39I-OI9 Improved Current "48 Process" base VM-5497 E~506 KB-5243 casein - Bowicide solution Water Potassium tripolyphosphate ' W-1002 W-93 , H-506 "48 Process" base 6-733 Hopeo l407 antifoam 6-729 W.D. soya lecithin H-506 Water H-224 Butyl cellosolve P-548-U-89985 548-829 96 64 ...... . .3.... 130 245 258 122 128 -1 ~ 69 . 585 530 585 65 12 .11 120 T3 10 10 6-728 Dow latex 762-W 547-5065 Red iron oxide base 547-5009 Monastral blue base P"547"6~79l87 Improved Monastral blue base 359 29 28 ........ 369. 32 21 *9 yM-5470 Potassium polyacryiafce solution H-284 16 * 8 Total 100 gallons 1110 iii4 Storaer KU Pigment volume $ Solids by volume $ 72+2 4o 40.0 72*2 39 41.7 DUP030003692 >11-' TAB LE V Color Variation In Improved and Control Batches Measured on DuPont Differential Colorimeter: COLOR CODE Aspen Green *-*****%& P-391-0-89946 391-023 #33506 391-023 #354315 DESCRIPTiON LIGHTNESS COLOR DIF- BruilP" _F__t_oi-FnERoEN3CSr" out out units Lab batch 58.5 Plant trial 60.4 Lab Control 58.9 Plant production 60.1 Atlanta complaint58.8 batch 58.0 59-3 56,5 57.3 54.7 0.7 1.2 2.4 2.9 4,0 Bellflower Blue lv-391^-89986 P-391-P-899B6 #$ P-39I-B-89942 391-019 #376502 Lab batch Plant trial Lab control Plant control 53-5 53*8 54.6 53-2 52.9 52.7 53-8 52.1 0,3 0,5 1,0 1.3 DUP030003693