Document bOB41rzRVdXOYRkLpgLYQrBoD

4c:-. . ' ;m.. fbominatiloa of tbite Lead ! '.Vi... As ft portion of our cooperative work with the Lead Industries Association, a study was made of the ease of mixing, dispersion, and "irindt.ni; of various White pigments normally usod in house paints, in n .mixture of @0$ (2) and 40 (48) (as used in the SIP vehicle). m****-jder-v-. For the first eoag>arison, pastes were prepared with equal volumes of oil per volume of pigment. The pigment mas added to the oil .in':tfaQ plastograph end allowed to mix for 20 minutes. The plasticity [curves thus produced shoved a peak plasticity reeding at the time of final pigment addition, followed by a lowering to a nearly constant >*3ue at the end. The area under the curve should be proportional to the work done in miring the paste, end was determined by counting the number of unit squares. N39109 8 - M. VAX LOO ff4B - font*. plastograph Mixed Pastes With Equal Volumes of Oil per Volume of Pigmont SgEgSi S-W Q. P. Basic Carbonate - 18 dry Gallons Gallons Plastograph Beading Curve Pigment _ on _ at 20 Min, Feck Area 100 175 55 55 80 Dutch Boy Butch ifagie Carbonate nm 65 160 150 Dutch Boy S Basic Carbonate wn 50 90 98 Dutch Boy 111 Basic Carbonate i : R 65 1000 585 Sublimed Basic Sulphate - 9 dry ii * no 550 275 Oslo 412 Leaded Zinc n 19 105 215 127 Anatase Titanium Dioxide - 1405 dry 50 R Too dry to nix 1000 - .Rutile Titanium Dioxide - 2175 dry 100 R R .R 1000 - Magnesium Silicate 20 F dry 100 H 40 125 52 Precipitated basic carbonate white lead IXitch Boy 111 shows its characteristic poorer mixing properties cohered with tho usunl types of carbonate, This is recognised by tho producer* Anatr.se TiOs shoos con siderable resistance to mixing, as does rutile* There arc indications, however, that rutile 2175 dry has bettor nixing qualities than anatase 1405 dry. &e next step ms to conpare the pigments on an equal plasticity basis, in preparation for grinding tests. By varying tho mount of oil the plasticity ms adjusted so that in all cases a reading of 100 units ms obtained on the plastogrcph after 20 minutes. Before addition to the plastograph the pigment and oil were nixed together with a spatula, using S-W 00408*. 13. VAN LOO Pont. the minimum amount of work necessary to obtain a homogeneous paste, these pastes of equal plasticity were passed through the 5-roll 8" Kent alU and the plasticity again determined. The production rate was noted, *< attesting to grind all pastes to the same fineness. The aagnesiun sili cate was ground as fine as possible, while still maintaining a reasonable production rate. As an approach to on estimate of the portion of the binder casing under the influence of the surface forces of the pigments, oil absorption values were determined using the standard A.S.T.H. method, using the 60/40 blend of raw linseed end Z3-Z3 bodied linseed. The gallons of "bound1* oil were determined from these oil absorption values. "Total" oil is the total amount in the mixture. "Excess" oil is the total oil minus bound oil. An assumption may be made that the bound oil clings to the pig ment particles and does not contribute to a lowering of consistency as does the free oil. On this basis the volume of -"free" oil was calculated per volume of pigment plus bound oil. Example: 128.5 gallons total oil per 100 gallons pigment " bound oil " t, free oil ' n JidL - 50.5 gallons free oil per 100 gallons 100.0 + 51.9 pigment plus bound oil. See chart on next page. S-W 004085 Gals, per 100 Gals. P ig . plus Bound O il M. vm LOO Festes of Equal Pre-Grind Plasticity 1C ' EteaL '` ' Sa 5! 15 fen I 1 `2- si on Absorption Free' Oil w i- & do . ka. h I? c \B~m q . p. B.C.W.L. 105 40 Butch Bey Dutch BiCtVaLi 100 SO Butch Boy BTS b,.`.l c..w .l .. " * 10S Butch "Boy in xxr;fi.C.ff.L. * 99 ,/MbUnod B.S.W.L. 100 40 20 23 '-.Oslo 412 .leaded Zinc v;* ^.Amte.s Ti08 101 25 98 5? Rutile T102 100 40 ttagnosiua BiHcatc 110 107 .43 5-1/2 128.3 ' 7.2 51.9 76.4 50.5 .50 4-5/4 158.8 6.9 49.8 89.0 59.4 .39 . 4-3/4 127.7 6.6 47.6 80.1 54.5 .15 4-3/4 268.6 11.9 75.0 195.8 110.7 .57 frrl/4 177.5 9.8 66.5 m.o 66.6 .79 6-1/2 171.8 10.5 65.0 106.8 64.*7 .25 6 300.7 50.8 127.1 175.6 76.2 .20 5-1/2 505.1 27.0 120.5 184.6 83.5 .45 2 131.2 20.9 63.5 67.7 41.4 S-W 004036 V*. M. VAH LOO ' * Cent. |I48 j^Cent^ Two nixed pigment pastes were prepared to compare the calculated plasticity of mixtures of two or more pigments with the actual plasticity, fhe oil requirement of the mix was calculated on the oil required by the irriiridual pigments to produce a 100 unit plasticity mix. Actual plasti cities were found to be slightly lower than the predicted 100. Paste Content ifisti,cija Before After Milling Milling Production Rate Gals. Pig./Rr. Fineness 50 gal, 1403 dry 'BO 18 dry ^ 214 " oil______ 90 39 0.20 460 lb. 412 dry *140 " 1403 : 200 18 200 20 F ; 45 Oil____ 73 53 0.37 Pastes with Equal Volunes of . Oil per Volume of Pigment . A further comparison was made using equal volumes of oil per ivolune of pigment.. The paste was mixed on the pony mixer for 20 minutes, ^'measured on the plastograph, milled, and measured again. In each case flOO gallons of pigment were used with 175 gallons of oil. Three zinc ^ oxide samples are to be added to this list. ' Pigment 18 dry B.C.D.L. Ditch Boy Dutch * - HTS 111 ` 9 dry B.s.ir.L. 412 Deeded Sine 1405 TiOa 2175 T103 20 F Mg Silicate ; Plasticity Before Milling After liilling 55 ' 45 55 182 . 70 72 650 255 32 22 20 22 55 55 25 205 48 52 S-W 004087 Sharp decreases in plasticity on grinding indicate incomplete vetting in the mixer. Magnesium silicate vas thoroughly vetted in the mixor since no change appeared after application of further mechanical energy by grinding. S-W QJP. White' load end National's fi.T.S. lead are obviously easy vetting. Anatase Ti02 is difficult to vet, more so than rutile. Acto 450 added to the above pigments and oil ves very effect ive in increasing vetting in the case of the high consistency titanium oxide pastes, but had a negligible and variable effect then the original paste consistencies vere lov. This may indicate vhere vetting agents may be expected to be effective* Work will continue on this project and vill include studies of surface areas, consistencies at complete vetting, etc., to oomporo the mixing and grinding properties of such pigments. We hope to arrive et a measure to predict mixing and grinding properties of multiple pigment combinations including both active and inactive pigments. As a further step in the Lead Industries Association research, blistering tests vere run on various types of house paints to determine riiether lead carbonate content vas of any benefit in regaining adhesion after blistering had occurred and the blistors eventually had subsided. A uniform vhite pine board in tvo sections vas painted vlth the selected paints as tvo coat systems (48 hours between coats) on the face and edges with the back unpainted and allowed to dry for one veek. The panel sections vere then mounted on the blistering cabinet (unpaintod back down) with the cabinet run at 125o P. end saturated humidity. After 72 hours the panels vere removed to permit the blisters which had formed to sub side if they would. After drying for one reek, the paint films vere ' raked severely vith a rough stoel blade to determine the adhesion. The paint systems used included:. ' - . . - .' lest Ho. . Blistering - Adhesion Tests . *. Materials Amolled Seduction Weed Per Gallon P.7.C, (1st coat 1. C (2nd coat L.I.A. Bouse Point OJ 456 J t 1 pint raw linseed oil 1 pint turpentine Ho reduction 51.5$ 56.4$ !. V#r*'" #148 - Cont. 11. VAN LOO Cont. Blistering - Adhesion Tests Cont. Test Ho. Materials Applied Beduction Used per Gallon P.V.C. (1st coat SJ1P 450 Undercoater 2. C r* ,, (2nd coat L.I.A. Boi^se Paint OJ 486 J No reduction " 57.2$ 56.4$ (1st coat 5. Lead-in-Oil L.I.A. BdUse Paint OJ 436 J 100# Soft Paste V.L. 4 gal. Beplacenent Oil 1-5/4 gel. turpentine 1 pint drier 29.1$ No reduction 56.4$ [2nd coat fist coat y. 5. [2nd coat Ti-Sil Bouse Point OJ 427 J Ti-Sil House Point OJ 4S5 J 1 pint ran linseed oil 25.5$ 1 pint turpentine No reduction 28.9$ 1 pint rat? linseed oil 51.5$ 1 pint turpentine No reduction 56.4$ [1st coat Leed-in-Oil 6. 100# Soft Paste tf.L. 4 gal; Boplaceoent Oil 1-5/4 gal. turpentine 1 pint drier 29.1$ [2nd coat Lead-in-Oil 100# Soft Paste N.L. 5 gal. Replacement Oil 1 pint drier 55.2$ [1st coat 7. Bex 436 - SHP Pune Resisting White 1 pint ran linseed oil 50.7$ 1 pint turpentine (2nd coat No reduction 56.5$ (1st coat 8. du Pont Moisture Bes. R.P. OJ 54 J 1 pint turpentine 59.7$ > [2nd coat No reduction 59.7$ Undercoats at 450 sq. ft./gal. Top coats ct 550 sq. ft;/gal; 004089 <I> -8- M. ?AN WO Coat. Blistering - Adhesion Tests ___________Coat. Test No. Permeability Mg./Hr, Based on 24 Hr. Test Blistering 24 Hours 50 Hours Adhesion 72 Hours 1. 1st coat 2nd n 2. 1st n . 2nd ' 5. 1st 2nd 4. 1st 2nd 5. 1st 2nd 6 1st 2nd n N n w n n 2.S 2.7 2.S 2.7 2.8 ' 2.7 2.1 . 2.5 1.9 2.0 2.9 5.0 Hone n Very slight Bad 9H Def. + Fair ftir Trace Definite Pair + Definite Definite + Bad r nR Poor Fair - None None * None Very good 7. 1st 9 2nd n 8, 1st 9 2nd 9 2.0 Bod 2.0 2.1 .* Nona 1.9 Very bod V.V. bad Very poor None Slight Very good It will 1m noted that tMle the permeabilities of ' the films follow the blistering tendencies to a degree, ell the permeabilities are low and ia the sons which normally is definitely below the "critical" permeabilities* However, there is an apparent relation botween lead carbonate content ant blistering and adhesion, except for the du Pont Moisture Resisting Paint, which contains no lead whatsoever. It is pigmented with TiOa, Z2Z-55 sine oxide rnd York Hhiting in the vacuus bodied 0K0 2-1/2 M linseod oil, at a p.v.c. of 40. It is very effect ive in resisting blistering, but it must bo kept in mind that this is still not an acceptable paint from a brushing standpoint. S-W 004090 -lo ll. VAN 100 ConV Otherwise two coats of lead-in-oil or lecd-in-oil under the X&ad Industries topi coat (46# leaded sine, 14j TiOa, 20J& basic carbon ate white lead, 20$ magnesium silicate) or 450 Undercoater (with 47% basic carbonate) under the Lead Industries Association paint, showed considerable resistance to blistering and retain adhesion. The leadfree Bex 456 and the Ti-Sil formulas (no carbonate, 17-1/2$ basic sul fate white lead) show low resistance to blistering, and low adhesion at the end of the test. Further tests must be mode to take care of certain necessary improvements in technique but even the data collected so far is suffi cient to stimulate some Interesting speculation. J177 - Pigment Studies Following a method suggested by the Hewarl: Technical Service, a series of pigments were evaluated as to dispersion properties for the Lead Industries Association. The Hoover Automatic Muller is used to perform measured amounts .of grinding on pigment in oil mixtures. The degree of dispersion accomplished is measured on the Bagmen Gauge. The method used is as follows: . Weigh out 5 gas. of white lead carbonate or its approximate volume equivalent of other pigments. To this add sufficient oil to give a paste consistency similar to that nceonpliehed with 5 gms. BCRL and 0.55 cc acid refined linseed oil, 15 A.V. Mull this mixture with a 100# weight interrupting nt each 50 revo lutions for a pick-up end mixing of the paste. To make a fineness reading, reduce the above mixture with 1 cc mineral spirits and test in the usual manner bn the Begman gauge. Mixture Beeman Fineness . 100 200 500 400 500 .* KaJOfi cc Oil ev. lv lev, Rev. ! S-f Q.P. Basic Carbonate Sublimed Basic Sulfate Butch Boy Dutch Butch Bay HTS Basic Garb. Butch Boy HI Oslo 412 Leaded 21nc Anatase Titanium Dioxide Futile Titanium Dioxide Magnesium Silicate 5 gms. 5 5 5 5 2.25 1.50 1.50 1.10 0.55 0.65 0.S5 0.55 1.00 0.55 1.00 1.00 0.40 4-5/4 5-1/2 6-1/2 4* 5* 6-1/2* 5-1/2 5-1/2 5-6/4 6 4-1/2 5-1/2 6 -** ** -#* _* -** 7 ( 150 ) (200) 5 (6-172) (7 ) 5-1/4 5-5/4 5-5/4 5-1/2 6 5 5-1/4 5-1/4 S-1/9 004091 -v&saim i ' -n- \ y m - Cent, U. VAK LOO ... Cont. *33ulk of amteriol hotter than this rating. S' :i; *f>ersistent large particles; however, hulk of material is fine, A fen remarks are pertinent on the above. As conceded by the producer national's Precipitated White Lead 111 has a fen large particles yhtch are hud to grind, the remainder being fine particles. Oslo Leaded Zinc reduces to its ultimate fineness very rapidly, as does anatase TiOa. Rutile TiOa (2173 dry) is less easy to disperse, The regular lead carbon V,.A'TiS- ' ' ates ore easy to disperse. Magnesium silicate is still 5-1/2 after 500 revolutions, SWF 471 Lead-Zinc Substitutions in SR? The raw material situation is such that it has become necessary to provide alternate formulas to use mechanical mixtures of lead carbonate mS zinc oxide to displace the 412 dry co-fumed leaded sxnc oxide normally used in SSZP. It is polkted out that this substitution mill affect dura bility adversely. The adverse effect is minimized ty careful selection of the zinc oxide, Bcposure studies at Coffeyville, Florida and Chicago indicate' the following zinc oxides to be preferred for durability. 20S9 dry 22dg 8145 as 1707 Ken Jersey X-5Q5 Azo ZZZ-55 ' . Azo ZZZ-11 Azo ZZZ-55 Hem Jersey XX-50 Of the above group, 2145 dry - Azo ZZZ-11 gives too high n consistency for practical formulation and 2295 dry - Azo ZZZ-55 is on the borderline of high consistency after removing all pater from the ' formula, ' leu Jersey's 3QC-505 and Azo ZZZ-55 appear the most likely sub stitution zinc oxides. 1707 dry, XX-50 should be used only as a last fesort, since its durability is .quite inferior to the other alternates given. All of the above substitutions are made in combination with basic carbonate white lead ' to replace the 412 dry on a Chemical equiva lent basis. S-W 004092