Document JRdGE0BVywkBGDJyvavzEVvK

4 YEARS' RESULTS Or EXTERIOR HOUSE PAINT TEST PROGRAM 0007-SWP-043873 N23304 0007-SWP-000127224 4 Years' Results oi Exterior House Paint Test Program by S. WERTHAN* During tlie past three years we have issued several progress reports'" covering an in vestigation of exterior house paint formulation started by our laboratory during the war. This is an extensive study which involved the preparation of approximately 400 paints and the exposure of over 1200 test panels. The aim of the investigation was to determine optimum pigment and vehicle compositions which would result in exterior white house paint of superior performance. A survey was made of first grade house paints on the market just prior to the war, and pigment, oil, resin and paint manufacturers were contacted to obtain information as to the pigment and vehicle compositions that should be studied. Based on these data, the following representative pigment combinations were selected as basic pigmentations for our tests: 1. 15% TiCri-30% White Lead-3()% Zinc Oxide-25% Inerts (Siliceous) 2. 15% TiO.-47% Leaded (35%) Zinc Oxide-38% Inerts (Siliceous) 3. 15% TiOi-40% Lead Free Zinc Oxide-45% Inerts (Siliceous) The indications also weie that a one-to-three combination of Z-5 kettle bodied lin seed oil and raw*4' linseed oil would provide a basic bodied oil type vehicle for the determination of the effects of other formulation variables. The variables covered in the various series of paints are: Pigment Volume (Range 25 to 50 percent) Volatile Content of Vehicle (Range 20 to 58 per cent) "Chief tjf Hie Paint Section, Development Engineering Division, Technical Department, The New Jersey Zmc Qjmp.mv (of Pa ), Palmerton, Pa. (1) "WIt.it 7yj>e oi Post-War Extenor Ifwife Pamf WjJ) be Official Digest. March 1945; "Post- War Exterior House Paint." Official Digest, January 1440, and "Post-War Exterior House Paint,'' Official Digest, March 1947. (2) Wherever raw linseed oil is mentioned, mi unbodied oil, either raw or refined, is meant. 0007-SWP-043876 0007-SWP-000127226 Type of Titanium Dioxide (Anatase and Rutile) (15 per cent) Type of Zinc Oxide (Nodular, Aciculai, Lead Free, Cofumed, Blended, 35 per cent Leaded, 50 per cent Leaded) Type of Inert (Magnesium Silicate, Mica, Whiting, Gypsum, Barytes) White Lead (B.CAV.L. and B.S.VV.L.) Content (Range 0 to 41 per cent) Leaded Zinc Oxide Content (Range 0 to 78 per cent) Lead Free Zinc Oxide Content (Range 0 to 60 pci cent) Inert Content (Range 7 to 65 per cent) Mica Content (Range 0 to 15 per cent) Many other types of oils and resins were suggested as leplacements for the Z-5 o j ! in the one-to-three combination of Z-5 kettle bodied linseed oil and raw linseed oil vehicle. The following were considered worthy of inclusion in the investigation: 1. Linseed oil kettle bodied to "Q" viscosity 2. Conjugated lmseed oil 3. Conjugated soya oil 4. Maleic treated linseed oil of "Q" body 5. Kettle bodied maleic treated linseed oil 6. Maleic treated blown linseed oil 7. Bodied dehydrated castor oil 8. Pentaerythritol ester 9. Bodied pentaerythritol ester 10. Bodied maleic treated pentaerythritol ester 11. Sorbitol ester of "H" body 12. Bodied sorbitol ester 13. Two different alkyds blended witli linseed oil 14. One of the alkyds cooked with linseed oil 15. A carbic-hnseed oil varnish 16. A carbic-soya oil varnish Since a repetition of the formulations used with the Z-5 vehicle with each of these combinations would have been an almost impossible undertaking for any single labora tory, only a limited series of selected pigmentations were used with them. It is believed that the data obtained, when "tied-in" with that from the Z-5 linseed oil paints, will indicate tile best formulation for each specific vehicle. Paints were also included covering representative pigmentations in the pre-war raw linseed oil type vehicle, in which the binder consists of a ten-to-one ratio of raw linseed and "Q" kettle bodied linseed oils. Series of paints covering representative specification and proprietary paints of the pre-war and war periods were included as comparison standards. Also, painting systems using special primers were covered. 0007-SWP-043878 0007-SWP-000127228 To assure that the results when available would be of practical value, all paints exposed on the fence were formulated to possess satisfactory brushing at normal application consistency. Panel Preparation and Exposure Two types of panels were selected for the test fence exposures--assembled clapboard and single boaid panels. The clapboard panels consist of two new boards and two painted boards. The painted clapboards were obtained by stripping the south side of a large building to provide comparable weathered surfaces for all tests. After taking these precautions it is regrettable that through lack of foresight these boards were stored under very warm, dry conditions. They were then assembled into the test panels, painted and exposed on the fence. Shortly after exposure, paint film failiues de veloped in many cases due to warping and cracking of the boards. The value of these tests is therefore questionable so, in general, we have based our conclusions on the tests on new wood. Botli because the trend is toward two-coat work and to expedite obtaining results, all of the paints were applied to panels as two coats, although a number of the paints were also applied as three coats so comparisons would be available. Preliminary re sults showed the properties of the various experimental paints were such that reduc tion for priming was not necessary. Therefore, the paints were applied as first coats without reduction, but comparative exposure tests were included covering a number of the paints in which they were reduced for the first-coat application. All of the paints have been under observation for stability during shelf storage. Because of the large number of paints it was not possible to prepare and expose all the panels at one time. They were separated into groups and the preparation and exposure of the various series of test panels on the fence extended over approximately a year. All of the paints were exposed on our test fences at Pahnerton, Pa., the clap board panels vertically and the single board panels at 45 facing south. Some of the paints were also tinted and exposed vertically on single board panels. Besides the ex posures at Pahnerton, several of the paints were exposed on clapboard panels at four other localities (Florida, California, Colorado and Illinois), A large percentage of the panels now have been on the fence for at least four years and have reached a stage of weathering where many final conclusions mav he drawn. Most of the three-coat systems are still in excellent condition and are following the same type of weathering as the two-coat systems. It will require at least two more years' exposure before final conclusions can be drawn from them. The indications are that the relative ratings of the formulations by the two- and by the three-coat systems should be in good agreement. 0Q07-SWP-043879 0007-SWP-000127229 Pre-War Linseed Oil Type Painl Bodied Linseed Oil Type Paint Extnor house paints comparable to high grade prewar linseed oil paints can be formulated using a vehicle containing a high percentage ol a heavy bodied linseed oil. (Two coat* on new whit* pm*-- *xpo**d 4 y*ar*--***rUeel, lacing toulh Inatft* at* 4 diam*t*f magnification.) PIGMENT FORMULA 15% TlO^ (Rulll-* 30% While LMd 30% Zinc OxJd* 25% Sihctouj In#rte 0007-SWP-043880 0007-SWP-000127230 Weathering Properties of Pre-War Type vs Bodied Linseed Oil Type Paint The weathering results now provide an answer to the question: Can as durable paint be formulated with the war type bodied oil modified vehicle as with the pre-war raw linseed oil type? Comparable exposures of paints prepared with the two types of vehicle covering a wide range of pigment compositions consistently show durability advantages for the bodied oil type paints. The graphs in Chart 1 cover the weathering of a representative set of these paints. The bodied oil paints had lower original gloss and during the first vein or 15 months developed heavier chalking, but after that period the two paints were equal in these properties. In later life the bodied oil paints devel oped less ciosion and less checking and cracking than the pre-war type. The lower gloss of the bodied oil type paints, in which we used siliceous inerts, might be con sidered a disavantage by some consumers. Still, we have never considered high gloss a criterion for good outside house paints. Chari 1 0 3 6 9 12 IS 18 21 24 27 10 3 3 38 39 42 43 48 D#< Mar. Juni $*p D*< Mar. June $p. D Mar. Jyn# Spt. Doc. Mar Jun* $pt. D*e. nj 0007-SWP-043881 0007-SWP-000127231 Weathering Properties of Pre-War Pigmentations in Bodied Linseed Oil Type Vehicle The exposures have established that, using a combination of raw linseed oil and heavy kettle bodied oil as the non-volatile vehicle, durable paints are obtained with all three of the standard basic pigment combinations: Type 1--15% TiO--30% White Lead-30%Zinc Oxide-25* Inerts (Siliceous) Type 2--15% TiO----47% Leaded (35%) Zinc Oxide--38% Inerts (Siliceous ) Type 3--15% TiO.'--40% Lead Free Zinc Oxide--45% Inerts (Siliceous I Graphs representing the weathering of these thiee paints aie shown in Cluit 2 These cover four yeais' vertical exposure facing south of two-coat applications of the These two panels of bodied linseed oil type paints dem onstrate the desirable weath ering characteristics of such coatings -- good appearance, chalking type of weathering with subsequent erosion, and a favorable surface for re painting. (Two coate an new white pine- or posed 4 jean -- vrUectL, laden* south, liuoris ars 4 diaekoior mcgalflection.) 0007-SWP-043882 0007-SWP-000127232 paints to assembled test panels o new white pine clapboard siding. It is quite evident from these results that all three paints possess desirable weathering characteristics and are, after four years' service, in excellent condition for repainting. The similarity of the weathering characteristics of the three types is striking. All chalked at a reasonable rate and none developed any integrity failures until the film had become thin by erosion. The panels covering three-coat applications are still in excellent condition and should require at least two more years of exposure before they reach a repaint condition. The chalking curves are interesting. It has been our experience, as in the case of these paints, that chalking, that is, quantity of removable chalk, follows a cycle, leaching maxima in late summer and minima in late winter. As shown in the chart, when the film lias been sufficiently thinned bv erosion so that any wood begins to be come visible, we discontinue chalking gradings and report degree of erosion. Chart 2 Wiathcrinj Results of the Three Types el Bodied Oil Paints 0 D*c. 3 Mar. 6 Juris 9 1 2 15 18 21 24 27 30 33 36 3? Sspt. Dsc. Mar. Juns Sspt. Dm. Mar. Juns Sspt. Dm. Mar. 15% TiOj--30% Whit* l*od-30% Zinc Oxid*-25% li*rft <S1k*ou) 15% TiOj--47% ladd (35%) Zinc Oxid*-38% !n*rt ($iticOh) 15% TiO*-40% Zinc Ocid <l#od Fr**M0% Mito--35% in*rf (Siliecoui) 42 Juns 45 Sspt. 48 Dm. Effect of Chang** in Pigmentation of TuiM-prool Paint* A The bodied oil type vehicle permits considerable latitude in pigment formulation. This is indicated by the good dur ability ol these three paints which cover a range of ZnO content from 30% to 50%. This feature enables paint manufacturers to produce special purpose coatings, such as fume-proof (lead free) paints, of superior perform ance. PIGMENT FORMULAS A BC T1O1 XX" 2ine Oxid* 15% 15% 15% 30 40 50 Mica 10 10 10 Magnesium Sihcatt 45 35 25 100% 100% 100% 'Two coats on new whits pins--sspossd 4 ysars -- vsrtical. lacing south tnssris ars 4 diamslsr magm [icaiton t c 10 Effect of Changes in Pigmentations on Weathering Properties Many variations of the three basic formulations were exposed to determine the opti mum ratio of tlie pigment constituents in each type of pigmentation. While the tita nium dioxide content in the pigmentation of these paints was maintained constant at 15 per cent, the white lead content (B.C.W.L. and B.S.W.L. from the leaded zinc ox ides ) and ZnO content were varied over the ranges shown in the following table. The remainder of each pigmentation consists of siliceous inerts: Formula Tvpe 1 Type 2 Type 3 White Lead Content L8 5 to 52 51 S 5 to 35f Nil ZnO Content 15 to 40J 15 to 50* 30 to CO? It is interesting that these wide ranges in pigment composition did not result m marked variations m paint service. While the paints containing pigment combinations typical of those used m first quality pre-war house paints were among the best m per formance, all of the paints provided reasonable service. The results indicate that the formulator has greater latitude in the pigment composition of his first grade house paint when he uses a bodied oil type vehicle. For instance, depending upon his preference, he can use high lead content or eliminate lead and still obtain paints of comparable excellent durability. Also, by judicious selections, he can use high per centages of inerts and still produce first quality paints. This flexibility enables him to formulate special purpose coatings of improved performance. For example he can pro duce fume-proof paints of better drying, appearance, and durability, and by increas ing the ZnO content from the normal 30 per cent range up to the 50 per cent range obtain greater mildew resistance without decreasing durability. For the many who are interested in complete paint formulations, data for the three standard bodied oil type paints are included (refer to Table 1). While our tests indi cate that these paints possess outstanding weathering characteristics, theiesults also indicate thut reasonable modifications of the basic formulations should not signifi cantly change their good performance. TABLE 1 -..................- Formulations ol Throo Standard Bodiod Oil Typo Paints PaintSoi 100 Gill CpUlflOMent Per Cent Lb. Cnl PirviCNT TtUmum Dioxide 75" Le.uled ZnO Lead Kree ZnO CWL SiJicate Mica 61 15 47 ii 25 100 132 4 1 412 85 LU 25 219 92 877 24 3 VtinrLK 39 Z-5 Kettle Bodied Oil Haw Lm^eed Oil Mineral Spirits nml Drier IB 5 4!J 5 74 0 1<KI 0 93 278 190 5(11 1438 11 5 358 29 0 763 100 6 1> V OilzC.il T1O5-C.il \V L , ad ZnOzC.il Jlidinp Power, C.d 33 9% 171 II. 1 32 Hi 2 58 III 2 08 II. 3I5vq ft Ptnnt So _2 100 Gal Per Cent Lb Co/ 59 15 120 37 47 177 78 38 305 12 7 JtKJ 802 24 2 41 165 02 41) 5 34 0 276 189 100 0 .557 1359 114 3.5 7 28 7 75 8 100 0 74 0% 3 68 11, l 20 111 1 22 III 2 45 Hi 2H.5 i<| ft Pmnl So 3 100 Gal Per Cent Lb Cal 54 5 15 105 12 40 275 5 9 35 240 10 69 100 687 45 5 16 5 40 5 14 0 loo o 95 2*4 10 5 574 1261 11 5% .3 79 III l 03 til 10 2 27 22 2 117 16 6 29 6 77 7 mo i 2 75 11. 270 ft 0007-SWP-043885 0007-SWP-000127235 Comparison of Durability of Seli-Primed vs Special Primer System Another observation concerning the bodied oil type paint is that it provides with tv coats of a single paint the good weathering properties of a two-coat special primer s\ tem. The exposures show quite consistently that a two-coat system composed of a pit Prt-Wor Linivtd Oil Typa Paint A 2-coat system consisting of a pre-war linseed oil type paint over a special primer is more durable than two coats of the pre-war paint. (New while pine panels--exposed 4 years--vertical, lacing south Inserts are 4 diameter magmlication 0007-SWP-000127236 war linseed oil tvpc paint over a special primer is more durable than two coats of the pre war paint. In the case of the bodied oil type paint, equally as good durability resulted from two coats of the paint as from a finish coat of the bodied oil paint applied over a special primer. Such results were partly anticipated since these bodied oil type paints possess many of the properties of the special primer--the vehicle is of the controlled penetration type, tiie pigment-binder ratio is high and tile film tends to dry with a idatively loss gloss. Bodied Linseed Oil Type Paint Equally good durability is obtained witb either two coats oi bodied linseed oil type paint or a coat oi special primer iollowed by a linish coat oi bodied Unseed oil type paint New whit* pm# panels--exposed 4 years--vertical, lacing south Inserts art 4 diameter magnification ) Two coats oJ bodied linseed at) type limeh pami One coat oJ special primer Followed by one coot o4 above hmih paim 0007-SWP-043887 0007-SWP-000127237 Thickness oi Paint Films The bodied oil type paint contains appreciably more volatile thinner than the raw lin seed oil type. Therefore, when the two types of paint are applied at the same spreading rate on a non-porous surface, the bodied oil paint will provide a thinner dry paint film. In fact, bv calculation the average thickness of the bodied oil type paint film is approximately 80 per cent of the thickness of the pre-war raw linseed oil type paint film. Our exposure panels were prepared by a painter who lias been preparing them for years and care was taken to apply comparative paints covering the raw linseed and the bodied oil type vehicles at the same spreading rate. Since a thicker film of paint is generally more durable, one might expect the raw linseed oil type paint to provide the longer service. Inasmuch as our tests have shown this not to be the case, we have considered the following possible explanations for the greater durability of the bodied oil type paint. The bodied oil type paint levels much better, leaves less brushmarks. than the raw linseed oil type. The variation in the thickness of the film at the ridges and valleys of the brushmarks is greater in the case of the raw linseed oil type paint. There also is greater penetration of the binder into the pores of the wood m the case of the raw linseed oil type paint. Calculations and measurements indicate the thickness of the paint film at the val leys of the brushmarks may be no greater in the case of the raw linseed oil type paint than in the bodied oil type paint. When applied at a spreading rate of 500 square feet per gallon, two coats of either type of paint on an impervious surface will provide a Bedied Linseed Oil Type Points Level Better Than the Pre-war Type 0007--SWP-043888 0007-SWP-000127238 wet film of 0.0064 inch. The volume content of pigment and non-volatile vehicle in the raw linseed oil type paint is approximately 89 per cent, and 72 per cent in the bodied oil type. Since any change in volume of the binder on drying is insignificant, the average dry film thicknesses of the two paints are 0.0057 inch and 0.0046 inch, respec tively Measurements made on practical brush applications of the two types of paint, using a calibrated microscope and focusing oil the tops and bottoms of the brushmarks, show that the depth of the britshmarks in the raw linseed oil type paint varies from 0 0005 inch to 0.0016 inch. The depths of the brushmarks were so much less in the case of the bodied oil type paint that it was not possible to measure them accurately, still it was established that the most pronounced were less than 0.0005 inch deep. These lesults indicate the minimum thickness of the two films is approximately equal (0 0057 -- 0 0016 -- 0.0041 and 0 0046 -- 0.0005 = 0.0041). As shown in the photo micrographs of the films of the two paints applied on wood, some of the oil of the raw linseed oil type paint is lost through penetration into the wood. Thus, under practical use, if the two paints are applied at the same spreading rates the bodied oil type of paint should provide a slightly greater minimum film thickness than the raw linseed oil type. Just as a chain is no stronger than its weakest link, the durability of a paint film is governed by its minimum thickness. Also, as the composition of the steel in the chain influences its strength, the type of oil in the paint film affects its durability. The rec ognized superior durability of polymerized oil is another factor that may account for the superior performance of the bodied oil type paint. Comparison of Wood Ponotratian by Pro-war and Bodiod Oil Typo Paints A, Cross section risw of a Him ol pro-war llnsosd oil typs point on wood. (1400 dlamstsr SMonUicatton.) Ths Ilia has bssn isducsd In thicknoss. homossnotty and strsngth hy dssp psnstrntton of lbs rshlels. B. Cross sscUos isw ol a Him ol bedisd oil lyps point on wood. (1400 dkamstsi tsasnUlcatton.) Conhollsd ponstraUon prsesnts ions ol ellal oil Into tho wood, ysl snablss ths (ull-bodlsd film to anchor itssli In ihs aulsr wood eUs. 0007-SWP-043889 0007-SWP-000127240 Spreading Rates of Paints The spreading rates of these bodied oil type paints, formulated to brush as easily as the pre-war raw linseed oil type, were compared in the laboratory with those of the latter tvpe by brushing on clapboard test panels. In these tests, under normal temperatuie conditions, the former had spreading rates equal to or slightly more than those of the pie-wai type. We do not have compaiative spreading rates for the paints applied to houses General observations, however, indicate that weather conditions may influence (lie relative spreading rates of these two types of paints. In cold weather, due to the bodied oil becoming more viscous, theie is a tendency for a painter not to spiead the bodied oil paint as far as the iaw linseed oil paint Dining the heat of summer or on verv warm surfaces, due to rapid evaporation of the volatile, there again is a tendency to applv a thicker coat to assure ease in picking up laps. The latter variation may be eliminated to some degicc tlnough the replacement of the mineral spirits in the bodied oil pamt by a thinner of a slowei evaporating rate. Eiiect of Pigment Volume on Weathering Properties The pigment-binder volume ratio for optimum performance in the pre-war linseed oil tvpe of mixed pigment white house paint generally has been considered to lie between 28 and 30 per cent. When the raw linseed oil vehicle in a paint is replaced bv the bodied oil type, the pigment-hinder ratio increases because of the higher volatile content in the bodied oil vehicle. For this reason it was anticipated that the optimum pigment-binder ratio would be appreciably higher than in the case of the raw linseed oil paint This point was covered in this investigation of bodied oil paints by formula tions in which the pigment volume varied over the range of 25 to 50 per cent. While the results weie not sufficiently extensive to establish definite minimum and maximum pigment volume values for optimum performance, the indications are that they will be a little higher than for the pre-war raw linseed oil paint. There is some evidence on the other hand, that by the selection of pigments of high consistency and high oil requirement properties, bodied oil type paint of excellent durability may be formu lated at no higher pigment volume titan pre-war raw linseed oil paint. Although it was not investigated, it is probable that if pigments of low consistency and low oil require ments are selected, durable paints can be formulated at relatively high pigment volumes. 0007-SWP-043891 0007-SWP-000127241 0007--SWP-043892 0007-SWP-000127242 Drying Properties oi Paints A large number of comparative drying tests under various drying conditions, from bright sunny to rainy and freezing weather, establish that the bodied oil paints possess better drying characteristics than either the pre-war ready-mixed paints or lead-in-oil paint. Largely due to their higher pigment volume and volatile content, the bodied oi! paints seem to be more fool-proof and tend to produce better through-dried, nonwrinkled films over a range of practical film thicknesses and under adverse as well as normal drying conditions. Relative Drying el Paint! (PHologropH) a* 9094) The greater the thickness oi film which will dry without wrinkling under cold advene conditions, the better the drying properties of that paint. This feature is used in this illustration lo show the relative drying prop erties oi four paints on a glass plate. The lilms were applied by a wedge-shaped applicator. then dried under adverse conditions. Each film ranges in thickness from approximately 0.0005" at the right edge to 0.01" at the left. The severe wrinkling of the thicker portions of paints C and D indicates that such paints possess poorer drying properties than either of the bodied linseed oil type paints. TiOj Whilo Load Zinc Oxid* (aorta PIGMENT FOBMU1AS A IS*. 30 30 2S 100*. B 15*. 0 50 35 100*. c 15% 30 30 25 100. D 0 100% 0 0 100S Paint A- Bodivd linwtd oil type Paint I--Boditd linsood oil typo Paint C--Pii'War Unsvod oil typo Paint D--Whilo Uod-in oil 0007--SWP--04 3 893 0007-SWP-000127243 Anatase Type TIO* Rutile Type TiOs The definitely improved durability obtained with the rutile pigment, due primarily to a slower erosion rate, is shown here. iTwo root! on n*w whit* pin*--<poud 4 ytars--**rhcal. toeing teuth. liuaM* ar* 4 diamatw magnilieation Th*>* paint* ar* id*alica) in formulation nctpl in typ* of TIO.. Th*y eon*i*t ol th* Joliowin9 pieman' combination in a bodi*<t lin***d oil typ* hid* 15% TI02. 30% whit* l*ad. 30% tine oud* and 25% nlic*ou* in*tt* I 0007--SWP--043894 0007-SWP-000127244 Comparison ol Anatase and Ruffle Types of TiOz The use of anatase titanium dioxide results in better cleansing and maintenance of whiteness, whereas rutile titanium dioxide results in superior durability of a white house paint. The tendency of white house paint containing rutile titanium dioxide to develop a definite yellow discoloration may be a deterrent to its use. Still, the definitely improved durability obtainable with the rutile pigment, due primarily to a slower erosion rate, tends to make its use desirable where uppeaiance is not the mapr factor. Undoubtedly, a pamt system will be dev eloped in which both the durability advantage of the rutile titanium dioxide and the appearance advantage of the anatase titanium dioxide will be realized. As anticipated, the tinted paints that contained anatase titan ium dioxide faded the most rapidly and to the greatest degree, while less fading was obtained with the non-chalking type than with the chalking type of rutile titanium di oxide. Best tint retention resulted with zinc and lead pigment paints (titanium-free). Effect of Other Bodied Oils on Hfeaf/iering Properties The large series of panels in which typical pigment combinations were used with vehicles consisting of raw linseed oil and various bodied oils and resins have weathered 3!a vears and, in general, are in good condition. These results indicate that in the com bination one part Z-5 linseed oil and three parts raw linseed oil, many types of heavybodied oil may replace the kettle bodied Z-5 linseed oil without detrimental effect on the weathering properties of the paint. At this time it appears that the bodied maleic treated linseed oils, heavy-body conjugated linseed oil, heavy-body conjugated soy bean oil, and bodied dehydrated castor oil are all satisfactory substitutes for the kettle bodied Z-5 linseed oil. 0007-SWP-043895 Summary of Results The information developed by this investigation of the bodied oil type of exterior house paint is summarized in the following conclusions: 1. Exterior house paints comparable to high grade pre-war raw linseed oil paints can be formulated using a vehicle containing a high percentage of a heavy-bodied linseed oil. 2. The bodied oil paints formulated for this test program possess satisfactory con sistency, packaging, shelf-storage and application properties and produce smooth films fairK free from brushmarks and of excellent drying characteristics. Then gloss and gloss retention are poorer than those of pre-war raw linseed oil paints 3. White house paints possessing excellent and approximately comparable weathering characteristics can be prepared using any of the following pigment compositions, (1) TiOj-Wliite Lead-Zinc Oxide-Inerts. (2) TiOj-Leaded Zinc Oxide-Inerts. (3) TiOu-Lead Free Zinc Oxide-Inerts In each type of formula excellent performance is obtained with those pigment combinations which were typical of first quality pre-war house paints. Still, die formulator has considerable latitude, since appreciable variations in the ratios of the pigment constituents do not greatly change the good weathering properties of these paints. This enables formulators to produce special purpose coatings of im proved performance with the aid of the bodied oil type vehicle. 4. These bodied oil type paints tend to fail by chalking and erosion. They maintain good appearance until repainting is necessary and then provide favorable repainting surfaces. While they possess lower gloss and develop heavier chalk during the first vear of exposure, the subsequent erosion is slightly slower than for the pre-war raw linseed oil paint. 5. Best original whiteness, retention of whiteness during exposure, and cleansing characteristics are obtained when the titanium in the pigment is the free-chalking type anatase TiOs. Paints containing the non-chalking and chalk-resisting types of rutile titanium dioxide, and especially the rutile titanium-calcium composite pig ment, are not as bright white, tend to retain more dirt, to possess poorer cleansing properties, and to develop yellow discoloration; but paints containing the rutile TiCL possess better durability than anatase TiO . paints. 0007-SWP--043896 0007-SWP-000127246 6. The bodied oil paint can be used without reduction for all coats. When applied as a two-coat system, because of its controlled penetration type vehicle, it provides comparable performance to a two-coat special primer system. 7. The optimum pigment volume of the bodied oil type paint is slightly higher than for the pre-war raw linseed oil paint, due to the higher volatile content in tire vehicle. 8. The tint retention of paints containing tire non-chalking or chalk-resisting types of rutile titanium dtoxide is better than for those based on the chalking type or the anatase grade, but tends to be inferior to the zinc and lead pigment paints (titanium-free). 9. Durable house paints can be formulated using combinations of raw linseed oil and heavy-bodied oils other than kettle Ixxlied linseed, such as dehydrated castor, treated soya and treated linseed oils. Further Work As pointed out earlier in this report, it was not possible to expose all of the test panels at one time. Although the exposures on many are now considered completed, others (especially the three-coat systems) will require another year or two before final durability conclusions can be drawn from them. This study and the results of other investigations have now established that raw linseed oil alone is not the ideal exterior house paint vehicle and that bodied linseed and other bodied oils are desirable con stituents. Availability and economics frequently make the use of still other oils de sirable. Last fall our laboratory initiated a new series of tests in which the use of soy bean oils as the major oil constituents of white exterior house paint is being investigated. Dehydrated castor oil and other oils will be included. As information is developed, it will be passed on to you. 0007--SWP--043897 0007-SWP-000127247