Document Xa0bm42z8XGEVGr5Q9GZ8KbK

E. I. duPont de Nemours & Oo. Fabrics and Finishes Department Chemioal Division Philadelphia Laboratory COMPETITIVE PRODUCTS REPORT Subject: Competitive House Primers and Two Coat Bouse Paint Systems Date Issued December 8, 19VT Period Covered October 1 to November 11, 1947 REfHiBICE COPY NOT TO BE TAKEN ROM UHH N50758 COMPETITIVE HOUSE PRIMERS AMD TWO GOAT HOUSE PAINT SYSTEMS In connection with the recent activation of Release Letter #638 and its supplements recommending the general sale of 347-817 House Primer, a comparison of the DuPont product has been made with five competitive house primers. The comparison covers both the pro perties of the primers themselves and the application in two ooet systems comprising the primers and the topcoats of the same manufac turer. The competitive primers are the following: SR-42078 National Lead Company Dutch Boy Bouse Paint #010 Primer Underooater SR-42049 Sears Roebuck Master Mix House Faint Undercoat #10 Grayish White 3R-42077 Devoe-Raynolds Company House Paint #559 White Undercoat SR-42048 Sherwin-Williams Prepared Paint #450 Underooater 3R-42070 Pittsburgh Plate Glass Sunproof House Paint 1-201 White Primer The competitive Outside White topcoats vhloh have been used over the primers are described in the report on Investigation WT-310 by 0. R. Volk dated June 27, 1947 One topcoat, SR-42058, Pittsburgh #1-54 White was received later and is described in a letter to Mr. John Marshall of October 24, 1947. The Pittsburgh White is a lead free pigmentation and is further distinguished by containing #500 Selected Soya Oil as 25# of the binder. Summary: The house primers fall into two classes according to the pigmentation; zinc-free non-penetrating primers end zinc-containing primers which are similar to topooats in pigmentation. DuPont, Na tional Lead, Sears-Roebuck and Devoe are of the zinc-free type. Pittsburgh Plate Glass and Sherwin-Williams are of the topcoat type. The zinc-free primers are generally lower in hiding than their re spective topcoats, but the zinc-containing primers approach the topcoats in hiding. As compared with the competitive products, the DuPont pri mer may be somewhat deficient in hiding, being lower than Pittsburgh, Sherwin-Williams or National Lead. Increasing the titanium oxide from 1.0 to 1.3 lb. per gallon would place it equal to National Lead and Shervin Williams, and slightly lower than Pittsburgh. All the primers yield two coat systems of satisfactory appearanoe and hiding, although the film thickness is likely to be 4 instead of 5 mils. Durability of the two coat systems will be determined at a controlled spreading rate in Series 9666. DUP030004655 -2- Details: Table Z lists the composition of the primers as calcu lated from the label analyses together with two estimates of their hiding power. Primer Types i The sine-free primers are derived from a pigmentation first suggested by the National Lead Company which was originally 50# titanium barium pigment and 50# basic carbonate white lead. The non-penetrating vehicle was originally advocated by Devoe~RaynoIds Company as part of a two coat house paint system which was claimed to give as good service as the conventional three coat system. DuPont, National'Lead, Sears Roebuck and Devoe-Raynolds are of this type. National Lead has retained almost the original pigmentation, whereas the other paints show a reduction In titanium oxide and white lead content with Increase in extender. The Devoe paint contains a large amount of extender and a high pigment volume, 50#, whereas the other primers are at approximately 40# pigment vol ume. A small amount of varnish is used by National Lead, Sears, and Devoe; the DuPont primer is the only one of this class in which lin seed oil is not fortified with varnish or resin. The use of varnish Is sound in these primers because they do not contain zlno oxide. The Pittsburgh Plate Class primer Is a competing type in whloh the pigmentation is similar to that of conventional house paint topcoat with about the same amount of zinc oxide and the same pigment volume. The Pittsburgh primer oontains no basic carbonate white lead. It probably contains a higher portion of bodied oil or a somewhat more drastically treated oil than the corresponding topooat, but is essentially similar. The Sherwin-Williams primer is intermediate between the lead free type and the type whloh has a topcoat pigmentation* It Is low in zinc oxide and high In the content of basic carbonate white lead. In contrast to all the other primers in this Investiga tion, It contains a large proportion of raw linseed oil and Is not made in accordance with the theory that penetration should be avoid ed. It Is the only primer In which a substantial addition of raw llnBeed oil Is recommended, most of the other primers being so for mulated that the only change which should be made in them is the addition of a small amount of thinner If they drag too much under the brush. Hiding: The hiding of the primers has been estimated in two ways: (1) jt^rom values for the single pigments originally deter mined by R. L. Hallett of the National Lead Company reproduced in Physloal and Chemical Examination of Paints", by H. A. Gardner, 10th Edition, 1946, p. 36. (2) By determination of the contrast ratio over black and white glazed paper at various spreading rates. The determination by means of the contrast ratio has an experimental error about 20 sq. ft. per gallon. The two methods agree fairly well in most cases. DUP030004656 Hiding Is the only property in which 347-817 House Primer is somewhat lacking in comparison with the competitive products. The two sine oxide containing primers, Pittsburgh and Sherwin-Williams have hiding in the range of topcoats and are considerably higher in hiding than the other primers* Of the sine oxide-free primers, the National Lead has higher hiding than the others with the DuPont pro duct second. Technically the hiding level of the DuPont primer is probably satisfactory, since good build and complete hiding can be obtained in a two coat system. However, an increase in the titanium oxide from 1*0 lb. per gallon to 1.2 or 1.3 lb. would place it in a better competitive position and would not be undesirable technically. There is a high margin of profit on this product when it is sold at the same price per gallon as house paint topooats, so that a small Inorease in oost could be tolerated. Application Properties: As a practical test of the primers in two coat ays terns / brush outs were made on unpainted red cedar clapboard. The systems are listed in Table II. The amount of pri mer and topcoat was applied at the discretion of the painter in or der to give a satisfactory film in two coats. The amount of paint applied in each coat was determined by weighing. The spreading rate could be determined from the weight, And the dry film thickness could be calculated from the spreading rate and the known solids content Of the paint by volume. The f ilm thickness calculated In this way does not make any allowance for absorption of some of the oil in the prime coat. This might be considerable in the case of priming coats which contain a large amount of raw oil, such as the pre-war #40 Outside White self primed in system 1 and the ShervlnWilliams primer in system #8. The Devoe primer in system #7 and the Sherwin-Williams primer in system #8 were reduced according to label directions. The Pittsburgh primer in system #9 and the DuPont Primers in systems #2, 3 and 4 were thinned slightly to ease brushing, after trial had shown that the unthinned material was too difficult to brush. The primer consistencies shown in the table are those determined for the reduced material. The viscosity of 347-817 as packaged is too high for easy brushing. It was necessary to reduce the batch of this material with one pint of mineral spirits per gallon in order to obtain good brushing. While other batohes may not require quite so much reduc tion, It is probable that the product could be paokaged at a some what lover consistency and resulting slightly lower solids content and oost. This reduction in cost might be sufficient to compensate for an increase in hiding. The experimental alkyd house primer P-67-P-44562 has been included in the comparison of house primers. This product is prac tical in working properties although it results in a slightly thin ner film than 347*817 House Primer because of lover solids content. DUP030004657 - 4- Two-Coat Films: When the primers are used with current topcoats In two coat systems, film thickness ranging from 4 to 5 mils is obtained. Film thloknesses over five mils can be obtained with high oil, high solids topcoats such as the pre-war #40 White. The only current product whloh Is comparable In solids content and film thickness to the pre-war #40 White Is the Devoe topcoat* The other topcoats are definitely lower in solids and give slightly thinner films. Although there are differences in the gloss and hiding of the primers when applied as one coat, all the two coat systems give a film of satisfactory build and appearance on flat surfaces. At the sharp edge of the clapboard some of the paints containing oil conservation vehicles leave a thin film which presents a point of weakness. The best build on sharp edges Is given by the pre-war #40 with the new #40 White, JO1-864, second. The National Lead White has less build on the sharp edge than would be expected from its high oil content because the brush tends to out through* On the other hand, the Pittsburgh Plate Glass White topcoat oovera fairly well on the sharp edge although it is a paint of low solids oontent and little false body because the paint tends to sag down to the edge. This particular paint was applied at the maximum possible film thickness: if it were applied any heavier sagging might result. Notebook Reference: 74 - 79 #3381 pages 82-87 98 - 101 134 - 135 138 - 141 142 - 143 Gross Referencei Exposure series #9666 WFS?sor PHILADELPHIA LABORATORY i' ` ' * '------- Wo F. SINGLETON ' DUP030004658 TABLE X COMPOaiTIOH AND PROPERTIES OP BOUSE PRIMERS Product 347-817 SR-42078 SR-42049 SB-42077 SR-42048 DuPont National Lead Sears Devoe Shervin-William Titanium oxide Zinc Oxide Basic. Sulfate White Lead B Carbonate " " Magnesium Silicate Barium Sulfate Calcium Sulfate 99 - 3.66 3*56 - Limpid linseed oil Processed Linseed oil fang Oil Besin Varnish Solids .67 2.11 - - Drier & Thinner 2.81 Gallon Weight-Calculated 15783 " " - Determined . . - Pigment Volume -J6 Solids Volume - $S Stormer 39.8 61.1 85 Hldlng-sQ.ft.per galtheoretical Hiding-sq.ft.per gal- determined 197 200 1.43 - 4.75 3.33 Ji-83 - .99 2.56 1578$ 15-20 43.1 62.7 a 236* 215 91 - 3.13 2.06 2.13 3.38 - .19 - 1.91 T57fl 14.0 5876 71.2 72 178 205 .98 - 3.34 2.20 2.28 - 2.23 33 .19 - 1.99 1575* 13.10 53-5 70.0 90 163* 154 1.21 93 .19 4.21 2.83 - 2.53 .83 - - 2.14 14.75 ---S-------- ---- 67.8 89 268 227 Reduction Recommended Has linseed oil Turpentine -- 0 to 1/16 1/4 1/16 to 1/8 ^Calculated for anatase titanium oxide DUP030004659 TABLE II - Two COAT SYSTEM OH NEK RED CEDAR ManuSystem facture Product Reduction 1 DuPont Primer:301-756 prewar(P-301-P-77879) 1/4 raw oil ,Stormer Sq,t./gal (Orginal material) 66 750 Topcoat: ** * " -- 100 a 2 1? Primer:347-8l7(P-301-R-4361)HousePrimer Topcoat:301-756 prewar!P-3C1-P-77S79) 1./8..mineral spirits 6c 100 374 527 364 3 ft Primer:P-67-P-44562 all".yd house primer 1/16-H200 Thinner 65 Topcoat:301-756 prewar(P-301-P-77879) 10U 4 ft Frimer:347-31?(P-301-R-4361)House Priner 1/6 ninar*? Topcoat :301*64<'P-.301-P.-4359;jf40 'White -- K 6* 62 461 402 471 531 Film Thickness -- ma: Mils Brushing Gloss ing 1.88 ii3JL 5.51 1.77 3.82, 5-59 1.67 m 1.9?2.46 Good, thin Low* Fair . flashing Good Flat Fair Fair Flat Fair V. Good Flat Fair G H H H H 5 National Primer:SR-42076 #010 Primer-Undercoater ... Lead icocoa.. --irxlo ---- 6 Scsr*3 pr*5tner:S5l--rflO House Paint Under- -- Roebuck coat Topcoat:Sfi,-ll9l4 #143 White "-- 8? 86 4>C. 92 7 Devoe Primer :SR-42077 #539 Write Unaercoater l/i6 turpertine Topcoat:SR-41916 #547 White ... . _ 89 8 Sherwin Primer: SR-42O48 #450 Unierooatsr Williams Topcoat: SR:41917 17471 Gloss White raw. oil 60 75 9 Pittsburgh Primer!SR-42070 #1-201 White Primer 1/6 mineral 3p-'. i , - _ PlateGlass Topcoat:3R-42058 #1-54 White 490 512 455 508 451 740 439 o35 537 1.92 ZzML 439 1. Zj. 2.46 T&t 2.07 535 1.91 42.3654 2.00 2.06 4355 Good,like V.al. Fair M enamel sheen Egg- Fair 4iicU flashing H Fair,like Flat, Poor M enamel ropy Fair v. low. Fair H SI. flash ing V. Good Low Good R DUP030004660