Document ppypY6mNqxY86qRv2KOpw19eD

a l l ie d r e s e ar c h b u l l e t nr V NUMBER RC IS SUBJECT ZINC SULPHIDE HOUSE PAINT EXPOSURE STUDIES E* Carlson H. Jagd ALLIED RESEARCH LABORATORIES Chicago, -Illinois December 1, 193c. N12523 0007-SWP-000006832 ZINC SULPHIDE HOUSE PAINT EXPOSURE STUDIES Statement; Jiany attempts have "been made "by white pigment producers end paint raanu- fecicxers to produce Lithopone paints of equally satisfactory performance compared ,'e head, and Zinc Paints, and to Lead, Zinc and Titanium Paints. Sons of the 'Attempts have been definitely successful. Our exposure tests made over a period of years confirm the above concluea. As the inherent weakness of Lithopone as an exterior usage pigment due to :s high Blanc Fixe content appears to have been well established, further attempts ' the direction of establishing of Lithopone as a suitable pigment in exterior ity paint8 have been abandoned by this department. Whether increasing the Zinc Sulphide content of Lithopone from 28$ to and reducing the blanc fixe content from 72$ to 45$ as in the Double strength depones of which Crypt one is typical, is sufficient to prodice quality paints 'satisfactory durability is still open tq question. Also, the question of' the maximum durability obtainable with Zinc Sulphide th the complete replacement of Blanc Fixe with other inert pigment combinations, reially those containing Mica, remains to be determined. Further, the inherent characteristics which can be introduced into pure Inc Sulphide by variations in the manufacturing process which work towards in- ised durability have not been fully established. The following report discusses briefly the results of exposure studies all of these three lines of endeavor and presents an outline of further exposure tudies based on the encouraging results already obtained. The exposure studies on Calcium-Zinc Sulphide pigments will be dealt with `another report as they represent a separate line of endeavor. ' Zinc Sulphide Pigments-ffeet of Partial Re-placement of Blanc Fixe On Durability The demand for increased hiding power resulted in the production of the er strength Zinc Sulphide pigments of the type represented by Cryptone produced Hew Jersey Zinc Co., and 12C~C by S-W Co., in which the Zinc Sulphide content raised from 28$ to approximately 55$ and the Blanc Fixe content reduced from to about 45$. Series; _ - Based on exposure results reported by Hew Jersey Zinc Co. end earlier osures of our own, it was felt that this pigment - Cryptone - had sufficient e-roved durability over Lithopone to permit of its introduction into S-W. s Family it.. 0007-SWP-000006833 .flint Silt in the spring of 1933* The pigment combination per 100 Gals, being; \bfc *\; . 300 Lbs. Crypt one or 3g$ 200 " Leaded Zinc 35/^5 11 25$ 300 Inert Pigments 37$ (lab. and Silica) This formula and variations of this formula were exposed covering - a. Beplacemont of the Cryptone content with Leaded Zinc, 412 Dry. b. Bcplacement of the Cryptone with Titonox B. c. Replacement.of the Cryptone with an equivalent amount of Zinc Sulphide and the Blanc Fixe replaced with Asbestine and Silica. d. Beplacement of the Cryptone with 5 experimental lots of S.tf. *s production of 120S-C. , These formulations were exposed as 3 coat work on both ffiiite raid Tellow iPine, S.If.P. 'foite, Hex 471 (Titonox B formula) applied as a guide coat on a pox- ion of each panel to detect wood differences. The exposures have gone through four summers, equal to about 5 years on house job or about the normal life of a white paint job. Due to the composition and the considerably greater opacity of the S.f.P. ""guide coat, it might be espected that it would show a marked superiority in dm-- Jj^bility. This was not the case. On Yellow Pine, the behavior of the entire series fjsas comparable with the S.W.P. Ihite, and represented a fair degree of durability, t* except the replacement of Cryptone, with Leaded Zinc which showed considerable "cracking. Otherwise, no marked superiorities or deficiencies were observed. 11 Si On tfhite Pine marked differences were shown. As a group, tho 7 Zinc lphide exposures showed marked durability over the 7 3.7.P. jJhite guide paintings of the latter .showing pronounced flaking and scaling, this feature being sub- " j|stantially absent in the Zinc Sulphide paints. Interpreted on the basis of the performance of the glide coat as climlating wood differences, one panel with another, the Bow jersey Cryptone was slightly superior to the 5 Coffeyville experimental Double Strength pigments. " ise showed no substantial differences one with another. The Cryptone Family Paint exposure Bhowed a moderate number of barely fislble cracks limited t one portion of the panel. The S-B.P. tfhite guide showed Considerable crocking with incipient scaling. The Cryptone replaced by Leaded Zinc showed extensive fine checking and fracking. & ,The Cryptone replaced by Titanox B showed extensive checking and cracking ^similar to the S.tf.P. Thite guide paint. The cracks being of the long type. .'During the earlier part of the exposure cycle, this paint presented the whitest \^4nd best appearance. After four summers, it shows no superiority as to whiteness, '.4iding power and appearance over the Zinc Sulphide paints. 1 0007-SWP-000006834  *4;' Cryptone replaced by a mechanical admixture of Zinc Sulphide, Asbestine -s silica showed no improvement to date. ^ 13hil the hiding power of this series by reason of the 37$ of added jiiiert pigments was less than that required of a first grade paint, none of the films have become excessively thin and transparent. x. ,jr i o^ She wearing value of this Family Paint vlhite based on Hew Jersey Crypt one 1 rtnol 1w A frtr* rx aar*n*nA AU" MtilitV Unint. A T* .Wrst 19 3** Series; $ A similar pigmentation to the 1933 series was selected as one of the formulas to determine the durability of various semi-drying oils. The pigment Combination in 100 gallons being; i:'- 300 lbs.Cryptone 300 * Leaded Zinc 35/^5 150 n Asbestine 1K.- 150 Silica i. ? This formula made with Linseed Oil was applied as the guide paint ^,[,3 coats) on 12. Thite Pine and 12 fellow Pine panels. After three summers' ex- t' posure, no checking or cracking of the film has taken place. Appearance good. % j- The same formula with various replacements of Linseed Oil with Soybean, Sunflower, and 7alnut Oils on 9 "hite Pine and 9 Yellow Pine panels exposed at the *' seme time gave the same results as above.: ^ 4_ The above panels show a similar degree of whiteness compared with the ^ "J or,her panels containing Titanox 3 and Titanium Oxide. -T / Again, we are confronted with a series of paints containing 50$ of inert ^pigments which are exhibiting the type of durability performance commonly associated <swith a first quality paint. *\ / -'Second 1934 Series; pother series of exposures were put out later in 193** which have now had 1: full two years8 exposure which throw further light on the durability factors 01 Crypt one compared with Lithopone. The formulation selected was that of Zincite Thite of Montgomery Tard, a house paint having a wide sales in the medium price grange. The pigment comoosition for 100 gallons being; * 515 Lbs. Lithopone < or 55$ 330 " Leaded Zinc 35/65 B **5$ 95 M Asbestine " 10$ On V3iite Pine this paint has shown bad checking (of the small pattern 0007-SWP-000006835 Replacement of Lithopone with Cryptone shone marked improvement, very ilight checking confined to a very small part of the. panel.- A l/3 replacement of the lithopone with Crypt one shooed, very moderate decking: over entire panelE appreciably tetter than .'that Of the straight lithopone. %- This series also contained several exposures "based on & somewhat different pigment combination as follows! " Bp || . 295 Lbs. Gryptone 295 ' Leaded Zinc 35/fi5 y h:i 14 g 8 l4g 8 Asbestine Silica This paint after two years! exposure on .Thite Pine used as a guide paint on several showed on one panel considerable checking and cracking on the other Ipanels slight checking only. Replacement of the Asbestine and Silica with a Talc possessing a definite ate8 particle structure, showed no checking. Replacement with Mica showed no checking and the appearance of some ^residual' gloss, possibly because of the mica effect. V s' An additional exposure series is now under way which is designed to ex- . r.~ 'j tend our knowledge of the effect of varying percentages of Mica on.durability. xized Results; The replacement of normal Lithopone in exterior paints with a high Zinc Iphide content pigment similar to Gryptone, in which the Blanc Pixe content has een reduced from 72# to 45# greatly increases durability. The durability has been increased sufficiently to justify the usage of ich a pigment in conjunction with Leaded Zinc in general utility or second grade lints where good hiding power and fair durability are required. The high total inert pigment content of 4o#*50# permitted by this type 9f. formulation and with the maintenance of excellent hiding power, does not appear to affect the durability adveysely-a factor of importance in obtaining the low |costs required with the competitive type paints. Zinc gulnhide Pigment s-Effeet of Complete Blanc gixe Replacement on Lurability `a'f'ip' Exposure studies made with the complete replacement of Blanc Eire with , , pother inert pigments, such as Asbestine, Talc, Amorphous Silica, Mica, etc. may be .ij considered under two phases. One in which the inert pigments are brought into Ucontact with the pure Zinc Sulphide as a wet slurry end second, when introduced >, <ky in the paint mixer with the pure Zinc Sulphide, most of the exposures being of v' 4!latter type. 0007-SWP-000006836 jQgq Series; . The initial exposure tests were 'begun in 1929 and were "based on admix tures of Zinc Sulphide, Leaded Zinc 35/65 and Asbestine. The tfiiite panels checked considerably within three years, the Cream tints showed much greater durability. One of which is still on exposure, showing excellent tint retention, good adhesion end good general appearance, but with extensive fine pattern checking. This com position tas represented by: 60^ Leaded Zinc 20$ Zinc Sulphide 20$ Aflbestin Too IQ'^O - Series; The subsequent exposure series put out yearly up to 1934 were based on the inclusion of varying percentages of 'fiiite Lead, both Carbonate and Sulphate, in addition to the percentage derived from the Leaded Zinc. This under the belief that a substantial percentage of "fiiite Lead was necessary for durability. These exposure tests showed considerable decking with the Whites in two years, and the tints in three years, when considerable percentages of Shite Lead (B.C.) were present. Increases in durability were observed corresponding with decreases in Thite Lead content sad moderate increases in the Silica - Asbestine content. It was concluded from these tests that fihite Lead in amounts beyond that Introduced through the Leaded Zinc lowered the durability of Zinc Sulphide formu lations. Pirst 1934 Series; In 1934 two aeries of exposures were put out on "hite Pine, one based on the Zincite formulation (see caption A, page 3, for composition)'in which the 55/6 of.Lithopone was replaced by mechanical admixtures of Zinc Sulphide and inert pigments. The outstanding member of this series as to performance is composed of 45$ Leaded Zinc 35/65 55$ Crypt one MS-130 (Zinc Sulphide (Asbestine (Mica 10$ Asbestine V After three summers' exposure the film is in perfect condition with no evidence of checking, while the guide paint containing 55^ Lithopone is badly* checked with flaking between coats. The use of either Asbestine or Talc alone in place of the above combination of Mica and Asbestine introduced os a mechanical mixture in the paint mill, showed evidences of failure through very moderate checking, some preference being given to the Talc. 0007-SWP-000006837 :^ona 19&'Series:; . 1. lfee second 1934 eerie, exposed in September on White Pin, was repre sented by the following pigment combinations % 30$ Zinc'SuljMde (Hew Jersey Zinc Co.) 46$ Leaded Zinc ' 19$ Asbestine 5i^ica She other variations being substitutions of different Sine Sulphides, A After two years' exposure there is no evidence of checking or other Vgne of failure in this series. Appearance uniformly good. f-/ ' * t?* Cooperative Exposure Tests: 4. 'c* In the spring of 1935 a cooperative exposure test was arranged between -.Lrebs, The Titanium Pigments Company and this department to study the influence of (climate and personal equation factors on six typical formulations including a lithopone and a Zinc So-lphide formulation. The paints were applied at the same ,'Vime with identical reductions on Cedar and Douglas Kir, Exposed by the Titanium figments Company, at Seville, Long Island, Krebs, at Wilmington, Delaware, and by ^.bla department near Detroit. White Lead in Oil was used as the comparison of ^guide paint on each panel. This exposure series had as its basic aim a comparison of the durability [of the following type formulas over new wood and ultimately their behavior on ^repainting. This latter feature being regarded as of particular importance. 1. 60$ White Lead (B.L.C.) 30$ Zinc Oxide 10$ Asbestine (Old conventional type ) (White Lead and Zinc Oxide) 2. 35$ Titanox B 45$ Leaded Zinc 35/65 20$ White Lead (Similar to former SWP) 3. 37$ White Lead 38$ Leaded Zinc 35/65 12-1/2$ .Titanium Oxide 12-l/2$ Asbestine (Similar to present Lowe Bros.) 4: 40$ White Lead 40$ Titanox B 20$ Asbestine (National Lead Co's recommends.-) (tion for a zinc-free paint ) 5* 55$ Lithopone 35$ Leaded Zinc 35/^5 20$ Asbestine 6. 30$ Zinc Sulphide 35$ Leaded Zinc 35$ Talc (Krebs1 recommendation for) (Lithopone paint ) (Selected on basis of previous) (good performance ) 0007-SWP-000006838 -7- Sheee.paints were put out in June, 1935 and have had one winter end two exposure.. A recent check-up at all three locations shows the following? 1. fee '`fhite lead guide coat shows the typical checking or "flaeurlug" Of Shite lead. Moderate checking and cracking of the 0 lead JO Zinc 10 Inert pigment combination. Slight to moderate checking of the 55"^ lithopone formulation.' 4. Moderate chalking, no checking and general good ,'PiilX appearance of other 4 paints. iy - firasuaer Usage; t'f- The initial Zinc Sulphide exposure tests begun in the spring of 1929 keying shown definite promise, it was decided to offer for sale through one of the * "affiliated companies, a paint based on pure Zinc Sulphide. This paint was intro duced to the trade in semi-paste form in 1931 and sold only to the painter trad *end not to the general public. r' /? The following yearly increases in production indicate a high percentage repeat sales. One gallon of the semi-paste when reduced equals two gallons of :.-rcady mixed paint. Tear Gals. Semi-Paste Converted to Heady to Use Basis 1932 1333 1934 1935 1936 7,456 11,739 15,756 27,^40 36,405 14,912 23,472 31,512 ` 55.220 72, BIO IpC The pigment formula is approximately: I* 30^ Zinc Sulphide - 45$ leaded Zinc >'.% jfjf': 20$ Asbestine 5$ Mica (Introduced in 1934) J Up1: Ho complaints -have been received as to lack of durability or poor appear|||oce on continued exposure. Various inspections made by this department indicate `^6 performance comparable with that of a first quality paint. ..jjuamarized Results: The complete elimination of Blanc Fixe through replacement with the i.silicate type of inert pigments-Asbestine, Talc and ' ir;rceuus"S15iortes fuffher t increases the durability of Zinc Sulphide paints. 0007-SWP-000006839 1 m -g- Greatest Increase in durability obtained with an Asbestine and !4iea ad- The durability characteristics attained in this manner compare favorably tith and perhaps exceed those cf the widely used conventional formula of fO head, JO Zinc and 10 Inert of a few years age for first quality house paints. Exposure results not yet sufficiently complete to make definite eomV y ^orisons with the best Lead, Zinc and Titanium Oxide formulations. Durability Characteristics of Different Zinc Sulphides a* - It has been recognised that the durability characteristics of various pigments vary accordingj to differences in the physical structure of the "pigment particle. It is therefore conceivable that the inherent durability, of Sine Sulphide can be increased by exposure studies based on differences as to rsieal structure. An initial series of six experimental Zinc Sulphides were exposed in .Florida in the spring of 1934 based on the following pigment formulas 330 Lbs. 420 115 Sine Sulphide Leaded Zinc 35/^5 3asic Lead Sulphate Asbestine Silica At the end of two years1 Florida exposure varying degrees of checking I.j; had taken place, clearly indicating that differences in the Zinc Sulphides used, \ produced appreciable differences in durability. The Zinc Sulphides having a phyeical structure resulting in considerably lower oil absorptions showed increased :|f durabilities. A further exposure program is being outlined which will expose this 'field more thoroughly. h . Coneluding Stat ement: ;. The exposure results obtained by. this department and confirmed by the |fladings of other technical organisations, present the broad picture that the high strength Zinc Sulphide pigments are now usable in first quality exterior house ^paints. That it will be a matter of personal preference, rather than of funda mental superiority, as to whether exterior paints, will in the near future be Formulated with Titanium or Zinc Sulphide; Vi< 0007-SWP-000006840