Document 1QwNVYZwQ6pggj5yV1ZRQ2Dkq

% /OO* f' <* > ( UNITED STATES GYFSU.1 COMPANY RESEARCH CENTER K<OGRESS RE POTT SUMMARY m Pl J. w. B Project Bo. : J-301 Ready Mixed Siaulated Acoustical Spray Finish yellowish discoloration vas found to develop when Ready Mixed Sitr.luted Acoustical pray Finish has aged. A cure has not yet been found, but this tuch has been learned: 1. Bo color developed vhen the product vns stored free one to four days in a dark container, but the yellow color did develop when the six was dried in a lighted area. 2. The clear liquid fraction of the six did not contribute to the color. It contained no iron loos that could change color and no orgrnle solecules that would yellow vhen exposed to light. 3. The discoloration corns fro* the product and not fros the aetal container. h. The discoloration is not dependent on the binder alone, as both casein d polyvinyl acetate baaed system hove discolored. 5. The color is associated with light and is notlcable when the vet Acoustic is dried with light shining on it.' The Acoustic curled in the dark or at lov light levels ooes not discolor. 6 . Reaoval of the asbestos fran the formula and replacing it vlth paper tape sender dust fiber reduces the discoloration. UNITED STATE- GYPSUM COMPANY RESEARCH CENTER PROGRESS REPORT 3-7-66 E. M. J.V.B. Rroject: Ho. J-301 Ready Mixed Simulated Acoustical Spray Finish Synopsis In the last report period, formula SA-223 vas bulletined to be made a* the New Brighton Kill for field tests . A trial batch was nade and a saaple aent to Research. It vas tested and found to be good and ready fo.* field tests. Age Discoloration When the SA-2223A formula Re.idy Mixed Simulated Acoustical Spray finish was made up as a large scale laboratory tec* batch in the Champion mixer on 6/12/6% a five gallon saaple vas saved in a .ive gallon pall with a Harrisite lining. The saaple vas covered air tight and held for six Booths. When the sample pall vas opened, the following vas noted. The lining of the can vas scraped off for about $0} of its circumference at the top lip. This area was mostly covered by a brown gritty material (the grit vas perlite) which vas very easily washed off with warm water and very light rubbing vlth s finger, ine side seam of *hc pail vas in sound condition vltb no dis coloration in the Acoustic or on the u*atlng. The bottom seam vas greatly attacked vlth visible bream and blue-gray gritty lumps that were semi firm, much Tile the ring of material found at the surface of the mix, an inch and a half below the lip of tba pmll. This colored material was also easily washed out of the seam. The coating on the flat bottom and side of tbe pail mas sound with no discoloration. The lid of tbe pall bad e eh'discoloration inside of tbe lip seal. This washed out easily in vara water and light rubbing. Some seim-dry Simulated was on tbe inside top and this had a slight brownish color vher. rubbed with the fingers . On opening the pail two things were noticed about the nix. First, the liquid separation which vas about 1/2" deep vas quite light and clear. Tbe second, vas that there vas a ring of brown and blue-gray discoloration at the surface at the pail wall and extending no more tHmn 3/I** out from the vail and only about 1/2" deep into the mix. This discoloration vas firm when blue-gray in color but very soft when iron oxide brown. J-jOl -2- 3-1-tb Tfae *Sx vu toft, unifom, filled with air bubbles and with r.o tedirrr.t the bottom o* the pail. The pH was 8.1. The viscosity was normal al 22V lirabender using the 5/18" flag paddle. Testa of the Mi. Three small display panels were sprayed out on fresh 3/6" SJEZTRXX. They were dried on the drying rack in the Pilot Plant. When the panels were examined, when dry, it was not'- that over the major part of the panels the color was a yellow tan while on t..e very bottom of the panel, a strip about 1 l/-" wide of white non-colored texture vma found. The white strip corresponded to the heignt of the lip of the drying rack. The panel color should nave been at least as vnite as the 1 1/2" strip. The material sprayed onto the panels was taken from the top center of the five gall~n sample pail. Care was taken not to include any of the darker discoloration at the top edge of the mix. Thus the color did not cooe from the discoloration already viewed in the pail. Check for Color Change A fresh batch of SA-223A was made up and this was tested side by side with the retain sample. The mix had a 5/l6" flag Brabender of 165, a pH of 6.15 and * consistency jf 2125cc /100 gs. of dry mix. A panel each of the aged and fress SA-223A were sprayed and dried In each of the following conditions: 1. 90 T and 90* Relative Hvxaidity in the Light 2. 75 *T and 10* Relative Humidity in the Dark 3. kO*F and 70* Relative Bwidity in the Lark k. The storage rack facing east toward the outside windows 5. and on the work table in the Pilot Plant facing up, well away from the windows. When the panels were dry, they were examined and the following was noted: 1. All panels of tbs fress &A-223 vere white and equal in shade. 2. Again, the panel dried in the Pilot Plant earing the aged texture was yellow tan with a white strip along the bottom equal to the length of the lip of the drying rack tray. 3. The panel of aged texture dried on the table was not as yellow as the rack dried panel. k. The panel with the aged texture dried in the 90*F-92* R.H. room with the lights on was as yellow os the panel dried in the Pilot Plant on the rack facing the windows. There was no white strip at the bottom and there was nc lip on the drying rack in the 90-90 room. 5. The panel with the aged texture dried in the 77*P-10* RH room was only slightly tannlsh and was the lightest of the aged samples. 6. The panel of aged taxtura dried in the cold room was less yellow than the panel from the 90-90 room but darker than the sample from the dry room. 7. All the panels had the saae texture and build. The bond of the texture to the board was conparsblc between pencls dried under slnllar conditions. Analytical Tt.t? A sample of the liquid separation found on the top of the agfd saaple of SA-22JA was drawn of and centrifuged to remove solids suspended in it. The auper latent liquid was then tested for ferrous and/or ferric ions. If Tcrrous ions were present in the wet *ix they could be o Adized to the brown> colored ferric oxide or acetate hydroxide. A-nine hole spot plate was cleaned and to each hole eight drops .. the super latent liquid were added, to holes 3* 6 and nine, one drop o.' on Annoniua hydroxide war added. To holes 2, 5, and eight a drop of 6ff tydroehlorlc acid was aoued. To holes 1, 2 and three one drop of 1.0$ K^FeCClOg was added. To holes U, 3 and six, one drop of 1.0$ XaPeCCN)^ was added. In a separate spot plate a blank was prepares using the K^FeCClOg at one drop in each of three holes. To each bole eight drops of deionized water was added. To one hole a drop of Hydrochloric acid was addra and to another a drop of Aanmiua $rdra)dde was added. The two spot plates containing their liquid contents were set in the sun light on a window sill. There was no initial color change in any spot hole. In the holes vith super latent liquid and acid, a white skin and precipitate were forced. Tr.is was probably the Methocel precipitated free the liquid. After about an hour the blank and super latent liquid spots treated vith HC1 and KjFeCCK) began to turn a light blue green. If ferrous ion were present, even in slight quantities, a dark blue precipitate should fora. If ferrir ion were present, a Prussioo blue precipitate mould fora. Vo blue precipitate foraed, though no iron ions were present. Ihoto Cherical Staining of Ready Mix Simulated The previous work showed that the staining of night be due to some photo chtaicol reaction. To test this possibility four test panels were prepared with alunima foil light abode. The test psuels were 12" x 15". The naterlsl was 3/6" SHEETROCX . The light shades were node of 1 nill aluninus foil, five inches vide and bent so as to stand about 1 1/2" fron the lower surface of the panel and bent in at the top ab^ct an inch so as to cut down on the light entering fron the top and y* to allow ai - to move acroas the shaded surface and dry the panel. The panels were sprayed with the sane stored samples as test. fore snd found to yellow. Coe panel was sprayed, covered and placed on the Pilot Plant drying rack facing the east windows. A second panel was sprayed, covered and placed In the 75f - 10 R.H. room to dry with the incadecent lights left on. A third panel wo* sprayed, covered snd dried in the 90T - 90$ R.H. room with the fluorescent leapo on Report Mo. J-311 PLAINTIFFS EXHIBIT 1547(5) A fourth panel was sprayed, covered and dried In the Jfcotographie dark root (at about 77'F - 50% R.H.) with an Initial two hours exposure to a soft Ultra violet light source, than dried in the dark. Two 2* x . ,/onela f 3/6" SHEETROCX with a simulated Joint of C3 topping were also sprayed with the suspect texture. One vas dried with a small test panel in the 77*F - 10% R.H. room with the lights on. The other panel wus dried alor.j v:th one of the small test panels in the 9C*F - 90% R.H. room. These two large pant-16 were to check f..r any color variation between the board paper and the ,:,oir.t compound or white banding. A sample of the suspect texture was centrifuged to separate a nearly clear whitish liquid from the aggregate and fillers. Two films were cast on glass with the liquid. One was dried in bright sunlight by a window with one half of the film shaded, with aluminum, from the sun and the other dila was dried in the Photographic dark room with .he film exposed to an Ultra violet light. Two small panels were prepared using a sample of SA-223A prepared on 8-7-65. One was exposed to bright sunlight with half of the panel shaded with aluminum foil and the other panel was exposed during drying to 2 hour of Ultra violet lignt wnile half of that panel was also shaded from the radiation source. Test Results Of the four shaded test panels dried under various conditions, the first panel from the 77*7 - 10% R.H. room showed very little difference between the exposed ores and the shaded section. The drying conditions were fast and the light was free 150 watt incandescent loops. The panel dried in the 90*7 - 90% R.H. room under fluorescent lamps showed a vcre marked contrast between the exposed and shaded areas. The exposed area was a yellowish ton while the shaded area vas a white color with only a trace of yellow in it. The pant-1 dried in the photographic dark room after a two hour exposure to an Ultra violet light source vas equivalent to the 90*7 - 90% R.H. room panel, the shade of the exposed area vas the some but the color seemed a lettle less yellowish. Of the two test panels with CS Topping Joint compound on them, the one dried In the 77*7 - 10% R.H. room with the incandescent lamps on did not have a trace of white banding over the joint compound or any other color variation over the total surface. However, the panel dr. M in the 90*7 - 90% R.H. room exposed to the fluorescent lamps did have a distinctly welter band over the Joint compound while the field of the board turned a quite yellowish tan. The color of the white banded Joint vas a little more ervtay colored than the shaded section of the small panel sprayed with the same compound and dried a long side the larger panel in the 90*7 * 9% R.H. room. Of the two glass plates covered with the nearly clear super latent liquid of the aged Ready Mixed Simulated Acoustic, neither showed change of color after exposure to sun light or Ultra violet lignt. iiiiiian<ipaiugiDliPI Report Mo. J-301 -5- 3 7 oo Of the tvc panels applied to 3/8" oJCSTROCX using an aging sample stored in a half pint can raade 6-7-65, the panel dried in blrght sun light with one half the panel shaded at 77*F - 50$ R.H. shoved very little difference in color between the exposed and shade' areas. A slight trace of yellovlng was noted in the exposed area but that wouo.d be considered to be oo problem in the field. The panel dried in the photographic dark roots shaved a color difference between the exposed and shaded areas the sane as the large scale aging sample. Check ftioto Sensitivity of Acoustics The coler development of the SA-223A made on 8-12-65 was not noticed until the material was sprayed out six months later. Freshly made Acoustic showed no color development when exposed to light. Work was done to find out when the ehramophore developed. Thrv e Ready Mixed Simulated Acoustics were mimed. The first was the standard SA-223A formula which has shown color development on aging. The second was SA-223 E which contained 3.0$ Anaonium Phetaborate in place of the l.G$ found in SA-223A. The increase in Brntaborate was to see if it could suppress any rusting of the raw iron in the 7KF5 asbestos which might be the source of the color, `xhe third formula, 6A-223F contained no asbestos but instead contained 5*0$ wood fiber from the paper tape sanding operation at the typsum Kill. This formula .Mso contained 3.0$ Anonlum Jhntaborate as a preservative for the wood fiber. The wood fiber contained no free iron to possibly rust and cause color. Tests * Each mix vms made up and stored in small glass bottles vrmped in aluminum foil. The glass containers removed the possibility of contamination of the Acoustic v*y a met* container. The aluminas foil was used to make the glass bottles lignt tight, thus producing all of the conditions of Acoustic stored in a metal can with out the possibility of contamination. The samples were then stored for a few days, then opened and the contents spread on to two small 3/6" 5HECTT.0CX panels. The bottom half of each panel was mar.ked with aluminum foil shade which darkened the surface of the panel yet allowed enough air across the surface to dry the Finish. One panel was then dried on the Pilot 1'iont drying rack and the other dried in the 90*F - 90$ R.H. room with the flcurwscwnt lights on. Test Results SA-223A showed no discoloration of the texture, either in the Pilot Plant or in the 90*F - 90$ R.H. room, on the day it was made up. A tan color developed over the exposed area of the 90*F - 90$ R.H. room panel after one days storage, however. After four days storage the tan color developed over the exposed surfaces of the Pilot Plant and 90*F - 90$ R.H. roam panels. SA-223 2 showed no color development until after the fourth day of storage when both the Pilot Plant and 90"F - 93$ R.H. roam panels showed a trace of tan over the exposet surfaces. After eleven days, the color development was only trace and not nearly as bad as tbe four day storage of 3A-223A material. Report Ho. J-301 -6- 3-7-66 SA-223 T vu unusual. No color developed over the exposed areas of any samples dried in the 90*F - 90% R.H. room, even after sixteen days. However, after four days storage, the Pilot Plant panels developed a trace yellowish ton color over the exposed or ;. This did not increase in intensity with age but remained the see*. This color was barely cesccrnible. Chech of Other SInulated Acoustics To check the possibility of photo discoloration of other older Acoustics three dry powder formulas were tested. The compounds were mixed then port of each was stored in foil covered glass bottles four two days. ach Acoustic was grread c& two snail test 3/6"* SHE1ZR0CK panels when first nixed. Half of each panel was masked off with aluminum foil in the usual manner, then one panel was dried oc the Pilot Plant rack and one in the 90* - 90 R.H. room. After the compounds were aged two day* la the bottles they were likewise tested on small panels. Teat Results Formula SA-65A, the old Regular Simulated Acoustic discolored over the exposed area on the first day in both conditions. Formula SA-l6l A did not discolor under either condition, either the first day or two days later. Formula SA-1&01, the L.C. formula to replace the SA-65A shoved a slight discoloration over the exposed areas after two days storage. Thus SA-65A would discolor when sprayed as a fresh mix and exposed to light. &A-1BQ2 would possibly discolor if exposed to light if it were kept over a week end, wet is the nixer. SA-l6lA would not discolor if exposed to light if held as a vet nix la the nixer tank over a weekend.