Document aJLdn6zKDkVVJKVOJx1y0gZJa

[3 DIRECTOR OR RESEARCH ( j I I! FOR WAT I ON RETRICVAl. | | central Rile fx) SECT I ON FILC AND UI BTR I BUT ION bZLOW C (REPORT j U.f! 'ft0 `STATES GTPSUM RESEARCH CENTER Wallboard Finishes__laboratory PftC'fr.TSS R?;rGRT----------------- - THi~S~RPMt~Ma~h5T~BE REPRODUCED ADDITIONAL copies op distribution outside THE COMPANY REQUIRES APPROVAL OF DIRECTOR OF RESEARCH. ____________________________________ FILE NO. RETORT NO. CATE TYPED REFERENCES 19192 3-6-72 H.3. 304 Pgs, 44- PLAINTIFF'S EXHIBIT USG-508 TITLE: Asbestos Free Dry Powder -Joint Compounds SIJMUA!:Y: During this report period work was continued on the project to eliminate asbestos from dry powder joint compounds. The object at the present time is to obtain acceptable application properties. Two different appicaches were tried. One was to replace the asbestos with one or more raw materials. The other method was to use a high viscosity binder, trying the binder as the sole means of increasing water demand and gelling the binder slightly with ammonium pentaborate. The idea behind inducing the gel character was to provide slip for application with the gel. Tests showed that of the asbestos replacement tried Attagel 40, Keizer., Kelcc SCC-LY, Kelco 3CS-HV and CMC-2 showed the most promise. While Attagel 40 provides fair application properties, it does have adverse affects on shrinkage and cracking. It is also very thinotropic and ecus os the compound to break down too much on trowel applications. . Kelz.an, lvclco CJC3-LY cud Kelco 3C3-KV all provide good-slip for applicat ion, however they have a lev; water requirement and therefrre dry out rapidly when being applied. Compounds with CMC-2 had a ve"" high water ic:. but lacked the good slip for application. An interesting feature of the compounds with CMC-2 was that even with the high water usage there was no loss in bond or change in shrinkage. Further tests-will be conducted with these raw materials both separately and in combination as well as testing new materials. Tests of the high viscosity binders showed that C-P-952-3-, a cold water soluble corn starch, was the only binder tested had some premise when asbestos was eliminated. In the compounds tested it gave some slip for application. Although even better application properties were obtained when it was gelled with ammonium pentaborate the compound had (ir.ro (ion.m RRITTEN T. L. Williams Cl'c if1.J 31...Baumgartner j*_ ,, i.1 * Jl.._ SummericId 1 _ J, J4.-Eobypts. *_____ _ 14 _*_ ..Nies_i________ . m . Eoy_ f__________ rj t. w'A -- V/V/A. APPI;0VL|. BY // 1. D i-L r !' 1 I CN ____________ _____ . n_________ ____________ Q __*_ Summary Only ____________ n_____________ F. Maynard hi Vi pr-cvi. 'A c c File 3-2201 Report 19192 Date 3-6-72 Page 2 Summary Cont'd. higher shrinkage and a loss in bond. VJhen some of the GP-952-3 was replaced by Gelvatol 20-60 BP polyvinyl alcholol an even greater improvement in application was found. More tests will be conducted with this starch and more binders will be tested. 6P00 6