Document Ev6XEazDOrLOLyaNDVq8ML8vV

Dow Chemical Emulsion Paints Dr, Paul Robinson, Lab, Mr. S, J* Welch, Lab Mr, W, 0 Johnson, Lab Philadelphia Laboratory November 3, 1949 fiETURB TO MARSHALL LflBflfjATOHy ` -INDEXED" l.B^uTOW. MPOBI MO. H-270; ' KfMCI Cf bow um baisb PAiarsWit f o r mmmm Mr, Peterson and Mr, Martin of the Dow Chemical Company visited this laboratory on November 1st to discuss the use of Dow*s Latex 512-0 and 529-K (butadiene-styrene emulsions) in water paints. The Dow 512-0 differs from 512-K, previously used, in that it has better freeae-thaw stability. The 529-K, & high styrene content polymer, is not a film former but can be used to harden.512-0, This replaces their previously recommended use of 500 Latex (100$ styrene) for this purpose. The cost of these emulsions is 2j5 and per lb, of solids for 512-0 and 529-h respectively, Mr, Peterson presented two formulas for paints based on these vehicles, copies of which are attached. In the course of discussion, the function of the various ingredients was discussed. The tributyl phosphate is used as an anti-foam agent.and not as a plasticiser. Although it undoubtedly functions as a plas ticizer, it is not necessary for this purpose. The trisodium pyro phosphate acts as a pigment dispersant and as a sequestering agent to protect the emulsion from the effects of metal ions,* They recommend the use of casein rather than Methoeel as a protective colloid since it produces better brushing and flow properties. We have obtained similar results with a Methocel/Nopaicol 6-LW mixture* Pine oil is also added to improve brushing properties. The pigmentation was not extensively discussed except for some comment on the use of lithopone 8 which they included only to demonstrate its compatibility with this system* No unusual proper ties are obtained through its dse. They also suggested the possible substitution of a coarse particle size clay for mica. The1 recommended clay is Edgar Bros, ASP-400 (BS-20013)* The paint dries in a short time and exhibits good hold-out odor, and brushing characteristics Due to the high iodine value (120/ of the emulsion, the film will harden on aging. N35401 -% - They hate not encountered any peeling difficulties, but admit that it is a possibility. Hardening of the film by increasing the 529-K content would be a means of co ntrolling this tendency* Their claim for the cleanability of this film is essen tially that presented by the Glidden Company for its Spred Satin which is presumably made from this resin. Their favorable moisture impermeability comparisons, and presumably those of Glidden Spred Satin, were drawn against other emulsion flats and not to oil solution paints. {A comparison, of Glidden*s apor Barrier Systems with other types of systems will be found in Memo Report M-267.) On exterior exposure over masonry, they have had only fair results, the greatest failure being through errosion and chalking, although they do not get the excessive chalk washing experienced with Bondex. Ho comparisons were made with oil or other emulsion paints. PHIIADELPHIA MBORATGRf RAJ :mJb f DUP030003165 Ti-Pure R-200 -.--.--.-.--.-.~.-----.-i--22 pts* fey weight 325 Mesh Waterground Mica 7S tt n # Tetrasodium Pyrophosphate --0*5 " w n Water 76 tf w 15 Dow Latex 512-0 (45$ Solids) n" n Dow Latex 529-K (45$ Solids) $9 n K Pine Oil 2w " Tributyl Phosphate 60 w w Dowicid G, 10$ Solutioa 6" w n Casein, 15$ Aqueous Solutioa 27 w * B (Cut with 10$ HH4OH based on Casein) $ Solids - 46*3 Binder to Pigment Ratio - 100:100 --___ ------------------------------------------------------------------------------ -------------------------------------,,----- . Ti--Pure R-200 70 pts* fey weight 325 Mesh Waterground Mica 10 " " * Permalith W--421 20 tt w Tetrasodium Pyrophosphate 0*5 " Water 50 B ^ ^ Dow Latex 512-0 (45$ Solids) 67 " n n Dow Latex 529--K (45$ Solids) 67 w w w Pine Oil 1.2 ^ Tributyl Phosphate 3,6 * K n Dowicid G 10$ Solutioa 5 tt st Casein, 15$ Aqueous Solution 22 n n w (Cut with 10$ HH4OH based on Casein) $ Solids - 51*9 Binder to Pigment Ratio - 60:100 The pigments, tetrasodium pyrophosphate and water are mixed at a fairly high speed* The pine oil, tributyl phosphate, Dowieide G and casein are then added* The speed is then reduced and the two latices are blended in. Vigorous agitation at this point causes excessive foaming* Stabilizers other than casein may be found more desirable for individual requirements; these include Methoeel, alpha protein, carboxy methylcellulose, etc* DUP030003166