Document Ywy5w2E5oMerjaDQ7MekJYBE

<*??**-* -Jv ^ : " : : ; -. . -0-:: V\ "., > ) ' '* ' - . ' ' _L- - ' ." .'- ;' .'_ *Jv f/ . HYSTL DEVELOPMENT COMPANY February 28, 1972 Mr. Robert Egan, President Michigan Silo Co. , Inc. P. O. Box 514 . Cherry Road, N. W. Massillon, Ohio 44646 : . ' ' " . ' -' . y Dear Mr. Egan: *- - . .. . ., - : .. ' l am sorry for the delay in answering your letter of February 4th, but it took me a while to dig back through some closets and find a 'ropy tjf my thesis and to determine if T had any other related in formation. I did find an original copy of the thesis, but no other in formation; so my reply to you will be based completely on memory after a thirty-year period has passed. First of all I believe that the cumar formula which you sent with your letter was developed during the summer of 1941, after I had completed my thesis. During that summer I worked for Mr. Brassert and the Concrete Silo Company in Bloomfield. As I recall, I developed this formula as a variation on the general 3ystem3 which I had found to be best during my thesis work at Indiana University. At that time we used the Cumarone-Indene resins because they were inexpensive and had generally good chemical resistance. In the formula you sent the R-16-A and the Paradene No. 2 Flake are both resins of this *vpe which l presume still are offered by the Neville Chemical Company, Pittsburgh, Penn. 1 5225 (41 2-331 -4200). Similarly, at that time the Arociors were used because of their inexpensive price, good ability to plasticize, and excellent chemical resistance. . .: ' \` - - :/ -" .' . ' . ' . - - # In those days the question of Food and Drug Department requirements was not as significant as today. The cumar coating was never tested by another laboratory in connection with any Food and Drug Depart- meat question. We operated on the principle that the coating material resisted the acid of the silage and therefore would be satisfactory for such use. In my present work I have no occasion to closely follow developments concerning the toxicity of materials; however. . CO <> if) p} 5 q STLCOPCB4076673 a^^^gnja^felSfei. Mr. Robert Egan, President -2- ' ' ' 3Tebruary 28,. 1972 I am aware that chlorinated diphenols of which Aroclor is one have been, suspect as far as Food and Drug questions are concerned. I do not have any alternative to suggest to you as a substitute for the Arociors. The only thing I can suggest i-s direct contact with Neville Chemical Company, who may be able to suggest an alternate plasticizer for the cumar resins in such a coating application. The Monsanto Chemical Company makes a number of plasticizers, and they too may be able to offer an alternative. I would imagine that Monsanto has an office in Cleveland, or if not, you C2n contact them at 800 North Lindbergh Blvd, , St. Louis, Mo. 63166 (314-694-1000). I am sorry that I do not have any more detailed or helpful informa tion to offer you; however,. I think either the Neville or Monsanto companies would be the best source of information and suggestions to permit this general type of coating system to meet Food and Drug requirements. * Very truly yours, JRS/vgk J. Robert Sipraul General Manager SW 325632 STLCOPCB4076674