Document 7M3QYn9zXV5VnX8Z7Y29q6188

St oner -Mudge,Inc. GRANT BUILDING PITTSBURGH. PA. November 28, 1934. Dri Robert A. Kehoe, University of Cincinnati, Cincinnati, Ohio. DeaIr Dr. Kehoe: i . Thank you for your letter of November 20th, which arrived during my absence from the city. I have assembled consider able information on the subject of the lead content of our prpduct and submit it herewith. Th e problem might well be divided into two parts. The first part would be the case of white, or tinted coatings, and the se cond, that of the black coatings. The white roller coating lacquer which we would like to use for the inside and outside of food container caps would have the following solid composition* 23. fa Titanium Dioxide %2. Lead Oxide (pbO sublimed) %18.7 Vinyloid Resin 5.75/S Plasticizer This material may safely be estimated to cover about 1,000 square feet of tinplate surface. Its weight is very close to 10 pounds per gallon, so therefore 1 gallon would con tain .2 of a pound, or 90 grams of PbO. On a basis of cover ing 1,000 square feet of area, 1 square foot would contain ajpproximately .09 grams of the lead compound. Therefore a 2" round cap would contain approximately .0018 grams of PbO. In the case of the black coating, there is present t 2.2 fa Carbon Black 1.58 f PbO f15.8 Vinyloid Resin fa5. Plasticizer N6322 Dr. Robert A. Kehoe -2 November 28, 1934, 'Weighing 8 pounds per gallon, there is .126 pounds, or 57 grams, of PbO per gallon. The covering power of the black can be es timated safely at 1,500 square feet per gallon, therefore there is iapproximately .038 grams of PbO present in one square foot of coated surface, or .0008 grams present in the coating on a 2*' cap. ' '- " Vinyloid resins are notable for their insolubility and high re sistance to acid- and alkali-attack. The coatings for this purpose formulated from them are applied by a roller machine and are baked at about 375 F. to eliminate residual solvents and to produce maximum adhesion. What actually happens is that the resin is fluxed to the point where it actually wets the surface of the tinplate. Our tests run back a number of years on this product and we know that a coating stabilized with lead com pounds can be used successfully for the linings of steel con tainers carrying either acid or alkalin solutions. We have a test cup in our laboratory now which has been filled with a %20 solution of Sodium Hydroxide for over two years without the slightest sign of attack. Of the acids, nitric seems to affect the coating most rapidly, visible signs of failure being noted after about a month has elapsed. Hydrochloric and sul phuric acids affect it much less rapidly in 20/i solution. Of the organic acids, formic is probably the most rapid in affect, followed by phenol. Acetic acid will in time cause blisters, but this blistering requires many mouths to produce. Lactic and citric acids have no visible affect over several years %duration. The tests mentioned are all conducted with 20 solu tions. > If is therefore rather strongly impressed upon us that foods packed in containers having linings Containing small percentages of lead could not be injurious to health because the lead could not be drawn from the coating. This is of course a matter of opinion, and no doubt some authorities would feel that the presence of lead, regardless of whether it could be assimilated or not, is a criterion. Mr. Yant suggested asking your opinion on this matter because he felt that you were open-minded and that a condition such as ours is one requiring the use of judgment as well as the application of general rules set down in the past. F-* \> Dr. Robert A. Kehoe -2- November 28, 1934. I do not believe I mentioned it in my first letter, but it would be practical, although somewhat expensive, to overlay both the white and the black coatings with a coat of the Clear resin solu tion. Y/e believe this would effectually insulate the pigmented material from any product with which it might come in contact. This is done in the case of the exterior black coatings as a matter of increasing the thickness of the coating and decreasing the tendency to scratch easily. 3j am sorry that it has been necessary to go into such a lengthy discourse on this matter, but I have not been able to condense ifhe material any further. Yours very truly, f December 3 199h Mr# F* R* Stoner, Jr# Stoner-Mudge, Inc Grant/ Building Pittsburgh* Pa# Dear Mr, Stoners Having gone over tho Information contained in your letter of November 28th, I can not but arrive at the same conclusion which you have reached, namely, that the use of the small amount of load oxide in your product; Is entirely without possibility of harm# Such infinitesimal contamination off food materials or beverages with lead as a consequence of their contact with the type of surface which you describe, would seem to me to be certainly insignificant from an hygienic point of view# As you doubtless know we have found that most food materials and beverages contain measureable amounts of lead# It seems quite certain to mo that it would be impossible to measure any additional amount which might be contributed by a material of the type y o u describe# , I have only one question in connection with your use of Plasticizer* Some of the materials which have been used for this purpose have been found to be toxic. I refer particularly to artho-cresyl- phosphate, and although it seems to me unlikely that you would us this material or that it could gain entrance IntC food materials in toxic amounts, it seems worth whilenevertheless* to raise the question# You will undersfcand, I am sure, that I do not regard it as ariy of m y affair but merely raise the point in passing# Very truly yours, R A K jIS Mob'er'IT'A# Kehoe, M.D# N6322.01