Document wD1m5aJqmMmEde8JBXNxOY4w4

Th e Lo w e Br o t h er s Co mpa n y Da yt o n f 2, Oh io , U S. A. M A N U F A C T U R E R S OF P A I N T S . V A R N I S H E S AND LACQUERS September 17, 1946 Dr. Henry. YI. Ryder ~ Kettering Laboratory of Applied Physiology College of Medicine University'of1Cincinnati Cincinnati 19, Ohio Dear Dr. Ryders Most of the information on Asbestine contained herein was obtained from Dr. Kattielio *s book, ''Protective and Decorative Coatings'5, Yclume II. I believe this information vri.ll answer all of the questions in your letter of September 13th to Mr. Kohr. Asbestine is a form of Talc, The term, Talc, is used to describe all forms of.pure hydrous magnesium silicate mineral. Among the Talcs that are used in the paint industry are Soapstone, Potstone, Talc Clay, Asbestine and Yerdolite, '.. The chemical formula is usually written HpMggXSiOg)/., . Geographically, it occurs as follows: 1. As an altered sedimentary rock. 2 . As an altered igneous rock. ' 3. As a definite vein. . Tremolite is undoubtedly the parent mineral, Talc is pseudo morphia after Tremolite, exhibiting a fibrous structure with a certain amount of foliated particles. Talc is mined by open-cut or shaft, and tunnel mining depending upon the character of the deposits. The ore is selected, crushed and ground to the required fineness. The types that are free from iron and grit and low in lime, are the ones suitable for use in paints, Talc is a hard, fibrous wax-like white pigment, The following is a typical analysis for the Asbestine that is used in paints. SiC2 MgO CaO F e 20 3 C2 Loss on ignition 54.0% - 56,0?? 29.6% - 33 5?? 5.0?? - 7.0% Less than 0.3% 0,4?? - 1.15$ 0.3$ - 2.0$ - 2- Specific gravity - 20 C Refractive index pH Partical size 2.85 1.59 8,10 - 9.2 Average 5 - 10 microns Our specification for Asbestine is as .follows; Specific gravity - 70 F. Residue - 325 M screen Residue - 200 11 screen Combine Mg and Ca Silicates Cm as CaO Moisture loss 105 0. Ignition loss Pn Oil absorption ' . 2.85 0.5/ - none BBji minimum 7/o maximum 1% maximum 0> ~ % 9,25? 30,75;;? . Description; Fine texture, medium oil absorption, fibrous -magnesium silicate There are two sources of supply for-the Asbestine that is used in our factory. Our laboratory examination of the various shipments doe not include a chemical analysis, but we are reasonably sure that the composition is quite uniform Slight variations from the standard, result in rather marked changes in the physical properties of the paints in vmich the'Asbestine is used. .Inasmuch as these.properties -remain qui uniform, we can safely assume that the composition and chemical properti of the Asbestine from shipment to shipment are uniform. The. crystalline structure, as viewed under the microscope, is mostly, acicular with a small' percentage of plates. It is definitely of fibrous character.. '' . There have been several articles abstracted in the Abstracts of the "American Chemical Society" that relate to the industrial hazards involved in the mining of Talcs of all types. I believe I have answered all of the questions raised, in your letter of September 13th. In case I have omitted some of the informtio that you desire, do not hesitate to let me know. 1 Very truly yours, THE LOVffi BROTHERS COMPAHY SI F/ oe E. W. F a s i g * ^ General Superintendent