Document YrMO4Mg8KGpZgJ8Zo1LVK4o3k

DOW CHEMICAL U.S.A. Fehruary 18, 1982 ^0. BOX: /'if MIDLAND. MICHIGAN 48640 Kenneth Sutton Technical Center Bird & Son, Inc. East Walpole, MA 02032 Dear Ken: Enclosed you will find two handsheets of composite roofing paper. One was made with Glenwood rock and the other using Georgia Marble No. 9 NCS. The retention of the Glenwood rock was very poor. This is easily observed by looking at the screen side of the sheet. The screen used for the handsheets was 90 mesh and thus caught much of the material, in your mill this would not be the case and this un attached material would permeate and collect throughout the system. In addition this coarse material would quickly ruin felts, screens, pumps, press rolls, etc. The screen analysis of the Glenwood rock shows a high percentage retained on the 80 mesh and larger screens, this is the material causing the problem. Normally we would look for 0 retained on a 50 mesh and a distribution that would pass 70% or more through a 325 mesh. The Georgia Marble material works well, it passes about 93% through a 325 mesh. Macrofil No. 4, produced by calcium Carbonate Products Co., Div. of J. M. Huber, Marble Falls, Texas has been used successfully. There are probably other filler suppliers nearby that could furnish a finer filler. We would very much like to evaluate, before a mill trial, any filler that you find available and feasible to use. A mill trial plan for the Shreveport mill is being developed. As soon as it is completed we will be in touch with you. Sincerely, /jh D. H. Clarey Designed Products 2040 Dow Center 517/636-3280 Enclosures (2) slk AN OPERATING UNIT OF THE DOW CHEMICAL COMPANY BIRD 014000 BIRD 014001 BIRD 014002