«'/ftL. '^^x United States ¡•i â,A Department of Agriculture Fiberboard Forest Service Agriculture Manufacturing Practices Handbool< No. 640 in the United States C/Sï^ otto Suchsland and George E. Woodson .^- United States Department of Agriculture Forest Service Agriculture Handbook No. 640 Fiberboard Manufacturing Practices intlie United States Otto Suchsland Professor of forestry Michigan State University East Lansing, Michigan and George E. Woodson Associate professor of forest products Louisiana Tech University Ruston, Louisiana EXCHANGE Rec'cfl MAR 2 0 1987 Acknowledgments People who possess the gentle art of encouraging others to Food and Agriculture Organization of the United Nations, Rome: 88, 89, attempt and complete tasks that would otherwise be rejected 134, 160, 161, 168, 253, 256; Forest Products Research Society, Madison, WI: simply because of their seemingly overwhelming size and 12, 92, 126, 198, 201, 210-216, 237, 242, 245, 254, 257, 336-338, 364-370; The Foxboro Co., Foxboro, MN: 115-118. complexity are deserving of far greater praise than is normally International Union of Pure and Applied Chemistry, Oxford: 314. accorded them. Two such individuals are Dr. Peter Koch and Joint Textbook Committee of the Paper Industry, c/o the Canadian Pulp Mr. O. B. Eustis. In addition to constant encouragement, Mr. and Paper Association, Montreal: 40,43, 56, 76, 137, 139-141, 143, 177, 182. Eustis, who is a true expert in the field of fiberboard manufac- KMW AB, Board Machinery Division, Mótala, Sweden: 160, 161; ture, freely shared with us his vast knowledge and experience KMW^ Systems, Atlanta, GA: 65-67. Prof. Thom Maloney, Washington State University, Pullman, WA: 130, in this field. The major contributions of these two gentlemen 157, 162, 193, 195, 196, 214, 217, 218, 220-222, 233, 239; Masonite Corp., are gratefully acknowledged. Chicago: 80, 81, 349-352; McGraw-Hill Book Company, New York: 10, 11, During the preparation of this book we visited many fiber- 15, 39; M-E-C, Neodansha, KS: 194; Miller Freeman Publications, San Fran- board installations in the United States and had many discus- cisco: 163; Morbark Industries, Winn, MI: 34, 35. sions with individuals in the board industry and in associated Peerless, Division of Lear Siegler, Tualatin, OR: 62. Rader Companies, Portland, OR: 64; Rotex, Cincinnati, OH: 59. industries. All of these people took great interest in our effort Siempelkamp Corporation, Marietta, GA: 165-167; Springer-Verlag, and contributed material, suggestions, and special insights Heidelberg, Washington, DC: 17, 18, 164, 190-192, 197, 200, 202, 206, 223, into their own specific areas of expertise. We owe all of these 224, 247; Sprout-Waldron Division of Koppers Co., Muncy, PA: 91, 100, 104, individuals and their companies a great measure of gratitude. 105A; State University of New York, College of Environmental Science and Special appreciation goes to Mr. John Olson, Vice Presi- Forestry at Syracuse: 3; Sunds Defibrator, Minneapolis, MN: 70, 78, 102, 103A&B,310. dent, Abitibi-Price Corporation, who always granted every TAPPI, Atlanta, GA: 37, 46, 53, 60, 61, 77, 93, 125, 131, 316, 319; special request and provided ready access to technical staff and Thermal Engineering Corp., Columbia, SC: 290, 298, 300. to Abitibi's manufacturing facilities at Alpena, MI, and Vance Pubhshing Corp., Prairie View, IL: 79, 171, 261; Van Nostrand Toledo, OH. Reinhold, New York: 19; VEB Fachbuchverlag, Leipzig: 24, 25, 135, 203, We are also indebted to the U.S. Department of Agri- 205, 259, 260. John Wiley & Sons, New York: 14, 16, 27, 74. culture, which through its Southern Forest Experiment Station and its Washington Office provided funding and editorial sup- port. Otto Suchsland and Finally, we like to acknowledge the important part played George Woodson 1986 by our employers, Michigan State University and Louisiana Tech University, which allowed us the necessary freedom of action and provided the atmosphere conducive to such work. The high quality of the drawings is due to the expert serv- ices of Mr. Kevin Sayer, an engineering student at Louisiana Tech University. We thank the following fiberboard manufacturers, equip- ment companies, publishers, and associations for permissions to reprint the fisted illustrations. Ernest H. Abernathy Publishing, 42, 94, 95; Abitibi-Price Corp., Troy, MI: 345, 346, 353 - 355, 362, 363; American Chemical Society, Washington, DC: 23, 83, 175, 189, 207; American Hardboard Association, Palatine, IL: 357-361. C. E. Bauer Combustion Engineering, Springfield, OH: 85-87, 90, 96- 98, 107-110, 113; Bison North America, Atlanta, GA: 219, 230-232. Carthage Machine Co. Southern, Morton, MS: 49, 50; Celotex Corp., Tampa, FL: 371, 372; Coe Manufacturing Company, Painesville, OH: 176, 180, 181. The use of trade or firm names in this publication is for Dorr-Oliver, Inc., Stamford, CN: 111, 112. Edge Wallboard Machinery Company, Downingtown, PA: 144, 145, reader information and does not imply endorsement by the U.S. 150, 151, 154; EX-CELL-0 Micromatic, Holland, MI: 265. Department of Agriculture of any product or service. Contents Page Page 1. Introduction 1 8. Wet-Process Fiberboard Manufacture 98 Concepts 1 General 98 Definitions 4 Forming Machines 98 References 4 The Wet Press 108 2. The Fiberboard Industry 5 Trimming of Wet Fiber Mat Ill Historical Background 5 Hotpressing and Drying 112 Industry Statistics 7 References 134 References 11 9. Dry-Process Fiberboard Manufacture 136 3. Some Chemical Aspects of Fiberboard General 136 Manufacture 13 Manufacture of Dry-Process High- and General 13 Medium-Density Hardboard 137 The Structure and Chemistry of Wood Cells 13 Manufacture of Medium-Density Fiberboard .... 151 Chemical Reactions in Fiberboard Manufacture . 22 Manufacture of Dry-Process Fiberboard by the Chemistry of the Adhesive Bond 24 Continuous Mende Process 160 References 25 Manufacture of Board With Oriented Fibers .... 163 4. Raw Materials 28 References 165 General 28 10. Heat Treatment, Tempering, and Humidification .. 168 The Importance of Fiber Characteristics 28 General 168 Softwoods Versus Hardwoods 31 Improvement of Board Properties 168 Individual Species and Mixtures 32 Industrial Practices 171 Wood Chips 34 References 178 Wood Residues 35 11. Fiberboard Fabricating and Finishing 180 Nonwood Raw Materials 37 General 180 References 37 Fabricating and Finishing of Insulation Board .. 180 5. Preparation of Raw Material 39 Fabricating of Hardboard 182 General 39 Finishing of Hardboard 192 The Millyard 39 References 205 Raw Material Measurement 41 12. Water Use and Treatment 206 Manufacture of Pulp Chips 44 General 206 The Handling of Chips 53 The Water Problem 206 Deterioration of Wood Chips During Storage 55 Treatment Methods 208 The Cleaning of Whole-Tree Chips 56 References 217 References 58 13. Board Properties and Markets 219 6. Pulping Processes 59 General 219 General 59 Properties of Commercial Hardboard 219 The Freeness of Pulp 59 Properties of Dry-Process Mende-Board 221 The Masonite Pulping Process 62 Properties of Commercial Medium-Density Disk Refining 65 Fiberboard 232 Pulp Washers and Screw Presses 80 Viscoelastic Behavior of Fiberboard 233 The Pulping of Bagasse 80 Insulation Board Property Requirements 235 Process Control 82 Application of Hardboard Products 244 References 87 Application of Medium-Density Fiberboard 252 7. Chemical Additives 88 Application of Insulation Board Products 253 General 88 References 255 The Sizing of Fiberboard 88 Index 258 Fiberboard Binders 90 Fire Retardant and Preservative Treatments 91 Industrial Practices 92 References 97 ni IV 1. Introduction This handbook introduces the reader to the Concepts manufacture and fabrication of fiberboard as practiced today in the United States. Several concepts provide a basic approach to the A brief history of this industry is followed by a book's subject. They are discussed here as a starting discussion of some important technological and chemical point to the succeeding chapters. factors as well as a survey of the raw material base. The The term fiberboard applies to a category of sheet bulk of the book describes the equipment and the proc- products that is part of the larger family of wood com- esses including the insulation board process, the wet and position boards (fig. 1). These wood composition boards dry hardboard processes, and the medium-density fiber- are distinct from solid wood in that they are composed of board process. Modern finishing processes are discussed wooden elements of varying sizes held together by an in some detail, and an entire chapter is devoted to the im- adhesive bond. portant subject of water use and water treatment. The The manufacture of these products includes, concluding chapter deals with product properties and ap- therefore, these important steps: the generation of plications including a discussion of various commercial elements or particles (a reduction process) and the recom- standards. bination of these elements in sheet form (a lamination A special effort has been made throughout to il- process). Individual products differ most distinctly in size lustrate the subject with in-plant photos and to explain and shape of the particles used. In plywood, for instance, important concepts by means of schematic drawings. the **particles" are veneer sheets of regular dimensions SPECIFIC GRAVITY SOLID WOOD- .4 .5 .6 .7 .8 .9 1.0 _j i_ L- 1 VENEER PLYWOOD WAFER- BOARD Í2 STRANDBOARD FLAKE- BOARD 5 i PARTICLE- BOARD MDF-DRY HARDBOARD-DRY 5 INSULATIONBOARD MDF-WET HARDBOARD-WET «Xi »^ PAPER ^ 10 20 30 40 50 60 70 ¡ ¡ DENSITY (LBS./FT^) I I INSULATIONBOARD HARDBOARD (AMER. HARDBD. ASSOC. DEFIN.) Figure 1—Classification of wood composition boards by particle size, density, and process type. MDF means medium-density fiberboard. that can easily and systematically be assembled and laminated without densification. ^ ) ) I J í I I I I 1 I I I J ) J / )\ Particle board is based on particles that are very small compared with veneer sheets, but many times larger \\ \ \ \ \ \ \ \ \ \ \\\\\\\ than the wood cell, the basic biological building block of solid wood.